Naval Spent Fuel Rail Shipment Accident Exercise Objectives ...
Office of Environmental Management (EM)
Naval Spent Fuel Rail Shipment Accident Exercise Objectives Naval Spent Fuel Rail Shipment Accident Exercise Objectives PDF icon Naval Spent Fuel Rail Shipment Accident Exercise ...
Categorical Exclusion Determinations: Naval Nuclear Propulsion Program |
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Department of Energy Naval Nuclear Propulsion Program Categorical Exclusion Determinations: Naval Nuclear Propulsion Program Categorical Exclusion Determinations issued by Naval Nuclear Propulsion Program. DOCUMENTS AVAILABLE FOR DOWNLOAD September 25, 2015 CX-014279: Categorical Exclusion Determination Lower Level Guard Post Replacement Project CX(s) Applied: B1.11, B1.15, B2.2 Date: 09/25/2015 Location(s): New York Offices(s): Naval Nuclear Propulsion Program July 6, 2015 CX-013878:
Naval Research Laboratory Technology Marketing Summaries - Energy...
U.S. Department of Energy (DOE) all webpages (Extended Search)
Naval Research Laboratory 8 Technology Marketing Summaries Category Title and Abstract Laboratories Date Solar Photovoltaic Find More Like This Sputtered Thin Film Photovoltaics ...
naval reactors | National Nuclear Security Administration
National Nuclear Security Administration (NNSA)
on Energy and Water Development, visited the Naval Reactors Facility (NRF) at the... ... propulsion plants use a pressurized-water reactor design that has two basic systems: ...
Congressional Delegation visits Naval Reactors Facility | National...
National Nuclear Security Administration (NNSA)
Chuck Fleischmann of the House Appropriations Subcommittee on Energy and Water Development, visited the Naval Reactors Facility (NRF) at the Idaho National Laboratory (INL). ...
Higgins, C.T.; Chapman, R.H.
1984-01-01
The purpose of this project was to determine and evaluate sources of geothermal energy at two military bases in southern California, the Long Beach Naval Shipyard and Naval Station and the Seal Beach Naval Weapons Station. One part of the project focused on the natural geothermal characteristics beneath the naval bases. Another part focused on the geothermal energy produced by oilfield operations on and adjacent to each base. Results of the study are presented here for the US Department of the Navy to use in its program to reduce its reliance on petrolem by the development of different sources of energy. The study was accomplished under a cooperative agreement between the US Department of Energy's San Francisco Operations Office and the Department of the Navy's Naval Weapons Center, China Lake, California, for joint research and development of geothermal energy at military installations.
Naval Waste Package Design Report
M.M. Lewis
2004-03-15
A design methodology for the waste packages and ancillary components, viz., the emplacement pallets and drip shields, has been developed to provide designs that satisfy the safety and operational requirements of the Yucca Mountain Project. This methodology is described in the ''Waste Package Design Methodology Report'' Mecham 2004 [DIRS 166168]. To demonstrate the practicability of this design methodology, four waste package design configurations have been selected to illustrate the application of the methodology. These four design configurations are the 21-pressurized water reactor (PWR) Absorber Plate waste package, the 44-boiling water reactor (BWR) waste package, the 5-defense high-level waste (DHLW)/United States (U.S.) Department of Energy (DOE) spent nuclear fuel (SNF) Co-disposal Short waste package, and the Naval Canistered SNF Long waste package. Also included in this demonstration is the emplacement pallet and continuous drip shield. The purpose of this report is to document how that design methodology has been applied to the waste package design configurations intended to accommodate naval canistered SNF. This demonstrates that the design methodology can be applied successfully to this waste package design configuration and support the License Application for construction of the repository.
More About NNSA's Naval Reactors Office | National Nuclear Security...
National Nuclear Security Administration (NNSA)
More About NNSA's Naval Reactors Office The Naval Nuclear Propulsion Program provides militarily effective nuclear propulsion plants and ensures their safe, reliable and long-lived ...
Naval Nuclear Propulsion Plants | National Nuclear Security Administra...
National Nuclear Security Administration (NNSA)
Naval Nuclear Propulsion Plants In naval nuclear propulsion plants, fissioning of uranium atoms in the reactor core produces heat. Because the fission process also produces...
2012 Annual Planning Summary for Naval Reactors | Department...
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Naval Reactors 2012 Annual Planning Summary for Naval Reactors The ongoing and projected Environmental Assessments and Environmental Impact Statements for 2012 and 2013 within the ...
Development Wells At Fallon Naval Air Station Area (Sabin, Et...
Open Energy Information (Open El) [EERE & EIA]
Fallon Naval Air Station Area (Sabin, Et Al., 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Development Wells At Fallon Naval Air Station...
Naval Spent Fuel Rail Shipment Accident Exercise Objectives
Office of Environmental Management (EM)
NAVAL SPENT FUEL RAIL SHIPMENT ACCIDENT EXERCISE OBJECTIVES * Familiarize stakeholders with the Naval spent fuel ACCIDENT EXERCISE OBJECTIVES Familiarize stakeholders with the ...
2013 Federal Energy and Water Management Award Winner Naval Sea...
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Naval Sea Systems Command 2013 Federal Energy and Water Management Award Winner Naval Sea Systems Command PDF icon fewm13nswcphiladelphiahighres.pdf PDF icon ...
Naval Petroleum Reserves | Department of Energy
For much of the 20th century, the Naval Petroleum and Oil Shale Reserves served as a ... 1900s, the government-owned petroleum and oil shale properties were originally envisioned ...
Special Analysis: Naval Reactor Waste Disposal Pad
Cook, J.R.
2003-03-31
This report presents the results of a special study of the Naval Reactor Waste Disposal Pad located within the boundary of the E-Area Low-Level Waste Facility at the Savannah River Site.
About Naval Reactors | National Nuclear Security Administration | (NNSA)
National Nuclear Security Administration (NNSA)
About Naval Reactors What Is the Naval Nuclear Propulsion Program? The Naval Nuclear Propulsion Program comprises the military and civilian personnel who design, build, operate, maintain, and manage the nuclear-powered ships and the many facilities that support the U.S. nuclear-powered naval fleet. The Program has cradle-to-grave responsibility for all naval nuclear propulsion matters. Program responsibilities are delineated in Presidential Executive Order 12344 of February 1, 1982, and
Nuclear Naval Propulsion: A Feasible Proliferation Pathway?
Swift, Alicia L.
2014-01-31
There is no better time than now to close the loophole in Article IV of the Nuclear Non-proliferation Treaty (NPT) that excludes military uses of fissile material from nuclear safeguards. Several countries have declared their intention to pursue and develop naval reactor technology, including Argentina, Brazil, Iran, and Pakistan, while other countries such as China, India, Russia, and the United States are expanding their capabilities. With only a minority of countries using low enriched uranium (LEU) fuel in their naval reactors, it is possible that a state could produce highly enriched uranium (HEU) under the guise of a nuclear navy while actually stockpiling the material for a nuclear weapon program. This paper examines the likelihood that non-nuclear weapon states exploit the loophole to break out from the NPT and also the regional ramifications of deterrence and regional stability of expanding naval forces. Possible solutions to close the loophole are discussed, including expanding the scope of the Fissile Material Cut-off Treaty, employing LEU fuel instead of HEU fuel in naval reactors, amending the NPT, creating an export control regime for naval nuclear reactors, and forming individual naval reactor safeguards agreements.
Fuel Cell Power Plant Experience Naval Applications
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
clean Fuel Cell Power Plant Experience Naval Applications US Department of Energy/ Office of Naval Research Shipboard Fuel Cell Workshop Washington, DC March 29, 2011 FuelCell Energy, the FuelCell Energy logo, Direct FuelCell and "DFC" are all registered trademarks (®) of FuelCell Energy, Inc. *FuelCell Energy, Inc. *Renewable and Liquid Fuels Experience *HTPEM Fuel Cell Stack for Shipboard APU *Solid Oxide Experience and Applications DOE-ONR Workshop FuelCell Energy, the FuelCell
The Naval Petroleum and Oil Shale Reserves | Department of Energy
The Naval Petroleum and Oil Shale Reserves The Naval Petroleum and Oil Shale Reserves To ensure sufficient fuel for the fleet, the Government began withdrawing probable oil-bearing ...
2014 Annual Planning Summary for the NNSA Naval Reactors
The ongoing and projected Environmental Assessments and Environmental Impact Statements for 2014 and 2015 within the NNSA Naval Reactors.
2013 Annual Planning Summary for the Naval Nuclear Propulsion Program
The ongoing and projected Environmental Assessments and Environmental Impact Statements for 2013 and 2014 within the Naval Nuclear Propulsion Program.
NA 30 - Deputy Administrator for Naval Reactors | National Nuclear Security
National Nuclear Security Administration (NNSA)
Administration | (NNSA) 30 - Deputy Administrator for Naval Reactors NA 30 - Naval Reactors FY15 Year End Report Semi Annual Report FY14 Year End Report Semi Annual Report NX 3 - Naval Reactors Laboratory Field Office FY15 Year End
Naval Nuclear Propulsion | National Nuclear Security Administration
National Nuclear Security Administration (NNSA)
Naval Nuclear Propulsion Klotz visits Bettis Atomic Power Laboratory Lt. Gen. Frank G. Klotz, DOE Undersecretary for Nuclear Security and NNSA Administrator, visited the Bettis Atomic Power Laboratory in West Mifflin, PA on July 2, 2015. Gen. Klotz toured through several test facilities where Bettis personnel reviewed ongoing development efforts to qualify
Naval Nuclear Propulsion Plants | National Nuclear Security Administration
National Nuclear Security Administration (NNSA)
| (NNSA) Naval Nuclear Propulsion Plants In naval nuclear propulsion plants, fissioning of uranium atoms in the reactor core produces heat. Because the fission process also produces radiation, shielding is placed around the reactor to protect the crew. Despite close proximity to a reactor core, a typical crewmember receives less exposure to radiation than one who remains ashore and works in an office building. In naval nuclear propulsion plants, fissioning of uranium atoms in the reactor
DESIGN ANALYSIS FOR THE NAVAL SNF WASTE PACKAGE
T.L. Mitchell
2000-05-31
The purpose of this analysis is to demonstrate the design of the naval spent nuclear fuel (SNF) waste package (WP) using the Waste Package Department's (WPD) design methodologies and processes described in the ''Waste Package Design Methodology Report'' (CRWMS M&O [Civilian Radioactive Waste Management System Management and Operating Contractor] 2000b). The calculations that support the design of the naval SNF WP will be discussed; however, only a sub-set of such analyses will be presented and shall be limited to those identified in the ''Waste Package Design Sensitivity Report'' (CRWMS M&O 2000c). The objective of this analysis is to describe the naval SNF WP design method and to show that the design of the naval SNF WP complies with the ''Naval Spent Nuclear Fuel Disposal Container System Description Document'' (CRWMS M&O 1999a) and Interface Control Document (ICD) criteria for Site Recommendation. Additional criteria for the design of the naval SNF WP have been outlined in Section 6.2 of the ''Waste Package Design Sensitivity Report'' (CRWMS M&O 2000c). The scope of this analysis is restricted to the design of the naval long WP containing one naval long SNF canister. This WP is representative of the WPs that will contain both naval short SNF and naval long SNF canisters. The following items are included in the scope of this analysis: (1) Providing a general description of the applicable design criteria; (2) Describing the design methodology to be used; (3) Presenting the design of the naval SNF waste package; and (4) Showing compliance with all applicable design criteria. The intended use of this analysis is to support Site Recommendation reports and assist in the development of WPD drawings. Activities described in this analysis were conducted in accordance with the technical product development plan (TPDP) ''Design Analysis for the Naval SNF Waste Package (CRWMS M&O 2000a).
More About NNSA's Naval Reactors Office | National Nuclear Security
National Nuclear Security Administration (NNSA)
Administration | (NNSA) More About NNSA's Naval Reactors Office The Naval Nuclear Propulsion Program provides militarily effective nuclear propulsion plants and ensures their safe, reliable and long-lived operation. This mission requires the combination of fully trained U.S. Navy men and women with ships that excel in endurance, stealth, speed, and independence from supply chains. The Naval Nuclear Propulsion Program provides militarily effective nuclear propulsion plants and ensures their
Management of Naval Reactors' Cyber Security Program, OIG-0884
... Specifically, although the site transitioned to training employees using an online service, Naval Reactors Federal employees did not have the necessary application licenses needed ...
NA 30 - Deputy Administrator for Naval Reactors | National Nuclear...
National Nuclear Security Administration (NNSA)
Us Our Operations Management and Budget Office of Civil Rights Workforce Statistics NA 30 - Deputy Administrator for Naval Reactors NA 30 - Deputy Administrator for...
United States Naval Surface Warfare Center | Open Energy Information
Open Energy Information (Open El) [EERE & EIA]
Warfare Center Jump to: navigation, search Hydro | Hydrodynamic Testing Facilities Name United States Naval Surface Warfare Center Address Carderock, 9500 MacArthur Boulevard...
Audit Report - Naval Reactors Information Technology System Developmen...
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
(EBS) project that included procurement, finance, human resources and logistics modules. ... The procurement module alone is expected to cost approximately 12.8 million, and Naval ...
Title 10, Chapter 641 Pertaining to Naval Petroleum Reserves in U.S.C. |
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Department of Energy Title 10, Chapter 641 Pertaining to Naval Petroleum Reserves in U.S.C. Title 10, Chapter 641 Pertaining to Naval Petroleum Reserves in U.S.C. CITE: 10USC7420 CHAPTER 641--NAVAL PETROLEUM RESERVES CITE: 10USC7421 CHAPTER 641--NAVAL PETROLEUM RESERVES CITE: 10USC7422 CHAPTER 641--NAVAL PETROLEUM RESERVES CITE: 10USC7423 CHAPTER 641--NAVAL PETROLEUM RESERVES CITE: 10USC7424 CHAPTER 641--NAVAL PETROLEUM RESERVES CITE: 10USC7425 CHAPTER 641--NAVAL PETROLEUM RESERVES CITE:
Naval Petroleum Reserve No. 3 Disposition Decision Analysis and...
a summary of the analysis supporting DOE's determination to dispose of the Naval Petroleum Reserve No. 3 through sale of all right, title, interest on the open market. RMOTC...
Naval Nuclear Propulsion Plants | National Nuclear Security Administra...
National Nuclear Security Administration (NNSA)
and works in an office building. U.S. naval nuclear propulsion plants use a pressurized-water reactor design that has two basic systems: the primary system and the secondary...
Fuel Cell Power Plant Experience Naval Applications | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Plant Experience Naval Applications Fuel Cell Power Plant Experience Naval Applications Presented at the DOE-DOD Shipboard APU Workshop on March 29, 2011. apu2011_8_wolak.pdf (1.51 MB) More Documents & Publications Fuel Cell Power Plants Biofuel Case Study - Tulare, CA Fuel Cell Power Plants Renewable and Waste Fuels Co-production of Hydrogen and Electricity (A Developer's Perspective)
DOE - Office of Legacy Management -- Norfolk Naval Station - VA 05
Office of Legacy Management (LM)
Norfolk Naval Station - VA 05 FUSRAP Considered Sites Site: NORFOLK NAVAL STATION (VA.05) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: Norfolk , Virginia VA.05-1 Evaluation Year: 1993 VA.05-1 Site Operations: Demonstration of extinguishing a uranium fire at the Fire Fighters School for AEC contractors. VA.05-3 VA.05-2 Site Disposition: Eliminated - Potential for contamination considered remote based on the limited quantity of materials
Naval Spent Nuclear Fuel disposal Container System Description Document
N. E. Pettit
2001-07-13
The Naval Spent Nuclear Fuel Disposal Container System supports the confinement and isolation of waste within the Engineered Barrier System of the Monitored Geologic Repository (MGR). Disposal containers/waste packages are loaded and sealed in the surface waste handling facilities, transferred underground through the access drifts using a rail mounted transporter, and emplaced in emplacement drifts. The Naval Spent Nuclear Fuel Disposal Container System provides long term confinement of the naval spent nuclear fuel (SNF) placed within the disposal containers, and withstands the loading, transfer, emplacement, and retrieval operations. The Naval Spent Nuclear Fuel Disposal Container System provides containment of waste for a designated period of time and limits radionuclide release thereafter. The waste package maintains the waste in a designated configuration, withstands maximum credible handling and rockfall loads, limits the waste form temperature after emplacement, resists corrosion in the expected handling and repository environments, and provides containment of waste in the event of an accident. Each naval SNF disposal container will hold a single naval SNF canister. There will be approximately 300 naval SNF canisters, composed of long and short canisters. The disposal container will include outer and inner cylinder walls and lids. An exterior label will provide a means by which to identify a disposal container and its contents. Different materials will be selected for the waste package inner and outer cylinders. The two metal cylinders, in combination with the Emplacement Drift System, drip shield, and the natural barrier will support the design philosophy of defense-in-depth. The use of materials with different properties prevents a single mode failure from breaching the waste package. The inner cylinder and inner cylinder lids will be constructed of stainless steel while the outer cylinder and outer cylinder lids will be made of high-nickel alloy.
Naval Petroleum and Oil Shale Reserves. Annual report of operations
Not Available
1982-10-01
The Naval Petroleum and Oil Shale Reserves (NPOSR), created to provide a source of liquid fuels for the armed forces during national emergencies, were established by a series of Executive Orders between 1912 and 1924. Following the 1973 to 1974 Arab Oil Embargo, which demonstrated the Nation's vulnerability to oil supply interruptions, the Congress authorized and directed in 1974 that the Reserves be explored and developed to their full economic and productive potential. In October 1981, the President notified the Congress of his decision to extend production of the Naval Petroleum Reserves to April 6, 1985. That decision became final when the Congress did not exercise its authority to disapprove the action. With regard to the Naval Oil Shale Reserves (NOSRs), a program was initiated in 1977 to examine the resource for development and subsequent production should national defense requirements so dictate.
Thermal Evaluation for the Naval SNF Waste Package
T.L. Mitchell
2000-04-25
The purpose of this calculation is to evaluate the thermal performance of the naval long spent nuclear fuel (SNF) waste package (WP) under multiple disposal conditions in a monitored geologic repository (MGR). The scope of this calculation is limited to determination of thermal temperature profiles upon the surface of, and within, the naval long SNF WP. The objective is to develop a temperature profile history within the WP, at time increments up to 10,000 years of emplacement. The results of this calculation are intended to support the Naval SNF WP Analysis and Model Report (AMR) for Site Recommendation (SR). This calculation was performed to the specifications within its Technical Development Plan (TDP) (Ref. 8.16). This calculation is developed and documented in accordance with the AP-3.12Q/REV. 0IICN. 0 procedure, Calculations.
Reactor Safety Planning for Prometheus Project, for Naval Reactors Information
P. Delmolino
2005-05-06
The purpose of this letter is to submit to Naval Reactors the initial plan for the Prometheus project Reactor Safety work. The Prometheus project is currently developing plans for cold physics experiments and reactor prototype tests. These tests and facilities may require safety analysis and siting support. In addition to the ground facilities, the flight reactor units will require unique analyses to evaluate the risk to the public from normal operations and credible accident conditions. This letter outlines major safety documents that will be submitted with estimated deliverable dates. Included in this planning is the reactor servicing documentation and shipping analysis that will be submitted to Naval Reactors.
DOE - Office of Legacy Management -- U S Naval Radiological Defense
Office of Legacy Management (LM)
Laboratory - CA 0-06 Naval Radiological Defense Laboratory - CA 0-06 FUSRAP Considered Sites Site: U. S. NAVAL RADIOLOGICAL DEFENSE LABORATORY (CA.0-06) Eliminated from consideration under FUSRAP - Referred to the DoD Designated Name: Not Designated Alternate Name: None Location: San Francisco , California CA.0-06-1 Evaluation Year: 1987 CA.0-06-1 Site Operations: NRC licensed DoD facility which used small quantities of nuclear materials for R&D purposes and decontaminated ships.
U.S. Naval Station, Guantanamo Bay, Cuba | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Naval Station, Guantanamo Bay, Cuba U.S. Naval Station, Guantanamo Bay, Cuba Fact sheet describes the Energy Savings Performance Contract (ESPC) success story on environmental stewardship and cost savings at the U.S. Naval Station at Guantanamo Bay, Cuba. Download the U.S. Naval Station at Guantanamo Bay, Cuba fact sheet. (316.37 KB) More Documents & Publications Idaho Operations AMWTP Fact Sheet Heating Ventilation and Air Conditioning Efficiency Greenpower Trap Mufflerl System
Final MTI Data Report: Dahlgren Naval Surface Warfare Center
Parker, M.J.
2003-03-17
During the period from February 2001 to August 2002, paved-surface (tarmac) temperatures were collected at the Dahlgren Naval Surface Warfare Center. This effort was led by the Savannah River Technology Center (SRTC), with the assistance of base personnel, as part of SRTC's ground truth mission for the U.S. Department of Energy's Multispectral Thermal Imager (MTI) satellite.
H. Marr
2006-10-25
The purpose of this calculation is to evaluate the thermal performance of the Naval Long and Naval Short spent nuclear fuel (SNF) waste packages (WP) in the repository emplacement drift. The scope of this calculation is limited to the determination of the temperature profiles upon the surfaces of the Naval Long and Short SNF waste package for up to 10,000 years of emplacement. The temperatures on the top of the outside surface of the naval canister are the thermal interfaces for the Naval Nuclear Propulsion Program (NNPP). The results of this calculation are intended to support Licensing Application design activities.
Statement on Defense Nuclear Nonproliferation and Naval Reactors Activities
National Nuclear Security Administration (NNSA)
before the House Committee on Appropriations Subcommittee on Energy & Water Development | National Nuclear Security Administration | (NNSA) Defense Nuclear Nonproliferation and Naval Reactors Activities before the House Committee on Appropriations Subcommittee on Energy & Water Development February 26, 2013 INTRODUCTION Chairman Frelinghuysen, Ranking Member Kaptur, and distinguished members of the Subcommittee, thank you for having me here today to discuss the National Nuclear
Energy use baselining study for the National Naval Medical Center
Parker, G.B.; Halverson, M.A.
1992-04-01
This report provides an energy consumption profile for fourteen buildings at the National Naval Medical Center (NNMC) in Bethesda, Maryland. Recommendations are also made for viable energy efficiency projects funded with assistance from the servicing utility (Potomic Electric Power Company) in the form of rebates and incentives available in their Demand Side Management (DSM) program and through Shared Energy Savings (SES) projects. This report also provides estimates of costs and potential energy savings of the recommended projects.
FY 2012 Budget Hearing Testimony on Nuclear Nonproliferation and Naval
National Nuclear Security Administration (NNSA)
Reactor Programs before the House Appropriations Committee, Energy and Water Development Subcommittee | National Nuclear Security Administration | (NNSA) on Nuclear Nonproliferation and Naval Reactor Programs before the House Appropriations Committee, Energy and Water Development Subcommittee March 02, 2011 Chairman Frelinghuysen and Ranking Member Pastor, thank you for the opportunity to join you today to discuss the investments the President has requested for our nuclear nonproliferation
DOE - Office of Legacy Management -- Naval Research Laboratory - DC 02
Office of Legacy Management (LM)
Research Laboratory - DC 02 FUSRAP Considered Sites Site: NAVAL RESEARCH LABORATORY (DC.02 ) Eliminated from consideration under FUSRAP - Referred to DOD Designated Name: Not Designated Alternate Name: None Location: Washington , D.C. DC.02-4 Evaluation Year: 1987 DC.02-4 Site Operations: Research and development on thermal diffusion. DC.02-4 Site Disposition: Eliminated - No Authority - AEC licensed - Military facility DC.02-4 DC.02-1 Radioactive Materials Handled: Yes Primary Radioactive
1996 environmental monitoring report for the Naval Reactors Facility
1996-12-31
The results of the radiological and nonradiological environmental monitoring programs for 1996 at the Naval Reactors Facility (NRF) are presented in this report. The NRF is located on the Idaho National Engineering and Environmental Laboratory and contains three naval reactor prototypes and the Expended Core Facility, which examines developmental nuclear fuel material samples, spent naval fuel, and irradiated reactor plant components/materials. The results obtained from the environmental monitoring programs verify that releases to the environment from operations at NRF were in accordance with state and federal regulations. Evaluation of the environmental data confirms that the operation of NRF continues to have no adverse effect on the quality of the environment or the health and safety of the general public. Furthermore, a conservative assessment of radiation exposure to the general public as a result of NRF operations demonstrated that the dose received by any member of the public was well below the most restrictive dose limits prescribed by the Environmental Protection Agency (EPA) and the Department of Energy (DOE).
Naval Petroleum and Oil Shale Reserves annual report of operations for fiscal year 1996
1996-12-31
During fiscal year 1996, the Department of Energy continued to operate Naval Petroleum Reserve No. 1 in California and Naval Petroleum Reserve No. 3 in Wyoming through its contractors. In addition, natural gas operations were conducted at Naval Petroleum Reserve No. 3. All productive acreage owned by the Government at Naval Petroleum Reserve No. 2 in California was produced under lease to private companies. The locations of all six Naval Petroleum and Oil Shale Reserves are shown in a figure. Under the Naval Petroleum Reserves Production Act of 1976, production was originally authorized for six years, and based on findings of national interest, the President was authorized to extend production in three-year increments. President Reagan exercised this authority three times (in 1981, 1984, and 1987) and President Bush authorized extended production once (in 1990). President Clinton exercised this authority in 1993 and again in October 1996; production is presently authorized through April 5, 2000. 4 figs. 30 tabs.
Sale of the Elk Hills Naval Petroleum Reserve | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Services » Petroleum Reserves » Naval Reserves » Sale of the Elk Hills Naval Petroleum Reserve Sale of the Elk Hills Naval Petroleum Reserve Energy Secretary Federico Pena (left) and Occidental Petroleum's David Hentschel sign the historic transfer agreement with Patricia Godley, DOE's Assistant Secretary for Fossil Energy, who orchestrated the sale, looking on. Energy Secretary Federico Pena (left) and Occidental Petroleum's David Hentschel sign the historic transfer agreement with Patricia
The Draft EIS evaluates the potential environmental impacts associated with recapitalizing the infrastructure needed to ensure the long-term capability of the Naval Nuclear Propulsion Program (NNPP) to support naval spent nuclear fuel handling capabilities provided by the Expended Core Facility (ECF). Significant upgrades are necessary to ECF infrastructure and water pools to continue safe and environmentally responsible naval spent nuclear fuel handling until at least 2060.
DOE - Office of Legacy Management -- Naval Ordnance Test Station - CA 06
Office of Legacy Management (LM)
Test Station - CA 06 FUSRAP Considered Sites Site: NAVAL ORDNANCE TEST STATION (CA.06) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: China Lake Naval Weapons Center Salt Wells Pilot Plant CA.06-1 Location: Inyokern , California CA.06-1 Evaluation Year: 1987 CA.06-1 Site Operations: Naval facility; experimental development work on shape charges and quality castings on a pilot plant scale. CA.06-1 Site Disposition: Eliminated - No indication that
SPECKLE INTERFEROMETRY AT THE U.S. NAVAL OBSERVATORY. XVII
Mason, Brian D.; Hartkopf, William I.; Wycoff, Gary L. E-mail: wih@usno.navy.mil
2011-08-15
The results of 3362 intensified CCD observations of double stars, made with the 26 inch refractor of the U.S. Naval Observatory, are presented. Each observation of a system represents a combination of over 2000 short-exposure images. These observations are averaged into 1970 mean relative positions and range in separation from 0.''78 to 72.''17, with a mean separation of 14.''76. This is the 17th in this series of papers and covers the period 2010 January 6 through December 20. Also presented are 10 pairs that are resolved for the first time.
Naval Petroleum and Oil Shale Reserves. Annual report of operations, Fiscal year 1992
Not Available
1992-12-31
During fiscal year 1992, the reserves generated $473 million in revenues, a $181 million decrease from the fiscal year 1991 revenues, primarily due to significant decreases in oil and natural gas prices. Total costs were $200 million, resulting in net cash flow of $273 million, compared with $454 million in fiscal year 1991. From 1976 through fiscal year 1992, the Naval Petroleum and Oil Shale Reserves generated more than $15 billion in revenues and a net operating income after costs of $12.5 billion. In fiscal year 1992, production at the Naval Petroleum Reserves at maximum efficient rates yielded 26 million barrels of crude oil, 119 billion cubic feet of natural gas, and 164 million gallons of natural gas liquids. From April to November 1992, senior managers from the Naval Petroleum and Oil Shale Reserves held a series of three workshops in Boulder, Colorado, in order to build a comprehensive Strategic Plan as required by Secretary of Energy Notice 25A-91. Other highlights are presented for the following: Naval Petroleum Reserve No. 1--production achievements, crude oil shipments to the strategic petroleum reserve, horizontal drilling, shallow oil zone gas injection project, environment and safety, and vanpool program; Naval Petroleum Reserve No. 2--new management and operating contractor and exploration drilling; Naval Petroleum Reserve No. 3--steamflood; Naval Oil Shale Reserves--protection program; and Tiger Team environmental assessment of the Naval Petroleum and Oil Shale Reserves in Colorado, Utah, and Wyoming.
Not Available
1994-02-01
Pursuant to the Council on Environmental Quality regulations, which implement the procedural provisions of the National Environmental Policy Act, and the US Department of Energy National Environmental Policy Act regulations, the Department of Energy, Office of Fossil Energy, is issuing a Record of Decision on the continued operation of Naval Petroleum Reserve No. 1, Kern County, California. The Department of Energy has decided to continue current operations at Naval Petroleum Reserve No. 1 and implement additional well drilling, facility development projects and other activities necessary for continued production of Naval Petroleum Reserve No. 1 in accordance with the requirements of the Naval Petroleum Reserves Production Act of 1976. The final Supplemental Environmental Impact Statement, entitled ``Petroleum Production at Maximum Efficient Rate, Naval Petroleum Reserve No. 1 (Elk Hills), Kern County, California (DOE/SEIS-0158),`` was released on September 3, 1993.
Naval Reactors Facility environmental monitoring report, calendar year 2001
2002-12-31
The results of the radiological and nonradiological environmental monitoring programs for 2001 at the Naval Reactors Facility are presented in this report. The results obtained from the environmental monitoring programs verify that releases to the environment from operations at NRF were in accordance with Federal and State regulations. Evaluation of the environmental data confirms that the operation of NRF continues to have no adverse effect on the quality of the environment or the health and safety of the general public. Furthermore, a conservative assessment of radiation exposure to the general public as a result of NRF operations demonstrated that the dose received by any member of the public was well below the most restrictive dose limits prescribed by the U. S. Environmental Protection Agency and the U. S. Department of Energy.
Naval Reactors Facility Environmental Monitoring Report, Calendar Year 2003
2003-12-31
The results of the radiological and nonradiological environmental monitoring programs for 2003 at the Naval Reactors Facility are presented in this report. The results obtained from the environmental monitoring programs verify that releases to the environment from operations at NRF were in accordance with Federal and State regulations. Evaluation of the environmental data confirms that the operation of NRF continues to have no adverse effect on the quality of the environment or the health and safety of the general public. Furthermore, a conservative assessment of radiation exposure to the general public as a result of NRF operations demonstrated that the dose received by any member of the public was well below the most restrictive dose limits prescribed by the U.S. Environmental Protection Agency and the U.S. Department of Energy.
SPECKLE INTERFEROMETRY AT THE U.S. NAVAL OBSERVATORY. XVIII
Mason, Brian D.; Hartkopf, William I.; Friedman, Elizabeth A. E-mail: wih@usno.navy.mil
2012-05-15
The results of 2490 intensified CCD observations of double stars, made with the 26 inch refractor of the U.S. Naval Observatory, are presented. Each observation of a system represents a combination of over 2000 short-exposure images. These observations are averaged into 1462 mean relative positions and range in separation from 0.''56 to 71.''80, with a mean separation of 14.''81. This is the 18th in this series of papers and covers the period 2011 January 3 through 2011 December 18. Also presented are four pairs which are resolved for the first time, thirteen other pairs which appear to be lost, and linear elements for four additional pairs.
Naval Reactors Facility environmental monitoring report, calendar year 1999
2000-12-01
The results of the radiological and nonradiological environmental monitoring programs for 1999 at the Naval Reactors Facility (NRF) are presented in this report. The results obtained from the environmental monitoring programs verify that releases to the environment from operations at NRF were in accordance with Federal and State regulations. Evaluation of the environmental data confirms that the operation of NRF continues to have no adverse effect on the quality of the environment or the health and safety of the general public. Furthermore, a conservative assessment of radiation exposure to the general public as a result of NRF operations demonstrated that the dose received by any member of the public was well below the most restrictive dose limits prescribed by the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Energy (DOE).
1997 environmental monitoring report for the Naval Reactors Facility
1997-12-31
The results of the radiological and nonradiological environmental monitoring programs for 1997 at the Naval Reactors Facility (NRF) are presented in this report. The results obtained from the environmental monitoring programs verify that releases to the environment from operations at NRF were in accordance with state and federal regulations. Evaluation of the environmental data confirms that the operation of NRF continues to have no adverse effect on the quality of the environment or the health and safety of the general public. Furthermore, a conservative assessment of radiation exposure to the general public as a result of NRF operations demonstrated that the dose received by any member of the public was well below the most restrictive dose limits prescribed by the Environmental Protection Agency (EPA) and the Department of Energy (DOE).
Naval Reactors Facility environmental monitoring report, calendar year 2000
2001-12-01
The results of the radiological and nonradiological environmental monitoring programs for 2000 at the Naval Reactors Facility (NRF) are presented in this report. The results obtained from the environmental monitoring programs verify that releases to the environment from operations at NRF were in accordance with Federal and State regulations. Evaluation of the environmental data confirms that the operation of NRF continues to have no adverse effect on the quality of the environment or the health and safety of the general public. Furthermore, a conservative assessment of radiation exposure to the general public as a result of NRF operations demonstrated that the dose received by any member of the public was well below the most restrictive dose limits prescribed by the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Energy (DOE).
SPECKLE INTERFEROMETRY AT THE U.S. NAVAL OBSERVATORY. XIX
Mason, Brian D.; Hartkopf, William I.; Hurowitz, Haley M. E-mail: wih@usno.navy.mil
2013-09-15
The results of 2916 intensified CCD observations of double stars, made with the 26 inch refractor of the U.S. Naval Observatory, are presented. Each observation of a system represents a combination of over two thousand short-exposure images. These observations are averaged into 1584 mean relative positions and range in separation from 0.''54 to 98.''09, with a median separation of 11.''73. This is the 19th in this series of papers and covers the period 2012 January 5 through 2012 December 18. Also presented are 10 pairs that are reported for the first time, 17 pairs that appear to be lost, linear elements for 18 pairs, and orbital elements for 2 additional pairs.
Cronk, T.A.; Smuin, D.R.; Schlosser, R.M.
1991-11-01
This technical memorandum develops process options which are appropriate for environmental restoration activities at Naval Air Station Fallon (NAS Fallon), Nevada. Introduction of contaminants to the environment has resulted from deliberate disposal activities (both through dumping and landfilling) and accidental spills and leaks associated with normal activities at NAS Fallon over its lifetime of operation. Environmental sampling results indicate that the vast majority of contaminants of concern are petroleum hydrocarbon related. These contaminants include JP-4, JP-5, leaded and unleaded gasoline, waste oils and lubricants, hydraulic fluids, and numerous solvents and cleaners. The principal exposure pathways of concern associated with NAS Fallon contaminants appear to be the surface flows and shallow drainage systems to which the base contributes. Available data indicate NAS Fallon IR Program sites are not contributing excessive contamination to surface flows emanating from the base. Contaminants appear to be contained in a relatively immobile state in the shallow subsurface with little or no contaminant migration off site.
D. Kokkinos
2005-04-28
The purpose of this letter is to request Naval Reactors comments on the nuclear reactor high tier requirements for the PROMETHEUS space flight reactor design, pre-launch operations, launch, ascent, operation, and disposal, and to request Naval Reactors approval to transmit these requirements to Jet Propulsion Laboratory to ensure consistency between the reactor safety requirements and the spacecraft safety requirements. The proposed PROMETHEUS nuclear reactor high tier safety requirements are consistent with the long standing safety culture of the Naval Reactors Program and its commitment to protecting the health and safety of the public and the environment. In addition, the philosophy on which these requirements are based is consistent with the Nuclear Safety Policy Working Group recommendations on space nuclear propulsion safety (Reference 1), DOE Nuclear Safety Criteria and Specifications for Space Nuclear Reactors (Reference 2), the Nuclear Space Power Safety and Facility Guidelines Study of the Applied Physics Laboratory.
US Department of Energy Naval petroleum reserve number 1. Financial statement audit
1997-03-01
The Naval Petroleum and Oil Shale Reserves (NPOSR) produces crude oil and associated hydrocarbons from the Naval Petroleum Reserves (NPR) numbered 1, 2, and 3, and the Naval Oil Shale Reserves numbered 1, 2, and 3 in a manner to achieve the greatest value and benefits to the United States taxpayer. NPOSR was established by a series of Executive Orders in the early 1900s as a future source of liquid fuels for the military. NPOSR remained largely inactive until Congress, responding to the Arab oil embargo of 1973-74, passed the Naval Petroleum Reserves Production Act of 1976. The law authorized production for six years. Thereafter, NPOSR production could be reauthorized by the President in three-year increments. Since enactment of the law, every President has determined that continuing NPOSR production is in the nation`s best interest. NPOSR currently is authorized to continue production through April 5, 2000.
EA-1008: Continued Development of Naval Petroleum Reserve No. 3 (Sitewide), Natrona County, Wyoming
This EA evaluates the environmental impacts of the proposal to continue development of the U.S. Department of Energy's Naval Petroleum Reserve No. 3 located in Natrona County, Wyoming over the next...
EA-1236: Preparation for Transfer of Ownership of Naval Petroleum Reserve No. 3, Natrona County, WY
Final Sitewide Environmental Assessment (EA) This Sitewide EA evaluates activities that DOE would conduct in anticipation of possible transfer of Naval Petroleum Reserve No. 3 (NPR-3) out of Federal operation.
EIS-0068: Development Policy Options for the Naval Oil Shale Reserves in Colorado
Office of Energy Efficiency and Renewable Energy (EERE)
The U.S. Department of Energy Office of Naval Petroleum and Oil Shale Reserves prepared this programmatic statement to examine the environmental and socioeconomic impacts of development projects on the Naval Oil Shale Reserve 1, and examine select alternatives, such as encouraging production from other liquid fuel resources (coal liquefaction, biomass, offshore oil and enhanced oil recovery) or conserving petroleum in lieu of shale oil production.
2013 Federal Energy and Water Management Award Winner Naval Sea Systems
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Command | Department of Energy Naval Sea Systems Command 2013 Federal Energy and Water Management Award Winner Naval Sea Systems Command fewm13_nswcphiladelphia_highres.pdf (5.43 MB) fewm13_nswcphiladelphia.pdf (1.75 MB) More Documents & Publications CX-005670: Categorical Exclusion Determination U.S. Navy Marine Diesel Engines and the Environment - Part 1 EIS-0259: Record of Decision
DOE - Office of Legacy Management -- Naval Ordnance Laboratory - MD 0-03
Office of Legacy Management (LM)
Laboratory - MD 0-03 FUSRAP Considered Sites Site: NAVAL ORDNANCE LABORATORY (MD.0-03 ) Eliminated from further consideration under FUSRAP - Referred to DOD Designated Name: Not Designated Alternate Name: Naval Ordnance Laboratory - White Oak Location: White Oak Area , Silver Spring , Maryland MD.0-03-1 MD.0-03-2 Evaluation Year: 1987 MD.0-03-2 Site Operations: Research and development - may have involved radioactive materials because the site was identified on a 1955 Accountability Station
DOE - Office of Legacy Management -- Naval Petroleum Reserve No 3 - 046
Office of Legacy Management (LM)
Petroleum Reserve No 3 - 046 FUSRAP Considered Sites Site: Naval Petroleum Reserve No. 3 (046) More information at http://www.fossil.energy.gov/ Designated Name: Not Designated under FUSRAP Alternate Name: Naval Petroleum Reserve No 3 Landfill/Landfarm Location: Natrona County, Wyoming Evaluation Year: Not considered for FUSRAP - in another program Site Operations: Energy research Site Disposition: Site managed by DOE Office of Fossil Energy Radioactive Materials Handled: Unknown Primary
Alternative energy conversion demonstration laboratory at U. S. Naval Academy
Wu, C.
1983-12-01
This paper describes an alternative energy conversion demonstration laboratory which supplements classroom theory in a senior engineering elective course in energy conversion in the Department of Mechanical Engineering at the U.S. Naval Academy. Oil, nuclear energy, and other conventional sources of power have been the dominant sources for industrial society and the U.S. Navy, and will continue to be so for the foreseeable future. There are other possibilities, however, including wind power, solar power, ocean thermal power and tidal power. A need for alternative sources of energy for the Navy was recognized at the time of the Arab oil embargo in 1973, and an academic program in alternative energy has been developed to help satisfy that need. Specific demonstrations included in this paper are as follows: Mechanical modeling of the depletion of energy reserve, Computer graphic simulation of energy consumption and energy resource exhaust, Wind model, Thermax helius rotor wind machine, Solar breeze - an electric sailboat project, Vertical axis wind turbine, Helicopter, airplane propeller and windmill models test in wind tunnel, Ocean Thermal Energy Conversion Device Demonstration, Pneumatic Wave Energy Conversion Device Demonstration, Chemical Energy Storage Device Demonstration, Solar Energy Demonstration.
Renewable Energy Optimization Report for Naval Station Newport
Robichaud, R.; Mosey, G.; Olis, D.
2012-02-01
In 2008, the U.S. Environmental Protection Agency (EPA) launched the RE-Powering America's Land initiative to encourage the development of renewable energy (RE) on potentially contaminated land and mine sites. As part of this effort, EPA is collaborating with the U.S. Department of Energy's (DOE's) National Renewable Energy Laboratory (NREL) to evaluate RE options at Naval Station (NAVSTA) Newport in Newport, Rhode Island. NREL's Renewable Energy Optimization (REO) tool was utilized to identify RE technologies that present the best opportunity for life-cycle cost-effective implementation while also serving to reduce energy-related carbon dioxide emissions and increase the percentage of RE used at NAVSTA Newport. The technologies included in REO are daylighting, wind, solar ventilation preheating (SVP), solar water heating, photovoltaics (PV), solar thermal (heating and electric), and biomass (gasification and cogeneration). The optimal mix of RE technologies depends on several factors including RE resources; technology cost and performance; state, utility, and federal incentives; and economic parameters (discount and inflation rates). Each of these factors was considered in this analysis. Technologies not included in REO that were investigated separately per NAVSTA Newport request include biofuels from algae, tidal power, and ground source heat pumps (GSHP).
SPECKLE INTERFEROMETRY AT THE U.S. NAVAL OBSERVATORY. XVI
Mason, Brian D.; Hartkopf, William I.; Wycoff, Gary L. E-mail: wih@usno.navy.mil
2011-05-15
The results of 1031 speckle-interferometric observations of double stars, made with the 26 inch refractor of the U.S. Naval Observatory, are presented. Each speckle-interferometric observation of a system represents a combination of over two thousand short-exposure images. These observations are averaged into 457 mean relative positions and range in separation from 0.''15 to 16.''94, with a median separation of 3.''03. The range in V-band magnitudes for the primary (secondary) of observed targets is 3.1-12.9 (3.2-13.3). This is the sixteenth in a series of papers presenting measurements obtained with this system and covers the period 2009 January 12 through 2009 December 17. Included in these data are 12 older measurements whose positions were previously deemed possibly aberrant, but are no longer classified this way following a confirming observation. Also, 10 pairs with a single observation are herein confirmed. This paper also includes the first data obtained using a new ICCD with fiber optic cables.
THE FOURTH US NAVAL OBSERVATORY CCD ASTROGRAPH CATALOG (UCAC4)
Zacharias, N.; Finch, C. T.; Bartlett, J. L.; Girard, T. M.; Henden, A.; Monet, D. G.; Zacharias, M. I.
2013-02-01
The fourth United States Naval Observatory (USNO) CCD Astrograph Catalog, UCAC4, was released in 2012 August (double-sided DVD and CDS data center Vizier catalog I/322). It is the final release in this series and contains over 113 million objects; over 105 million of them with proper motions (PMs). UCAC4 is an updated version of UCAC3 with about the same number of stars also covering all-sky. Bugs were fixed, Schmidt plate survey data were avoided, and precise five-band photometry was added for about half the stars. Astrograph observations have been supplemented for bright stars by FK6, Hipparcos, and Tycho-2 data to compile a UCAC4 star catalog complete from the brightest stars to about magnitude R = 16. Epoch 1998-2004 positions are obtained from observations with the 20 cm aperture USNO Astrograph's 'red lens', equipped with a 4k by 4k CCD. Mean positions and PMs are derived by combining these observations with over 140 ground- and space-based catalogs, including Hipparcos/Tycho and the AC2000.2, as well as unpublished measures of over 5000 plates from other astrographs. For most of the faint stars in the southern hemisphere, the first epoch plates from the Southern Proper Motion program form the basis for PMs, while the Northern Proper Motion first epoch plates serve the same purpose for the rest of the sky. These data are supplemented by 2MASS near-IR photometry for about 110 million stars and five-band (B, V, g, r, i) APASS data for over 51 million stars. Thus the published UCAC4, as were UCAC3 and UCAC2, is a compiled catalog with the UCAC observational program being a major component. The positional accuracy of stars in UCAC4 at mean epoch is about 15-100 mas per coordinate, depending on magnitude, while the formal errors in PMs range from about 1 to 10 mas yr{sup -1} depending on magnitude and observing history. Systematic errors in PMs are estimated to be about 1-4 mas yr{sup -1}.
Boiler Upgrades and Decentralizing Steam Systems Save Water and Energy at Naval Air Station Oceana
Office of Energy Efficiency and Renewable Energy (EERE)
Case study details Naval Air Station Oceana findings that its heating needs could be met more efficiently by replacing its central plant with a combination of distributed boilers and ground source heat pumps. The results saved more than 1 million MBtu in energy and 19,574 Kgal of water annually.
Mitigation action plan sale of Naval Petroleum Reserve No. 1 (Elk Hills) Kern County, California
1998-01-01
Naval Petroleum Reserve No. 1 (NPR-1, also called {open_quotes}Elk Hills{close_quotes}), a Federally-owned oil and gas production field in Kern County, California, was created by an Executive Order issued by President Taft on September 2, 1912. He signed another Executive Order on December 13, 1912, to establish Naval Petroleum Reserve No. 2 (NPR-2), located immediately south of NPR-1 and containing portions of the town of Taft, California. NPR-1 was not developed until the 1973-74 oil embargo demonstrated the nation`s vulnerability to oil supply interruptions. Following the embargo, Congress passed the Naval Petroleum Reserves Production Act of 1976 which directed that the reserve be explored and developed to its fall economic potential at the {open_quotes}maximum efficient rate{close_quotes} (MER) of production. Since Elk Hills began full production in 1976, it has functioned as a commercial operation, with total revenues to the Federal government through FY 1996 of $16.4 billion, compared to total exploration, development and production costs of $3.1 billion. In February 1996, Title 34 of the National Defense Authorization Act for Fiscal Year 1996 (P.L. 104-106), referred to as the Elk Hills Sales Statute, directed the Secretary of Energy to sell NPR-1 by February 10, 1998.The Secretary was also directed to study options for enhancing the value of the other Naval Petroleum and Oil Shale Reserve properties such as NPR-2, located adjacent to NPR-1 in Kern County- Naval Petroleum Reserve No. 3 (NPR-3) located in Natrona County, Wyoming; Naval Oil Shale Reserves No. 1 and No. 3 (NOSR-1 and NOSR-3) located in Garfield County, Colorado; and Naval Oil Shale Reserve No. 2 (NOSR-2) located in Uintah and Carbon Counties, Utah. The purpose of these actions was to remove the Federal government from the inherently non-Federal function of operating commercial oil fields while making sure that the public would obtain the maximum value from the reserves.
This EA evaluates the environmental impacts of a proposal for a Natural Gas Protection Program for Naval Oil Shale Reserves Nos. 1 and 3 which would be implemented over a five-year period that...
Investigation on the continued production of the Naval Petroleum Reserves beyond April 5, 1991
Not Available
1990-09-01
The authority to produce the Naval Petroleum Reserves (NPRs) is due to expire in April 1991, unless extended by Presidential finding. As provided in the Naval Petroleum Reserves Production act of 1976 (Public Law 94-258), the President may continue production of the NPRs for a period of up to three years following the submission to Congress, at least 180 days prior to the expiration of the current production period, of a report that determines that continued production of the NPRs is necessary and a finding by the President that continued production is in the national interest. This report assesses the need to continue production of the NPRs, including analyzing the benefits and costs of extending production or returning to the shut-in status that existed prior to 1976. This continued production study considers strategic, economic, and energy issues at the local, regional, and national levels. 15 figs., 13 tabs.
Investigation of waste rag generation at Naval Station Mayport. Project report, May 1990-July 1993
1995-08-01
The report presents the results of an investigation examining pollution prevention alternatives for reducing the volume of waste rags generated at Naval Station Mayport, located near Jacksonville Beach, Florida. The report recommends five specific pollution prevention alternatives: better operating practices, installation of equipment cleaning stations to remove contaminants normally removed with rags; replacement of SERVE MART rags with disposable wipers; use of recyclable rats for oil and great removal; and confirmation that used rags are fully contaminated prior to disposal.
DOE - Office of Legacy Management -- Naval Oil Shale Reserves Site - 013
Office of Legacy Management (LM)
Oil Shale Reserves Site - 013 FUSRAP Considered Sites Site: Naval Oil Shale Reserves Site (013 ) More information at http://www.fossil.energy.gov/ Designated Name: Not Designated under FUSRAP Alternate Name: None Location: Anvil Points, Colorado Evaluation Year: Not considered for FUSRAP - in another program Site Operations: Energy research Site Disposition: Site previously managed by DOE Office of Fossil Energy; transferred to Bureau of Land Management Radioactive Materials Handled: Unknown
1997-03-01
The Naval Petroleum and Oil Shale Reserves (NPOSR) produces crude oil and associated hydrocarbons from the Naval Petroleum Reserves (NPR) numbered 1, 2, and 3, and the Naval Oil Shale Reserves (NOSR) numbered 1, 2, and 3 in a manner to achieve the greatest value and benefits to the US taxpayer. NPOSR consists of the Naval Petroleum Reserve in California (NPRC or Elk Hills), which is responsible for operations of NPR-1 and NPR-2; the Naval Petroleum Oil Shale Reserve in Colorado, Utah, and Wyoming (NPOSR-CUW), which is responsible for operations of NPR-3, NOSR-1, 2, and 3 and the Rocky Mountain Oilfield Testing Center (RMOTC); and NPOSR Headquarters in Washington, DC, which is responsible for overall program direction. Each participant shares in the unit costs and production of hydrocarbons in proportion to the weighted acre-feet of commercially productive oil and gas formations (zones) underlying the respective surface lands as of 1942. The participating shares of NPR-1 as of September 30, 1996 for the US Government and Chevron USA, Inc., are listed. This report presents the results of the independent certified public accountants` audit of the Department of Energy`s (Department) Naval Petroleum and Oil Shale Reserves (NPOSR) financial statements as of September 30, 1996.
