National Library of Energy BETA

Sample records for range convection oven

  1. Toward the Long-range Prediction of Severe Convective Windstorms

    E-Print Network [OSTI]

    Kuligowski, Bob

    Toward the Long-range Prediction of Severe Convective Windstorms Ken Pryor Department review pertaining to severe convective windstorm (SCW) structure and evolution. · Identify potential for the development of a long-range SCW prediction technique. #12;Background · Severe windstorms resulting from large

  2. Technical support document: Energy efficiency standards for consumer products: Room air conditioners, water heaters, direct heating equipment, mobile home furnaces, kitchen ranges and ovens, pool heaters, fluorescent lamp ballasts and television sets. Volume 1, Methodology

    SciTech Connect (OSTI)

    Not Available

    1993-11-01

    The Energy Policy and Conservation Act (P.L. 94-163), as amended, establishes energy conservation standards for 12 of the 13 types of consumer products specifically covered by the Act. The legislation requires the Department of Energy (DOE) to consider new or amended standards for these and other types of products at specified times. DOE is currently considering amending standards for seven types of products: water heaters, direct heating equipment, mobile home furnaces, pool heaters, room air conditioners, kitchen ranges and ovens (including microwave ovens), and fluorescent light ballasts and is considering establishing standards for television sets. This Technical Support Document presents the methodology, data, and results from the analysis of the energy and economic impacts of the proposed standards. This volume presents a general description of the analytic approach, including the structure of the major models.

  3. Convection?

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit the followingConcentratingPortal ControllingConvection feedbacks in a What

  4. Orographic Modification of Convection and Flow Kinematics by the Oregon Coast Range and Cascades during IMPROVE-2

    E-Print Network [OSTI]

    Houze Jr., Robert A.

    of research. The analysis of recent field datasets has revealed many complex physical mechanisms that canOrographic Modification of Convection and Flow Kinematics by the Oregon Coast Range and Cascades 2008) ABSTRACT This paper describes the kinematic and precipitation evolution accompanying the passage

  5. Covered Product Category: Commercial Ovens

    Broader source: Energy.gov [DOE]

    The Federal Energy Management Program (FEMP) provides acquisition guidance for commercial ovens, which is a product category covered by the ENERGY STAR program.

  6. Coke oven gas injection to blast furnaces

    SciTech Connect (OSTI)

    Maddalena, F.L.; Terza, R.R.; Sobek, T.F.; Myklebust, K.L. [U.S. Steel, Clairton, PA (United States)

    1995-12-01

    U.S. Steel has three major facilities remaining in Pennsylvania`s Mon Valley near Pittsburgh. The Clairton Coke Works operates 12 batteries which produce 4.7 million tons of coke annually. The Edgar Thomson Works in Braddock is a 2.7 million ton per year steel plant. Irvin Works in Dravosburg has a hot strip mill and a range of finishing facilities. The coke works produces 120 mmscfd of coke oven gas in excess of the battery heating requirements. This surplus gas is used primarily in steel re-heating furnaces and for boiler fuel to produce steam for plant use. In conjunction with blast furnace gas, it is also used for power generation of up to 90 MW. However, matching the consumption with the production of gas has proved to be difficult. Consequently, surplus gas has been flared at rates of up to 50 mmscfd, totaling 400 mmscf in several months. By 1993, several changes in key conditions provided the impetus to install equipment to inject coke oven gas into the blast furnaces. This paper describes the planning and implementation of a project to replace natural gas in the furnaces with coke oven gas. It involved replacement of 7 miles of pipeline between the coking plants and the blast furnaces, equipment capable of compressing coke oven gas from 10 to 50 psig, and installation of electrical and control systems to deliver gas as demanded.

  7. Oven wall panel construction

    DOE Patents [OSTI]

    Ellison, Kenneth (20 Avondale Cres., Markham, CA); Whike, Alan S. (R.R. #1, Caledon East, both of Ontario, CA)

    1980-04-22

    An oven roof or wall is formed from modular panels, each of which comprises an inner fabric and an outer fabric. Each such fabric is formed with an angle iron framework and somewhat resilient tie-bars or welded at their ends to flanges of the angle irons to maintain the inner and outer frameworks in spaced disposition while minimizing heat transfer by conduction and permitting some degree of relative movement on expansion and contraction of the module components. Suitable thermal insulation is provided within the module. Panels or skins are secured to the fabric frameworks and each such skin is secured to a framework and projects laterally so as slidingly to overlie the adjacent frame member of an adjacent panel in turn to permit relative movement during expansion and contraction.

  8. Ovenized microelectromechanical system (MEMS) resonator

    DOE Patents [OSTI]

    Olsson, Roy H; Wojciechowski, Kenneth; Kim, Bongsang

    2014-03-11

    An ovenized micro-electro-mechanical system (MEMS) resonator including: a substantially thermally isolated mechanical resonator cavity; a mechanical oscillator coupled to the mechanical resonator cavity; and a heating element formed on the mechanical resonator cavity.

  9. Solar Pizza Oven Box k - 6

    Office of Environmental Management (EM)

    Ready to Build? BUILD A PIZZA BOX SOLAR OVEN Background The sun is hot enough to bake food. Here's how to make a simple solar oven that gets hot enough to warm up cookies and other...

  10. Ovens

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeeding access toOctoberConsumption (MillionOther EnergyTheOurM206 Mechanical

  11. Impact of a Revised Convective Triggering Mechanism on CAM2 Model Simulations: Results from Short-Range Weather Forecasts

    SciTech Connect (OSTI)

    Xie, S; Boyle, J S; Cederwall, R T; Potter, G L; Zhang, M; Lin, W

    2004-02-19

    This study implements a revised convective triggering condition in the National Center for Atmospheric Research (NCAR) Community Atmosphere Model (CAM2) model to reduce its excessive warm season daytime precipitation over land. The new triggering mechanism introduces a simple dynamic constraint on the initiation of convection that emulates the collective effects of lower level moistening and upward motion of the large-scale circulation. It requires a positive contribution from the large-scale advection of temperature and moisture to the existing positive Convective Available Potential Energy (CAPE) for model convection to start. In contrast, the original convection triggering function in CAM2 assumes that convection is triggered whenever there is positive CAPE, which results in too frequent warm season convection over land arising from strong diurnal variation of solar radiation. We examine the impact of the new trigger on CAM2 simulations by running the climate model in Numerical Weather Prediction (NWP) mode so that more available observations and high-frequency NWP analysis data can be used to evaluate model performance. We show that the modified triggering mechanism has led to considerable improvements in the simulation of precipitation, temperature, moisture, clouds, radiations, surface temperature, and surface sensible and latent heat fluxes when compared to the data collected from the Atmospheric Radiation Measurement (ARM) program at its South Great Plains (SGP) site. Similar improvements are also seen over other parts of the globe. In particular, the surface precipitation simulation has been significantly improved over both the continental United States and around the globe; the overestimation of high clouds in the equatorial tropics has been substantially reduced; and the temperature, moisture, and zonal wind are more realistically simulated. Results from this study also show that some systematic errors in the CAM2 climate simulations can be detected in the early stage of model integration. Examples are the extremely overestimated high clouds in the tropics in the vicinity of ITCZ and the spurious precipitation maximum in the east of the Rockies. This has important implications in studies of these model errors since running the climate model in NWP mode allows us to perform a more in-depth analysis during a short time period where more observations are available and different model errors from various processes have not compensated for the systematic errors.

  12. Energy Efficiency Standards for Microwave Ovens Saves Consumers...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Energy Efficiency Standards for Microwave Ovens Saves Consumers Energy and Updates the Social Cost of Carbon Energy Efficiency Standards for Microwave Ovens Saves Consumers Energy...

  13. New process to avoid emissions: Constant pressure in coke ovens

    SciTech Connect (OSTI)

    Giertz, J.; Huhn, F. [DMT-Gesellschaft fuer Forschung und Pruefung mbH, Essen (Germany). Inst. for Cokemaking and Fuel Technology; Hofherr, K. [Thyssen Stahl AG, Duisburg (Germany)

    1995-12-01

    A chamber pressure regulation (PROven), especially effective in regard to emission control problems of coke ovens is introduced for the first time. Because of the partial vacuum in the collecting main system, it is possible to keep the oven`s raw gas pressure constant on a low level over the full coking time. The individual pressure control for each chamber is assured directly as a function of the oven pressure by an immersion system controlling the flow resistance of the collecting main valve. The latter is a fixed-position design (system name ``FixCup``). By doing away with the interdependence of collecting main pressure and chamber pressure, a parameter seen as a coking constant could not be made variable. This opens a new way to reduce coke oven emissions and simultaneously to prevent the ovens from damage caused by air ingress into the oven.

  14. Making a Solar Oven | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankADVANCED MANUFACTURING OFFICE INDUSTRIALU.S.LeadershipLumiledsofEnergyProgressa Solar Oven Making a

  15. Multiple delivery cesium oven system for negative ion sources

    SciTech Connect (OSTI)

    Bansal, G.; Bhartiya, S.; Pandya, K.; Bandyopadhyay, M.; Singh, M. J.; Soni, J.; Gahlaut, A.; Parmar, K. G.; Chakraborty, A. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

    2012-02-15

    Distribution of cesium in large negative ion beam sources to be operational in ITER, is presently based on the use of three or more cesium ovens, which operate simultaneously and are controlled remotely. However, use of multiple Cs ovens simultaneously is likely to pose difficulties in operation and maintenance of the ovens. An alternate method of Cs delivery, based on a single oven distribution system is proposed as one which could reduce the need of simultaneous operation of many ovens. A proof of principle experiment verifying the concept of a multinozzle distributor based Cs oven has been carried out at Institute for Plasma Research. It is also observed that the Cs flux is not controlled by Cs reservoir temperature after few hours of operation but by the temperature of the distributor which starts behaving as a Cs reservoir.

  16. Prolongation technologies for campaign life of tall oven

    SciTech Connect (OSTI)

    Doko, Yoshiji; Saji, Takafumi; Kitayama, Yoshiteru; Yoshida, Shuhei [Sumitomo Metal Industries, Ltd., Kashima, Ibaraki (Japan). Kashima Steel Works

    1997-12-31

    In Kashima Steel Works, 25-year-old 7-meter-high coke ovens have damage on their walls. However, by using new methods of internal in-situ investigation, ceramic welding for the extended central and upper portions of coke ovens has prolonged the campaign life for over 40 years without large-scale hot repair. In this paper, introduction of these new methods, its application in Kashima and the policy of repairing the tall coke oven are reported.

  17. New Energy Efficiency Standards for Microwave Ovens to Save Consumers...

    Broader source: Energy.gov (indexed) [DOE]

    today that the Energy Department has finalized new energy efficiency standards for microwave ovens that will save consumers nearly 3 billion on their energy bills through 2030....

  18. Simulation of glass flow in an oven Seva Nefedov

    E-Print Network [OSTI]

    Eindhoven, Technische Universiteit

    through the inlets, and inside they are heated by burners. The heating process and the stucture of the oven are designed in such a way, that the melt remains for a period of time in the tank. Several

  19. Pipeline charging of coke ovens with a preheated charge

    SciTech Connect (OSTI)

    Karpov, A.V.; Khadzhioglo, A.V.; Kuznichenko, V.M.

    1983-01-01

    Work to test a pipeline charging method was conducted at the Konetsk Coke Works (a PK-2K coke oven system with a single gas main, oven width 407 mm, height 4300 mm, effective column 20.0 cm/sub 3/). This method consists of transporting the heated coal charge to the ovens through a pipe by means of steam. the charge is transported by high pressure chamber groups, and loaded by means of systems equipped with devices for separation, withdrawal and treatment of the spent steam. The principal goal of the present investigation was to test technical advances in the emission-free charging of preheated charges. The problem was, first, to create a reliable technology for separation of the steam from the charge immediately before loading it into the oven and, second, to provide a total elimination of emissions, thereby protecting the environment against toxic substances.

  20. Reactor Engineering: Experimental Investigation of Alpha Convection

    SciTech Connect (OSTI)

    Usman, Shoaib

    2012-10-12

    Natural convection, Rayleigh-Bernard convection, Transient convection and Conduction convection transition.

  1. Convection towers

    DOE Patents [OSTI]

    Prueitt, M.L.

    1996-01-16

    Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water. 6 figs.

  2. Convection towers

    DOE Patents [OSTI]

    Prueitt, Melvin L. (Los Alamos, NM)

    1995-01-01

    Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.

  3. Convection towers

    DOE Patents [OSTI]

    Prueitt, Melvin L. (Los Alamos, NM)

    1994-01-01

    Convection towers which are capable of cleaning the pollution from large quantities of air and of generating electricity utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity. Other embodiments may also provide fresh water, and operate in an updraft mode.

  4. Convection towers

    DOE Patents [OSTI]

    Prueitt, Melvin L. (Los Alamos, NM)

    1996-01-01

    Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.

  5. A container for heat treating materials in microwave ovens

    DOE Patents [OSTI]

    Holcombe, C.E.; Dykes, N.L.; Kimrey, H.D. Jr.; Mills, J.E.

    1988-01-26

    The efficiency of a microwave oven of a conventional two-source configuration and energy level is increased by providing the oven with a container for housing a refractory material to be treated. The container is formed to top and bottom walls transparent to microwaves while the sidewalls, in a circular configuration, are formed of a nonmetallic material opaque to microwave radiation for reflecting the radiation penetrating the top and bottom walls radially inwardly into the center of the container wherein a casket of heat-insulating material is provided for housing the material to be heat treated. The reflection of the microwave radiation from the sidewalls increases the concentration of the microwaves upon the material being heat treated while the concentration of the microwaves upon the material being heat treated while the casket retains the heat to permit the heating of the material to a substantially higher temperature than achievable in the oven without the container.

  6. Operating and maintenance benefits of automated oven wall temperature measurement

    SciTech Connect (OSTI)

    Leuchtmann, K.P. [Thyssen Still Otto Anlagentechnik GmbH, Bochum (Germany); Hinz, D.; Bergbau, D. [Ruhrkohle Bergbau AG, Bottrop (Germany). Prosper Coking Plant; Platts, M. [Thyssen Still Otto Technical Services, Pittsburgh, PA (United States)

    1997-12-31

    For a very long time and regardless of all shortcomings associated with it, the manual measurement of the heating flue temperature has been the only method of monitoring the temperature prevailing in a coke oven battery and discovering weak points in the heating system. In the course of the last few years a number of automated temperature measuring systems have been developed that are intended to replace or supplement the manual heating flue measurement system. These measuring systems and their advantages/disadvantages are briefly described in this paper. Additionally, operational experience gathered with the oven chamber wall temperature measuring system is discussed in detail.

  7. Convection towers

    DOE Patents [OSTI]

    Prueitt, M.L.

    1994-02-08

    Convection towers which are capable of cleaning the pollution from large quantities of air and of generating electricity utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity. Other embodiments may also provide fresh water, and operate in an updraft mode. 5 figures.

  8. Reducing Energy Consumption on Process Ovens & Oxidation Systems 

    E-Print Network [OSTI]

    Worachek, C.

    2002-01-01

    With the uncertain cost of energy, optimizing the use of air in process dryers, ovens and air pollution control systems is critical to your bottom line. The revived emphasis on air management through the entire process, from plant make-up air...

  9. New packing in absorption systems for trapping benzene from coke-oven gas

    SciTech Connect (OSTI)

    V.V. Grabko; V.M. Li; T.A. Shevchenko; M.A. Solov'ev

    2009-07-15

    The efficiency of benzene removal from coke-oven gas in absorption units OAO Alchevskkoks with new packing is assessed.

  10. Tech. Note ARDB 231 A New Lithium Oven Plasma Source For E-157 Plasma

    E-Print Network [OSTI]

    1 Tech. Note ARDB 231 A New Lithium Oven Plasma Source For E-157 Plasma Wakefield Accelerator Experiments K. A. Marsh and Shuoqin Wang INTRODUCTION A new 1.4 meter long lithium oven has been built source, there are some new diagnostic features for the present oven. Internal thermocouple probes were

  11. Development of advanced technology of coke oven gas drainage treatment

    SciTech Connect (OSTI)

    Higashi, Tadayuki; Yamaguchi, Akikazu; Ikai, Kyozou; Kamiyama, Hisarou; Muto, Hiroshi

    1996-12-31

    In April 1994, commercial-scale application of ozone oxidation to ammonia liquor (which is primarily the water condensing from coke oven gas) to reduce its chemical oxygen demand (COD) was started at the Nagoya Works of Nippon Steel Corporation. This paper deals with the results of technical studies on the optimization of process operating conditions and the enlargement of equipment size and the operating purification system.

  12. Convective heater

    DOE Patents [OSTI]

    Thorogood, Robert M. (Macungie, PA)

    1986-01-01

    A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation.

  13. Automatic coke oven heating control system at Burns Harbor for normal and repair operation

    SciTech Connect (OSTI)

    Battle, E.T.; Chen, K.L. [Bethlehem Steel Corp., Burns Harbor, IN (United States); [Bethlehem Steel Corp., PA (United States)

    1997-12-31

    An automatic heating control system for coke oven batteries was developed in 1985 for the Burns Harbor No. 1 battery and reported in the 1989 Ironmaking Conference Proceedings. The original system was designed to maintain a target coke temperature at a given production level under normal operating conditions. Since 1989, enhancements have been made to this control system so that it can also control the battery heating when the battery is under repair. The new control system has improved heating control capability because it adjusts the heat input to the battery in response to anticipated changes in the production schedule. During a recent repair of this 82 oven battery, the pushing schedule changed from 102 ovens/day to 88 ovens/day, then back to 102 ovens/day, then to 107 ovens/day. During this repair, the control system was able to maintain the coke temperature average standard deviation at 44 F, with a maximum 75 F.

  14. A coke oven model including thermal decomposition kinetics of tar

    SciTech Connect (OSTI)

    Munekane, Fuminori; Yamaguchi, Yukio [Mitsubishi Chemical Corp., Yokohama (Japan); Tanioka, Seiichi [Mitsubishi Chemical Corp., Sakaide (Japan)

    1997-12-31

    A new one-dimensional coke oven model has been developed for simulating the amount and the characteristics of by-products such as tar and gas as well as coke. This model consists of both heat transfer and chemical kinetics including thermal decomposition of coal and tar. The chemical kinetics constants are obtained by estimation based on the results of experiments conducted to investigate the thermal decomposition of both coal and tar. The calculation results using the new model are in good agreement with experimental ones.

  15. Covered Product Category: Commercial Ovens | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:FinancingPetroleum Based Fuels|ProgramsLakeDepartmentEnergy Air-CooledEnergy GasOvens

  16. The Videofil probe, a novel instrument to extend the coke oven service life

    SciTech Connect (OSTI)

    Gaillet, J.P.; Isler, D. [Centre de Pyrolyse de Marienau, Forbach (France)

    1997-12-31

    To prolong the service life of coke oven batteries, the Centre de Pyrolyse de Marienau developed the Videofil probe, a novel instrument to conduct diagnoses and to help repair operations of coke ovens. The Videofil probe is a flexible non-water-cooled endoscope which is used to locate flue wall damage and estimate its importance, to define the oven zones to repair and guide the repair work and to control the quality of the repair work and its durability.

  17. X-ray evaluation of coke-oven gas line deposits

    SciTech Connect (OSTI)

    Swain, Y.T.

    1983-08-01

    Control of coke-oven gas pipeline deposits has been facilitated through the use of an X-ray technique that provides quantitative data without disrupting plant operations.

  18. Factors affecting coking pressures in tall coke ovens

    SciTech Connect (OSTI)

    Grimley, J.J.; Radley, C.E. [British Steel plc, Scunthorpe (United Kingdom). Scunthorpe Works

    1995-12-01

    The detrimental effects of excessive coking pressures, resulting in the permanent deformation of coke oven walls, have been recognized for many years. Considerable research has been undertaken worldwide in attempts to define the limits within which a plant may safely operate and to quantify the factors which influence these pressures. Few full scale techniques are available for assessing the potential of a coal blend for causing wall damage. Inference of dangerous swelling pressures may be made however by the measurement of the peak gas pressure which is generated as the plastic layers meet and coalesce at the center of the oven. This pressure is referred to in this report as the carbonizing pressure. At the Dawes Lane cokemaking plant of British Steel`s Scunthorpe Works, a large database has been compiled over several years from the regulator measurement of this pressure. This data has been statistically analyzed to provide a mathematical model for predicting the carbonizing pressure from the properties of the component coals, the results of this analysis are presented in this report.

  19. Process Parameters and Energy Use of Gas and Electric Ovens in Industrial Applications 

    E-Print Network [OSTI]

    Kosanovic, D.; Ambs, L.

    2000-01-01

    The study was conducted to evaluate the energy use of natural gas and electric ovens in the production of polymer bearings and components. Tests were conducted to evaluate and compare the performance of natural gas and electric ovens in the process...

  20. Modeling of Microwave Ovens with Perforated Metal Walls Erin M. Kiley and Vadim V. Yakovlev

    E-Print Network [OSTI]

    Yakovlev, Vadim

    Modeling of Microwave Ovens with Perforated Metal Walls Erin M. Kiley and Vadim V. Yakovlev ovens with perforated regions of metal walls. The technique relies on replacement of perforated segments-parameters obtained by FDTD simulation of a perforated sheet in a waveguide. This approach is employed in FDTD

  1. Modelling of a coke oven heating wall M. Landreau, D. Isler, Centre de Pyrolyse de Marienau (CPM)

    E-Print Network [OSTI]

    Boyer, Edmond

    - 1 - Modelling of a coke oven heating wall M. Landreau, D. Isler, Centre de Pyrolyse de Marienau with thermomechanical modelling of a coke oven heating wall. The objective is to define the safe limits of coke oven of walls, roof and larry car, pre-stresses (anchoring system), lateral pressure due to coal pushing A 3D

  2. Influence of entrainment on the thermal stratification in simulations of radiative-convective equilibrium

    E-Print Network [OSTI]

    O'Gorman, Paul Ambrose

    Convective available potential energy (CAPE) is shown to increase rapidly with warming in simulations of radiative-convective equilibrium over a wide range of surface temperatures. The increase in CAPE implies a systematic ...

  3. ARM Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) Product

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Michael

    2014-04-10

    ARM soundings are used to determine Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) and associated properties, using the following relationships;

  4. ARM Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) Product

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Michael

    ARM soundings are used to determine Convective Available Potential Energy (CAPE), Convective Inhibition (CIN) and associated properties, using the following relationships;

  5. Additional Steam Traps Increase Production of a Drum Oven at a Petroleum Jelly Plant

    SciTech Connect (OSTI)

    Not Available

    2002-03-01

    Additional steam traps were installed on the drum oven at a petroleum jelly production facility at an ExxonMobil plant in Nigeria. The installation improved heat transfer and saved energy.

  6. Heating control methodology in coke oven battery at Rourkela Steel Plant

    SciTech Connect (OSTI)

    Bandyopadhyay, S.S.; Parthasarathy, L.; Gupta, A.; Bose, P.R.; Mishra, U.

    1996-12-31

    A methodology of heating control was evolved incorporating temperature data generated through infra-red sensor at quenching station and thermocouples specially installed in the gooseneck of coke oven battery No. 3 of RSP. Average temperature of the red-hot coke as pushed helps in diagnosis of the abnormal ovens and in setting the targeted battery temperature. A concept of coke readiness factor (Q) was introduced which on optimization resulted in lowering the specific heat consumption by 30 KCal/Kg.