This Final Environmental Impact Statement addresses six general alternative systems for the loading, storage, transport, and possible disposal of naval spent nuclear fuel following examination.
Naval Petroleum and Oil Shale Reserves. Annual report of operations, Fiscal year 1993
Not Available
1993-12-31
During fiscal year 1993, the reserves generated $440 million in revenues, a $33 million decrease from the fiscal year 1992 revenues, primarily due to significant decreases in oil and natural gas prices. Total costs were $207 million, resulting in net cash flow of $233 million, compared with $273 million in fiscal year 1992. From 1976 through fiscal year 1993, the Naval Petroleum and Oil Shale Reserves generated $15.7 billion in revenues for the US Treasury, with expenses of $2.9 billion. The net revenues of $12.8 billion represent a return on costs of 441 percent. See figures 2, 3, and 4. In fiscal year 1993, production at the Naval Petroleum and Oil Shale Reserves at maximum efficient rates yielded 25 million barrels of crude oil, 123 billion cubic feet of natural gas, and 158 million gallons of natural gas liquids. The Naval Petroleum and Oil Shale Reserves has embarked on an effort to identify additional hydrocarbon resources on the reserves for future production. In 1993, in cooperation with the US Geological Survey, the Department initiated a project to assess the oil and gas potential of the program`s oil shale reserves, which remain largely unexplored. These reserves, which total a land area of more than 145,000 acres and are located in Colorado and Utah, are favorably situated in oil and gas producing regions and are likely to contain significant hydrocarbon deposits. Alternatively the producing assets may be sold or leased if that will produce the most value. This task will continue through the first quarter of fiscal year 1994.
DOE - Office of Legacy Management -- Naval Gun Factory and Bureau of
Office of Legacy Management (LM)
Ordnance - DC 0-01 Gun Factory and Bureau of Ordnance - DC 0-01 FUSRAP Considered Sites Site: NAVAL GUN FACTORY AND BUREAU OF ORDNANCE (DC.0-01) Eliminated from consideration under FUSRAP - Referred to DOD Designated Name: Not Designated Alternate Name: None Location: Washington , D.C. DC.0-01-1 Evaluation Year: 1987 DC.0-01-1 Site Operations: Designed guns and nuclear projectiles. DC.0-01-1 Site Disposition: Eliminated - No Authority DC.0-01-1 Radioactive Materials Handled: None Indicated
National Nuclear Security Administration (NNSA)
6%2A en Powering the Nuclear Navy http:www.nnsa.energy.govourmissionpoweringnavy
National Nuclear Security Administration (NNSA)
6%2A en Powering the Nuclear Navy http:nnsa.energy.govourmissionpoweringnavy
1998-05-01
The Naval Petroleum Reserves in California (NPRC) are oil fields administered by the DOE in the southern San Joaquin Valley of California. Four federally endangered animal species and one federally threatened plant species are known to occur on NPRC: San Joaquin kit fox (Vulpes macrotis mutica), blunt-nosed leopard lizard (Gambelia silus), giant kangaroo rat (Dipodomys ingens), Tipton kangaroo rat (Dipodomys nitratoides), and Hoover`s wooly-star (Eriastrum hooveri). All five are protected under the Endangered Species Act (ESA) of 1973. The DOE/NPRC is obliged to determine whether actions taken by their lessees on Naval Petroleum Reserve No. 2 (NPR-2) will have any effects on endangered species or their habitats. The primary objective of the Endangered Species and Cultural Resources Program is to provide NPRC with the scientific expertise necessary for compliance with the ESA, the National Environmental Policy Act (NEPA), and the National Historic Preservation Act (NHPA). The specific objective of this report is to summarize progress, results, and accomplishments of the program during fiscal year 1997 (FY97).
Office of Energy Efficiency and Renewable Energy (EERE)
The Office of Naval Petroleum and Oil Shale Reserves developed this supplement to a Department of Navy statement to evaluate the environmental impacts associated with a modified design of a proposed 250,000 barrels per day crude oil conveyance system from Naval Petroleum Reserve No. 1 to connect to the proposed SOHIO West Coast to Midcontinent Pipeline at Rialto, California.
The U.S. Department of Energy developed this statement, the supplement to DOE/EIS-0158, to analyze the environmental and socioeconomic impacts of the sale of Naval Petroleum Reserve No. 1 in Kern County, California to Occidental Petroleum Corporation.
This EA, prepared by the Department of the Navy, evaluates the environmental impacts of the disposal of decommissioned, defueled, naval reactor plants from the USS Enterprise at DOE’s Hanford Site, Richland, Washington. DOE participated as a cooperating agency in the preparation of this EA. The Department of the Navy issued its FONSI on August 23, 2012.
Not Available
1989-02-01
This report presents the preliminary environmental findings from the first phase of the Environmental Survey of the US Department of Energy (DOE) Naval Petroleum Reserves 1 (NPR-1) and 2 (NPR-2) in California (NPRC), conducted May 9--20, 1988. The Survey is being conducted by an interdisciplinary team of environmental specialists, led and managed by the Office of Environment Safety and Health's Office of Environmental Audit. Individual team specialists are outside experts being supplied by a private contractor. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with NPRC. The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. The on-site phase of the Survey involved the review of existing site environmental data, observations of the operations carried on at NPRC, and interviews with site personnel. 120 refs., 28 figs., 40 tabs.
Eissler, A.W.; Ferrel, T.W.; Bloom, T.F.; Fajen, J.M.
1985-06-24
Breathing-zone samples were analyzed for organotin compounds, copper, and xylene during spray application of organotin containing marine antifouling paint at Norfolk Naval Shipyard, Portsmouth, Virginia, March, 1984. The survey was part of a NIOSH study of occupational exposures to organotin compounds, conducted as a component of an assessment to determine the feasibility of conducting a study of reproductive effects. Company personnel records were reviewed. Work practices were observed. The authors conclude that a potential exists for exposures to organotins and copper. As all employees were wearing respiratory protective equipment, actual exposures may be less than that indicated by the analytical data. The facility could contribute 16 potentially exposed workers to the reproductive effects study.
Assessment of Fleet Inventory for Naval Air Station Whidbey Island. Task 1
Schey, Stephen; Francfort, Jim
2015-06-01
Task 1includes a survey of the inventory of non-tactical fleet vehicles at Naval Air Station Whidbey Island (NASWI) to characterize the fleet. This information and characterization are used to select vehicles for monitoring that takes place during Task 2. This monitoring involves data logging of vehicle operation in order to identify the vehicle’s mission and travel requirements. Individual observations of these selected vehicles provide the basis for recommendations related to PEV adoption. It also identifies whether a battery electric vehicle or plug-in hybrid electric vehicle (collectively referred to as PEVs) can fulfill the mission requirements and provide observations related to placement of PEV charging infrastructure. This report provides the results of the assessments and observations of the current non-tactical fleet, fulfilling the Task 1 requirements.
Not Available
1994-06-01
This volume contains the following attachments: transportation of Naval spent nuclear fuel; description of Naval spent nuclear receipt and handling at the Expended Core Facility at the Idaho National Engineering Laboratory; comparison of storage in new water pools versus dry container storage; description of storage of Naval spent nuclear fuel at servicing locations; description of receipt, handling, and examination of Naval spent nuclear fuel at alternate DOE facilities; analysis of normal operations and accident conditions; and comparison of the Naval spent nuclear fuel storage environmental assessment and this environmental impact statement.
DOE prepared an EA that assesses the potential environmental impacts of the proposed discontinuation of DOE operations at the Rocky Mountain Oilfield Testing Center (RMOTC) and the proposed divestiture of Naval Petroleum Reserve Number 3 (NPR-3)
Huffman, S.
2011-10-01
A Study Prepared in Partnership with the Environmental Protection Agency for the RE-Powering America's Land Initiative: Siting Renewable Energy on Potentially Contaminated Land and Mine Sites. The Brunswick Naval Air Station is a naval air facility and Environmental Protection Agency (EPA) Super Fund site that is being cleaned up, and closed down. The objective of this report is not only to look at the economics of individual renewable energy technologies, but also to look at the systemic benefits that can be gained when cost-effective renewable energy technologies are integrated with other systems and businesses in a community; thus multiplying the total monetary, employment, and quality-of-life benefits they can provide to a community.
Not Available
1994-08-01
The Department of Energy monitors commercial natural gas production activities along the boundaries of Naval Oil Shale Reserve No. 1 and Naval Oil Shale Reserve No. 3, which are located in Garfield County, Colorado, and were created in the early part of this century to provide a future source of shale oil for the military. In response to the private sector`s drilling of natural gas wells along the south and southwest boundaries of the Reserves, which began in the early 1980`s, the Department developed a Natural Gas Protection Program to protect the Government`s resources from drainage due to the increasing number of commercial gas wells contiguous to Naval Oil Shale Reserve No. 3. This report provides an update of the Gas Protection Program being implemented and the agreements that have been placed in effect since December 19, 1991, and also includes the one communitized well containing Naval Petroleum Reserve No. 3 lands. The Protection Program employs two methods to protect the Government`s resources: (1) sharing with the private sector in the costs and production of wells by entering into ``communitization`` agreements; and (2) drilling wholly-owned Government wells to ``offset`` commercial wells that threaten to drain natural gas from the Reserves. The methods designed to protect the Government`s resources are achieving their objective of abating gas drainage and migration. As a result of the Protection Program, the Department of Energy is able to produce natural gas and either sell its share on the open market or transfer it for use at Government facilities. The Natural Gas Protection Program is a reactive, ongoing program that is continually revised as natural gas transportation constraints, market conditions, and nearby commercial production activities change.
Not Available
1989-02-01
This report presents the preliminary environmental findings from the first phase of the Environmental Survey of the United States Department of Energy (DOE) Naval Petroleum and Oil Shale Reserves in Colorado, Utah, and Wyoming (NPOSR-CUW) conducted June 6 through 17, 1988. NPOSR consists of the Naval Petroleum Reserve No. 3 (NPR-3) in Wyoming, the Naval Oil Shale Reserves No. 1 and 3 (NOSR-1 and NOSR-3) in Colorado and the Naval Oil Shale Reserve No. 2 (NOSR-2) in Utah. NOSR-2 was not included in the Survey because it had not been actively exploited at the time of the on-site Survey. The Survey is being conducted by an interdisciplinary team of environmental specialists, lead and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. Individual team specialists are outside experts being supplied by a private contractor. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with NPOSR. The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations carried on at NPOSR and interviews with site personnel. The Survey team has developed a Sampling and Analysis Plan to assist in further assessing specific environmental problems identified at NOSR-3 during the on-site Survey. There were no findings associated with either NPR-3 or NOSR-1 that required Survey-related sampling and Analysis. The Sampling and Analysis Plan will be executed by Idaho National Engineering Laboratory. When completed, the results will be incorporated into the Environmental Survey Summary report. The Summary Report will reflect the final determinations of the NPOSR-CUW Survey and the other DOE site-specific Surveys. 110 refs., 38 figs., 24 tabs.
1995-07-01
The Secretary of Energy is required by law to explore, prospect, conserve, develop, use, and operate the Naval Petroleum and Oil Shale Reserves. The Naval Petroleum Reserves Production Act of 1976 (Public Law 94-258), requires that the Naval Petroleum Reserves be produced at their maximum efficient rate (MER), consistent with sound engineering practices, for a period of six years. To fulfill this mission, DOE is proposing continued development activities which would include the drilling of approximately 250 oil production and injection (gas, water, and steam) wells, the construction of between 25 and 30 miles of associated gas, water, and steam pipelines, the installation of several production and support facilities, and the construction of between 15 and 20 miles of access roads. These drilling and construction estimates include any necessary activities related to the operation of the Rocky Mountain Oilfield Testing Center (RMOTC). The purpose of RMOTC will be to provide facilities and necessary support to government and private industry for testing and evaluating new oilfield and environmental technologies, and to transfer these results to the petroleum industry through seminars and publications. Continued development activities either have no potential to result in adverse environmental impacts or would only result in adverse impacts that could be readily mitigated. The small amounts of disturbed surface area will be reclaimed to its original natural state when production operations terminate. The preparation of an environmental impact statement is not required, and the DOE is issuing this Finding of No Significant Impact (FONSI). 73 refs.
1997-12-31
The Naval Petroleum and Oil Shale Reserves (NPOSR) produces crude oil and associated hydrocarbons from the Naval Petroleum Reserve No. 1 (NPR-1) in a manner to achieve the greatest value and benefits to the US taxpayer. As required by the 1996 National Defense Authorization Act, the Department of Energy offered NPR-1 for sale during FY 1997. DOE structured the sale so as to offer two types of ownership segments: one operatorship segment, consisting of 74% of the US interest in NPR-1, and 13 nonoperating segments, each consisting of 2% of the US interest. Potential purchasers could bid on one, some, or all of the segments. If a single purchaser wanted to buy all of the Government`s interest, then its bid would have to exceed the total of the highest bids for all of the individual segments. Bids were due October 1, 1997, at which time DOE received 22 bids from 15 parties acting alone or in concert. The report and management letter present the results of the independent certified public accountants` audits of the Department of Energy`s Naval Petroleum Reserve Number 1 (NPR-1) financial statements as of, and for the years ended, September 30, 1997 and 1996.
Sukhoruchkin, V.; Yurasov, N.; Goncharenko, Y.; Mullen, M.; McConnell, D.
1996-12-31
In March 1995, the Russian Navy contacted safeguards experts at the Kurchatov Institute (KI) and proposed the initiation of work to enhance nuclear materials protection, control, and accounting (MPC and A) at Russian Navy facilities. Because of KI`s successful experience in laboratory-to-laboratory MPC and A cooperation with US Department of Energy Laboratories, the possibility of US participation in the work with the Russian Navy was explored. Several months later, approval was received from the US Government and the Russian Navy to proceed with this work on a laboratory-to-laboratory basis through Kurchatov Institute. As a first step in the cooperation, a planning meeting occurred at KI in September, 1995. Representatives from the US Department of Energy (DOE), the US Department of Defense (DOD), the Russian Navy, and KI discussed several areas for near-term cooperative work, including a vulnerability assessment workshop and a planning study to identify and prioritize near-term MPC and A enhancements that might be implemented at Russian facilities which store or handle unirradiated highly enriched uranium fuel for naval propulsion applications. In subsequent meetings, these early proposals have been further refined and extended. This MPC and A cooperation will now include enhanced protection and control features for storage facilities and refueling service ships, computerized accounting systems for naval fuel, methods and equipment for rapid inventories, improved security of fresh fuel during truck transportation, and training. This paper describes the current status and future plans for MPC and A cooperation for naval nuclear materials.
1997-07-01
In FY96, Enterprise Advisory Services, Inc. (EASI) continued to support efforts to protect endangered species and cultural resources at the Naval Petroleum Reserves in California (NPRC). These efforts are conducted to ensure NPRC compliance with regulations regarding the protection of listed species and cultural resources on federal properties. Population monitoring activities were conducted for San Joaquin kit foxes, giant kangaroo rats, blunt-nosed leopard lizards, and Hoover`s wooly-star. Kit fox abundance and distribution was assessed by live-trapping over a 329-km{sup 2} area. Kit fox reproduction and mortality were assessed by radiocollaring and monitoring 22 adults and two pups. Reproductive success and litter size were determined through live-trapping and den observations. Rates and sources of kit fox mortality were assessed by recovering dead radiocollared kit foxes and conducting necropsies to determine cause of death. Abundance of coyotes and bobcats, which compete with kit foxes, was determined by conducting scent station surveys. Kit fox diet was assessed through analysis of fecal samples collected from live-trapped foxes. Abundance of potential prey for kit foxes was determined by conducting transect surveys for lagornorphs and live-trapping small mammals.
Naval Petroleum Reserves in California site environmental report for calendar year 1989
Not Available
1989-01-01
This summary for Naval Petroleum Reserves in California (NPRC) is divided into NPR-1 and NPR-2. Monitoring efforts at NPR-1 include handling and disposal of oilfield wastes; environmental preactivity surveys for the protection of endangered species and archaeological resources; inspections of topsoil stockpiling; monitoring of revegetated sites; surveillance of production facilities for hydrocarbons and oxides of nitrogen (NO{sub x}) emissions; monitoring of oil spill prevention and cleanup; and monitoring of wastewater injection. No major compliance issues existed for NPR-1 during 1989. Oil spills are recorded, reviewed for corrective action, and reported. Environmental preactivity surveys for proposed projects which may disturb or contaminate the land are conducted to prevent damage to the federally protected San Joaquin kit fox, blunt-nosed leopard lizard, Tipton kangaroo rat and the giant kangaroo rat. Projects are adjusted or relocated as necessary to avoid impact to dens, burrows, or flat-bottomed drainages. A major revegetation program was accomplished in 1989 for erosion control enhancement of endangered species habitat. The main compliance issue on NPR-2 was oil and produced water discharges into drainages by lessees. An additional compliance issue on NPR-2 is surface refuse from past oilfield operations. 17 refs.
Memory, S.B.
1991-12-01
An evaluation has been made of two different techniques which could prove valuable for Naval refrigeration needs in the future. The first is electrohydrodynamic (EHD) enhancement of pool boiling and condensation heat transfer; this has been shown to provide significant enhancements for both modes of heat transfer under certain conditions and could provide increases in efficiency of present vapor-compression systems. EHD techniques are quite advanced and prototype condenser and evaporator bundles are currently being tested. The second technique is an alternative refrigeration technology called thermoacoustic refrigeration; alternative technologies have become increasingly attractive over recent years due to environmental concerns over CFCs. Thermoacoustic refrigeration uses acoustic power to pump heat from a low temperature source to a high temperature sink. It is still in the early stages of development and can presently accommodate only small thermal loads. However, its general principles of operation have been proven and its resent capacity and efficiency limitations are not seen as a problem in the long term. Electrohydrodynamic Enhancement, Boiling and Condensation, Thermoacoustic Refrigeration.
Schey, Stephen; Francfort, Jim
2015-06-01
Several U.S. Department of Defense base studies have been conducted to identify potential U.S. Department of Defense transportation systems that are strong candidates for introduction or expansion of plug-in electric vehicles (PEVs). This study is focused on the Naval Air Station Whidbey Island (NASWI) located in Washington State. Task 1 consisted of a survey of the non-tactical fleet of vehicles at NASWI to begin the review of vehicle mission assignments and types of vehicles in service. In Task 2, daily operational characteristics of vehicles were identified to select vehicles for further monitoring and attachment of data loggers. Task 3 recorded vehicle movements in order to characterize the vehicles’ missions. The results of the data analysis and observations were provided. Individual observations of the selected vehicles provided the basis for recommendations related to PEV adoption, i.e., whether a battery electric vehicle (BEV) or plug-in hybrid electric vehicle (PHEV) (collectively PEVs) can fulfill the mission requirements. It also provided the basis for recommendations related to placement of PEV charging infrastructure. This report focuses on an implementation plan for the near-term adoption of PEVs into the NASWI fleet.
Limiting factors to advancing thermal-battery technology for naval applications
Davis, P.B.; Winchester, C.S.
1991-10-01
Thermal batteries are primary reserve electrochemical power sources using molten salt electrolyte which experience little effective aging while in storage or dormant deployment. Thermal batteries are primarily used in military applications, and are currently used in a wide variety of Navy devices such as missiles, torpedoes, decays, and training targets, usually as power supplies in guidance, propulsion, and Safe/Arm applications. Technology developments have increased the available energy and power density ratings by an order of magnitude in the last ten years. Present thermal batteries, using lithium anodes and metal sulfide cathodes, are capable of performing applications where only less rugged and more expensive silver oxide/zinc or silver/magnesium chloride seawater batteries could serve previously. Additionally, these batteries are capable of supplanting lithium/thionyl chloride reserve batteries in a variety of specifically optimized designs. Increases in thermal battery energy and power density capabilities are not projected to continue with the current available technology. Several battery designs are now at the edge of feasibility and safety. Since future naval systems are likely to require continued growth of battery energy and Power densities, there must be significant advances in battery technology. Specifically, anode alloy composition and new cathode materials must be investigated to allow for safe development and deployment of these high power, higher energy density batteries.
Conservation plan for protected species on Naval Petroleum Reserve No. 1, Kern County, California
Otten, M.R.M.; Cypher, B.L.
1997-07-01
Habitats in and around Naval Petroleum Reserve No. 1 (NPR-1) support populations of various vertebrates and plants, including a number of threatened and endangered species. Adequate conservation of habitats and species, particularly protected species, can be facilitated through development and implementation of management plans. This document provides a comprehensive plan for the conservation of protected species on NPR-1, through compliance with terms and conditions expressed in Biological Opinions rendered by the U.S. Fish and Wildlife Service for NPR-1 activities. Six conservation strategies by which threatened and endangered species have been, and will be, protected are described: population monitoring, mitigation strategies, special studies, operating guidelines and policies, information transfer and outreach, and the endangered species conservation area. Population monitoring programs are essential for determining population densities and for assessing the effects of oil field developments and environmental factors on protected species. Mitigation strategies (preactivity surveys and habitat reclamation) are employed to minimize the loss of important habitats components and to restore previously disturbed lands to conditions more suitable for species` use. A number of special studies were undertaken between 1985 and 1995 to investigate the effectiveness of a variety of population and habitat management techniques with the goal of increasing the density of protected species. Operating guidelines and policies governing routine oil field activities continue to be implemented to minimize the potential for the incidental take of protected species and minimize damage to wildlife habitats. Information transfer and outreach activities are important means by which technical and nontechnical information concerning protected species conservation on NPR-1 is shared with both the scientific and non-scientific public.
1996-04-01
In FY95, EG and G Energy Measurements, Inc. (EG and G/EM) continued to support efforts to protect endangered species and cultural resources at the Naval Petroleum Reserves in California (NPRC). These efforts are conducted to ensure NPRC compliance with regulations regarding the protection of listed species and cultural resources on Federal properties. Population monitoring activities are conducted annually for San Joaquin kit foxes, giant kangaroo rats, blunt-nosed leopard lizards, and Hoover`s wooly-star. To mitigate impacts of oil field activities on listed species, 674 preactivity surveys covering approximately 211 hectares (521 acres) were conducted in FY95. EG and G/EM also assisted with mitigating effects from third-party projects, primarily by conducting biological and cultural resource consultations with regulatory agencies. EG and G/EM has conducted an applied habitat reclamation program at NPRC since 1985. In FY95, an evaluation of revegetation rates on reclaimed and non-reclaimed disturbed lands was completed, and the results will be used to direct future habitat reclamation efforts at NPRC. In FY95, reclamation success was monitored on 50 sites reclaimed in 1985. An investigation of factors influencing the distribution and abundance of kit foxes at NPRC was initiated in FY94. Factors being examined include habitat disturbance, topography, grazing, coyote abundance, lagomorph abundance, and shrub density. This investigation continued in FY95 and a manuscript on this topic will be completed in FY96. Also, Eg and G/EM completed collection of field data to evaluate the effects of a well blow-out on plant and animal populations. A final report will be prepared in FY96. Finally, EG and G/EM completed a life table analysis on San Joaquin kit foxes at NPRC.
Use of microbes for paraffin cleanup at Naval Petroleum Reserve No. 3
Giangiacomo, L.; Khatib, A.
1995-12-31
Naval Petroleum Reserve No. 3 (NPR-3), also known as Teapot Dome, is a government-owned oil field in Natrona County, Wyoming. It is an asymmetrical anticline located on the western edge of the Powder River Basin, just south of the Salt Creek Anticline. Production started in 1922, and today the field is a marginally economic stripper field with average production of less than 3 BOPD (0.5 m{sup 3}/D) per well. Total field production is about 1,800 BOPD (286 m{sup 3}/D). The Second Wall Creek Formation was waterflooded from 1979 until June 1992 with poor results due to the extensive natural fracture system in this sandstone unit. Since water injection ceased, reservoir pressure has declined to very low levels. Liquids extraction and reinjection of the gas produced from high-GOR wells along the gas-oil contact continues, but the average gas cap pressure has fallen to approximately 150 psi (1.03 MPa) from an original pressure of 1,120 psi (7.72 MPa). Since the oil is highly paraffinic, wax deposition in the hydraulic fractures and the perforations has become a serious production problem. Microbial treatment was considered as a possible low-cost solution. Four wells were selected in the Second Wall Creek Reservoir with severe paraffin problems and production rates high enough to economically justify the treatment. Problems were experienced with the production of thick oil after approximately three months. This was interpreted to be a result of previously immobile paraffin being cleaned up. A slight decrease in the decline rate was seen in the wells, although some external factors cloud the interpretation. Microbial treatments were discontinued because of marginal economics. Three of the four wells produced additional oil and had a positive incremental cash flow. Oil viscosity tests did indicate that some positive microbial thinning was occurring, and changes to the treatment procedure may potentially yield more economic results in the future.
Report of endangered species studies on Naval Petroleum Reserve No. 2, Kern County, California
O'Farrell, T.P.; Warrick, G.D.; Mathews, N.E.; Kato, T.T.
1987-09-01
Between 1983 and 1986 the size of the population of San Joaquin kit foxes (Vulpes macrotis mutica) on Naval Petroleum Reserve No. 2 (NPR-2), Kern County, California, was estimated semiannually using capture-recapture techniques. Although summer population estimates varied between 222 in 1983 and 121 in 1986, and winter estimates varies between 258 in 1984 and 91 in 1983, the population appeared to remain relatively stable at an apparent norm of 165. Kit foxes were abundant even in the intensely developed areas, and numbers and densities (1.12 to 2.49/sq mile) were consistently higher on NPR-2 than on neighboring NPR-1. The percentage of adult vixens that successfully raised pups was 55%, average litter size was 4.0 +- 0.0, and the sex ratio (M:F) of 25 pups was 1:1.5. Most (45.2%) foxes were killed by coyotes (Canis latrans), vehicles killed 6.4%, and 6.5% died of other causes. A cause could not be determined for 41.9% of the deaths. There was a general increase in coyote visitation rates at scent stations, but kit fox visitation rates generally decreased. Kit fox indices were consistently higher on NPR-2 than on NPR-1. Approximately 15% of the kit foxes on NPR-2 dispersed an average of 2.2 +- 0.2 miles. Average dispersal distance did not differ between the sexes. The longest dispersal was 6.9 miles. Proportionately more male than female pups dispersed. Remains of lagomorphs (jackrabbits and cottontails) and kangaroo rats had the highest frequency of occurrence in scats. Frequency of occurrence of lagomorph remains was greater in developed than in undeveloped habitats. Proportions of lagomorph remains increased and kangaroo rat remains decreased between 1983 and 1984. 62 refs., 9 figs., 24 tabs.
Not Available
1994-06-01
Volume 1 to the Department of Energy`s Programmatic Spent Nuclear Fuel Management and Idaho National Engineering Laboratory Environmental Management Programs Environmental Impact Statement evaluates a range of alternatives for managing naval spent nuclear fuel expected to be removed from US Navy nuclear-powered vessels and prototype reactors through the year 2035. The Environmental Impact Statement (EIS) considers a range of alternatives for examining and storing naval spent nuclear fuel, including alternatives that terminate examination and involve storage close to the refueling or defueling site. The EIS covers the potential environmental impacts of each alternative, as well as cost impacts and impacts to the Naval Nuclear Propulsion Program mission. This Appendix covers aspects of the alternatives that involve managing naval spent nuclear fuel at four naval shipyards and the Naval Nuclear Propulsion Program Kesselring Site in West Milton, New York. This Appendix also covers the impacts of alternatives that involve examining naval spent nuclear fuel at the Expended Core Facility in Idaho and the potential impacts of constructing and operating an inspection facility at any of the Department of Energy (DOE) facilities considered in the EIS. This Appendix also considers the impacts of the alternative involving limited spent nuclear fuel examinations at Puget Sound Naval Shipyard. This Appendix does not address the impacts associated with storing naval spent nuclear fuel after it has been inspected and transferred to DOE facilities. These impacts are addressed in separate appendices for each DOE site.
Hillesheim, M.; Mosey, G.
2014-11-01
The U.S. Environmental Protection Agency (EPA) Office of Solid Waste and Emergency Response, in accordance with the RE-Powering America's Lands initiative, engaged the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) to conduct feasibility studies to assess the viability of developing renewable energy generating facilities on contaminated sites. Portsmouth Naval Shipyard (PNSY) is a United States Navy facility located on a series of conjoined islands in the Piscataqua River between Kittery, ME and Portsmouth, NH. EPA engaged NREL to conduct a study to determine technical feasibility of deploying ground-source heat pump systems to help PNSY achieve energy reduction goals.
U.S. Department of Energy (DOE) all webpages (Extended Search)
Direct Numerical Simulation - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Energy Defense Waste Management Programs Advanced
Walker, J.F. Jr.; Villiers-Fisher, J.F.; Brown, C.H. Jr.
1987-01-01
Oak Ridge National Laboratory (ORNL) was contracted by the Naval Energy and Environmental Support Activity (NEESA) to analyze the wastewater problems at a Naval Ordnance Station (NOS) plating shop in the eastern United States to recommend innovative wastewater treatment technologies for handling those problems and to implement the recommended treatment technology. Hexavalent chromium was identified as the major problem area at NOS. Water conservation measures were recommended which would reduce the volume of chromium-contaminated wastewater from approximately 300 L/min to approximately 20 L/min. A treatment scheme consisting of RO followed by evaporation of the RO concentrate steam was recommended. Paint-stripping operations at NOS potentially contaminate the wastewater with phenol, trichloroethane, and possibly other organics. However, the need for a treatment unit for removal of organics could not be established due to a lack of organic analytical data. A characterization study was therefore recommended for the NOS plating shop. If treatment for organics is necessary, the treatment unit might include two-stage filtration for removal of paint flakes or other solids, air stripping for removal of volatile organics, and carbon adsorption for removal of residual organics. 7 refs., 6 figs., 3 tabs.
Spadafora, S.J.; Hegedus, C.R.; Clark, K.J.; Eng, A.T.; Pulley, D.F.
1992-06-24
With the recent increase in awareness about the environment, there is an expanding concern of the deleterious effects of current materials and processes. Federal, state and local environmental agencies such as the EPA, State Air Resource Boards and local Air Quality Management Districts (AQMD) have issued legislation that restrict or prohibit the use and disposal of hazardous materials. National and local laws like the Clean Air and Clean Water Acts, Resource Conservation and Recovery Act, and AQMD regulations are examples of rules that govern the handling and disposal of hazardous materials and waste. The Department of Defense (DoD), in support of this effort, has identified the major generators of hazardous materials and hazardous waste to be maintenance depots and operations, particularly cleaning, pretreating, plating, painting and paint removal processes. Reductions of waste in these areas has been targeted as a primary goal in the DOD. The Navy is committed to significantly reducing its current hazardous waste generation and is working to attain a near zero discharge of hazardous waste by the year 2000. In order to attain these goals, the Naval Air Warfare Center Aircraft Division at Warminster has organized and is carrying out a comprehensive program in cooperation with the Naval Air Systems Command, the Air Force and the Department of Energy that deal with the elimination or reduction of hazardous materials. .... Environmental materials, Organic coatings, Inorganic pretreatments, Paint removal techniques, Cleaners, CFC'S.
Not Available
1994-09-30
Naval Station Treasure Island, Hunters Point Annex (HPA), an inactive Naval shipyard located on a peninsula in the San Francisco Bay, San Francisco, California, was listed for base closure in 1990. Metals, pesticides, radium-226, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds, semivolatile organic compounds, petroleum products, and asbestos have been found in various media such as soil, groundwater, surface water, air, and sediments. Navy contractors have identified 58 HPA areas where there may be contamination; investigations at these areas are ongoing.
Confidence in Numerical Simulations
Hemez, Francois M.
2015-02-23
This PowerPoint presentation offers a high-level discussion of uncertainty, confidence and credibility in scientific Modeling and Simulation (M&S). It begins by briefly evoking M&S trends in computational physics and engineering. The first thrust of the discussion is to emphasize that the role of M&S in decision-making is either to support reasoning by similarity or to “forecast,” that is, make predictions about the future or extrapolate to settings or environments that cannot be tested experimentally. The second thrust is to explain that M&S-aided decision-making is an exercise in uncertainty management. The three broad classes of uncertainty in computational physics and engineering are variability and randomness, numerical uncertainty and model-form uncertainty. The last part of the discussion addresses how scientists “think.” This thought process parallels the scientific method where by a hypothesis is formulated, often accompanied by simplifying assumptions, then, physical experiments and numerical simulations are performed to confirm or reject the hypothesis. “Confidence” derives, not just from the levels of training and experience of analysts, but also from the rigor with which these assessments are performed, documented and peer-reviewed.
Rythmos Numerical Integration Package
Energy Science and Technology Software Center (OSTI)
2006-09-01
Rythmos numerically integrates transient differential equations. The differential equations can be explicit or implicit ordinary differential equations ofr formulated as fully implicit differential-algebraic equations. Methods include backward Euler, forward Euler, explicit Runge-Kutta, and implicit BDF at this time. Native support for operator split methods and strict modularity are strong design goals. Forward sensitivity computations will be included in the first release with adjoint sensitivities coming in the near future. Rythmos heavily relies on Thyra formore » linear algebra and nonlinear solver interfaces to AztecOO, Amesos, IFPack, and NOX in Tilinos. Rythmos is specially suited for stiff differential equations and thos applictions where operator split methods have a big advantage, e.g. Computational fluid dynamics, convection-diffusion equations, etc.« less
1996-02-15
This report presents the results of the independent certified public accountant`s audit of the Department of Energy`s (Department) Naval Petroleum and Oil Shale Reserves (NPOSR) financial statements as of September 30, 1995. The auditors have expressed an unqualified opinion on the 1995 statements. Their reports on the NPOSR internal control structure and compliance with laws and regulations are also provided.
The U.S. Department of Energy developed this EIS to assess the potential environmental impacts of the continued operation of the Naval Petroleum Reserve No. 1 at the Maximum Efficient Rate authorized by Public Law 94-258. This EIS supplements DOE/EIS-0012.
Armstrong, P.R.; Schmelzer, J.R.
1997-01-01
DOE`s Federal Energy Management Program supports efforts to reduce energy use and associated expenditures within the federal sector; one such effort, the New Technology Demonstration Program (NTDP)(formerly the Test Bed Demonstration program), seeks to evaluate new energy saving US technologies and secure their more timely adoption by the federal government. This report describes the field evaluation conducted to examine the performance of a 15-ton natural-gas-engine- driven, split-system, air-conditioning unit. The unit was installed at a multiple-use building at Willow Grove Naval Air Station, a regular and reserve training facility north of Philadelphia, and its performance was monitored under the NTDP.
Armstrong, P.R.; Conover, D.R.
1993-05-01
In a field evaluation conducted for the US Department of Energy (DOE) Office of Federal Energy Management Program (FEMP), the Pacific Northwest Laboratory (PNL) examined the performance of a new US energy-related technology under the FEMP Test Bed Demonstration Program. The technology was a 15-ton natural gas engine driven roof top air conditioning unit. Two such units were installed on a naval retail building to provide space conditioning to the building. Under the Test Bed Demonstration Program, private and public sector interests are focused to support the installation and evaluation of new US technologies in the federal sector. Participating in this effort under a Cooperative Research and Development Agreement (CRADA) with DOE were the American Gas Cooling Center, Philadelphia Electric Company, Thermo King Corporation, and the US Naval Air Station at Willow Grove, Pennsylvania. Equipment operating and service data as well as building interior and exterior conditions were secured for the 1992 cooling season. Based on a computer assessment of the building using standard weather data, a comparison was made with the energy and operating costs associated with the previous space conditioning system. Based on performance during the 1992 cooling season and adjusted to a normal weather year, the technology will save the site $6,000/yr in purchased energy costs. An additional $9,000 in savings due to electricity demand ratchet charge reductions will also be realized. Detailed information on the technology, the installation, and the results of the technology test are provided to illustrate the advantages to the federal sector of using this technology. A history of the CRADA development process is also reported.
This EA evaluates the environmental impacts of the proposal to install an overhead powerline extension from the U.S. Department of Energy's Naval Petroleum Reserve No. 1 (NPR-1) power source to the...
This report documents the Naval Reactors investigation into the collapse ofa partially-erected spent fuel storage building, Overpack Storage Expansion #2 (OSE2), at the Naval Reactors Facility. The Accident Investigation Board inspected the scene, collected physical and photographic evidence, interviewed involved personnel, and reviewed relevant documents to determine the key causes of the accident. Based on the information gathered during the investigation, the Board identified several engineering and safety deficiencies that need to be addressed to prevent recurrence.
Not Available
1991-08-01
As a result of US Department of Energy (DOE) monitoring activities, it was determined in 1983 that the potential existed for natural gas resources underlying the Naval Oil Shales Reserves Nos. 1 and 3 (NOSrs-1 3) to be drained by privately-owned gas wells that were being drilled along the Reserves borders. In 1985, DOE initiated a limited number of projects to protect the Government's interest in the gas resources by drilling its own offset production'' wells just inside the boundaries, and by formally sharing in the production, revenues and costs of private wells that are drilled near the boundaries ( communitize'' the privately-drilled wells). The scope of these protection efforts must be expanded. DOE is therefore proposing a Natural Gas Protection Program for NOSRs-1 3 which would be implemented over a five-year period that would encompass a total of 200 wells (including the wells drilled and/or communitized since 1985). Of these, 111 would be offset wells drilled by DOE on Government land inside the NOSRs' boundaries and would be owned either entirely by the Government or communitized with adjacent private land owners or lessees. The remainder would be wells drilled by private operators in an area one half-mile wide extending around the NOSRs boundaries and communitized with the Government. 23 refs., 2 figs., 6 tabs.
Not Available
1990-09-28
The 82.6-acre Naval Industrial Reserve Ordnance Plant (NIROP) site is a weapons system manufacturing facility in Fridley, Minnesota, which began operations in 1940. The site is a government-owned, contractor-operated, plant located just north of the FMC Corp. During the 1970s, paint sludge and chlorinated solvents were disposed of onsite in pits and trenches. In 1981, State investigations identified TCE in onsite water supply wells drawing from the Prairie DuChien/Jordan aquifer, and the wells were shut down. In 1983, EPA found drummed waste in the trenches or pits at the northern portion of the site, and as a result, during 1983 and 1984, the Navy authorized an installation restoration program, during which approximately 1,200 cubic yards of contaminated soil and 42 drums were excavated and landfilled offsite. The Record of Decision (ROD) addresses the remediation of a shallow ground water operable unit. The primary contaminants of concern affecting the ground water are VOCs including PCE, TCE, toluene, and xylene.
Rohrer, W.L.; Vita, C.L.; Schrock, W.; Leicht, G.
1996-12-31
Dredge spoils, industrial fill, and liquid wastes from the 1940s to 1970s have resulted in inorganic and organic contamination of soils, groundwater, and marine sediments near the U.S.S. Missouri and Charleston Beach parking lots at Puget Sound Naval Shipyard (PSNS), in Bremerton, Washington. Extensive collection of environmental data from several studies including the recently completed Remedial Investigation conducted under CERCLA have confirmed contaminant levels above federal risk screening levels and state regulatory criteria for several heavy metals and organic compounds, including pesticides and PCBs. Although the correlation between contamination in marine sediments and those in on-shore fill appears to be strong, there is little evidence that a viable transport pathway currently exists from soils to groundwater and thence to sediments. Several methods used to estimate chemical mass flux from soil to groundwater to sediments and marine waters of Sinclair Inlet are corroborative in this regard. Nonetheless, this result is vexing because present groundwater concentrations exceed ARARs, yet are below levels of concern in terms of mass flux to marine waters. Despite the marginal risks posed by groundwater, various remedial alternatives, including perimeter containment using a subsurface waste-stabilized containment wall, were evaluated to determine whether chemical flux could be reduced to levels below those observed at the present time. Three-dimensional flow modelling and transport modelling also confirmed that chemical fluxes were limited in magnitude and could be addressed with more conventional remedial approaches.
Llopis, J.L.; Sjostrom, K.J.; Murphy, W.L.
1997-06-01
A geophysical investigation was conducted at the Mustard Gas Burial Ground (MGBG) at the Naval Surface Warfare Center, Crane Division, Crane, IN. The MGBG, an approximately 2-acre area, is a former Solid Waste Management Unit. The objective of the investigation was to detect and delineate anomalies indicating the locations of buried structures, objects, or disturbed zones associated with past hazardous waste burial at the MGBG. The locations of these objects are needed so they can be excavated for removal to a permanent treatment or disposal site. Frequency and time domain electromagnetic (EM) along with magnetic survey methods were used at the MGBG. All the surveys performed at the MGBG indicated an anomalous area approximately 10 ft in diameter centered on Station 255 on Line 130. The estimated depth of the anomaly, based on results of the transient EM surveys, is 1 to 2 ft. The anomaly is presumed to be ferrous in nature since it was detected by the magnetometer. An additional, 2- to 3-ft diameter anomaly, caused by a small metallic object was detected by the transient EM surveys.
Milliken, M.D.; McJannet, G.S.; Shiflett, D.W.; Deutsch, H.A.
1996-12-31
The {open_quotes}A{close_quotes} sands of the Northwest Stevens Pool consist of six major subdivisions (A1-A6) and numerous sublayers. These sands are above the {open_quotes}N Point{close_quotes} stratigraphic marker, making them much younger than most other Stevens sands at Elk Hills. Cores show the A1-A3 sands to be possibly mass transport deposition, primarily debris flows, slumps, and sand injection bodies. The A4-A6 sands are characterized by normally graded sheet-like sand bodies Hospital of traditional outer fan turbidite lithofacies. Most current production from the A1-A2 interval comes from well 373A-7R, are completed waterflood wells that came on line in 1992 at 1400 BOPD. Well 373A-7R is an anomaly in the A1-A2 zone, where average production from the other ten wells is 200 BOPD. Other evidence for compartmentalization in the A1-A2 interval includes sporadic oil-water contacts and drawdown pressures, difficult log correlations, and rapid thickness changes. In 1973, well 362-7R penetrated 220 ft of wet Al sand. The well was redrilled updip and successfully completed in the A1, where the oil-water contact is more than 130 ft lower than the original hole and faulting is not apparent. In 1992, horizontal well 323H-7R unexpectedly encountered an entirely wet Al wedge zone. Reevaluation of the A1-A3 and other sands as mass transport origin is important for modeling initialization and production/development strategies.
Milliken, M.D.; McJannet, G.S. ); Shiflett, D.W. ); Deutsch, H.A. )
1996-01-01
The [open quotes]A[close quotes] sands of the Northwest Stevens Pool consist of six major subdivisions (A1-A6) and numerous sublayers. These sands are above the [open quotes]N Point[close quotes] stratigraphic marker, making them much younger than most other Stevens sands at Elk Hills. Cores show the A1-A3 sands to be possibly mass transport deposition, primarily debris flows, slumps, and sand injection bodies. The A4-A6 sands are characterized by normally graded sheet-like sand bodies Hospital of traditional outer fan turbidite lithofacies. Most current production from the A1-A2 interval comes from well 373A-7R, are completed waterflood wells that came on line in 1992 at 1400 BOPD. Well 373A-7R is an anomaly in the A1-A2 zone, where average production from the other ten wells is 200 BOPD. Other evidence for compartmentalization in the A1-A2 interval includes sporadic oil-water contacts and drawdown pressures, difficult log correlations, and rapid thickness changes. In 1973, well 362-7R penetrated 220 ft of wet Al sand. The well was redrilled updip and successfully completed in the A1, where the oil-water contact is more than 130 ft lower than the original hole and faulting is not apparent. In 1992, horizontal well 323H-7R unexpectedly encountered an entirely wet Al wedge zone. Reevaluation of the A1-A3 and other sands as mass transport origin is important for modeling initialization and production/development strategies.
U.S. Department of Energy (DOE) all webpages (Extended Search)
... saturation mechanism depends sensitively on the viscosity parameterized by Pm. ... A more thorough treatment of the dynamic variation of dominant eigenmodes can be found for ...
1996-05-01
The Department of Energy (DOE), in conjunction with the Bureau of Land Management (BLM), has prepared an Environmental Assessment (DOE/EA-1124) to identify and evaluate the potential environmental impacts of the proposed geophysical seismic survey on and adjacent to the Naval Petroleum Reserve No.1 (NPR-1), located approximately 35 miles west of Bakersfield, California. NPR-1 is jointly owned and operated by the federal government and Chevron U.S.A. Production Company. The federal government owns about 78 percent of NPR-1, while Chevron owns the remaining 22 percent. The government`s interest is under the jurisdiction of DOE, which has contracted with Bechtel Petroleum Operations, Inc. (BPOI) for the operation and management of the reserve. The 3-dimensional seismic survey would take place on NPR-1 lands and on public and private lands adjacent to NPR-1. This project would involve lands owned by BLM, California Department of Fish and Game (CDFG), California Energy Commission (CEC), The Nature Conservancy, the Center for Natural Lands Management, oil companies (Chevron, Texaco, and Mobil), and several private individuals. The proposed action is designed to provide seismic data for the analysis of the subsurface geology extant in western NPR-1 with the goal of better defining the commercial limits of a currently producing reservoir (Northwest Stevens) and three prospective hydrocarbon bearing zones: the {open_quotes}A Fan{close_quotes} in Section 7R, the 19R Structure in Section 19R, and the 13Z Structure in Section 13Z. Interpreting the data is expected to provide NPR-1 owners with more accurate locations of structural highs, faults, and pinchouts to maximize the recovery of the available hydrocarbon resources in western NPR-1. Completion of this project is expected to increase NPR-1 recoverable reserves, and reduce the risks and costs associated with further exploration and development in the area.
Radio-optical reference frame link using the U.S. Naval observatory astrograph and deep CCD imaging
Zacharias, N.; Zacharias, M. I.
2014-05-01
Between 1997 and 2004 several observing runs were conducted, mainly with the CTIO 0.9 m, to image International Celestial Reference Frame (ICRF) counterparts (mostly QSOs) in order to determine accurate optical positions. Contemporary to these deep CCD images, the same fields were observed with the U.S. Naval Observatory astrograph in the same bandpass. They provide accurate positions on the Hipparcos/Tycho-2 system for stars in the 10-16 mag range used as reference stars for the deep CCD imaging data. Here we present final optical position results of 413 sources based on reference stars obtained by dedicated astrograph observations that were reduced following two different procedures. These optical positions are compared to radio very long baseline interferometry positions. The current optical system is not perfectly aligned to the ICRF radio system with rigid body rotation angles of 3-5 mas (= 3σ level) found between them for all three axes. Furthermore, statistically, the optical-radio position differences are found to exceed the total, combined, known errors in the observations. Systematic errors in the optical reference star positions and physical offsets between the centers of optical and radio emissions are both identified as likely causes. A detrimental, astrophysical, random noise component is postulated to be on about the 10 mas level. If confirmed by future observations, this could severely limit the Gaia to ICRF reference frame alignment accuracy to an error of about 0.5 mas per coordinate axis with the current number of sources envisioned to provide the link. A list of 36 ICRF sources without the detection of an optical counterpart to a limiting magnitude of about R = 22 is provided as well.
Stephanie von Numers | Department of Energy
Stephanie von Numers - Communications and Web Coordinator, Education & Workforce Development Stephanie von Numers joined the U.S. Department of Energy's Office of Energy Efficiency ...
Robichaud, R.; Fields, J.; Roberts, J. O.
2012-02-01
The U.S. Environmental Protection Agency (EPA) launched the RE-Powering America's Land initiative to encourage development of renewable energy (RE) on potentially contaminated land and mine sites. EPA is collaborating with the U.S. Department of Energy's (DOE's) National Renewable Energy Laboratory (NREL) to evaluate RE options at Naval Station (NAVSTA) Newport in Newport, Rhode Island where multiple contaminated areas pose a threat to human health and the environment. Designated a superfund site on the National Priorities List in 1989, the base is committed to working toward reducing the its dependency on fossil fuels, decreasing its carbon footprint, and implementing RE projects where feasible. The Naval Facilities Engineering Service Center (NFESC) partnered with NREL in February 2009 to investigate the potential for wind energy generation at a number of Naval and Marine bases on the East Coast. NAVSTA Newport was one of several bases chosen for a detailed, site-specific wind resource investigation. NAVSTA Newport, in conjunction with NREL and NFESC, has been actively engaged in assessing the wind resource through several ongoing efforts. This report focuses on the wind resource assessment, the estimated energy production of wind turbines, and a survey of potential wind turbine options based upon the site-specific wind resource.
Naval electrochemical corrosion reducer
Clark, Howard L.
1991-10-01
A corrosion reducer for use with ships having a hull, a propeller mounted a propeller shaft and extending through the hull, bearings supporting the shaft, at least one thrust bearing and one seal. The improvement includes a current collector and a current reduction assembly for reducing the voltage between the hull and shaft in order to reduce corrosion due to electrolytic action. The current reduction assembly includes an electrical contact, the current collector, and the hull. The current reduction assembly further includes a device for sensing and measuring the voltage between the hull and the shaft and a device for applying a reverse voltage between the hull and the shaft so that the resulting voltage differential is from 0 to 0.05 volts. The current reduction assembly further includes a differential amplifier having a voltage differential between the hull and the shaft. The current reduction assembly further includes an amplifier and a power output circuit receiving signals from the differential amplifier and being supplied by at least one current supply. The current selector includes a brush assembly in contact with a slip ring over the shaft so that its potential may be applied to the differential amplifier.
Not Available
1993-07-01
This document provides an analysis of the potential impacts associated with the proposed action, which is continued operation of Naval Petroleum Reserve No. I (NPR-1) at the Maximum Efficient Rate (MER) as authorized by Public law 94-258, the Naval Petroleum Reserves Production Act of 1976 (Act). The document also provides a similar analysis of alternatives to the proposed action, which also involve continued operations, but under lower development scenarios and lower rates of production. NPR-1 is a large oil and gas field jointly owned and operated by the federal government and Chevron U.SA Inc. (CUSA) pursuant to a Unit Plan Contract that became effective in 1944; the government`s interest is approximately 78% and CUSA`s interest is approximately 22%. The government`s interest is under the jurisdiction of the United States Department of Energy (DOE). The facility is approximately 17,409 acres (74 square miles), and it is located in Kern County, California, about 25 miles southwest of Bakersfield and 100 miles north of Los Angeles in the south central portion of the state. The environmental analysis presented herein is a supplement to the NPR-1 Final Environmental Impact Statement of that was issued by DOE in 1979 (1979 EIS). As such, this document is a Supplemental Environmental Impact Statement (SEIS).
Brandenberger, Jill M.; Metallo, David; Johnston, Robert K.; Gebhardt, Christine; Hsu, Larry
2012-09-01
This interim report summarizes the stormwater monitoring conducted for non-dry dock outfalls in both the confined industrial area and the residential areas of Naval Base Kitsap within the Puget Sound Naval Shipyard (referred to as the Shipyard). This includes the collection, analyses, and descriptive statistics for stormwater sampling conducted from November 2010 through April 2011. Seven stormwater basins within the Shipyard were sampled during at least three storm events to characterize non-dry dock stormwater discharges at selected stormwater drains located within the facility. This serves as the Phase I component of the project and Phase II is planned for the 2011-2012 storm season. These data will assist the Navy, USEPA, Ecology and other stakeholders in understanding the nature and condition of stormwater discharges from the Shipyard and inform the permitting process for new outfall discharges. The data from Phase I was compiled with current stormwater data available from the Shipyard, Sinclair/Dyes Inlet watershed, and Puget Sound in order to support technical investigations for the Draft NPDES permit. The permit would require storm event sampling at selected stormwater drains located within the Shipyard. However, the data must be considered on multiple scales to truly understand potential impairments to beneficial uses within Sinclair and Dyes Inlets.
Disruptive Innovation in Numerical Hydrodynamics
Waltz, Jacob I.
2012-09-06
We propose the research and development of a high-fidelity hydrodynamic algorithm for tetrahedral meshes that will lead to a disruptive innovation in the numerical modeling of Laboratory problems. Our proposed innovation has the potential to reduce turnaround time by orders of magnitude relative to Advanced Simulation and Computing (ASC) codes; reduce simulation setup costs by millions of dollars per year; and effectively leverage Graphics Processing Unit (GPU) and future Exascale computing hardware. If successful, this work will lead to a dramatic leap forward in the Laboratory's quest for a predictive simulation capability.
Numerical computation of Pop plot
Menikoff, Ralph
2015-03-23
The Pop plot — distance-of-run to detonation versus initial shock pressure — is a key characterization of shock initiation in a heterogeneous explosive. Reactive burn models for high explosives (HE) must reproduce the experimental Pop plot to have any chance of accurately predicting shock initiation phenomena. This report describes a methodology for automating the computation of a Pop plot for a specific explosive with a given HE model. Illustrative examples of the computation are shown for PBX 9502 with three burn models (SURF, WSD and Forest Fire) utilizing the xRage code, which is the Eulerian ASC hydrocode at LANL. Comparison of the numerical and experimental Pop plot can be the basis for a validation test or as an aid in calibrating the burn rate of an HE model. Issues with calibration are discussed.
Interagency mechanical operations group numerical systems group
1997-09-01
This report consists of the minutes of the May 20-21, 1971 meeting of the Interagency Mechanical Operations Group (IMOG) Numerical Systems Group. This group looks at issues related to numerical control in the machining industry. Items discussed related to the use of CAD and CAM, EIA standards, data links, and numerical control.
Warrick, G.D.; Kato, T.T.; Phillips, M.V.
1996-12-01
In June 1994, an oil well on Naval Petroleum Reserve No. 1 blew-out and crude oil was deposited downwind. After the well was capped, information was collected to characterize the release and to assess effects to wildlife and plants. Oil residue was found up to 13.7 km from the well site, but deposition was relatively light and the oil quickly dried to form a thin crust on the soil surface. Elevated levels of hydrocarbons were found in livers collected from Heermann`s kangaroo rats (Dipodomys heermanni) from the oiled area but polycyclic aromatic hydrocarbons (known carcinogens or mutagens) were not detected in the livers. Restoration techniques (surface modification and bioremediation) and natural recovery were evaluated within three portions of the oiled area. Herbaceous cover and production, and survival and vigor of desert saltbush (Atriplex polycarpa) were also monitored within each trapping grid.
1996-08-09
The purpose of this report is to present this Consultant`s findings regarding the nature and extent of the mineral estate of the United States at National Petroleum Reserve No. 2 (NPR-2), Buena Vista Hills Field, Kern County, California. Determination of the mineral estate is a necessary prerequisite to this Consultant`s calculation of estimated future cash flows attributable to said estate, which calculations are presented in the accompanying report entitled ``Phase II Final Report, Study of Alternatives for Future Operations of the Naval Petroleum and Oil Shale Reserves, NPR-2, California.`` This Report contains a discussion of the leases in effect at NPR-2 and subsequent contracts affecting such leases. This Report also summarizes discrepancies found between the current royalty calculation procedures utilized at NPR-2 and those procedures required under applicable agreements and regulations. Recommendations for maximizing the government`s income stream at NPR-2 are discussed in the concluding section of this Report.
Armstrong, P.R.; Conover, D.R.
1993-05-01
In a field evaluation conducted for the US Department of Energy (DOE) Office of Federal Energy Management Program (FEMP), the Pacific Northwest Laboratory (PNL) examined the performance of a new US energy-related technology under the FEMP Test Bed Demonstration Program. The technology was a 15-ton natural gas engine driven roof top air conditioning unit. Two such units were installed on a naval retail building to provide space conditioning to the building. Under the Test Bed Demonstration Program, private and public sector interests are focused to support the installation and evaluation of new US technologies in the federal sector. Participating in this effort under a Cooperative Research and Development Agreement (CRADA) with DOE were the American Gas Cooling Center, Philadelphia Electric Company, Thermo King Corporation, and the US Naval Air Station at Willow Grove, Pennsylvania. Equipment operating and service data as well as building interior and exterior conditions were secured for the 1992 cooling season. Based on a computer assessment of the building using standard weather data, a comparison was made with the energy and operating costs associated with the previous space conditioning system. Based on performance during the 1992 cooling season and adjusted to a normal weather year, the technology will save the site $6,000/yr in purchased energy costs. An additional $9,000 in savings due to electricity demand ratchet charge reductions will also be realized. Detailed information on the technology, the installation, and the results of the technology test are provided to illustrate the advantages to the federal sector of using this technology. A history of the CRADA development process is also reported.
numerical modeling | OpenEI Community
Open Energy Information (Open El) [EERE & EIA]
Submitted by Ocop(5) Member 15 July, 2014 - 07:07 MHK LCOE Reporting Guidance Draft Cost Current DOE LCOE numerical modeling Performance Tidal Wave To normalize competing...
Numerical evaluation of effective unsaturated hydraulic properties...
Office of Scientific and Technical Information (OSTI)
unsaturated hydraulic properties for fractured rocks Citation Details In-Document Search Title: Numerical evaluation of effective unsaturated hydraulic properties for ...
1994-12-31
This report presents the results of the independent certified public accountant`s audit of the Department of Energy`s (Department) Naval Petroleum and Oil Shale Reserves (NPOSR) financial statements as of September 30, 1994. The auditors have expressed an unqualified opinion on the 1994 statements. Their reports on the NPOSR internal control structure and on compliance with laws and regulations, and management letter on addressing needed improvements are also provided. NPOSR consists of petroleum reserves in California and Wyoming, and oil shale reserves in Colorado and Utah. The Government`s interests in NPOSR are managed by the Department through its headquarters office in Washington, D.C. In addition, the Department has site offices in both California and Wyoming that are responsible for contractor oversight functions. Daily operations are conducted under contract by two management and operating contractors. By law, NPOSR was authorized to produce crude oil at the maximum efficient rate for six years. The law allowed production to be extended for three year periods, provided that the President of the United States certified that continued maximum production was in the best interest of the nation. The current three year period ends on April 5, 1997. Additional information about NPOSR is provided in the overview and notes to the financial statements.
Cronk, T.A.; Smuin, D.R.; Schlosser, R.M.
1991-09-01
This report addresses subsurface contamination associated with Site 2, the New Fuel Farm at Naval Air Station Fallon (NAS Fallon), Nevada and is an integral part of Phase 2 of the Installation Restoration Program (IR Program) currently underway at the facility. This report: (1) reviews and assesses environmental information characterizing Site 2; (2) determine if site-characterization information is sufficient to design and evaluate removal actions; and, (3) investigates, develops, and describes any removal actions deemed feasible. Previous environmental investigations at Site 2 indicate the presence of floating product (primarily JP-5, jet fuel) on the water table underlying the facility. While the extent of floating-produce plumes has been characterized, the degree of associated soil and groundwater contamination remains uncertain. A comprehensive characterization of soil and groundwater contamination will be completed as the Remedial Investigation/Feasibility Study progresses. Corrective actions are recommended at this time to remove free-phase floating product. Implementing these removal actions will also provide additional information which will be used to direct further investigations of the extent, mobility, and potential environmental threat from soil and groundwater contaminants at this side.
1996-12-01
The US Department of Energy (DOE) has asked Gustavson Associates, Inc. to serve as an Independent Petroleum Consultant under contract DE-AC01-96FE64202. This authorizes a study and recommendations regarding future development of Naval Petroleum Oil Shales Reserves Nos. 1 and 3 (NOSR 1 and 3) in Garfield County, Colorado (Figure 0.1). The report that follows is the Phase II Final Report for that study. Additional details are provided in the Addendum (the Phase 1 Property Description and Fact Finding Report). The key property elements that positively affect the estimated value of NOSR 1 and 3 include the following: working interest income from producing oil and gas leases, income from grazing or leasing of grazing rights, potential income from oil and gas leasing on exploratory (or nonprospective) acreage, potential value of trading surface real estate as ranch land for livestock grazing (56,577 acres). Key elements that negatively impact the estimated value include: environmental assessment costs, gas prices, operating budgets, and lease sale expenses.
1996-12-01
The US Department of Energy (DOE) has asked Gustavson Associates, Inc. to serve as an Independent Petroleum Consultant and authorized a study and recommendations regarding future development of Naval Oil Shale Reserve No. 2 (NOSR-2) in Uintah and Carbon Counties, Utah. The US owns 100% of the mineral rights and about 60% of the surface rights in NOSR-2. The Ute Indian Tribe owns the other 40% of the surface. This 88,890-acre tract was set aside as an oil shale reserve for the US Navy by an Executive Order of President Wilson in 1916. Management of NOSR-2 is the responsibility of DOE. No drilling for oil and gas has occurred on the property and no production has been established. No reserves are present, although the area is hypothesized to overlay gas resources. Mapping by the US Geological Survey and others has resulted in speculative seismic leads for structures that may or may not hold conventional oil and gas. All of the mineral rights (including oil shale) must be considered exploratory and the mineral rights must be valued accordingly. The opinion recommended to maximize value to the US is Option 4, sale of the interest of the US of all or part of NOSR-2. Evaluation of this option results in an estimated value which is more than three times greater than the next highest estimated value, for Option 2, transfer to the Department of the Interior for leasing.
1998-12-01
On October 6, 1997, the Department of Energy (DOE) announced it had agreed to sell all of the Government`s interest in Naval Petroleum Reserve Number 1 (NPR-1) to Occidental Petroleum Corporation for $3.65 billion. This report presents the results of the independent certified public accountants` agreed-upon procedures work on the Preliminary Settlement Statement of the Purchase and Sale Agreement between DOE and Occidental. To fulfill their responsibilities, the Office of Inspector General contracted with the independent public accounting firm of KPMG Peat Marwick LLP to conduct the work for them, subject to their review. The work was done in accordance with the Statements on Standards for Attestation Engagements issued by the American Institute of Certified Public Accountants. As such, the independent certified public accountants performed only work that was agreed upon by DOE and Occidental. This report is intended solely for the use of DOE and Occidental and should not be used by those who have not agreed to the procedures and taken responsibility for the sufficiency of the procedures for their purposes. However, this report is a matter of public record, and its distribution is not limited. The independent certified public accountants identified over 20 adjustments to the Preliminary Settlement Statement that would result in a $10.8 million increase in the sale price.
Direct Numerical Simulation of Compressible, Turbulent Flow ...
U.S. Department of Energy (DOE) all webpages (Extended Search)
The computational mesh for this direct numerical simulation was over 33 billion cells, and was run on up to 102,400 cores under a DoD HPCMP Frontier Project. Nicholas Bisek and ...
1998-04-01
The Secretary of Energy is authorized to produce the Naval Petroleum Reserves No. 3 (NPR-3) at its maximum efficient rate (MER) consistent with sound engineering practices, for a period extending to April 5, 2000 subject to extension. Production at NPR-3 peaked in 1981 and has declined since until it has become a mature stripper field, with the average well yielding less than 2 barrels per day. The Department of Energy (DOE) has decided to discontinue Federal operation of NPR-3 at the end of its life as an economically viable oilfield currently estimated to be 2003. Although changes in oil and gas markets or shifts in national policy could alter the economic limit of NPR-3, it productive life will be determined largely by a small and declining reserve base. DOE is proposing certain activities over the next six years in anticipation of the possible transfer of NPR-3 out of Federal operation. These activities would include the accelerated plugging and abandoning of uneconomic wells, complete reclamation and restoration of abandoned sites including dismantling surface facilities, batteries, roads, test satellites, electrical distribution systems and associated power poles, when they are no longer needed for production, and the continued development of the Rocky Mountain Oilfield Testing Center (RMOTC). DOE has prepared this environmental assessment that analyzes the proposed plugging and abandonment of wells, field restoration and development of RMOTC. Based on the analysis in the EA, the DOE finds that the proposed action is not a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act of 1969 (NEPA). The preparation of an environmental impact statement is not required, and DOE is issuing this Finding of No Significant Impact (FONSI).
Mechanical diode: Comparing numerical and experimental characterizations
Sagartz, M.J.; Segalman, D.; Simmermacher, T.
1998-02-01
In this introductory work, joint compliance is studied in both a numerical and experimental setting. A simple bolted interface is used as the test article and compliance is measured for the joint in both compression and in tension. This simple interface is shown to exhibit a strong non-linearity near the transition from compression to tension (or vice-versa). Modeling issues pertaining to numerically solving for the compliance are addressed. It is shown that the model predictions, in spite of convergence being very sensitive to numerical artifacts of the interface model, are in good agreement with experimentally measured strains and joint compliances. The joint behavior is a mechanical analogy to a diode, i.e., in compression, the joint is very stiff, acting almost as a rigid link, while in tension the joint is relatively soft, acting as a spring.
Numerical simulations of strong incompressible magnetohydrodynamic turbulence
Mason, J.; Cattaneo, F.; Perez, J. C.; Boldyrev, S.
2012-05-15
Magnetised plasma turbulence pervades the universe and is likely to play an important role in a variety of astrophysical settings. Magnetohydrodynamics (MHD) provides the simplest theoretical framework in which phenomenological models for the turbulent dynamics can be built. Numerical simulations of MHD turbulence are widely used to guide and test the theoretical predictions; however, simulating MHD turbulence and accurately measuring its scaling properties is far from straightforward. Computational power limits the calculations to moderate Reynolds numbers and often simplifying assumptions are made in order that a wider range of scales can be accessed. After describing the theoretical predictions and the numerical approaches that are often employed in studying strong incompressible MHD turbulence, we present the findings of a series of high-resolution direct numerical simulations. We discuss the effects that insufficiencies in the computational approach can have on the solution and its physical interpretation.
Numerical prediction of window condensation potential
McGowan, A.G.
1995-08-01
Although a substantial amount of effort has been expended to develop numerical methods for determining windows U-factors (EE 1983; Goss and Curcija 1994; Standaert 1985; CSA 1993a; NFRC 1991), there has been little work to data on using numerical methods to predict condensation potential. It is perhaps of direct interest to most ASHRAE members to determine heat loss and solar gains through windows as a precursor to sizing heating and cooling equipment, but condensation has long been recognized as an extremely important issue for consumers (and, consequently, for window manufacturers). Moreover, building scientists recognize the link between condensation and increased energy consumption (due to latent loads), reduced occupant comfort and indoor air quality (from the presence of bacteria and mold), and structural damage (where accumulated condensation is absorbed by the building material, thus reducing their structural stability). The National Fenestration Rating Council (NFRC) is developing a rating method for condensation potential in fenestration products as part of its mandate from the US Department of Energy (DOE). A rating method would benefit from the use of simulation as a supplement to physical condensation resistance testing to reduce the cost and time required for implementation and increase the flexibility of the rating method. This paper outlines one of the necessary components in the application of numerical methods for evaluating condensation in fenestration products. The theoretical approach and its practical application are discussed, as well as some comparisons between numerical prediction and physical test results for a sample of products.
Numerical likelihood analysis of cosmic ray anisotropies
Carlos Hojvat et al.
2003-07-02
A numerical likelihood approach to the determination of cosmic ray anisotropies is presented which offers many advantages over other approaches. It allows a wide range of statistically meaningful hypotheses to be compared even when full sky coverage is unavailable, can be readily extended in order to include measurement errors, and makes maximum unbiased use of all available information.
Stress-dependent permeability of fractured rock masses: A numerical...
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permeability of fractured rock masses: A numerical study Citation Details In-Document Search Title: Stress-dependent permeability of fractured rock masses: A numerical study We ...
Toward portable programming of numerical linear algebra on manycore...
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Toward portable programming of numerical linear algebra on manycore nodes. Citation Details In-Document Search Title: Toward portable programming of numerical linear algebra on ...
Numerical simulations for low energy nuclear reactions including...
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Numerical simulations for low energy nuclear reactions including direct channels to validate statistical models Citation Details In-Document Search Title: Numerical simulations for ...
Numerical Modeling Studies of The Dissolution-Diffusion-Convection...
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Numerical Modeling Studies of The Dissolution-Diffusion-Convection ProcessDuring CO2 Storage in Saline Aquifers Citation Details In-Document Search Title: Numerical Modeling ...
Error Estimation for Fault Tolerance in Numerical Integration...
U.S. Department of Energy (DOE) all webpages (Extended Search)
Error Estimation for Fault Tolerance in Numerical Integration Solvers Event Sponsor: ... In numerical integration solvers, approximation error can be estimated at a low cost. We ...
Numerical Verification of Bounce Harmonic Resonances in Neoclassical
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for Tokamaks Kimin Kim, Jong-Kyu Park and Allen H. Boozer 70 PLASMA PHYSICS AND FUSION TECHNOLOGY Tokamaks, Numerical Verification Tokamaks, Numerical Verification This...
Development of Numerical Simulation Capabilities for In Situ...
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Development of Numerical Simulation Capabilities for In Situ Heating of Oil Shale Citation Details In-Document Search Title: Development of Numerical Simulation Capabilities for In ...
Numerical modeling of water injection into vapor-dominatedgeothermal...
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Technical Report: Numerical modeling of water injection into vapor-dominatedgeothermal reservoirs Citation Details In-Document Search Title: Numerical modeling of water injection ...
Sandia Energy - Numerical Simulations of Hydrokinetics in the...
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Numerical Simulations of Hydrokinetics in the Roza Canal, Yakima Washington Home Renewable Energy Energy Water Power Computational Modeling & Simulation Numerical Simulations of...
Numerical Modeling At Dixie Valley Geothermal Area (McKenna ...
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Numerical Modeling At Dixie Valley Geothermal Area (McKenna & Blackwell, 2003) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Numerical Modeling...
Numerical recipes for mold filling simulation
Kothe, D.; Juric, D.; Lam, K.; Lally, B.
1998-07-01
Has the ability to simulate the filling of a mold progressed to a point where an appropriate numerical recipe achieves the desired results? If results are defined to be topological robustness, computational efficiency, quantitative accuracy, and predictability, all within a computational domain that faithfully represents complex three-dimensional foundry molds, then the answer unfortunately remains no. Significant interfacial flow algorithm developments have occurred over the last decade, however, that could bring this answer closer to maybe. These developments have been both evolutionary and revolutionary, will continue to transpire for the near future. Might they become useful numerical recipes for mold filling simulations? Quite possibly. Recent progress in algorithms for interface kinematics and dynamics, linear solution methods, computer science issues such as parallelization and object-oriented programming, high resolution Navier-Stokes (NS) solution methods, and unstructured mesh techniques, must all be pursued as possible paths toward higher fidelity mold filling simulations. A detailed exposition of these algorithmic developments is beyond the scope of this paper, hence the authors choose to focus here exclusively on algorithms for interface kinematics. These interface tracking algorithms are designed to model the movement of interfaces relative to a reference frame such as a fixed mesh. Current interface tracking algorithm choices are numerous, so is any one best suited for mold filling simulation? Although a clear winner is not (yet) apparent, pros and cons are given in the following brief, critical review. Highlighted are those outstanding interface tracking algorithm issues the authors feel can hamper the reliable modeling of today`s foundry mold filling processes.
Advanced Numerical Model for Irradiated Concrete
Giorla, Alain B.
2015-03-01
In this report, we establish a numerical model for concrete exposed to irradiation to address these three critical points. The model accounts for creep in the cement paste and its coupling with damage, temperature and relative humidity. The shift in failure mode with the loading rate is also properly represented. The numerical model for creep has been validated and calibrated against different experiments in the literature [Wittmann, 1970, Le Roy, 1995]. Results from a simplified model are shown to showcase the ability of numerical homogenization to simulate irradiation effects in concrete. In future works, the complete model will be applied to the analysis of the irradiation experiments of Elleuch et al. [1972] and Kelly et al. [1969]. This requires a careful examination of the experimental environmental conditions as in both cases certain critical information are missing, including the relative humidity history. A sensitivity analysis will be conducted to provide lower and upper bounds of the concrete expansion under irradiation, and check if the scatter in the simulated results matches the one found in experiments. The numerical and experimental results will be compared in terms of expansion and loss of mechanical stiffness and strength. Both effects should be captured accordingly by the model to validate it. Once the model has been validated on these two experiments, it can be applied to simulate concrete from nuclear power plants. To do so, the materials used in these concrete must be as well characterized as possible. The main parameters required are the mechanical properties of each constituent in the concrete (aggregates, cement paste), namely the elastic modulus, the creep properties, the tensile and compressive strength, the thermal expansion coefficient, and the drying shrinkage. These can be either measured experimentally, estimated from the initial composition in the case of cement paste, or back-calculated from mechanical tests on concrete. If some
Numerical uncertainty in computational engineering and physics
Hemez, Francois M
2009-01-01
Obtaining a solution that approximates ordinary or partial differential equations on a computational mesh or grid does not necessarily mean that the solution is accurate or even 'correct'. Unfortunately assessing the quality of discrete solutions by questioning the role played by spatial and temporal discretizations generally comes as a distant third to test-analysis comparison and model calibration. This publication is contributed to raise awareness of the fact that discrete solutions introduce numerical uncertainty. This uncertainty may, in some cases, overwhelm in complexity and magnitude other sources of uncertainty that include experimental variability, parametric uncertainty and modeling assumptions. The concepts of consistency, convergence and truncation error are overviewed to explain the articulation between the exact solution of continuous equations, the solution of modified equations and discrete solutions computed by a code. The current state-of-the-practice of code and solution verification activities is discussed. An example in the discipline of hydro-dynamics illustrates the significant effect that meshing can have on the quality of code predictions. A simple method is proposed to derive bounds of solution uncertainty in cases where the exact solution of the continuous equations, or its modified equations, is unknown. It is argued that numerical uncertainty originating from mesh discretization should always be quantified and accounted for in the overall uncertainty 'budget' that supports decision-making for applications in computational physics and engineering.
RELAP-7 Numerical Stabilization: Entropy Viscosity Method
R. A. Berry; M. O. Delchini; J. Ragusa
2014-06-01
The RELAP-7 code is the next generation nuclear reactor system safety analysis code being developed at the Idaho National Laboratory (INL). The code is based on the INL's modern scientific software development framework, MOOSE (Multi-Physics Object Oriented Simulation Environment). The overall design goal of RELAP-7 is to take advantage of the previous thirty years of advancements in computer architecture, software design, numerical integration methods, and physical models. The end result will be a reactor systems analysis capability that retains and improves upon RELAP5's capability and extends the analysis capability for all reactor system simulation scenarios. RELAP-7 utilizes a single phase and a novel seven-equation two-phase flow models as described in the RELAP-7 Theory Manual (INL/EXT-14-31366). The basic equation systems are hyperbolic, which generally require some type of stabilization (or artificial viscosity) to capture nonlinear discontinuities and to suppress advection-caused oscillations. This report documents one of the available options for this stabilization in RELAP-7 -- a new and novel approach known as the entropy viscosity method. Because the code is an ongoing development effort in which the physical sub models, numerics, and coding are evolving, so too must the specific details of the entropy viscosity stabilization method. Here the fundamentals of the method in their current state are presented.
A survey of numerical cubature over triangles
Lyness, J.N.; Cools, R.
1993-12-31
This survey collects together theoretical results in the area of numerical cubature over triangles and is a vehicle for a current bibliography. We treat first the theory relating to regular integrands and then the corresponding theory for singular integrands with emphasis on the ``full comer singularity.`` Within these two sections we treat successively approaches based on transforming the triangle into a square, formulas based on polynomial moment fitting, and extrapolation techniques. Within each category we quote key theoretical results without proof, and relate other results and references to these. Nearly all the references we have found may be readily placed in one of these categories. This survey is theoretical in character and does not include recent work in adaptive and automatic integration.
Numerical Studies of Impurities in Fusion Plasmas
DOE R&D Accomplishments [OSTI]
Hulse, R. A.
1982-09-01
The coupled partial differential equations used to describe the behavior of impurity ions in magnetically confined controlled fusion plasmas require numerical solution for cases of practical interest. Computer codes developed for impurity modeling at the Princeton Plasma Physics Laboratory are used as examples of the types of codes employed for this purpose. These codes solve for the impurity ionization state densities and associated radiation rates using atomic physics appropriate for these low-density, high-temperature plasmas. The simpler codes solve local equations in zero spatial dimensions while more complex cases require codes which explicitly include transport of the impurity ions simultaneously with the atomic processes of ionization and recombination. Typical applications are discussed and computational results are presented for selected cases of interest.
High numerical aperture multilayer Laue lenses
Morgan, Andrew J.; Prasciolu, Mauro; Andrejczuk, Andrzej; Krzywinski, Jacek; Meents, Alke; Pennicard, David; Graafsma, Heinz; Barty, Anton; Bean, Richard J.; Barthelmess, Miriam; Oberthuer, Dominik; Yefanov, Oleksandr; Aquila, Andrew; Chapman, Henry N.; Bajt, Saša
2015-06-01
The ever-increasing brightness of synchrotron radiation sources demands improved X-ray optics to utilise their capability for imaging and probing biological cells, nanodevices, and functional matter on the nanometer scale with chemical sensitivity. Here we demonstrate focusing a hard X-ray beam to an 8 nm focus using a volume zone plate (also referred to as a wedged multilayer Laue lens). This lens was constructed using a new deposition technique that enabled the independent control of the angle and thickness of diffracting layers to microradian and nanometer precision, respectively. This ensured that the Bragg condition is satisfied at each point along the lens, leading to a high numerical aperture that is limited only by its extent. We developed a phase-shifting interferometric method based on ptychography to characterise the lens focus. The precision of the fabrication and characterisation demonstrated here provides the path to efficient X-ray optics for imaging at 1 nm resolution.
New numeric data packages from CDIAC
Hahn, C.J.; Warren, S.G.; London, J.
1995-12-31
This article describes 6 numerical data packages related to climate and greenhouse gas concentrations: Edited synoptic cloud reports from ships and land stations (1982-1991); Carbon dioxide concentrations in surface water and the atmosphere (1986-1989); Carbon-13 isotopic abundance and concentration of atmospheric methane for background air (1978-1989); Six and Three hourly meteorological observations from 223 USSR stations; Global, regional and national annual CO2 emission estimates from fossil-fuel burning, hydraulic-cement production, and gas flaring (1950-1992); continental-scale estimates of biotic carbon flux from land-cover change (1850-1980); Carbon dioxide, hydrographic and chemical data in the south Atlantic Ocean (February-March 1991).
NUMERICAL MODELING OF CATHODE CONTACT MATERIAL DENSIFICATION
Koeppel, Brian J.; Liu, Wenning N.; Stephens, Elizabeth V.; Khaleel, Mohammad A.
2011-11-01
Numerical modeling was used to simulate the constrained sintering process of the cathode contact layer during assembly of solid oxide fuel cells (SOFCs). A finite element model based on the continuum theory for sintering of porous bodies was developed and used to investigate candidate low-temperature cathode contact materials. Constitutive parameters for various contact materials under investigation were estimated from dilatometry screening tests, and the influence of processing time, processing temperature, initial grain size, and applied compressive stress on the free sintering response was predicted for selected candidate materials. The densification behavior and generated stresses within a 5-cell planar SOFC stack during sintering, high temperature operation, and room temperature shutdown were predicted. Insufficient constrained densification was observed in the stack at the proposed heat treatment, but beneficial effects of reduced grain size, compressive stack preload, and reduced thermal expansion coefficient on the contact layer densification and stresses were observed.
Very high numerical aperture light transmitting device
Allison, Stephen W.; Boatner, Lynn A.; Sales, Brian C.
1998-01-01
A new light-transmitting device using a SCIN glass core and a novel calcium sodium cladding has been developed. The very high index of refraction, radiation hardness, similar solubility for rare earths and similar melt and viscosity characteristics of core and cladding materials makes them attractive for several applications such as high-numerical-aperture optical fibers and specialty lenses. Optical fibers up to 60 m in length have been drawn, and several simple lenses have been designed, ground, and polished. Preliminary results on the ability to directly cast optical components of lead-indium phosphate glass are also discussed as well as the suitability of these glasses as a host medium for rare-earth ion lasers and amplifiers.
Direct numerical simulation of turbulent reacting flows
Chen, J.H.
1993-12-01
The development of turbulent combustion models that reflect some of the most important characteristics of turbulent reacting flows requires knowledge about the behavior of key quantities in well defined combustion regimes. In turbulent flames, the coupling between the turbulence and the chemistry is so strong in certain regimes that is is very difficult to isolate the role played by one individual phenomenon. Direct numerical simulation (DNS) is an extremely useful tool to study in detail the turbulence-chemistry interactions in certain well defined regimes. Globally, non-premixed flames are controlled by two limiting cases: the fast chemistry limit, where the turbulent fluctuations. In between these two limits, finite-rate chemical effects are important and the turbulence interacts strongly with the chemical processes. This regime is important because industrial burners operate in regimes in which, locally the flame undergoes extinction, or is at least in some nonequilibrium condition. Furthermore, these nonequilibrium conditions strongly influence the production of pollutants. To quantify the finite-rate chemistry effect, direct numerical simulations are performed to study the interaction between an initially laminar non-premixed flame and a three-dimensional field of homogeneous isotropic decaying turbulence. Emphasis is placed on the dynamics of extinction and on transient effects on the fine scale mixing process. Differential molecular diffusion among species is also examined with this approach, both for nonreacting and reacting situations. To address the problem of large-scale mixing and to examine the effects of mean shear, efforts are underway to perform large eddy simulations of round three-dimensional jets.
1997-05-01
The U.S. Department of Energy has asked Gustavson Associates, Inc. to serve as an Independent Petroleum Consultant under contract DE-AC01-96FE64202. This authorizes a study and recommendations regarding future development of Naval Petroleum Reserve No. 3 (NPR-3) in Natrona County, Wyoming. The report that follows is the Phase I fact-finding and property description for that study. The United States of America owns 100 percent of the mineral rights and surface rights in 9,321-acre NPR-3. This property comprises the Teapot Dome oil field and related production, processing and other facilities. Discovered in 1914, this field has 632 wells producing 1,807 barrels of oil per day. Production revenues are about $9.5 million per year. Remaining recoverable reserves are approximately 1.3 million barrels of oil. Significant plugging and abandonment (P&A) and environmental liabilities are present.
An Updated Numerical Model Of The Larderello-Travale Geothermal...
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Numerical Model Of The Larderello-Travale Geothermal System, Italy Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: An Updated Numerical Model Of...
Numerical simulation of Rayleigh-Taylor instabilities involving solids
Chang, Chong H.
2015-11-20
This report is a description of research performed by LANL regarding numeric simulations of Rayleigh-Taylor instability.
Numerical Modeling Of Basin And Range Geothermal Systems | Open...
Open Energy Information (Open El) [EERE & EIA]
for extensional geothermal systems that include structure, heat input, and permeability distribution have been established using numerical models. Extensional geothermal...
High numerical aperture multilayer Laue lenses
Morgan, Andrew J.; Prasciolu, Mauro; Andrejczuk, Andrzej; Krzywinski, Jacek; Meents, Alke; Pennicard, David; Graafsma, Heinz; Barty, Anton; Bean, Richard J.; Barthelmess, Miriam; et al
2015-06-01
The ever-increasing brightness of synchrotron radiation sources demands improved X-ray optics to utilise their capability for imaging and probing biological cells, nanodevices, and functional matter on the nanometer scale with chemical sensitivity. Here we demonstrate focusing a hard X-ray beam to an 8 nm focus using a volume zone plate (also referred to as a wedged multilayer Laue lens). This lens was constructed using a new deposition technique that enabled the independent control of the angle and thickness of diffracting layers to microradian and nanometer precision, respectively. This ensured that the Bragg condition is satisfied at each point along themore » lens, leading to a high numerical aperture that is limited only by its extent. We developed a phase-shifting interferometric method based on ptychography to characterise the lens focus. The precision of the fabrication and characterisation demonstrated here provides the path to efficient X-ray optics for imaging at 1 nm resolution.« less
Numerical simulations of capillary barrier field tests
Morris, C.E.; Stormont, J.C.
1997-12-31
Numerical simulations of two capillary barrier systems tested in the field were conducted to determine if an unsaturated flow model could accurately represent the observed results. The field data was collected from two 7-m long, 1.2-m thick capillary barriers built on a 10% grade that were being tested to investigate their ability to laterally divert water downslope. One system had a homogeneous fine layer, while the fine soil of the second barrier was layered to increase its ability to laterally divert infiltrating moisture. The barriers were subjected first to constant infiltration while minimizing evaporative losses and then were exposed to ambient conditions. The continuous infiltration period of the field tests for the two barrier systems was modelled to determine the ability of an existing code to accurately represent capillary barrier behavior embodied in these two designs. Differences between the field test and the model data were found, but in general the simulations appeared to adequately reproduce the response of the test systems. Accounting for moisture retention hysteresis in the layered system will potentially lead to more accurate modelling results and is likely to be important when developing reasonable predictions of capillary barrier behavior.
Self-similar radiation from numerical Rosenau-Hyman compactons
Rus, Francisco Villatoro, Francisco R.
2007-11-10
The numerical simulation of compactons, solitary waves with compact support, is characterized by the presence of spurious phenomena, as numerically induced radiation, which is illustrated here using four numerical methods applied to the Rosenau-Hyman K(p, p) equation. Both forward and backward radiations are emitted from the compacton presenting a self-similar shape which has been illustrated graphically by the proper scaling. A grid refinement study shows that the amplitude of the radiations decreases as the grid size does, confirming its numerical origin. The front velocity and the amplitude of both radiations have been studied as a function of both the compacton and the numerical parameters. The amplitude of the radiations decreases exponentially in time, being characterized by a nearly constant scaling exponent. An ansatz for both the backward and forward radiations corresponding to a self-similar function characterized by the scaling exponent is suggested by the present numerical results.
Numerical analysis and measurement in corner-fired furnace
Zhengjun, S.; Rongsheng, G.
1999-07-01
For several years, numerical analysis has been successfully used by Dongfang Boiler (Group) Co., Ltd. at a 200MW boiler, a 300MW boiler and so on, which were designed and made by DBC. The distribution of results is agreement each other between numerical analysis and measurement. In conclusion, it is considered that numerical analysis can be used as an important reference method in pulverized coal boiler design and test.
Numerical Verification of Bounce Harmonic Resonances in Neoclassical
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Toroidal Viscosity for Tokamaks (Technical Report) | SciTech Connect Numerical Verification of Bounce Harmonic Resonances in Neoclassical Toroidal Viscosity for Tokamaks Citation Details In-Document Search Title: Numerical Verification of Bounce Harmonic Resonances in Neoclassical Toroidal Viscosity for Tokamaks This Letter presents the rst numerical veri cation for the bounce-harmonic (BH) resonance phenomena of the neoclassical transport in a tokamak perturbed by non-axisymmetric magnetic
Development of Numerical Simulation Capabilities for In Situ...
Office of Scientific and Technical Information (OSTI)
for In Situ Heating of Oil Shale Citation Details In-Document Search Title: Development of Numerical Simulation Capabilities for In Situ Heating of Oil Shale Authors: Hoda, ...
Numerical Modelling of Geothermal Systems a Short Introduction...
Open Energy Information (Open El) [EERE & EIA]
Modelling of Geothermal Systems a Short Introduction Jump to: navigation, search OpenEI Reference LibraryAdd to library General: Numerical Modelling of Geothermal Systems a Short...
Accurate and fast numerical solution of Poisson s equation for...
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Citation Details In-Document Search Title: Accurate and fast numerical solution of Poisson ... Our method avoids all ill-convergent sums, is simple, accurate, efficient, and works ...
Info-Gap Analysis of Truncation Errors in Numerical Simulations...
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Title: Info-Gap Analysis of Truncation Errors in Numerical Simulations. Authors: Kamm, James R. ; Witkowski, Walter R. ; Rider, William J. ; Trucano, Timothy Guy ; Ben-Haim, Yakov. ...
Info-Gap Analysis of Numerical Truncation Errors. (Conference...
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Title: Info-Gap Analysis of Numerical Truncation Errors. Authors: Kamm, James R. ; Witkowski, Walter R. ; Rider, William J. ; Trucano, Timothy Guy ; Ben-Haim, Yakov. Publication ...
A Numerical Evaluation Of Electromagnetic Methods In Geothermal...
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Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: A Numerical Evaluation Of Electromagnetic Methods In Geothermal Exploration - Discussion...
Numerical Modeling At Coso Geothermal Area (1995) | Open Energy...
Open Energy Information (Open El) [EERE & EIA]
transform is employed to characterize guided-wave's velocity-frequency dispersion, and numerical methods are used to simulate the guided-wave propagation. The modeling...
Numerical Simulation of Ni Grain Growth in a Thermal Gradient
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665C Numerical Simulation of Ni Grain Growth in a Thermal Gradient Sandia National Laboratories John A. Mitchell and Veena Tikare Sandia National Laboratories, Albuquerque New ...
Direct Numerical Simulations and Robust Predictions of Cloud...
U.S. Department of Energy (DOE) all webpages (Extended Search)
cloud. Credit: Computational Science and Engineering Laboratory, ETH Zurich, Switzerland Direct Numerical Simulations and Robust Predictions of Cloud Cavitation Collapse PI Name:...
Numerical simulations for low energy nuclear reactions including...
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Numerical simulations for low energy nuclear reactions including direct channels to ... Visit OSTI to utilize additional information resources in energy science and technology. A ...
Development of Numerical Simulation Capabilities for In Situ...
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Numerical Simulation Capabilities for In Situ Heating of Oil Shale Hoda, Nazish ExxonMobil Upstream Research Company, Houston, TX, USA; Fang, Chen ExxonMobil Upstream Research...
Using fully coupled hydro-geomechanical numerical test bed to...
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test bed to study reservoir stimulation with low hydraulic pressure Citation Details In-Document Search Title: Using fully coupled hydro-geomechanical numerical test bed to ...
Final Report on Experimental and Numerical Modeling Activities...
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Technical Report: Final Report on Experimental and Numerical Modeling Activities for the Newark Basin Citation Details In-Document Search Title: Final Report on Experimental and ...
Numerical Analysis of Fixed Point Algorithms in the Presence...
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in the Presence of Hardware Faults Citation Details In-Document Search Title: Numerical Analysis of Fixed Point Algorithms in the Presence of Hardware Faults You are ...
A review of recent advances of numerical simulations of microscale...
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Due to the reformer's small size, numerical simulations are critical to understand heat and mass transfer phenomena occurring in the systems. This paper reviews the development of ...
History, Applications, Numerical Values and Problems with the...
U.S. Department of Energy (DOE) all webpages (Extended Search)
Numerical Values and Problems with the Calculation of EROI (Energy Return on Energy Investment) Professor Charles Hall State University of NY College of Environmental Science and...
An Integrated Experimental and Numerical Study: Developing a...
Open Energy Information (Open El) [EERE & EIA]
in a numerical simulator (modified version of TOUGH2) that can adjust porosity and permeability fields according to experimentally observed chemical fluid-rock interactions...
Numerical Modeling At Raft River Geothermal Area (1983) | Open...
Open Energy Information (Open El) [EERE & EIA]
Raft River Geothermal Area (1983) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Numerical Modeling At Raft River Geothermal Area (1983)...
Numerical simulation of the environmental impact of hydraulic...
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Numerical simulation of the environmental impact of hydraulic fracturing of tightshale gas reservoirs on near-surface groundwater: Background, base cases, shallow reservoirs,...
Numerical Modeling At Lightning Dock Geothermal Area (O'Brien...
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Basin Additional References Retrieved from "http:en.openei.orgwindex.php?titleNumericalModelingAtLightningDockGeothermalArea(O%27Brien,EtAl.,1984)&oldid762871...
Y-12: Seawolf to National Prototype Center
U.S. Department of Energy (DOE) all webpages (Extended Search)
Propulsor, which ultimately led to Y-12 being designated as the National Prototype Center. ... This "propulsor development center" at Y-12 led to other opportunities for unique designs ...
NONE
1995-12-31
This bill would give the Secretary of Energy authority to lease lands within the Naval oil shale reserves to private entities for the purpose of surveying for and developing oil and gas resources from the land (other than oil shale). It also allows the Bureau of Land Management to be used as a leasing agent, establishes rules on royalties, and the sharing of royalties with the state, and covers the transfer of existing equipment.
Numerical Modeling of PCCI Combustion | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
PCCI Combustion Numerical Modeling of PCCI Combustion 2004 Diesel Engine Emissions Reduction (DEER) Conference Presentation: Lawrence Livermore National Laboratory/University of Michigan 2004_deer_flowers.pdf (252.97 KB) More Documents & Publications Modeling of HCCI and PCCI Combustion Processes Bridging the Gap between Fundamental Physics and Chemistry and Applied Models for HCCI Engines Numerical Modeling of HCCI Combustion
Simple intrinsic defects in GaAs : numerical supplement.
Schultz, Peter Andrew
2012-04-01
This Report presents numerical tables summarizing properties of intrinsic defects in gallium arsenide, GaAs, as computed by density functional theory. This Report serves as a numerical supplement to the results published in: P.A. Schultz and O.A. von Lilienfeld, 'Simple intrinsic defects in GaAs', Modelling Simul. Mater. Sci Eng., Vol. 17, 084007 (2009), and intended for use as reference tables for a defect physics package in device models. The numerical results for density functional theory calculations of properties of simple intrinsic defects in gallium arsenide are presented.
Use of ARM observations and numerical models to determine radiative...
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We investigated whether the West African anvil clouds connected with squall line MCSs passing over the Niamey ARM site could be simulated in a numerical model by comparing the ...
Numerical simulation experiments on the long-term evolution of...
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the long-term evolution of a CO2 plume under a sloping caprock Citation Details In-Document Search Title: Numerical simulation experiments on the long-term evolution of a CO2 plume ...
Numerical study of heterogeneous mean temperature and shock wave...
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We numerically study the gas oscillation with shock wave in a resonator of square cross section by solving the initial and boundary value problem of the system of three-dimensional ...
A Numerical Evaluation Of Electromagnetic Methods In Geothermal...
Open Energy Information (Open El) [EERE & EIA]
L Pellerin, J M Johnston & G W Hohmann, Geophysics, 61(1), 1996, Pp 121-130 Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: A Numerical...
Numerical simulations shed new light on early universe
U.S. Department of Energy (DOE) all webpages (Extended Search)
Numerical simulations shed new light on early universe Numerical simulations shed new light on early universe The code simulates conditions during the first few minutes of cosmological evolution to model the role of neutrinos, nuclei and other particles in shaping the early universe. April 21, 2016 Los Alamos scientists developed the BURST computer code to predict-to unprecedented precision-the amounts of light nuclei synthesized in the Big Bang. Los Alamos scientists developed the BURST
Recent advances in two-phase flow numerics
Mahaffy, J.H.; Macian, R.
1997-07-01
The authors review three topics in the broad field of numerical methods that may be of interest to individuals modeling two-phase flow in nuclear power plants. The first topic is iterative solution of linear equations created during the solution of finite volume equations. The second is numerical tracking of macroscopic liquid interfaces. The final area surveyed is the use of higher spatial difference techniques.
Numerical Investigation of Advanced Compressor Technologies | Department of
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Energy Investigation of Advanced Compressor Technologies Numerical Investigation of Advanced Compressor Technologies The purpose of the work was to explore advanced boost technologies to support clean diesel combustion, such as HCCI/LTC applications. deer08_sun.pdf (189.93 KB) More Documents & Publications Numerical Investigation of Advanced Compressor Technologies Advanced boost system development for diesel HCCI/LTC applications Advanced Boost System Development for Diesel HCCI/LTC
MEMORANDUM OF UNDERSTANDING Between The Numerical Algorithms Group Ltd
U.S. Department of Energy (DOE) all webpages (Extended Search)
Between The Numerical Algorithms Group Ltd and The University of California, as Management and Operating Contractor for Lawrence Berkeley National Laboratory on a Visitor Exchange Program This Memorandum of Understanding (MOU) is by and between the Numerical Algorithms Group Ltd (NAG) with a registered address at: Wilkinson House, Jordan hill Road, Oxford, UK and the University of California, as Management and Operating Contractor for Lawrence Berkeley National Laboratory, including its
An integrated experimental and numerical study: Developing a reaction
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
transport model that couples chemical reactions of mineral dissolution/precipitation with spatial and temporal flow variations in CO2/brine/rock systems | Department of Energy An integrated experimental and numerical study: Developing a reaction transport model that couples chemical reactions of mineral dissolution/precipitation with spatial and temporal flow variations in CO2/brine/rock systems An integrated experimental and numerical study: Developing a reaction transport model that
Mathematical and Numerical Analyses of Peridynamics for Multiscale Materials Modeling
Gunzburger, Max
2015-02-17
We have treated the modeling, analysis, numerical analysis, and algorithmic development for nonlocal models of diffusion and mechanics. Variational formulations were developed and finite element methods were developed based on those formulations for both steady state and time dependent problems. Obstacle problems and optimization problems for the nonlocal models were also treated and connections made with fractional derivative models.
Simple intrinsic defects in InAs : numerical predictions.
Schultz, Peter Andrew
2013-03-01
This Report presents numerical tables summarizing properties of intrinsic defects in indium arsenide, InAs, as computed by density functional theory using semi-local density functionals, intended for use as reference tables for a defect physics package in device models.
Translation and integration of numerical atomic orbitals in linear molecules
Heinäsmäki, Sami
2014-02-14
We present algorithms for translation and integration of atomic orbitals for LCAO calculations in linear molecules. The method applies to arbitrary radial functions given on a numerical mesh. The algorithms are based on pseudospectral differentiation matrices in two dimensions and the corresponding two-dimensional Gaussian quadratures. As a result, multicenter overlap and Coulomb integrals can be evaluated effectively.
Numerical Modeling At Neal Hot Springs Geothermal Area (U.S....
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Area Exploration Technique Numerical Modeling Activity Date 2011 - 2011 Usefulness useful DOE-funding Unknown Exploration Basis A numerical reservoir model was created to...
Naval Reactors | Y-12 National Security Complex
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Current Issues & Trends See more › Hurricane activity drives declines in Gulf of Mexico natural gas production productionweatherGulf of Mexico Gulf Coast's first ethane shipment soon to leave for Europe exportsEuropeethane As Japan and South Korea import less LNG, other Asian countries begin to import more LNGChinaIndiaJapanSouth Korea Future U.S. tight oil and shale gas production depends on resources, technology, markets productionshaledrillingtight oilAEO2016 Asian LNG imports increase
Naval reactors in need of redesign
Kramer, David
2015-05-15
Nonproliferation concerns should propel US Navy to switch to safer nuclear fuel, says FAS task force.
Naval Petroleum Reserves | Department of Energy
Office of Environmental Management (EM)
federal property to Native Americans in the last century. NPR-2 - Enactment of the Energy Policy Act 2005 effected the transfer of administrative jurisdiction and land management...
Numerical method for shear bands in ductile metal with inclusions
Plohr, Jee Yeon N [Los Alamos National Laboratory; Plohr, Bradley J [Los Alamos National Laboratory
2010-01-01
A numerical method for mesoscale simulation of high strain-rate loading of ductile metal containing inclusions is described. Because of small-scale inhomogeneities, such a composite material is prone to localized shear deformation (adiabatic shear bands). The modeling framework is the Generalized Method of Cells of Paley and Aboudi [Mech. Materials, vol. 14, pp. /27-139, 1992], which ensures that the micromechanical response of the material is reflected in the behavior of the composite at the mesoscale. To calculate the effective plastic strain rate when shear bands are present, the analytic and numerical analysis of shear bands by Glimm, Plohr, and Sharp [Mech. Materials, vol. 24, pp. 31-41, 1996] is adapted and extended.
On Numerical Considerations for Modeling Reactive Astrophysical Shocks
Papatheodore, Thomas L; Messer, Bronson
2014-01-01
Simulating detonations in astrophysical environments is often complicated by numerical approximations to shock structure. A common prescription to ensure correct detonation speeds (and associated quantities) is to prohibit burning inside the numerically broadened shock (Fryxell et al. 1989). We have performed a series of simulations to verify the efficacy of this approximation and to understand how resolution and dimensionality might affect its use. Our results show that, in one dimension, prohibiting burning in the shock is important wherever the carbon burning length is not resolved, in keeping with the results of Fryxell et al. (1989). In two dimensions, we find that the prohibition of shock burning effectively inhibits the development of cellular structure for all but the most highly-resolved cases. We discuss the possible impacts this outcome may have on sub-grid models and detonation propagation in Type Ia supernovae.
AEETES---A solar reflux receiver thermal performance numerical model
Hogan, R.E. Jr.
1991-01-01
Reflux solar receivers for dish-Stirling electric power generation systems are currently being investigated by several companies and laboratories. In support of these efforts, the AEETES thermal performance numerical model has been developed to predict thermal performance of pool-boiler and heat-pipe reflux receivers. The formulation of the AEETES numerical model, which is applicable to axisymmetric geometries with asymmetric incident fluxes, is presented in detail. Thermal efficiency predictions agree to within 4.1% with test data from on-sun tests of a pool-boiler reflux receiver. Predicted absorber and sidewall temperatures agree with thermocouple data to within 3.3.% and 7.3%, respectively. The importance of accounting for the asymmetric incident fluxes is demonstrated in comparisons with predictions using azimuthally averaged variables. The predicted receiver heat losses are characterized in terms of convective, solar and infrared radiative, and conductive heat transfer mechanisms. 27 refs., 9 figs., 4 tabs.