  7. Development of automatic operation system for coke oven machines at Yawata Works of Nippon Steel Corporation

    SciTech Connect (OSTI)

    Matsunaga, Masao; Uematsu, Hiroshi; Nakagawa, Yoji; Ishiharaguchi, Yuji

    1995-12-01

    The coke plant is a working environment involving heavy dust emissions, high heat and demanding physical labor. The labor-saving operation of the coke plant is an essential issue from the standpoints of not only improvement in working environment, but also reduction in fixed cost by enhancement of labor productivity. Under these circumstances, Nippon Steel has implemented the automation of coke oven machines. The first automatic operation system for coke oven machinery entered service at Oita Works in 1992, followed by the second system at the No. 5 coke oven battery of the coke plant at Yawata Works. The Yawata automatic operation system is characterized by the installation of coke oven machinery to push as many as 140 ovens per day within a short cycle time, such as a preliminary ascension pipe cap opening car and cycle time simulator by the manned operation of the pusher, which is advantageous from the standpoint of investment efficiency, and by the monitoring of other oven machines by the pusher. These measures helped to reduce the manpower requirement to 2 persons per shift from 4 persons per shift. The system entered commercial operation in March, 1994 and has been smoothly working with an average total automatic rate of 97%. Results from the startup to recent operation of the system are reported below.

  8. Radiative-convective instability

    E-Print Network [OSTI]

    Wing, Allison A.

    Radiative-moist-convective equilibrium (RCE) is a simple paradigm for the statistical equilibrium the earth's climate would exhibit in the absence of lateral energy transport. It has generally been assumed that for a given ...

  9. Convective Cloud Lifecycles Lunchtime seminar

    E-Print Network [OSTI]

    Plant, Robert

    Convective Cloud Lifecycles Lunchtime seminar 19th May 2009 Bob Plant Department of Meteorology, University of Reading, UK #12;Introduction Obtain life cycle statistics for clouds in CRM simulations Why Conclusions Convective Cloud Lifecycles ­ p.1/3 #12;Why bother? Convective Cloud Lifecycles ­ p.2/3 #12;Some

  10. Innovative coke oven gas cleaning system for retrofit applications. Volume 1, Public design report

    SciTech Connect (OSTI)

    Not Available

    1994-05-24

    This Public Design Report provides, in a single document, available nonproprietary design -information for the ``Innovative Coke Oven Gas Cleaning System for Retrofit Applications`` Demonstration Project at Bethlehem Steel Corporation`s Sparrows Point, Maryland coke oven by-product facilities. This project demonstrates, for the first time in the United States, the feasibility of integrating four commercially available technologies (processes) for cleaning coke oven gas. The four technologies are: Secondary Gas Cooling, Hydrogen Sulfide and Ammonia Removal, Hydrogen Sulfide and Ammonia Recovery, and Ammonia Destruction and Sulfur Recovery. In addition to the design aspects, the history of the project and the role of the US Department of,Energy are briefly discussed. Actual plant capital and projected operating costs are also presented. An overview of the integration (retrofit) of the processes into the existing plant is presented and is followed by detailed non-proprietary descriptions of the four technologies and their overall effect on reducing the emissions of ammonia, sulfur, and other pollutants from coke oven gas. Narrative process descriptions, simplified process flow diagrams, input/output stream data, operating conditions, catalyst and chemical requirements, and utility requirements are given for each unit. Plant startup provisions, environmental considerations and control monitoring, and safety considerations are also addressed for each process.

  11. A simulation of convective dynamo in the solar convective envelope: Maintenance of the solar-like differential rotation and emerging flux

    SciTech Connect (OSTI)

    Fan, Yuhong; Fang, Fang

    2014-07-01

    We report the results of a magnetohydrodynamic (MHD) simulation of a convective dynamo in a model solar convective envelope driven by the solar radiative diffusive heat flux. The convective dynamo produces a large-scale mean magnetic field that exhibits irregular cyclic behavior with oscillation time scales ranging from about 5 to 15 yr and undergoes irregular polarity reversals. The mean axisymmetric toroidal magnetic field is of opposite signs in the two hemispheres and is concentrated at the bottom of the convection zone. The presence of the magnetic fields is found to play an important role in the self-consistent maintenance of a solar-like differential rotation in the convective dynamo model. Without the magnetic fields, the convective flows drive a differential rotation with a faster rotating polar region. In the midst of magneto-convection, we found the emergence of strong super-equipartition flux bundles at the surface, exhibiting properties that are similar to emerging solar active regions.

  12. Stellar convective cores as dark matter probes

    E-Print Network [OSTI]

    Jordi Casanellas; Isa M. Brandão; Yveline Lebreton

    2015-05-06

    The recent detection of a convective core in a main-sequence solar-type star is used here to test particular models of dark matter (DM) particles, those with masses and scattering cross sections in the range of interest for the DM interpretation of the positive results in several DM direct detection experiments. If DM particles do not effectively self-annihilate after accumulating inside low-mass stars (e.g. in the asymmetric DM scenario) their conduction provides an efficient mechanism of energy transport in the stellar core. For main-sequence stars with masses between 1.1 and 1.3 Msun, this mechanism may lead to the suppression of the inner convective region expected to be present in standard stellar evolution theory. The asteroseismic analysis of the acoustic oscillations of a star can prove the presence/absence of such a convective core, as it was demonstrated for the first time with the Kepler field main-sequence solar-like pulsator, KIC 2009505. Studying this star we found that the asymmetric DM interpretation of the results in the CoGeNT experiment is incompatible with the confirmed presence of a small convective core in KIC 2009505.

  13. Mixed convection transport from an isolated heat source module on a horizontal plate

    SciTech Connect (OSTI)

    Kang, B.H.; Jaluria, Y.; Tewari, S.S. )

    1990-08-01

    An experimental study of the mixed convective heat transfer from an isolated source of finite thickness, located on a horizontal surface in an externally induced forced flow, has been carried out. This problem is of particular interest in the cooling of electronic components and also in the thermal transport associated with various manufacturing systems, such as ovens and furnaces. The temperature distribution in the flow as well as the surface temperature variation are studied in detail. The dependence of the heat transfer rate on the mixed convection parameter and on the thickness of the heated element or source, particularly in the vicinity of the source, is investigated. The results obtained indicate that the heat transfer rate and fluid flow characteristics vary strongly with the mixed convection variables. The transition from a natural convection dominated flow to a forced convection dominated flow is studied experimentally and the basic characteristics of the two regimes determined. This transition has a strong influence on the temperature of the surface and on the heat transfer rate. As expected, the forced convection dominated flow is seen to be significantly more effective in the cooling of a heat dissipating component than a natural convection dominated flow. The location of the maximum temperature on the module surface, which corresponds to the minimum local heat transfer coefficient, is determined and discussed in terms of the underlying physical mechanisms. The results obtained are also compared with these for an element of negligible thickness and the effect of a significant module thickness on the transport is determined. Several other important aspects of fundamental and applied interest are studied in this investigation.

  14. Mathematical modeling of clearance between wall of coke oven and coke cake

    SciTech Connect (OSTI)

    Nushiro, K.; Matsui, T.; Hanaoka, K.; Igawa, K.; Sorimachi, K.

    1995-12-01

    A mathematical model was developed for estimating the clearance between the wall of the coke oven and the coke cake. The prediction model is based on the balance between the contractile force and the coking pressure. A clearance forms when the contractile force exceeds the coking pressure in this model. The contractile force is calculated in consideration of the visco-elastic behavior of the thermal shrinkage of the coke. The coking pressure is calculated considering the generation and dispersion of gas in the melting layer. The relaxation time off coke used in this model was obtained with a dilatometer under the load application. The clearance was measured by the laser sensor, and the internal gas pressure was measured in a test oven. The clearance calculated during the coking process were in good agreement with the experimental results, which supported the validity of the mathematical model.

  15. Operational improvements at Jewell Coal and Coke Company`s non-recovery ovens

    SciTech Connect (OSTI)

    Ellis, C.E.; Pruitt, C.W.

    1995-12-01

    Operational improvements at Jewell Coal and Coke Company over the past five years includes safety and environmental concerns, product quality, equipment availability, manpower utilization, and productivity. These improvements with Jewell`s unique process has allowed Jewell Coal and Coke Company to be a consistent, high quality coke producer. The paper briefly explains Jewell`s unique ovens, their operating mode, improved process control, their maintenance management program, and their increase in productivity.

  16. What Goes Up Must Come Down: The Lifecycle of Convective Clouds (492nd Brookhaven Lecture)

    SciTech Connect (OSTI)

    Jensen, Michael [BNL Environmental Sciences

    2014-02-19

    Some clouds look like cotton balls and others like anvils. Some bring rain, some snow and sleet, and others, just shade. But, whether big and billowy or dark and stormy, clouds affect far more than the weather each day. Armed with measurements of clouds’ updrafts and downdrafts—which resemble airflow in a convection oven—and many other atmospheric interactions, scientists from Brookhaven Lab and other institutions around the world are developing models that are crucial for understanding Earth’s climate and forecasting future climate change. During his lecture, Dr. Jensen provides an overview of the importance of clouds in the Earth’s climate system before explaining how convective clouds form, grow, and dissipate. His discussion includes findings from the Midlatitude Continental Convective Clouds Experiment (MC3E), a major collaborative experiment between U.S. Department of Energy (DOE) and NASA scientists to document precipitation, clouds, winds, and moisture in 3-D for a holistic view of convective clouds and their environment.

  17. Natural convection heat transfer within horizontal spent nuclear fuel assemblies

    SciTech Connect (OSTI)

    Canaan, R.E.

    1995-12-01

    Natural convection heat transfer is experimentally investigated in an enclosed horizontal rod bundle, which characterizes a spent nuclear fuel assembly during dry storage and/or transport conditions. The basic test section consists of a square array of sixty-four stainless steel tubular heaters enclosed within a water-cooled rectangular copper heat exchanger. The heaters are supplied with a uniform power generation per unit length while the surrounding enclosure is maintained at a uniform temperature. The test section resides within a vacuum/pressure chamber in order to subject the assembly to a range of pressure statepoints and various backfill gases. The objective of this experimental study is to obtain convection correlations which can be used in order to easily incorporate convective effects into analytical models of horizontal spent fuel systems, and also to investigate the physical nature of natural convection in enclosed horizontal rod bundles in general. The resulting data consist of: (1) measured temperatures within the assembly as a function of power, pressure, and backfill gas; (2) the relative radiative contribution for the range of observed temperatures; (3) correlations of convective Nusselt number and Rayleigh number for the rod bundle as a whole; and (4) correlations of convective Nusselt number as a function of Rayleigh number for individual rods within the array.

  18. Final environmental information volume for the coke oven gas cleaning project at the Bethlehem Steel Corporation Sparrows Point Plant

    SciTech Connect (OSTI)

    Not Available

    1990-04-24

    Bethelehem Steel Corporation (BSC) is planning to conduct a demonstration project involving an integrated system that can be retrofitted into coke oven gas handling systems to address a variety of environmental and operational factors in a more cost-effective manner. Successful application of this technology to existing US coke plants could: (1) reduce emissions of sulfur dioxide, cyanide, and volatile organic compounds (including benzene) (2) reduce the cost and handling of processing feed chemicals, (3) disposal costs of nuisance by-products and (4) increase reliability and reduce operation/maintenance requirements for coke oven gas desulfurization systems. The proposed system will remove sulfur from the coke oven gas in the form of hydrogen sulfide using the ammonia indigenous to the gas as the primary reactive chemical. Ammonia and hydrogen cyanide are also removed in this process. The hydrogen sulfide removed from the coke oven gas in routed to a modified Claus plant for conversion to a saleable sulfur by-product. Ammonia and hydrogen cyanide will be catalytically converted to hydrogen, nitrogen, carbon dioxide, and carbon monoxide. The tail gas from the sulfur recovery unit is recycled to the coke oven gas stream, upstream of the new gas cleaning system. The proposed demonstration project will be installed at the existing coke oven facilities at BSC's Sparrows Point Plant. This volume describes the proposed actions and the resulting environmental impacts. 21 refs., 19 figs., 9 tabs.

  19. The Phenix ultimate natural convection test

    SciTech Connect (OSTI)

    Gauthe, P.; Pialla, D.; Tenchine, D.; Vasile, A.; Rochwerger, D.

    2012-07-01

    The French sodium cooled fast reactor Phenix was shut down in 2009 after 35 years of operation. Before decommissioning, a final set of tests were performed by the CEA during 9 months. Several topics were involved such as thermal hydraulics, core physics and fuel behaviour. Among these ultimate experiments, two thermal hydraulic tests were performed: an asymmetrical test consisting in a trip of one secondary pump and a natural convection test in the primary circuit. Recognizing the unique opportunity offered by these Phenix ultimate tests, IAEA decided in 2007 to launch a Coordinated Research Project (CRP) devoted to benchmarking analyses with system codes on the Phenix natural convection test. One objective of the natural convection test in Phenix reactor is the assessment of the CATHARE system code for safety studies on future and advanced sodium cooled fast reactors. The aim of this paper is to describe this test, which was performed on June 22-23, 2009, and the associated benchmark specifications for the CRP work. The paper reminds briefly the Phenix reactor with the main physical parameters and the instrumentation used during the natural convection test. After that, the test scenario is described: - initial state at a power of 120 MWth, - test beginning resulting from a manual dry out of the two steam generators, - manual scram, - manual trip on the three primary pumps without back-up by pony motors, - setting and development of natural convection in the primary circuit, in a first phase without significant heat sink in the secondary circuits and in a second phase with significant heat sink in the secondary circuits, by opening the casing of steam generators to create an efficient heat sink, by air natural circulation in the steam generators casing. The benchmark case ends after this second phase, which corresponds to the experimental test duration of nearly 7 hours. The paper presents also the benchmark specifications data supplied by the CEA to all participants of this CRP in order to perform calculations (core, primary circuit, primary pumps, IHX, shutdown system, operating parameters, test scenario and real test conditions). Finally, main test results and analyses are presented including the evolution of the core and of the heat exchangers inlet and outlet temperatures, and some local temperature measurements. The natural convection has been easily set up in the pool type reactor Phenix with different boundary conditions at the secondary side, with or without heat sink. The data obtained during this unique test represent some very useful and precious results for the development of SFR in a wide range of thematic such as numerical methods dedicated to thermal-hydraulics safety analyses (system codes, CFD codes and coupling system and CFD codes) and instrumentation. (authors)

  20. Army Ovens 

    E-Print Network [OSTI]

    Unknown

    2011-09-05

    Tortilla chips were prepared from commercial nixtamalized dry masa flour. They were baked, sun dried and then fried in fresh soybean oil. Control chips were not sun-dried before frying. A commercial batch fryer was used. The effect of solar drying...

  1. Magnetic flux concentrations from turbulent stratified convection

    E-Print Network [OSTI]

    Käpylä, P J; Kleeorin, N; Käpylä, M J; Rogachevskii, I

    2015-01-01

    (abridged) Context: The mechanisms that cause the formation of sunspots are still unclear. Aims: We study the self-organisation of initially uniform sub-equipartition magnetic fields by highly stratified turbulent convection. Methods: We perform simulations of magnetoconvection in Cartesian domains that are $8.5$-$24$ Mm deep and $34$-$96$ Mm wide. We impose either a vertical or a horizontal uniform magnetic field in a convection-driven turbulent flow. Results: We find that super-equipartition magnetic flux concentrations are formed near the surface with domain depths of $12.5$ and $24$ Mm. The size of the concentrations increases as the box size increases and the largest structures ($20$ Mm horizontally) are obtained in the 24 Mm deep models. The field strength in the concentrations is in the range of $3$-$5$ kG. The concentrations grow approximately linearly in time. The effective magnetic pressure measured in the simulations is positive near the surface and negative in the bulk of the convection zone. Its ...

  2. Analysis of Cloud-resolving Simulations of a Tropical Mesoscale Convective System Observed during TWP-ICE: Vertical Fluxes and Draft Properties in Convective and Stratiform Regions

    SciTech Connect (OSTI)

    Mrowiec, Agnieszka A.; Rio, Catherine; Fridlind, Ann; Ackerman, Andrew; Del Genio, Anthony D.; Pauluis, Olivier; Varble, Adam; Fan, Jiwen

    2012-10-02

    We analyze three cloud-resolving model simulations of a strong convective event observed during the TWP-ICE campaign, differing in dynamical core, microphysical scheme or both. Based on simulated and observed radar reflectivity, simulations roughly reproduce observed convective and stratiform precipitating areas. To identify the characteristics of convective and stratiform drafts that are difficult to observe but relevant to climate model parameterization, independent vertical wind speed thresholds are calculated to capture 90% of total convective and stratiform updraft and downdraft mass fluxes. Convective updrafts are fairly consistent across simulations (likely owing to fixed large-scale forcings and surface conditions), except that hydrometeor loadings differ substantially. Convective downdraft and stratiform updraft and downdraft mass fluxes vary notably below the melting level, but share similar vertically uniform draft velocities despite differing hydrometeor loadings. All identified convective and stratiform downdrafts contain precipitation below ~10 km and nearly all updrafts are cloudy above the melting level. Cold pool properties diverge substantially in a manner that is consistent with convective downdraft mass flux differences below the melting level. Despite differences in hydrometeor loadings and cold pool properties, convective updraft and downdraft mass fluxes are linearly correlated with convective area, the ratio of ice in downdrafts to that in updrafts is ~0.5 independent of species, and the ratio of downdraft to updraft mass flux is ~0.5-0.6, which may represent a minimum evaporation efficiency under moist conditions. Hydrometeor loading in stratiform regions is found to be a fraction of hydrometeor loading in convective regions that ranges from ~10% (graupel) to ~90% (cloud ice). These findings may lead to improved convection parameterizations.

  3. Thermal convection with a freely moving top boundary Jin-Qiang Zhong

    E-Print Network [OSTI]

    Zhang, Jun

    Thermal convection with a freely moving top boundary Jin-Qiang Zhong Department of Physics, New; accepted 29 September 2005; published online 22 November 2005 In thermal convection, coherent flow-organization. They range from small-scale thermal plumes that are produced near both the top and the bottom boundaries

  4. Coke oven gas treatment and by-product plant of Magnitogorsk Integrated Iron and Steel Works

    SciTech Connect (OSTI)

    Egorov, V.N.; Anikin, G.J. [Magnitogorsk Integrated Iron and Steel Works, (Russian Federation); Gross, M. [Krupp Koppers GmbH, Essen (Germany)

    1995-12-01

    Magnitogorsk Integrated Iron and Steel Works, Russia, decided to erect a new coke oven gas treatment and by-product plant to replace the existing obsolete units and to improve the environmental conditions of the area. The paper deals with the technological concept and the design requirements. Commissioning is scheduled at the beginning of 1996. The paper describes H{sub 2}S and NH{sub 3} removal, sulfur recovery and ammonia destruction, primary gas cooling and electrostatic tar precipitation, and the distributed control system that will be installed.

  5. Heat distribution by natural convection

    SciTech Connect (OSTI)

    Balcomb, J.D.

    1985-01-01

    Natural convection can provide adequate heat distribution in many situtations that arise in buildings. This is appropriate, for example, in passive solar buildings where some rooms tend to be more strongly solar heated than others or to reduce the number of heating units required in a building. Natural airflow and heat transport through doorways and other internal building apertures is predictable and can be accounted for in the design. The nature of natural convection is described, and a design chart is presented appropriate to a simple, single-doorway situation. Natural convective loops that can occur in buildings are described and a few design guidelines are presented.

  6. Heat distribution by natural convection

    SciTech Connect (OSTI)

    Balcomb, J.D.; Yamaguchi, K.

    1983-01-01

    Natural convection between spaces in a building can play a major role in energy transfer. Two situations are investigated: convection through a single doorway into a remote room, and a convective loop in a two-story house with a south sunspace where a north stairway serves as the return path. A doorway-sizing equation is given for the single-door case. Detailed data are given from the monitoring of airflow in one two-story house and summary data are given for five others. Observations on the nature of the airflow and design guidelines are presented.

  7. Spatially Modulated Structures in Convective Systems

    E-Print Network [OSTI]

    Kao, Hsien-Ching

    2013-01-01

    Mode in Pattern Formation Convection in a horizontal ?uid layer rotating about the vertical or subject

  8. Heat distribution by natural convection

    SciTech Connect (OSTI)

    Balcomb, J.D.

    1985-01-01

    Natural convection can provide adequate heat distribution in many situations that arise in buildings. This is appropriate, for example, in passive solar buildings where some rooms tend to be more strongly solar heated than others. Natural convection can also be used to reduce the number of auxiliary heating units required in a building. Natural airflow and heat transport through doorways and other internal building apertures are predictable and can be accounted for in the design. The nature of natural convection is described, and a design chart is presented appropriate to a simple, single-doorway situation. Experimental results are summarized based on the monitoring of 15 passive solar buildings which employ a wide variety of geometrical configurations including natural convective loops.

  9. Demonstration of a fuel-saving system for paint-curing ovens

    SciTech Connect (OSTI)

    Jensen, W P

    1980-12-01

    Two curing ovens at Roll Coater, Inc. (the Greenfield, Indiana plant) were retrofitted to save fuel and cost. Included in the fuel conserving retrofit was the design, fabrication, and installation of an afterburner for each of the two ovens, piping their combustion products to each of two commonly housed waste heat boilers before discharge from those units to the atmosphere at about 450 F. Depending on the product being run and the coating applied, natural gas requirements have been reduced by 45 to 65% with operation of the zone incinerators only and by as much as 65 to 85% including the effects of both the zone incineration and heat recovery by means of the afterburners and waste heat boilers. A demonstration program on conversion work at the No. 3 line at Greenfield and results are described in Section 2. Section 3 describes the retrofit design and the system construction. System performance (tests and measurements, qualitative performance, maintenance factors, and economic performance) is described in Section 4. Conclusions and recommendations are summarized.

  10. Convective heat flow probe

    DOE Patents [OSTI]

    Dunn, J.C.; Hardee, H.C.; Striker, R.P.

    1984-01-09

    A convective heat flow probe device is provided which measures heat flow and fluid flow magnitude in the formation surrounding a borehole. The probe comprises an elongate housing adapted to be lowered down into the borehole; a plurality of heaters extending along the probe for heating the formation surrounding the borehole; a plurality of temperature sensors arranged around the periphery of the probe for measuring the temperature of the surrounding formation after heating thereof by the heater elements. The temperature sensors and heater elements are mounted in a plurality of separate heater pads which are supported by the housing and which are adapted to be radially expanded into firm engagement with the walls of the borehole. The heat supplied by the heater elements and the temperatures measured by the temperature sensors are monitored and used in providing the desired measurements. The outer peripheral surfaces of the heater pads are configured as segments of a cylinder and form a full cylinder when taken together. A plurality of temperature sensors are located on each pad so as to extend along the length and across the width thereof, with a heating element being located in each pad beneath the temperature sensors. An expansion mechanism driven by a clamping motor provides expansion and retraction of the heater pads and expandable packet-type seals are provided along the probe above and below the heater pads.

  11. FREE CONVECTIVE LAMINAR FLOW WITHIN THE TROMBE WALL CHANNEL

    E-Print Network [OSTI]

    Akbari, H.

    2011-01-01

    Foreign FREE CONVECTIVE LAMINAR FLOW WITHIN THE TROMBE WALLEnergy. -i- FREE CONVECTIVE LAMINAR FLOW WITHIN THE TROMBEABSTRACT Free convective laminar heat transfer between the

  12. A mathematical model for the estimation of flue temperature in a coke oven

    SciTech Connect (OSTI)

    Choi, K.I.; Kim, S.Y.; Suo, J.S.; Hur, N.S.; Kang, I.S.; Lee, W.J.

    1997-12-31

    The coke plants at the Kwangyang works has adopted an Automatic Battery Control (ABC) system which consists of four main parts, battery heating control, underfiring heat and waste gas oxygen control, pushing and charging schedule and Autotherm-S that measures heating wall temperature during pushing. The measured heating wall temperature is used for calculating Mean Battery Temperature (MBT) which is average temperature of flues for a battery, but the Autotherm-S system can not provide the flue temperatures of an oven. This work attempted to develop mathematical models for the estimation of the flue temperature using the measured heating wall temperature and to examine fitness of the mathematical model for the coke plant operation by analysis of raw gas temperature at the stand pipe. Through this work it is possible to reflect heating wall temperature in calculating MBT for battery heating control without the interruption caused by a maintenance break.