Numerical modeling of solar magnetostatic structures bounded by current sheets
Pizzo, V.J. )
1990-12-01
A numerical method for efficiently determining the magnetostatic equilibrium configuration of erupted solar flux concentrations, such as sunspots and flux tubes, is presented. The magnetic structures are taken to be approximately vertically oriented and axisymmetric in the surface layers and are assumed to be isolated from the surrounding photosphere by a vanishingly thin current sheet. Since the location of the current sheet is initially unknown, the final structure is generated iteratively as a free-surface problem, with the magnetic configuration for each iterate being obtained from the horizontal force balance equation, subject to the appropriate boundary conditions. Multigrid methods are used at each stage to solve the equilibrium equation, which is mapped algebraically into a body-fitted coordinate system via transfinite interpolation techniques. Several model flux tubes and sunspots are computed to illustrate the procedure, and the accuracy of the numerical method is assessed against exact analytic solutions. 32 refs.
Numerical study of thermoacoustic convection in a cavity
Fusegi, Toru; Farouk, B.; Oran, E.S.
1995-12-31
Thermoacoustic convection in a two-dimensional cavity is numerically studied. Part of a compressible fluid (Helium) near the center line of the cavity is suddenly energized to generate pressure waves. Numerical solutions are secured by employing a highly accurate explicit method termed LCPFCT algorithm for the convection terms of the full Navier-Stokes equations. Thermoacoustic waves, which decay in large time due to the viscosity of fluid, are of the oscillatory nature. Much higher heat transfer rate can be achieved in an initial stage of transient processes, compared to that due to conduction. When a partial length of the cavity center line is heated, resulting thermoacoustic waves exhibit remarkable two-dimensional patterns.
NREL Receives Numerous Accolades from Industry and DOE - News Releases |
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NREL Receives Numerous Accolades from Industry and DOE Lab honored with awards for sustainability; employees recognized for hydrogen, battery R&D November 8, 2012 The U.S. Department of Energy's (DOE)'s National Renewable Energy Laboratory (NREL) and its employees have garnered awards and recognition from industry groups for advancing energy research as well as furthering the lab's sustainable operating practices. Bryan Pivovar Named Charles W. Tobias Young Investigator by the
Numerical Simulations of Small Non-spherical Particles in Turbulence |
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Argonne Leadership Computing Facility Numerical Simulations of Small Non-spherical Particles in Turbulence Event Sponsor: Mathematics and Computer Science Division LANS Seminar Start Date: Aug 31 2016 - 3:00pm Building/Room: Building 240/Room 1404-1405 Location: Argonne National Laboratory Speaker(s): Nimish Pujara Speaker(s) Title: UC Berkeley Motivated by the ubiquity of natural particles in turbulent flows in the natural environment as well as in many industrial processes, we investigate
Direct Numerical Simulations and Robust Predictions of Cloud Cavitation
U.S. Department of Energy (DOE) all webpages (Extended Search)
Collapse | Argonne Leadership Computing Facility cavitating vapor bubbles above a solid wall This image shows cavitating vapor bubbles above a solid wall. The yellow is a visualization of the pressure peak in the center of the bubble cloud. Credit: Computational Science and Engineering Laboratory, ETH Zurich, Switzerland Direct Numerical Simulations and Robust Predictions of Cloud Cavitation Collapse PI Name: Petros Koumoutsakos PI Email: petros@ethz.ch Institution: ETH Zürich Allocation
Direct Numerical Simulations and Robust Predictions of Cloud Cavitation
U.S. Department of Energy (DOE) all webpages (Extended Search)
Collapse | Argonne Leadership Computing Facility Initiation of cloud cavitation collapse for 50,000 bubbles Initiation of cloud cavitation collapse for 50,000 bubbles. Jonas Sukys, ETH Zurich Direct Numerical Simulations and Robust Predictions of Cloud Cavitation Collapse PI Name: Petros Koumoutsakos PI Email: petros@ethz.ch Institution: ETH Zurich Allocation Program: INCITE Allocation Hours at ALCF: 72 Million Year: 2016 Research Domain: Engineering Cloud cavitation collapse-the evolution
Direct Numerical Simulations of High Reynolds Number Turbulent Channel Flow
U.S. Department of Energy (DOE) all webpages (Extended Search)
| Argonne Leadership Computing Facility Visualization of the spanwise vorticity in a turbulent channel. S. Hoyas and O. Flores while they were at Universidad Politecnica de Madrid Direct Numerical Simulations of High Reynolds Number Turbulent Channel Flow PI Name: Robert Moser PI Email: rmoser@ices.utexas.edu Institution: University of Texas Allocation Program: INCITE Allocation Hours at ALCF: 175 Million Year: 2013 Research Domain: Engineering Approximately 28% of U.S. energy resources are
Numerical simulations of the decay of primordial magnetic turbulence
Kahniashvili, Tina [McWilliams Center for Cosmology and Department of Physics, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, Pennsylvania 15213 (United States); Department of Physics, Laurentian University, Ramsey Lake Road, Sudbury, ON P3E 2C (Canada); Abastumani Astrophysical Observatory, Ilia State University, 2A Kazbegi Ave, Tbilisi, GE-0160 (Georgia); Brandenburg, Axel [Nordita, AlbaNova University Center, Roslagstullsbacken 23, 10691 Stockholm (Sweden); Department of Astronomy, Stockholm University, SE 10691 Stockholm (Sweden); Tevzadze, Alexander G. [Abastumani Astrophysical Observatory, Ilia State University, 2A Kazbegi Ave, Tbilisi, GE-0160 (Georgia); Faculty of Exact and Natural Sciences, Tbilisi State University, 1 Chavchavadze Avenue Tbilisi, GE-0128 (Georgia); Ratra, Bharat [Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, Kansas 66506 (United States)
2010-06-15
We perform direct numerical simulations of forced and freely decaying 3D magnetohydrodynamic turbulence in order to model magnetic field evolution during cosmological phase transitions in the early Universe. Our approach assumes the existence of a magnetic field generated either by a process during inflation or shortly thereafter, or by bubble collisions during a phase transition. We show that the final configuration of the magnetic field depends on the initial conditions, while the velocity field is nearly independent of initial conditions.
Numerical Simulation of Groundwater Withdrawal at the Nevada Test Site
Carroll, Rosemary; Giroux, Brian; Pohll, Greg; Hershey, Ronald; Russell, Charles; Howcroft, William
2004-01-28
Alternative uses of the Nevada Test Site (NTS) may require large amounts of water to construct and/or operate. The only abundant source of water at the NTS is groundwater. This report describes preliminary modeling to quantify the amount of groundwater available for development from three hydrographic areas at the NTS. Modeling was conducted with a three-dimensional transient numerical groundwater flow model.
Numerical Modeling of HCCI Combustion | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
HCCI Combustion Numerical Modeling of HCCI Combustion Presentation given at DEER 2006, August 20-24, 2006, Detroit, Michigan. Sponsored by the U.S. DOE's EERE FreedomCar and Fuel Partnership and 21st Century Truck Programs. 2006_deer_aceves.pdf (840 KB) More Documents & Publications High Fidelity Modeling of Premixed Charge Compression Ignition Engines New Methodologies for Analysis of Premixed Charge Compression Ignition Engines Modeling of HCCI and PCCI Combustion Processes
Dispersion of helically corrugated waveguides: Analytical, numerical, and experimental study
Burt, G.; Ronald, K.; Young, A.R.; Phelps, A.D.R.; Cross, A.W.; Konoplev, I.V.; He, W.; Thomson, J.; Whyte, C.G.; Samsonov, S.V.; Denisov, G.G.; Bratman, V.L.
2004-10-01
Helically corrugated waveguides have recently been studied for use in various applications such as interaction regions in gyrotron traveling-wave tubes and gyrotron backward-wave oscillators and as a dispersive medium for passive microwave pulse compression. The paper presents a summary of various methods that can be used for analysis of the wave dispersion of such waveguides. The results obtained from an analytical approach, simulations with the three-dimensional numerical code MAGIC, and cold microwave measurements are analyzed and compared.
Los Alamos National Laboratory communicators capture numerous awards from
U.S. Department of Energy (DOE) all webpages (Extended Search)
Society for Technical Communication Society for Technical Communication Awards Los Alamos National Laboratory communicators capture numerous awards from Society for Technical Communication Three Los Alamos entries garnered Distinguished Technical Communication awards, the competition's highest award category. April 15, 2010 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering
Numerical solution of sand transport in hydraulic fracturing
Daneshy, A.A.; Crichlow, H.B.
1980-02-07
A numerical solution is developed for the deposition of a propping agent inside a hydraulic fracture. Such parameters as fluid leak-off into the formation, increase in sand concentration caused by leak-off, non-Newtonian fracturing fluids, hindered settling velocity, and an up-to-date geometry are taken into consideration. Three examples investigate the proppant deposition for low-, medium-, and high-viscosity fracturing fluids.
COLLOQUIUM: History, Applications, Numerical Values and Problems with the
U.S. Department of Energy (DOE) all webpages (Extended Search)
Calculation of EROI - Energy Return on (Energy) Investment | Princeton Plasma Physics Lab March 2, 2016, 4:15pm to 5:30pm Colloquia MBG Auditorium COLLOQUIUM: History, Applications, Numerical Values and Problems with the Calculation of EROI - Energy Return on (Energy) Investment Professor Charles Hall State University of NY College of Environmental Science and Forestry Plants and animals are subjected to fierce selective pressure to do the "right thing" energetically, that is to
Numerical simulation of the hydrodynamical combustion to strange quark matter
Niebergal, Brian; Ouyed, Rachid; Jaikumar, Prashanth
2010-12-15
We present results from a numerical solution to the burning of neutron matter inside a cold neutron star into stable u,d,s quark matter. Our method solves hydrodynamical flow equations in one dimension with neutrino emission from weak equilibrating reactions, and strange quark diffusion across the burning front. We also include entropy change from heat released in forming the stable quark phase. Our numerical results suggest burning front laminar speeds of 0.002-0.04 times the speed of light, much faster than previous estimates derived using only a reactive-diffusive description. Analytic solutions to hydrodynamical jump conditions with a temperature-dependent equation of state agree very well with our numerical findings for fluid velocities. The most important effect of neutrino cooling is that the conversion front stalls at lower density (below {approx_equal}2 times saturation density). In a two-dimensional setting, such rapid speeds and neutrino cooling may allow for a flame wrinkle instability to develop, possibly leading to detonation.
Numerical Investigation of Laser Propulsion for Transport in Water Environment
Han Bing; Li Beibei; Zhang Hongchao; Chen Jun; Shen Zhonghua; Lu Jian; Ni Xiaowu
2010-10-08
Problems that cumber the development of the laser propulsion in atmosphere and vacuum are discussed. Based on the theory of interaction between high-intensity laser and materials, as air and water, it is proved that transport in water environment can be impulsed by laser. The process of laser propulsion in water is investigated theoretically and numerically. It shows that not only the laser induced plasma shock wave, but also the laser induced bubble oscillation shock waves and the pressure induced by the collapsing bubble can be used. Many experimental results show that the theory and the numerical results are valid. The numerical result of the contribution of every propulsion source is given in percentage. And the maximum momentum coupling coefficient Cm is given. Laser propulsion in water environment can be applied in many fields. For example, it can provide highly controllable forces of the order of micro-Newton ({mu}N) in microsystems, such as the MEMS (Micro-electromechanical Systems). It can be used as minimally invasive surgery tools of high temporal and spatial resolution. It can be used as the propulsion source in marine survey and exploitation.
Transient productivity index for numerical well test simulations
Blanc, G.; Ding, D.Y.; Ene, A.
1997-08-01
The most difficult aspect of numerical simulation of well tests is the treatment of the Bottom Hole Flowing (BHF) Pressure. In full field simulations, this pressure is derived from the Well-block Pressure (WBP) using a numerical productivity index which accounts for the grid size and permeability, and for the well completion. This productivity index is calculated assuming a pseudo-steady state flow regime in the vicinity of the well and is therefore constant during the well production period. Such a pseudo-steady state assumption is no longer valid for the early time of a well test simulation as long as the pressure perturbation has not reached several grid-blocks around the well. This paper offers two different solutions to this problem: (1) The first one is based on the derivation of a Numerical Transient Productivity Index (NTPI) to be applied to Cartesian grids; (2) The second one is based on the use of a Corrected Transmissibility and Accumulation Term (CTAT) in the flow equation. The representation of the pressure behavior given by both solutions is far more accurate than the conventional one as shown by several validation examples which are presented in the following pages.
Numerical simulation of steam injection processes with solvent
Zerpa, L.; Mendez, Z.
1995-12-31
In Venezuela during recent years, gas oil has been evaluated as an additive to increase steam injection process efficiency. The results of laboratory and field tests have shown a significant improvement in the production behavior. Despite these experiences, it is necessary to complement the information with results obtained from numerical simulation studies in order to know injection parameter effects, such as gas oil concentration, schemes and rates of injection, temperatures, etc., and also some mechanisms involved in the process. In this work, the results achieved in the numerical simulation of displacement tests with steam and gas oil are presented. A fully implicit 2-D thermal, three-phase compositional simulator was used to obtain all the data presented in this paper The numerical simulation results show a similar oil production performance to those obtained in the displacement tests with injection of gas oil and steam simultaneously. These results indicate rising of the production rate when the solvent concentration increases. They also reveal that the solvent co-injection scheme improves the productivity in relation to the gas oil pre-injection at low temperature. However, when gas oil is pre-injected at higher temperature, the oil production performance is similar to the co-injection scheme performance. This can attribute to the favorable temperature effect on the diffusion mechanisms. On the other hand, an increase of the gas oil injection rate causes a productivity reduction. In addition, the gas oil capacity to remove more viscous fractions than the original crude was verified. It was determined that the gas oil light fraction volatilization contributes to the process improvement. In general, these results confirm the benefit of using solvent and contribute to the understanding of process mechanisms.
ASSIMILATION OF DOPPLER RADAR DATA INTO NUMERICAL WEATHER MODELS
Chiswell, S.; Buckley, R.
2009-01-15
During the year 2008, the United States National Weather Service (NWS) completed an eight fold increase in sampling capability for weather radars to 250 m resolution. This increase is expected to improve warning lead times by detecting small scale features sooner with increased reliability; however, current NWS operational model domains utilize grid spacing an order of magnitude larger than the radar data resolution, and therefore the added resolution of radar data is not fully exploited. The assimilation of radar reflectivity and velocity data into high resolution numerical weather model forecasts where grid spacing is comparable to the radar data resolution was investigated under a Laboratory Directed Research and Development (LDRD) 'quick hit' grant to determine the impact of improved data resolution on model predictions with specific initial proof of concept application to daily Savannah River Site operations and emergency response. Development of software to process NWS radar reflectivity and radial velocity data was undertaken for assimilation of observations into numerical models. Data values within the radar data volume undergo automated quality control (QC) analysis routines developed in support of this project to eliminate empty/missing data points, decrease anomalous propagation values, and determine error thresholds by utilizing the calculated variances among data values. The Weather Research and Forecasting model (WRF) three dimensional variational data assimilation package (WRF-3DVAR) was used to incorporate the QC'ed radar data into input and boundary conditions. The lack of observational data in the vicinity of SRS available to NWS operational models signifies an important data void where radar observations can provide significant input. These observations greatly enhance the knowledge of storm structures and the environmental conditions which influence their development. As the increase in computational power and availability has made higher
Numerical simulation of carbon arc discharge for nanoparticle synthesis
Kundrapu, M.; Keidar, M.
2012-07-15
Arc discharge with catalyst-filled carbon anode in helium background was used for the synthesis of carbon nanoparticles. In this paper, we present the results of numerical simulation of carbon arc discharges with arc current varying from 10 A to 100 A in a background gas pressure of 68 kPa. Anode sublimation rate and current voltage characteristics are compared with experiments. Distribution of temperature and species density, which is important for the estimation of the growth of nanoparticles, is obtained. The probable location of nanoparticle growth region is identified based on the temperature range for the formation of catalyst clusters.
Numerical studies of the radiant flash pyrolysis of cellulose
Kothari, V.; Antal, M.J. Jr.
1983-01-01
When biomass particles are heated very rapidly (temperatures greater than 1000 degrees/s) in an oxygen free environment, they undergo pyrolysis with the formation of little or no char. If concentrated solar energy is used to rapidly heat the particles their temperature may exceed that of the surrounding gaseous environment by several hundred degrees Celsius when pyrolysis occurs. This two temperature effect gives rise to the formation of high yields of syrups from the pyrolyzing biomass. Numerical exploration of the combined effects of heat and mass transfer on the radiative flash pyrolysis phenonmena are described in this paper. 12 references.
Numerical calculation of the ion polarization in MEIC
Derbenev, Yaroslav; Lin, Fanglei; Morozov, Vasiliy; Zhang, Yuhong; Kondratenko, Anatoliy; Kondratenko, M A; Filatov, Yury
2015-09-01
Ion polarization in the Medium-energy Electron-Ion Collider (MEIC) is controlled by means of universal 3D spin rotators designed on the basis of "weak" solenoids. We use numerical calculations to demonstrate that the 3D rotators have negligible effect on the orbital properties of the ring. We present calculations of the polarization dynamics along the collider's orbit for both longitudinal and transverse polarization directions at a beam interaction point. We calculate the degree of depolarization due to the longitudinal and transverse beam emittances in case when the zero-integer spin resonance is compensated.
Advanced numerical methods in mesh generation and mesh adaptation
Lipnikov, Konstantine; Danilov, A; Vassilevski, Y; Agonzal, A
2010-01-01
Numerical solution of partial differential equations requires appropriate meshes, efficient solvers and robust and reliable error estimates. Generation of high-quality meshes for complex engineering models is a non-trivial task. This task is made more difficult when the mesh has to be adapted to a problem solution. This article is focused on a synergistic approach to the mesh generation and mesh adaptation, where best properties of various mesh generation methods are combined to build efficiently simplicial meshes. First, the advancing front technique (AFT) is combined with the incremental Delaunay triangulation (DT) to build an initial mesh. Second, the metric-based mesh adaptation (MBA) method is employed to improve quality of the generated mesh and/or to adapt it to a problem solution. We demonstrate with numerical experiments that combination of all three methods is required for robust meshing of complex engineering models. The key to successful mesh generation is the high-quality of the triangles in the initial front. We use a black-box technique to improve surface meshes exported from an unattainable CAD system. The initial surface mesh is refined into a shape-regular triangulation which approximates the boundary with the same accuracy as the CAD mesh. The DT method adds robustness to the AFT. The resulting mesh is topologically correct but may contain a few slivers. The MBA uses seven local operations to modify the mesh topology. It improves significantly the mesh quality. The MBA method is also used to adapt the mesh to a problem solution to minimize computational resources required for solving the problem. The MBA has a solid theoretical background. In the first two experiments, we consider the convection-diffusion and elasticity problems. We demonstrate the optimal reduction rate of the discretization error on a sequence of adaptive strongly anisotropic meshes. The key element of the MBA method is construction of a tensor metric from hierarchical edge
Numerical routines for predicting ignition in pyrotechnic devices
Pierce, K.G.
1986-06-01
Two numerical models of the thermal processes leading to ignition in a pyrotechnic device have been developed. These models are based on finite difference approximations to the heat diffusion equation, with temperature-dependent thermal properties, in a single spatial coordinate. The derivation of the finite difference equations is discussed and the methods employed at boundaries and interfaces are given. The sources of the thermal-properties data are identified and how these data are used is explained. The program structure is explained and example runs of the programs are given.
High numerical aperture projection system for extreme ultraviolet projection lithography
Hudyma, Russell M.
2000-01-01
An optical system is described that is compatible with extreme ultraviolet radiation and comprises five reflective elements for projecting a mask image onto a substrate. The five optical elements are characterized in order from object to image as concave, convex, concave, convex, and concave mirrors. The optical system is particularly suited for ring field, step and scan lithography methods. The invention uses aspheric mirrors to minimize static distortion and balance the static distortion across the ring field width which effectively minimizes dynamic distortion. The present invention allows for higher device density because the optical system has improved resolution that results from the high numerical aperture, which is at least 0.14.
Diffusive mesh relaxation in ALE finite element numerical simulations
Dube, E.I.
1996-06-01
The theory for a diffusive mesh relaxation algorithm is developed for use in three-dimensional Arbitary Lagrange/Eulerian (ALE) finite element simulation techniques. This mesh relaxer is derived by a variational principle for an unstructured 3D grid using finite elements, and incorporates hourglass controls in the numerical implementation. The diffusive coefficients are based on the geometric properties of the existing mesh, and are chosen so as to allow for a smooth grid that retains the general shape of the original mesh. The diffusive mesh relaxation algorithm is then applied to an ALE code system, and results from several test cases are discussed.
Numerical analysis of decoy state quantum key distribution protocols
Harrington, Jim W; Rice, Patrick R
2008-01-01
Decoy state protocols are a useful tool for many quantum key distribution systems implemented with weak coherent pulses, allowing significantly better secret bit rates and longer maximum distances. In this paper we present a method to numerically find optimal three-level protocols, and we examine how the secret bit rate and the optimized parameters are dependent on various system properties, such as session length, transmission loss, and visibility. Additionally, we show how to modify the decoy state analysis to handle partially distinguishable decoy states as well as uncertainty in the prepared intensities.
Numerical simulation model for vertical flow in geothermal wells
Tachimori, M.
1982-01-01
A numerical simulation model for vertical flow in geothermal wells is presented. The model consists of equations for the conservation of mass, momentum, and energy, for thermodynamic state of water, for friction losses, for slip velocity relations, and of the criteria for various flow regimes. A new set of correlations and criteria is presented for two-phase flow to improve the accuracy of predictions; bubbly flow - Griffith and Wallis correlation, slug flow - Nicklin et al. one, annular-mist flow - Inoue and Aoki and modified by the author. The simulation method was verified by data from actual wells.
Numerical simulation of multi-layered textile composite reinforcement forming
Wang, P.; Hamila, N.; Boisse, P.
2011-05-04
One important perspective in aeronautics is to produce large, thick or/and complex structural composite parts. The forming stage presents an important role during the whole manufacturing process, especially for LCM processes (Liquid Composites Moulding) or CFRTP (Continuous Fibre Reinforcements and Thermoplastic resin). Numerical simulations corresponding to multi-layered composite forming allow the prediction for a successful process to produce the thick parts, and importantly, the positions of the fibres after forming to be known. This paper details a set of simulation examples carried out by using a semi-discrete shell finite element made up of unit woven cells. The internal virtual work is applied on all woven cells of the element taking into account tensions, in-plane shear and bending effects. As one key problem, the contact behaviours of tool/ply and ply/ply are described in the numerical model. The simulation results not only improve our understanding of the multi-layered composite forming process but also point out the importance of the fibre orientation and inter-ply friction during formability.
A hybrid numerical fluid dynamics code for resistive magnetohydrodynamics
Energy Science and Technology Software Center (OSTI)
2006-04-01
Spasmos is a computational fluid dynamics code that uses two numerical methods to solve the equations of resistive magnetohydrodynamic (MHD) flows in compressible, inviscid, conducting media[1]. The code is implemented as a set of libraries for the Python programming language[2]. It represents conducting and non-conducting gases and materials with uncomplicated (analytic) equations of state. It supports calculations in 1D, 2D, and 3D geometry, though only the 1D configuation has received significant testing to date. Becausemore » it uses the Python interpreter as a front end, users can easily write test programs to model systems with a variety of different numerical and physical parameters. Currently, the code includes 1D test programs for hydrodynamics (linear acoustic waves, the Sod weak shock[3], the Noh strong shock[4], the Sedov explosion[5], magnetic diffusion (decay of a magnetic pulse[6], a driven oscillatory "wine-cellar" problem[7], magnetic equilibrium), and magnetohydrodynamics (an advected magnetic pulse[8], linear MHD waves, a magnetized shock tube[9]). Spasmos current runs only in a serial configuration. In the future, it will use MPI for parallel computation.« less
Numerical and experimental analysis of a retrievable offshore loading facility
Sterndorff, M.J.; O`Brien, P.
1995-12-31
ROLF (Retrievable Offshore Loading Facility) has been proposed as an alternative offshore oil export tanker loading system for the North Sea. The system consists of a flexible riser ascending from the seabed in a lazy wave configuration to the bow of a dynamically positioned tanker. In order to supplant and support the numerical analyses performed to design the system, an extensive model test program was carried out in a 3D offshore basin at scale 1:50. A model riser with properties equivalent to the properties of the oil filled prototype riser installed in seawater was tested in several combinations of waves and current. During the tests the forces at the bow of the tanker and at the pipeline end manifold were measured together with the motions of the tanker and the riser. The riser motions were measured by means of a video based 3D motion monitoring system. Of special importance was accurate determination of the minimum bending radius for the riser. This was derived based on the measured riser motions. The results of the model tests were compared to numerical analyses by an MCS proprietary riser analysis program.
Numerical analysis of the spatial range of the Kondo effect
Busser, C. A.; Martins, G. B.; Ribeiro, L. Costa; Vernek, E.; Anda, E. V.; Dagotto, Elbio R
2010-01-01
The spatial length of the Kondo screening is still a controversial issue related to Kondo physics. While renormalization-group and Bethe-Ansatz solutions have provided detailed information about the thermodynamics of magnetic impurities, they are insufficient to study the effect on the surrounding electrons, i.e., the spatial range of the correlations created by the Kondo effect between the localized magnetic moment and the conduction electrons. The objective of this work is to present a quantitative way of measuring the extension of these correlations by studying their effect directly on the local density of states (LDOS) at arbitrary distances from the impurity. The numerical techniques used, the embedded cluster approximation, the finite-U slave bosons, and numerical renormalization group, calculate the Green s functions in real space. With this information, one can calculate how the local density of states away from the impurity is modified by its presence, below and above the Kondo temperature, and then estimate the range of the disturbances in the noninteracting Fermi sea due to the Kondo effect, and how it changes with the Kondo temperature TK. The results obtained agree with results obtained through spin-spin correlations, showing that the LDOS captures the phenomenology of the Kondo cloud as well.
Numerical Model for Conduction-Cooled Current Lead Heat Loads
White, M.J.; Wang, X.L.; Brueck, H.D.; /DESY
2011-06-10
Current leads are utilized to deliver electrical power from a room temperature junction mounted on the vacuum vessel to a superconducting magnet located within the vacuum space of a cryostat. There are many types of current leads used at laboratories throughout the world; however, conduction-cooled current leads are often chosen for their simplicity and reliability. Conduction-cooled leads have the advantage of using common materials, have no superconducting/normal state transition, and have no boil-off vapor to collect. This paper presents a numerical model for conduction-cooled current lead heat loads. This model takes into account varying material and fluid thermal properties, varying thicknesses along the length of the lead, heat transfer in the circumferential and longitudinal directions, electrical power dissipation, and the effect of thermal intercepts. The model is validated by comparing the numerical model results to ideal cases where analytical equations are valid. In addition, the XFEL (X-Ray Free Electron Laser) prototype current leads are modeled and compared to the experimental results from testing at DESY's XFEL Magnet Test Stand (XMTS) and Cryomodule Test Bench (CMTB).
A hybrid numerical fluid dynamics code for resistive magnetohydrodynamics
2006-04-01
Spasmos is a computational fluid dynamics code that uses two numerical methods to solve the equations of resistive magnetohydrodynamic (MHD) flows in compressible, inviscid, conducting media[1]. The code is implemented as a set of libraries for the Python programming language[2]. It represents conducting and non-conducting gases and materials with uncomplicated (analytic) equations of state. It supports calculations in 1D, 2D, and 3D geometry, though only the 1D configuation has received significant testing to date. Because it uses the Python interpreter as a front end, users can easily write test programs to model systems with a variety of different numerical and physical parameters. Currently, the code includes 1D test programs for hydrodynamics (linear acoustic waves, the Sod weak shock[3], the Noh strong shock[4], the Sedov explosion[5], magnetic diffusion (decay of a magnetic pulse[6], a driven oscillatory "wine-cellar" problem[7], magnetic equilibrium), and magnetohydrodynamics (an advected magnetic pulse[8], linear MHD waves, a magnetized shock tube[9]). Spasmos current runs only in a serial configuration. In the future, it will use MPI for parallel computation.
Not Available
1994-10-01
The purpose and need of the proposed action, which is the installation of an overhead powerline extension from an Naval Petroleum Reserve No. 1 (NPR-1) power source to the WKWD Station A, is to significantly reduce NPR-1`s overall utility costs. While the proposed action is independently justified on its own merits and is not tied to the proposed NPR-1 Cogeneration Facility, the proposed action would enable DOE to tie the NPR-1 fresh water pumps at Station A into the existing NPR-1 electrical distribution system. With the completion of the cogeneration facility in late 1994 or early 1995, the proposed action would save additional utility costs. This report deals with the environmental impacts of the construction of the powerline and the water pipeline. In addition, information is given about property rights and attaining permission to cross the property of proposed affected owners.
Mathematical and Numerical Analyses of Peridynamics for Multiscale Materials Modeling
Du, Qiang
2014-11-12
The rational design of materials, the development of accurate and efficient material simulation algorithms, and the determination of the response of materials to environments and loads occurring in practice all require an understanding of mechanics at disparate spatial and temporal scales. The project addresses mathematical and numerical analyses for material problems for which relevant scales range from those usually treated by molecular dynamics all the way up to those most often treated by classical elasticity. The prevalent approach towards developing a multiscale material model couples two or more well known models, e.g., molecular dynamics and classical elasticity, each of which is useful at a different scale, creating a multiscale multi-model. However, the challenges behind such a coupling are formidable and largely arise because the atomistic and continuum models employ nonlocal and local models of force, respectively. The project focuses on a multiscale analysis of the peridynamics materials model. Peridynamics can be used as a transition between molecular dynamics and classical elasticity so that the difficulties encountered when directly coupling those two models are mitigated. In addition, in some situations, peridynamics can be used all by itself as a material model that accurately and efficiently captures the behavior of materials over a wide range of spatial and temporal scales. Peridynamics is well suited to these purposes because it employs a nonlocal model of force, analogous to that of molecular dynamics; furthermore, at sufficiently large length scales and assuming smooth deformation, peridynamics can be approximated by classical elasticity. The project will extend the emerging mathematical and numerical analysis of peridynamics. One goal is to develop a peridynamics-enabled multiscale multi-model that potentially provides a new and more extensive mathematical basis for coupling classical elasticity and molecular dynamics, thus enabling next
Rapid installation of numerical models in multiple parent codes
Brannon, R.M.; Wong, M.K.
1996-10-01
A set of``model interface guidelines``, called MIG, is offered as a means to more rapidly install numerical models (such as stress-strain laws) into any parent code (hydrocode, finite element code, etc.) without having to modify the model subroutines. The model developer (who creates the model package in compliance with the guidelines) specifies the model`s input and storage requirements in a standardized way. For portability, database management (such as saving user inputs and field variables) is handled by the parent code. To date, NUG has proved viable in beta installations of several diverse models in vectorized and parallel codes written in different computer languages. A NUG-compliant model can be installed in different codes without modifying the model`s subroutines. By maintaining one model for many codes, MIG facilitates code-to-code comparisons and reduces duplication of effort potentially reducing the cost of installing and sharing models.
Numerical Modeling of Impact Initiation of High Explosives
Wu, C J; Piggott, T; Yoh, J; Reaugh, J
2006-05-31
We performed continuum mechanics simulations to examine the behavior of energetic materials in Ballistic Chamber Impact (BIC) experiments, using an Arbitrary Lagrangian-Eulerian code (ALE3D). Our simulations revealed that interface friction plays an important role in inducing the formation of shear bands, which result in 'hot spots' for ignition. The temperature localization during BIC impact was found to be significant in materials with high yield strength. In those materials, there are multiple locations inside shear bands can achieve temperatures exceeding the threshold temperature for reaction. In addition, we investigated the relevant parameters influencing the pressure profile of a BIC test by numerical analysis from a simple phenomenological model. To our surprise, we found that the peaks of BIC pressure profiles not only can be a result of multi-center chemical reactions, but can also arise from factors associated apparatus configuration.
Numerical studies of the radiant flash pyrolysis of cellulose
Kothari, V.; Antal, M.J.
1983-01-01
When biomass particles are heated very rapidly (>1000/sup 0/C/s) in an oxygen free environment, they undergo pyrolysis with the formation of little or no char. If concentrated solar energy is used to rapidly heat the particles, their temperature may exceed that of the surrounding gaseous environment by several hundred degrees Celsius when pyrolysis occurs. This ''two temperature'' effect gives rise to the formation of high yields of sirups from the pyrolyzing biomass. Interest in the selective formation of sirups during the radiative flash pyrolysis of biomass caused the authors to initiate numerical explorations of the combined effects of heat and mass transfer on the radiative flash pyrolysis phenomena. These explorations are described in this paper.
Three dimensional numerical simulations of the UPS-292-SC engine
O'Rourke, P.J.; Amsden, A.A.
1987-01-01
We present and analyze three-dimensional calculations of the spray, mixing and combustion in the UPS-292 stratified charge engine for three different operating conditions, corresponding to overall air-fuel ratios between 22.4 and 61.0. The numerical calculations are performed with KIVA, a multidimensional arbitrary-mesh, finite-difference hydrodynamics program for internal combustion engine applications. The calculations use a mesh of 10,000 computational cells, which conform to the shape of the piston bowl and cylinder and move to follow piston motion. Each operating condition is calculated from intake valve closure at 118/sup 0/ BTDC to 90/sup 0/ ATDC and requires approximately three hours of CRAY-XMP computer time.
The implementation of substation automation coordinated with numerical protection relaying
Welie, G. van; Carolin, T.
1994-12-31
During 1987 Eskom embarked on a process of defining user requirements in the area of substation control. This ultimately resulted in a project being established for the procurement and development of a new generation of substation control equipment. At the same time it was decided to establish a new generation of protection schemes for transmission substations, based on numerical protection relays. From the outset, a high degree of coordination was planned between the substation control and protection equipment. Development contracts were placed with suppliers during late 1990 for the protection schemes and during early 1991 for the substation control equipment. These contracts are nearing completion and the first large installations will commence during 1994. The Transmission Group has committed to employing this new technology in all new substations and all substations to be refurbished. This paper discusses the concept of coordinated substation control and protection and gives insight into implementation issues and functional compromises which had to be made to meet project deadlines.
Progress report on LBL's numerical modeling studies on Cerro Prieto
Halfman-Dooley, S.E.; Lippman, M.J.; Bodvarsson, G.S.
1989-04-01
An exploitation model of the Cerro Prieto geothermal system is needed to assess the energy capacity of the field, estimate its productive lifetime and develop an optimal reservoir management plan. The model must consider the natural state (i.e., pre-exploitation) conditions of the system and be able to predict changes in the reservoir thermodynamic conditions (and fluid chemistry) in response to fluid production (and injection). This paper discusses the results of a three-dimensional numerical simulation of the natural state conditions of the Cerro Prieto field and compares computed and observed pressure and temperature/enthalpy changes for the 1973--1987 production period. 16 refs., 24 figs., 2 tabs.
Numerical analysis of modified Central Solenoid insert design
Khodak, Andrei; Martovetsky, Nicolai; Smirnov, Aleksandre; Titus, Peter
2015-06-21
The United States ITER Project Office (USIPO) is responsible for fabrication of the Central Solenoid (CS) for ITER project. The ITER machine is currently under construction by seven parties in Cadarache, France. The CS Insert (CSI) project should provide a verification of the conductor performance in relevant conditions of temperature, field, currents and mechanical strain. The US IPO designed the CSI that will be tested at the Central Solenoid Model Coil (CSMC) Test Facility at JAEA, Naka. To validate the modified design we performed three-dimensional numerical simulations using coupled solver for simultaneous structural, thermal and electromagnetic analysis. Thermal and electromagneticmore » simulations supported structural calculations providing necessary loads and strains. According to current analysis design of the modified coil satisfies ITER magnet structural design criteria for the following conditions: (1) room temperature, no current, (2) temperature 4K, no current, (3) temperature 4K, current 60 kA direct charge, and (4) temperature 4K, current 60 kA reverse charge. Fatigue life assessment analysis is performed for the alternating conditions of: temperature 4K, no current, and temperature 4K, current 45 kA direct charge. Results of fatigue analysis show that parts of the coil assembly can be qualified for up to 1 million cycles. Distributions of the Current Sharing Temperature (TCS) in the superconductor were obtained from numerical results using parameterization of the critical surface in the form similar to that proposed for ITER. Lastly, special ADPL scripts were developed for ANSYS allowing one-dimensional representation of TCS along the cable, as well as three-dimensional fields of TCS in superconductor material. Published by Elsevier B.V.« less
Numerical analysis of modified Central Solenoid insert design
Khodak, Andrei; Martovetsky, Nicolai; Smirnov, Aleksandre; Titus, Peter
2015-06-21
The United States ITER Project Office (USIPO) is responsible for fabrication of the Central Solenoid (CS) for ITER project. The ITER machine is currently under construction by seven parties in Cadarache, France. The CS Insert (CSI) project should provide a verification of the conductor performance in relevant conditions of temperature, field, currents and mechanical strain. The US IPO designed the CSI that will be tested at the Central Solenoid Model Coil (CSMC) Test Facility at JAEA, Naka. To validate the modified design we performed three-dimensional numerical simulations using coupled solver for simultaneous structural, thermal and electromagnetic analysis. Thermal and electromagnetic simulations supported structural calculations providing necessary loads and strains. According to current analysis design of the modified coil satisfies ITER magnet structural design criteria for the following conditions: (1) room temperature, no current, (2) temperature 4K, no current, (3) temperature 4K, current 60 kA direct charge, and (4) temperature 4K, current 60 kA reverse charge. Fatigue life assessment analysis is performed for the alternating conditions of: temperature 4K, no current, and temperature 4K, current 45 kA direct charge. Results of fatigue analysis show that parts of the coil assembly can be qualified for up to 1 million cycles. Distributions of the Current Sharing Temperature (TCS) in the superconductor were obtained from numerical results using parameterization of the critical surface in the form similar to that proposed for ITER. Lastly, special ADPL scripts were developed for ANSYS allowing one-dimensional representation of TCS along the cable, as well as three-dimensional fields of TCS in superconductor material. Published by Elsevier B.V.
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CDIAC products include numeric data packages, publications, trend data, atlases, models, etc. and can be searched for by subject area, keywords, authors, product numbers, time periods, collection sites, spatial references, etc. Most data sets or packages, many with numerous data files, are free to download from CDIAC's ftp area. The collection provides access to the Oceanographic Numeric Data Packages (NDPs).
NUMERICAL STUDY OF THE VISHNIAC INSTABILITY IN SUPERNOVA REMNANTS
Michaut, C.; Cavet, C.; Bouquet, S. E.; Roy, F.; Nguyen, H. C.
2012-11-10
The Vishniac instability is thought to explain the complex structure of radiative supernova remnants in their Pressure-Driven Thin Shell (PDTS) phase after a blast wave (BW) has propagated from a central explosion. In this paper, the propagation of the BW and the evolution of the PDTS stage are studied numerically with the two-dimensional (2D) code HYDRO-MUSCL for a finite-thickness shell expanding in the interstellar medium (ISM). Special attention is paid to the adiabatic index, {gamma}, and three distinct values are taken for the cavity ({gamma}{sub 1}), the shell ({gamma}{sub 2}), and the ISM ({gamma}{sub 3}) with the condition {gamma}{sub 2} < {gamma}{sub 1}, {gamma}{sub 3}. This low value of {gamma}{sub 2} accounts for the high density in the shell achieved by a strong radiative cooling. Once the spherical background flow is obtained, the evolution of a 2D-axisymmetric perturbation is computed from the linear to the nonlinear regime. The overstable mechanism, previously demonstrated theoretically by E. T. Vishniac in 1983, is recovered numerically in the linear stage and is expected to produce and enhance anisotropies and clumps on the shock front, leading to the disruption of the shell in the nonlinear phase. The period of the increasing oscillations and the growth rate of the instability are derived from several points of view (the position of the perturbed shock front, mass fluxes along the shell, and density maps), and the most unstable mode differing from the value given by Vishniac is computed. In addition, the influence of several parameters (the Mach number, amplitude and wavelength of the perturbation, and adiabatic index) is examined and for wavelengths that are large enough compared to the shell thickness, the same conclusion arises: in the late stage of the evolution of the radiative supernova remnant, the instability is dampened and the angular initial deformation of the shock front is smoothed while the mass density becomes uniform with the
Liu, Fang; Lin, Lin; Vigil-Fowler, Derek; Lischner, Johannes; Kemper, Alexander F.; Sharifzadeh, Sahar; Jornada, Felipe H. da; Deslippe, Jack; Yang, Chao; and others
2015-04-01
We present a numerical integration scheme for evaluating the convolution of a Green's function with a screened Coulomb potential on the real axis in the GW approximation of the self energy. Our scheme takes the zero broadening limit in Green's function first, replaces the numerator of the integrand with a piecewise polynomial approximation, and performs principal value integration on subintervals analytically. We give the error bound of our numerical integration scheme and show by numerical examples that it is more reliable and accurate than the standard quadrature rules such as the composite trapezoidal rule. We also discuss the benefit of using different self energy expressions to perform the numerical convolution at different frequencies.
Numerical simulation of linear fiction welding (LFW) processes
Fratini, L.; La Spisa, D. [University of Palermo-Dept. of Industrial engineering (Italy)
2011-05-04
Solid state welding processes are becoming increasingly important due to a large number of advantages related to joining ''unweldable'' materials and in particular light weight alloys. Linear friction welding (LFW) has been used successfully to bond non-axisymmetric components of a range of materials including titanium alloys, steels, aluminum alloys, nickel, copper, and also dissimilar material combinations. The technique is useful in the research of quality of the joints and in reducing costs of components and parts of the aeronautic and automotive industries.LFW involves parts to be welded through the relative reciprocating motion of two components under an axial force. In such process the heat source is given by the frictional forces work decaying into heat determining a local softening of the material and proper bonding conditions due to both the temperature increase and the local pressure of the two edges to be welded. This paper is a comparative test between the numerical model in two dimensions, i.e. in plane strain conditions, and in three dimensions of a LFW process of AISI1045 steel specimens. It must be observed that the 3D model assures a faithful simulation of the actual threedimensional material flow, even if the two-dimensional simulation computational times are very short, a few hours instead of several ones as the 3D model. The obtained results were compared with experimental values found out in the scientific literature.
DRIVER TO SUPPORT USE OF NUMERICAL SIMULATION TOOLS
Energy Science and Technology Software Center (OSTI)
2001-02-13
UNIPACK is a computer interface that simplifies and enhances the use of numerical simulation tools to design a primary geometry and/or a forming die for a powder compact and/or to design the pressing process used to shape a powder by compaction. More particularly, it is an interface that utilizes predefined generic geometric configurations to simplify the use of finite element method modeling software to simply and more efficiently design: (1) the shape and size amore » powder compact; (2) a forming die to shape a powder compact; and/or (3) the pressing process used to form a powder compact. UNIPACK is a user interface for a predictive model for powder compaction that incorporates unprecedented flexibility to design powder press tooling and powder pressing processes. UNIPACK works with the Sandia National Laboratories (SNL) Engineering Analysis Cide Access System (SEACAS) to generate a finite element (FE) mesh and automatically perform a FE analysis of powder compaction. UNIPACK was developed to allow a non-expert with minimal training to quickly and easily design/construct a variable dimension component or die in real time on a desktop or laptop personal computer.« less
Numerical simulation of plasma heating of a composite powder particle
Demetriou, M.D.; Lavine, A.S.; Ghoniem, N.M.
1999-07-01
The use of fine composite powder particles (composed of a ceramic core and a metallic coating) in plasma spraying processes is desirable in developing thin film coatings that possess high abrasion as well as high fracture resistance. Quantitative knowledge of the thermal behavior of a composite particle in a plasma beam is essential in optimizing the process variables to achieve uniform melting of the coating material. In this work, a numerical model is developed to analyze the in-flight thermal behavior of a spherically symmetric WC-Co composite particle travelling in an argon arc-jet DC plasma under strongly unsteady plasma conditions. The model gives quantitative as well as qualitative information about the thermal response of the heated particle. The important features that are addressed are the temperature response of the particle; the history of the location of the melting and vaporization fronts; and the physical state of the particle at the end of its flight. For the conditions investigated, it was determined that the internal conduction resistance is negligible as compared to the net external resistance. However, the presence of the ceramic base was found to affect the transient heating process since its content in the particle composition determines the time constant of the process. Another interesting observation is that proper selection of the particle injection speed and injection location can be effective means for optimizing the heating process and achieving uniform melting of the coating material.
Advances in the numerical modeling of field-reversed configurations
Belova, Elena V.; Davidson, Ronald C.; Ji, Hantao; Yamada, Masaaki
2006-05-15
The field-reversed configuration (FRC) is a compact torus with little or no toroidal magnetic field. A theoretical understanding of the observed FRC equilibrium and stability properties presents significant challenges due to the high plasma beta, plasma flows, large ion gyroradius, and the stochasticity of the particle orbits. Advanced numerical simulations are generally required to describe and understand the detailed behavior of FRC plasmas. Results of such simulations are presented in this paper. It is shown that 3D nonlinear hybrid simulations using the HYM code [E. V. Belova et al., Phys. Plasmas 7, 4996 (2000)] reproduce all major experimentally observed stability properties of elongated (theta-pinch-formed) FRCs. Namely, the scaling of the growth rate of the n=1 tilt mode with the S*/E parameter (S* is the FRC kinetic parameter, E is elongation, and n is toroidal mode number), the nonlinear saturation of the tilt mode, ion toroidal spin-up, and the growth of the n=2 rotational mode have been demonstrated and studied in detail. The HYM code has also been used to study stability properties of FRCs formed by the counterhelicity spheromak merging method. A new stability regime has been found for FRCs with elongation E{approx}1, which requires a close-fitting conducting shell and energetic beam ion stabilization.
Comparison of numerical models of a pyrotechnic device
Pierce, K.G.
1986-01-01
The predictions of two numerical models of a hot-wire initiated pyrotechnic device are compared to each other and to experimental results. Both models employ finite difference approximations to the heat diffusion equation in cylindrical coordinates. The temperature dependence of the thermal properties of the pyrotechnic materials and of the bridgewire are modeled. An Arrhenius' model is used to describe the exothermic reaction in the powder. One model employs a single radial coordinate and predicts the radial temperature distribution in the bridgewire and surrounding powder mass. In addition to the radial coordinate, the other model also employs a longitudinal coordinate to predict the temperature distribution parallel to the axis of the bridgewire. The predictions of the two-dimensional model concerning the energy requirements for ignition and the energy losses from the ends of the bridgewire are presented. A comparison of the predictions of the two models and the development of thermal gradients are employed to define the regime where the assumption, in the one-dimensional model, of negligible heat transfer axial to the bridgewire does not lead to significant error. The general problems associated with predicting ignition from a diffusion model are also discussed.
Numerical calculation of two-phase turbulent jets
Saif, A.A.
1995-05-01
Two-phase turbulent round jets were numerically simulated using a multidimensional two-phase CFD code based on the two-fluid model. The turbulence phenomena were treated with the standard k-{epsilon} model. It was modified to take into account the additional dissipation of turbulent kinetic energy by the dispersed phase. Within the context of the two-fluid model it is more appropriate and physically justified to treat the diffusion by an interfacial force in the momentum equation. In this work, the diffusion force and the additional dissipation effect by the dispersed phase were modeled starting from the classical turbulent energy spectrum analysis. A cut-off frequency was proposed to decrease the dissipation effect by the dispersed phase when large size particles are introduced in the flow. The cut-off frequency combined with the bubble-induced turbulence effect allows for an increase in turbulence for large particles. Additional care was taken in choosing the right kind of experimental data from the literature so that a good separate effect test was possible for their models. The models predicted the experimental data very closely and they were general enough to predict extreme limit cases: water-bubble and air-droplet jets.
Advanced Numerical Methods and Software Approaches for Semiconductor Device Simulation
Carey, Graham F.; Pardhanani, A. L.; Bova, S. W.
2000-01-01
In this article we concisely present several modern strategies that are applicable to driftdominated carrier transport in higher-order deterministic models such as the driftdiffusion, hydrodynamic, and quantum hydrodynamic systems. The approaches include extensions of “upwind” and artificial dissipation schemes, generalization of the traditional Scharfetter – Gummel approach, Petrov – Galerkin and streamline-upwind Petrov Galerkin (SUPG), “entropy” variables, transformations, least-squares mixed methods and other stabilized Galerkin schemes such as Galerkin least squares and discontinuous Galerkin schemes. The treatment is representative rather than an exhaustive review and several schemes are mentioned only briefly with appropriate reference to the literature. Some of themore » methods have been applied to the semiconductor device problem while others are still in the early stages of development for this class of applications. We have included numerical examples from our recent research tests with some of the methods. A second aspect of the work deals with algorithms that employ unstructured grids in conjunction with adaptive refinement strategies. The full benefits of such approaches have not yet been developed in this application area and we emphasize the need for further work on analysis, data structures and software to support adaptivity. Finally, we briefly consider some aspects of software frameworks. These include dial-an-operator approaches such as that used in the industrial simulator PROPHET, and object-oriented software support such as those in the SANDIA National Laboratory framework SIERRA.« less
Numeric spectral radiation hydrodynamic calculations of supernova shock breakouts
Sapir, Nir; Halbertal, Dorri
2014-12-01
We present here an efficient numerical scheme for solving the non-relativistic one-dimensional radiation-hydrodynamics equations including inelastic Compton scattering, which is not included in most codes and is crucial for solving problems such as shock breakout. The devised code is applied to the problems of a steady-state planar radiation mediated shock (RMS) and RMS breakout from a stellar envelope. The results are in agreement with those of a previous work on shock breakout, in which Compton equilibrium between matter and radiation was assumed and the 'effective photon' approximation was used to describe the radiation spectrum. In particular, we show that the luminosity and its temporal dependence, the peak temperature at breakout, and the universal shape of the spectral fluence derived in this earlier work are all accurate. Although there is a discrepancy between the spectral calculations and the effective photon approximation due to the inaccuracy of the effective photon approximation estimate of the effective photon production rate, which grows with lower densities and higher velocities, the difference in peak temperature reaches only 30% for the most discrepant cases of fast shocks in blue supergiants. The presented model is exemplified by calculations for supernova 1987A, showing the detailed evolution of the burst spectrum. The incompatibility of the stellar envelope shock breakout model results with observed properties of X-ray flashes (XRFs) and the discrepancy between the predicted and observed rates of XRFs remain unexplained.
Robert L. Hellens, 1971 | U.S. DOE Office of Science (SC)
Reactors: In recognition of numerous pioneering contributions to the field of light water ... basis of design work on many large light water moderated power reactors and naval ...