  13. Mineralization of Carbon and Nitrogen from Freeze-and Oven-Dried Plant Material Added to Soil

    E-Print Network [OSTI]

    Florida, University of

    Mineralization of Carbon and Nitrogen from Freeze- and Oven-Dried Plant Material Added to Soil K. K is a common procedure used in mineralization or decompositionstudies. A lab- oratory study was conducted the mineral content of the plant material compared to freeze drying. The total C and N was not significantly

  14. Fig 1. First rotation biomass yield [Mg (oven dry) ha-1 ] of top 5 clones with biomass crop yield trials

    E-Print Network [OSTI]

    Minnesota, University of

    Fig 1. First rotation biomass yield [Mg (oven dry) ha-1 yr-1 ] of top 5 clones with biomass crop about growing SRWCs for bioenergy is that SRWCs may not produce sufficient biomass as a feasible (Fig 1) is well below the required amount of biomass necessary to sustain feasibility of bioenergy

  15. ARM - Midlatitude Continental Convective Clouds

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Mike; Bartholomew, Mary Jane; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    2012-01-19

    Convective processes play a critical role in the Earth's energy balance through the redistribution of heat and moisture in the atmosphere and their link to the hydrological cycle. Accurate representation of convective processes in numerical models is vital towards improving current and future simulations of Earths climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales important to convective processes and therefore must turn to parameterization schemes to represent these processes. In turn, parameterization schemes in cloud-resolving models need to be evaluated for their generality and application to a variety of atmospheric conditions. Data from field campaigns with appropriate forcing descriptors have been traditionally used by modelers for evaluating and improving parameterization schemes.

  16. ARM - Midlatitude Continental Convective Clouds

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Mike; Bartholomew, Mary Jane; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    Convective processes play a critical role in the Earth's energy balance through the redistribution of heat and moisture in the atmosphere and their link to the hydrological cycle. Accurate representation of convective processes in numerical models is vital towards improving current and future simulations of Earths climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales important to convective processes and therefore must turn to parameterization schemes to represent these processes. In turn, parameterization schemes in cloud-resolving models need to be evaluated for their generality and application to a variety of atmospheric conditions. Data from field campaigns with appropriate forcing descriptors have been traditionally used by modelers for evaluating and improving parameterization schemes.

  17. The convective desalination of sea ice

    E-Print Network [OSTI]

    Rees Jones, David

    2014-07-01

    in the interstices of an ice matrix. My focus is on one of the processes by which the salt content of sea ice decreases, namely convective desalination, which is also often called gravity drainage by geophysicists. Modelling convective desalination requires...

  18. "Diffusion of Innovation: Solar Oven Use in Lesotho (Africa)." Grundy, William and Roy Grundy. Advances in Solar Cooking: Proceedings of the 2nd International Conference on Solar Cooker Use and Technology. Shyam S. Nandwani, ed. July 12-15, 1994.

    E-Print Network [OSTI]

    Noble, William Stafford

    "Diffusion of Innovation: Solar Oven Use in Lesotho (Africa)." Grundy, William and Roy Grundy and Technology. Shyam S. Nandwani, ed. July 12-15, 1994. pp. 240-247. 1 DIFFUSION OF INNOVATION: SOLAR OVEN USE of Innovation: Solar Oven Use in Lesotho (Africa)." Grundy, William and Roy Grundy. Advances in Solar Cooking

  19. MESOSCALE CONVECTIVE SYSTEMS Robert A. Houze Jr.

    E-Print Network [OSTI]

    Houze Jr., Robert A.

    MESOSCALE CONVECTIVE SYSTEMS Robert A. Houze Jr. Department of Atmospheric Sciences University; published 31 December 2004. [1] Mesoscale convective systems (MCSs) have regions of both convective and stratiform precipitation, and they develop mesoscale circulations as they mature. The upward motion takes

  20. NATURAL CONVECTION IN ROOM GEOMETRIES

    SciTech Connect (OSTI)

    Gadgil, A.; Bauman, Fred; Kammerud, R.; Ruberg, K.

    1980-06-01

    Computer programs have been developed to numerically simulate natural convection in room geometries in two and three dimensions. The programs have been validated using published data from the literature, results from a full-scale experiment performed at Massachusetts Institute of Technology, and results from a small-scale experiment reported here. One of the computer programs has been used to study the influence of natural convection on the thermal performance of a single thermal zone in a direct-gain passive solar building. The results indicate that the building heating loads calculated by standard building energy analysis methods may be in error by as much as 50% as a result of their use of common assumptions regarding the convection processes which occur in an enclosure. It is also found that the convective heat transfer coefficients between the air and the enclosure surfaces can be substantially different from the values assumed in the standard building energy analysis methods, and can exhibit significant variations across a given surface.

  1. Trials and Tribulations of Ancient Starch Research: An Investigation of Contamination and Earth Ovens at Fort Hood, Texas 

    E-Print Network [OSTI]

    Laurence, Andrew

    2013-04-26

    to conserve fuel while allowing prolonged baking and boiling that renders some foods, including geophytes with complex carbohydrates (such as starch and inulin) and animal fat more readily digestible (Brace 1967, 1980, 2005; Brace et al. 2008; Gott et al... for discussion of earth oven use and animal tissues). Many plants contain lipids and complex carbohydrates, in the form of inulin and/or starch, that cannot be processed by the human body in their natural state and therefore require chemical modifications...

  2. Experience and results of new heating control system of coke oven batteries at Rautaruukki Oy Raahe Steel

    SciTech Connect (OSTI)

    Swanljung, J.; Palmu, P. [Rautaruukki Oy Raahe Steel (Finland)

    1997-12-31

    The latest development and results of the heating control system at Raahe Steel are presented in this paper. From the beginning of coke production in Rautaruukki Oy Raahe Steel (October 1987) the heating control systems have been developed. During the first stage of development work at the coking plant (from year 1987 to 1992), when only the first coke oven battery consisting of 35 ovens was in production, the main progress was in the field of process monitoring. After commissioning of the second stage of the coking plant (November 1992), the development of the new heating control model was started. Target of the project was to develop a dynamic control system which guides the heating of batteries through the various process conditions. Development work took three years and the heating control system was commissioned in the year 1995. Principle of the second generation system is an energy balance calculation, coke end temperature determination and dynamic oven scheduling system. The control is based on simultaneous feedforward and feedback control. The fuzzy logic components were added after about one year experience.

  3. Mesoscale convective complex vs. non-mesoscale convective complex thunderstorms: a comparison of selected meteorological variables 

    E-Print Network [OSTI]

    Hoofard, Michael Eugene

    1986-01-01

    MESOSCALE CONVECTIVE CCMPLLX VS. NON-MESOSCALE CONVECTIVE COMPLEX THUNDERSTORMS: A COMPARISON OF SELECTED METEOROLOGICAL VARIABLES A Thesis MICHAkL EUGENE JJOOFARD Submitted to the Graduate College of Texas AJkM University in partial... fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1986 Major Subj ect: Meteorology MESOSCALE CONVECTIVE COMPLEX VS. NON-MESOSCALE CONVECTIVE COMPLEX THUNDERSTORMS: A COMPARISON OF SELECTED METEOROLOGICAL VARIABLES A Thesis...

  4. Influence of geometry on natural convection in buildings

    SciTech Connect (OSTI)

    White, M.D.; Winn, C.B.; Jones, G.F.; Balcomb, J.D.

    1985-01-01

    Strong free convection airflows occur within passive solar buildings resulting from elevated temperatures of surfaces irradiated by solar energy compared with the cooler surfaces not receiving radiation. The geometry of a building has a large influence on the directions and magnitudes of natural airflows, and thus heat transfer between zones. This investigation has utilized a variety of reduced-scale building configurations to study the effects of geometry on natural convection heat transfer. Similarity between the reduced-scale model and a full-scale passive solar building is achieved by having similar geometries and by replacing air with Freon-12 gas as the model's working fluid. Filling the model with Freon-12 gas results in similarity in Prandtl numbers and Rayleigh numbers based on temperature differences in the range from 10/sup 9/ to 10/sup 11/. Results from four geometries are described with an emphasis placed on the effects of heat loss on zone temperature stratification shifts.

  5. Experimental study of internal wave generation by convection in water

    E-Print Network [OSTI]

    2015-01-01

    study of internal wave generation by convection in waterstudies of internal wave generation by convective turbulenceintermittent generation of internal waves. We also computed

  6. Mixed convection heat transfer from thermal sources mounted on horizontal and vertical surfaces

    SciTech Connect (OSTI)

    Tewari, S.S.; Jaluria, Y. )

    1990-11-01

    An experimental study is carried out on the fundamental aspects of the conjugate, mixed convective heat transfer from two finite width heat sources, which are of negligible thickness, have a uniform heat flux input at the surface, and are located on a flat plate in a horizontal or the vertical orientation. The heat sources are wide in the transverse direction and, therefore, a two-dimensional flow circumstance is simulated. The mixed convection parameter is varied over a fairly wide range to include the buoyancy-dominated and the mixed convection regimes. The circumstances of pure natural convection are also investigated. The convective mechanisms have been studied in detail by measuring the surface temperatures and determining the heat transfer coefficients for the two heated strips, which represent isolated thermal sources. Experimental results indicate that a stronger upstream heat source causes an increase in the surface temperature of a relatively weaker heat source, located downstream, by reducing it convective heat transfer coefficient. The influence of the upstream source is found to be strongly dependent on the surface orientation, especially in the pure natural convection and the buoyancy dominated regimes. The two heat sources are found to be essentially independent on the surface orientation, especially in the pure natural convection and the buoyancy dominated regimes. The two heat sources are found to be essentially independent of each other, in terms of thermal effects, at a separation distance of more than about three strip widths for both the orientations. The results obtained are relevant to many engineering applications, such as the cooling of electronic systems, positioning of heating elements in furnaces, and safety considerations in enclosure fires.

  7. Prandtl Number Dependent Natural Convection with Internal Heat Sources

    SciTech Connect (OSTI)

    Kang Hee Lee; Seung Dong Lee; Kune Y. Suh; Joy L. Rempe; Fan-Bill Cheung; Sang B. Kim

    2004-06-01

    Natural convection plays an important role in determining the thermal load from debris accumulated in the reactor vessel lower head during a severe accident. Recently, attention is being paid to the feasibility of external vessel flooding as a severe accident management strategy and to the phenomena affecting the success path for retaining the molten core material inside the vessel. The heat transfer inside the molten core material can be characterized by the strong buoyancy-induced flows resulting from internal heating due to decay of fission products. The thermo-fluid dynamic characteristics of such flow depend strongly on the thermal boundary conditions. The spatial and temporal variation of heat flux on the pool wall boundaries and the pool superheat are mainly characterized by the natural convection flow inside the molten pool. In general, the natural convection heat transfer phenomena involving the internal heat generation are represented by the modified Rayleigh number (Ra’), which quantifies the internal heat source and hence the strength of the buoyancy force. In this study, tests were conducted in a rectangular section 250 mm high, 500 mm long and 160 mm wide. Twenty-four T-type thermocouples were installed in the test section to measure temperatures. Four T-type thermocouples were used to measure the boundary temperatures. The thermocouples were placed in designated locations after calibration. A direct heating method was adopted in this test to simulate the uniform heat generation. The experiments covered a range of Ra' between 1.5x106 and 7.42x1015 and the Prandtl number (Pr) between 0.7 and 6.5. Tests were conducted with water and air as simulant. The upper and lower boundary conditions were maintained uniform. The results demonstrated feasibility of the direct heating method to simulate uniform volumetric heat generation. Particular attentions were paid to the effect of Pr on natural convection heat transfer within the rectangular pool.

  8. Convective heat transfer inside passive solar buildings

    SciTech Connect (OSTI)

    Jones, R.W.; Balcomb, J.D.; Yamaguchi, K.

    1983-11-01

    Natural convection between spaces in a building which play a major role in energy transfer are discussed. Two situations are investigated: Convection through a single doorway into a remote room, and a convective loop in a two story house with a south sunspace where a north stairway serves as the return path. A doorway sizing equation is given for the single door case. Data from airflow monitoring in one two-story house and summary data for five others are presented. The nature of the airflow and design guidelines are presented.

  9. Convective heat transfer inside passive solar buildings

    SciTech Connect (OSTI)

    Jones, R.W.; Balcomb, J.D.; Yamaguchi, K.

    1983-01-01

    Natural convection between spaces in a building can play a major role in energy transfer. Two situations are investigated: convection through a single doorway into a remote room, and a convective loop in a two-story house with a south sunspace where a north stairway serves as the return path. A doorway-sizing equation is given for the single-door case. Detailed data are given from the monitoring of airflow in one two-story house and summary data are given for five others. Observations on the nature of the airflow and design guidelines are presented.

  10. Transient Mixed Convection Validation for NGNP

    SciTech Connect (OSTI)

    Smith, Barton; Schultz, Richard

    2015-10-19

    The results of this project are best described by the papers and dissertations that resulted from the work. They are included in their entirety in this document. They are: (1) Jeff Harris PhD dissertation (focused mainly on forced convection); (2) Blake Lance PhD dissertation (focused mainly on mixed and transient convection). This dissertation is in multi-paper format and includes the article currently submitted and one to be submitted shortly; and, (3) JFE paper on CFD Validation Benchmark for Forced Convection.

  11. Convective Cooling and Passive Stack Improvements in Motors (Presentation)

    SciTech Connect (OSTI)

    Bennion, K.

    2014-06-01

    This presentation discusses current research at NREL in convective cooling and passive stack improvements in motors.

  12. Vortex Tubes of Turbulent Solar Convection

    E-Print Network [OSTI]

    Kitiashvili, I N; Mansour, N N; Lele, S K; Wray, A A

    2011-01-01

    Investigation of turbulent properties of solar convection is extremely important for understanding of the multi-scale dynamics observed on the solar surface. In particular, recent high-resolution observations revealed ubiquitous vortical structures, and numerical simulations demonstrated links between the vortex tube dynamics and magnetic field organization, and also importance of vortex tube interactions in the mechanism of acoustic wave excitation on the Sun. In this paper we investigate mechanisms of formation of vortex tubes in highly-turbulent convective flows near the solar surface by using realistic radiative hydrodynamic LES simulations. Analysis of data, obtained by the simulations, indicates two basic processes of the vortex tube formation: 1) development of small-scale convective instability inside convective granules, and 2) a Kelvin-Helmholtz type instability of shearing flows in intergranular lanes. Our analysis shows that vortex stretching during these processes is a primary source of generatio...

  13. A modified convective/stratiform partitioning algorithm 

    E-Print Network [OSTI]

    Listemaa, Steven Alan

    1998-01-01

    by using different radar reflectivity-rail-ate relationships. Several authors have developed their own convective-stratiform partitioning, but each had its limitations. An algorithm has been developed which partitions precipitating systems...

  14. Circulation and convection in the Irminger Sea

    E-Print Network [OSTI]

    Våge, Kjetil

    2010-01-01

    Aspects of the circulation and convection in the Irminger Sea are investigated using a variety of in-situ, satellite, and atmospheric reanalysis products. Westerly Greenland tip jet events are intense, small-scale wind ...

  15. Stochastic and mesoscopic models for tropical convection

    E-Print Network [OSTI]

    Majda, Andrew J.

    Courant Institute of Mathematical Sciences and Center for Atmosphere and Ocean Sciences, New York penetrative convection to heights of 5­10 km with associated anvil towers of clouds. Observational data

  16. Modeling convection in the Greenland Sea

    E-Print Network [OSTI]

    Bhushan, Vikas

    1998-01-01

    A detailed examination of the development of a deep convection event observed in the Greenland Sea in 1988-89 is carried out through a combination of modeling, scale estimates, and data analysis. We develop a prognostic ...

  17. Convective cores in galactic cooling flows

    E-Print Network [OSTI]

    A. Kritsuk; T. Plewa; E. Mueller

    2001-05-02

    We use hydrodynamic simulations with adaptive grid refinement to study the dependence of hot gas flows in X-ray luminous giant elliptical galaxies on the efficiency of heat supply to the gas. We consider a number of potential heating mechanisms including Type Ia supernovae and sporadic nuclear activity of a central supermassive black hole. As a starting point for this research we use an equilibrium hydrostatic recycling model (Kritsuk 1996). We show that a compact cooling inflow develops, if the heating is slightly insufficient to counterbalance radiative cooling of the hot gas in the central few kiloparsecs. An excessive heating in the centre, instead, drives a convectively unstable outflow. We model the onset of the instability and a quasi-steady convective regime in the core of the galaxy in two-dimensions assuming axial symmetry. Provided the power of net energy supply in the core is not too high, the convection remains subsonic. The convective pattern is dominated by buoyancy driven large-scale mushroom-like structures. Unlike in the case of a cooling inflow, the X-ray surface brightness of an (on average) isentropic convective core does not display a sharp maximum at the centre. A hybrid model, which combines a subsonic peripheral cooling inflow with an inner convective core, appears to be stable. We also discuss observational implications of these results.

  18. Exploring the LandOcean Contrast in Convective Vigor Using Islands F. J. ROBINSON

    E-Print Network [OSTI]

    Sherwood, Steven

    was idealized, with islands represented by regions of uniform surface heat flux without orography, using a rangeExploring the Land­Ocean Contrast in Convective Vigor Using Islands F. J. ROBINSON Department) observations over islands of increasing size to those simulated by a cloud- resolving model. The observed

  19. Natural versus forced convection in laminar starting plumes Michael C. Rogers and Stephen W. Morris

    E-Print Network [OSTI]

    Morris, Stephen W.

    fluid from a small, submerged outlet. The plumes were laminar and spanned a wide range of plume, the most important fac- tor determining jet or plume behaviour and evolution is whether the flow is laminar orNatural versus forced convection in laminar starting plumes Michael C. Rogers and Stephen W. Morris

  20. Study of natural convection heat transfer above a horizontal heated plate using a laser specklegram technique 

    E-Print Network [OSTI]

    Cheeti, Satish K.R.

    1993-01-01

    and the average heat transfer coefficients and hence the Nusselt numbers were determined in the range of Rayleigh numbers from 9 x 10' to 4 x 10'. The nature of the free convection flow over the heated surface was inferred from the local and average Nusselt...

  1. Measure the uv profiles along the actual oven location, and evaluate the uv fluence over an area comparable to c/p.

    E-Print Network [OSTI]

    Goal: Measure the uv profiles along the actual oven location, and evaluate the uv fluence over to be measured and optimized if there is any clipping of the uv beam. - The local fluence needs to be measuredNe laser beam onto which the uv has been aligned "by eye", as in the real experiment, 2) an image of the uv

  2. Critical heat flux for free convection boiling in thin rectangular channels

    SciTech Connect (OSTI)

    Cheng, Lap Y.; Tichler, P.R.

    1991-01-01

    A review of the experimental data on free convection boiling critical heat flux (CHF) in vertical rectangular channels reveals three mechanisms of burnout. They are the pool boiling limit, the circulation limit, and the flooding limit associated with a transition in flow regime from churn to annular flow. The dominance of a particular mechanism depends on the dimensions of the channel. Analytical models were developed for each free convection boiling limit. Limited agreement with data is observed. A CHF correlation, which is valid for a wide range of gap sizes, was constructed from the CHFs calculated according to the three mechanisms of burnout. 17 refs., 7 figs.

  3. M. Bahrami ENSC 388 (F09) Forced Convection Heat Transfer 1 Forced Convection Heat Transfer

    E-Print Network [OSTI]

    Bahrami, Majid

    surface, and the type of the fluid flow (laminar or turbulent). Fig. 1: Forced convection fluid. Whereas in forced convection, the fluid is forced to flow over a surface or in a tube Boundary Layer Consider the flow of a fluid over a flat plate, the velocity and the temperature

  4. Standing Accretion Shocks in the Supernova Core: Effects of Convection and Realistic EOS

    E-Print Network [OSTI]

    Tatsuya Yamasaki; Shoichi Yamada

    2006-08-25

    We investigated the structure of the spherically symmetric accretion flows through the standing shock wave onto the proto-neutron star in the post-bounce phase of the collapse-driven supernova. We assume that the accretion flow is in a steady state controlled by the neutrino luminosity and mass accretion rate that are kept constant. We obtain solutions of the steady Euler equations for a wide range of neutrino luminosity and mass accretion rate. We employ a realistic EOS and neutrino-heating rates. More importantly, we take into account the effect of convection phenomenologically. For each mass accretion rate, we find the critical neutrino luminosity, above which there exists no steady solution. These critical points are supposed to mark the onset of the shock revival. As the neutrino luminosity increases for a given mass accretion rate, there appears a convectively unstable region at some point before the critical value is reached. We introduce a phenomenological energy flux by convection so that the negative entropy gradient should be canceled out. We find that the convection lowers the critical neutrino luminosity substantially. We also consider the effect of the self-gravity. It is found that the self-gravity is important only when the neutrino luminosity is high. The critical luminosity, however, is little affected if the energy transport by convection is taken into account.

  5. Low enthalpy convective system in Western Ohio

    SciTech Connect (OSTI)

    Cannon, M.S.; Tabet, C.A.; Eckstein, Y.

    1980-01-01

    A distinct positive anomaly in the temperatures of the shallow (Pleistocene) aquifers along the Cincinnati-Findlay Arch in Western Ohio coincides with a low geothermal gradient. A conceptual model of convective currents associated with a tensional fault and/or fracture system along the crest of the Arch is suggested as an explanation of the anomaly. Hydrochemical information indicates that various quantities of warmer ground water, with the composition characteristics of deep bedrock aquifers, is present as an admixture in the shallow aquifers. This confirms the conceptual model of convection in fractures.

  6. Laser induced ponderomotive convection in water

    E-Print Network [OSTI]

    Shneider, M N

    2015-01-01

    A new mechanism for inducing convection during IR laser interaction with water or any absorbing polar liquid is described theoretically. The numerical simulations performed using the developed model show that the ponderomotive force produces water flow in the direction of the laser beam propagation. In the later stage of interaction, when water temperature rises, the Archimedes force becomes first comparable and then dominant producing convection directed against the vector of gravitational acceleration (upward). The theoretical estimates and the numerical simulations predict fluid dynamics that is similar to the observed in the previous experiments.

  7. Geothermal reservoirs in hydrothermal convection systems

    SciTech Connect (OSTI)

    Sorey, M.L.

    1982-01-01

    Geothermal reservoirs commonly exist in hydrothermal convection systems involving fluid circulation downward in areas of recharge and upwards in areas of discharge. Because such reservoirs are not isolated from their surroundings, the nature of thermal and hydrologic connections with the rest of the system may have significant effects on the natural state of the reservoir and on its response to development. Conditions observed at numerous developed and undeveloped geothermal fields are discussed with respect to a basic model of the discharge portion of an active hydrothermal convection system. Effects of reservoir development on surficial discharge of thermal fluid are also delineated.

  8. Thermal convection in a liquid metal battery

    E-Print Network [OSTI]

    Shen, Yuxin

    2015-01-01

    Generation of thermal convection flow in the liquid metal battery, a device recently proposed as a promising solution for the problem of the short-term energy storage, is analyzed using a numerical model. It is found that convection caused by Joule heating of electrolyte during charging or discharging is virtually unavoidable. It exists in laboratory prototypes larger than a few cm in size and should become much stronger in larger-scale batteries. The phenomenon needs further investigation in view of its positive (enhanced mixing of reactants) and negative (loss of efficiency and possible disruption of operation due to the flow-induced deformation of the electrolyte layer) effects.