Numerical investigation of spontaneous flame propagation under RCCI conditions
Bhagatwala, Ankit V; Sankaran, Ramanan; Kokjohn, Sage; Chen, Jacqueline H
2015-06-30
This paper presents results from one and two-dimensional direct numerical simulations under Reactivity Controlled Compression Ignition (RCCI) conditions of a primary reference fuel (PRF) mixture consisting of n-heptane and iso-octane. RCCI uses in-cylinder blending of two fuels with different autoignition characteristics to control combustion phasing and the rate of heat release. These simulations employ an improved model of compression heating through mass source/sink terms developed in a previous work by Bhagatwala et al. (2014), which incorporates feedback from the flow to follow a predetermined experimental pressure trace. Two-dimensional simulations explored parametric variations with respect to temperature stratification, pressure profiles andmore » n-heptane concentration. Furthermore, statistics derived from analysis of diffusion/reaction balances locally normal to the flame surface were used to elucidate combustion characteristics for the different cases. Both deflagration and spontaneous ignition fronts were observed to co-exist, however it was found that higher n-heptane concentration provided a greater degree of flame propagation, whereas lower n-heptane concentration (higher fraction of iso-octane) resulted in more spontaneous ignition fronts. A significant finding was that simulations initialized with a uniform initial temperature and a stratified n-heptane concentration field, resulted in a large fraction of combustion occurring through flame propagation. The proportion of spontaneous ignition fronts increased at higher pressures due to shorter ignition delay when other factors were held constant. For the same pressure and fuel concentration, the contribution of flame propagation to the overall combustion was found to depend on the level of thermal stratification, with higher initial temperature gradients resulting in more deflagration and lower gradients generating more ignition fronts. Statistics of ignition delay are computed to assess the Zel
Numerical investigation of spontaneous flame propagation under RCCI conditions
Bhagatwala, Ankit V; Sankaran, Ramanan; Kokjohn, Sage; Chen, Jacqueline H
2015-06-30
This paper presents results from one and two-dimensional direct numerical simulations under Reactivity Controlled Compression Ignition (RCCI) conditions of a primary reference fuel (PRF) mixture consisting of n-heptane and iso-octane. RCCI uses in-cylinder blending of two fuels with different autoignition characteristics to control combustion phasing and the rate of heat release. These simulations employ an improved model of compression heating through mass source/sink terms developed in a previous work by Bhagatwala et al. (2014), which incorporates feedback from the flow to follow a predetermined experimental pressure trace. Two-dimensional simulations explored parametric variations with respect to temperature stratification, pressure profiles and n-heptane concentration. Furthermore, statistics derived from analysis of diffusion/reaction balances locally normal to the flame surface were used to elucidate combustion characteristics for the different cases. Both deflagration and spontaneous ignition fronts were observed to co-exist, however it was found that higher n-heptane concentration provided a greater degree of flame propagation, whereas lower n-heptane concentration (higher fraction of iso-octane) resulted in more spontaneous ignition fronts. A significant finding was that simulations initialized with a uniform initial temperature and a stratified n-heptane concentration field, resulted in a large fraction of combustion occurring through flame propagation. The proportion of spontaneous ignition fronts increased at higher pressures due to shorter ignition delay when other factors were held constant. For the same pressure and fuel concentration, the contribution of flame propagation to the overall combustion was found to depend on the level of thermal stratification, with higher initial temperature gradients resulting in more deflagration and lower gradients generating more ignition fronts. Statistics of ignition delay are computed to assess the Zel
Numerical modeling of the SNS H{sup ?} ion source
Veitzer, Seth A.; Beckwith, Kristian R. C.; Kundrapu, Madhusudhan; Stoltz, Peter H.
2015-04-08
Ion source rf antennas that produce H- ions can fail when plasma heating causes ablation of the insulating coating due to small structural defects such as cracks. Reducing antenna failures that reduce the operating capabilities of the Spallation Neutron Source (SNS) accelerator is one of the top priorities of the SNS H- Source Program at ORNL. Numerical modeling of ion sources can provide techniques for optimizing design in order to reduce antenna failures. There are a number of difficulties in developing accurate models of rf inductive plasmas. First, a large range of spatial and temporal scales must be resolved in order to accurately capture the physics of plasma motion, including the Debye length, rf frequencies on the order of tens of MHz, simulation time scales of many hundreds of rf periods, large device sizes on tens of cm, and ion motions that are thousands of times slower than electrons. This results in large simulation domains with many computational cells for solving plasma and electromagnetic equations, short time steps, and long-duration simulations. In order to reduce the computational requirements, one can develop implicit models for both fields and particle motions (e.g. divergence-preserving ADI methods), various electrostatic models, or magnetohydrodynamic models. We have performed simulations using all three of these methods and have found that fluid models have the greatest potential for giving accurate solutions while still being fast enough to perform long timescale simulations in a reasonable amount of time. We have implemented a number of fluid models with electromagnetics using the simulation tool USim and applied them to modeling the SNS H- ion source. We found that a reduced, single-fluid MHD model with an imposed magnetic field due to the rf antenna current and the confining multi-cusp field generated increased bulk plasma velocities of > 200 m/s in the region of the antenna where ablation is often observed in the SNS source. We report
Improvements to the RELAP5-3D Nearly-Implicit Numerical Scheme
Richard A. Riemke; Walter L. Weaver; RIchard R. Schultz
2005-05-01
The RELAP5-3D computer program has been improved with regard to its nearly-implicit numerical scheme for twophase flow and single-phase flow. Changes were made to the nearly-implicit numerical scheme finite difference momentum equations as follows: (1) added the velocity flip-flop mass/energy error mitigation logic, (2) added the modified Henry-Fauske choking model, (3) used the new time void fraction in the horizontal stratification force terms and gravity head, and (4) used an implicit form of the artificial viscosity. The code modifications allow the nearly-implicit numerical scheme to be more implicit and lead to enhanced numerical stability.
Numerical method to test a theoretical model of the quantum interferen...
Office of Scientific and Technical Information (OSTI)
A numerical method is provided to fit the experimental conductivity to the complicated conductivity expression for the quantum interference effect of Anderson localization. This ...
Numerical Study of Velocity Shear Stabilization of 3D and Theoretical...
Office of Scientific and Technical Information (OSTI)
We studied the feasibility of resonantly driving GAMs in tokamaks. A numerical simulation ... Theoretical support was provided for the Maryland Centrifugal Experiment, funded in a ...
Numerical and experimental study of the weld joints formation in welding foam materials
Bezginov, Roman O. E-mail: rakrekt@mail.ru; Krektuleva, Raisa A. E-mail: rakrekt@mail.ru; Mishin, Mikhail A. E-mail: rakrekt@mail.ru; Cherepanov, Oleg I. Cherepanov, Roman O.
2014-11-14
A numerical analysis of fusion welding of steel- and aluminum-based foam materials is carried out. The schemes of the structured and stochastic pore distribution are considered. The research results were used to conduct the experiments which confirmed the reliability of the numerical calculations.
A High-Wavenumber Viscosity for High-Resolution Numerical Methods
Cook, A; Cabot, W H
2003-02-19
Numerical simulations of compressible flows are commonly based on the Euler equations when effects of viscosity are thought to be negligible. These equations admit singular solutions, even in cases where the initial and boundary conditions are smooth. So-called ''Euler solvers'' rely on numerical dissipation, explicitly or implicitly present in the scheme, to regularize the problem, such that physical solutions are selected.
On the Numerical Dispersion of Electromagnetic Particle-In-Cell Code : Finite Grid Instability
Meyers, Michael David; Huang, Chengkun; Zeng, Yong; Yi, Sunghwan; Albright, Brian James
2014-07-15
The Particle-In-Cell (PIC) method is widely used in relativistic particle beam and laser plasma modeling. However, the PIC method exhibits numerical instabilities that can render unphysical simulation results or even destroy the simulation. For electromagnetic relativistic beam and plasma modeling, the most relevant numerical instabilities are the finite grid instability and the numerical Cherenkov instability. We review the numerical dispersion relation of the electromagnetic PIC algorithm to analyze the origin of these instabilities. We rigorously derive the faithful 3D numerical dispersion of the PIC algorithm, and then specialize to the Yee FDTD scheme. In particular, we account for the manner in which the PIC algorithm updates and samples the fields and distribution function. Temporal and spatial phase factors from solving Maxwell's equations on the Yee grid with the leapfrog scheme are also explicitly accounted for. Numerical solutions to the electrostatic-like modes in the 1D dispersion relation for a cold drifting plasma are obtained for parameters of interest. In the succeeding analysis, we investigate how the finite grid instability arises from the interaction of the numerical 1D modes admitted in the system and their aliases. The most significant interaction is due critically to the correct representation of the operators in the dispersion relation. We obtain a simple analytic expression for the peak growth rate due to this interaction.
Daeva, S.G.; Setukha, A.V.
2015-03-10
A numerical method for solving a problem of diffraction of acoustic waves by system of solid and thin objects based on the reduction the problem to a boundary integral equation in which the integral is understood in the sense of finite Hadamard value is proposed. To solve this equation we applied piecewise constant approximations and collocation methods numerical scheme. The difference between the constructed scheme and earlier known is in obtaining approximate analytical expressions to appearing system of linear equations coefficients by separating the main part of the kernel integral operator. The proposed numerical scheme is tested on the solution of the model problem of diffraction of an acoustic wave by inelastic sphere.
Numerical thermalization in particle-in-cell simulations with Monte-Carlo collisions
Lai, P. Y.; Lin, T. Y.; Lin-Liu, Y. R.; Chen, S. H.
2014-12-15
Numerical thermalization in collisional one-dimensional (1D) electrostatic (ES) particle-in-cell (PIC) simulations was investigated. Two collision models, the pitch-angle scattering of electrons by the stationary ion background and large-angle collisions between the electrons and the neutral background, were included in the PIC simulation using Monte-Carlo methods. The numerical results show that the thermalization times in both models were considerably reduced by the additional Monte-Carlo collisions as demonstrated by comparisons with Turner's previous simulation results based on a head-on collision model [M. M. Turner, Phys. Plasmas 13, 033506 (2006)]. However, the breakdown of Dawson's scaling law in the collisional 1D ES PIC simulation is more complicated than that was observed by Turner, and the revised scaling law of the numerical thermalization time with numerical parameters are derived on the basis of the simulation results obtained in this study.
Numerical modeling of self-limiting and self-enhancing caprock...
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modeling of self-limiting and self-enhancing caprock alteration induced by CO2 storage in a depleted gas reservoir Citation Details In-Document Search Title: Numerical modeling of ...
Numerical research of the optimal control problem in the semi-Markov inventory model
Gorshenin, Andrey K.
2015-03-10
This paper is devoted to the numerical simulation of stochastic system for inventory management products using controlled semi-Markov process. The results of a special software for the systems research and finding the optimal control are presented.
Numerical simulation of tectonic plates motion and seismic process in Central Asia
Peryshkin, A. Yu.; Makarov, P. V. Eremin, M. O.
2014-11-14
An evolutionary approach proposed in [1, 2] combining the achievements of traditional macroscopic theory of solid mechanics and basic ideas of nonlinear dynamics is applied in a numerical simulation of present-day tectonic plates motion and seismic process in Central Asia. Relative values of strength parameters of rigid blocks with respect to the soft zones were characterized by the ? parameter that was varied in the numerical experiments within ? = 1.11.8 for different groups of the zonal-block divisibility. In general, the numerical simulations of tectonic block motion and accompanying seismic process in the model geomedium indicate that the numerical solutions of the solid mechanics equations characterize its deformation as a typical behavior of a nonlinear dynamic system under conditions of self-organized criticality.
A numerical study of crack initiation in a bcc iron system based...
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direct numerical results to the dynamic bifurcation theory R. Haberman, SIAM J. Appl. Math. 37, 69-106 (1979). Authors: Li, Xiantao, E-mail: xli@math.psu.edu 1 + Show Author...
Direct Numerical Simulation of Autoiginition of a Hydrogen Jet in a
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Preheated Cross Flow | Argonne Leadership Computing Facility Numerical Simulation of Autoiginition of a Hydrogen Jet in a Preheated Cross Flow Authors: Abdilghanie, A., Frouzakis, C.E., Fischer, P Autoignition of a nitrogen-diluted hydrogen mixture issuing from a round nozzle into a cross-flowing turbulent stream of preheated air flowing in a channel at a friction Reynolds number Re = 180 is inves- tigated via 3-D direct numerical simulations (DNS) at two crossflow stream temperatures (930
Advanced numerical methods for three dimensional two-phase flow calculations
Toumi, I.; Caruge, D.
1997-07-01
This paper is devoted to new numerical methods developed for both one and three dimensional two-phase flow calculations. These methods are finite volume numerical methods and are based on the use of Approximate Riemann Solvers concepts to define convective fluxes versus mean cell quantities. The first part of the paper presents the numerical method for a one dimensional hyperbolic two-fluid model including differential terms as added mass and interface pressure. This numerical solution scheme makes use of the Riemann problem solution to define backward and forward differencing to approximate spatial derivatives. The construction of this approximate Riemann solver uses an extension of Roe`s method that has been successfully used to solve gas dynamic equations. As far as the two-fluid model is hyperbolic, this numerical method seems very efficient for the numerical solution of two-phase flow problems. The scheme was applied both to shock tube problems and to standard tests for two-fluid computer codes. The second part describes the numerical method in the three dimensional case. The authors discuss also some improvements performed to obtain a fully implicit solution method that provides fast running steady state calculations. Such a scheme is not implemented in a thermal-hydraulic computer code devoted to 3-D steady-state and transient computations. Some results obtained for Pressurised Water Reactors concerning upper plenum calculations and a steady state flow in the core with rod bow effect evaluation are presented. In practice these new numerical methods have proved to be stable on non staggered grids and capable of generating accurate non oscillating solutions for two-phase flow calculations.
Elimination of numerical diffusion in 1 - phase and 2 - phase flows
Rajamaeki, M.
1997-07-01
The new hydraulics solution method PLIM (Piecewise Linear Interpolation Method) is capable of avoiding the excessive errors, numerical diffusion and also numerical dispersion. The hydraulics solver CFDPLIM uses PLIM and solves the time-dependent one-dimensional flow equations in network geometry. An example is given for 1-phase flow in the case when thermal-hydraulics and reactor kinetics are strongly coupled. Another example concerns oscillations in 2-phase flow. Both the example computations are not possible with conventional methods.
Experimental and numerical investigation of one-dimensional waterflood in porous reservoir
Hadia, N.; Chaudhari, L.; Mitra, Sushanta K.; Aggarwal, A.; Vinjamur, M.; Singh, R.
2007-11-15
Experimental and numerical investigation of relative permeability and oil recovery from the porous reservoir are described for short and long core samples. The relative permeability ratios, which are function of water saturation, obtained from laboratory core flooding experiments have been used for prediction of oil recovery through numerical simulation of non-dimensional Buckley-Leverett equation. The simulation results for oil recovery compared well with recovery results obtained from core flooding experiments. (author)
Numerical simulation of the flow in wire-wrapped pin bundles: Effect of
U.S. Department of Energy (DOE) all webpages (Extended Search)
pin-wire contact modeling | Argonne Leadership Computing Facility simulation of the flow in wire-wrapped pin bundles: Effect of pin-wire contact modeling Authors: Merzari, E., Smith, J.G., Tentner, A., Pointer, W.D., Fischer, P. The rapid advancement of numerical techniques and the availability of increasingly powerful supercomputers recently enabled scientists to use large eddy simulation (LES) to simulate numerically the flow in a full subassembly composed of wire-wrapped pins. Because of
Force-controlled absorption in a fully-nonlinear numerical wave tank
Spinneken, Johannes Christou, Marios; Swan, Chris
2014-09-01
An active control methodology for the absorption of water waves in a numerical wave tank is introduced. This methodology is based upon a force-feedback technique which has previously been shown to be very effective in physical wave tanks. Unlike other methods, an a-priori knowledge of the wave conditions in the tank is not required; the absorption controller being designed to automatically respond to a wide range of wave conditions. In comparison to numerical sponge layers, effective wave absorption is achieved on the boundary, thereby minimising the spatial extent of the numerical wave tank. In contrast to the imposition of radiation conditions, the scheme is inherently capable of absorbing irregular waves. Most importantly, simultaneous generation and absorption can be achieved. This is an important advance when considering inclusion of reflective bodies within the numerical wave tank. In designing the absorption controller, an infinite impulse response filter is adopted, thereby eliminating the problem of non-causality in the controller optimisation. Two alternative controllers are considered, both implemented in a fully-nonlinear wave tank based on a multiple-flux boundary element scheme. To simplify the problem under consideration, the present analysis is limited to water waves propagating in a two-dimensional domain. The paper presents an extensive numerical validation which demonstrates the success of the method for a wide range of wave conditions including regular, focused and random waves. The numerical investigation also highlights some of the limitations of the method, particularly in simultaneously generating and absorbing large amplitude or highly-nonlinear waves. The findings of the present numerical study are directly applicable to related fields where optimum absorption is sought; these include physical wavemaking, wave power absorption and a wide range of numerical wave tank schemes.
NUMERICAL VERIFICATION OF THE RELAP-7 CORE CHANNEL SINGLE-PHASE MODEL
Haihua Zhao; Ling Zou; Hongbin Zhang; Richard Martineau
2014-06-01
The RELAP-7 code is the next generation of nuclear reactor system safety analysis code being developed at the Idaho National Laboratory (INL). All the physics in RELAP-7 are fully coupled and the errors resulted from the traditional operator-splitting approach are eliminated. By using 2nd order methods in both time and space and eliminating operator-splitting errors, the numerical error of RELAP-7 can be minimized. Numerical verification is the process to verify the orders of numerical methods. It is an important part of modern verification and validation process. The core channel component in RELAP-7 is designed to simulate coolant flow as well as the conjugated heat transfer between coolant flow and the fuel rod. A special treatment at fuel centerline to avoid numerical singularity for the cylindrical heat conduction in the continuous finite element mesh is discussed. One steady state test case and one fast power up transient test case are utilized for the verification of the core channel model with single-phase flow. Analytical solution for the fuel pin temperature and figures of merit such as peak clad temperature and peak fuel temperature are used to define numerical errors. These cases prove that the mass and energy are well conserved and 2nd order convergence rates for both time and space are achieved in the core channel model.
Subtask 2.2 - Creating A Numerical Technique for Microseismic Data Inversion
Anastasia Dobroskok; Yevhen Holubnyak; James Sorensen
2009-05-01
Geomechanical and geophysical monitoring are the techniques which can complement each other and provide enhancement in the solutions of many problems of geotechnical engineering. One of the most promising geophysical techniques is passive seismic monitoring. The essence of the technique is recording the acoustic signals produced in the subsurface, either naturally or in response to human activity. The acoustic signals are produced by mechanical displacements on the contacts of structural elements (e.g., faults, boundaries of rock blocks, natural and induced fractures). The process can be modeled by modern numerical techniques developed in geomechanics. The report discusses a study that was aimed at the unification of the passive seismic monitoring and numerical modeling for the monitoring of the hydraulic fracture propagation. The approach adopted in the study consisted of numerical modeling of the seismicity accompanying hydraulic fracture propagation and defining seismic attributes and patterns characterizing the process and fracture parameters. Numerical experiments indicated that the spatial distribution of seismic events is correlated to geometrical parameters of hydrofracture. Namely, the highest density of the events is observed along fracture contour, and projection of the events to the fracture plane makes this effect most pronounced. The numerical experiments also showed that dividing the totality of the events into groups corresponding to the steps of fracture propagation allows for reconstructing the geometry of the resulting fracture more accurately than has been done in the majority of commercial applications.
Numerical approaches to combustion modeling. Progress in Astronautics and Aeronautics. Vol. 135
Oran, E.S.; Boris, J.P. )
1991-01-01
Various papers on numerical approaches to combustion modeling are presented. The topics addressed include; ab initio quantum chemistry for combustion; rate coefficient calculations for combustion modeling; numerical modeling of combustion of complex hydrocarbons; combustion kinetics and sensitivity analysis computations; reduction of chemical reaction models; length scales in laminar and turbulent flames; numerical modeling of laminar diffusion flames; laminar flames in premixed gases; spectral simulations of turbulent reacting flows; vortex simulation of reacting shear flow; combustion modeling using PDF methods. Also considered are: supersonic reacting internal flow fields; studies of detonation initiation, propagation, and quenching; numerical modeling of heterogeneous detonations, deflagration-to-detonation transition to reactive granular materials; toward a microscopic theory of detonations in energetic crystals; overview of spray modeling; liquid drop behavior in dense and dilute clusters; spray combustion in idealized configurations: parallel drop streams; comparisons of deterministic and stochastic computations of drop collisions in dense sprays; ignition and flame spread across solid fuels; numerical study of pulse combustor dynamics; mathematical modeling of enclosure fires; nuclear systems.
Amber Shrivastava; Brian Williams; Ali S. Siahpush; Bruce Savage; John Crepeau
2014-06-01
There have been significant efforts by the heat transfer community to investigate the melting phenomenon of materials. These efforts have included the analytical development of equations to represent melting, numerical development of computer codes to assist in modeling the phenomena, and collection of experimental data. The understanding of the melting phenomenon has application in several areas of interest, for example, the melting of a Phase Change Material (PCM) used as a thermal storage medium as well as the melting of the fuel bundle in a nuclear power plant during an accident scenario. The objective of this research is two-fold. First a numerical investigation, using computational fluid dynamics (CFD), of melting with internal heat generation for a vertical cylindrical geometry is presented. Second, to the best of authors knowledge, there are very limited number of engineering experimental results available for the case of melting with Internal Heat Generation (IHG). An experiment was performed to produce such data using resistive, or Joule, heating as the IHG mechanism. The numerical results are compared against the experimental results and showed favorable correlation. Uncertainties in the numerical and experimental analysis are discussed. Based on the numerical and experimental analysis, recommendations are made for future work.
A NUMERICAL STUDY OF DIFFUSIVE COSMIC-RAY TRANSPORT WITH ADIABATIC FOCUSING
Litvinenko, Yuri E.; Noble, P. L.
2013-03-01
Focused particle transport in a nonuniform large-scale magnetic field is investigated numerically in the case of isotropic pitch-angle scattering. Evolving particle density profiles and distribution moments are computed from solutions of a system of stochastic differential equations, equivalent to the original Fokker-Planck equation for the particle distribution. Conflicting analytical predictions for the transport coefficients in the diffusion limit, independently calculated by Beeck and Wibberenz and Shalchi, are compared with the numerical results. The reasons for the discrepancies among the analytical and numerical treatments, as well as the general limitations of the diffusion model, are discussed. The telegraph equation, derived in a higher-order expansion of the particle distribution function, is shown to describe the particle transport much more accurately than the diffusion model, especially ahead of a moving density pulse.
Formulation and numerical analysis of nonisothermal multiphase flow in porous media
Martinez, M.J.
1995-06-01
A mathematical formulation is presented for describing the transport of air, water and energy through porous media. The development follows a continuum mechanics approach. The theory assumes the existence of various average macroscopic variables which describe the state of the system. Balance equations for mass and energy are formulated in terms of these macroscopic variables. The system is supplemented with constitutive equations relating fluxes to the state variables, and with transport property specifications. Specification of various mixing rules and thermodynamic relations completes the system of equations. A numerical simulation scheme, employing the method of lines, is described for one-dimensional flow. The numerical method is demonstrated on sample problems involving nonisothermal flow of air and water. The implementation is verified by comparison with existing numerical solutions.
Numerical design of SiC bulk crystal growth for electronic applications
Wejrzanowski, T.; Grybczuk, M.; Kurzydlowski, K. J.; Tymicki, E.
2014-10-06
Presented study concerns numerical simulation of Physical Vapor Transport (PVT) growth of bulk Silicon Carbide (SiC) crystals. Silicon Carbide is a wide band gap semiconductor, with numerous applications due to its unique properties. Wider application of SiC is limited by high price and insufficient quality of the product. Those problems can be overcame by optimizing SiC production methods. Experimental optimization of SiC production is expensive because it is time consuming and requires large amounts of energy. Numerical modeling allows to learn more about conditions inside the reactor and helps to optimize the process at much lower cost. In this study several simulations of processes with different reactor geometries were presented along with discussion of reactor geometry influence on obtained monocrystal shape and size.
Numerical Simulation of Horizontal Continuous Casting Process of C194 Copper Alloy
Huang Guojie; Xie Shuisheng; Cheng Lei; Cheng Zhenkang [State Key Laboratory for Fabrication and Processing of Nonferrous Metals, Beijing General Research Institute for Non-ferrous Metals, China, 100088 (China)
2007-05-17
Horizontal Continuous Casting (H.C.C) is an important method to cast C194 copper ingot. In this paper, numerical simulation is adopted to investigate the casting process in order to optimize the H.C.C technical parameters, such as the casting temperature, casting speed and cooling intensity. According to the numerical results, the reasonable parameters are that the casting temperature is between 1383K{approx}1463K, the casting speed is between 7.2m/h{approx}10.8m/h and the speed of cooling water is between 3.6m/s{approx}4.6m/s. The results of numerical simulation provide the significant reference to the subsequent experiments.
Talamo, Alberto
2013-05-01
This study presents three numerical algorithms to solve the time dependent neutron transport equation by the method of the characteristics. The algorithms have been developed taking into account delayed neutrons and they have been implemented into the novel MCART code, which solves the neutron transport equation for two-dimensional geometry and an arbitrary number of energy groups. The MCART code uses regular mesh for the representation of the spatial domain, it models up-scattering, and takes advantage of OPENMP and OPENGL algorithms for parallel computing and plotting, respectively. The code has been benchmarked with the multiplication factor results of a Boiling Water Reactor, with the analytical results for a prompt jump transient in an infinite medium, and with PARTISN and TDTORT results for cross section and source transients. The numerical simulations have shown that only two numerical algorithms are stable for small time steps.
Dynamical properties of fractal networks: Scaling, numerical simulations, and physical realizations
Nakayama, T.; Yakubo, K. ); Orbach, R.L. )
1994-04-01
This article describes the advances that have been made over the past ten years on the problem of fracton excitations in fractal structures. The relevant systems to this subject are so numerous that focus is limited to a specific structure, the percolating network. Recent progress has followed three directions: scaling, numerical simulations, and experiment. In a happy coincidence, large-scale computations, especially those involving array processors, have become possible in recent years. Experimental techniques such as light- and neutron-scattering experiments have also been developed. Together, they form the basis for a review article useful as a guide to understanding these developments and for charting future research directions. In addition, new numerical simulation results for the dynamical properties of diluted antiferromagnets are presented and interpreted in terms of scaling arguments. The authors hope this article will bring the major advances and future issues facing this field into clearer focus, and will stimulate further research on the dynamical properties of random systems.
Effect of virtual mass on the characteristics and the numerical stability in two-phase flows
No, H.C.; Kazimi, M.S.
1981-04-01
It is known that the typical six equation two-fluid model of the two-phase flow possesses complex characteristics, exhibits unbounded instabilities in the short-wavelength limit and constitutes an ill-posed initial value problem. Among the suggestions to overcome these difficulties, one model for the virtual mass force terms were studied here, because the virtual mass represents real physical effects to accomplish the dissipation for numerical stability. It was found that the virtual mass has a profound effect upon the mathematical characteristic and numerical stability. Here a quantitative bound on the coefficient of the virtual mass terms was suggested for mathematical hyperbolicity and numerical stability. It was concluded that the finite difference scheme with the virtual mass model is restricted only by the convective stability conditions with the above suggested value.
Maes, G.J.
1993-10-01
This document contains the proceedings of the 62nd Interagency Manufacturing Operations Group (IMOG) Numerical Systems Group. Included are the minutes of the 61st meeting and the agenda for the 62nd meeting. Presentations at the meeting are provided in the appendices to this document. Presentations were: 1992 NSG Annual Report to IMOG Steering Committee; Charter for the IMOG Numerical Systems Group; Y-12 Coordinate Measuring Machine Training Project; IBH NC Controller; Automatically Programmed Metrology Update; Certification of Anvil-5000 for Production Use at the Y-12 Plant; Accord Project; Sandia National Laboratories {open_quotes}Accord{close_quotes}; Demo/Anvil Tool Path Generation 5-Axis; Demo/Video Machine/Robot Animation Dynamics; Demo/Certification of Anvil Tool Path Generation; Tour of the M-60 Inspection Machine; Distributed Numerical Control Certification; Spline Usage Method; Y-12 NC Engineering Status; and Y-12 Manufacturing CAD Systems.
Xing, Lu; Cullin, James; Spitler, Jeffery; Im, Piljae; Fisher, Daniel
2011-01-01
A new type of ground heat exchanger that utilizes the excavation often made for basements or foundations has been proposed as an alternative to conventional ground heat exchangers. This article describes a numerical model that can be used to size these foundation heat exchanger (FHX) systems. The numerical model is a two-dimensional finite-volume model that considers a wide variety of factors, such as soil freezing and evapotranspiration. The FHX numerical model is validated with one year of experimental data collected at an experimental house located near Oak Ridge, Tennessee. The model shows good agreement with the experimental data-heat pump entering fluid temperatures typically within 1 C (1.8 F) - with minor discrepancies due to approximations, such as constant moisture content throughout the year, uniform evapotranspiration over the seasons, and lack of ground shading in the model.
Black, Carrie; Ng, C. S.
2013-01-15
It has been demonstrated that in the presence of weak collisions, described by the Lenard-Bernstein (LB) collision operator, the Landau-damped solutions become true eigenmodes of the system and constitute a complete set [C.-S. Ng et al., Phys. Rev. Lett. 83, 1974 (1999) and C. S. Ng et al., Phys. Rev. Lett. 96, 065002 (2004)]. We present numerical results from an Eulerian Vlasov code that incorporates the Lenard-Bernstein collision operator [A. Lenard and I. B. Bernstein, Phys. Rev. 112, 1456 (1958)]. The effect of collisions on the numerical recursion phenomenon seen in Vlasov codes is discussed. The code is benchmarked against exact linear eigenmode solutions in the presence of weak collisions, and a spectrum of Landau-damped solutions is determined within the limits of numerical resolution. Tests of the orthogonality and the completeness relation are presented.
1980-12-01
The second quarterly technical progress report is presented for a program entitled, Application of Numerical Simulation Methodology to Automotive Combustion. The goal of the program is to develop, validate, demonstrate and apply a numerical simulation methodology for in-cylinder reactive flows in internal combustion engines. Previous work on this contract involved the initial development and validation of a finite difference based simulation model for time dependent axisymmetric flows which includes: a generalized coordinate system for arbitrary mesh design and treatment of complex and time dependent boundaries; multiple and interacting chemical species; coupled swirl flow velocity component; and two-equation turbulence closure. In its various stages of development, the model has been used to simulate numerous engine-related problems for validation and demonstration purposes. The technical effort during the current reporting period has concentrated on: reactive flow model development, test and data comparison studies; swirl flow simulations; and in-cylinder compression cycle flow simulations. Results of these studies are discussed.
Electromagnetic scattering problems -Numerical issues and new experimental approaches of validation
Geise, Robert; Neubauer, Bjoern; Zimmer, Georg
2015-03-10
Electromagnetic scattering problems, thus the question how radiated energy spreads when impinging on an object, are an essential part of wave propagation. Though the Maxwells differential equations as starting point, are actually quite simple,the integral formulation of an objects boundary conditions, respectively the solution for unknown induced currents can only be solved numerically in most cases.As a timely topic of practical importance the scattering of rotating wind turbines is discussed, the numerical description of which is still based on rigorous approximations with yet unspecified accuracy. In this context the issue of validating numerical solutions is addressed, both with reference simulations but in particular with the experimental approach of scaled measurements. For the latter the idea of an incremental validation is proposed allowing a step by step validation of required new mathematical models in scattering theory.
ARRAY OPTIMIZATION FOR TIDAL ENERGY EXTRACTION IN A TIDAL CHANNEL A NUMERICAL MODELING ANALYSIS
Yang, Zhaoqing; Wang, Taiping; Copping, Andrea
2014-04-18
This paper presents an application of a hydrodynamic model to simulate tidal energy extraction in a tidal dominated estuary in the Pacific Northwest coast. A series of numerical experiments were carried out to simulate tidal energy extraction with different turbine array configurations, including location, spacing and array size. Preliminary model results suggest that array optimization for tidal energy extraction in a real-world site is a very complex process that requires consideration of multiple factors. Numerical models can be used effectively to assist turbine siting and array arrangement in a tidal turbine farm for tidal energy extraction.
Numerical investigation of low-viscosity drop breakup in a contracting flow
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(Journal Article) | SciTech Connect Numerical investigation of low-viscosity drop breakup in a contracting flow Citation Details In-Document Search Title: Numerical investigation of low-viscosity drop breakup in a contracting flow Authors: Zhu, Guangdong ; Mammoli, Andrea Publication Date: 2011-03-01 OSTI Identifier: 1256411 Report Number(s): NREL/JA-550-51916 Journal ID: ISSN 1531-3492 DOE Contract Number: AC36-08GO28308 Resource Type: Journal Article Resource Relation: Journal Name:
Numerical Studies of Collective Phenomena in Two-Dimensional Electron and Cold Atom Systems
Rezayi, Edward
2013-07-25
Numerical calculations were carried out to investigate a number of outstanding questions in both two-dimensional electron and cold atom systems. These projects aimed to increase our understanding of the properties of and prospects for non-Abelian states in quantum Hall matter.
On Improving Analytical Models of Cosmic Reionization for Matching Numerical Simulations
Kaurov, Alexander A.
2016-01-01
The methods for studying the epoch of cosmic reionization vary from full radiative transfer simulations to purely analytical models. While numerical approaches are computationally expensive and are not suitable for generating many mock catalogs, analytical methods are based on assumptions and approximations. We explore the interconnection between both methods. First, we ask how the analytical framework of excursion set formalism can be used for statistical analysis of numerical simulations and visual representation of the morphology of ionization fronts. Second, we explore the methods of training the analytical model on a given numerical simulation. We present a new code which emerged from this study. Its main application is to match the analytical model with a numerical simulation. Then, it allows one to generate mock reionization catalogs with volumes exceeding the original simulation quickly and computationally inexpensively, meanwhile reproducing large scale statistical properties. These mock catalogs are particularly useful for CMB polarization and 21cm experiments, where large volumes are required to simulate the observed signal.
Numerical study of self modulation instability of 1 nC electron bunch at ATF
Fang Yun; Mori, Warren; Muggli, Patric
2012-12-21
The development of self-modulation instability (SMI) is investigated numerically for the 1 nC electron bunch available at Accelerator Test Facility (ATF) of Brookhaven National Laboratory (BNL). Possible experiment based on the simulation results is proposed. All the simulations are performed with the 2D-cylindrically symmetric particle-in-cell code.
Numerical simulation of transient, incongruent vaporization induced by high power laser
Tsai, C.H.
1981-01-01
A mathematical model and numerical calculations were developed to solve the heat and mass transfer problems specifically for uranum oxide subject to laser irradiation. It can easily be modified for other heat sources or/and other materials. In the uranium-oxygen system, oxygen is the preferentially vaporizing component, and as a result of the finite mobility of oxygen in the solid, an oxygen deficiency is set up near the surface. Because of the bivariant behavior of uranium oxide, the heat transfer problem and the oxygen diffusion problem are coupled and a numerical method of simultaneously solving the two boundary value problems is studied. The temperature dependence of the thermal properties and oxygen diffusivity, as well as the highly ablative effect on the surface, leads to considerable non-linearities in both the governing differential equations and the boundary conditions. Based on the earlier work done in this laboratory by Olstad and Olander on Iron and on Zirconium hydride, the generality of the problem is expanded and the efficiency of the numerical scheme is improved. The finite difference method, along with some advanced numerical techniques, is found to be an efficient way to solve this problem.
A novel method of including Landau level mixing in numerical studies of the quantum Hall effect
Wooten, Rachel; Quinn, John; Macek, Joseph
2013-12-04
Landau level mixing should influence the quantum Hall effect for all except the strongest applied magnetic fields. We propose a simple method for examining the effects of Landau level mixing by incorporating multiple Landau levels into the Haldane pseudopotentials through exact numerical diagonalization. Some of the resulting pseudopotentials for the lowest and first excited Landau levels will be presented.
1992-10-01
This appendix contains the numerically indexed bibliography for the complete group of reports on municipal solid waste management alternatives. The list references information on the following topics: mass burn technologies, RDF technologies, fluidized bed combustion, pyrolysis and gasification of MSW, materials recovery- recycling technologies, sanitary landfills, composting and anaerobic digestion of MSW.
Numerical errors in the presence of steep topography: analysis and alternatives
Lundquist, K A; Chow, F K; Lundquist, J K
2010-04-15
It is well known in computational fluid dynamics that grid quality affects the accuracy of numerical solutions. When assessing grid quality, properties such as aspect ratio, orthogonality of coordinate surfaces, and cell volume are considered. Mesoscale atmospheric models generally use terrain-following coordinates with large aspect ratios near the surface. As high resolution numerical simulations are increasingly used to study topographically forced flows, a high degree of non-orthogonality is introduced, especially in the vicinity of steep terrain slopes. Numerical errors associated with the use of terrainfollowing coordinates can adversely effect the accuracy of the solution in steep terrain. Inaccuracies from the coordinate transformation are present in each spatially discretized term of the Navier-Stokes equations, as well as in the conservation equations for scalars. In particular, errors in the computation of horizontal pressure gradients, diffusion, and horizontal advection terms have been noted in the presence of sloping coordinate surfaces and steep topography. In this work we study the effects of these spatial discretization errors on the flow solution for three canonical cases: scalar advection over a mountain, an atmosphere at rest over a hill, and forced advection over a hill. This study is completed using the Weather Research and Forecasting (WRF) model. Simulations with terrain-following coordinates are compared to those using a flat coordinate, where terrain is represented with the immersed boundary method. The immersed boundary method is used as a tool which allows us to eliminate the terrain-following coordinate transformation, and quantify numerical errors through a direct comparison of the two solutions. Additionally, the effects of related issues such as the steepness of terrain slope and grid aspect ratio are studied in an effort to gain an understanding of numerical domains where terrain-following coordinates can successfully be used and
STEM Educator Training by the U.S. Naval Academy
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Naval Station Newport Wind Resource Assessment. A Study Prepared...
U.S. Department of Energy (DOE) all webpages (Extended Search)
... wind speeds, energy production for a generic 1.5 MW wind turbine, and capacity factor. ... resource at the selected sites at NAVSTA Newport is sufficient for a wind turbine project. ...
Naval Petroleum Reserve No. 3 Disposition Decision Analysis and Timeline |
Energy Natural Phenomena Hazards DOE-STD 1020-2012 & DOE Handbook Mark Blackburn P.E. Office of Nuclear Facility Safety Programs AU, 32 October 21, 2014 Natural Phenomena Hazards DOE-STD 1020-2012 & DOE Handbook (267.25 KB) More Documents & Publications Application of Engineering and Technical Requirements for DOE Nuclear Facilities Standard Review Plan (SRP) DOE-STD-1020-2012 DOE Standard 1020 - Natural Phenomena Hazard analysis and Design Criteria for DOE Facilities
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Naval Petroleum Reserve No. 3 Site Environmental Report
2000-06-14
The CY1999 Site Environmental Report and Compliance Summary discusses environmental compliance activities for NPR-3 (Teapot Dome). All hazardous wastes that were stored in the hazardous waste accumulation at NPR-3 were removed in CY1999. NPR-3 maintains its status as a conditionally exempt small quantity generator. Hydrogen sulfide (H2S) flares have not operated at NPR-3 since 1996; monitoring of H2S indicates readings well below limits. All underground storage tanks were removed in 1998. Wastewater samples were in compliance with applicable standards.
Commander, Naval Base ATTN: Ms. Cheryl Barnett Building N-26
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As we discussed, in July 1956, the Atomic Energy Commission (a DOE predecessor) or its contractors conducted a fire training demonstration of uranium fire fighting techniques at ...
Naval Nuclear Propulsion Plants | National Nuclear Security Administra...
National Nuclear Security Administration (NNSA)
use a pressurized-water reactor design that has two basic systems: the primary system and the secondary system. The primary system circulates ordinary water in an all-welded, ...
Naval Support Activity (NSA) in Bethesda Employment Education Fair
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Location: NSA Bethesda Fitness Center (Gymnasium, Bldg 17), 8901 Wisconsin Ave., Bethesda, MD 20889Attendees: Donna Friend (HC) and Rauland Sharp (HC)POC: Donna FriendWebsite: http://bit.ly/1yTjTNu
DOE - Office of Legacy Management -- Naval Oil Shale Reserves...
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From the early 1940's through the early 1980's, the U.S. Department of Energy (DOE) conducted oil shale retort experiments in the Green River geologic formation. These retort ...
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a small oil field and covers approximately 9400 acres. Environmental remediation efforts are underway and a portion of the site is being used to test exploration and production ...
DOE - Office of Legacy Management -- Naval Office at the University...
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CHEMICAL TRANSPORT IN A FISSURED BOCK: VERIFICATION OF A NUMERICAL MODEL
Rasmuson, A.; Narasimhan, T.N.; Neretnieks, I.
1982-04-01
Numerical models for simulating chemical transport in fissured rocks constitute powerful tools for evaluating the acceptability of geological nuclear waste repositories. Due to the very long-term, high toxicity of some nuclear waste products, the models are required to predict, in certain cases, the spatial and temporal distribution of chemical concentration less than 0.001% of the concentration released from the repository. Whether numerical models can provide such accuracies is a major question addressed in the present work. To this end, we have verified a numerical model, TRUMP, which solves the advective diffusion equation in general three dimensions with or without decay and source terms. The method is based on an integrated finite-difference approach. The model was verified against known analytic solution of the one-dimensional advection-diffusion problem as well as the problem of advection-diffusion in a system of parallel fractures separated by spherical particles. The studies show that as long as the magnitude of advectance is equal to or less than that of conductance for the closed surface bounding any volume element in the region (that is, numerical Peclet number <2), the numerical method can indeed match the analytic solution within errors of ±10{sup -3} % or less. The realistic input parameters used in the sample calculations suggest that such a range of Peclet numbers is indeed likely to characterize deep groundwater systems in granitic and ancient argillaceous systems. Thus TRUMP in its present form does provide a viable tool for use in nuclear waste evaluation studies. A sensitivity analysis based on the analytic solution suggests that the errors in prediction introduced due to uncertainties in input parameters is likely to be larger than the computational inaccuracies introduced by the numerical model. Currently, a disadvantage in the TRUMP model is that the iterative method of solving the set of simultaneous equations is rather slow when time
Bowman, D.; DeWaters, J.; Smith, J.; Snow, S.; Thomas, R.
1995-08-01
The approach for conducting a Pollution Prevention Opportunity Assessment (PPOA) at the Norfolk NAS is described along with background information about the site. Section 2 provides background information related to cooling tower operations and water treatment processes. Section 3 describes the current cooling tower activities and operations that were observed during the NAS site visit. Possible alternative practices for minimizing these wastes are discussed in Section 4. Recommendations on potential follow-up activities are also included in Section 4. Appendices include PPOA worksheets (Appendix A), National Pollutant Discharge Elimination Systems (NPDES) discharge limits (Appendix B), discharge data (Appendix C), material safety data sheets (MSDS) (Appendix D), the Hampton Roads Sanitation District Cooling Tower Waste Discharge Policy with Industrial Wastewater Pollutant Limitations and Discharge Requirements (Appendix E), and the MSDS for DIAS-Aid Tower Treatment XP-300 (Appendix F).
Rider, William; Kamm, J. R.; Tomkins, C. D.; Zoldi, C. A.; Prestridge, K. P.; Marr-Lyon, M.; Rightley, P. M.; Benjamin, R. F.
2002-01-01
We consider the detailed structures of mixing flows for Richtmyer-Meshkov experiments of Prestridge et al. [PRE 00] and Tomkins et al. [TOM 01] and examine the most recent measurements from the experimental apparatus. Numerical simulations of these experiments are performed with three different versions of high resolution finite volume Godunov methods. We compare experimental data with simulations for configurations of one and two diffuse cylinders of SF{sub 6} in air using integral measures as well as fractal analysis and continuous wavelet transforms. The details of the initial conditions have a significant effect on the computed results, especially in the case of the double cylinder. Additionally, these comparisons reveal sensitive dependence of the computed solution on the numerical method.
Analysis of the flamelet concept in the numerical simulation of laminar partially premixed flames
Consul, R.; Oliva, A.; Perez-Segarra, C.D.; Carbonell, D.; de Goey, L.P.H.
2008-04-15
The aim of this work is to analyze the application of flamelet models based on the mixture fraction variable and its dissipation rate to the numerical simulation of partially premixed flames. Although the main application of these models is the computation of turbulent flames, this work focuses on the performance of flamelet concept in laminar flame simulations removing, in this way, turbulence closure interactions. A well-known coflow methane/air laminar flame is selected. Five levels of premixing are taken into account from an equivalence ratio {phi}={infinity} (nonpremixed) to {phi}=2.464. Results obtained using the flamelet approaches are compared to data obtained from the detailed solution of the complete transport equations using primitive variables. Numerical simulations of a counterflow flame are also presented to support the discussion of the results. Special emphasis is given to the analysis of the scalar dissipation rate modeling. (author)
Lavergne, F.; Sab, K.; Sanahuja, J.; Bornert, M.; Toulemonde, C.
2015-05-15
Prestress losses due to creep of concrete is a matter of interest for long-term operations of nuclear power plants containment buildings. Experimental studies by Granger (1995) have shown that concretes with similar formulations have different creep behaviors. The aim of this paper is to numerically investigate the effect of size distribution and shape of elastic inclusions on the long-term creep of concrete. Several microstructures with prescribed size distribution and spherical or polyhedral shape of inclusions are generated. By using the 3D numerical homogenization procedure for viscoelastic microstructures proposed by Šmilauer and Bažant (2010), it is shown that the size distribution and shape of inclusions have no measurable influence on the overall creep behavior. Moreover, a mean-field estimate provides close predictions. An Interfacial Transition Zone was introduced according to the model of Nadeau (2003). It is shown that this feature of concrete's microstructure can explain differences between creep behaviors.
François, Marianne M.
2015-05-28
A review of recent advances made in numerical methods and algorithms within the volume tracking framework is presented. The volume tracking method, also known as the volume-of-fluid method has become an established numerical approach to model and simulate interfacial flows. Its advantage is its strict mass conservation. However, because the interface is not explicitly tracked but captured via the material volume fraction on a fixed mesh, accurate estimation of the interface position, its geometric properties and modeling of interfacial physics in the volume tracking framework remain difficult. Several improvements have been made over the last decade to address these challenges.more » In this study, the multimaterial interface reconstruction method via power diagram, curvature estimation via heights and mean values and the balanced-force algorithm for surface tension are highlighted.« less
Verifying the error bound of numerical computation implemented in computer systems
Sawada, Jun
2013-03-12
A verification tool receives a finite precision definition for an approximation of an infinite precision numerical function implemented in a processor in the form of a polynomial of bounded functions. The verification tool receives a domain for verifying outputs of segments associated with the infinite precision numerical function. The verification tool splits the domain into at least two segments, wherein each segment is non-overlapping with any other segment and converts, for each segment, a polynomial of bounded functions for the segment to a simplified formula comprising a polynomial, an inequality, and a constant for a selected segment. The verification tool calculates upper bounds of the polynomial for the at least two segments, beginning with the selected segment and reports the segments that violate a bounding condition.
Proceedings of the Numerical Modeling for Underground Nuclear Test Monitoring Symposium
Taylor, S.R.; Kamm, J.R.
1993-11-01
The purpose of the meeting was to discuss the state-of-the-art in numerical simulations of nuclear explosion phenomenology with applications to test ban monitoring. We focused on the uniqueness of model fits to data, the measurement and characterization of material response models, advanced modeling techniques, and applications of modeling to monitoring problems. The second goal of the symposium was to establish a dialogue between seismologists and explosion-source code calculators. The meeting was divided into five main sessions: explosion source phenomenology, material response modeling, numerical simulations, the seismic source, and phenomenology from near source to far field. We feel the symposium reached many of its goals. Individual papers submitted at the conference are indexed separately on the data base.
Mikellides, Ioannis G.; Goebel, Dan M.; Snyder, John Steven; Katz, Ira; Herman, Daniel A.
2010-12-01
Numerical simulations of neutralizer hollow cathodes at various operating conditions and orifice sizes are presented. The simulations were performed using a two-dimensional axisymmetric model that solves numerically an extensive system of conservation laws for the partially ionized gas in these devices. The results for the plasma are compared directly with Langmuir probe measurements. The computed keeper voltages are also compared with the observed values. Whenever model inputs and/or specific physics of the cathode discharge were uncertain or unknown additional sensitivity calculations have been performed to quantify the uncertainties. The model has also been employed to provide insight into recent ground test observations of the neutralizer cathode in NASA's evolutionary xenon thruster. It is found that a likely cause of the observed keeper voltage drop in a long duration test of the engine is cathode orifice erosion.
Rossi, Tuomas P. Sakko, Arto; Puska, Martti J.; Lehtola, Susi; Nieminen, Risto M.
2015-03-07
We present an approach for generating local numerical basis sets of improving accuracy for first-principles nanoplasmonics simulations within time-dependent density functional theory. The method is demonstrated for copper, silver, and gold nanoparticles that are of experimental interest but computationally demanding due to the semi-core d-electrons that affect their plasmonic response. The basis sets are constructed by augmenting numerical atomic orbital basis sets by truncated Gaussian-type orbitals generated by the completeness-optimization scheme, which is applied to the photoabsorption spectra of homoatomic metal atom dimers. We obtain basis sets of improving accuracy up to the complete basis set limit and demonstrate that the performance of the basis sets transfers to simulations of larger nanoparticles and nanoalloys as well as to calculations with various exchange-correlation functionals. This work promotes the use of the local basis set approach of controllable accuracy in first-principles nanoplasmonics simulations and beyond.
Numerical Simulation of Combustion and Rotor-Stator Interaction in a Turbine Combustor
Isvoranu, Dragos D.; Cizmas, Paul G. A.
2003-01-01
This article presents the development of a numerical algorithm for the computation of flow and combustion in a turbine combustor. The flow and combustion are modeled by the Reynolds-averaged Navier-Stokes equations coupled with the species-conservation equations. The chemistry model used herein is a two-step, global, finite-rate combustion model for methane and combustion gases. The governing equations are written in the strong conservation form and solved using a fully implicit, finite-difference approximation. The gas dynamics and chemistry equations are fully decoupled. A correction technique has been developed to enforce the conservation of mass fractions. The numerical algorithm developed herein has beenmore » used to investigate the flow and combustion in a one-stage turbine combustor.« less
Numerical Investigation of Flapwise-Torsional Vibration Model of a Smart Section Blade with Microtab
Li, Nailu; Balas, Mark J.; Yang, Hua; Jiang, Wei; Magar, Kaman T.