  9. Generation and Trapping of Gravity Waves from Convection with Comparison to Parameterization

    E-Print Network [OSTI]

    Alexander, M. Joan

    Generation and Trapping of Gravity Waves from Convection with Comparison to Parameterization M (GCMs) add realism by describing wave generation by tropospheric convection. Because the convection in GCMs is itself a parameterized process, these convectively generated wave parameterizations necessarily

  10. Numerical models of Rayleigh-Taylor instabilities superimposed upon convection

    E-Print Network [OSTI]

    Schmeling, Harro

    one R.T.-overturn to multiple convective with salt tectonics (R.T.), plutonism (R.T.), plate overturns. Secondly, how is the temperature field tectonics and mantle flows (convection) (see e.g. affected

  11. Layer inflow into precipitating convection over the western tropical Pacific

    E-Print Network [OSTI]

    Mechem, David B.; Houze, Robert A. Jr.; Chen, Shuyi S.

    2002-07-01

    A conceptual model of tropical convection frequently used in convective parametrization schemes is that of a parcel process in which boundary-layer air, characterized by high equivalent potential temperature, ascends to ...

  12. On the Forecasting of Orogenic Mesoscale Convective Complexes

    E-Print Network [OSTI]

    Tucker, Donna F.; Zentmire, Kristine S.

    1999-12-01

    ., 1980: Mesoscale convective complexes. Bull. Amer. Meteor. Soc., 61, 1374–1387. , 1983: Large-scale meteorological conditions associated with midlatitude mesoscale convective complexes. Mon. Wea. Rev., 111, 1475–1493. , D. M. Rodgers, and K. W. Howard..., 1982: Mesoscale convective complexes over the United States during 1981—Annual sum- mary. Mon. Wea. Rev., 110, 1501–1514. , K. W. Howard, D. L. Bartels, and D. M. Rodgers, 1986: Me- soscale convective complexes in the middle latitudes. Mesoscale...

  13. Deep convective parameterization: Some issues (and some solutions?)

    E-Print Network [OSTI]

    Plant, Robert

    are basically an exercise in engineering / tuning fairly bad Deep convective parameterization ­ p.1/4 #12;Aim in engineering / tuning fairly bad The reality is that deep convective parameterizations are basicallyDeep convective parameterization: Some issues (and some solutions?) Bob Plant Department

  14. Convection in Stars Proceedings IAU Symposium No. 239, 2007

    E-Print Network [OSTI]

    Arnett, W. David

    and the geometric parameters in mixing length theory, and the solar Ne abundance problem. Explicit comparisons convection (with nuclear burning). The simulations are run long enough so that a robust statistical state will be made with convective driving of waves, convective zone growth by entrainment, the velocity scale

  15. Convective injection into stratospheric intrusions Cameron R. Homeyer,1

    E-Print Network [OSTI]

    Pan, Laura

    Convective injection into stratospheric intrusions Cameron R. Homeyer,1 Kenneth P. Bowman,1 Laura L, are not entirely understood. This study presents direct observations of moist convection penetrating into stratospheric intrusions. The characteristics of convective injection are shown by using in situ aircraft

  16. The convective structures associated with cloud-to-ground lightning in TOGA COARE Mesoscale Convective Systems 

    E-Print Network [OSTI]

    Restivo, Michael Edward

    1995-01-01

    The TOGA COARE experiment was carried out in the western Pacific warm pool region from November 1992 through February 1993. Data from TOGA COARE provide the opportunity for comprehensive studies of tropical oceanic convection. ...

  17. Laminar boundary layers in convective heat transport

    E-Print Network [OSTI]

    Christian Seis

    2012-12-12

    We study Rayleigh-Benard convection in the high-Rayleigh-number and high-Prandtl-number regime, i.e., we consider a fluid in a container that is exposed to strong heating of the bottom and cooling of the top plate in the absence of inertia effects. While the dynamics in the bulk are characterized by a chaotic convective heat flow, the boundary layers at the horizontal container plates are essentially conducting and thus the fluid is motionless. Consequently, the average temperature exhibits a linear profile in the boundary layers. In this article, we rigorously investigate the average temperature and oscillations in the boundary layer via local bounds on the temperature field. Moreover, we deduce that the temperature profile is indeed essentially linear close to the horizontal container plates. Our results are uniform in the system parameters (e.g. the Rayleigh number) up to logarithmic correction terms. An important tool in our analysis is a new Hardy-type estimate for the convecting velocity field, which can be used to control the fluid motion in the layer. The bounds on the temperature field are derived with the help of local maximal regularity estimates for convection-diffusion equations.

  18. Vertical profiles of radar reflectivity of convective cells in tropical and mid-latitude mesoscale convective systems 

    E-Print Network [OSTI]

    Lutz, Kurt Reed

    1992-01-01

    VERTICAL PROFILES OF RADAR REFLECTIVITY OF CONVECTIVE CELLS IN TROPICAL AND MID-LATITUDE MESOSCALE CONVECTIVE SYSTEMS A Thesis by KURT REED LUTZ Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE December 1992 Major Subject: Meteorology VERTICAL PROFILES OF RADAR REFLECTIVITY OF CONVECTIVE CELLS IN TROPICAL AND MID-LATITUDE MESOSCALE CONVECTIVE SYSTEMS A Thesis by KURT REED LUTZ Approved...

  19. Urinary 1-hydroxypyrene concentrations in Chinese coke oven workers relative to job category, respirator usage, and cigarette smoking

    SciTech Connect (OSTI)

    Bo Chen; Yunping Hu; Lixing Zheng; Qiangyi Wang; Yuanfen Zhou; Taiyi Jin [Fudan University, Shanghai (China). School of Public Health

    2007-09-15

    1-Hydroxypyrene (1-OHP) is a biomarker of recent exposure to polycyclic aromatic hydrocarbons (PAHs). We investigated whether urinary 1-OHP concentrations in Chinese coke oven workers (COWs) are modulated by job category, respirator usage, and cigarette smoking. The present cross-sectional study measured urinary 1-OHP concentrations in 197 COWs from Coking plant I and 250 COWs from Coking plant II, as well as 220 unexposed referents from Control plant I and 56 referents from Control plant II. Urinary 1-OHP concentrations (geometric mean, {mu}mol/mol creatinine) were 5.18 and 4.21 in workers from Coking plants I and II, respectively. The highest 1-OHP levels in urine were found among topside workers including lidmen, tar chasers, and whistlers. Benchmen had higher 1-OHP levels than other workers at the sideoven. Above 75% of the COWs exceeded the recommended occupational exposure limit of 2.3 {mu}mol/mol creatinine. Respirator usage and increased body mass index (BMI) slightly reduced 1-OHP levels in COWs. Cigarette smoking significantly increased urinary 1-OHP levels in unexposed referents but had no effect in COWs. Chinese COWs, especially topside workers and benchmen, are exposed to high levels of PAHs. Urinary 1-OHP concentrations appear to be modulated by respirator usage and BMI in COWs, as well as by smoking in unexposed referents.

  20. Coke oven air and water pollution. 1970-June, 1981 (citations from the Engineering Index Data Base). Report for 1970-Jun 81

    SciTech Connect (OSTI)

    Not Available

    1981-07-01

    Monitoring, sampling, analyzing, transport properties, and control of emissions and effluents are cited in this compilation from worldwide journals. Pollutants described are sulfur dioxide, hydrogen sulfide, ammonia, phenols, benzopyrene, particulates and other trace elements and compounds. Process and equipment modifications, such as pipeline charging, wet and dry quenching, retrofitting, and oven leakage preventives are included. (This updated bibliography contains 210 citations, 9 of which are new entries to the previous edition.)

  1. Wind reversals in turbulent Rayleigh-Benard convection

    E-Print Network [OSTI]

    Francisco Fontenele Araujo; S. Grossmann; D. Lohse

    2005-08-29

    The phenomenon of irregular cessation and subsequent reversal of the large-scale circulation in turbulent Rayleigh-B\\'enard convection is theoretically analysed. The force and thermal balance on a single plume detached from the thermal boundary layer yields a set of coupled nonlinear equations, whose dynamics is related to the Lorenz equations. For Prandtl and Rayleigh numbers in the range $10^{-2} \\leq \\Pr \\leq 10^{3}$ and $10^{7} \\leq \\Ra \\leq 10^{12}$, the model has the following features: (i) chaotic reversals may be exhibited at Ra $\\geq 10^{7}$; (ii) the Reynolds number based on the root mean square velocity scales as $\\Re_{rms} \\sim \\Ra^{[0.41 ... 0.47]}$ (depending on Pr), and as $\\Re_{rms} \\sim \\Pr^{-[0.66 ... 0.76]}$ (depending on Ra); and (iii) the mean reversal frequency follows an effective scaling law $\\omega / (\

  2. Penetrative internally heated convection in two and three dimensions

    E-Print Network [OSTI]

    Goluskin, David

    2015-01-01

    Convection of an internally heated fluid, confined between top and bottom plates of equal temperature, is studied by direct numerical simulation in two and three dimensions. The unstably stratified upper region drives convection that penetrates into the stably stratified lower region. The fraction of produced heat escaping across the bottom plate, which is one half without convection, initially decreases as convection strengthens. Entering the turbulent regime, this decrease reverses in two dimensions but continues monotonically in three dimensions. The mean fluid temperature, which grows proportionally to the heating rate ($H$) without convection, grows like $H^{4/5}$ when convection is strong in both two and three dimensions. The ratio of the heating rate to the fluid temperature is likened to the Nusselt number of Rayleigh-B\\'enard convection. Simulations are reported for Prandtl numbers between 0.1 and 10 and for Rayleigh numbers (defined in terms of the heating rate) up to $5\\times10^{10}$.

  3. Technical support document: Energy efficiency standards for consumer products: Room air conditioners, water heaters, direct heating equipment, mobile home furnaces, kitchen ranges and ovens, pool heaters, fluorescent lamp ballasts and television sets. Volume 2, Fluorescent lamp ballasts, television sets, room air conditioners, and kitchen ranges and ovens

    SciTech Connect (OSTI)

    Not Available

    1993-11-01

    This document is divided into ``volumes`` B through E, dealing with individual classes of consumer products. Chapters in each present engineering analysis, base case forecasts, projected national impacts of standards, life-cycle costs and payback periods, impacts on manufacturers, impacts of standards on electric utilities, and environmental effects. Supporting appendices are included.

  4. Convection of a stratified colloidal suspension

    SciTech Connect (OSTI)

    Cherepanov, I. N.; Smorodin, B. L., E-mail: bsmorodin@yandex.ru [Perm National Research University (Russian Federation)

    2013-11-15

    The convection of a colloidal suspension, which is a binary mixture of a carrier medium with an admixture of nanoparticles having a large positive thermal diffusion parameter, has been studied for the case of the heating of a horizontal cell from below and periodic conditions at the vertical boundaries corresponding to the experimental situation of ring channels. Bifurcation diagrams have been constructed for vibrational and monotonic regimes of the convection of the colloidal mixture. The time dependences of the maximum stream function and the stream function at a fixed point of the cell, as well as the spatial distributions of the concentration field of the colloid admixture, have been obtained. It has been shown that a stable regime of traveling waves exists in a certain region of the parameters of the problem (Boltzmann and Rayleigh numbers characterizing the gravitational stratification and intensity of the thermal effect, respectively)

  5. Convective heat transport in compressible fluids Akira Furukawa and Akira Onuki

    E-Print Network [OSTI]

    is equal to 0.034 mK/cm for 3 He and 0.27 mK/cm for CO2. This is the condition that the entropy s s of convection experiments in compressible one-component fluids in the supercritical re- gion 9­19 , together Pr / D was in the range of 1­100. High compressibility of supercritical fluids gives rise to some

  6. RANGE-ENERGY TABLES

    E-Print Network [OSTI]

    Rich, Marvin

    2010-01-01

    Particles. II. PROTON RANGE-ENERGY DATA Stopping Medium: Be2301 III. PION RANGE-ENERGY DATA Mev. Pion Kinetic Energy2301 IV. DEUTERON RANGE-ENERGY DATA Deuteron Kinetic Energy

  7. Laminar boundary layers in convective heat transport

    E-Print Network [OSTI]

    Seis, Christian

    2012-01-01

    We study Rayleigh-Benard convection in the high-Rayleigh-number and high-Prandtl-number regime, i.e., we consider a fluid in a container that is exposed to strong heating of the bottom and cooling of the top plate in the absence of inertia effects. While the dynamics in the bulk are characterized by a chaotic convective heat flow, the boundary layers at the horizontal container plates are essentially conducting and thus the fluid is motionless. Consequently, the average temperature exhibits a linear profile in the boundary layers. In this article, we rigorously investigate the average temperature and oscillations in the boundary layer via local bounds on the temperature field. Moreover, we deduce that the temperature profile is indeed essentially linear close to the horizontal container plates. Our results are uniform in the system parameters (e.g. the Rayleigh number) up to logarithmic correction terms. An important tool in our analysis is a new Hardy-type estimate for the convecting velocity field, which ca...

  8. Convective heat transport in geothermal systems

    SciTech Connect (OSTI)

    Lippmann, M.J.; Bodvarsson, G.S.

    1986-08-01

    Most geothermal systems under exploitation for direct use or electrical power production are of the hydrothermal type, where heat is transferred essentially by convection in the reservoir, conduction being secondary. In geothermal systems, buoyancy effects are generally important, but often the fluid and heat flow patterns are largely controlled by geologic features (e.g., faults, fractures, continuity of layers) and location of recharge and discharge zones. During exploitation, these flow patterns can drastically change in response to pressure and temperature declines, and changes in recharge/discharge patterns. Convective circulation models of several geothermal systems, before and after start of fluid production, are described, with emphasis on different characteristics of the systems and the effects of exploitation on their evolution. Convective heat transport in geothermal fields is discussed, taking into consideration (1) major geologic features; (2) temperature-dependent rock and fluid properties; (3) fracture- versus porous-medium characteristics; (4) single- versus two-phase reservoir systems; and (5) the presence of noncondensible gases.

  9. Convective Dynamo Simulation with a Grand Minimum

    E-Print Network [OSTI]

    Augustson, Kyle; Miesch, Mark; Toomre, Juri

    2015-01-01

    The global-scale dynamo action achieved in a simulation of a Sun-like star rotating at thrice the solar rate is assessed. The 3-D MHD Anelastic Spherical Harmonic (ASH) code, augmented with a viscosity minimization scheme, is employed to capture convection and dynamo processes in this G-type star. The simulation is carried out in a spherical shell that encompasses 3.8 density scale heights of the solar convection zone. It is found that dynamo action with a high degree of time variation occurs, with many periodic polarity reversals occurring roughly every 6.2 years. The magnetic energy also rises and falls with a regular period. The magnetic energy cycles arise from a Lorentz-force feedback on the differential rotation, whereas the processes leading to polarity reversals are more complex, appearing to arise from the interaction of convection with the mean toroidal fields. Moreover, an equatorial migration of toroidal field is found, which is linked to the changing differential rotation, and potentially to a no...

  10. Moist Convection and the Thermal Stratification of the Extratropical Troposphere TAPIO SCHNEIDER AND PAUL A. O'GORMAN

    E-Print Network [OSTI]

    O'Gorman, Paul

    Moist Convection and the Thermal Stratification of the Extratropical Troposphere TAPIO SCHNEIDER thermal stratification over a wide range of climates, even in relatively warm climates with small only marginally affects the extratropical thermal stratification in Earth-like and colder climates

  11. Effects of convection on the mean solar structure

    E-Print Network [OSTI]

    Christensen-Dalsgaard, J

    1996-01-01

    The overall framework for the study of solar convection and oscillations is the spherically symmetric component of solar structure. I discuss those properties of the solar interior which depend on convection and other possible hydrodynamical motion and the increasingly detailed information about the structure which is provided by helioseismic data. The most basic dependence of solar models on convection is the calibration to fix the solar radius. The dominant causes for differences in oscillation frequencies between the Sun and solar models seem to be located near the top of the convection zone. However, there is also evidence for possible weak mixing below the convection zone and perhaps in the solar core. The former, at least, might be induced by penetration of convective motion into the stable layers below.

  12. Lesson 9 - Solar Ovens

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousand CubicResourcelogo and-E C H N I CLenslessLeslie Pochbiomass

  13. Soil Moisture Impacts on Convective Precipitation in Oklahoma 

    E-Print Network [OSTI]

    Ford, Trenton

    2015-07-24

    of the States” instilled in me a lifelong curiosity in Geography. v NOMENCLATURE CAPE Convective Available Potential Energy CIN Convective Inhibition CTP Convective Triggering Potential DDR Directional Difference Ratio DM Dry Moderate DP Dry Polar.... The black line represents the 1-to-1 fit, while the dashed line represents the least squares fit. .………………………..119 Figure 5.3. Boxplots of DDR from each directional difference over dry soil events. The black, dashed line represents the 0 value, by which...

  14. Interactions between cumulus convection and its environment as...

    Office of Scientific and Technical Information (OSTI)

    Convective Clouds Experiment (MC3E) in central Oklahoma. Distinct large-scale structures and diabatic heating and drying profiles are presented for cases of weaker and...

  15. Objectives of Work Packages WP1: Thermal convection

    E-Print Network [OSTI]

    Cerveny, Vlastislav

    MAGMA Objectives of Work Packages WP1: Thermal convection Coordinator: O. Cadek · To enhance air-pollution assessment in the urban environment · To study the solar radiation impact

  16. NATURAL CONVECTION IN PASSIVE SOLAR BUILDINGS: EXPERIMENTS, ANALYSIS AND RESULTS

    E-Print Network [OSTI]

    Gadgil, Ashok; Bauman, Fred; Kammerud, Ronald

    2008-01-01

    CONVECTION IN PASSIVE SOLAR BUILDINGS: ANALYSIS AND RESULTSCONVECTION IN PASSIVE SOLAR BUILDINGS: EXPERIMENTS, ANALYSISin a direct gain passive solar building; this is described

  17. Convectively generated zonal jets by thunderstorms on Jupiter

    E-Print Network [OSTI]

    Zhang, Xi Arthur; Showman, Adam

    2011-01-01

    formation of equatorial jets in freely decaying shallowof moist convection with zonal jets on Jupiter and Saturn,Generation of equatorial jets by large-scale latent heating

  18. Natural convection airflow measurement and theory

    SciTech Connect (OSTI)

    Balcomb, J.D.; Jones, G.F.; Yamaguchi, Kenjiro

    1984-01-01

    Natural convection is a major mechanism for heat distribution in many passive solar buildings, especially those with sunspaces. To better understand this mechanism, observations of air velocities and temperatures have been made in 13 different houses that encompass a wide variety of one- and two-story geometries. This paper extends previous reports. Results from one house are described in detail, and some generalizations are drawn from the large additional mass of data taken. A simple mathematical model is presented that describes the general nature of airflow and energy flow through an aperture.

  19. Atmospheric Radiation Measurement Convective and Orographically Induced

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O O DBiomass and BiofuelsPhysicist47 Industrial1Convective and

  20. ARM - Evaluation Product - Convective Vertical Velocity

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Comments? WeDatastreamstps DocumentationAtlanticENA Contacts ENA RelatedProductsCalibrated KAZRProductsConvective

  1. Air convection noise of pencil-beam interferometer for long trace profiler

    E-Print Network [OSTI]

    Yashchuk, Valeriy V.; Irick, Steve C.; MacDowell, Alastair A.; McKinney, Wayne R.; Takacs, Peter Z.

    2006-01-01

    Air Convection Noise of Pencil-beam Interferometer for Longwe investigate the effect of air convection on laser-beamshown that the NPD spectra due to air convection have a very

  2. Observational Analysis of the Predictability of Mesoscale Convective Systems ISRAEL L. JIRAK AND WILLIAM R. COTTON

    E-Print Network [OSTI]

    Observational Analysis of the Predictability of Mesoscale Convective Systems ISRAEL L. JIRAK (Manuscript received 30 December 2005, in final form 4 October 2006) ABSTRACT Mesoscale convective systems of usefulness in operational forecasting. 1. Introduction Mesoscale convective systems (MCSs) frequently de

  3. CONVECTIVE STABILITY OF GALAXY-CLUSTER PLASMAS Benjamin D. Chandran

    E-Print Network [OSTI]

    Chandran, Ben

    criterion by causing heat to diffuse primarily along magnetic field lines. We extend earlier analyses a cluster's age. In the cooling flow model, plasma heating is neglected, and the rate at which plasma cools nuclei and cosmic rays drive convection in galaxy-cluster plasmas and that convection heats cluster cores

  4. MPO 663 -Convective and Mesoscale Meteorology Brian Mapes, Spring 2008

    E-Print Network [OSTI]

    Miami, University of

    MPO 663 - Convective and Mesoscale Meteorology Brian Mapes, Spring 2008 I intend for students and mesoscale phenomena. 2. Working understanding of several of these tools, cultivated via homework, including. A sense of how convective and mesoscale phenomena fit into larger scales, gained via short current

  5. ON THE INTERACTION BETWEEN CONVECTION AND MAGNETIC FIELDS Fausto Cattaneo

    E-Print Network [OSTI]

    Emonet, Thierry

    found in these different regimes are described and analyzed. Subject headings: convection -- Sun: magnetic fields -- Sun: photosphere 1. INTRODUCTION Magnetic activity is exhibited by late-type stars with deep convective envelopes, but the fine structure of the magnetic field can only be detected on the Sun

  6. Accepted Manuscript Simulations of stellar convection with CO5BOLD

    E-Print Network [OSTI]

    Wedemeyer-Böhm, Sven

    ­ the top of the deep-reaching solar convection zone. Convection plays a role for the thermal structure of the solar interior and the dynamo acting there, for the stratification of the photosphere, where most stratification leads to completely dif- ferent conditions in the interior, the photosphere, and the corona

  7. Characterizing the convective velocity fields in massive stars

    SciTech Connect (OSTI)

    Chatzopoulos, Emmanouil; Graziani, Carlo; Couch, Sean M., E-mail: manolis@astro.as.utexas.edu [Department of Astronomy and Astrophysics, Flash Center for Computational Science, University of Chicago, Chicago, IL 60637 (United States)

    2014-11-01

    We apply the mathematical formalism of vector spherical harmonics decomposition to convective stellar velocity fields from multidimensional hydrodynamics simulations and show that the resulting power spectra furnish a robust and stable statistical description of stellar convective turbulence. Analysis of the power spectra helps identify key physical parameters of the convective process such as the dominant scale of the turbulent motions that influence the structure of massive evolved pre-supernova stars. We introduce the numerical method that can be used to calculate vector spherical harmonics power spectra from two-dimensional (2D) and three-dimensional (3D) convective shell simulation data. Using this method we study the properties of oxygen shell burning and convection for a 15 M {sub ?} star simulated by the hydrodynamics code FLASH in 2D and 3D. We discuss the importance of realistic initial conditions to achieving successful core-collapse supernova explosions in multidimensional simulations. We show that the calculated power spectra can be used to generate realizations of the velocity fields of presupernova convective shells. We find that the slope of the solenoidal mode power spectrum remains mostly constant throughout the evolution of convection in the oxygen shell in both 2D and 3D simulations. We also find that the characteristic radial scales of the convective elements are smaller in 3D than in 2D, while the angular scales are larger in 3D.

  8. Plains Elevated Convection at Night (PECAN) Experiment Science Plan

    SciTech Connect (OSTI)

    Turner, D; Parsons, D; Geerts, B

    2015-03-01

    The Plains Elevated Convection at Night (PECAN) experiment is a large field campaign that is being supported by the National Science Foundation (NSF) with contributions from the National Oceanic and Atmospheric Administration (NOAA), the National Atmospheric and Space Administration (NASA), and the U.S. Department of Energy (DOE). The overarching goal of the PECAN experiment is to improve the understanding and simulation of the processes that initiate and maintain convection and convective precipitation at night over the central portion of the Great Plains region of the United States (Parsons et al. 2013). These goals are important because (1) a large fraction of the yearly precipitation in the Great Plains comes from nocturnal convection, (2) nocturnal convection in the Great Plains is most often decoupled from the ground and, thus, is forced by other phenomena aloft (e.g., propagating bores, frontal boundaries, low-level jets [LLJ], etc.), (3) there is a relative lack of understanding how these disturbances initiate and maintain nocturnal convection, and (4) this lack of understanding greatly hampers the ability of numerical weather and climate models to simulate nocturnal convection well. This leads to significant uncertainties in predicting the onset, location, frequency, and intensity of convective cloud systems and associated weather hazards over the Great Plains.

  9. Influences of soil moisture and vegetation on convective precipitation forecasts

    E-Print Network [OSTI]

    Robock, Alan

    Influences of soil moisture and vegetation on convective precipitation forecasts over the United and vegetation on 30 h convective precipitation forecasts using the Weather Research and Forecasting model over, the complete removal of vegetation produced substantially less precipitation, while conversion to forest led

  10. Precipitation distributions for explicit versus parameterized convection in a

    E-Print Network [OSTI]

    Wirosoetisno, Djoko

    Precipitation distributions for explicit versus parameterized convection in a large-domain high.J. and Lister, G.M.S. (2012) Precipitation distributions for explicit versus parameterized convection in a large. Meteorol. Soc. 138: 1692­1708, October 2012 A Precipitation distributions for explicit versus parametrized

  11. Precipitation characteristics of CAM5 physics at mesoscale resolution during MC3E and the impact of convective timescale choice

    SciTech Connect (OSTI)

    Gustafson, William I.; Ma, Po-Lun; Singh, Balwinder

    2014-12-01

    The physics suite of the Community Atmosphere Model version 5 (CAM5) has recently been implemented in the Weather Research and Forecasting (WRF) model to explore the behavior of the parameterization suite at high resolution and in the more controlled setting of a limited area model. The initial paper documenting this capability characterized the behavior for northern high latitude conditions. This present paper characterizes the precipitation characteristics for continental, mid-latitude, springtime conditions during the Midlatitude Continental Convective Clouds Experiment (MC3E) over the central United States. This period exhibited a range of convective conditions from those driven strongly by large-scale synoptic regimes to more locally driven convection. The study focuses on the precipitation behavior at 32 km grid spacing to better anticipate how the physics will behave in the global model when used at similar grid spacing in the coming years. Importantly, one change to the Zhang-McFarlane deep convective parameterization when implemented in WRF was to make the convective timescale parameter an explicit function of grid spacing. This study examines the sensitivity of the precipitation to the default value of the convective timescale in WRF, which is 600 seconds for 32 km grid spacing, to the value of 3600 seconds used for 2 degree grid spacing in CAM5. For comparison, an infinite convective timescale is also used. The results show that the 600 second timescale gives the most accurate precipitation over the central United States in terms of rain amount. However, this setting has the worst precipitation diurnal cycle, with the convection too tightly linked to the daytime surface heating. Longer timescales greatly improve the diurnal cycle but result in less precipitation and produce a low bias. An analysis of rain rates shows the accurate precipitation amount with the shorter timescale is assembled from an over abundance of drizzle combined with too little heavy rain events. With longer timescales one can improve the distribution, particularly for the extreme rain rates. Ultimately, without changing other aspects of the physics, one must choose between accurate diurnal timing and rain amount when choosing an appropriate convective timescale.

  12. Precipitation characteristics of CAM5 physics at mesoscale resolution during MC3E and the impact of convective timescale choice

    SciTech Connect (OSTI)

    Gustafson, William I.; Ma, Po-Lun; Singh, Balwinder

    2014-12-17

    The physics suite of the Community Atmosphere Model version 5 (CAM5) has recently been implemented in the Weather Research and Forecasting (WRF) model to explore the behavior of the parameterization suite at high resolution and in the more controlled setting of a limited area model. The initial paper documenting this capability characterized the behavior for northern high latitude conditions. This present paper characterizes the precipitation characteristics for continental, mid-latitude, springtime conditions during the Midlatitude Continental Convective Clouds Experiment (MC3E) over the central United States. This period exhibited a range of convective conditions from those driven strongly by large-scale synoptic regimes to more locally driven convection. The study focuses on the precipitation behavior at 32 km grid spacing to better anticipate how the physics will behave in the global model when used at similar grid spacing in the coming years. Importantly, one change to the Zhang-McFarlane deep convective parameterization when implemented in WRF was to make the convective timescale parameter an explicit function of grid spacing. This study examines the sensitivity of the precipitation to the default value of the convective timescale in WRF, which is 600 seconds for 32 km grid spacing, to the value of 3600 seconds used for 2 degree grid spacing in CAM5. For comparison, an infinite convective timescale is also used. The results show that the 600 second timescale gives the most accurate precipitation over the central United States in terms of rain amount. However, this setting has the worst precipitation diurnal cycle, with the convection too tightly linked to the daytime surface heating. Longer timescales greatly improve the diurnal cycle but result in less precipitation and produce a low bias. An analysis of rain rates shows the accurate precipitation amount with the shorter timescale is assembled from an over abundance of drizzle combined with too little heavy rain events. With longer timescales one can improve the distribution, particularly for the extreme rain rates. Ultimately, without changing other aspects of the physics, one must choose between accurate diurnal timing and rain amount when choosing an appropriate convective timescale.

  13. Precipitation characteristics of CAM5 physics at mesoscale resolution during MC3E and the impact of convective timescale choice

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gustafson, William I.; Ma, Po-Lun; Singh, Balwinder

    2014-12-17

    The physics suite of the Community Atmosphere Model version 5 (CAM5) has recently been implemented in the Weather Research and Forecasting (WRF) model to explore the behavior of the parameterization suite at high resolution and in the more controlled setting of a limited area model. The initial paper documenting this capability characterized the behavior for northern high latitude conditions. This present paper characterizes the precipitation characteristics for continental, mid-latitude, springtime conditions during the Midlatitude Continental Convective Clouds Experiment (MC3E) over the central United States. This period exhibited a range of convective conditions from those driven strongly by large-scale synoptic regimesmore »to more locally driven convection. The study focuses on the precipitation behavior at 32 km grid spacing to better anticipate how the physics will behave in the global model when used at similar grid spacing in the coming years. Importantly, one change to the Zhang-McFarlane deep convective parameterization when implemented in WRF was to make the convective timescale parameter an explicit function of grid spacing. This study examines the sensitivity of the precipitation to the default value of the convective timescale in WRF, which is 600 seconds for 32 km grid spacing, to the value of 3600 seconds used for 2 degree grid spacing in CAM5. For comparison, an infinite convective timescale is also used. The results show that the 600 second timescale gives the most accurate precipitation over the central United States in terms of rain amount. However, this setting has the worst precipitation diurnal cycle, with the convection too tightly linked to the daytime surface heating. Longer timescales greatly improve the diurnal cycle but result in less precipitation and produce a low bias. An analysis of rain rates shows the accurate precipitation amount with the shorter timescale is assembled from an over abundance of drizzle combined with too little heavy rain events. With longer timescales one can improve the distribution, particularly for the extreme rain rates. Ultimately, without changing other aspects of the physics, one must choose between accurate diurnal timing and rain amount when choosing an appropriate convective timescale.« less

  14. Magnetic fields in non-convective regions of stars

    E-Print Network [OSTI]

    Braithwaite, J

    2015-01-01

    We review the current state of knowledge of magnetic fields inside stars, concentrating on recent developments concerning magnetic fields in stably stratified (zones of) stars, leaving out convective dynamo theories and observations of convective envelopes. We include the observational properties of A, B and O-type main-sequence stars, which have radiative envelopes, and the fossil field model which is normally invoked to explain the strong fields sometimes seen in these stars. Observations seem to show that Ap-type stable fields are excluded in stars with convective envelopes. Most stars contain both radiative and convective zones, and there are potentially important effects arising from the interaction of magnetic fields at the boundaries between them, the solar cycle being one of the better known examples. Related to this, we discuss whether the Sun could harbour a magnetic field in its core. Recent developments regarding the various convective and radiative layers near the surfaces of early-type stars and...

  15. Convective Heat Transport in Compressible Fluids

    E-Print Network [OSTI]

    Akira Furukawa; Akira Onuki

    2002-02-01

    We present hydrodynamic equations of compressible fluids in gravity as a generalization of those in the Boussinesq approximation used for nearly incompressible fluids. They account for adiabatic processes taking place throughout the cell (the piston effect) and those taking place within plumes (the adiabatic temperature gradient effect). Performing two-dimensional numerical analysis, we reveal some unique features of plume generation and convection in transient and steady states of compressible fluids. As the critical point is approached, overall temperature changes induced by plume arrivals at the boundary walls are amplified, giving rise to overshoot behavior in transient states and significant noises of the temperature in steady states. The velocity field is suggested to assume a logarithmic profile within boundary layers. Random reversal of macroscopic shear flow is examined in a cell with unit aspect ratio. We also present a simple scaling theory for moderate Rayleigh numbers.

  16. Convectively driven vortex flows in the Sun

    E-Print Network [OSTI]

    J. A. Bonet; I. Marquez; J. Sanchez Almeida; I. Cabello; V. Domingo

    2008-09-23

    We have discovered small whirlpools in the Sun, with a size similar to the terrestrial hurricanes (<~0.5 Mm). The theory of solar convection predicts them, but they had remained elusive so far. The vortex flows are created at the downdrafts where the plasma returns to the solar interior after cooling down, and we detect them because some magnetic bright points (BPs) follow a logarithmic spiral in their way to be engulfed by a downdraft. Our disk center observations show 0.009 vortexes per Mm^2, with a lifetime of the order of 5 min, and with no preferred sense of rotation. They are not evenly spread out over the surface, but they seem to trace the supergranulation and the mesogranulation. These observed properties are strongly biased by our type of measurement, unable to detect vortexes except when they are engulfing magnetic BPs.

  17. Mixed Convection in the VHTR in the Event of a LOFA

    SciTech Connect (OSTI)

    Richard W. Johnson

    2012-05-01

    The US Department of Energy, Office of Nuclear Energy (DOE-NE) is supporting the development of a very high temperature reactor (VHTR) concept as the primary focus of it next generation nuclear power plant (NGNP) program. The VHTR is cooled by forcing helium downwards through the core into the lower plenum and out the hot duct. In the event that the coolant circulators are lost, the driving pressure drop across the core will reduce to zero and there will be the opportunity for natural circulation to occur. During the time that the circulators are powering down, the heat transfer in the core from the graphite blocks to the helium coolant will transform from turbulent forced convection to mixed convection, where buoyancy effects become important, to free or natural convection, where buoyancy is dominant. Analysis of the nature of the forced, mixed and free convection is best done using computational fluid dynamic (CFD) software that can provide fine details of the flow and heat transfer. However, CFD analysis involves approximations in the results because of the finite nature of the spatial and temporal discretizations required, the inexact nature of the turbulence models that are used and the finite precision of the computers employed. Therefore, it is necessary to validate the CFD computations. Validation is accomplished by comparing results from specific CFD computations to experimental data that have been taken specifically for the purpose of validation and that are related to the physical phenomena in question. The present report examines the flow and heat transfer parameters (dimensionless numbers) that characterize the flow and reports ranges for their values based on specific CFD studies performed for the VHTR.

  18. Convective heat transfer characteristics of China RP-3 aviation kerosene at supercritical pressure

    E-Print Network [OSTI]

    Guo, Zhixiong "James"

    Convective heat transfer characteristics of China RP-3 aviation kerosene at supercritical pressure Keywords: Supercritical pressure Aviation kerosene Convective heat transfer Numerical study a b s t r a c convective in kerosene pipe flow is complicated. Here the convective heat transfer characteristics of China

  19. Effect of Convective Entrainment/Detrainment on the Simulation of the Tropical Precipitation Diurnal Cycle*

    E-Print Network [OSTI]

    Wang, Yuqing

    Effect of Convective Entrainment/Detrainment on the Simulation of the Tropical Precipitation the effect of assumed fractional convective entrainment/detrainment rates in the Tiedtke mass flux convective measurements. In a control experiment with the default fractional convective entrainment/detrainment rates

  20. A viscous-convective instability in laminar Keplerian thin discs. II. Anelastic approximation

    E-Print Network [OSTI]

    Shakura, N

    2015-01-01

    Using the anelastic approximation of linearised hydrodynamic equations, we investigate the development of axially symmetric small perturbations in thin Keplerian discs. The sixth-order dispersion equation is derived and numerically solved for different values of relevant physical parameters (viscosity, heat conductivity, disc semi-thickness and vertical structure). The analysis reveals the appearance of two overstable modes which split out from the classical Rayleigh inertial modes in a wide range of the parameters in both ionized and neutral gases. These modes have a viscous-convective nature and can serve as a seed for turbulence in astrophysical discs even in the absence of magnetic fields.

  1. Survey and evaluation of techniques to augment convective heat transfer

    E-Print Network [OSTI]

    Bergles A. E.

    1965-01-01

    This report presents a survey and evaluation of the numerous techniques which have been shown to augment convective heat transfer. These techniques are: surface promoters, including roughness and treatment; displaced ...

  2. Extreme Summer Convection in South America ULRIKE ROMATSCHKE

    E-Print Network [OSTI]

    Houze Jr., Robert A.

    -level suppressed flow of the southeast Pacific from the unstable low-level flow dominating weather over. Knowledge of the details of convection throughout the tropics and subtropics has been revolutionized

  3. Experimental study of internal wave generation by convection in water

    E-Print Network [OSTI]

    2015-01-01

    wave generation by convection in water Michael Le Bars 1,2 ,investigate the dynamics of water cooled from below at 0 ° Cof the unusual property that water’s density maximum is at

  4. Experimental study of internal wave generation by convection in water

    E-Print Network [OSTI]

    Bars, Michael Le; Perrard, Stéphane; Ribeiro, Adolfo; Rodet, Laetitia; Aurnou, Jonathan M; Gal, Patrice Le

    2015-01-01

    We experimentally investigate the dynamics of water cooled from below at 0^oC and heated from above. Taking advantage of the unusual property that water's density maximum is at about 4^oC, this set-up allows us to simulate in the laboratory a turbulent convective layer adjacent to a stably stratified layer, which is representative of atmospheric and stellar conditions. High precision temperature and velocity measurements are described, with a special focus on the convectively excited internal waves propagating in the stratified zone. Most of the convective energy is at low frequency, and corresponding waves are localized to the vicinity of the interface. However, we show that some energy radiates far from the interface, carried by shorter horizontal wavelength, higher frequency waves. Our data suggest that the internal wave field is passively excited by the convective fluctuations, and the wave propagation is correctly described by the dissipative linear wave theory.

  5. NATURAL CONVECTION IN PASSIVE SOLAR BUILDINGS: EXPERIMENTS, ANALYSIS AND RESULTS

    SciTech Connect (OSTI)

    Gadgil, A.; Bauman, F.; Kammerud, R.

    1981-04-01

    Computer programs have been developed to numerically simulate natural convection in two- and three-dimensional room geometries. The programs have been validated using published data from the literature, results from a full-scale experiment performed at the Massachusetts Institute of Technology, and results from a small-scale experiment performed at LBL. One of the computer programs has been used to study the influence of natural convection on the thermal performance of a single zone in a direct-gain passive solar building. It is found that the convective heat transfer coefficients between the air and the enclosure surfaces can be substantially different from the values assumed in the standard building energy analysis methods, and can exhibit significant variations across a given surface. This study implies that the building heating loads calculated by standard building energy analysis methods may have substantial errors as a result of their use of common assumptions regarding the convection processes which occur in an enclosure.

  6. A numerical simulation of slantwise convection: its structure and evolution 

    E-Print Network [OSTI]

    Overpeck, Scott Allen

    2001-01-01

    Weather forecasters have had difficulty forecasting mesoscale precipitation bands occurring in the regions of frontal zones. Within the last twenty years, slantwise convection (SC) through the release of conditional symmetric instability (CSI) has...

  7. TURBULENT CONVECTION IN STELLAR INTERIORS. III. MEAN-FIELD ANALYSIS...

    Office of Scientific and Technical Information (OSTI)

    implicit large eddy simulations of the turbulent convection in the envelope of a 5 Msub Sun red giant star and in the oxygen-burning shell of a 23 Msub Sun supernova...

  8. Fast Explicit Operator Splitting Method for Convection-Diffusion Equations

    E-Print Network [OSTI]

    Kurganov, Alexander

    to the one- and two-dimensional systems of convection-diffusion equations which model the polymer flooding) processes in fluid mechanics, astrophysics, me- teorology, multiphase flow in oil reservoirs, polymer flow

  9. Interaction between surface and atmosphere in a convective boundary layer /

    E-Print Network [OSTI]

    Garai, Anirban

    2013-01-01

    of cold fluid constitute most of the heat transport andevent cold air descends to the ground, heat transport fromcold air during sweep events. The convective boundary layer has a great influence on moisture transport,

  10. Identification of Robust Routes using Convective Weather Forcasts

    E-Print Network [OSTI]

    Michalek, Diana

    Convective weather is responsible for large delays and widespread disruptions in the U.S. National Airspace System (NAS), especially during summer months when travel demand is high. This has been the motivation for Air ...

  11. Identification of Robust Terminal-Area Routes in Convective Weather

    E-Print Network [OSTI]

    Balakrishnan, Hamsa

    Convective weather is responsible for large delays and widespread disruptions in the U.S. National Airspace System, especially during summer. Traffic flow management algorithms require reliable forecasts of route blockage ...

  12. Experimental Investigation of Natural Convection in Trombe Wall Systems 

    E-Print Network [OSTI]

    Chen, B.; Zhao, J.; Chen, C.; Zhuang, Z.

    2006-01-01

    In this paper, experiments with a passive solar building with Trombe wall in the north cold climate are carried out and discussed, and the natural convection heat transfer process has been investigated. The relativity of the factors affecting indoor...

  13. Use of a fictitious Marangoni number for natural convection simulation

    E-Print Network [OSTI]

    Arias, Francisco J.; Parks, Geoffrey T.

    2015-05-14

    - portance in many engineering and scientific applications such as energy transfer, boilers, nuclear reactor systems, energy storage devices, etc. In the design of such systems numerical simulation using computational fluid dynamics (CFD) and experimental... spacing of vertical, natural convection cooled, parallel plates. ASME J. Heat Transfer, 106 (1) (1984), pp. 116–123 [19] C.T. Tran, T.N. Dinh, Simulation of core melt pool formation in a reactor pressure vessel lower head using an effective convective...

  14. Natural convection airflow and heat transport in buildings: experimental results

    SciTech Connect (OSTI)

    Balcomb, J.D.; Jones, G.F.

    1985-01-01

    Observations of natural convection airflow in passive solar buildings are described. Particular results are given for two buildings supplementing other data already published. A number of generalizations based on the monitoring of the 15 buildings are presented. It is concluded that energy can be reasonably well distributed throughout a building by natural convection provided suitable openings are present and that the direction of heat transport is either horizontally across or upward.

  15. Parameterizing deep convection using the assumed probability density function method

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Storer, R. L.; Griffin, B. M.; Höft, J.; Weber, J. K.; Raut, E.; Larson, V. E.; Wang, M.; Rasch, P. J.

    2015-01-06

    Due to their coarse horizontal resolution, present-day climate models must parameterize deep convection. This paper presents single-column simulations of deep convection using a probability density function (PDF) parameterization. The PDF parameterization predicts the PDF of subgrid variability of turbulence, clouds, and hydrometeors. That variability is interfaced to a prognostic microphysics scheme using a Monte Carlo sampling method. The PDF parameterization is used to simulate tropical deep convection, the transition from shallow to deep convection over land, and midlatitude deep convection. These parameterized single-column simulations are compared with 3-D reference simulations. The agreement is satisfactory except when the convective forcingmore »is weak. The same PDF parameterization is also used to simulate shallow cumulus and stratocumulus layers. The PDF method is sufficiently general to adequately simulate these five deep, shallow, and stratiform cloud cases with a single equation set. This raises hopes that it may be possible in the future, with further refinements at coarse time step and grid spacing, to parameterize all cloud types in a large-scale model in a unified way.« less

  16. Parameterizing deep convection using the assumed probability density function method

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Storer, R. L.; Griffin, B. M.; Höft, J.; Weber, J. K.; Raut, E.; Larson, V. E.; Wang, M.; Rasch, P. J.

    2015-01-06

    Due to their coarse horizontal resolution, present-day climate models must parameterize deep convection. This paper presents single-column simulations of deep convection using a probability density function (PDF) parameterization. The PDF parameterization predicts the PDF of subgrid variability of turbulence, clouds, and hydrometeors. That variability is interfaced to a prognostic microphysics scheme using a Monte Carlo sampling method.The PDF parameterization is used to simulate tropical deep convection, the transition from shallow to deep convection over land, and midlatitude deep convection. These parameterized single-column simulations are compared with 3-D reference simulations. The agreement is satisfactory except when the convective forcing is weak.more »The same PDF parameterization is also used to simulate shallow cumulus and stratocumulus layers. The PDF method is sufficiently general to adequately simulate these five deep, shallow, and stratiform cloud cases with a single equation set. This raises hopes that it may be possible in the future, with further refinements at coarse time step and grid spacing, to parameterize all cloud types in a large-scale model in a unified way.« less

  17. Convective heat transfer in buildings: recent research results. Rev

    SciTech Connect (OSTI)

    Bauman, F.; Gadgil, A.; Kammerud, R.; Altmayer, E.; Nansteel, M.W.

    1982-10-01

    Recent experimental and numerical studies of convective heat transfer in buildings are described, and important results are presented. The experimental work has been performed on small-scale, water-filled enclosures; the numerical analysis results have been produced by a computer program based on a finite-difference scheme. The convective processes investigated in this research are: (1) natural convective heat transfer between room surfaces and the adjacent air, (2) natural convective heat transfer between adjacent rooms through a doorway or other openings, and (3) forced convection between the building and its external environment (such as wind-driven ventilation through windows, doors, or other openings). Results obtained at Lawrence Berkeley Laboratory (LBL) for surface convection coefficients are compared with existing ASHRAE correlations, and differences can have a significant impact on the accuracy of building energy analysis computer simulations. Interzone coupling correlations obtained from experimental work are in reasonable agreement with recently published experimental results and with earlier published work. Numerical simulations of wind-driven natural ventilation are presented. They exhibit good qualitative agreement with published wind-tunnel data.

  18. Parameterizing deep convection using the assumed probability density function method

    SciTech Connect (OSTI)

    Storer, R. L. [Univ. of Wisconsin - Milwaukee, Milwaukee, WI (United States); Griffin, B. M. [Univ. of Wisconsin - Milwaukee, Milwaukee, WI (United States); Höft, J. [Univ. of Wisconsin - Milwaukee, Milwaukee, WI (United States); Weber, J. K. [Univ. of Wisconsin - Milwaukee, Milwaukee, WI (United States); Raut, E. [Univ. of Wisconsin - Milwaukee, Milwaukee, WI (United States); Larson, V. E. [Univ. of Wisconsin - Milwaukee, Milwaukee, WI (United States); Wang, M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)] (ORCID:000000029179228X); Rasch, P. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-01-01

    Due to their coarse horizontal resolution, present-day climate models must parameterize deep convection. This paper presents single-column simulations of deep convection using a probability density function (PDF) parameterization. The PDF parameterization predicts the PDF of subgrid variability of turbulence, clouds, and hydrometeors. That variability is interfaced to a prognostic microphysics scheme using a Monte Carlo sampling method.The PDF parameterization is used to simulate tropical deep convection, the transition from shallow to deep convection over land, and midlatitude deep convection. These parameterized single-column simulations are compared with 3-D reference simulations. The agreement is satisfactory except when the convective forcing is weak. The same PDF parameterization is also used to simulate shallow cumulus and stratocumulus layers. The PDF method is sufficiently general to adequately simulate these five deep, shallow, and stratiform cloud cases with a single equation set. This raises hopes that it may be possible in the future, with further refinements at coarse time step and grid spacing, to parameterize all cloud types in a large-scale model in a unified way.