2015-01-01
This study presents a method to develop an aeroelastic model of a smart section blade equipped with microtab. The model is suitable for potential passive vibration control study of the blade section in classic flutter. Equations of the model are described by the nondimensional flapwise and torsional vibration modes coupled with the aerodynamic model based on the Theodorsen theory and aerodynamic effects of the microtab based on the wind tunnel experimental data. The aeroelastic model is validated using numerical data available in the literature and then utilized to analyze the microtab control capability on flutter instability case and divergence instabilitymore » case. The effectiveness of the microtab is investigated with the scenarios of different output controllers and actuation deployments for both instability cases. The numerical results show that the microtab can effectively suppress both vibration modes with the appropriate choice of the output feedback controller.« less
Numerical analysis for high-efficiency GaAs solar cells fabricated on Si substrates
Yamaguchi, M.; Amano, C.; Itoh, Y.
1989-07-15
This paper describes some recent developments in GaAs thin-film solar cells fabricated on Si substrates by metalorganic chemical vapor deposition and numerically analyzes them.GaAs solar cells with efficiency of more than 18% are successfully fabricated on Si substrates by reducing the dislocation density. Photovoltaic properties of GaAs/Si cells are analyzed by considering the effect of nonuniform dislocation distribution on recombination properties of GaAs thin films on Si substrates. Numerical analysis shows that the effect of majority-carrier trapping must be considered. High efficiency GaAs solar cells with total-area efficiency of over 20% on Si substrates can be realized if dislocation density can be reduced to less than 5/times/10/sup 5/ cm/sup /minus/2/.
Holladay, Jamelyn D.; Wang, Yong
2015-05-01
Microscale (<5W) reformers for hydrogen production have been investigated for over a decade. These devices are intended to provide hydrogen for small fuel cells. Due to the reformer’s small size, numerical simulations are critical to understand heat and mass transfer phenomena occurring in the systems. This paper reviews the development of the numerical codes and details the reaction equations used. The majority of the devices utilized methanol as the fuel due to methanol’s low reforming temperature and high conversion, although, there are several methane fueled systems. As computational power has decreased in cost and increased in availability, the codes increased in complexity and accuracy. Initial models focused on the reformer, while more recently, the simulations began including other unit operations such as vaporizers, inlet manifolds, and combustors. These codes are critical for developing the next generation systems. The systems reviewed included, plate reactors, microchannel reactors, annulus reactors, wash-coated, packed bed systems.
Numerical study of a matrix-free trust-region SQP method for equality constrained optimization.
Heinkenschloss, Matthias; Ridzal, Denis; Aguilo, Miguel Antonio
2011-12-01
This is a companion publication to the paper 'A Matrix-Free Trust-Region SQP Algorithm for Equality Constrained Optimization' [11]. In [11], we develop and analyze a trust-region sequential quadratic programming (SQP) method that supports the matrix-free (iterative, in-exact) solution of linear systems. In this report, we document the numerical behavior of the algorithm applied to a variety of equality constrained optimization problems, with constraints given by partial differential equations (PDEs).
Numerical simulations of stripping effects in high-intensity hydrogen ion linacs
Carneiro, J.-P.; Mustapha, B.; Ostroumov, P.N.; /Argonne
2008-12-01
Numerical simulations of H{sup -} stripping losses from blackbody radiation, electromagnetic fields, and residual gas have been implemented into the beam dynamics code TRACK. Estimates of the stripping losses along two high-intensity H{sup -} linacs are presented: the Spallation Neutron Source linac currently being operated at Oak Ridge National Laboratory and an 8 GeV superconducting linac currently being designed at Fermi National Accelerator Laboratory.
Numerical simulations of impulsively generated Alfvn waves in solar magnetic arcades
Chmielewski, P.; Murawski, K.; Musielak, Z. E.; Srivastava, A. K.
2014-09-20
We perform numerical simulations of impulsively generated Alfvn waves in an isolated solar arcade, which is gravitationally stratified and magnetically confined. We study numerically the propagation of Alfvn waves along the magnetic structure that extends from the lower chromosphere, where the waves are generated, to the solar corona, and analyze the influence of the arcade size and the width of the initial pulses on the wave propagation and reflection. Our model of the solar atmosphere is constructed by adopting the temperature distribution based on the semi-empirical VAL-C model and specifying the curved magnetic field lines that constitute the asymmetric magnetic arcade. The propagation and reflection of Alfvn waves in this arcade is described by 2.5-dimensional magnetohydrodynamic equations that are numerically solved by the FLASH code. Our numerical simulations reveal that the Alfvn wave amplitude decreases as a result of a partial reflection of Alfvn waves in the solar transition region, and that the waves that are not reflected leak through the transition region and reach the solar corona. We also find the decrement of the attenuation time of Alfvn waves for wider initial pulses. Moreover, our results show that the propagation of Alfvn waves in the arcade is affected by the spatial dependence of the Alfvn speed, which leads to phase mixing that is stronger for more curved and larger magnetic arcades. We discuss the processes that affect the Alfvn wave propagation in an asymmetric solar arcade and conclude that besides phase mixing in the magnetic field configuration, the plasma properties of the arcade, the size of the initial pulse, and the structure of the solar transition region all play a vital role in the Alfvn wave propagation.
Numerical simulations of a vertical tail of a commercial aircraft with
U.S. Department of Energy (DOE) all webpages (Extended Search)
active flow control | Argonne Leadership Computing Facility simulations of a vertical tail of a commercial aircraft with active flow control Authors: Rasquin, M., Martin, J., Jansen, K. A series of numerical simulations of a realistic vertical tail of a commercial aircraft, with a tapered swept stabilizer and a rudder, is considered in this work with application of flow control. Flow control is known to have the capacity to augment the streamwise momentum near the rudder suction peak where
Theoretical, numerical and experimental investigation of centrifugal pumps in reverse operation
Derakhshan, Shahram; Nourbakhsh, Ahmad
2008-09-15
When a pump works as a turbine, its hydraulic behavior will be changed. Several methods have been developed to predict the best efficiency of pumps running as turbines but their results are not in good coincidence with experimental data for all pumps. Therefore, study and investigation of hydraulic behavior of pumps in reverse operation can be useful. In this study, the best efficiency point of an industrial centrifugal pump running as turbine was achieved using a theoretical analysis. This method tries to estimate hydraulic components of reverse (turbine) mode using direct (pump) mode. In the next step, the pump was simulated in direct and reverse modes by computational fluid dynamics. 3D full Navier-Stokes equations were solved using FineTurbo V.7 flow solver. Using numerical results, complete characteristic curves of the pump in direct and reverse modes were obtained. For experimental verification of theoretical and numerical results, the pump was tested as a turbine in a test rig. All required parameters were measured to achieve complete characteristic curves of the reverse pump. The theoretical and numerical results were compared with experimental data and some other methods. (author)
Solving the Bateman equations in CASMO5 using implicit ode numerical methods for stiff systems
Hykes, J. M.; Ferrer, R. M.
2013-07-01
The Bateman equations, which describe the transmutation of nuclides over time as a result of radioactive decay, absorption, and fission, are often numerically stiff. This is especially true if short-lived nuclides are included in the system. This paper describes the use of implicit numerical methods for o D Es applied to the stiff Bateman equations, specifically employing the Backward Differentiation Formulas (BDF) form of the linear multistep method. As is true in other domains, using an implicit method removes or lessens the (sometimes severe) step-length constraints by which explicit methods must abide. To gauge its accuracy and speed, the BDF method is compared to a variety of other solution methods, including Runge-Kutta explicit methods and matrix exponential methods such as the Chebyshev Rational Approximation Method (CRAM). A preliminary test case was chosen as representative of a PWR lattice depletion step and was solved with numerical libraries called from a Python front-end. The Figure of Merit (a combined measure of accuracy and efficiency) for the BDF method was nearly identical to that for CRAM, while explicit methods and other matrix exponential approximations trailed behind. The test case includes 319 nuclides, in which the shortest-lived nuclide is {sup 98}Nb with a half-life of 2.86 seconds. Finally, the BDF and CRAM methods were compared within CASMO5, where CRAM had a FOM about four times better than BDF, although the BDF implementation was not fully optimized. (authors)
Figueroa, Aldo [Facultad de Ciencias, Universidad Autnoma del Estado de Morelos, Cuernavaca, Morelos 62209 (Mexico)] [Facultad de Ciencias, Universidad Autnoma del Estado de Morelos, Cuernavaca, Morelos 62209 (Mexico); Meunier, Patrice; Villermaux, Emmanuel [Aix-Marseille Univ., CNRS, Centrale Marseille, IRPHE, Marseille F-13384 (France)] [Aix-Marseille Univ., CNRS, Centrale Marseille, IRPHE, Marseille F-13384 (France); Cuevas, Sergio; Ramos, Eduardo [Instituto de Energas Renovables, Universidad Nacional Autnoma de Mxico, A.P. 34, Temixco, Morelos 62580 (Mexico)] [Instituto de Energas Renovables, Universidad Nacional Autnoma de Mxico, A.P. 34, Temixco, Morelos 62580 (Mexico)
2014-01-15
We present a combination of experiment, theory, and modelling on laminar mixing at large Pclet number. The flow is produced by oscillating electromagnetic forces in a thin electrolytic fluid layer, leading to oscillating dipoles, quadrupoles, octopoles, and disordered flows. The numerical simulations are based on the Diffusive Strip Method (DSM) which was recently introduced (P. Meunier and E. Villermaux, The diffusive strip method for scalar mixing in two-dimensions, J. Fluid Mech. 662, 134172 (2010)) to solve the advection-diffusion problem by combining Lagrangian techniques and theoretical modelling of the diffusion. Numerical simulations obtained with the DSM are in reasonable agreement with quantitative dye visualization experiments of the scalar fields. A theoretical model based on log-normal Probability Density Functions (PDFs) of stretching factors, characteristic of homogeneous turbulence in the Batchelor regime, allows to predict the PDFs of scalar in agreement with numerical and experimental results. This model also indicates that the PDFs of scalar are asymptotically close to log-normal at late stages, except for the large concentration levels which correspond to low stretching factors.
A numerical and experimental investigation of premixed methane-air flame transient response
Habib N. Najm; Phillip H. Paul; Omar M. Knio; Andrew McIlroy
2000-01-06
The authors report the results of a numerical and experimental investigation of the response of premixed methane-air flames to transient strain-rate disturbances induced by a two-dimensional counter-rotating vortex-pair. The numerical and experimental time histories of flow and flame evolution are matched over a 10 ms interaction time. Measurements and computations of CH and OH peak data evolution are reported, and found to indicate mis-prediction of the flame time scales in the numerical model. Qualitative transient features of OH at rich conditions are not predicted in the computations. On the other hand, evolution of computed and measured normalized HCO fractions are in agreement. The computed CH{sub 3}O response exhibits a strong transient driven by changes to internal flame structure, namely temperature profile steepening, induced by the flow field. Steady state experimental PLIF CH{sub 3}O data is reported, but experimental transient CH{sub 3}O data is not available. The present analysis indicates that the flame responds at time scales that are quite distinct from ``propagation'' time scale derived from flame thickness and burning speed. Evidently, these propagation time scales are not adequate for characterizing the transient flame response.
Bae, Y. Y.; Hong, S. D.; Kim, Y. W.
2012-07-01
A number of computational works have been performed so far for the simulation of heat transfer in a supercritical fluid. The simulations, however, faced a lot of difficulties when heat transfer deteriorates due either to buoyancy or by acceleration. When the bulk temperature approaches the pseudo-critical temperature the fluid experiences a severe axial density gradient on top of a severe radial one. Earlier numerical calculations showed, without exception, unrealistic over-predictions, as soon as the bulk temperature exceeded the pseudo-critical temperature. The over-predictions might have been resulted from an inapplicability of widely-used turbulence models. One of the major causes for the difficulties may probably be an assumption of a constant turbulent Prandtl number. Recent research, both numerical and experimental, indicates that the turbulent Prandtl number is never a constant when the gradient of physical properties is significant. This paper describes the applicability of a variable turbulent Prandtl number to the numerical simulation of heat transfer in supercritical fluids flowing in narrow vertical tubes. (authors)
Combined experimental and numerical evaluation of a prototype nano-PCM enhanced wallboard
Biswas, Kaushik; LuPh.D., Jue; Soroushian, Parviz; Shrestha, Som S
2014-01-01
In the United States, forty-eight (48) percent of the residential end-use energy consumption is spent on space heating and air conditioning. Reducing envelope-generated heating and cooling loads through application of phase change material (PCM)-enhanced building envelopes can facilitate maximizing the energy efficiency of buildings. Combined experimental testing and numerical modeling of PCM-enhanced envelope components are two important aspects of the evaluation of their energy benefits. An innovative phase change material (nano-PCM) was developed with PCM encapsulated with expanded graphite (interconnected) nanosheets, which is highly conductive for enhanced thermal storage and energy distribution, and is shape-stable for convenient incorporation into lightweight building components. A wall with cellulose cavity insulation and prototype PCM-enhanced interior wallboards was built and tested in a natural exposure test (NET) facility in a hot-humid climate location. The test wall contained PCM wallboards and regular gypsum wallboard, for a side-by-side annual comparison study. Further, numerical modeling of the walls containing the nano-PCM wallboard was performed to determine its actual impact on wall-generated heating and cooling loads. The model was first validated using experimental data, and then used for annual simulations using Typical Meteorological Year (TMY3) weather data. This article presents the measured performance and numerical analysis evaluating the energy-saving potential of the nano-PCM-enhanced wallboard.
Experimental and numerical analysis of metal leaching from fly ash-amended highway bases
Cetin, Bora; Aydilek, Ahmet H.; Li, Lin
2012-05-15
Highlights: Black-Right-Pointing-Pointer This study is the evaluation of leaching potential of fly ash-lime mixed soils. Black-Right-Pointing-Pointer This objective is met with experimental and numerical analysis. Black-Right-Pointing-Pointer Zn leaching decreases with increase in fly ash content while Ba, B, Cu increases. Black-Right-Pointing-Pointer Decrease in lime content promoted leaching of Ba, B and Cu while Zn increases. Black-Right-Pointing-Pointer Numerical analysis predicted lower field metal concentrations. - Abstract: A study was conducted to evaluate the leaching potential of unpaved road materials (URM) mixed with lime activated high carbon fly ashes and to evaluate groundwater impacts of barium, boron, copper, and zinc leaching. This objective was met by a combination of batch water leach tests, column leach tests, and computer modeling. The laboratory tests were conducted on soil alone, fly ash alone, and URM-fly ash-lime kiln dust mixtures. The results indicated that an increase in fly ash and lime content has significant effects on leaching behavior of heavy metals from URM-fly ash mixture. An increase in fly ash content and a decrease in lime content promoted leaching of Ba, B and Cu whereas Zn leaching was primarily affected by the fly ash content. Numerically predicted field metal concentrations were significantly lower than the peak metal concentrations obtained in laboratory column leach tests, and field concentrations decreased with time and distance due to dispersion in soil vadose zone.
Godfrey, Brendan B.; Vay, Jean-Luc
2013-09-01
Rapidly growing numerical instabilities routinely occur in multidimensional particle-in-cell computer simulations of plasma-based particle accelerators, astrophysical phenomena, and relativistic charged particle beams. Reducing instability growth to acceptable levels has necessitated higher resolution grids, high-order field solvers, current filtering, etc. except for certain ratios of the time step to the axial cell size, for which numerical growth rates and saturation levels are reduced substantially. This paper derives and solves the cold beam dispersion relation for numerical instabilities in multidimensional, relativistic, electromagnetic particle-in-cell programs employing either the standard or the ColeKarkkainnen finite difference field solver on a staggered mesh and the common Esirkepov current-gathering algorithm. Good overall agreement is achieved with previously reported results of the WARP code. In particular, the existence of select time steps for which instabilities are minimized is explained. Additionally, an alternative field interpolation algorithm is proposed for which instabilities are almost completely eliminated for a particular time step in ultra-relativistic simulations.
Gao, Kai; Chung, Eric T.; Gibson, Richard L.; Fu, Shubin; Efendiev, Yalchin
2015-06-05
The development of reliable methods for upscaling fine scale models of elastic media has long been an important topic for rock physics and applied seismology. Several effective medium theories have been developed to provide elastic parameters for materials such as finely layered media or randomly oriented or aligned fractures. In such cases, the analytic solutions for upscaled properties can be used for accurate prediction of wave propagation. However, such theories cannot be applied directly to homogenize elastic media with more complex, arbitrary spatial heterogeneity. We therefore propose a numerical homogenization algorithm based on multiscale finite element methods for simulating elasticmore » wave propagation in heterogeneous, anisotropic elastic media. Specifically, our method used multiscale basis functions obtained from a local linear elasticity problem with appropriately defined boundary conditions. Homogenized, effective medium parameters were then computed using these basis functions, and the approach applied a numerical discretization that is similar to the rotated staggered-grid finite difference scheme. Comparisons of the results from our method and from conventional, analytical approaches for finely layered media showed that the homogenization reliably estimated elastic parameters for this simple geometry. Additional tests examined anisotropic models with arbitrary spatial heterogeneity where the average size of the heterogeneities ranged from several centimeters to several meters, and the ratio between the dominant wavelength and the average size of the arbitrary heterogeneities ranged from 10 to 100. Comparisons to finite-difference simulations proved that the numerical homogenization was equally accurate for these complex cases.« less
Gao, Kai; Chung, Eric T.; Gibson, Richard L.; Fu, Shubin; Efendiev, Yalchin
2015-06-05
The development of reliable methods for upscaling fine scale models of elastic media has long been an important topic for rock physics and applied seismology. Several effective medium theories have been developed to provide elastic parameters for materials such as finely layered media or randomly oriented or aligned fractures. In such cases, the analytic solutions for upscaled properties can be used for accurate prediction of wave propagation. However, such theories cannot be applied directly to homogenize elastic media with more complex, arbitrary spatial heterogeneity. We therefore propose a numerical homogenization algorithm based on multiscale finite element methods for simulating elastic wave propagation in heterogeneous, anisotropic elastic media. Specifically, our method used multiscale basis functions obtained from a local linear elasticity problem with appropriately defined boundary conditions. Homogenized, effective medium parameters were then computed using these basis functions, and the approach applied a numerical discretization that is similar to the rotated staggered-grid finite difference scheme. Comparisons of the results from our method and from conventional, analytical approaches for finely layered media showed that the homogenization reliably estimated elastic parameters for this simple geometry. Additional tests examined anisotropic models with arbitrary spatial heterogeneity where the average size of the heterogeneities ranged from several centimeters to several meters, and the ratio between the dominant wavelength and the average size of the arbitrary heterogeneities ranged from 10 to 100. Comparisons to finite-difference simulations proved that the numerical homogenization was equally accurate for these complex cases.
On a framework for generating PoD curves assisted by numerical simulations
Subair, S. Mohamed Agrawal, Shweta Balasubramaniam, Krishnan Rajagopal, Prabhu; Kumar, Anish; Rao, Purnachandra B.; Tamanna, Jayakumar
2015-03-31
The Probability of Detection (PoD) curve method has emerged as an important tool for the assessment of the performance of NDE techniques, a topic of particular interest to the nuclear industry where inspection qualification is very important. The conventional experimental means of generating PoD curves though, can be expensive, requiring large data sets (covering defects and test conditions), and equipment and operator time. Several methods of achieving faster estimates for PoD curves using physics-based modelling have been developed to address this problem. Numerical modelling techniques are also attractive, especially given the ever-increasing computational power available to scientists today. Here we develop procedures for obtaining PoD curves, assisted by numerical simulation and based on Bayesian statistics. Numerical simulations are performed using Finite Element analysis for factors that are assumed to be independent, random and normally distributed. PoD curves so generated are compared with experiments on austenitic stainless steel (SS) plates with artificially created notches. We examine issues affecting the PoD curve generation process including codes, standards, distribution of defect parameters and the choice of the noise threshold. We also study the assumption of normal distribution for signal response parameters and consider strategies for dealing with data that may be more complex or sparse to justify this. These topics are addressed and illustrated through the example case of generation of PoD curves for pulse-echo ultrasonic inspection of vertical surface-breaking cracks in SS plates.
A new dipolar potential for numerical simulations of polar fluids on the 4D hypersphere
Caillol, Jean-Michel; Trulsson, Martin
2014-09-28
We present a new method for Monte Carlo or Molecular Dynamics numerical simulations of three-dimensional polar fluids. The simulation cell is defined to be the surface of the northern hemisphere of a four-dimensional (hyper)sphere. The point dipoles are constrained to remain tangent to the sphere and their interactions are derived from the basic laws of electrostatics in this geometry. The dipole-dipole potential has two singularities which correspond to the following boundary conditions: when a dipole leaves the northern hemisphere at some point of the equator, it reappears at the antipodal point bearing the same dipole moment. We derive all the formal expressions needed to obtain the thermodynamic and structural properties of a polar liquid at thermal equilibrium in actual numerical simulation. We notably establish the expression of the static dielectric constant of the fluid as well as the behavior of the pair correlation at large distances. We report and discuss the results of extensive numerical Monte Carlo simulations for two reference states of a fluid of dipolar hard spheres and compare these results with previous methods with a special emphasis on finite size effects.
Numerical Simulations of Subscale Wind Turbine Rotor Inboard Airfoils at Low Reynolds Number
Blaylock, Myra L.; Maniaci, David Charles; Resor, Brian R.
2015-04-01
New blade designs are planned to support future research campaigns at the SWiFT facility in Lubbock, Texas. The sub-scale blades will reproduce specific aerodynamic characteristics of utility-scale rotors. Reynolds numbers for megawatt-, utility-scale rotors are generally above 2-8 million. The thickness of inboard airfoils for these large rotors are typically as high as 35-40%. The thickness and the proximity to three-dimensional flow of these airfoils present design and analysis challenges, even at the full scale. However, more than a decade of experience with the airfoils in numerical simulation, in the wind tunnel, and in the field has generated confidence in their performance. Reynolds number regimes for the sub-scale rotor are significantly lower for the inboard blade, ranging from 0.7 to 1 million. Performance of the thick airfoils in this regime is uncertain because of the lack of wind tunnel data and the inherent challenge associated with numerical simulations. This report documents efforts to determine the most capable analysis tools to support these simulations in an effort to improve understanding of the aerodynamic properties of thick airfoils in this Reynolds number regime. Numerical results from various codes of four airfoils are verified against previously published wind tunnel results where data at those Reynolds numbers are available. Results are then computed for other Reynolds numbers of interest.
Preliminary assessment of numerical data requirements TA-73 landfill Los Alamos, New Mexico
Not Available
1993-11-19
A numerical model, TOUGH2, was selected for describing liquid- and gas-phase flow in the unsaturated tuff underlying the TA-73 landfill. The model was selected primarily for its ability to simulate the significant mechanisms that may affect transport of contaminants through the vadose zone at the TA-73 landfill, including non-isothermal flow through fractured media. TOUGH2 is the best documented, verified, and validated model capable of performing the required simulations. The sensitivity analyses that were performed and describes in this report identified the input parameters that the selected numerical model is most sensitive to. The input parameters analyzed were saturated hydraulic conductivity, van Genuchten {alpha} and n, residual and saturated moisture contents, infiltration rate, fracture spacing and permeability, atmospheric pressure, and temperature. The sensitivity analyses were performed using a model grid that was designed to incorporate the regions in the landfill vicinity where contaminant transport is likely to occur and where the physical processes affecting flow and transport are the most dynamic. The sensitivity analyses performed suggest that the model is quite sensitive to a number of input parameters, including saturated hydraulic conductivity, the van Genuchten parameters {alpha} and n (for both the tuff matrix and fractures), fracture density and aperture, and atmospheric pressure. The results indicate that additional site-specific hydraulic properties and fracture data should be obtained before attempting to perform predictive, numerical simulations of gas- and liquid-phase flow beneath the landfill.
Numerical Modeling of the Lake Mary Road Bridge for Foundation Reuse Assessment
Sitek, M. A.; Bojanowski, C.; Lottes, S. A.
2015-04-01
This project uses numerical techniques to assess the structural integrity and capacity of the bridge foundations and, as a result, reduces the risk associated with reusing the same foundation for a new superstructure. Nondestructive test methods of different types were used in combination with the numerical modeling and analysis. The onsite tests included visual inspection, tomography, ground penetrating radar, drilling boreholes and coreholes, and the laboratory tests on recovered samples. The results were utilized to identify the current geometry of the structure with foundation, including the hidden geometry of the abutments and piers, and soil and foundation material properties. This data was used to build the numerical models and run computational analyses on a high performance computer cluster to assess the structural integrity of the bridge and foundations including the suitability of the foundation for reuse with a new superstructure and traffic that will increase the load on the foundations. Computational analysis is more cost-effective and gives an advantage of getting more detailed knowledge about the structural response. It also enables to go beyond non-destructive testing and find the failure conditions without destroying the structure under consideration.
Pedler, William H. (Radon Abatement Systems, Inc., Golden, CO); Jepsen, Richard Alan (Sandia National Laboratories, Carlsbad, NM)
2003-08-01
The requirement to accurately measure subsurface groundwater flow at contaminated sites, as part of a time and cost effective remediation program, has spawned a variety of flow evaluation technologies. Validation of the accuracy and knowledge regarding the limitations of these technologies are critical for data quality and application confidence. Leading the way in the effort to validate and better understand these methodologies, the US Army Environmental Center has funded a multi-year program to compare and evaluate all viable horizontal flow measurement technologies. This multi-year program has included a field comparison phase, an application of selected methods as part of an integrated site characterization program phase, and most recently, a laboratory and numerical simulator phase. As part of this most recent phase, numerical modeling predictions and laboratory measurements were made in a simulated fracture borehole set-up within a controlled flow simulator. The scanning colloidal borescope flowmeter (SCBFM) and advanced hydrophysical logging (NxHpL{trademark}) tool were used to measure velocities and flow rate in a simulated fractured borehole in the flow simulator. Particle tracking and mass flux measurements were observed and recorded under a range of flow conditions in the simulator. Numerical models were developed to aid in the design of the flow simulator and predict the flow conditions inside the borehole. Results demonstrated that the flow simulator allowed for predictable, easily controlled, and stable flow rates both inside and outside the well. The measurement tools agreed well with each other over a wide range of flow conditions. The model results demonstrate that the Scanning Colloidal Borescope did not interfere with the flow in the borehole in any of the tests. The model is capable of predicting flow conditions and agreed well with the measurements and observations in the flow simulator and borehole. Both laboratory and model results showed a
Gustavsen Ph.D., Arild; Goudey, Howdy; Kohler, Christian; Arasteh P.E., Dariush; Uvslokk, Sivert; Talev, Goce; Petter Jelle Ph.D., Bjorn
2010-06-17
While window frames typically represent 20-30percent of the overall window area, their impact on the total window heat transfer rates may be much larger. This effect is even greater in low-conductance (highly insulating) windows which incorporate very low conductance glazings. Developing low-conductance window frames requires accurate simulation tools for product research and development. The Passivhaus Institute in Germany states that windows (glazing and frames, combined) should have U-values not exceeding 0.80 W/(m??K). This has created a niche market for highly insulating frames, with frame U-values typically around 0.7-1.0 W/(m2 cdot K). The U-values reported are often based on numerical simulations according to international simulation standards. It is prudent to check the accuracy of these calculation standards, especially for high performance products before more manufacturers begin to use them to improve other product offerings. In this paper the thermal transmittance of five highly insulating window frames (three wooden frames, one aluminum frame and one PVC frame), found from numerical simulations and experiments, are compared. Hot box calorimeter results are compared with numerical simulations according to ISO 10077-2 and ISO 15099. In addition CFD simulations have been carried out, in order to use the most accurate tool available to investigate the convection and radiation effects inside the frame cavities. Our results show that available tools commonly used to evaluate window performance, based on ISO standards, give good overall agreement, but specific areas need improvement.
NUMERICAL SIMULATIONS OF CHROMOSPHERIC ANEMONE JETS ASSOCIATED WITH MOVING MAGNETIC FEATURES
Yang, Liping; He, Jiansen; Tu, Chuanyi; Zhang, Lei; Peter, Hardi; Feng, Xueshang; Zhang, Shaohua
2013-11-01
Observations with the space-based solar observatory Hinode show that small-scale magnetic structures in the photosphere are found to be associated with a particular class of jets of plasma in the chromosphere called anemone jets. The goal of our study is to conduct a numerical experiment of such chromospheric anemone jets related to the moving magnetic features (MMFs). We construct a 2.5 dimensional numerical MHD model to describe the process of magnetic reconnection between the MMFs and the pre-existing ambient magnetic field, which is driven by the horizontal motion of the magnetic structure in the photosphere. We include thermal conduction parallel to the magnetic field and optically thin radiative losses in the corona to account for a self-consistent description of the evaporation process during the heating of the plasma due to the reconnection process. The motion of the MMFs leads to the expected jet and our numerical results can reproduce many observed characteristics of chromospheric anemone jets, topologically and quantitatively. As a result of the tearing instability, plasmoids are generated in the reconnection process that are consistent with the observed bright moving blobs in the anemone jets. An increase in the thermal pressure at the base of the jet is also driven by the reconnection, which induces a train of slow-mode shocks propagating upward. These shocks are a secondary effect, and only modulate the outflow of the anemone jet. The jet itself is driven by the energy input due to the reconnection of the MMFs and the ambient magnetic field.
Anooshehpoor, Rasool; Purvance, Matthew D.; Brune, James N.; Preston, Leiph A.; Anderson, John G.; Smith, Kenneth D.
2006-09-29
This report covers the following projects: Shake table tests of precarious rock methodology, field tests of precarious rocks at Yucca Mountain and comparison of the results with PSHA predictions, study of the coherence of the wave field in the ESF, and a limited survey of precarious rocks south of the proposed repository footprint. A series of shake table experiments have been carried out at the University of Nevada, Reno Large Scale Structures Laboratory. The bulk of the experiments involved scaling acceleration time histories (uniaxial forcing) from 0.1g to the point where the objects on the shake table overturned a specified number of times. The results of these experiments have been compared with numerical overturning predictions. Numerical predictions for toppling of large objects with simple contact conditions (e.g., I-beams with sharp basal edges) agree well with shake-table results. The numerical model slightly underpredicts the overturning of small rectangular blocks. It overpredicts the overturning PGA for asymmetric granite boulders with complex basal contact conditions. In general the results confirm the approximate predictions of previous studies. Field testing of several rocks at Yucca Mountain has approximately confirmed the preliminary results from previous studies, suggesting that he PSHA predictions are too high, possibly because the uncertainty in the mean of the attenuation relations. Study of the coherence of wavefields in the ESF has provided results which will be very important in design of the canisters distribution, in particular a preliminary estimate of the wavelengths at which the wavefields become incoherent. No evidence was found for extreme focusing by lens-like inhomogeneities. A limited survey for precarious rocks confirmed that they extend south of the repository, and one of these has been field tested.
THE REBOUND CONDITION OF DUST AGGREGATES REVEALED BY NUMERICAL SIMULATION OF THEIR COLLISIONS
Wada, Koji; Tanaka, Hidekazu; Yamamoto, Tetsuo; Suyama, Toru; Kimura, Hiroshi
2011-08-10
Collisional growth of dust aggregates is a plausible root of planetesimals forming in protoplanetary disks. However, a rebound of colliding dust aggregates prevents dust from growing into planetesimals. In fact, rebounding aggregates are observed in laboratory experiments but not in previous numerical simulations. Therefore, the condition of rebound between dust aggregates should be clarified to better understand the processes of dust growth and planetesimal formation. We have carried out numerical simulations of aggregate collisions for various types of aggregates and succeeded in reproducing a rebound of colliding aggregates under specific conditions. Our finding is that in the rebound process, the key factor of the aggregate structure is the coordination number, namely, the number of particles in contact with a particle. A rebound is governed by the energy dissipation along with restructuring of the aggregates and a large coordination number inhibits the restructuring at collisions. Results of our numerical simulation for various aggregates indicate that they stick to each other when the mean coordination number is less than 6, regardless of their materials and structures, as long as their collision velocity is less than the critical velocity for fragmentation. This criterion of the coordination number would correspond to a filling factor of {approx}0.3, which is somewhat larger than that reported in laboratory experiments. In protoplanetary disks, dust aggregates are expected to have low bulk densities (<0.1 g cm{sup -3}) during their growth, which would prevent dust aggregates from rebounding. This result supports the formation of planetesimals with direct dust growth in protoplanetary disks.
Wimmer, Thomas Srimathveeravalli, Govindarajan; Gutta, Narendra; Ezell, Paula C.; Monette, Sebastien; Maybody, Majid; Erinjery, Joseph P.; Durack, Jeremy C.; Coleman, Jonathan A.; Solomon, Stephen B.
2015-02-15
PurposeNumerical simulations are used for treatment planning in clinical applications of irreversible electroporation (IRE) to determine ablation size and shape. To assess the reliability of simulations for treatment planning, we compared simulation results with empiric outcomes of renal IRE using computed tomography (CT) and histology in an animal model.MethodsThe ablation size and shape for six different IRE parameter sets (70–90 pulses, 2,000–2,700 V, 70–100 µs) for monopolar and bipolar electrodes was simulated using a numerical model. Employing these treatment parameters, 35 CT-guided IRE ablations were created in both kidneys of six pigs and followed up with CT immediately and after 24 h. Histopathology was analyzed from postablation day 1.ResultsAblation zones on CT measured 81 ± 18 % (day 0, p ≤ 0.05) and 115 ± 18 % (day 1, p ≤ 0.09) of the simulated size for monopolar electrodes, and 190 ± 33 % (day 0, p ≤ 0.001) and 234 ± 12 % (day 1, p ≤ 0.0001) for bipolar electrodes. Histopathology indicated smaller ablation zones than simulated (71 ± 41 %, p ≤ 0.047) and measured on CT (47 ± 16 %, p ≤ 0.005) with complete ablation of kidney parenchyma within the central zone and incomplete ablation in the periphery.ConclusionBoth numerical simulations for planning renal IRE and CT measurements may overestimate the size of ablation compared to histology, and ablation effects may be incomplete in the periphery.
Selection of a numerical unsaturated flow code for tilted capillary barrier performance evaluation
Webb, S.W. [Sandia National Labs., Albuquerque, NM (United States). Geohydrology Dept.
1996-09-01
Capillary barriers consisting of tilted fine-over-coarse layers have been suggested as landfill covers as a means to divert water infiltration away from sensitive underground regions under unsaturated flow conditions, especially for arid and semi-arid regions. Typically, the HELP code is used to evaluate landfill cover performance and design. Unfortunately, due to its simplified treatment of unsaturated flow and its essentially one-dimensional nature, HELP is not adequate to treat the complex multidimensional unsaturated flow processes occurring in a tilted capillary barrier. In order to develop the necessary mechanistic code for the performance evaluation of tilted capillary barriers, an efficient and comprehensive unsaturated flow code needs to be selected for further use and modification. The present study evaluates a number of candidate mechanistic unsaturated flow codes for application to tilted capillary barriers. Factors considered included unsaturated flow modeling, inclusion of evapotranspiration, nodalization flexibility, ease of modification, and numerical efficiency. A number of unsaturated flow codes are available for use with different features and assumptions. The codes chosen for this evaluation are TOUGH2, FEHM, and SWMS{_}2D. All three codes chosen for this evaluation successfully simulated the capillary barrier problem chosen for the code comparison, although FEHM used a reduced grid. The numerical results are a strong function of the numerical weighting scheme. For the same weighting scheme, similar results were obtained from the various codes. Based on the CPU time of the various codes and the code capabilities, the TOUGH2 code has been selected as the appropriate code for tilted capillary barrier performance evaluation, possibly in conjunction with the infiltration, runoff, and evapotranspiration models of HELP. 44 refs.
Analytical and Numerical Solutions of Generalized Fokker-Planck Equations - Final Report
Prinja, Anil K.
2000-12-31
The overall goal of this project was to develop advanced theoretical and numerical techniques to quantitatively describe the spreading of a collimated beam of charged particles in space, in angle, and in energy, as a result of small deflection, small energy transfer Coulomb collisions with the target nuclei and electrons. Such beams arise in several applications of great interest in nuclear engineering, and include electron and ion radiotherapy, ion beam modification of materials, accelerator transmutation of waste, and accelerator production of tritium, to name some important candidates. These applications present unique and difficult modeling challenges, but from the outset are amenable to the language of ''transport theory'', which is very familiar to nuclear engineers and considerably less-so to physicists and material scientists. Thus, our approach has been to adopt a fundamental description based on transport equations, but the forward peakedness associated with charged particle interactions precludes a direct application of solution methods developed for neutral particle transport. Unique problem formulations and solution techniques are necessary to describe the transport and interaction of charged particles. In particular, we have developed the Generalized Fokker-Planck (GFP) approach to describe the angular and radial spreading of a collimated beam and a renormalized transport model to describe the energy-loss straggling of an initially monoenergetic distribution. Both analytic and numerical solutions have been investigated and in particular novel finite element numerical methods have been developed. In the first phase of the project, asymptotic methods were used to develop closed form solutions to the GFP equation for different orders of expansion, and was described in a previous progress report. In this final report we present a detailed description of (i) a novel energy straggling model based on a Fokker-Planck approximation but which is adapted for a
Aksenova, A.E.; Chudanov, V.V.; Strizhov, V.F.; Vabishchevich, P.N.
1995-09-01
Unsteady natural convection of a heat-generating fluid with phase transitions in the enclosures of a square section with isothermal rigid walls is investigated numerically for a wide range of dimensionless parameters. The quasisteady state solutions of conjugate heat and mass transfer problem are compared with available experimental results. Correlation relations for heat flux distributions at the domain boundaries depending on Rayleigh and Ostrogradskii numbers are obtained. It is shown that generally heat transfer is governed both by natural circulation and crust formation phenomena. Results of this paper may be used for analysis of experiments with prototypic core materials.
All-reflective optical target illumination system with high numerical aperture
Thomas, Carlton E.; Sigler, Robert D.; Hoeger, John G.
1979-01-01
An all-reflective optical system for providing illumination of a target focal region at high numerical aperture from a pair of confluent collimated light beams. The collimated beams are each incident upon an associated concave eccentric pupil paraboloidal reflective surface, and thereby each focused through an opening in an associated outer ellipsoidal reflective surface onto a plane reflector. Each beam is reflected by its associated plane reflector onto the opposing concave surface of the outer ellipsoids to be focused through an opening in the plane surface onto an opposing inner concave ellipsoidal reflective surface, and thence onto the target region.
Contribution to the numerical study of turbulence in high intensity discharge lamps
Kaziz, S.; Ben Ahmed, R.; Helali, H.; Gazzah, H.; Charrada, K. [Unite d'Etude des Milieux Ionises et Reactifs, IPEIM, 5019 route de Kairouan Monastir (Tunisia)
2011-07-15
We present in this paper a comparison between results obtained with a laminar and turbulent models for high-pressure mercury arc. The two models are based on the resolution of bidimensional time-dependent equations by a semi-implicit finite-element code. The numerical computation of turbulent model is solved with large eddy simulation model; this approach takes into account the various scales of turbulence by a filtering method on each scale. The results show the quantitative influence of turbulence on the flow fields and also the difference between laminar and turbulent effects on the dynamic thermal behaviour and on the characteristics of the discharge.
Direct numerical simulations of fluid flow, heat transfer and phase changes
Juric, D.; Tryggvason, G.; Han, J.
1997-04-01
Direct numerical simulations of fluid flow, heat transfer, and phase changes are presented. The simulations are made possible by a recently developed finite difference/front tracking method based on the one-field formulation of the governing equations where a single set of conservation equations is written for all the phases involved. The conservation equations are solved on a fixed rectangular grid, but the phase boundaries are kept sharp by tracking them explicitly by a moving grid of lower dimension. The method is discussed and applications to boiling heat transfer and the solidification of drops colliding with a wall are shown.
Experimental Observations and Numerical Prediction of Induction Heating in a Graphite Test Article
Jankowski, Todd A [Los Alamos National Laboratory; Johnson, Debra P [Los Alamos National Laboratory; Jurney, James D [Los Alamos National Laboratory; Freer, Jerry E [Los Alamos National Laboratory; Dougherty, Lisa M [Los Alamos National Laboratory; Stout, Stephen A [Los Alamos National Laboratory
2009-01-01
The induction heating coils used in the plutonium casting furnaces at the Los Alamos National Laboratory are studied here. A cylindrical graphite test article has been built, instrumented with thermocouples, and heated in the induction coil that is normally used to preheat the molds during casting operations. Preliminary results of experiments aimed at understanding the induction heating process in the mold portion of the furnaces are reported. The experiments have been modeled in COMSOL Multiphysics and the numerical and experimental results are compared to one another. These comparisons provide insight into the heating process and provide a benchmark for COMSOL calculations of induction heating in the mold portion of the plutonium casting furnaces.
2D numerical simulation of the MEP energy-transport model with a finite difference scheme
Romano, V. . E-mail: romano@dmi.unict.it
2007-02-10
A finite difference scheme of Scharfetter-Gummel type is used to simulate a consistent energy-transport model for electron transport in semiconductors devices, free of any fitting parameters, formulated on the basis of the maximum entropy principle. Simulations of silicon n{sup +}-n-n{sup +} diodes, 2D-MESFET and 2D-MOSFET and comparisons with the results obtained by a direct simulation of the Boltzmann transport equation and with other energy-transport models, known in the literature, show the validity of the model and the robustness of the numerical scheme.
Liu, Lai; Qin, Guan-Shi Tian, Qi-jun; Zhao, Dan; Qin, Wei-Ping
2014-04-28
We numerically investigate Raman soliton generation in a fluoride photonic crystal fiber (PCF) pumped by 1.93 μm femtosecond fiber lasers in order to get widely tunable laser source in the mid-infrared region. The simulated results show that a continuously tunable range (1.93 ∼ 3.95 μm) over 2000 nm is achieved in 1-m-long fluoride PCF pumped by a 1.93 μm femtosecond fiber laser with a pulse width of 200 fs. The power conversion efficiency is also calculated and the maximum efficiency can be up to 84.27%.
Oliva, A.; Costa, M.; Perez Segarra, C.D. )
1991-01-01
A numerical model has been developed for determination of thermal behavior of solar collector. The model takes into account the multidimensional and transient aspects that characterize the phenomenon of heat transfer in a collector. The modelization carried out allows the analysis of the influence of such aspects as: flow nonuniformity distribution, areas of shadow, and variations in dimension and properties of the different elements. These aspects can be analyzed equally for steady and nonsteady outdoor conditions. Illustrative situations of the influence on the collector performance of the different aspects previously mentioned are shown.
Numerical simulation of alumina spraying in argon-helium plasma jet
Chang, C.H.
1992-01-01
A new numerical model is described for simulating thermal plasmas containing entrained particles, with emphasis on plasma spraying applications. The plasma is represented as a continuum multicomponent chemically reacting ideal gas, while the particles are tracked as discrete Lagrangian entities coupled to the plasma. Computational results are presented from a transient simulation of alumina spraying in a turbulent argon-helium plasma jet in air environment, including torch geometry, substrate, and multiple species with chemical reactions. Particle-plasma interactions including turbulent dispersion have been modeled in a fully self-consistent manner. Interactions between the plasma and the torch and substrate walls are modeled using wall functions. (15 refs.)
Numerical simulation of alumina spraying in argon-helium plasma jet
Chang, C.H.
1992-08-01
A new numerical model is described for simulating thermal plasmas containing entrained particles, with emphasis on plasma spraying applications. The plasma is represented as a continuum multicomponent chemically reacting ideal gas, while the particles are tracked as discrete Lagrangian entities coupled to the plasma. Computational results are presented from a transient simulation of alumina spraying in a turbulent argon-helium plasma jet in air environment, including torch geometry, substrate, and multiple species with chemical reactions. Particle-plasma interactions including turbulent dispersion have been modeled in a fully self-consistent manner. Interactions between the plasma and the torch and substrate walls are modeled using wall functions. (15 refs.)
Shen, J.; Shi, M.; Tanaka, T. Matsuyama, K.
2015-05-07
The spin transfer torque magnetization reversal of synthetic ferrimagnetic free layers under pulsed temperature rise was numerically studied by solving the LandauLifshitzGilbert equation, taking into account the stochastic random fields, the temperature dependence of magnetic parameters, and the spin torque terms. The anti-parallel magnetization configuration was retained at the elevated temperature, due to interlayer dipole coupling. A significant thermal assistance effect, resulting in a 40% reduction in the switching current, was demonstrated during a nanosecond pulsed temperature rise up to 77% of the Curie temperature.
Numerical studies of third-harmonic generation in laser filament in air perturbed by plasma spot
Feng Liubin; Lu Xin; Liu Xiaolong; Li Yutong; Chen Liming; Ma Jinglong; Dong Quanli; Wang Weimin; Xi Tingting; Sheng Zhengming; Zhang Jie; He Duanwei
2012-07-15
Third-harmonic emission from laser filament intercepted by plasma spot is studied by numerical simulations. Significant enhancement of the third-harmonic generation is obtained due to the disturbance of the additional plasma. The contribution of the pure plasma effect and the possible plasma-enhanced third-order susceptibility on the third-harmonic generation enhancement are compared. It is shown that the plasma induced cancellation of destructive interference [Y. Liu et al., Opt. Commun. 284, 4706 (2011)] of two-colored filament is the dominant mechanism of the enhancement of third-harmonic generation.
Numerical prediction of energy consumption in buildings with controlled interior temperature
Jarošová, P.; Št’astník, S.
2015-03-10
New European directives bring strong requirement to the energy consumption of building objects, supporting the renewable energy sources. Whereas in the case of family and similar houses this can lead up to absurd consequences, for building objects with controlled interior temperature the optimization of energy demand is really needed. The paper demonstrates the system approach to the modelling of thermal insulation and accumulation abilities of such objetcs, incorporating the significant influence of additional physical processes, as surface heat radiation and moisture-driven deterioration of insulation layers. An illustrative example shows the numerical prediction of energy consumption of a freezing plant in one Central European climatic year.
Pan Yi; Buonanno, Alessandra; Buchman, Luisa T.; Chu, Tony; Scheel, Mark A.; Kidder, Lawrence E.; Pfeiffer, Harald P.
2010-04-15
We present the first attempt at calibrating the effective-one-body (EOB) model to accurate numerical relativity simulations of spinning, nonprecessing black-hole binaries. Aligning the EOB and numerical waveforms at low frequency over a time interval of 1000M, we first estimate the phase and amplitude errors in the numerical waveforms and then minimize the difference between numerical and EOB waveforms by calibrating a handful of EOB-adjustable parameters. In the equal-mass, spin aligned case, we find that phase and fractional amplitude differences between the numerical and EOB (2,2) mode can be reduced to 0.01 radian and 1%, respectively, over the entire inspiral waveforms. In the equal-mass, spin antialigned case, these differences can be reduced to 0.13 radian and 1% during inspiral and plunge, and to 0.4 radian and 10% during merger and ringdown. The waveform agreement is within numerical errors in the spin aligned case while slightly over numerical errors in the spin antialigned case. Using Enhanced LIGO and Advanced LIGO noise curves, we find that the overlap between the EOB and the numerical (2,2) mode, maximized over the initial phase and time of arrival, is larger than 0.999 for binaries with total mass 30M{sub {center_dot}-}200M{sub {center_dot}}. In addition to the leading (2,2) mode, we compare four subleading modes. We find good amplitude and frequency agreements between the EOB and numerical modes for both spin configurations considered, except for the (3,2) mode in the spin antialigned case. We believe that the larger difference in the (3,2) mode is due to the lack of knowledge of post-Newtonian spin effects in the higher modes.
Bansal, Gaurav; Mascarenhas, Ajith; Chen, Jacqueline H.
2014-10-01
In our paper, two- and three-dimensional direct numerical simulations (DNS) of autoignition phenomena in stratified dimethyl-ether (DME)/air turbulent mixtures are performed. A reduced DME oxidation mechanism, which was obtained using rigorous mathematical reduction and stiffness removal procedure from a detailed DME mechanism with 55 species, is used in the present DNS. The reduced DME mechanism consists of 30 chemical species. This study investigates the fundamental aspects of turbulence-mixing-autoignition interaction occurring in homogeneous charge compression ignition (HCCI) engine environments. A homogeneous isotropic turbulence spectrum is used to initialize the velocity field in the domain. Moreover, the computational configuration corresponds to a constant volume combustion vessel with inert mass source terms added to the governing equations to mimic the pressure rise due to piston motion, as present in practical engines. DME autoignition is found to be a complex three-staged process; each stage corresponds to a distinct chemical kinetic pathway. The distinct role of turbulence and reaction in generating scalar gradients and hence promoting molecular transport processes are investigated. Then, by applying numerical diagnostic techniques, the different heat release modes present in the igniting mixture are identified. In particular, the contribution of homogeneous autoignition, spontaneous ignition front propagation, and premixed deflagration towards the total heat release are quantified.
Benchmark of numerical tools simulating beam propagation and secondary particles in ITER NBI
Sartori, E. Veltri, P.; Serianni, G.; Dlougach, E.; Hemsworth, R.; Singh, M.
2015-04-08
Injection of high energy beams of neutral particles is a method for plasma heating in fusion devices. The ITER injector, and its prototype MITICA (Megavolt ITER Injector and Concept Advancement), are large extrapolations from existing devices: therefore numerical modeling is needed to set thermo-mechanical requirements for all beam-facing components. As the power and charge deposition originates from several sources (primary beam, co-accelerated electrons, and secondary production by beam-gas, beam-surface, and electron-surface interaction), the beam propagation along the beam line is simulated by comprehensive 3D models. This paper presents a comparative study between two codes: BTR has been used for several years in the design of the ITER HNB/DNB components; SAMANTHA code was independently developed and includes additional phenomena, such as secondary particles generated by collision of beam particles with the background gas. The code comparison is valuable in the perspective of the upcoming experimental operations, in order to prepare a reliable numerical support to the interpretation of experimental measurements in the beam test facilities. The power density map calculated on the Electrostatic Residual Ion Dump (ERID) is the chosen benchmark, as it depends on the electric and magnetic fields as well as on the evolution of the beam species via interaction with the gas. Finally the paper shows additional results provided by SAMANTHA, like the secondary electrons produced by volume processes accelerated by the ERID fringe-field towards the Cryopumps.
A Numerical Model of the Temperature Field of the Cast and Solidified Ceramic Material
Kavicka, Frantisek; Sekanina, Bohumil; Stransky, Karel; Stetina, Josef [Brno University of Technology, Brno, Technicka 2 (Czech Republic); Dobrovska, Jana [Technical University of Ostrava, Ostrava, Tr. 17.listopadu 17 (Czech Republic)
2010-06-15
Corundo-baddeleyit material (CBM)--EUCOR--is a heat- and wear-resistant material even at extreme temperatures. This article introduces a numerical model of solidification and cooling of this material in a non-metallic mould. The model is capable of determining the total solidification time of the casting and also the place of the casting which solidifies last. Furthermore, it is possible to calculate the temperature gradient in any point and time, and also determine the local solidification time and the solidification interval of any point. The local solidification time is one of the input parameters for the cooperating model of chemical heterogeneity. This second model and its application on samples of EUCOR prove that the applied method of measurement of chemical heterogeneity provides detailed quantitative information on the material structure and makes it possible to analyse the solidification process. The analysis of this process entails statistical processing of the results of the measurements of the heterogeneity of the components of EUCOR and performs correlation of individual components during solidification. The crystallisation process seems to be very complicated, where the macro- and microscopic segregations differ significantly. The verification of both numerical models was conducted on a real cast 350x200x400 mm block.