  19. Thermal interaction between free convection and forced convection along a vertical conducting wall

    E-Print Network [OSTI]

    Shu, Jian-Jun

    2015-01-01

    A theoretical study is presented in this paper to investigate the conjugate heat transfer across a vertical finite wall separating two forced and free convection flows at different temperatures. The heat conduction in the wall is in the transversal direction and countercurrent boundary layers are formed on the both sides of the wall. The governing equations of this problem and their corresponding boundary conditions are all cast into a dimensionless form by using a non-similarity transformation. These resultant equations with multiple singular points are solved numerically using a very efficient singular perturbation method. The effects of the resistance parameters and Prandtl numbers on heat transfer characteristics are investigated.

  20. EVIDENCE FOR CONVECTION IN SUNSPOT PENUMBRAE

    SciTech Connect (OSTI)

    Bharti, L.; Solanki, S. K.; Hirzberger, J.

    2010-10-20

    We present an analysis of twisting motions in penumbral filaments in sunspots located at heliocentric angles from 30{sup 0} to 48{sup 0} using three time series of blue continuum images obtained by the Broadband Filter Imager (BFI) on board Hinode. The relations of the twisting motions to the filament brightness and the position within the filament and within the penumbra, respectively, are investigated. Only certain portions of the filaments show twisting motions. In a statistical sense, the part of the twisting portion of a filament located closest to the umbra is brightest and possesses the fastest twisting motion, with a mean twisting velocity of 2.1 km s{sup -1}. The middle and outer sections of the twisting portion of the filament (lying increasingly further from the umbra), which are less bright, have mean velocities of 1.7 km s{sup -1} and 1.35 km s{sup -1}, respectively. The observed reduction of brightness and twisting velocity toward the outer section of the filaments may be due to reducing upflow along the filament's long axis. No significant variation of twisting velocity as a function of viewing angles was found. The obtained correlation of brightness and velocity suggests that overturning convection causes the twisting motions observed in penumbral filament and may be the source of the energy needed to maintain the brightness of the filaments.

  1. RANGE-ENERGY TABLES

    E-Print Network [OSTI]

    Rich, Marvin

    2010-01-01

    Mev gm/ era Mev gm/crn" Mev-cnf/gm 5. 817 x 10" 1. 685 x 10"2301 RANGE OF DEUTERONS IN CARBON J T Mev R gm/cm - dT "dTi T Mev R gm/cm - dT dF Mev- Mev-cn^gm cm/gm 5. 517 x lu" 3.

  2. Evolution of vertical drafts and cloud-to-ground lightning within the convective region of a mesoscale convective complex 

    E-Print Network [OSTI]

    Saul, Scott Henry

    1995-01-01

    The evolution of the area-averaged vertical velocity within the objectively defined convective region of the 4 June 1985 PRE-STORM (Preliminary Regional Experiment for Stormscale Operational and Research Meteorology-Central Phase) mesoscale...

  3. Light beam range finder

    DOE Patents [OSTI]

    McEwan, Thomas E. (Livermore, CA)

    1998-01-01

    A "laser tape measure" for measuring distance which includes a transmitter such as a laser diode which transmits a sequence of electromagnetic pulses in response to a transmit timing signal. A receiver samples reflections from objects within the field of the sequence of visible electromagnetic pulses with controlled timing, in response to a receive timing signal. The receiver generates a sample signal in response to the samples which indicates distance to the object causing the reflections. The timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The receive timing signal causes the receiver to sample the reflection such that the time between transmission of pulses in the sequence in sampling by the receiver sweeps over a range of delays. The transmit timing signal causes the transmitter to transmit the sequence of electromagnetic pulses at a pulse repetition rate, and the received timing signal sweeps over the range of delays in a sweep cycle such that reflections are sampled at the pulse repetition rate and with different delays in the range of delays, such that the sample signal represents received reflections in equivalent time. The receiver according to one aspect of the invention includes an avalanche photodiode and a sampling gate coupled to the photodiode which is responsive to the received timing signal. The transmitter includes a laser diode which supplies a sequence of visible electromagnetic pulses. A bright spot projected on to the target clearly indicates the point that is being measured, and the user can read the range to that point with precision of better than 0.1%.

  4. Light beam range finder

    DOE Patents [OSTI]

    McEwan, T.E.

    1998-06-16

    A ``laser tape measure`` for measuring distance is disclosed which includes a transmitter such as a laser diode which transmits a sequence of electromagnetic pulses in response to a transmit timing signal. A receiver samples reflections from objects within the field of the sequence of visible electromagnetic pulses with controlled timing, in response to a receive timing signal. The receiver generates a sample signal in response to the samples which indicates distance to the object causing the reflections. The timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The receive timing signal causes the receiver to sample the reflection such that the time between transmission of pulses in the sequence in sampling by the receiver sweeps over a range of delays. The transmit timing signal causes the transmitter to transmit the sequence of electromagnetic pulses at a pulse repetition rate, and the received timing signal sweeps over the range of delays in a sweep cycle such that reflections are sampled at the pulse repetition rate and with different delays in the range of delays, such that the sample signal represents received reflections in equivalent time. The receiver according to one aspect of the invention includes an avalanche photodiode and a sampling gate coupled to the photodiode which is responsive to the received timing signal. The transmitter includes a laser diode which supplies a sequence of visible electromagnetic pulses. A bright spot projected on to the target clearly indicates the point that is being measured, and the user can read the range to that point with precision of better than 0.1%. 7 figs.

  5. Neutron range spectrometer

    DOE Patents [OSTI]

    Manglos, S.H.

    1988-03-10

    A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are colliminated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. 1 fig.

  6. Long Range Development Plan

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousand CubicResourcelogo and-E CChinaC L S CLogin HelpLoisLong Range

  7. Low Mach Number Modeling of Convection in Helium Shells on Sub-Chandrasekhar White Dwarfs II: Bulk Properties of Simple Models

    E-Print Network [OSTI]

    Jacobs, Adam M; Nonaka, Andy; Almgren, Ann S; Bell, John B

    2015-01-01

    The dynamics of helium shell convection driven by nuclear burning establish the conditions for runaway in the sub-Chandrasekhar mass, double detonation model for Type Ia supernovae, as well as for a variety of other explosive phenomena. We explore these convection dynamics for a range of white dwarf core and helium shell masses in three dimensions using the low Mach number hydrodynamics code Maestro. We present calculations of the bulk properties of this evolution, including time-series evolution of global diagnostics, lateral averages of the 3D state, and the global 3D state. We find a variety of outcomes including quasi-equilibrium, localized runaway, and nova-like runaway. Our results suggest the double detonation progenitor model is promising, that 3D, dynamic convection plays a key role, and that these systems warrant further study.

  8. Turbulent Convection in Stellar Interiors. II. The Velocity Field

    E-Print Network [OSTI]

    David Arnett; Casey Meakin; P. A. Young

    2008-11-25

    We analyze stellar convection with the aid of 3D hydrodynamic simulations, introducing the turbulent cascade into our theoretical analysis. We devise closures of the Reynolds-decomposed mean field equations by simple physical modeling of the simulations (we relate temperature and density fluctuations via coefficients); the procedure (CABS, Convection Algorithms Based on Simulations) is terrestrially testable and is amenable to systematic improvement. We develop a turbulent kinetic energy equation which contains both nonlocal and time dependent terms, and is appropriate if the convective transit time is shorter than the evolutionary time scale. The interpretation of mixing-length theory (MLT) as generally used in astrophysics is incorrect; MLT forces the mixing length to be an imposed constant. Direct tests show that the damping associated with the flow is that suggested by Kolmogorov. The eddy size is approximately the depth of the convection zone, and this dissipation length corresponds to the "mixing length". New terms involving local heating by turbulent dissipation should appear in the stellar evolution equations. The enthalpy flux ("convective luminosity") is directly connected to the buoyant acceleration, and hence the velocity scale. MLT tends to systematically underestimate this velocity scale. Quantitative comparison with a variety of 3D simulations reveals a previously recognized consistency. Examples of application to stellar evolution will be presented in subsequent papers in this series.

  9. Analysis of 11 june 2003 mesoscale convective vortex genesis using weather surveillance radar ??88 doppler (wsr-88d) 

    E-Print Network [OSTI]

    Reynolds, Amber Elizabeth

    2009-05-15

    Mesoscale convective vortices (MCVs), which typically form within the stratiform rain of some mesoscale convective systems (MCSs), may persist for days, often regenerating convection daily. Long-lived MCVs can produce as much precipitation as a...

  10. ARM - Midlatitude Continental Convective Clouds (comstock-hvps)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Mike; Comstock, Jennifer; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    2012-01-06

    Convective processes play a critical role in the Earth's energy balance through the redistribution of heat and moisture in the atmosphere and their link to the hydrological cycle. Accurate representation of convective processes in numerical models is vital towards improving current and future simulations of Earths climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales important to convective processes and therefore must turn to parameterization schemes to represent these processes. In turn, parameterization schemes in cloud-resolving models need to be evaluated for their generality and application to a variety of atmospheric conditions. Data from field campaigns with appropriate forcing descriptors have been traditionally used by modelers for evaluating and improving parameterization schemes.

  11. ARM - Midlatitude Continental Convective Clouds (comstock-hvps)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Mike; Comstock, Jennifer; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    Convective processes play a critical role in the Earth's energy balance through the redistribution of heat and moisture in the atmosphere and their link to the hydrological cycle. Accurate representation of convective processes in numerical models is vital towards improving current and future simulations of Earths climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales important to convective processes and therefore must turn to parameterization schemes to represent these processes. In turn, parameterization schemes in cloud-resolving models need to be evaluated for their generality and application to a variety of atmospheric conditions. Data from field campaigns with appropriate forcing descriptors have been traditionally used by modelers for evaluating and improving parameterization schemes.

  12. Magneto-Vortex Dynamo Model in Solar convection zone

    E-Print Network [OSTI]

    Sergey V. Ershkov

    2011-01-06

    Here is presented a new magneto-vortex dynamo model for modeling & predicting of a processes in Solar plasma convection zone. Solar convection zone is located above the level r > 0,6-0,7 R, where R is a Solar radius. A key feature of such a model is that equation of Solar plasma motion as well as equation of magnetic fields evolution - are reduced to Helmholtz's vortex equation, which is up-graded in according with alpha-effect (Coriolis force forms an additional vorticity field or magnetic field due to Sun's differential rotation). Such an additional vorticity or magnetic field are proved to be concentrated at the proper belt in Solar convection zone under the influence of Coriolis force (at the middle latitudes of the Sun in respect to equator). Besides, such an an additional vorticity & magnetic fields are to be the basic sources of well-known phenomena "Maunder's butterfly" diagram.

  13. Parametric Sensitivity and Calibration for Kain-Fritsch Convective Parameterization Scheme in the WRF Model

    SciTech Connect (OSTI)

    Yan, Huiping; Qian, Yun; Lin, Guang; Leung, Lai-Yung R.; Yang, Ben; Fu, Q.

    2014-03-25

    Convective parameterizations used in weather and climate models all display sensitivity to model resolution and variable skill in different climatic regimes. Although parameters in convective schemes can be calibrated using observations to reduce model errors, it is not clear if the optimal parameters calibrated based on regional data can robustly improve model skill across different model resolutions and climatic regimes. In this study, this issue is investigated using a regional modeling framework based on the Weather Research and Forecasting (WRF) model. To quantify the response and sensitivity of model performance to model parameters, we identified five key input parameters and specified their ranges in the Kain-Fritsch (KF) convection scheme in WRF and calibrated them across different spatial resolutions, climatic regimes, and radiation schemes using observed precipitation data. Results show that the optimal values for the five input parameters in the KF scheme are close and model sensitivity and error exhibit similar dependence on the input parameters for all experiments conducted in this study despite differences in the precipitation climatology. We found that the model overall performances in simulating precipitation are more sensitive to the coefficients of downdraft (Pd) and entrainment (Pe) mass flux and starting height of downdraft (Ph). However, we found that rainfall biases, which are probably more related to structural errors, still exist over some regions in the simulation even with the optimal parameters, suggesting further studies are needed to identify the sources of uncertainties and reduce the model biases or structural errors associated with missed or misrepresented physical processes and/or potential problems with the modeling framework.

  14. A meshless method for modeling convective heat transfer

    SciTech Connect (OSTI)

    Carrington, David B

    2010-01-01

    A meshless method is used in a projection-based approach to solve the primitive equations for fluid flow with heat transfer. The method is easy to implement in a MATLAB format. Radial basis functions are used to solve two benchmark test cases: natural convection in a square enclosure and flow with forced convection over a backward facing step. The results are compared with two popular and widely used commercial codes: COMSOL, a finite element model, and FLUENT, a finite volume-based model.

  15. Staggered grids discretization in three-dimensional Darcy convection

    E-Print Network [OSTI]

    B. Karasozen; A. D. Nemtsev; V. G. Tsybulin

    2008-02-17

    We consider three-dimensional convection of an incompressible fluid saturated in a parallelepiped with a porous medium. A mimetic finite-difference scheme for the Darcy convection problem in the primitive variables is developed. It consists of staggered nonuniform grids with five types of nodes, differencing and averaging operators on a two-nodes stencil. The nonlinear terms are approximated using special schemes. Two problems with different boundary conditions are considered to study scenarios of instability of the state of rest. Branching off of a continuous family of steady states was detected for the problem with zero heat fluxes on two opposite lateral planes.

  16. Midlatitude Continental Convective Clouds Experiment (MC3E)

    SciTech Connect (OSTI)

    Jensen, MP; Petersen, WA; Del Genio, AD; Giangrande, SE; Heymsfield, A; Heymsfield, G; Hou, AY; Kollias, P; Orr, B; Rutledge, SA; Schwaller, MR; Zipser, E

    2010-04-01

    Convective processes play a critical role in the Earth’s energy balance through the redistribution of heat and moisture in the atmosphere and subsequent impacts on the hydrologic cycle. Global observation and accurate representation of these processes in numerical models is vital to improving our current understanding and future simulations of Earth’s climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales that are associated with convective and stratiform precipitation processes; therefore, they must turn to parameterization schemes to represent these processes. In turn, the physical basis for these parameterization schemes needs to be evaluated for general application under a variety of atmospheric conditions. Analogously, space-based remote sensing algorithms designed to retrieve related cloud and precipitation information for use in hydrological, climate, and numerical weather prediction applications often rely on physical “parameterizations” that reliably translate indirectly related instrument measurements to the physical quantity of interest (e.g., precipitation rate). Importantly, both spaceborne retrieval algorithms and model convective parameterization schemes traditionally rely on field campaign data sets as a basis for evaluating and improving the physics of their respective approaches. The Midlatitude Continental Convective Clouds Experiment (MC3E) will take place in central Oklahoma during the April–May 2011 period. The experiment is a collaborative effort between the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility and the National Aeronautics and Space Administration’s (NASA) Global Precipitation Measurement (GPM) mission Ground Validation (GV) program. The field campaign leverages the unprecedented observing infrastructure currently available in the central United States, combined with an extensive sounding array, remote sensing and in situ aircraft observations, NASA GPM ground validation remote sensors, and new ARM instrumentation purchased with American Recovery and Reinvestment Act funding. The overarching goal is to provide the most complete characterization of convective cloud systems, precipitation, and the environment that has ever been obtained, providing constraints for model cumulus parameterizations and space-based rainfall retrieval algorithms over land that have never before been available. Several different components of convective cloud and precipitation processes tangible to both the convective parameterization and precipitation retrieval algorithm problem are targeted, such as preconvective environment and convective initiation, updraft/downdraft dynamics, condensate transport and detrainment, precipitation and cloud microphysics, spatial and temporal variability of precipitation, influence on the environment and radiation, and a detailed description of the large-scale forcing.

  17. Semi-convection: What is the underlying physical context?

    E-Print Network [OSTI]

    Noels, Arlette

    2015-01-01

    Stellar conditions leading to a possible semi-convective mixing are discussed in three relevant cases: (1) low mass MS stars in which the CNO cycle takes progressively the lead over the PP chain due to the increase in temperature as core hydrogen burning proceeds, (2) massive MS stars which experience a large contri- bution of the radiation pressure to the total pressure and (3) core helium burning stars for which the production of carbon in the core increases the opacity. A short discussion of semi-convection in terms of instability of non radial modes follows.

  18. The influence of convective activity on the vorticity budget 

    E-Print Network [OSTI]

    Townsend, Tamara L

    1987-01-01

    . Continued. ~E' i~ QE I ~ tt Jtm a tt NE v~ l / tmt ta' NE ~~f IIIY G NE~~ NE a/+ NE NE NE NE 1st NE Fig. 13. Radar summary for 1435 GNT 10 Apri. l 1979. NE I l. c I E j~7 ~ NE NE MP- Qo+ Fig. 14. Radar summary for 2235 GMT 10 April 1979... experiment. 15 3 Average values of terms in the vorticity equation for a convective (Area 1) and a nonconvective (Area 2) area during AVE VII. Units of 10 s 145 4 Average values of terms in the vorticity equation for a convective (Area 1) and a...

  19. Neutron range spectrometer

    DOE Patents [OSTI]

    Manglos, Stephen H. (East Syracuse, NY)

    1989-06-06

    A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are collimnated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. The computer solves the following equation in the analysis: ##EQU1## where: N(x).DELTA.x=the number of neutron interactions measured between a position x and x+.DELTA.x, A.sub.i (E.sub.i).DELTA.E.sub.i =the number of incident neutrons with energy between E.sub.i and E.sub.i +.DELTA.E.sub.i, and C=C(E.sub.i)=N .sigma.(E.sub.i) where N=the number density of absorbing atoms in the position sensitive counter means and .sigma. (E.sub.i)=the average cross section of the absorbing interaction between E.sub.i and E.sub.i +.DELTA.E.sub.i.

  20. Forced-convection surface-boiling heat transfer and burnout in tubes of small diameters

    E-Print Network [OSTI]

    Bergles A. E.

    1962-01-01

    A basic heat-transfer apparatus was designed and constructed for the study of forced-convection boiling in small channels. The various regions of forced-convection surface boiling were studied experimentally and analytically. ...

  1. THE DOMINANCE OF NEUTRINO-DRIVEN CONVECTION IN CORE-COLLAPSE...

    Office of Scientific and Technical Information (OSTI)

    THE DOMINANCE OF NEUTRINO-DRIVEN CONVECTION IN CORE-COLLAPSE SUPERNOVAE Citation Details In-Document Search Title: THE DOMINANCE OF NEUTRINO-DRIVEN CONVECTION IN CORE-COLLAPSE...

  2. Lake-size dependency of wind shear and convection as controls on gas exchange

    E-Print Network [OSTI]

    California at Santa Barbara, University of

    Lake-size dependency of wind shear and convection as controls on gas exchange Jordan S. Read,1 the relative contributions of wind shear (u*) and convection (w*) to turbulence in the surface mixed layer wind shear (u*/w*

  3. Heat transport in boiling turbulent Rayleigh-B\\'{e}nard convection

    E-Print Network [OSTI]

    Lakkaraju, Rajaram; Oresta, Paolo; Verzicco, Roberto; Lohse, Detlef; Prosperetti, Andrea

    2014-01-01

    Boiling is an extremely effective way to promote heat transfer from a hot surface to a liquid due to several mechanisms many of which are not understood in quantitative detail. An important component of the overall process is that the buoyancy of the bubbles compounds with that of the liquid to give rise to a much enhanced natural convection. In this paper we focus specifically on this enhancement and present a numerical study of the resulting two-phase Rayleigh-B\\'enard convection process. We make no attempt to model other aspects of the boiling process such as bubble nucleation and detachment. We consider a cylindrical cell with a diameter equal to its height. The cell base and top are held at temperatures above and below the boiling point of the liquid, respectively. By keeping the temperature difference constant and changing the liquid pressure we study the effect of the liquid superheat in a Rayleigh number range that, in the absence of boiling, would be between $2\\times10^6$ and $5\\times10^9$. We find a...

  4. Scaling behavior in the convection-driven Brazil-nut effect

    E-Print Network [OSTI]

    Prakhyat Hejmady; Ranjini Bandyopadhyay; Sanjib Sabhapandit; Abhishek Dhar

    2012-11-22

    The Brazil-nut effect is the phenomenon in which a large intruder particle immersed in a vertically shaken bed of smaller particles rises to the top, even when it is much denser. The usual practice, while describing these experiments, has been to use the dimensionless acceleration \\Gamma=a \\omega^2/g, where a and \\omega are respectively the amplitude and the angular frequency of vibration and g is the acceleration due to gravity. Considering a vibrated quasi-two-dimensional bed of mustard seeds, we show here that the peak-to-peak velocity of shaking v= a\\omega, rather than \\Gamma, is the relevant parameter in the regime where boundary-driven granular convection is the main driving mechanism. We find that the rise-time \\tau of an intruder is described by the scaling law \\tau ~ (v-v_c)^{-\\alpha}, where v_c is identified as the critical vibration velocity for the onset of convective motion of the mustard seeds. This scaling form holds over a wide range of (a,\\omega), diameter and density of the intruder.

  5. Stochasticity and efficiency of convection-dominated vs. SASI-dominated supernova explosions

    E-Print Network [OSTI]

    Cardall, Christian Y

    2015-01-01

    We present an initial report on 160 simulations of a highly simplified model of the post-bounce supernova environment in three spatial dimensions (3D). We set different values of a parameter characterizing the impact of nuclear dissociation at the stalled shock in order to regulate the post-shock fluid velocity, thereby determining the relative importance of convection and the stationary accretion shock instability (SASI). While our convection-dominated runs comport with the paradigmatic notion of a `critical neutrino luminosity' for explosion at a given mass accretion rate (albeit with a nontrivial spread in explosion times just above threshold), the outcomes of our SASI-dominated runs are much more stochastic: a sharp threshold critical luminosity is `smeared out' into a rising probability of explosion over a $\\sim 20\\%$ range of luminosity. We also find that the SASI-dominated models are able to explode with 3 to 4 times less efficient neutrino heating, indicating that progenitor properties, and fluid and ...

  6. Deep convection in the Irminger Sea forced by the Greenland tip jet

    E-Print Network [OSTI]

    Deep convection in the Irminger Sea forced by the Greenland tip jet Robert S. Pickart*, Michael A ........................................................................................................................................................................................................................... Open-ocean deep convection, one of the processes by which deep waters of the world's oceans are formed, the southwest Irminger Sea has been suggested as an additional location for open-ocean deep convection. The deep

  7. Deep convection and brine rejection in the Japan Sea Lynne D. Talley

    E-Print Network [OSTI]

    Talley, Lynne D.

    Deep convection and brine rejection in the Japan Sea Lynne D. Talley Scripps Institution groups. Japan Sea deep convection apparently occurs every winter, but massive renewal of bottom waters. Salyuk, P. Tishchenko, I. Zhabin, and S. Riser, Deep convection and brine rejection in the Japan Sea

  8. Geographical distribution and interseasonal variability of tropical deep convection: UARS MLS observations and analyses

    E-Print Network [OSTI]

    Wang, Bin

    of water vapor maxima near the bottom of TTL are located directly above the deep convection centersGeographical distribution and interseasonal variability of tropical deep convection: UARS MLS December 2003; published 13 February 2004. [1] Tropical deep convection and its dynamical effect

  9. Practical and Intrinsic Predictability of Severe and Convective Weather at the Mesoscales

    E-Print Network [OSTI]

    Practical and Intrinsic Predictability of Severe and Convective Weather at the Mesoscales at the mesoscales using convection-permitting ensemble simulations of a squall line and bow echo event during the Bow Echo and Mesoscale Convective Vortex (MCV) Experiment (BAMEX) on 9­10 June 2003. Although most

  10. Charge rearrangement by sprites over a north Texas mesoscale convective system

    E-Print Network [OSTI]

    Cummer, Steven A.

    Charge rearrangement by sprites over a north Texas mesoscale convective system William W. Hager,1 is analyzed for a mesoscale convective system (MCS) situated in north Texas and east New Mexico on 15 July. Lapierre (2012), Charge rearrangement by sprites over a north Texas mesoscale convective system, J. Geophys

  11. AcceptedArticleThe effect of moist convection on thermally induced mesoscale circulations

    E-Print Network [OSTI]

    Gentine, Pierre

    AcceptedArticleThe effect of moist convection on thermally induced mesoscale circulations Malte of thermally induced mesoscale circulations rests primarily on observations and model studies of dry convection-eddy simulations are used to investigate the effect of moist convection on an idealized mesoscale circulation

  12. THE ROLE OF CLOUD MICROPHYSICS PARAMETERIZATION IN THE SIMULATION OF MESOSCALE CONVECTIVE SYSTEMS AND ANVIL

    E-Print Network [OSTI]

    THE ROLE OF CLOUD MICROPHYSICS PARAMETERIZATION IN THE SIMULATION OF MESOSCALE CONVECTIVE SYSTEMS in the Simulation of Mesoscale Convective Systems and Anvil Clouds in the Tropical Western Pacific K. Van Weverberg1 cloud microphysics in the simulation of mesoscale convective systems (MCSs) in the tropical western

  13. The Role of Cumulus Convection in Hurricanes and its Representation in Hurricane Models

    E-Print Network [OSTI]

    Smith, Roger K.

    1 The Role of Cumulus Convection in Hurricanes and its Representation in Hurricane Models By Roger understanding of the role of cumulus convection in hurricanes as well as the various convective parameterization are able to simulate hurricane intensi cation with some degree of realism. In a weak vortex, the secondary

  14. Patterns of Precipitation and Mesolow Evolution in Midlatitude Mesoscale Convective Vortices

    E-Print Network [OSTI]

    Johnson, Richard H.

    Patterns of Precipitation and Mesolow Evolution in Midlatitude Mesoscale Convective Vortices ERIC P manifestations of mesoscale convective vortices (MCVs) that traversed Oklahoma during the periods May­August 2002 Profiler Network data. Forty-five MCVs that developed from mesoscale convective systems (MCSs) have been

  15. Transient luminous events above two mesoscale convective systems: Charge moment change analysis

    E-Print Network [OSTI]

    Cummer, Steven A.

    Transient luminous events above two mesoscale convective systems: Charge moment change analysis. A. Rutledge, and D. R. MacGorman (2011), Transient luminous events above two mesoscale convective in the stratiform region of a mesoscale convective system (MCS) [Houze et al., 1990] by energetic positive CG (+CG

  16. The effect of increased convective entrainment on Asian monsoon biases in

    E-Print Network [OSTI]

    Wirosoetisno, Djoko

    The effect of increased convective entrainment on Asian monsoon biases in the MetUM General) The effect of increased convective entrainment on Asian monsoon biases in the MetUM General Circulation Model The effect of increased convective entrainment on Asian monsoon biases in the MetUM general circulation model

  17. EXPERIMENTAL INVESTIGATION OF NATURAL CONVECTION HEAT TRANSFER OF IONIC LIQUID IN A RECTANGULAR ENCLOSURE HEATED FROM BELOW

    SciTech Connect (OSTI)

    Fox, E.; Visser, A.; Bridges, N.

    2011-07-18

    This paper presents an experimental study of natural convection heat transfer for an Ionic Liquid. The experiments were performed for 1-butyl-2, 3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, ([C{sub 4}mmim][NTf{sub 2}]) at a Raleigh number range of 1.26 x 10{sup 7} to 8.3 x 10{sup 7}. In addition to determining the convective heat transfer coefficients, this study also included experimental determination of thermophysical properties of [C{sub 4}mmim][NTf{sub 2}] such as, density, viscosity, heat capacity, and thermal conductivity. The results show that the density of [C{sub 4}mmim][NTf{sub 2}] varies from 1.437-1.396 g/cm{sup 3} within the temperature range of 10-50 C, the thermal conductivity varies from 0.105-0.116 W/m.K between a temperature of 10 to 60 C, the heat capacity varies from 1.015 J/g.K - 1.760 J/g.K within temperature range of 25-340 C and the viscosity varies from 18cp-243cp within temperature range 10-75 C. The results for density, thermal conductivity, heat capacity, and viscosity were in close agreement with the values in the literature. Measured dimensionless Nusselt number was observed to be higher for the ionic liquid than that of DI water. This is expected as Nusselt number is the ratio of heat transfer by convection to conduction and the ionic liquid has lower thermal conductivity (approximately 18%) than DI water.

  18. Logarithmic corrections to scaling in turbulent thermal convection

    E-Print Network [OSTI]

    B. Dubrulle

    2001-01-04

    We use an analytic toy model of turbulent convection to show that most of the scaling regimes are spoiled by logarithmic corrections, in a way consistent with the most accurate experimental measurements available nowadays. This sets a need for the search of new measurable quantities which are less prone to dimensional theories.

  19. Convection venting lensed reflector-type compact fluorescent lamp system

    DOE Patents [OSTI]

    Pelton, B.A.; Siminovitch, M.

    1997-07-29

    Disclosed herein is a fluorescent lamp housing assembly capable of providing convection cooling to the lamp and the ballast. The lens of the present invention includes two distinct portions, a central portion and an apertured portion. The housing assembly further includes apertures so that air mass is able to freely move up through the assembly and out ventilation apertures. 12 figs.

  20. Overshooting Convection from High-resolution NEXRAD Observations 

    E-Print Network [OSTI]

    Solomon, David

    2014-01-09

    are compared to the lapse-rate tropopause height calculated using the ERA-Interim reanalysis to determine if a storm is overshooting. We compute a 1-year analysis of overshooting convection at three-hour intervals for 2004 for the continental U.S. east...

  1. Investigation of the heat pipe arrays for convective electronic cooling 

    E-Print Network [OSTI]

    Howard, Alicia Ann Harris

    1993-01-01

    A combined experimental and analytical investigation was conducted to evaluate a heat pipe convective cooling device consisting of sixteen small copper/water heat pipes mounted vertically in a 4x4 array 25.4 mm square. The analytical portion...

  2. Modeling thermal convection in supradetachment basins: example from western Norway

    E-Print Network [OSTI]

    Andersen, Torgeir Bjørge

    Modeling thermal convection in supradetachment basins: example from western Norway A. SOUCHE*, M. DABROWSKI AND T. B. ANDERSEN Physics of Geological Processes (PGP), University of Oslo, Oslo, Norway basins of western Norway are examples of supradetachment basins that formed in the hanging wall

  3. Evaporatively Driven Convection in a Draining Soap Film

    E-Print Network [OSTI]

    Bush, John W.M.

    Evaporatively Driven Convection in a Draining Soap Film Submitted by Jan M. Skotheim and John W. M. Bush, MIT A soap film was created by dipping a rectangular wire frame of height 3.5 cm and width 15 cm was mounted in a vertical po- sition, and the film drained under the influence of gravity in an unsaturated

  4. Simulation of Convection and Macrosegregation in a Large Steel Ingot

    E-Print Network [OSTI]

    Beckermann, Christoph

    convection and macrosegregation in casting of a large steel ingot are numerically simulated. The simulation of a shrinkage cavity at the top, is taken into account. The numerical results show the evolution macrosegregation observed in the lower part of the ingot. It is also shown that the inclusion of the shrinkage

  5. Nonequilibrium pattern formation and spatiotemporal chaos in fluid convection

    SciTech Connect (OSTI)

    Michael Cross

    2006-09-13

    The final report for grant number DE-FG03-98ER14891 summarizes the application of the unique simulation capabilities developed under DOE support to investigations of important issues in pattern formation and spatiotemporal chaos in Rayleigh-Benard convection, particularly emphasizing quantitative contact with the active experimental programs.

  6. Preparation, Biodistribution and Neurotoxicity of Liposomal Cisplatin following Convection Enhanced

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Preparation, Biodistribution and Neurotoxicity of Liposomal Cisplatin following Convection Enhanced delivery (CED) to F98 glioma bearing rats. Neurotoxicologic studies were carried out in non-tumor bearing. Unexpectedly, LipoplatinTM was highly neurotoxic when given i.c. by CED and resulted in death immediately

  7. UNCORRECTED Grid geometry effects on convection in ocean climate models

    E-Print Network [OSTI]

    Kuhlbrodt, Till

    is the 12 improvement of convection parameterization schemes, but the question of grid geometry also plays.elsevier.com/locate/omodol OCEMOD 100 No. of Pages 18, DTD = 4.3.1 28 August 2003 Type ARTICLE IN PRESS #12;UNCORRECTED PROOF 26 1 density gradient actually vanishes, one observes a strong vertical turbulent mixing to 32 depths of 2 km

  8. A CONVECTIVE HEAT TRANSFER MODEL FOR SIMULATION OF ROOMS WITH

    E-Print Network [OSTI]

    Quest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, MI 48106-1346 by ProQuest Information and Learning Company. #12;II A CONVECTIVE HEAT TRANSFER MODEL FOR SIMULATION OF ROOMS. Seeing him grow gave me a new level of energy and hope. Without a doubt, my family members have been

  9. IMPACT OF AEROSOLS ON CONVECTIVE CLOUDS AND PRECIPITATION

    E-Print Network [OSTI]

    Zeng, Ning

    IMPACT OF AEROSOLS ON CONVECTIVE CLOUDS AND PRECIPITATION Wei-Kuo Tao,1 Jen-Ping Chen,2 Zhanqing Li effects on clouds could further extend to precipitation, both through the formation of cloud particles mechan- isms behind these effects, in particular, the ones connected to precipitation, are not yet well

  10. Development of Ensemble Neural Network Convection Parameterizations for Climate Models

    SciTech Connect (OSTI)

    Fox-Rabinovitz, M. S.; Krasnopolsky, V. M.

    2012-05-02

    The novel neural network (NN) approach has been formulated and used for development of a NN ensemble stochastic convection parametrization for climate models. This fast parametrization is built based on data from Cloud Resolving Model (CRM) simulations initialized with and forced by TOGA-COARE data. The SAM (System for Atmospheric Modeling), developed by D. Randall, M. Khairoutdinov, and their collaborators, has been used for CRM simulations. The observational data are also used for validation of model simulations. The SAM-simulated data have been averaged and projected onto the GCM space of atmospheric states to implicitly define a stochastic convection parametrization. This parametrization is emulated using an ensemble of NNs. An ensemble of NNs with different NN parameters has been trained and tested. The inherent uncertainty of the stochastic convection parametrization derived in such a way is estimated. Due to these inherent uncertainties, NN ensemble is used to constitute a stochastic NN convection parametrization. The developed NN convection parametrization have been validated in a diagnostic CAM (CAM-NN) run vs. the control CAM run. Actually, CAM inputs have been used, at every time step of the control/original CAM integration, for parallel calculations of the NN convection parametrization (CAM-NN) to produce its outputs as a diagnostic byproduct. Total precipitation (P) and cloudiness (CLD) time series, diurnal cycles, and P and CLD distributions for the large Tropical Pacific Ocean for the parallel CAM-NN and CAM runs show similarity and consistency with the NCEP reanalysis. The P and CLD distributions for the tropical area for the parallel runs have been analyzed first for the TOGA-COARE boreal winter season (November 1992 through February 1993) and then for the winter seasons of the follow-up parallel decadal simulations. The obtained results are encouraging and practically meaningful. They show the validity of the NN approach. This constitutes an important practical conclusion of the study: the obtained results on NN ensembles as a stochastic physics parametrization show a realistic possibility of development of NN convection parametrization for climate (and NWP) models based on learning cloud physics from CRM/SAM simulated data.

  11. HIGH-RESOLUTION CALCULATION OF THE SOLAR GLOBAL CONVECTION WITH THE REDUCED SPEED OF SOUND TECHNIQUE. II. NEAR SURFACE SHEAR LAYER WITH THE ROTATION

    SciTech Connect (OSTI)

    Hotta, H.; Rempel, M. [High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO (United States); Yokoyama, T., E-mail: hotta@ucar.edu [Department of Earth and Planetary Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2015-01-01

    We present a high-resolution, highly stratified numerical simulation of rotating thermal convection in a spherical shell. Our aim is to study in detail the processes that can maintain a near surface shear layer (NSSL) as inferred from helioseismology. Using the reduced speed of sound technique, we can extend our global convection simulation to 0.99 R {sub ?} and include, near the top of our domain, small-scale convection with short timescales that is only weakly influenced by rotation. We find the formation of an NSSL preferentially in high latitudes in the depth range of r = 0.95-0.975 R {sub ?}. The maintenance mechanisms are summarized as follows. Convection under the weak influence of rotation leads to Reynolds stresses that transport angular momentum radially inward in all latitudes. This leads to the formation of a strong poleward-directed meridional flow and an NSSL, which is balanced in the meridional plane by forces resulting from the ?v{sub r}{sup ?}v{sub ?}{sup ?}? correlation of turbulent velocities. The origin of the required correlations depends to some degree on latitude. In high latitudes, a positive correlation ?v{sub r}{sup ?}v{sub ?}{sup ?}? is induced in the NSSL by the poleward meridional flow whose amplitude increases with the radius, while a negative correlation is generated by the Coriolis force in bulk of the convection zone. In low latitudes, a positive correlation ?v{sub r}{sup ?}v{sub ?}{sup ?}? results from rotationally aligned convection cells ({sup b}anana cells{sup )}. The force caused by these Reynolds stresses is in balance with the Coriolis force in the NSSL.

  12. Effect of shear and magnetic field on the heat-transfer efficiency of convection in rotating spherical shells

    E-Print Network [OSTI]

    Yadav, Rakesh K; Christensen, Ulrich R; Duarte, Lucia; Reiners, Ansgar

    2015-01-01

    We study rotating thermal convection in spherical shells as prototype for flow in the cores of terrestrial planets, gas planets or in stars. We base our analysis on a set of about 450 direct numerical simulations of the (magneto)hydrodynamic equations under the Boussinesq approximation. The Ekman number ranges from $10^{-3}$ to $10^{-6}$. Four sets of simulations are considered: non-magnetic simulations and dynamo simulations with either free-slip or no-slip flow boundary conditions. The non-magnetic setup with free-slip boundaries generates the strongest zonal flows. Both non-magnetic simulations with no-slip flow boundary conditions and self-consistent dynamos with free-slip boundaries have drastically reduced zonal-flows. Suppression of shear leads to a substantial gain in heat-transfer efficiency, increasing by a factor of 3 in some cases. Such efficiency enhancement occurs as long as the convection is significantly influenced by rotation. At higher convective driving the heat-transfer efficiency trends t...

  13. The Spectral Amplitude of Stellar Convection and its Scaling in the High-Rayleigh-Number Regime

    E-Print Network [OSTI]

    Featherstone, Nicholas A

    2015-01-01

    Convection plays a central role in the dynamics of any stellar interior, and yet its operation remains largely-hidden from direct observation. As a result, much of our understanding concerning stellar convection necessarily derives from theoretical and computational models. The Sun is, however, exceptional in that regard. The wealth of observational data afforded by its proximity provides a unique testbed for comparing convection models against observations. When such comparisons are carried out, surprising inconsistencies between those models and observations become apparent. Both photospheric and helioseismic measurements suggest that convection simulations may overestimate convective flow speeds on large spatial scales. Moreover, many solar convection simulations have difficulty reproducing the observed solar differential rotation due to this apparent overestimation. We present a series of 3-dimensional (3-D) stellar convection simulations designed to examine how the amplitude and spectral distribution of ...

  14. Timescale of asteroid resurfacing by regolith convection resulting from the impact-induced global seismic shaking

    E-Print Network [OSTI]

    Yamada, Tomoya M; Morota, Tomokatsu; Katsuragi, Hiroaki

    2015-01-01

    A model for the asteroid resurfacing by regolith convection is built to estimate its timescale. In the model, regolith convection is driven by the impact-induced global seismic shaking. The model consists of three steps: (i) intermittent impact of meteors, (ii) impact-induced global vibration (seismic shaking), and (iii) vibration-induced regolith convection. In order to assess the feasibility of the resurfacing process driven by the regolith convection, we estimate the resurfacing timescale as a function of the size of a target asteroid. According to the estimated result, the regolith-convection-based resurfacing timescale is sufficiently shorter than the mean collisional lifetime for the main belt asteroids. This means that the regolith convection is a possible mechanism for the asteroid resurfacing process. However, the timescale depends on various uncertain parameters such as seismic efficiency and convective roll size. To clarify the parameter dependences, we develop an approximated scaling form for the ...

  15. Effective range function below threshold

    E-Print Network [OSTI]

    A. Deloff

    2000-06-26

    We demonstrate that the kernel of the Lippmann-Schwinger equation, associated with interactions consisting of a sum of the Coulomb plus a short range nuclear potential, below threshold becomes degenerate. Taking advantage of this fact, we present a simple method of calculating the effective range function for negative energies. This may be useful in practice since the effective range expansion extrapolated to threshold allows to extract low-energy scattering parameters: the Coulomb-modified scattering length and the effective range.

  16. Land–Ocean Warming Contrast over a Wide Range of Climates: Convective Quasi-Equilibrium Theory and Idealized Simulations

    E-Print Network [OSTI]

    Byrne, Michael Patrick

    Surface temperatures increase at a greater rate over land than ocean in simulations and observations of global warming. It has previously been proposed that this land–ocean warming contrast is related to different changes ...

  17. Numerical study of thermoacoustic convection in a cavity

    SciTech Connect (OSTI)

    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.

  18. Thermodynamic properties of mesoscale convective systems observed during BAMEX

    SciTech Connect (OSTI)

    Correia, James; Arritt, R.

    2008-11-01

    Dropsonde observations from the Bow-echo and Mesoscale convective vortex EXperiment (BAMEX) are used to document the spatio-temporal variability of temperature, moisture and wind within mesoscale convective systems (MCSs). Onion type sounding structures are found throughout the stratiform region of MCSs but the temperature and moisture variability is large. Composite soundings were constructed and statistics of thermodynamic variability were generated within each sub-region of the MCS. The calculated air vertical velocity helped identify subsaturated downdrafts. We found that lapse rates within the cold pool varied markedly throughout the MCS. Layered wet bulb potential temperature profiles seem to indicate that air within the lowest several km comes from a variety of source regions. We also found that lapse rate transitions across the 0 C level were more common than isothermal, melting layers. We discuss the implications these findings have and how they can be used to validate future high resolution numerical simulations of MCSs.

  19. Midlatitude Continental Convective Clouds Experiment (MC3E)

    SciTech Connect (OSTI)

    Jensen, MP; Petersen, WA; Del Genio, AD; Giangrande, SE; Heymsfield, A; Heymsfield, G; Hou, AY; Kollias, P; Orr, B; Rutledge, SA; Schwaller, MR; Zipser, E

    2010-04-10

    The Midlatitude Continental Convective Clouds Experiment (MC3E) will take place in central Oklahoma during the April–May 2011 period. The experiment is a collaborative effort between the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility and the National Aeronautics and Space Administration’s (NASA) Global Precipitation Measurement (GPM) mission Ground Validation (GV) program. The field campaign leverages the unprecedented observing infrastructure currently available in the central United States, combined with an extensive sounding array, remote sensing and in situ aircraft observations, NASA GPM ground validation remote sensors, and new ARM instrumentation purchased with American Recovery and Reinvestment Act funding. The overarching goal is to provide the most complete characterization of convective cloud systems, precipitation, and the environment that has ever been obtained, providing constraints for model cumulus parameterizations and space-based rainfall retrieval algorithms over land that have never before been available.

  20. Gradients of meteorological parameters in convective and nonconvective areas 

    E-Print Network [OSTI]

    McCown, Milton Samuel

    1976-01-01

    involve horizontal gradients. For example, the equations of motion relate wind speed to pressure gradient, and the thermal wind equation relates vertical wind shear to the horizontal temperature gradient. The study of gradients may help... GRADIENTS OF METEOROLOGICAL PARAMETERS IN CONVECTIVE AND NONCONVECTIVE AREAS A Thesis by Milton Samuel McCown Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree of MASTER...

  1. Investigation of convective activity by means of sferics 

    E-Print Network [OSTI]

    Snyder, Louis Archie

    1958-01-01

    that the associ- ation between sfarics data and convective activity may be better inter- prefed and thus extend our knowledge of this problem, PRESENT STATUS OF KNOWLEDGE Atmospherics or "sferics, " commonly associated with radio static, are electromagnetic... east of El Dorado, Oklahoma (20 miles southwest of Altus), at 1918 CST. The echo south of Altus (Fi. g. 26) appeared to be associated with this tornado even though only a weak sferics bearing was recorded at the time. Further study of the sferics...

  2. Deep meridional circulation below the solar convective envelope

    E-Print Network [OSTI]

    K. M. Hiremath

    2008-03-08

    With reasonable assumptions and approximations, we compute the velocity of the meridional flow $U$ in the convective envelope by modified Chandrasekhar's (1956) MHD equations. The analytical solution of such a modified equation is found to be $U(x,\\mu) = \\sum_{n=0}^\\infty \\bigl[u1_n x^n + u2_n x^{-(n+3)}\\bigr] C_n^{3/2}(\\mu)$, where $x$ is non-dimensional radius, $\\mu = cos{\\vartheta}$, ${\\vartheta}$ is the co-latitude, $C_n^{3/2} {(\\mu)}$ are the Gegenbaur polynomials of order 3/2, $u1_n$ and $u2_n$ are the unknown constants. The results show that meridional velocity flow from the surface appears to penetrates deep below base of the convective envelope and at outer part of the radiative zone. With such a deep flow velocity below the convective envelope and a very high density stratification in the outer part of the radiative zone with likely existence of a strong ($\\sim$ $10^{4}$ G) toroidal magnetic field structure, the velocity of transport of meridional flow is considerably reduced. Hence, it is very unlikely that the return flow will reach the surface (with a period of solar cycle) as required by some of the flux transport dynamo models. On the other hand, deep meridional flow is required for burning of Lithium at outer part of the radiative zone supporting the observed Lithium deficiency at the surface.

  3. New dynamics of the Sun convection zone and global warming

    E-Print Network [OSTI]

    Bershadskii, A

    2008-01-01

    Solar activity is studied using cluster analysis of the sunspot number time-fluctuations. It is shown that for a Historic period (1850-1932yy) the cluster exponent $\\alpha \\simeq 0.37$ (strong clustering) for the high activity components of the solar cycles, whereas for a Modern period (last seven solar cycles: 1933-2007) the cluster exponent $\\alpha \\simeq 0.50$ (random, white noise-like situation). Then, comparing these results with the corresponding data from the classic laboratory convection experiments it is shown, that for the Historic period emergence of the sunspots in the solar photosphere was strongly dominated by turbulent photospheric convection. For the Modern period, this domination was broken by a new more active dynamics of the inner layers of the convection zone. Then, it is shown that the dramatic change of the sun dynamics in the transitional period (between the Historic and Modern periods, solar cycle 1933-1944yy) had clear detectable impact on the global Earth climate at this period. Name...

  4. The IAG solar flux atlas: Accurate wavelengths and absolute convective blueshift in standard solar spectra

    E-Print Network [OSTI]

    Reiners, Ansgar; Lemke, Ulrike; Hinrichs, Johannes; Reinsch, Klaus

    2015-01-01

    We present a new solar flux atlas with the aim to understand wavelength precision and accuracy in solar benchmark data. The atlas covers the wavelength range 405--2300 nm and was observed at the Institut f\\"ur Astrophysik, G\\"ottingen (IAG) with a Fourier Transform Spectrograph. In contrast to other FTS atlases, the entire visible wavelength range was observed simultaneously using only one spectrograph setting. We compare the wavelength solution of the new atlas to the Kitt Peak solar flux atlases and to the HARPS frequency-comb calibrated solar atlas. Comparison reveals systematics in the two Kitt Peak FTS atlases resulting from their wavelength scale construction, and shows consistency between the IAG and the HARPS atlas. We conclude that the IAG atlas is precise and accurate on the order of $\\pm 10$ m s$^{-1}$ in the wavelength range 405--1065 nm while the Kitt Peak atlases show deviations as large as several ten to 100 m s$^{-1}$. We determine absolute convective blueshift across the spectrum from the IAG...