Tao, Y.B.; He, Y.L.
2010-10-15
A unified two-dimensional numerical model was developed for the coupled heat transfer process in parabolic solar collector tube, which includes nature convection, forced convection, heat conduction and fluid-solid conjugate problem. The effects of Rayleigh number (Ra), tube diameter ratio and thermal conductivity of the tube wall on the heat transfer and fluid flow performance were numerically analyzed. The distributions of flow field, temperature field, local Nu and local temperature gradient were examined. The results show that when Ra is larger than 10{sup 5}, the effects of nature convection must be taken into account. With the increase of tube diameter ratio, the Nusselt number in inner tube (Nu{sub 1}) increases and the Nusselt number in annuli space (Nu{sub 2}) decreases. With the increase of tube wall thermal conductivity, Nu{sub 1} decreases and Nu{sub 2} increases. When thermal conductivity is larger than 200 W/(m K), it would have little effects on Nu and average temperatures. Due to the effect of the nature convection, along the circumferential direction (from top to down), the temperature in the cross-section decreases and the temperature gradient on inner tube surface increases at first. Then, the temperature and temperature gradients would present a converse variation at {theta} near {pi}. The local Nu on inner tube outer surface increases along circumferential direction until it reaches a maximum value then it decreases again. (author)
Numerical modeling of the action of an explosion on an iron slab
Sugak, S.G.; Fortov, V.E.; Kanel', G.I.; Ni, A.L.; Stel'makh, V.G.
1983-09-01
This article examines the explosion of a condensed high explosive (HE) by a flat Armco iron slab. The fundamental physical processes accompanying the nonstationary two-dimensional compression pulse propagation in a metal are analyzed, a mathematical model of the process is formulated, and its numerical characteristics are determined. A cylindrical charge of trinitrotoluene of 20 mm diameter and height, initiated at the axial point on the free surface, was mounted on a 10-mm-thick and 120-mm-diameter armco iron disk. A finite-difference method using a quadrangular computational mesh is employed. It is assumed that the process of detonation transformation occurs instantaneously and is characterized only by singularities in the equation of state. Numerical modeling of the loading of an iron slab by an explosion showed that the simple kinetic relationship proposed for the fracture computation will assure a realistic description of the fracture process. It is determined that the progress of a reversible polymorphic transformation in the specimen material substantially influences the nature of its fracture by explosion. The magnitude of the strain on the strength properties of the material must be taken into account in order to achieve a detailed description of the fracture.
Austin, Ryan A.; Barton, Nathan R.; Reaugh, John E.; Fried, Laurence E.
2015-05-14
A numerical model is developed to study the shock wave ignition of HMX crystal. The model accounts for the coupling between crystal thermal/mechanical responses and chemical reactions that are driven by the temperature field. This allows for the direct numerical simulation of decomposition reactions in the hot spots formed by shock/impact loading. The model is used to simulate intragranular pore collapse under shock wave loading. In a reference case: (i) shear-enabled micro-jetting is responsible for a modest extent of reaction in the pore collapse region, and (ii) shear banding is found to be an important mode of localization. The shearmore » bands, which are filled with molten HMX, grow out of the pore collapse region and serve as potential ignition sites. The model predictions of shear banding and reactivity are found to be quite sensitive to the respective flow strengths of the solid and liquid phases. In this regard, it is shown that reasonable assumptions of liquid-HMX viscosity can lead to chemical reactions within the shear bands on a nanosecond time scale.« less
Cheng, C. L.; Gragg, M. J.; Perfect, E.; White, Mark D.; Lemiszki, P. J.; McKay, L. D.
2013-08-24
Numerical simulations are widely used in feasibility studies for geologic carbon sequestration. Accurate estimates of petrophysical parameters are needed as inputs for these simulations. However, relatively few experimental values are available for CO2-brine systems. Hence, a sensitivity analysis was performed using the STOMP numerical code for supercritical CO2 injected into a model confined deep saline aquifer. The intrinsic permeability, porosity, pore compressibility, and capillary pressure-saturation/relative permeability parameters (residual liquid saturation, residual gas saturation, and van Genuchten alpha and m values) were varied independently. Their influence on CO2 injection rates and costs were determined and the parameters were ranked based on normalized coefficients of variation. The simulations resulted in differences of up to tens of millions of dollars over the life of the project (i.e., the time taken to inject 10.8 million metric tons of CO2). The two most influential parameters were the intrinsic permeability and the van Genuchten m value. Two other parameters, the residual gas saturation and the residual liquid saturation, ranked above the porosity. These results highlight the need for accurate estimates of capillary pressure-saturation/relative permeability parameters for geologic carbon sequestration simulations in addition to measurements of porosity and intrinsic permeability.
Monitoring and Numerical Modeling of Shallow CO{sub 2} Injection, Greene County, Missouri
Rovey, Charles; Gouzie, Douglas; Biagioni, Richard
2013-09-30
The project titled Monitoring and Numerical Modeling of Shallow CO{sub 2} Injection, Greene County, Missouri provided training for three graduate students in areas related to carbon capture and storage. Numerical modeling of CO{sub 2} injection into the St. Francois aquifer at the Southwest Power Plant Site in Greene County, Missouri indicates that up to 4.1 x 10{sup 5} metric tons of CO{sub 2} per year could be injected for 30 years without exceeding a 3 MPa differential injection pressure. The injected CO{sub 2} would remain sequestered below the top of the overlying caprock (St. Francois confining unit) for more than 1000 years. Geochemical modeling indicates that portions of the injected CO{sub 2} will react rapidly with trace minerals in the aquifer to form various solid carbonate mineral phases. These minerals would store significant portions of injected CO{sub 2} over geologic time scales. Finally, a GIS data base on the pore-fluid chemistry of the overlying aquifer system in Missouri, the Ozark aquifer, was compiled from many sources. This data base could become useful in monitoring for leakage from future CO{sub 2} sequestration sites.
Numerical investigation of the double-arcing phenomenon in a cutting arc torch
Mancinelli, B. R.; Minotti, F. O.; Kelly, H.; Prevosto, L.
2014-07-14
A numerical investigation of the double-arcing phenomenon in a cutting arc torch is reported. The dynamics of the double-arcing were simulated by using a two-dimensional model of the gas breakdown development in the space-charge layer contiguous to the nozzle of a cutting arc torch operated with oxygen. The kinetic scheme includes ionization of heavy particles by electron impact, electron attachment, electron detachment, electronion recombination, and ionion recombination. Complementary measurements during double-arcing phenomena were also conducted. A marked rise of the nozzle voltage was found. The numerical results showed that the dynamics of a cathode spot at the exit of the nozzle inner surface play a key role in the raising of the nozzle voltage, which in turn allows more electrons to return to the wall at the nozzle inlet. The return flow of electrons thus closes the current loop of the double-arcing. The increase in the (floating) nozzle voltage is due to the fact that the increased electron emission at the spot is mainly compensated by the displacement current (the ions do not play a relevant role due to its low-mobility) until that the stationary state is achieved and the electron return flow fully-compensates the electron emission at the spot. A fairly good agreement was found between the model and the experiment for a spot emission current growth rate of the order of 7??10{sup 4}?A/s.
Dynamic Response of a Pulse-Heated, Thick-Walled, Hollow Sphere: Validation of Code Numerics
Canaan, R.E.
2000-01-19
Volumetric pulse heating of a thick-walled hollow sphere is numerically investigated. The primary objective is to validate a variety of LLNL 30 hydrocodes for modeling the dynamic behavior of fissile/fissionable metals subject to rapid ''fission-heating'' transients. The 30 codes tested include both DYNA3D and NIKE3D, as well as the ''ASCI'' code, ALE3D. The codes are compared ''head-to-head'' and are benchmarked against a 1D finite difference solution to the problem that is derived from basic principles. Three pulse-heating transients are examined with full-width-half-maximum pulse durations of 41{micro}s, 85{micro}s, and 140{micro}s, respectively. These three transients produce a significant range of dynamic responses in the thermo-elastic regime. We present results for dynamic radial displacements and stresses for each pulse, and also discuss which code features/options worked best for these types of calculations. In general, the code results are in excellent agreement for the simple system considered. Validation of code numerics in simple systems is a key first step toward future application of the codes in more complicated geometries (U).
Numerical integration of structural elements in NIKE3D and DYNA3D
Maker, B.N.; Whirley, R.G.; Engelmann, B.E.
1992-08-05
The beam and shell elements found in many linear elastic finite element codes accept integrated cross sectional properties as input, and produce solutions using classical beam and shell theory. These theories are built upon the equation of resultant forces and moments with integrals of assumed stress distributions over the cross section. In contrast, the structural elements in NIKE3D and DYNA3D are formulated to represent nonlinear geometric and material behavior. Thus stress distributions may not necessarily be representable by simple functions of cross section variables. In NIKE3D and DYNA3D, the Hughes-Liu beam element and all shell elements accommodate these more general stress distributions by computing stresses at various points in the cross section. The integration of stresses within each element is then performed numerically, using a variety of methods. This report describes these numerical integration procedures in detail, and highlights their application to engineering problems. Several other features of the structural elements are also described, including force and moment resultants, user-defined reference surfaces, and user-defined integration rules. Finally, the shear correction factor is described in a section which relates results from NIKE3D and DYNA3D to those obtained from classical beam theory.
Numerical study on microwave-sustained argon discharge under atmospheric pressure
Yang, Y.; Hua, W. Guo, S. Y.
2014-04-15
A numerical study on microwave sustained argon discharge under atmospheric pressure is reported in this paper. The purpose of this study is to investigate both the process and effects of the conditions of microwave-excited gas discharge under atmospheric pressure, thereby aiding improvements in the design of the discharge system, setting the appropriate working time, and controlling the operating conditions. A 3D model is presented, which includes the physical processes of electromagnetic wave propagation, electron transport, heavy species transport, gas flow, and heat transfer. The results can be obtained by means of the fluid approximation. The maxima of the electron density and gas temperature are 4.96 × 10{sup 18} m{sup −3} and 2514.8 K, respectively, and the gas pressure remains almost unchanged for typical operating conditions with a gas flow rate of 20 l/min, microwave power of 1000 W, and initial temperature of 473 K. In addition, the conditions (microwave power, gas flow rate, and initial temperature) of discharge are varied to obtain deeper information about the electron density and gas temperature. The results of our numerical study are valid and clearly describe both the physical process and effects of the conditions of microwave-excited argon discharge.
Ban-Weiss, G A; Chen, J Y; Buchholz, B A; Dibble, R W
2007-01-30
Biodiesel is a notable alternative to petroleum derived diesel fuel because it comes from natural domestic sources and thus reduces dependence on diminishing petroleum fuel from foreign sources, it likely lowers lifecycle greenhouse gas emissions, and it lowers an engine's emission of most pollutants as compared to petroleum derived diesel. However, the use of biodiesel often slightly increases a diesel engine's emission of smog forming nitrogen oxides (NO{sub x}) relative to petroleum diesel. In this paper, previously proposed theories for this slight NOx increase are reviewed, including theories based on biodiesel's cetane number, which leads to differing amounts of charge preheating, and theories based on the fuel's bulk modulus, which affects injection timing. This paper proposes an additional theory for the slight NO{sub x} increase of biodiesel. Biodiesel typically contains more double bonded molecules than petroleum derived diesel. These double bonded molecules have a slightly higher adiabatic flame temperature, which leads to the increase in NOx production for biodiesel. Our theory was verified using numerical simulations to show a NOx increase, due to the double bonded molecules, that is consistent with observation. Further, the details of these numerical simulations show that NOx is predominantly due to the Zeldovich mechanism.
Van Eerten, Hendrik J.; MacFadyen, Andrew I.
2012-06-01
We discuss jet dynamics for narrow and wide gamma-ray burst (GRB) afterglow jets and the observational implications of numerical simulations of relativistic jets in two dimensions. We confirm earlier numerical results that sideways expansion of relativistic jets during the bulk of the afterglow emission phase is logarithmic in time and find that this also applies to narrow jets with half opening angle of 0.05 rad. As a result, afterglow jets remain highly nonspherical until after they have become nonrelativistic. Although sideways expansion steepens the afterglow light curve after the jet break, the jet edges becoming visible dominates the jet break, which means that the jet break is sensitive to the observer angle even for narrow jets. Failure to take the observer angle into account can lead to an overestimation of the jet energy by up to a factor of four. This weakens the challenge posed to the magneter energy limit by extreme events such as GRB090926A. Late-time radio calorimetry based on a spherical nonrelativistic outflow model remains relevant when the observer is approximately on-axis and where differences of a few in flux level between the model and the simulation are acceptable. However, this does not imply sphericity of the outflow and therefore does not translate to high observer angles relevant to orphan afterglows. For more accurate calorimetry and in order to model significant late-time features such as the rise of the counterjet, detailed jet simulations remain indispensable.
Bansal, Gaurav; Mascarenhas, Ajith; Chen, Jacqueline H.
2014-10-01
In our paper, two- and three-dimensional direct numerical simulations (DNS) of autoignition phenomena in stratified dimethyl-ether (DME)/air turbulent mixtures are performed. A reduced DME oxidation mechanism, which was obtained using rigorous mathematical reduction and stiffness removal procedure from a detailed DME mechanism with 55 species, is used in the present DNS. The reduced DME mechanism consists of 30 chemical species. This study investigates the fundamental aspects of turbulence-mixing-autoignition interaction occurring in homogeneous charge compression ignition (HCCI) engine environments. A homogeneous isotropic turbulence spectrum is used to initialize the velocity field in the domain. Moreover, the computational configuration corresponds to amore » constant volume combustion vessel with inert mass source terms added to the governing equations to mimic the pressure rise due to piston motion, as present in practical engines. DME autoignition is found to be a complex three-staged process; each stage corresponds to a distinct chemical kinetic pathway. The distinct role of turbulence and reaction in generating scalar gradients and hence promoting molecular transport processes are investigated. Then, by applying numerical diagnostic techniques, the different heat release modes present in the igniting mixture are identified. In particular, the contribution of homogeneous autoignition, spontaneous ignition front propagation, and premixed deflagration towards the total heat release are quantified.« less
Rutqvist, Jonny; Rutqvist, J.; Moridis, G.J.
2008-06-01
In this paper, we describe the development and application of a numerical simulator that analyzes the geomechanical performance of hydrate-bearing sediments, which may become an important future energy supply. The simulator is developed by coupling a robust numerical simulator of coupled fluid flow, hydrate thermodynamics, and phase behavior in geologic media (TOUGH+HYDRATE) with an established geomechanical code (FLAC3D). We demonstrate the current simulator capabilities and applicability for two examples of geomechanical responses of hydrate bearing sediments during production-induced hydrate dissociation. In these applications, the coupled geomechanical behavior within hydrate-bearing seducements are considered through a Mohr-Coulomb constitutive model, corrected for changes in pore-filling hydrate and ice content, based on laboratory data. The results demonstrate how depressurization-based gas production from oceanic hydrate deposits may lead to severe geomechanical problems unless care is taken in designing the production scheme. We conclude that the coupled simulator can be used to design production strategies for optimizing production, while avoiding damaging geomechanical problems.
Numerical construction and flow simulation in networks of fractures using fractals
Yortsos, Y.C.; Acuna, J.A.
1991-11-01
Present models for the representation of naturally fractured systems rely on the double-porosity Warren-Root model or on random arrays of fractures. However, field observation in outcrops has demonstrated the existence of multiple length scales in many naturally fractured media. The existing models fail to capture this important fractal property. In this paper, we use concepts from the theory of fragmentation and from fractal geometry for the numerical construction of networks of fractures that have fractal characteristics. The method is based mainly on the work of Barnsley (1) and allows for great flexibility in the development of patterns. Numerical techniques are developed for the simulation of unsteady single phase flow in such networks. It is found that the pressure transient response of finite fractals behaves according to the analytical predictions of Chang and Yortsos (6), provided that there exists a power law in the mass-radius relationship around the test well location. Otherwise, the finite size effects become significant and interfere severely with the identification of the underlying fractal structure. 21 refs., 13 figs.
SEQUESTRATION OF METALS IN ACTIVE CAP MATERIALS: A LABORATORY AND NUMERICAL EVALUATION
Dixon, K.; Knox, A.
2012-02-13
Active capping involves the use of capping materials that react with sediment contaminants to reduce their toxicity or bioavailability. Although several amendments have been proposed for use in active capping systems, little is known about their long-term ability to sequester metals. Recent research has shown that the active amendment apatite has potential application for metals contaminated sediments. The focus of this study was to evaluate the effectiveness of apatite in the sequestration of metal contaminants through the use of short-term laboratory column studies in conjunction with predictive, numerical modeling. A breakthrough column study was conducted using North Carolina apatite as the active amendment. Under saturated conditions, a spike solution containing elemental As, Cd, Co, Se, Pb, Zn, and a non-reactive tracer was injected into the column. A sand column was tested under similar conditions as a control. Effluent water samples were periodically collected from each column for chemical analysis. Relative to the non-reactive tracer, the breakthrough of each metal was substantially delayed by the apatite. Furthermore, breakthrough of each metal was substantially delayed by the apatite compared to the sand column. Finally, a simple 1-D, numerical model was created to qualitatively predict the long-term performance of apatite based on the findings from the column study. The results of the modeling showed that apatite could delay the breakthrough of some metals for hundreds of years under typical groundwater flow velocities.
Austin, Ryan A.; Barton, Nathan R.; Reaugh, John E.; Fried, Laurence E.
2015-05-14
A numerical model is developed to study the shock wave ignition of HMX crystal. The model accounts for the coupling between crystal thermal/mechanical responses and chemical reactions that are driven by the temperature field. This allows for the direct numerical simulation of decomposition reactions in the hot spots formed by shock/impact loading. The model is used to simulate intragranular pore collapse under shock wave loading. In a reference case: (i) shear-enabled micro-jetting is responsible for a modest extent of reaction in the pore collapse region, and (ii) shear banding is found to be an important mode of localization. The shear bands, which are filled with molten HMX, grow out of the pore collapse region and serve as potential ignition sites. The model predictions of shear banding and reactivity are found to be quite sensitive to the respective flow strengths of the solid and liquid phases. In this regard, it is shown that reasonable assumptions of liquid-HMX viscosity can lead to chemical reactions within the shear bands on a nanosecond time scale.
An Implicit Algorithm for the Numerical Simulation of Shape-Memory Alloys
Becker, R; Stolken, J; Jannetti, C; Bassani, J
2003-10-16
Shape-memory alloys (SMA) have the potential to be used in a variety of interesting applications due to their unique properties of pseudoelasticity and the shape-memory effect. However, in order to design SMA devices efficiently, a physics-based constitutive model is required to accurately simulate the behavior of shape-memory alloys. The scope of this work is to extend the numerical capabilities of the SMA constitutive model developed by Jannetti et. al. (2003), to handle large-scale polycrystalline simulations. The constitutive model is implemented within the finite-element software ABAQUS/Standard using a user defined material subroutine, or UMAT. To improve the efficiency of the numerical simulations, so that polycrystalline specimens of shape-memory alloys can be modeled, a fully implicit algorithm has been implemented to integrate the constitutive equations. Using an implicit integration scheme increases the efficiency of the UMAT over the previously implemented explicit integration method by a factor of more than 100 for single crystal simulations.
Numerical studies of electron cyclotron wave current drive on HL-2A tokamak
Li, J. C.; Gong, X. Y.; Dong, J. Q.; Song, S. D.; Gao, Q. D.; Zheng, P. W.; Du, D.
2015-06-15
The electron cyclotron wave (ECW) current drive (CD) for the HL-2A tokamak is investigated numerically with a new ray-tracing and Fokker-Planck code. The code is benchmarked with other well-tested linear and quasilinear codes and is then used to study the electron cyclotron current drive on the HL-2A tokamak. The wave propagation, power deposition, and driven-current profiles are presented. The effect of electron trapping is also assessed. It is found that quasilinear effects are negligible at the present ECW power levels and that when both waves are injected at an angle of 20° on the plasma equatorial plane, the CD efficiency for the HL-2A saturates at ∼0.029 × 10{sup 20 }A/W/m{sup 2} and ∼0.020 × 10{sup 20 }A/W/m{sup 2} for the 0.5 MW/68 GHz first harmonic ordinary (O1) and 1 MW/140 GHz second harmonic extraordinary (X2) modes, respectively. The effects of the plasma density, temperature, and wave-launching position on the driven current are also investigated analytically and numerically.
Improving the quality of numerical software through user-centered design
Pancake, C. M., Oregon State University
1998-06-01
The software interface - whether graphical, command-oriented, menu-driven, or in the form of subroutine calls - shapes the user`s perception of what software can do. It also establishes upper bounds on software usability. Numerical software interfaces typically are based on the designer`s understanding of how the software should be used. That is a poor foundation for usability, since the features that are ``instinctively right`` from the developer`s perspective are often the very ones that technical programmers find most objectionable or most difficult to learn. This paper discusses how numerical software interfaces can be improved by involving users more actively in design, a process known as user-centered design (UCD). While UCD requires extra organization and effort, it results in much higher levels of usability and can actually reduce software costs. This is true not just for graphical user interfaces, but for all software interfaces. Examples show how UCD improved the usability of a subroutine library, a command language, and an invocation interface.
Terascale direct numerical simulations of turbulent combustion using S3D
Chen, Jackie; Klasky, Scott A; Hawkes, Evatt R; Sankaran, Ramanan; Choudhary, Alok; Yoo, Chun S; Liao, Wei-keng; Podhorszki, Norbert
2009-01-01
Computational science is paramount to the understanding of underlying processes in internal combustion engines of the future that will utilize non-petroleum-based alternative fuels, including carbon-neutral biofuels, and burn in new combustion regimes that will attain high efficiency while minimizing emissions of particulates and nitrogen oxides. Next-generation engines will likely operate at higher pressures, with greater amounts of dilution and utilize alternative fuels that exhibit a wide range of chemical and physical properties. Therefore, there is a significant role for high-fidelity simulations, direct numerical simulations (DNS), specifically designed to capture key turbulence-chemistry interactions in these relatively uncharted combustion regimes, and in particular, that can discriminate the effects of differences in fuel properties. In DNS, all of the relevant turbulence and flame scales are resolved numerically using high-order accurate numerical algorithms. As a consequence terascale DNS are computationally intensive, require massive amounts of computing power and generate tens of terabytes of data. Recent results from terascale DNS of turbulent flames are presented here, illustrating its role in elucidating flame stabilization mechanisms in a lifted turbulent hydrogen/air jet flame in a hot air coflow, and the flame structure of a fuel-lean turbulent premixed jet flame. Computing at this scale requires close collaborations between computer and combustion scientists to provide optimized scaleable algorithms and software for terascale simulations, efficient collective parallel I/O, tools for volume visualization of multiscale, multivariate data and automating the combustion workflow. The enabling computer science, applied to combustion science, is also required in many other terascale physics and engineering simulations. In particular, performance monitoring is used to identify the performance of key kernels in the DNS code, S3D and especially memory
Pan, Dongqing; Ma, Lulu; Xie, Yuanyuan; Yuan, Chris; Jen, Tien Chien
2015-03-15
Alumina thin film is typically studied as a model atomic layer deposition (ALD) process due to its high dielectric constant, high thermal stability, and good adhesion on various wafer surfaces. Despite extensive applications of alumina ALD in microelectronics industries, details on the physical and chemical processes are not yet well understood. ALD experiments are not able to shed adequate light on the detailed information regarding the transient ALD process. Most of current numerical approaches lack detailed surface reaction mechanisms, and their results are not well correlated with experimental observations. In this paper, the authors present a combined experimental and numerical study on the details of flow and surface reactions in alumina ALD using trimethylaluminum and water as precursors. Results obtained from experiments and simulations are compared and correlated. By experiments, growth rate on five samples under different deposition conditions is characterized. The deposition rate from numerical simulation agrees well with the experimental results. Details of precursor distributions in a full cycle of ALD are studied numerically to bridge between experimental observations and simulations. The 3D transient numerical model adopts surface reaction kinetics and mechanisms based on atomic-level studies to investigate the surface deposition process. Surface deposition is shown as a strictly self-limited process in our numerical studies. ALD is a complex strong-coupled fluid, thermal and chemical process, which is not only heavily dependent on the chemical kinetics and surface conditions but also on the flow and material distributions.
Ostermann, Lars; Seidel, Christian
2015-03-10
The numerical analysis of hydro power stations is an important method of the hydraulic design and is used for the development and optimisation of hydro power stations in addition to the experiments with the physical submodel of a full model in the hydraulic laboratory. For the numerical analysis, 2D and 3D models are appropriate and commonly used.The 2D models refer mainly to the shallow water equations (SWE), since for this flow model a large experience on a wide field of applications for the flow analysis of numerous problems in hydraulic engineering already exists. Often, the flow model is verified by in situ measurements. In order to consider 3D flow phenomena close to singularities like weirs, hydro power stations etc. the development of a hybrid fluid model is advantageous to improve the quality and significance of the global model. Here, an extended hybrid flow model based on the principle of the SWE is presented. The hybrid flow model directly links the numerical model with the experimental data, which may originate from physical full models, physical submodels and in-situ measurements. Hence a wide field of application of the hybrid model emerges including the improvement of numerical models and the strong coupling of numerical and experimental analysis.
Spherically symmetric cosmological spacetimes with dust and radiation — numerical implementation
Lim, Woei Chet; Regis, Marco; Clarkson, Chris E-mail: regis@to.infn.it
2013-10-01
We present new numerical cosmological solutions of the Einstein Field Equations. The spacetime is spherically symmetric with a source of dust and radiation approximated as a perfect fluid. The dust and radiation are necessarily non-comoving due to the inhomogeneity of the spacetime. Such a model can be used to investigate non-linear general relativistic effects present during decoupling or big-bang nucleosynthesis, as well as for investigating void models of dark energy with isocurvature degrees of freedom. We describe the full evolution of the spacetime as well as the redshift and luminosity distance for a central observer. After demonstrating accuracy of the code, we consider a few example models, and demonstrate the sensitivity of the late time model to the degree of inhomogeneity of the initial radiation contrast.
Analytical and numerical solution of one- and two-dimensional steady heat transfer in a coldplate
Jones, G.F.; Bennett, G.A.; Bultman, D.H.
1987-01-01
We develop analytical models for steady-state, one- and two-dimensional heat transfer in a single-material, flat-plate coldplate. Discrete heat sources are mounted on one side of the plate and heat transfer to a flowing fluid occurs on the other. The models are validated numerically using finite differences. We propose a simple procedure for estimating maximum coldplate temperature at the location of each heat source which includes thermal interaction among the sources. Results from one model are compared with data obtained for a composite coldplate operated in the laboratory. We demonstrate the utility of the models as diagnostic tools to be used for predicting the existence and extent of void volumes and delaminations in the composite material that can occur with coldplates of this type. Based on our findings, recommendations for effective coldplate design are given.
Numerical study on the influence of electron cyclotron current drive on tearing mode
Chen, Long; Liu, Jinyuan; Mao, Aohua; Sun, Jizhong, E-mail: jsun@dlut.edu.cn [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Duan, Ping [Department of Physics, Dalian Maritime University, Dalian 116026 (China)
2014-10-15
Controlling tearing modes by localized current drive is explored by using numerical simulation with a set of compressible magnetohydrodynamics equations. By examining the effects of different characteristics of driven current, such as density distribution, duration time, and deposition location, it is found that a driven current with larger magnitude and more focused deposition region shows a better suppression effect on the tearing modes. Meanwhile destabilizing effects are also observed when a driven current over a certain magnitude is applied continuously. In comparison with those on the X-point of the magnetic island, the results are better when the current deposition is targeted on the O-point. In addition, the timing control of the current deposition will be also addressed.
Defect reaction network in Si-doped InP : numerical predictions.
Schultz, Peter Andrew
2013-10-01
This Report characterizes the defects in the defect reaction network in silicon-doped, n-type InP deduced from first principles density functional theory. The reaction network is deduced by following exothermic defect reactions starting with the initially mobile interstitial defects reacting with common displacement damage defects in Si-doped InP until culminating in immobile reaction products. The defect reactions and reaction energies are tabulated, along with the properties of all the silicon-related defects in the reaction network. This Report serves to extend the results for intrinsic defects in SAND 2012-3313: %E2%80%9CSimple intrinsic defects in InP: Numerical predictions%E2%80%9D to include Si-containing simple defects likely to be present in a radiation-induced defect reaction sequence.
Full-Scale Numerical Modeling of Turbulent Processes in the Earth's Ionosphere
Eliasson, B.; Stenflo, L.; Shukla, P. K.
2008-10-15
We present a full-scale simulation study of ionospheric turbulence by means of a generalized Zakharov model based on the separation of variables into high-frequency and slow time scales. The model includes realistic length scales of the ionospheric profile and of the electromagnetic and electrostatic fields, and uses ionospheric plasma parameters relevant for high-latitude radio facilities such as Eiscat and HAARP. A nested grid numerical method has been developed to resolve the different length-scales, while avoiding severe restrictions on the time step. The simulation demonstrates the parametric decay of the ordinary mode into Langmuir and ion-acoustic waves, followed by a Langmuir wave collapse and short-scale caviton formation, as observed in ionospheric heating experiments.
Numerical prediction of the thermodynamic properties of ternary Al-Ni-Hf alloys
Romanowska, Jolanta; Kotowski, S?awomir; Zagula-Yavorska, Maryana
2014-10-06
Thermodynamic properties of ternary Al-Hf-Ni system, such as {sup ex}G, ?{sub Al}, ?{sub Ni} and ?{sub Zr} at 1373K were predicted on the basis of thermodynamic properties of binary systems included in the investigated ternary system. The idea of predicting {sup ex}G values was regarded as the calculation of excess Gibbs energy values inside a certain area (a Gibbs triangle) unless all boundary conditions, that is values of {sup ex}G on all legs of the triangle are known. {sup ex}G and L{sub ijk} ternary interaction parameters in the Muggianu extension of the Redlich-Kister formalism are calculated numerically using Wolfram Mathematica 9 software.
Three dimensional numerical simulations of the UPS-292 stratified charge engine
O'Rourke, P.J.; Amsden, A.A.
1987-01-01
The authors present and analyze three-dimensional calculations of the spray, mixing and combustion in the UPS-292 stratified charge engine for three different operating conditions, corresponding to overall air-fuel ratios between 22.4 and 61.0. The numerical calculations are performed with KIVA, a multidimensional arbitrary-mesh, finite-difference hydrodynamics program for internal combustion engine applications. The calculations use a mesh of 10,000 computational cells. Each operating condition is calculated from intake valve closure at 118/sup 0/ BTDC to 90/sup 0/ ATDC and requires approximately three hours of CRAY-XMP computer time. Combustion occurs primarily in the wake of the spark plug, and to include the effects of the spark plug on the flow field, we use a novel internal obstacle treatment. The methodology, in which internal obstacles are represented by computational particles, promises to be applicable to the calculation of the flows around intake and exhaust valves.
Numerical simulation study on fluid dynamics of plasma window using argon
Huang, S.; Zhu, K.; Shi, B. L.; Lu, Y. R.; Hershcovitch, A.; Yang, L.; Zhang, X. Y.; Wei, G. D.
2013-07-15
In this paper, a numerical 2D FLUENT-based magneto-hydrodynamic model has been developed to investigate the arc and flow field of plasma window, which is used as a windowless vacuum sealing device. The gas inlet, arc creation-developing and plasma expansion segments are all incorporated together in the integral model. An axis-symmetry cathode structure (hollow cathode) is used in the model. Current distribution of the arc is presented and discussed. The temperature, velocity, and pressure field are presented to show the physical mechanisms for the high pressure gap within the plasma window. Flow acceleration and viscosity effect are concluded as the main reasons for the pressure drop. The result for the pressure distribution in the cylindrical tube section has a good agreement with the analytical model. The validation for the sealing ability of plasma window is verified.
Romero, C.; Benner, J.C.; Berkbigler, L.W.
1997-02-01
Los Alamos National Laboratory is currently in the design phase of a large Containment System that will be used to contain hydrodynamic experiments. The system in question is being designed to elastically withstand a 50 kg internal high explosive (PBX-9501) detonation. A one-tenth scaled model of the containment system was fabricated and used to obtain experimental results of both pressure loading and strain response. The experimental data are compared with numerical predictions of pressure loading and strain response obtained from an Eulerian hydrodynamic code (MESA-2D) and an explicit, non-linear finite element code (LLNL DYNA3D). The two-dimensional pressure predictions from multiple hydrodynamic simulations are used as loading in the structural simulation. The predicted pressure histories and strain response compare well with experimental results at several locations.
Zarea, M.F.; Toumbas, D.N.; Philibert, C.E.; Deo, I.
1996-12-31
Gas transmission pipe resistance to external damage is a subject of great attention at Gaz de France and in Europe. Existing results cover part of the necessary criteria for the residual life of damaged pipelines, but more knowledge is needed on defect creation. The authors propose to complement existing experimental work which is limited to the explored range of parameters by validated numerical models. The first, simple static denting model aims at optimizing the conditions for calculating the residual stress distribution needed to assess the fatigue life of dents and dents and gouges. The second, more complex dynamic puncture model calculates both the puncture force and the puncture energy for a given pipe, excavator and tooth geometry. These models can contribute to enhance the external damage prevention policies of transmission pipeline operators.
Numerical simulation of fracture rocks and wave propagation by means of fractal theory
Valle G., R. del
1994-12-31
A numerical approach was developed for the dynamic simulation of fracture rocks and wave propagation. Based on some ideas of percolation theory and fractal growth, a network of particles and strings represent the rock model. To simulate an inhomogeneous medium, the particles and springs have random distributed elastic parameters and are implemented in the dynamic Navier equation. Some of the springs snap with criteria based on the confined stress applied, therefore creating a fractured rock consistent with the physical environment. The basic purpose of this research was to provide a method to construct a fractured rock with confined stress conditions as well as the wave propagation imposed in the model. Such models provide a better understanding of the behavior of wave propagation in fractured media. The synthetic seismic data obtained henceforth, can be used as a tool to develop methods for characterizing fractured rocks by means of geophysical inference.
Numerical renormalization-group study of a Kondo hole in a one-dimensional Kondo insulator
Yu, C.C.
1996-12-01
We have studied a Kondo hole in a one-dimensional Kondo insulator at half-filling using a density matrix formulation of the numerical renormalization group. The Kondo hole introduces midgap states. The spin density introduced by the hole is localized in the vicinity of the hole. It resides primarily in the {ital f} spins for small exchange coupling {ital J} and in the conduction spins for large {ital J}. We present results on the spin gap, charge gap, and neutral gap. The presence of the Kondo hole reduces the charge gap but not the spin gap relative to a Kondo insulator without defects. For small {ital J}, the spin gap is smaller than the charge gap, while for large {ital J}, the spin gap is larger than the charge gap. RKKY interactions are reduced by the Kondo hole as can be seen in the staggered susceptibility. {copyright} {ital 1996 The American Physical Society.}
Real time control and numerical simulation of pipeline subjected to landslide
Cuscuna, S.; Giusti, G.; Gramola, C.
1984-06-01
This paper describes SNAM research activity in the study of behaviour and real-time control of pipelines in landslide areas. The subject can be delt considering three different aspects: 1. Geotechnical characterization of unstable soils. The mechanical parameters of soil and the landslide types are defined; 2. Structural analysis of pipe-soil system. By means of a finite element program it's possible to study the pipe-soil interaction; in this numerical code the soil parameters attend by the non-linear elastic behaviour of pipe restraints. The results of this analysis are the location of the expected most stressed sections of pipe and the global behaviour of pipe inside the soil. 3. Instrumental control. The adoption of a suitable appliance of vibrating wire strain gauges allows the strain control of pipe in time. The aim is to make possible timely interventions in order to guarantee the installation safety.
Wang, Xiaoguang; Zhang, Xiaodong; Wu, Bin; Zhu, Sizheng; Hu, Yemin
2015-02-15
It is well known that electron cyclotron current drive (ECCD) around the o-point of magnetic island along the plasma current direction can stabilize neoclassical tearing modes (NTMs) in tokamak devices. The effects of the radial misalignment between the island and the driven current, the phase misalignment, and the on-duty ratio for modulated current drive on NTM stabilization are studied numerically in this paper. A small radial misalignment is found to significantly decrease the stabilizing effect. When a sufficiently large phase misalignment occurs for the modulated ECCD, the stabilization effect is also reduced a lot. The optimal on-duty ratio of modulated ECCD to stabilize NTMs is found to be in the range of 60%–70%. A larger on-duty ratio than 50% could also mitigate the effect of phase misalignment if it is not too large. There is no benefit from modulation if the phase misalignment is larger than a threshold.
Numerical studies of the flux-to-current ratio method in the KIPT neutron source facility
Cao, Y.; Gohar, Y.; Zhong, Z.
2013-07-01
The reactivity of a subcritical assembly has to be monitored continuously in order to assure its safe operation. In this paper, the flux-to-current ratio method has been studied as an approach to provide the on-line reactivity measurement of the subcritical system. Monte Carlo numerical simulations have been performed using the KIPT neutron source facility model. It is found that the reactivity obtained from the flux-to-current ratio method is sensitive to the detector position in the subcritical assembly. However, if multiple detectors are located about 12 cm above the graphite reflector and 54 cm radially, the technique is shown to be very accurate in determining the k{sub eff} this facility in the range of 0.75 to 0.975. (authors)
Numerical approach for the voloxidation process of an advanced spent fuel conditioning process (ACP)
Park, Byung Heung; Jeong, Sang Mun; Seo, Chung-Seok
2007-07-01
A voloxidation process is adopted as the first step of an advanced spent fuel conditioning process in order to prepare the SF oxide to be reduced in the following electrolytic reduction process. A semi-batch type voloxidizer was devised to transform a SF pellet into powder. In this work, a simple reactor model was developed for the purpose of correlating a gas phase flow rate with an operation time as a numerical approach. With an assumption that a solid phase and a gas phase are homogeneous in a reactor, a reaction rate for an oxidation was introduced into a mass balance equation. The developed equation can describe a change of an outlet's oxygen concentration including such a case that a gas flow is not sufficient enough to continue a reaction at its maximum reaction rate. (authors)
Yamaguchi, Y. [Plasma Research Center, University of Tsukuba (Japan); Ichimura, M. [Plasma Research Center, University of Tsukuba (Japan); Higaki, H. [Plasma Research Center, University of Tsukuba (Japan); Kakimoto, S. [Plasma Research Center, University of Tsukuba (Japan); Ide, K. [Plasma Research Center, University of Tsukuba (Japan); Inoue, D. [Plasma Research Center, University of Tsukuba (Japan); Nagai, H. [Plasma Research Center, University of Tsukuba (Japan); Nakagome, K. [Plasma Research Center, University of Tsukuba (Japan); Fukuyama, A. [Kyoto University (Japan); Cho, T. [Plasma Research Center, University of Tsukuba (Japan)
2005-01-15
The numerical analysis is performed with two dimensional wave code for controlling the eigenmode formation of fast Alfven waves in the GAMMA 10 central cell. The plasma production by fast waves depends on the wave excitation in the plasma. Eigenmodes are strongly formed when the boundary conditions in the axial and radial directions are satisfied. As the optimum density for the formation of eigenmode exists discretely, the density is clamped at the value where the eigenmode is strongly formed. For the higher density plasma production, the eigenmodes must be continuously excited as the density increases. It is found that the almost continuous excitation of eigenmodes can be realized by using two waves with different frequencies at the same time.
Defect reaction network in Si-doped InAs. Numerical predictions.
Schultz, Peter A.
2015-05-01
This Report characterizes the defects in the def ect reaction network in silicon - doped, n - type InAs predicted with first principles density functional theory. The reaction network is deduced by following exothermic defect reactions starting with the initially mobile interstitial defects reacting with common displacement damage defects in Si - doped InAs , until culminating in immobile reaction p roducts. The defect reactions and reaction energies are tabulated, along with the properties of all the silicon - related defects in the reaction network. This Report serves to extend the results for the properties of intrinsic defects in bulk InAs as colla ted in SAND 2013 - 2477 : Simple intrinsic defects in InAs : Numerical predictions to include Si - containing simple defects likely to be present in a radiation - induced defect reaction sequence . This page intentionally left blank
Direct numerical simulation of turbulent flow in a rotating square duct
Dai, Yi-Jun; Huang, Wei-Xi Xu, Chun-Xiao; Cui, Gui-Xiang
2015-06-15
A fully developed turbulent flow in a rotating straight square duct is simulated by direct numerical simulations at Re{sub ?} = 300 and 0 ? Ro{sub ?} ? 40. The rotating axis is parallel to two opposite walls of the duct and normal to the main flow. Variations of the turbulence statistics with the rotation rate are presented, and a comparison with the rotating turbulent channel flow is discussed. Rich secondary flow patterns in the cross section are observed by varying the rotation rate. The appearance of a pair of additional vortices above the pressure wall is carefully examined, and the underlying mechanism is explained according to the budget analysis of the mean momentum equations.
Numerical simulation to study the transient self focusing of laser beam in plasma
Sharma, R. P.; Hussain, Saba Gaur, Nidhi
2015-02-15
In this paper, we present the numerical simulation for the coupled system of equations governing the dynamics of laser and Ion Acoustic Wave (IAW) in a collisionless plasma, when the coupling between the waves is through ponderomotive non-linearity. The nonlinear evolution of the laser beam is studied when the pump laser is perturbed by a periodic perturbation. By changing the perturbation wave number, we have studied its effect on the nonlinear evolution pattern of laser beam. In order to have a physical insight into the nonlinear dynamics of laser beam evolution in time and space, we have studied the laser and IAW spectra containing spatial harmonics. The magnitude of these harmonics changes with time and leads to time dependent localization of laser beam in spatial domain. The nonlinear dynamics of this localization is investigated in detail by using simulation and a semi-analytical model.
A Numerical Algorithm for the Solution of a Phase-Field Model of Polycrystalline Materials
Dorr, M R; Fattebert, J; Wickett, M E; Belak, J F; Turchi, P A
2008-12-04
We describe an algorithm for the numerical solution of a phase-field model (PFM) of microstructure evolution in polycrystalline materials. The PFM system of equations includes a local order parameter, a quaternion representation of local orientation and a species composition parameter. The algorithm is based on the implicit integration of a semidiscretization of the PFM system using a backward difference formula (BDF) temporal discretization combined with a Newton-Krylov algorithm to solve the nonlinear system at each time step. The BDF algorithm is combined with a coordinate projection method to maintain quaternion unit length, which is related to an important solution invariant. A key element of the Newton-Krylov algorithm is the selection of a preconditioner to accelerate the convergence of the Generalized Minimum Residual algorithm used to solve the Jacobian linear system in each Newton step. Results are presented for the application of the algorithm to 2D and 3D examples.
Numerical study of the Columbia high-beta device: Torus-II
Izzo, R.
1981-01-01
The ionization, heating and subsequent long-time-scale behavior of the helium plasma in the Columbia fusion device, Torus-II, is studied. The purpose of this work is to perform numerical simulations while maintaining a high level of interaction with experimentalists. The device is operated as a toroidal z-pinch to prepare the gas for heating. This ionization of helium is studied using a zero-dimensional, two-fluid code. It is essentially an energy balance calculation that follows the development of the various charge states of the helium and any impurities (primarily silicon and oxygen) that are present. The code is an atomic physics model of Torus-II. In addition to ionization, we include three-body and radiative recombination processes.
Bitter, M.; Fraenkel, B.; Hill, K.W.; Hsuan, H.; von Goeler, S. )
1995-01-01
Line brightness calculations for the parameters at the International Thermonuclear Experimental Reactor (ITER) and results from recent experiments on the Tokamak Fusion Test Reactor (TFTR) indicate that time-resolved measurements of the central ion temperature and other central plasma parameters should be feasible on ITER with nonperturbing amounts of krypton. Since the measurements will have to be performed in the presence of high fluxes of 14-MeV neutrons from DT-fusion reactions, the size of windows, apertures and x-ray detectors must be as small as possible. Under these conditions, the use of doubly focussing crystals can significantly enhance the signal-to-noise ratio. This paper describes numerical studies of the focussing properties of spherically bent crystals and their application to ITER.
The Effect of Element Formulation on the Prediction of Boost Effects in Numerical Tube Bending
Bardelcik, A.; Worswick, M.J.
2005-08-05
This paper presents advanced FE models of the pre-bending process to investigate the effect of element formulation on the prediction of boost effects in tube bending. Tube bending experiments are conducted with 3'' (OD) IF (Interstitial-Free) steel tube on a fully instrumented Eagle EPT-75 servo-hydraulic mandrel-rotary draw tube bender. Experiments were performed in which the bending boost was varied at three levels and resulted in consistent trends in the strain and thickness distribution within the pre-bent tubes. A numerical model of the rotary draw tube bender was used to simulate pre-bending of the IF tube with the three levels of boost from the experiments. To examine the effect of element formulation on the prediction of boost, the tube was modeled with shell and solid elements. Both models predicted the overall strain and thickness results well, but showed different trends in each of the models.
Numerical simulation of a thermoacoustic refrigerator. 2: Stratified flow around the stack
Worlikar, A.S.; Knio, O.M.; Klein, R.
1998-08-10
The unsteady, two-dimensional, thermally stratified flow in the neighborhood of an idealized thermoacoustic stack is analyzed using a low-Mach-number model that extends the adiabatic flow scheme developed in part 1 (Journal of Computational Physics 127, 424 (1996)). The extension consists of incorporation of numerical solvers for the energy equations in the fluid and the stack plates, and construction and implementation of fast Poisson solver for the velocity potential based on a domain decomposition/boundary Green`s function technique. The unsteady computations are used to predict the steady-state, acoustically generated temperature gradient across a two-dimensional couple and to analyze its dependence on the amplitude of the prevailing resonant wave. Computed results are compared to theoretical predictions and experimental data.
Numerical modeling of pulsed laser-material interaction and of laser plume dynamics
Zhao, Qiang; Shi, Yina
2015-03-10
We have developed two-dimensional Arbitrary Lagrangian Eulerian (ALE) code which is used to study the physical processes, the plasma absorption, the crater profile, and the temperature distribution on metallic target and below the surface. The ALE method overcomes problems with Lagrangian moving mesh distortion by mesh smoothing and conservative quantities remapping from Lagrangian mesh to smoothed one. A new second order accurate diffusion solver has been implemented for the thermal conduction and radiation transport on distorted mesh. The results of numerical simulation of pulsed laser ablation are presented. The influences of different processes, such as time evolution of the surface temperature, interspecies interactions (elastic collisions, recombination-dissociation reaction), interaction with an ambient gas are examined. The study presents particular interest for the analysis of experimental results obtained during pulsed laser ablation.
Ward, Andy L.; Oostrom, Mart; Bacon, Diana H.
2008-02-04
Apart from source excavation, the options available for the remediation of vadose zone metal and radionuclide contaminants beyond the practical excavation depth (0 to 15 m) are quite limited. Of the available technologies, very few are applicable to the deep vadose zone with the top-ranked candidate being soil desiccation. An expert panel review of the work on infiltration control and supplemental technologies identified a number of knowledge gaps that would need to be overcome before soil desiccation could be deployed. The report documents some of the research conducted in the last year to fill these knowledge gaps. This work included 1) performing intermediate-scale laboratory flow cell experiments to demonstrate the desiccation process, 2) implementing a scalable version of Subsurface Transport Over Multiple PhasesWater-Air-Energy (STOMP-WAE), and 3) performing numerical experiments to identify the factors controlling the performance of a desiccation system.
Numerical analysis for finite-range multitype stochastic contact financial market dynamic systems
Yang, Ge; Wang, Jun; Fang, Wen
2015-04-15
In an attempt to reproduce and study the dynamics of financial markets, a random agent-based financial price model is developed and investigated by the finite-range multitype contact dynamic system, in which the interaction and dispersal of different types of investment attitudes in a stock market are imitated by viruses spreading. With different parameters of birth rates and finite-range, the normalized return series are simulated by Monte Carlo simulation method and numerical studied by power-law distribution analysis and autocorrelation analysis. To better understand the nonlinear dynamics of the return series, a q-order autocorrelation function and a multi-autocorrelation function are also defined in this work. The comparisons of statistical behaviors of return series from the agent-based model and the daily historical market returns of Shanghai Composite Index and Shenzhen Component Index indicate that the proposed model is a reasonable qualitative explanation for the price formation process of stock market systems.
Numerical studies on the performance of a flow distributor in tank
Shin, Soo Jai Kim, Young In; Ryu, Seungyeob; Bae, Youngmin; Kim, Keung Koo
2015-03-10
Flow distributors are generally observed in several nuclear power plants. During core make-up tank (CMT) injection into the reactor, the condensation and thermal stratification are observed in the CMT, and rapid condensation disturbs the injection operation. To reduce the condensation phenomena in the tank, CMT was equipped with a flow distributor. The optimal design of the flow distributor is very important to ensure the structural integrity the CMT and its safe operation during certain transient or accident conditions. In the present study, we numerically investigated the performance of a flow distributor in tank with different shape factors such as the total number of holes, pitch-to-hole diameter ratios, diameter of the hole, and the area ratios. These data will contribute to a design of the flow distributor.
Numerical study of nucleation and growth of bubbles in viscous magmas
Toramaru, A.
1995-02-01
The nucleation and growth processes of bubbles in viscous magmas with a constant decompression rate have been numerically investigated based on a formation which accounts for effects of viscosity, as well as diffusivity, interfacial tension, and decompression rate. The numerical solutions show two regimes in the nucleation and growth process, a diffusion-controlled regime and a viscosity-controlled regime, mainly depending on the decompression rate, initial saturation pressure and viscosity. The basic mechanism common to both regimes is that growth governs nucleation through depletion of degassing components. In basaltic eruptions the vesiculation is essentially controlled by diffusion, and the viscosity-controlled regime is limited to very high decompression rate and very small water content. When andesitic magma saturated by water at 10 MPa is decompressed through the propagation of rarefraction wave induced by a landslide, as took place in the Mount St. Helens 1980 eruption, the vesiculation is controlled by the viscosity up to 100 m depth. On the other hand, in a rhyolitic magma for the same situation, vesiculation is controlled by the viscosity over the whole depth of the magma column. In the viscosity-controlled regime, the vesicularity may be 90% or less as seen in silicic pumice, whereas in the diffusion-controlled regime the vesicularity equals or exceeds 98% such as in reticulite in Hawaiian basalt. An observed variation of the number density of bubbles by several orders of magnitude in plinian eruptions and the correlation with the SiO2 content can be attributed approximately to the dependence of diffusivity of viscosity on SiO2 content and temperature, assuming the apparent correlation between SiO2 content and temperature of magma.
Dryer, Frederick L.
2009-04-10
This project was an integrated experimental/numerical effort to study pyrolysis and oxidation reactions and mechanisms for small-molecule hydrocarbon structures under conditions representative of combustion environments. The experimental aspects of the work were conducted in large-diameter flow reactors, at 0.3 to 18 atm pressure, 500 to 1100 K temperature, and 10^{-2} to 2 seconds reaction time. Experiments were also conducted to determine reference laminar flame speeds using a premixed laminar stagnation flame experiment and particle image velocimetry, as well as pressurized bomb experiments. Flow reactor data for oxidation experiments include: (1)adiabatic/isothermal species time-histories of a reaction under fixed initial pressure, temperature, and composition; to determine the species present after a fixed reaction time, initial pressure; (2)species distributions with varying initial reaction temperature; (3)perturbations of a well-defined reaction systems (e.g. CO/H_{2}/O_{2} or H_{2}/O_{2})by the addition of small amounts of an additive species. Radical scavenging techniques are applied to determine unimolecular decomposition rates from pyrolysis experiments. Laminar flame speed measurements are determined as a function of equivalence ratio, dilution, and unburned gas temperature at 1 atm pressure. Hierarchical, comprehensive mechanistic construction methods were applied to develop detailed kinetic mechanisms which describe the measurements and literature kinetic data. Modeling using well-defined and validated mechanisms for the CO/H_{2}/Oxidant systems and perturbations of oxidation experiments by small amounts of additives were also used to derive absolute reaction rates and to investigate the compatibility of published elementary kinetic and thermochemical information. Numerical tools were developed and applied to assess the importance of individual elementary reactions to the predictive performance of the
Dong, S.
2015-02-15
We present a family of physical formulations, and a numerical algorithm, based on a class of general order parameters for simulating the motion of a mixture of N (N⩾2) immiscible incompressible fluids with given densities, dynamic viscosities, and pairwise surface tensions. The N-phase formulations stem from a phase field model we developed in a recent work based on the conservations of mass/momentum, and the second law of thermodynamics. The introduction of general order parameters leads to an extremely strongly-coupled system of (N−1) phase field equations. On the other hand, the general form enables one to compute the N-phase mixing energy density coefficients in an explicit fashion in terms of the pairwise surface tensions. We show that the increased complexity in the form of the phase field equations associated with general order parameters in actuality does not cause essential computational difficulties. Our numerical algorithm reformulates the (N−1) strongly-coupled phase field equations for general order parameters into 2(N−1) Helmholtz-type equations that are completely de-coupled from one another. This leads to a computational complexity comparable to that for the simplified phase field equations associated with certain special choice of the order parameters. We demonstrate the capabilities of the method developed herein using several test problems involving multiple fluid phases and large contrasts in densities and viscosities among the multitude of fluids. In particular, by comparing simulation results with the Langmuir–de Gennes theory of floating liquid lenses we show that the method using general order parameters produces physically accurate results for multiple fluid phases.
Experimental and numerical investigation of hydrogen combustion in a supersonic flow
Segal, C.
1991-01-01
Supersonic combustion ramjet, or SCRAMJET, engines are currently being evaluated for the propulsion of hypersonic vehicles. A unique supersonic wind tunnel facility has been built at the Aerospace Research Laboratory to simulate the operation of a SCRAMJET over a range of Mach numbers of 5 to 6.5 and altitudes of 40,000 to 150,000 ft. The tunnel provides high stagnation temperature, clean air in a continuous Mach 2 flow to the combustor where hydrogen is injected and burned. One of the major parameters in the design of the engine is the combustion efficiency, a quantity which is extremely difficult to evaluate directly. Wall pressure and temperature measurements were made on a model combustor in the ARL facility and a one-dimensional, chemical equilibrium, finite difference model was used to infer combustion efficiency. The initial stagnation temperature was maintained around or below 850 K and an inlet static pressure of 1/2 atm, or less. At these relative low temperatures, thermal choking occurred for relatively low equivalence ratios, limiting this parameter to a maximum of 0.1, depending on the injection configuration. A detailed validation of the analytical model requires extensive knowledge of the physical properties of the flowfield. Since reliable, non-intrusive measurements methods are still under development, the results of the combustion efficiency evaluation were compared with a detailed numerical simulation of the flowfield of interest. The numerical simulation used a 3-D full Navier-Stokes program, which includes a finite rate chemistry model to duplicate one of the experimental cases. The calculations were performed on a CRAY - 2S supercomputer at the National Supercomputer Applications Center at NASA Langley. The solution required 35 CPU hours.
Recent advances in theoretical and numerical studies of wire array Z-pinch in the IAPCM
Ding, Ning Zhang, Yang Xiao, Delong Wu, Jiming Huang, Jun Yin, Li Sun, Shunkai Xue, Chuang Dai, Zihuan Ning, Cheng Shu, Xiaojian Wang, Jianguo Li, Hua
2014-12-15
Fast Z-pinch has produced the most powerful X-ray radiation source in laboratory and also shows the possibility to drive inertial confinement fusion (ICF). Recent advances in wire-array Z-pinch researches at the Institute of Applied Physics and Computational Mathematics are presented in this paper. A typical wire array Z-pinch process has three phases: wire plasma formation and ablation, implosion and the MRT instability development, stagnation and radiation. A mass injection model with azimuthal modulation coefficient is used to describe the wire initiation, and the dynamics of ablated plasmas of wire-array Z-pinches in (r, θ) geometry is numerically studied. In the implosion phase, a two-dimensional(r, z) three temperature radiation MHD code MARED has been developed to investigate the development of the Magneto-Rayleigh-Taylor(MRT) instability. We also analyze the implosion modes of nested wire-array and find that the inner wire-array is hardly affected before the impaction of the outer wire-array. While the plasma accelerated to high speed in the implosion stage stagnates on the axis, abundant x-ray radiation is produced. The energy spectrum of the radiation and the production mechanism are investigated. The computational x-ray pulse shows a reasonable agreement with the experimental result. We also suggest that using alloyed wire-arrays can increase multi-keV K-shell yield by decreasing the opacity of K-shell lines. In addition, we use a detailed circuit model to study the energy coupling between the generator and the Z-pinch implosion. Recently, we are concentrating on the problems of Z-pinch driven ICF, such as dynamic hohlraum and capsule implosions. Our numerical investigations on the interaction of wire-array Z-pinches on foam convertors show qualitative agreements with experimental results on the “Qiangguang I” facility. An integrated two-dimensional simulation of dynamic hohlraum driven capsule implosion provides us the physical insights of wire
NUMERICAL SIMULATIONS OF THE EFFECTS OF CHANGING FUEL FOR TURBINES FIRED BY NATURAL GAS AND SYNGAS
Sabau, Adrian S; Wright, Ian G
2007-01-01
Gas turbines in integrated gasification combined cycle (IGCC) power plants burn a fuel gas (syngas) in which the proportions of hydrocarbons, H2, CO, water vapor, and minor impurity levels may vary significantly from those in natural gas, depending on the input feed to the gasifier and the gasification process. A data structure and computational methodology is presented for the numerical simulation of a turbine thermodynamic cycle for various fuel types, air/fuel ratios, and coolant flow rates. The approach used allowed efficient handling of turbine components and different variable constraints due to fuel changes. Examples are presented for a turbine with four stages and cooled blades. The blades were considered to be cooled in an open circuit, with air provided from appropriate compressor stages. Results are presented for the temperatures of the hot gas, alloy surface (coating-superalloy interface), and coolant, as well as for cooling flow rates. Based on the results of the numerical simulations, values were calculated for the fuel flow rates, airflow ratios, and coolant flow rates required to maintain the superalloy in the first stage blade at the desired temperature when the fuel was changed from natural gas (NG) to syngas (SG). One NG case was conducted to assess the effect of coolant pressure matching between the compressor extraction points and corresponding turbine injection points. It was found that pressure matching is a feature that must be considered for high combustion temperatures. The first series of SG simulations was conducted using the same inlet mass flow and pressure ratios as those for the NG case. The results showed that higher coolant flow rates and a larger number of cooled turbine rows were needed for the SG case. Thus, for this first case, the turbine size would be different for SG than for NG. In order to maintain the original turbine configuration (i.e., geometry, diameters, blade heights, angles, and cooling circuit characteristics) for
Y-12 Work for Others ? a historical perspective, part 2
U.S. Department of Energy (DOE) all webpages (Extended Search)
the prototype SSN-21 full scale propulsor. This 65M task required development of new manufacturing processes that have resulted in basic changes in how the US Navy...
Hwang, Seho; Shin, Jehyun; Kim, Jongman; Won, Byeongho
2015-03-10
Density log is widely applied for a variety of fields such as the petroleum exploration, mineral exploration, and geotechnical survey. The logging condition of density log is normally open holes but there are frequently cased boreholes. The primary calibration curve by slim hole logging manufacturer is normally the calibration curves for the variation of borehole diameter. In this study, we have performed the correction of steel casing effects using numerical and experimental methods. We have performed numerical modeling using the Monte Carlo N-Particle (MCNP) code based on Monte Carlo method, and field experimental method from open and cased hole log. In this study, we used the FDGS (Formation Density Gamma Sonde) for slim borehole with a 100 mCi 137Cs source, three inch borehole and steel casing. The casing effect between numerical and experimental method is well matched.
Martinez-Tossas, Luis A.; Churchfield, Matthew J.; Meneveau, Charles
2015-06-18
In this work we report on results from a detailed comparative numerical study from two Large Eddy Simulation (LES) codes using the Actuator Line Model (ALM). The study focuses on prediction of wind turbine wakes and their breakdown when subject to uniform inflow. Previous studies have shown relative insensitivity to subgrid modeling in the context of a finite-volume code. The present study uses the low dissipation pseudo-spectral LES code from Johns Hopkins University (LESGO) and the second-order, finite-volume OpenFOAMcode (SOWFA) from the National Renewable Energy Laboratory. When subject to uniform inflow, the loads on the blades are found to be unaffected by subgrid models or numerics, as expected. The turbulence in the wake and the location of transition to a turbulent state are affected by the subgrid-scale model and the numerics.
Martinez-Tossas, Luis A.; Churchfield, Matthew J.; Meneveau, Charles
2015-06-18
In this work we report on results from a detailed comparative numerical study from two Large Eddy Simulation (LES) codes using the Actuator Line Model (ALM). The study focuses on prediction of wind turbine wakes and their breakdown when subject to uniform inflow. Previous studies have shown relative insensitivity to subgrid modeling in the context of a finite-volume code. The present study uses the low dissipation pseudo-spectral LES code from Johns Hopkins University (LESGO) and the second-order, finite-volume OpenFOAMcode (SOWFA) from the National Renewable Energy Laboratory. When subject to uniform inflow, the loads on the blades are found to bemore » unaffected by subgrid models or numerics, as expected. The turbulence in the wake and the location of transition to a turbulent state are affected by the subgrid-scale model and the numerics.« less
Taylor, G.; Dong, C.; Sun, S.
2010-03-18
A mathematical model for contaminant species passing through fractured porous media is presented. In the numerical model, we combine two locally conservative methods, i.e. mixed finite element (MFE) and the finite volume methods. Adaptive triangle mesh is used for effective treatment of the fractures. A hybrid MFE method is employed to provide an accurate approximation of velocities field for both the fractures and matrix which are crucial to the convection part of the transport equation. The finite volume method and the standard MFE method are used to approximate the convection and dispersion terms respectively. The model is used to investigate the interaction of adsorption with transport and to extract information on effective adsorption distribution coefficients. Numerical examples in different fractured media illustrate the robustness and efficiency of the proposed numerical model.
Numerical Analysis of Coolant Flow and Heat Transfer in ITER Diagnostic First Wall
Khodak, A.; Loesser, G.; Zhai, Y.; Udintsev, V.; Klabacha, J.; Wang, W.; Johnson, D.; Feder, R.
2015-07-24
We performed numerical simulations of the ITER Diagnostic First Wall (DFW) using ANSYS workbench. During operation DFW will include solid main body as well as liquid coolant. Thus thermal and hydraulic analysis of the DFW was performed using conjugated heat transfer approach, in which heat transfer was resolved in both solid and liquid parts, and simultaneously fluid dynamics analysis was performed only in the liquid part. This approach includes interface between solid and liquid part of the systemAnalysis was performed using ANSYS CFX software. CFX software allows solution of heat transfer equations in solid and liquid part, and solution of the flow equations in the liquid part. Coolant flow in the DFW was assumed turbulent and was resolved using Reynolds averaged Navier-Stokes equations with Shear Stress Transport turbulence model. Meshing was performed using CFX method available within ANSYS. The data cloud for thermal loading consisting of volumetric heating and surface heating was imported into CFX Volumetric heating source was generated using Attila software. Surface heating was obtained using radiation heat transfer analysis. Our results allowed us to identify areas of excessive heating. Proposals for cooling channel relocation were made. Additional suggestions were made to improve hydraulic performance of the cooling system.
Numerical Analysis of Coolant Flow and Heat Transfer in ITER Diagnostic First Wall
Khodak, A.; Loesser, G.; Zhai, Y.; Udintsev, V.; Klabacha, J.; Wang, W.; Johnson, D.; Feder, R.
2015-07-24
We performed numerical simulations of the ITER Diagnostic First Wall (DFW) using ANSYS workbench. During operation DFW will include solid main body as well as liquid coolant. Thus thermal and hydraulic analysis of the DFW was performed using conjugated heat transfer approach, in which heat transfer was resolved in both solid and liquid parts, and simultaneously fluid dynamics analysis was performed only in the liquid part. This approach includes interface between solid and liquid part of the systemAnalysis was performed using ANSYS CFX software. CFX software allows solution of heat transfer equations in solid and liquid part, and solution ofmore » the flow equations in the liquid part. Coolant flow in the DFW was assumed turbulent and was resolved using Reynolds averaged Navier-Stokes equations with Shear Stress Transport turbulence model. Meshing was performed using CFX method available within ANSYS. The data cloud for thermal loading consisting of volumetric heating and surface heating was imported into CFX Volumetric heating source was generated using Attila software. Surface heating was obtained using radiation heat transfer analysis. Our results allowed us to identify areas of excessive heating. Proposals for cooling channel relocation were made. Additional suggestions were made to improve hydraulic performance of the cooling system.« less
All-reflective optical target illumination system with high numerical aperture
Sigler, Robert D.
1978-01-01
An all-reflective optical system for providing illumination of a target focal region at high numerical aperture from a pair of co-axially, confluent collimated light beams. A target cavity is defined by a pair of opposed inner ellipsoidal reflectors having respective first focal points within a target region and second focal points at a vertex opening in the opposing reflector. Outwardly of each inner reflector is the opposed combination of a spherical reflector, and an outer generally ellipsoidal reflector having an aberrated first focal point coincident with the focus of the opposing spherical reflector and a second focal point coincident with the second focal point of the opposing inner ellipsoidal reflector through a vertex opening in the spherical reflector. The confluent collimated beams are incident through vertex openings in the outer ellipsoidal reflectors onto respective opposing spherical reflectors. Each beam is reflected by the associated spherical reflector onto the opposing outer ellipsoidal reflector and focused thereby onto the opposing inner ellipsoidal reflector, and then onto the target region.
Xiao, Delong; Sun, Shunkai; Zhao, Yingkui; Ding, Ning; Wu, Jiming; Dai, Zihuan; Yin, Li; Zhang, Yang; Xue, Chuang
2015-05-15
In a dynamic hohlraum driven inertial confinement fusion (ICF) configuration, the target may experience two different kinds of implosions. One is driven by hohlraum radiation ablation, which is approximately symmetric at the equator and poles. The second is caused by the radiating shock produced in Z-pinch dynamic hohlraums, only taking place at the equator. To gain a symmetrical target implosion driven by radiation ablation and avoid asymmetric shock compression is a crucial issue in driving ICF using dynamic hohlraums. It is known that when the target is heated by hohlraum radiation, the ablated plasma will expand outward. The pressure in the shocked converter plasma qualitatively varies linearly with the material temperature. However, the ablation pressure in the ablated plasma varies with 3.5 power of the hohlraum radiation temperature. Therefore, as the hohlraum temperature increases, the ablation pressure will eventually exceed the shock pressure, and the expansion of the ablated plasma will obviously weaken the shock propagation and decrease its velocity after propagating into the ablator plasma. Consequently, longer time duration is provided for the symmetrical target implosion driven by radiation ablation. In this paper these processes are numerically investigated by changing drive currents or varying load parameters. The simulation results show that a critical hohlraum radiation temperature is needed to provide a high enough ablation pressure to decelerate the shock, thus providing long enough time duration for the symmetric fuel compression driven by radiation ablation.
Doty, Michael A.
1997-01-01
A system and method for simultaneously collecting serial number information reports from numerous colliding coded-radio-frequency identity tags. Each tag has a unique multi-digit serial number that is stored in non-volatile RAM. A reader transmits an ASCII coded "D" character on a carrier of about 900 MHz and a power illumination field having a frequency of about 1.6 Ghz. A one MHz tone is modulated on the 1.6 Ghz carrier as a timing clock for a microprocessor in each of the identity tags. Over a thousand such tags may be in the vicinity and each is powered-up and clocked by the 1.6 Ghz power illumination field. Each identity tag looks for the "D" interrogator modulated on the 900 MHz carrier, and each uses a digit of its serial number to time a response. Clear responses received by the reader are repeated for verification. If no verification or a wrong number is received by any identity tag, it uses a second digital together with the first to time out a more extended period for response. Ultimately, the entire serial number will be used in the worst case collision environments; and since the serial numbers are defined as being unique, the final possibility will be successful because a clear time-slot channel will be available.
Doty, M.A.
1997-01-07
A system and method are disclosed for simultaneously collecting serial number information reports from numerous colliding coded-radio-frequency identity tags. Each tag has a unique multi-digit serial number that is stored in non-volatile RAM. A reader transmits an ASCII coded ``D`` character on a carrier of about 900 MHz and a power illumination field having a frequency of about 1.6 Ghz. A one MHz tone is modulated on the 1.6 Ghz carrier as a timing clock for a microprocessor in each of the identity tags. Over a thousand such tags may be in the vicinity and each is powered-up and clocked by the 1.6 Ghz power illumination field. Each identity tag looks for the ``D`` interrogator modulated on the 900 MHz carrier, and each uses a digit of its serial number to time a response. Clear responses received by the reader are repeated for verification. If no verification or a wrong number is received by any identity tag, it uses a second digital together with the first to time out a more extended period for response. Ultimately, the entire serial number will be used in the worst case collision environments; and since the serial numbers are defined as being unique, the final possibility will be successful because a clear time-slot channel will be available. 5 figs.
Numerical simulation of laminar plasma dynamos in a cylindrical von Karman flow
Khalzov, I. V.; Brown, B. P.; Schnack, D. D.; Forest, C. B. [University of Wisconsin, 1150 University Avenue, Madison, Wisconsin 53706 (United States); Ebrahimi, F. [University of New Hampshire, 8 College Road, Durham, New Hampshire 03824 (United States)
2011-03-15
The results of a numerical study of the magnetic dynamo effect in cylindrical von Karman plasma flow are presented with parameters relevant to the Madison Plasma Couette Experiment. This experiment is designed to investigate a broad class of phenomena in flowing plasmas. In a plasma, the magnetic Prandtl number Pm can be of order unity (i.e., the fluid Reynolds number Re is comparable to the magnetic Reynolds number Rm). This is in contrast to liquid metal experiments, where Pm is small (so, Re>>Rm) and the flows are always turbulent. We explore dynamo action through simulations using the extended magnetohydrodynamic NIMROD code for an isothermal and compressible plasma model. We also study two-fluid effects in simulations by including the Hall term in Ohm's law. We find that the counter-rotating von Karman flow results in sustained dynamo action and the self-generation of magnetic field when the magnetic Reynolds number exceeds a critical value. For the plasma parameters of the experiment, this field saturates at an amplitude corresponding to a new stable equilibrium (a laminar dynamo). We show that compressibility in the plasma results in an increase of the critical magnetic Reynolds number, while inclusion of the Hall term in Ohm's law changes the amplitude of the saturated dynamo field but not the critical value for the onset of dynamo action.
A numerical study of soot aggregate formation in a laminar coflow diffusion flame
Zhang, Q.; Thomson, M.J. [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario, M5S 3G8 (Canada); Guo, H.; Liu, F.; Smallwood, G.J. [Institute for Chemical Process and Environmental Technology, National Research Council of Canada, Building M-9, 1200 Montreal Road, Ottawa, Ontario, K1A 0R6 (Canada)
2009-03-15
Soot aggregate formation in a two-dimensional laminar coflow ethylene/air diffusion flame is studied with a pyrene-based soot model, a detailed sectional aerosol dynamics model, and a detailed radiation model. The chemical kinetic mechanism describes polycyclic aromatic hydrocarbon formation up to pyrene, the dimerization of which is assumed to lead to soot nucleation. The growth and oxidation of soot particles are characterized by the HACA surface mechanism and pyrene-soot surface condensation. The mass range of the solid soot phase is divided into thirty-five discrete sections and two equations are solved in each section to model the formation of the fractal-like soot aggregates. The coagulation model is improved by implementing the aggregate coagulation efficiency. Several physical processes that may cause sub-unitary aggregate coagulation efficiency are discussed. Their effects on aggregate structure are numerically investigated. The average number of primary soot particles per soot aggregate n{sub p} is found to be a strong function of the aggregate coagulation efficiency. Compared to the available experimental data, n{sub p} is well reproduced with a constant 20% aggregate coagulation efficiency. The predicted axial velocity, OH mole fraction, and C{sub 2}H{sub 2} mole fraction are validated against experimental data in the literature. Reasonable agreements are obtained. Finally, a sensitivity study of the effects of particle coalescence on soot volume fraction and soot aggregate nanostructure is conducted using a coalescence cutoff diameter method. (author)
Numerical simulations of the two-dimensional multimode Richtmyer-Meshkov instability
Thornber, B.; Zhou, Y.
2015-03-15
The two-dimensional Richtmyer-Meshkov instability occurs as shock waves pass through a perturbed material interface, triggering transition to an inhomogeneous turbulence variable density flow. This paper presents a series of large-eddy-simulations of the two dimensional turbulent RM instability and compares the results to the fully three dimensional simulations. There are two aims for this paper, the first is to explore what numerical resolution is required for a statistically converged solution for a two dimensional inhomogeneous flow field. The second aim is to elucidate the key differences in flow physics between the two dimensional and three dimensional Richtmyer-Meshkov instabilities, particularly their asymptotic self-similar regime. Convergence is achieved using 64 independent realisations and grid resolutions up to 4096{sup 2} in the plane. It is shown that for narrowband cases the growth rate θ = 0.48 which is substantially higher than the three-dimensional equivalent. Mix measures are consistently lower compared to three-dimensional, and the kinetic energy distribution is homogeneous at late time. The broadband case has a similar initial growth rate as the three-dimensional case, with a marginally lower θ = 0.63. Mix is similar in magnitude, but is reducing at late time. The spectra in both cases exhibit the dual-cascade expected from two-dimensional turbulence.
Numerical simulation of viscoelastic layer rearrangement in polymer melts using OpenFOAM®
Köpplmayr, Thomas Mayrhofer, Elias
2015-05-22
In addition to their shear-thinning behavior, polymer melts are characterized by first and second normal stress differences, which cause secondary motions. Polymer coextrusion processes involve viscoelastic two-phase flows that influence layer formation. Using polymer melts with different pigmentation makes visible the layers deformed by second normal stress differences. We used a new solver for the OpenFOAM CFD toolbox which handles viscoelastic two-phase flows. A derivative of the volume-of-fluid (VoF) methodology was employed to describe the interface. Different types of polymer melt, such as polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET) were investigated. In a coextrusion process, the less viscous phase usually tends to encapsulate the more viscous one. However, the different viscoelastic properties of the melts also influence interface deformation. The materials were characterized by small-amplitude oscillatory-shear rheometry, and a multimode Giesekus model was used to fit shear viscosity, storage and loss modulus. Our simulations also took interfacial tension into account. Experimental observations and corresponding numerical simulations were found to be in good accordance.
Crandall, Dustin; Bromhal, Grant; Karpyn, Zuleima T.
2010-07-01
Understanding how fracture wall-roughness affects fluid flow is important when modeling many subsurface transport problems. Computed tomography scanning provides a unique view of rock fractures, allowing the measurement of fracture wall-roughness, without destroying the initial rock sample. For this computational fluid dynamics study, we used several different methods to obtain three-dimensional meshes of a computed tomography scanned fracture in Berea sandstone. These volumetric meshes had different wall-roughnesses, which we characterized using the Joint Roughness Coefficient and the fractal dimension of the fracture profiles. We then related these macroscopic roughness parameters to the effective flow through the fractures, as determined from Navier-Stokes numerical models. Thus, we used our fracture meshes to develop relationships between the observed roughness properties of the fracture geometries and flow parameters that are of importance for modeling flow through fractures in field scale models. Fractures with high Joint Roughness Coefficients and fractal dimensions were shown to exhibit tortuous flow paths, be poorly characterized by the mean geometric aperture, and have a fracture transmissivity 35 times smaller than the smoother modeled fracture flows.
Numerical study of the stress state of a deformation twin in magnesium
Arul Kumar, M.; Kanjarla, A. K.; Niezgoda, S. R.; Lebensohn, R. A.; Tomé, C. N.
2014-11-26
Here, we present a numerical study of the distribution of the local stress state associated with deformation twinning in Mg, both inside the twinned domain and in its immediate neighborhood, due to the accommodation of the twinning transformation shear. A full-field elastoviscoplastic formulation based on fast Fourier transformation is modified to include the shear transformation strain associated with deformation twinning. We performed two types of twinning transformation simulations with: (i) the twin completely embedded inside a single crystal and (ii) the twin front terminating at a grain boundary. We show that: (a) the resulting stress distribution is more strongly determined by the shear transformation than by the intragranular character of the twin or the orientation of the neighboring grain; (b) the resolved shear stress on the twin plane along the twin direction is inhomogeneous along the twin–parent interface; and (c) there are substantial differences in the average values of the shear stress in the twin and in the parent grain that contains the twin. We discuss the effect of these local stresses on twin propagation and growth, and the implications of our findings for the modeling of deformation twinning.
Numerical study of the stress state of a deformation twin in magnesium
Arul Kumar, M.; Kanjarla, A. K.; Niezgoda, S. R.; Lebensohn, R. A.; Tomé, C. N.
2014-11-26
Here, we present a numerical study of the distribution of the local stress state associated with deformation twinning in Mg, both inside the twinned domain and in its immediate neighborhood, due to the accommodation of the twinning transformation shear. A full-field elastoviscoplastic formulation based on fast Fourier transformation is modified to include the shear transformation strain associated with deformation twinning. We performed two types of twinning transformation simulations with: (i) the twin completely embedded inside a single crystal and (ii) the twin front terminating at a grain boundary. We show that: (a) the resulting stress distribution is more strongly determinedmore » by the shear transformation than by the intragranular character of the twin or the orientation of the neighboring grain; (b) the resolved shear stress on the twin plane along the twin direction is inhomogeneous along the twin–parent interface; and (c) there are substantial differences in the average values of the shear stress in the twin and in the parent grain that contains the twin. We discuss the effect of these local stresses on twin propagation and growth, and the implications of our findings for the modeling of deformation twinning.« less
Wang, Jingfu Xue, Yanqing; Zhang, Xinxin; Shu, Xinran
2015-10-15
Highlights: • A 3-D model for the MSW incinerator with preheated air was developed. • Gas radiative properties were obtained from a statistical narrow-band model. • Non-gray body radiation model can provide more accurate simulation results. - Abstract: Due to its advantages of high degree volume reduction, relatively stable residue, and energy reclamation, incineration becomes one of the best choices for Municipal Solid Waste (MSW) disposal. However, detailed measurements of temperature and gas species inside a furnace are difficulty by conventional experimental techniques. Therefore, numerical simulation of MSW incineration in the packed bed and gas flow field was applied. In this work, a three dimensional (3-D) model of incinerator system, including flow, heat transfer, detailed chemical mechanisms, and non-gray gas models, was developed. Radiation from the furnace wall and the flame formed above the bed is of importance for drying and igniting the waste. The preheated air with high temperature is used for the MSW combustion. Under the conditions of high temperature and high pressure, MSW combustion produces a variety of radiating gases. The wavelength-depend radiative properties of flame adopted in non-gray radiation model were obtained from a statistical narrow-band model. The influence of radiative heat transfer on temperature, flow field is researched by adiabatic model (without considering radiation), gray radiation model, and non-gray radiation model. The simulation results show that taking into account the non-gray radiation is essential.
Numerical simulation of solar heat absorption within indoor space by means of composite grid method
Omori, Toshiaki; Murakami, Shuzo; Kato, Shinsuke
1997-12-31
This paper describes the method for numerical simulation of solar radiation entering indoor spaces through fenestration. The proposed method can systematically deal with the interception of sunlight by buildings in the outdoor space and obstacles in the indoor space by tracing a large number of particles directed toward the sun. Configuration factors from the fenestration to the sky are also three-dimensionally treated by accounting for outdoor geometries. Distribution of the solar heat absorption in the indoor space is calculated by assuming radiation equilibrium. After the solar heat absorption analysis is carried out, heat transfer analysis in the space is conducted taking account of longwave radiation, convective heat transfer, thermal conduction, and cooling/heating by air conditioning. Then, the indoor thermal environment is evaluated using the resulting temperature distribution of air and indoor surfaces. To evaluate the applicability of these procedures, the thermal environment in a model hall with large glass windows and an overhang is predicted. The analyzed hall is assumed to be located near a tall building.
Interactive statistical-distribution-analysis program utilizing numerical and graphical methods
Glandon, S. R.; Fields, D. E.
1982-04-01
The TERPED/P program is designed to facilitate the quantitative analysis of experimental data, determine the distribution function that best describes the data, and provide graphical representations of the data. This code differs from its predecessors, TEDPED and TERPED, in that a printer-plotter has been added for graphical output flexibility. The addition of the printer-plotter provides TERPED/P with a method of generating graphs that is not dependent on DISSPLA, Integrated Software Systems Corporation's confidential proprietary graphics package. This makes it possible to use TERPED/P on systems not equipped with DISSPLA. In addition, the printer plot is usually produced more rapidly than a high-resolution plot can be generated. Graphical and numerical tests are performed on the data in accordance with the user's assumption of normality or lognormality. Statistical analysis options include computation of the chi-squared statistic and its significance level and the Kolmogorov-Smirnov one-sample test confidence level for data sets of more than 80 points. Plots can be produced on a Calcomp paper plotter, a FR80 film plotter, or a graphics terminal using the high-resolution, DISSPLA-dependent plotter or on a character-type output device by the printer-plotter. The plots are of cumulative probability (abscissa) versus user-defined units (ordinate). The program was developed on a Digital Equipment Corporation (DEC) PDP-10 and consists of 1500 statements. The language used is FORTRAN-10, DEC's extended version of FORTRAN-IV.
Paradkar, B. S.; Cros, B.; Maynard, G.; Mora, P.
2013-08-15
Numerical modeling of laser wakefield electron acceleration inside a gas filled dielectric capillary tube is presented. Guiding of a short pulse laser inside a dielectric capillary tube over a long distance (∼1 m) and acceleration of an externally injected electron bunch to ultra-relativistic energies (∼5-10 GeV) are demonstrated in the quasi-linear regime of laser wakefield acceleration. Two dimensional axisymmetric simulations were performed with the code WAKE-EP (Extended Performances), which allows computationally efficient simulations of such long scale plasma. The code is an upgrade of the quasi-static particle code, WAKE [P. Mora and T. M. Antonsen, Jr., Phys. Plasmas 4, 217 (1997)], to simulate the acceleration of an externally injected electron bunch (including beam loading effect) and propagation of the laser beam inside a dielectric capillary. The influence of the transverse electric field of the plasma wake on the radial loss of the accelerated electrons to the dielectric wall is investigated. The stable acceleration of electrons to multi-GeV energy with a non-resonant laser pulse with a large spot-size is demonstrated.
THREE-DIMENSIONAL NUMERICAL SIMULATIONS OF FAST-TO-ALFVEN CONVERSION IN SUNSPOTS
Felipe, T.
2012-10-20
The conversion of fast waves to the Alfven mode in a realistic sunspot atmosphere is studied through three-dimensional numerical simulations. An upward propagating fast acoustic wave is excited in the high-{beta} region of the model. The new wave modes generated at the conversion layer are analyzed from the projections of the velocity and magnetic field in their characteristic directions, and the computation of their wave energy and fluxes. The analysis reveals that the maximum efficiency of the conversion to the slow mode is obtained for inclinations of 25 Degree-Sign and low azimuths, while the Alfven wave conversions peak at high inclinations and azimuths between 50 Degree-Sign and 120 Degree-Sign . Downward propagating Alfven waves appear at the regions of the sunspot where the orientation of the magnetic field is in the direction opposite to the wave propagation, since at these locations the Alfven wave couples better with the downgoing fast magnetic wave which is reflected due to the gradients of the Alfven speed. The simulations show that the Alfven energy at the chromosphere is comparable to the acoustic energy of the slow mode, being even higher at high inclined magnetic fields.
Zhang, Zhongqiang; Yang, Xiu; Lin, Guang; Karniadakis, George Em
2013-03-01
We consider a piston with a velocity perturbed by Brownian motion moving into a straight tube filled with a perfect gas at rest. The shock generated ahead of the piston can be located by solving the one-dimensional Euler equations driven by white noise using the Stratonovich or Ito formulations. We approximate the Brownian motion with its spectral truncation and subsequently apply stochastic collocation using either sparse grid or the quasi-Monte Carlo (QMC) method. In particular, we first transform the Euler equations with an unsteady stochastic boundary into stochastic Euler equations over a fixed domain with a time-dependent stochastic source term. We then solve the transformed equations by splitting them up into two parts, i.e., a deterministic part and a stochastic part. Numerical results verify the StratonovichEuler and ItoEuler models against stochastic perturbation results, and demonstrate the efficiency of sparse grid and QMC for small and large random piston motions, respectively. The variance of shock location of the piston grows cubically in the case of white noise in contrast to colored noise reported in [1], where the variance of shock location grows quadratically with time for short times and linearly for longer times.
Mitigating cutting-induced plasticity in the contour method, Part 2: Numerical analysis
Muránsky, O.; Hamelin, C. J.; Hosseinzadeh, F.; Prime, M. B.
2016-02-10
Cutting-induced plasticity can have a significant effect on the measurement accuracy of the contour method. The present study examines the benefit of a double-embedded cutting configuration that relies on self-restraint of the specimen, relative to conventional edge-crack cutting configurations. A series of finite element analyses are used to simulate the planar sectioning performed during double-embedded and conventional edge-crack contour cutting configurations. The results of numerical analyses are first compared to measured results to validate the cutting simulations. The simulations are then used to compare the efficacy of different cutting configurations by predicting the deviation of the residual stress profile frommore » an original (pre-cutting) reference stress field, and the extent of cutting-induced plasticity. Comparisons reveal that while the double-embedded cutting configuration produces the most accurate residual stress measurements, the highest levels of plastic flow are generated in this process. As a result, this cutting-induced plastic deformation is, however, largely confined to small ligaments formed as a consequence of the sample sectioning process, and as such it does not significantly affect the back-calculated residual stress field.« less
Numeric-modeling sensitivity analysis of the performance of wind turbine arrays
Lissaman, P.B.S.; Gyatt, G.W.; Zalay, A.D.
1982-06-01
An evaluation of the numerical model created by Lissaman for predicting the performance of wind turbine arrays has been made. Model predictions of the wake parameters have been compared with both full-scale and wind tunnel measurements. Only limited, full-scale data were available, while wind tunnel studies showed difficulties in representing real meteorological conditions. Nevertheless, several modifications and additions have been made to the model using both theoretical and empirical techniques and the new model shows good correlation with experiment. The larger wake growth rate and shorter near wake length predicted by the new model lead to reduced interference effects on downstream turbines and hence greater array efficiencies. The array model has also been re-examined and now incorporates the ability to show the effects of real meteorological conditions such as variations in wind speed and unsteady winds. The resulting computer code has been run to show the sensitivity of array performance to meteorological, machine, and array parameters. Ambient turbulence and windwise spacing are shown to dominate, while hub height ratio is seen to be relatively unimportant. Finally, a detailed analysis of the Goodnoe Hills wind farm in Washington has been made to show how power output can be expected to vary with ambient turbulence, wind speed, and wind direction.
Problems with numerical techniques: Application to mid-loop operation transients
Bryce, W.M.; Lillington, J.N.
1997-07-01
There has been an increasing need to consider accidents at shutdown which have been shown in some PSAs to provide a significant contribution to overall risk. In the UK experience has been gained at three levels: (1) Assessment of codes against experiments; (2) Plant studies specifically for Sizewell B; and (3) Detailed review of modelling to support the plant studies for Sizewell B. The work has largely been carried out using various versions of RELAP5 and SCDAP/RELAP5. The paper details some of the problems that have needed to be addressed. It is believed by the authors that these kinds of problems are probably generic to most of the present generation system thermal-hydraulic codes for the conditions present in mid-loop transients. Thus as far as possible these problems and solutions are proposed in generic terms. The areas addressed include: condensables at low pressure, poor time step calculation detection, water packing, inadequate physical modelling, numerical heat transfer and mass errors. In general single code modifications have been proposed to solve the problems. These have been very much concerned with means of improving existing models rather than by formulating a completely new approach. They have been produced after a particular problem has arisen. Thus, and this has been borne out in practice, the danger is that when new transients are attempted, new problems arise which then also require patching.
Two-dimensional numerical simulation of boron diffusion for pyramidally textured silicon
Ma, Fa-Jun Duttagupta, Shubham; Shetty, Kishan Devappa; Meng, Lei; Hoex, Bram; Peters, Ian Marius; Samudra, Ganesh S.
2014-11-14
Multidimensional numerical simulation of boron diffusion is of great relevance for the improvement of industrial n-type crystalline silicon wafer solar cells. However, surface passivation of boron diffused area is typically studied in one dimension on planar lifetime samples. This approach neglects the effects of the solar cell pyramidal texture on the boron doping process and resulting doping profile. In this work, we present a theoretical study using a two-dimensional surface morphology for pyramidally textured samples. The boron diffusivity and segregation coefficient between oxide and silicon in simulation are determined by reproducing measured one-dimensional boron depth profiles prepared using different boron diffusion recipes on planar samples. The established parameters are subsequently used to simulate the boron diffusion process on textured samples. The simulated junction depth is found to agree quantitatively well with electron beam induced current measurements. Finally, chemical passivation on planar and textured samples is compared in device simulation. Particularly, a two-dimensional approach is adopted for textured samples to evaluate chemical passivation. The intrinsic emitter saturation current density, which is only related to Auger and radiative recombination, is also simulated for both planar and textured samples. The differences between planar and textured samples are discussed.
Terascale Direct Numerical Simulations of Turbulent Combustion: Capabilities and Limits (PReSS Talk)
Yoo, Chun Sang
2009-03-26
The rapid growth in computational capabilities has provided great opportunities for direct numerical simulations (DNS) of turbulent combustion, a type of simulations without any turbulence model. With the help of terascale high performance supercomputing (HPC) resources, we are now able to provide fundamental insight into turbulence-chemistry interaction in simple laboratory-scale turbulent flames with detailed chemistry using three-dimensional (3D) DNS. However, the actual domain size of 3D-DNS is still limited within {approx} O(10 cm{sup 3}) due to its tremendously high grid resolution required to resolve the smallest turbulent length scale as well as flame structures. Moreover, 3D-DNS will require more computing powers to investigate next-generation engines, of which operating conditions will be characterized by higher pressures, lower temperatures, and higher levels of dilution. In this talk, I will discuss the capabilities and limits of DNS of turbulent combustion and present some results of ignition/extinction characteristics of a highly diluted hydrogen flame counter-flowing against heated air. The results of our recent 3D-DNS of a spatially-developing turbulent lifted hydrogen jet flame in heated coflow will also be presented. The 3D-DNS was performed at a jet Reynolds number of 11,000 with {approx} 1 billion grid points, which required 3.5 million CPU hours on Cray XT3/XT4 at Oak Ridge National Laboratories.
Numerical Study of Field-reversed Configurations: The Formation and Ion Spin-up
E.V. Belova; R.C. Davidson; H. Ji; M. Yamada; C.D. Cothran; M.R. Brown; M.J. Schaffer
2005-06-06
Results of three-dimensional numerical simulations of field-reversed configurations (FRCs) are presented. Emphasis of this work is on the nonlinear evolution of magnetohydrodynamic (MHD) instabilities in kinetic FRCs, and the new FRC formation method by counter-helicity spheromak merging. Kinetic simulations show nonlinear saturation of the n = 1 tilt mode, where n is the toroidal mode number. The n = 2 and n = 3 rotational modes are observed to grow during the nonlinear phase of the tilt instability due to the ion spin-up in the toroidal direction. The ion toroidal spin-up is shown to be related to the resistive decay of the internal flux, and the resulting loss of particle confinement. Three-dimensional MHD simulations of counter-helicity spheromak merging and FRC formation show good qualitative agreement with results from the SSX-FRC experiment. The simulations show formation of an FRC in about 20-30 Alfven times for typical experimental parameters. The growth rate of the n = 1 tilt mode is shown to be significantly reduced compared to the MHD growth rate due to the large plasma viscosity and field-line-tying effects.
Numerical evaluation of a fixed-amplitude variable-phase integral.
Lyness, J. N.; Mathematics and Computer Science
2008-01-01
We treat the evaluation of a fixed-amplitude variable-phase integral of the form {integral}{sub a}{sup b} exp[ikG(x)]dx, where G{prime}(x) {ge} 0 and has moderate differentiability in the integration interval. In particular, we treat in detail the case in which G{prime}(a) = G{prime}(b) = 0, but G{double_prime}(a)G{double_prime}(b) < 0. For this, we re-derive a standard asymptotic expansion in inverse half-integer inverse powers of k. This derivation is direct, making no explicit appeal to the theories of stationary phase or steepest descent. It provides straightforward expressions for the coefficients in the expansion in terms of derivatives of G at the end-points. Thus it can be used to evaluate the integrals numerically in cases where k is large. We indicate the generalizations to the theory required to cover cases where the oscillator function G has higher order zeros at either or both end-points, but this is not treated in detail. In the simpler case in which G{prime}(a)G{prime}(b) > 0, the same approach would recover a special case of a recent result due to Iserles and Norsett.
Lima da Silva, M.; Sauvage, E.; Brun, P.; Gagnoud, A.; Fautrelle, Y.; Riva, R.
2013-07-01
The process of vitrification in a cold crucible heated by direct induction is used in the fusion of oxides. Its feature is the production of high-purity materials. The high-level of purity of the molten is achieved because this melting technique excludes the contamination of the charge by the crucible. The aim of the present paper is to analyze the hydrodynamic of the vitrification process by direct induction, with the focus in the effects associated with the interaction between the mechanical stirrer and bubbling. Considering the complexity of the analyzed system and the goal of the present work, we simplified the system by not taking into account the thermal and electromagnetic phenomena. Based in the concept of hydraulic similitude, we performed an experimental study and a numerical modeling of the simplified model. The results of these two studies were compared and showed a good agreement. The results presented in this paper in conjunction with the previous work contribute to a better understanding of the hydrodynamics effects resulting from the interaction between the mechanical stirrer and air bubbling in the cold crucible heated by direct induction. Further works will take into account thermal and electromagnetic phenomena in the presence of mechanical stirrer and air bubbling. (authors)
PROBABILISTIC SIMULATION OF SUBSURFACE FLUID FLOW: A STUDY USING A NUMERICAL SCHEME
Buscheck, Timothy Eric
1980-03-01
There has been an increasing interest in probabilistic modeling of hydrogeologic systems. The classical approach to groundwater modeling has been deterministic in nature, where individual layers and formations are assumed to be uniformly homogeneous. Even in the case of complex heterogeneous systems, the heterogeneities describe the differences in parameter values between various layers, but not within any individual layer. In a deterministic model a single-number is assigned to each hydrogeologic parameter, given a particular scale of interest. However, physically there is no such entity as a truly uniform and homogeneous unit. Single-number representations or deterministic predictions are subject to uncertainties. The approach used in this work models such uncertainties with probabilistic parameters. The resulting statistical distributions of output variables are analyzed. A numerical algorithm, based on axiomatic principles of probability theory, performs arithmetic operations between probability distributions. Two subroutines are developed from the algorithm and incorporated into the computer program TERZAGI, which solves groundwater flow problems in saturated, multi-dimensional systems. The probabilistic computer program is given the name, PROGRES. The algorithm has been applied to study the following problems: one-dimensional flow through homogeneous media, steady-state and transient flow conditions, one-dimensional flow through heterogeneous media, steady-state and transient flow conditions, and two-dimensional steady-stte flow through heterogeneous media. The results are compared with those available in the literature.
GPU accelerated flow solver for direct numerical simulation of turbulent flows
Salvadore, Francesco; Botti, Michela
2013-02-15
Graphical processing units (GPUs), characterized by significant computing performance, are nowadays very appealing for the solution of computationally demanding tasks in a wide variety of scientific applications. However, to run on GPUs, existing codes need to be ported and optimized, a procedure which is not yet standardized and may require non trivial efforts, even to high-performance computing specialists. In the present paper we accurately describe the porting to CUDA (Compute Unified Device Architecture) of a finite-difference compressible Navier–Stokes solver, suitable for direct numerical simulation (DNS) of turbulent flows. Porting and validation processes are illustrated in detail, with emphasis on computational strategies and techniques that can be applied to overcome typical bottlenecks arising from the porting of common computational fluid dynamics solvers. We demonstrate that a careful optimization work is crucial to get the highest performance from GPU accelerators. The results show that the overall speedup of one NVIDIA Tesla S2070 GPU is approximately 22 compared with one AMD Opteron 2352 Barcelona chip and 11 compared with one Intel Xeon X5650 Westmere core. The potential of GPU devices in the simulation of unsteady three-dimensional turbulent flows is proved by performing a DNS of a spatially evolving compressible mixing layer.
Detailed numerical investigation of the Bohm limit in cosmic ray diffusion theory
Hussein, M.; Shalchi, A. E-mail: andreasm4@yahoo.com
2014-04-10
A standard model in cosmic ray diffusion theory is the so-called Bohm limit in which the particle mean free path is assumed to be equal to the Larmor radius. This type of diffusion is often employed to model the propagation and acceleration of energetic particles. However, recent analytical and numerical work has shown that standard Bohm diffusion is not realistic. In the present paper, we perform test-particle simulations to explore particle diffusion in the strong turbulence limit in which the wave field is much stronger than the mean magnetic field. We show that there is indeed a lower limit of the particle mean free path along the mean field. In this limit, the mean free path is directly proportional to the unperturbed Larmor radius like in the traditional Bohm limit, but it is reduced by the factor ?B/B {sub 0} where B {sub 0} is the mean field and ?B the turbulent field. Although we focus on parallel diffusion, we also explore diffusion across the mean field in the strong turbulence limit.
Numerical study of transition to supersonic flows in the edge plasma
Goswami, Rajiv, E-mail: rajiv@ipr.res.in; Artaud, Jean-Franois; Imbeaux, Frdric [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Kaw, Predhiman [Institute for Plasma Research, Bhat, Gandhinagar382428 (India)
2014-07-15
The plasma scrape-off layer (SOL) in a tokamak is characterized by ion flow down a long narrow flux tube terminating on a solid surface. The ion flow velocity along a magnetic field line can be equal to or greater than sonic at the entrance of a Debye sheath or upstream in the presheath. This paper presents a numerical study of the transition between subsonic and supersonics flows. A quasineutral one-dimensional (1D) fluid code has been used for modeling of plasma transport in the SOL along magnetic field lines, both in steady state and under transient conditions. The model uses coupled equations for continuity, momentum, and energy balance with ionization, radiation, charge exchange, and recombination processes. The recycled neutrals are described in the diffusion approximation. Standard Bohm sheath criterion is used as boundary conditions at the material surface. Three conditions conducive for the generation of supersonic flows in SOL plasmas have been explored. It is found that in steady state high (attached) and low (detached) divertor temperatures cases, the role of particle, momentum, and energy loss is critical. For attached case, the appearance of shock waves in the divertor region if the incoming plasma flow is supersonic and its effect on impurity retention is presented. In the third case, plasma expansion along the magnetic field can yield time-dependent supersonic solutions in the quasineutral rarefaction wave. Such situations can arise in the parallel transport of intermittent structures such as blobs and edge localized mode filaments along field lines.
Numerical simulation of the compressor coil of the plasma dynamic accelerator
Thomas, P.
1997-01-01
The plasma dynamic accelerator accelerates a plasma to very high velocities in a coaxial accelerator and then compresses it in a compressor coil, achieving high densities. The axial component of the current distribution, extending from the tip of the coaxial accelerator`s center electrode to the coil turns, causes compressing forces, the radial component yields accelerating forces. The rapid change of the coil current induces azimuthal eddy currents in the plasma that interact with the coil`s magnetic field, again yielding Lorentz forces. Aerodynamic compression may also be an important effect. A new two-dimensional magnetohydrodynamics code is used to investigate which of these effects are really important for the compression. The code allows one to simulate all effects mentioned separately and in combination. In a first step only aerodynamic compression is considered. Then each electromagnetic effect is imposed on the system. Finally, a complete simulation of the compressor coil is performed. The analysis of the results provides new insights in the way the coil operates. This paper presents important aspects of the mathematical model and of the numerical implementation and reports results.
Numerical simulation of gas flow through unsaturated fractured rock at Yucca Mountain, Nevada
Cooper, C.A.
1990-01-01
Numerical analysis is used to identify the physical phenomena associated with barometrically driven gas (air and water vapor) flow through unsaturated fractured rock at Yucca Mountain, Nevada. Results from simple finite difference simulations indicate that for a fractured rock scenario, the maximum velocity of air out of an uncased 10 cm borehole is 0.002 m s{sub {minus}1}. An equivalent porous medium (EPM) model was incorporated into a multiphase, multicomponent simulator to test more complex conceptual models. Results indicate that for a typical June day, a diurnal pressure wave propagates about 160 m into the surrounding Tiva Canyon hydrogeologic unit. Dry air that enters the formation evaporates water around the borehole which reduces capillary pressure. Multiphase countercurrent flow develops in the vicinity of the hole; the gas phase flows into the formation while the liquid phase flows toward the borehole. The effect occurs within 0.5 m of the borehole. The amount of water vapor leaving the formation during 1 day is 900 cm{sup 3}. This is less than 0.1% of the total recharge into the formation, suggesting that the barometric effect may be insignificant in drying the unsaturated zone. However, gas phase velocities out of the borehole (3 m s{sup {minus}1}), indicating that observed flow rates from wells along the east flank of Yucca Mountain were able to be simulated with a barometric model.