  5. Influence of baking method and baking temperature on the optical properties of ZnO thin films

    SciTech Connect (OSTI)

    Ng, Zi-Neng; Chan, Kah-Yoong

    2015-04-24

    In this work, sol-gel spin coating technique was utilised to coat ZnO thin films on glass substrates. During the intermediate 3 minutes baking process, either hotplate or convection oven was employed to bake the samples. The temperature for the baking process was varied from 150°C to 300°C for both instruments. Avantes Optical Spectrophotometer was used to characterise the optical property. The optical transmittances of hotplate-baked and oven-baked samples showed different trends with increasing baking temperatures, ranging from below 50% transmittance to over 90% transmittance in the visible range of wavelength. The difference in baking mechanisms using hotplate and convection oven will be discussed in this paper.

  6. do you know your RANGE

    E-Print Network [OSTI]

    Hoffman, Garlyn O.

    1957-01-01

    need a good knowledge of range man- asemen2 b~f~re m~kjng CID?E CD~~B~~DDS DY range plots as is required in Part 111. An ex- ample of Part I11 is on page 12. The four range plots are placed just exactly like placing a class of livestock at a stock... good cover of native grass. Grass is a product which is harvested and marketed as meat, ~uool, mohair and wildlife. When you market animals you are paid for the number of poz~nds rather than the number of head you sell. By practicing good range m...

  7. Describing the Heat Transport of Turbulent Rayleigh--B\\'enard Convection by POD methods

    E-Print Network [OSTI]

    Lülff, Johannes

    2015-01-01

    Rayleigh--B\\'enard convection, which is the buoyancy-induced motion of a fluid enclosed between two horizontal plates, is an idealised setup to study thermal convection. We analyse the modes that transport the most heat between the plates by computing the proper orthogonal decomposition (POD) of numerical data. Instead of the usual POD ansatz of finding modes that describe the energy best, we propose a method that is optimal in describing the heat transport. Thereby, we can determine the modes with the major influence on the heat transport and the coherent structures in the convection cell. We also show that in lower-dimensional projections of numerical convection data, the newly developed modes perform consistently better than the standard modes. We then use this method to analyse the main modes of three-dimensional convection in a cylindrical vessel as well as two-dimensional convection with varying Rayleigh number and varying aspect ratio.

  8. SOUND-SPEED INVERSION OF THE SUN USING A NONLOCAL STATISTICAL CONVECTION THEORY

    SciTech Connect (OSTI)

    Zhang Chunguang; Deng Licai; Xiong Darun; Christensen-Dalsgaard, Jorgen

    2012-11-01

    Helioseismic inversions reveal a major discrepancy in sound speed between the Sun and the standard solar model just below the base of the solar convection zone. We demonstrate that this discrepancy is caused by the inherent shortcomings of the local mixing-length theory adopted in the standard solar model. Using a self-consistent nonlocal convection theory, we construct an envelope model of the Sun for sound-speed inversion. Our solar model has a very smooth transition from the convective envelope to the radiative interior, and the convective energy flux changes sign crossing the boundaries of the convection zone. It shows evident improvement over the standard solar model, with a significant reduction in the discrepancy in sound speed between the Sun and local convection models.

  9. Experimental natural convection on vertical surfaces for building integrated photovoltaic (BIPV) applications

    SciTech Connect (OSTI)

    Fossa, M.; Menezo, C.; Leonardi, E.

    2008-02-15

    An experimental study on natural convection in an open channel is carried out in order to investigate the effect of the geometrical configuration of heat sources on the heat transfer behaviour. To this aim, a series of vertical heaters are cooled by natural convection of air flowing between two parallel walls. The objective of the work is to investigate the physical mechanisms which influence the thermal behaviour of a double-skin photovoltaic (PV) facade. This results in a better understanding of the related phenomena and infers useful engineering information for controlling the energy transfers from the environment to the PV surfaces and from the PV surfaces to the building. Furthermore increasing the heat transfer rate from the PV surfaces increases the conversion efficiency of the PV modules since they operate better as their temperature is lower. The test section consists in a double vertical wall, 2 m high, and each wall is constituted by 10 different heating modules 0.2 m high. The heater arrangement simulates, at a reduced scale, the presence of a series of vertical PV modules. The heat flux at the wall ranges from 75 to 200 W/m{sup 2}. In this study, the heated section is 1.6 m in height, preceded by an adiabatic of 0.4 m in height. Different heating configurations are analyzed, including the uniform heating mode and two different configurations of non uniform, alternate heating. The experimental procedure allows the wall surface temperature, local heat transfer coefficient and local and average Nusselt numbers to be inferred. The experimental evidences show that the proper selection of the separating distance and heating configuration can noticeably decrease the surface temperatures and hence enhance the conversion efficiency of PV modules. (author)

  10. Extended range chemical sensing apparatus

    DOE Patents [OSTI]

    Hughes, R.C.; Schubert, W.K.

    1994-01-18

    An apparatus is described for sensing chemicals over extended range of concentrations. In particular, first and second sensors each having separate, but overlapping ranges for sensing concentrations of hydrogen are provided. Preferably, the first sensor is a MOS solid state device wherein the metal electrode or gate is a nickel alloy. The second sensor is a chemiresistor comprising a nickel alloy. 6 figures.

  11. PACIFIC SOUTHWEST Forest and Range

    E-Print Network [OSTI]

    PACIFIC SOUTHWEST Forest and Range Experiment Station Ash Leachate Can Reduce Surface Erosion leachate can reduce surface erosion. Res. Note PSW-342, 4 p., illus. Pacific Southwest Forest and Range Exp from north- western California, ash leachate flocculated the clay frac- tions. As a result, the soil

  12. Simulation of directional solidification, thermochemical convection, and chimney formation in a Hele-Shaw cell

    E-Print Network [OSTI]

    Worster, M. Grae

    Simulation of directional solidification, thermochemical convection, and chimney formation and the Enthalpy Method throughout the computational domain allows us to avoid prescribing internal boundary

  13. The effect of shear on heat budgets in a simulated Mesoscale Convective System 

    E-Print Network [OSTI]

    Shaw, Justin David

    2000-01-01

    The evolution and structure of simulated Mesoscale Convective Systems (MCS) were examined using the Collaborative Model for Multiscale Atmospheric Simulations. Three numerical simulations were performed, with the amount ...

  14. Range Searching in Categorical Data: Colored Range Searching on Grid

    E-Print Network [OSTI]

    Agarwal, Pankaj K.

    , gsat @cs.duke.edu ¾ AT&T Labs, Shannon Laboratory, 180 Park Ave., Florham Park, NJ 07932. muthu each stock has a category that is the industry sector it belongs to, and we consider a range

  15. Water Vapor Turbulence Profiles in Stationary Continental Convective Mixed Layers

    SciTech Connect (OSTI)

    Turner, D. D.; Wulfmeyer, Volker; Berg, Larry K.; Schween, Jan

    2014-10-08

    The U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program’s Raman lidar at the ARM Southern Great Plains (SGP) site in north-central Oklahoma has collected water vapor mixing ratio (q) profile data more than 90% of the time since October 2004. Three hundred (300) cases were identified where the convective boundary layer was quasi-stationary and well-mixed for a 2-hour period, and q mean, variance, third order moment, and skewness profiles were derived from the 10-s, 75-m resolution data. These cases span the entire calendar year, and demonstrate that the q variance profiles at the mixed layer (ML) top changes seasonally, but is more related to the gradient of q across the interfacial layer. The q variance at the top of the ML shows only weak correlations (r < 0.3) with sensible heat flux, Deardorff convective velocity scale, and turbulence kinetic energy measured at the surface. The median q skewness profile is most negative at 0.85 zi, zero at approximately zi, and positive above zi, where zi is the depth of the convective ML. The spread in the q skewness profiles is smallest between 0.95 zi and zi. The q skewness at altitudes between 0.6 zi and 1.2 zi is correlated with the magnitude of the q variance at zi, with increasingly negative values of skewness observed lower down in the ML as the variance at zi increases, suggesting that in cases with larger variance at zi there is deeper penetration of the warm, dry free tropospheric air into the ML.

  16. Convection feedbacks in a super-parameterization GCM

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit the followingConcentratingPortal ControllingConvection feedbacks in a

  17. Natural convection in high heat flux tanks at the Hanford Waste Site / [by] Mark van der Helm and Mujid S. Kazimi

    E-Print Network [OSTI]

    Van der Helm, Mark Johan, 1972-

    1996-01-01

    A study was carried out on the potential for natural convection and the effect of natural convection in a High Heat Flux Tank, Tank 241-C-106, at the Hanford Reservation. To determine the existence of natural convection, ...

  18. The Mechanism of First Raindrops Formation in Deep Convective Clouds

    SciTech Connect (OSTI)

    Khain, Alexander; Prabha, Thara; Benmoshe, Nir; Pandithurai, G.; Ovchinnikov, Mikhail

    2013-08-22

    The formation of first raindrops in deep convective clouds is investigated. A combination of observational data analysis and 2-D and 3-D numerical bin microphysical simulations of deep convective clouds suggests that the first raindrops form at the top of undiluted or slightly diluted cores. It is shown that droplet size distributions in these regions are wider and contain more large droplets than in diluted volumes. The results of the study indicate that the initial raindrop formation is determined by the basic microphysical processes within ascending adiabatic volumes. It allows one to predict the height of the formation of first raindrops considering the processes of nucleation, diffusion growth and collisions. The results obtained in the study explain observational results reported by Freud and Rosenfeld (2012) according to which the height of first raindrop formation depends linearly on the droplet number concentration at cloud base. The results also explain why a simple adiabatic parcel model can reproduce this dependence. The present study provides a physical basis for retrieval algorithms of cloud microphysical properties and aerosol properties using satellites proposed by Rosenfeld et al. ( 2012). The study indicates that the role of mixing and entrainment in the formation of the first raindrops is not of crucial importance. It is also shown that low variability of effective and mean volume radii along horizontal traverses, as regularly observed by in situ measurements, can be simulated by high-resolution cloud models, in which mixing is parameterized by a traditional 1.5 order turbulence closure scheme.

  19. The annual cycle in equatorial convection and sea surface temperature

    SciTech Connect (OSTI)

    Mitchell, T.P.; Wallace, J.M. (Washington Univ., Seattle (United States) NASA, Goddard Space Flight Center, Greenbelt, MD (United States))

    1992-10-01

    The coupled atmosphere-ocean system in the equatorial eastern Pacific and Atlantic exhibits a distinct annual cycle that is reflected in contrasting conditions at the times of the two equinoxes. The contrasts are so strong that they dominate the annual march of zonally averaged outgoing long wave radiation for the equatorial belt. The March equinox corresponds to the warm season when the equatorial cold tongues in the eastern Pacific and Atlantic area absent. With the onset of summer monsoon convection over Colombia, Central America, and West Africa in May-June, northward surface winds strengthen over the eastern Pacific and Atlantic, the equatorial cold tongues reappear, and the marine convection shifts from the equatorial belt to the intertropical convergence zones (ITCZs) along 8 deg N. On the basis of observational evidence concerning the timing and year-to-year regularity of the surface wind changes during the development of the cold tongues, it is argued that (1) the increase in the northward surface winds in response to the onset of the northern summer monsoon may be instrumental in reestablishing the cold tongues, and (2) positive feedbacks involving both the zonal and meridional wind components contribute to the remarkable robustness of the cold tongue-ITCZs complexes in both oceans. 36 refs.

  20. ARM - Midlatitude Continental Convective Clouds (jensen-sonde)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Mike; Comstock, Jennifer; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    A major component of the Mid-latitude Continental Convective Clouds Experiment (MC3E) field campaign was the deployment of an enhanced radiosonde array designed to capture the vertical profile of atmospheric state variables (pressure, temperature, humidity wind speed and wind direction) for the purpose of deriving the large-scale forcing for use in modeling studies. The radiosonde array included six sites (enhanced Central Facility [CF-1] plus five new sites) launching radiosondes at 3-6 hour sampling intervals. The network will cover an area of approximately (300)2 km2 with five outer sounding launch sites and one central launch location. The five outer sounding launch sites are: S01 Pratt, KS [ 37.7oN, 98.75oW]; S02 Chanute, KS [37.674, 95.488]; S03 Vici, Oklahoma [36.071, -99.204]; S04 Morris, Oklahoma [35.687, -95.856]; and S05 Purcell, Oklahoma [34.985, -97.522]. Soundings from the SGP Central Facility during MC3E can be retrieved from the regular ARM archive. During routine MC3E operations 4 radiosondes were launched from each of these sites (approx. 0130, 0730, 1330 and 1930 UTC). On days that were forecast to be convective up to four additional launches were launched at each site (approx. 0430, 1030, 1630, 2230 UTC). There were a total of approximately 14 of these high frequency launch days over the course of the experiment.

  1. ARM - Midlatitude Continental Convective Clouds (jensen-sonde)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Mike; Comstock, Jennifer; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    2012-01-19

    A major component of the Mid-latitude Continental Convective Clouds Experiment (MC3E) field campaign was the deployment of an enhanced radiosonde array designed to capture the vertical profile of atmospheric state variables (pressure, temperature, humidity wind speed and wind direction) for the purpose of deriving the large-scale forcing for use in modeling studies. The radiosonde array included six sites (enhanced Central Facility [CF-1] plus five new sites) launching radiosondes at 3-6 hour sampling intervals. The network will cover an area of approximately (300)2 km2 with five outer sounding launch sites and one central launch location. The five outer sounding launch sites are: S01 Pratt, KS [ 37.7oN, 98.75oW]; S02 Chanute, KS [37.674, 95.488]; S03 Vici, Oklahoma [36.071, -99.204]; S04 Morris, Oklahoma [35.687, -95.856]; and S05 Purcell, Oklahoma [34.985, -97.522]. Soundings from the SGP Central Facility during MC3E can be retrieved from the regular ARM archive. During routine MC3E operations 4 radiosondes were launched from each of these sites (approx. 0130, 0730, 1330 and 1930 UTC). On days that were forecast to be convective up to four additional launches were launched at each site (approx. 0430, 1030, 1630, 2230 UTC). There were a total of approximately 14 of these high frequency launch days over the course of the experiment.

  2. An observational study of entrainment rate in deep convection

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Guo, Xiaohao; Lu, Chunsong; Zhao, Tianliang; Zhang, Guang Jun; Liu, Yangang

    2015-09-22

    This study estimates entrainment rate and investigates its relationships with cloud properties in 156 deep convective clouds based on in-situ aircraft observations during the TOGA-COARE (Tropical Ocean Global Atmosphere Coupled Ocean Atmosphere Response Experiment) field campaign over the western Pacific. To the authors’ knowledge, this is the first study on the probability density function of entrainment rate, the relationships between entrainment rate and cloud microphysics, and the effects of dry air sources on the calculated entrainment rate in deep convection from an observational perspective. Results show that the probability density function of entrainment rate can be well fitted by lognormal,more »gamma or Weibull distribution, with coefficients of determination being 0.82, 0.85 and 0.80, respectively. Entrainment tends to reduce temperature, water vapor content and moist static energy in cloud due to evaporative cooling and dilution. Inspection of the relationships between entrainment rate and microphysical properties reveals a negative correlation between volume-mean radius and entrainment rate, suggesting the potential dominance of homogeneous mechanism in the clouds examined. The entrainment rate and environmental water vapor content show similar tendencies of variation with the distance of the assumed environmental air to the cloud edges. Their variation tendencies are non-monotonic due to the relatively short distance between adjacent clouds.« less

  3. Observations of prolific transient luminous event production above a mesoscale convective system in Argentina during

    E-Print Network [OSTI]

    Cummer, Steven A.

    in Argentina during the Sprite2006 Campaign in Brazil F. T. São Sabbas,1 M. J. Taylor,2 P.D. Pautet,2 M. Bailey convective system (MCS) over Argentina, as part of the third sprite campaign in Brazil. GOES infrared (IR a mesoscale convective system in Argentina during the Sprite2006 Campaign in Brazil, J. Geophys. Res., 115, A

  4. A Fourier-spectral element algorithm for thermal convection in rotating axisymmetric containers

    E-Print Network [OSTI]

    Fournier, Alexandre

    A Fourier-spectral element algorithm for thermal convection in rotating axisymmetric containers Abstract We present a Fourier-spectral element approach for modeling thermal convection in a rotating, Spectral Methods for Axisymmetric Domains, Gauthier-Villars, Paris, 1999], a Fourier expansion of the field

  5. Simulation of Convection and Macrosegregation in Steel Casting C. Beckermann* and M. C. Schneider**

    E-Print Network [OSTI]

    Beckermann, Christoph

    Simulation of Convection and Macrosegregation in Steel Casting C. Beckermann* and M. C. Schneider.C., "Simulation of Convection and Macrosegregation in Steel Casting," in Proceedings of the 50th SFSA Technical and the mushy zone. This is particularly true in heavy steel castings which have very large cross sections

  6. Global warming, convective threshold and false thermostats Ian N. Williams,1

    E-Print Network [OSTI]

    Global warming, convective threshold and false thermostats Ian N. Williams,1 Raymond T thermostats. Citation: Williams, I. N., R. T. Pierrehumbert, and M. Huber (2009), Global warming, convective. To first order this consists of a shift to warmer temperatures as climate warms, without change of shape

  7. The influence of the transition zone water filter on convective circulation in the mantle

    E-Print Network [OSTI]

    The influence of the transition zone water filter on convective circulation in the mantle Garrett M 2004. [1] The ``transition zone water filter'' model of mantle convection attempts to reconcile bulk mass and heat transfer across mantle interfaces. Here we test the basic effect of the water filter

  8. A STRONGLY DEGENERATE CONVECTION-DIFFUSION PROBLEM MODELING CENTRIFUGATION OF FLOCCULATED SUSPENSIONS

    E-Print Network [OSTI]

    A STRONGLY DEGENERATE CONVECTION-DIFFUSION PROBLEM MODELING CENTRIFUGATION OF FLOCCULATED of BV entropy solutions of a strongly degenerate convection-di#11;usion problem modeling centrifugation- boundary value problem numerically, i.e., to simulate the centrifugation process. 1. Introduction We

  9. Evidence that solar wind fluctuations substantially affect global convection and substorm occurrence

    E-Print Network [OSTI]

    California at Berkeley, University of

    that this implies that solar wind ULF power may be an important contributor to the strength of coupling of solar for the connection between iono- spheric convection and solar wind ULF power. The high correlations between ULF powerEvidence that solar wind fluctuations substantially affect global convection and substorm

  10. Influences of Precipitation on Water Mass Transformation and Deep Convection MICHAEL A. SPALL

    E-Print Network [OSTI]

    Influences of Precipitation on Water Mass Transformation and Deep Convection MICHAEL A. SPALL for the temperature and salinity anomalies of deep convective water masses, making explicit their dependence on both on water mass transformation and the strength of the meridional over- turning circulation in marginal seas

  11. Adaptive Thermal Management for Portable System Batteries by Forced Convection Cooling

    E-Print Network [OSTI]

    Pedram, Massoud

    Adaptive Thermal Management for Portable System Batteries by Forced Convection Cooling Qing Xie a portable system. Since the cooling fan is also powered by the same battery, it is critical to develop thermal management problem for batteries (ATMB) in the portable systems with forced convection cooling

  12. A Climatology of Midlatitude Mesoscale Convective Vortices in the Rapid Update Cycle

    E-Print Network [OSTI]

    Johnson, Richard H.

    A Climatology of Midlatitude Mesoscale Convective Vortices in the Rapid Update Cycle ERIC P. JAMES of mesoscale convective vortices (MCVs) occurring in the state of Oklahoma during the late spring and summer, true MCVs represent only about 20% of the mesoscale relative vorticity maxima detected by the algorithm

  13. Some Effects of Model Resolution on Simulated Gravity Waves Generated by Deep, Mesoscale Convection

    E-Print Network [OSTI]

    Knievel, Jason Clark

    Some Effects of Model Resolution on Simulated Gravity Waves Generated by Deep, Mesoscale Convection. Introduction Gravity waves generated by deep convective clouds play an important role in the momentum budget scales: short gravity waves generated by individual con- vective systems and cells on the meso- and meso

  14. Hydrodynamical simulations of penetrative convection and generation of internal gravity waves

    E-Print Network [OSTI]

    Stêpieñ, Kazimierz

    Hydrodynamical simulations of penetrative convection and generation of internal gravity waves M investigate the generation of internal gravity waves in the stable region below a convective layer by means of angular momentum from the place where the waves are generated to the region of their dissipation, which

  15. Improving Convection Parameterization Using ARM Observations and NCAR Community Atmosphere Model

    SciTech Connect (OSTI)

    Zhang, Guang J [Scripps Institution of Oceanography

    2013-07-29

    Highlight of Accomplishments: We made significant contribution to the ASR program in this funding cycle by better representing convective processes in GCMs based on knowledge gained from analysis of ARM/ASR observations. In addition, our work led to a much improved understanding of the interaction among aerosol, convection, clouds and climate in GCMs.

  16. THE MAGNETIC CONNECTION BETWEEN THE CONVECTION ZONE AND CORONA IN THE QUIET SUN

    E-Print Network [OSTI]

    Abbett, Bill

    THE MAGNETIC CONNECTION BETWEEN THE CONVECTION ZONE AND CORONA IN THE QUIET SUN W. P. Abbett Space connection between the convectively unstable layers below the visible surface of the Sun and the overlying application of this numerical model, we present a series of simulations of the quiet Sun in a domain

  17. Resolving Convection in a Global Hypohydrostatic Model by S. T. Garner1

    E-Print Network [OSTI]

    Vallis, Geoff

    -resolution, nonhydrostatic model free of convective parameterization, and describe the effect on the global climate of very that the huge scale separation creates for numerical climate modeling might be safely removed by effectivelyResolving Convection in a Global Hypohydrostatic Model by S. T. Garner1 , D. M. W. Frierson2 , I. M

  18. PARAMETERS OF THE SOLAR CONVECTION ZONE IN EVOLUTIONARY AND SEISMIC MODELS

    E-Print Network [OSTI]

    PARAMETERS OF THE SOLAR CONVECTION ZONE IN EVOLUTIONARY AND SEISMIC MODELS VLADIMIR A. BATURIN defines (T \\Gammaae) profile of the adiabatic convection zone, but together with surface conditions of the helium ionization zone (with type of EOS as labels). Filled square with a vertical error bar

  19. Environment and the Lifetime of Tropical Deep Convection in a Cloud-Permitting Regional Model Simulation

    SciTech Connect (OSTI)

    Hagos, Samson M.; Feng, Zhe; McFarlane, Sally A.; Leung, Lai-Yung R.

    2013-08-01

    By applying a cloud tracking algorithm to tropical convective systems simulated by a regional high resolution model, the study documents environmental conditions before and after convective systems are initiated over ocean and land by following them during their lifetime. The comparative roles of various environmental fields in affecting the lifetime of convection are also quantified. The statistics of lifetime, maximum area, propagation speed and direction of the simulated deep convection agrees well with geostationary satellite observations. Over ocean, convective systems enhance surface fluxes through the associated wind gusts as well as cooling and drying of the boundary layer. A significant relationship is found between the mean surface fluxes during their lifetime and the longevity of the systems which in turn is related to the initial intensity of the moist updraft and to a lesser extent upper level shear. Over land, on the other hand, convective activity suppresses surface fluxes through cloud cover and the lifetime of convection is related to the upper level shear during their lifetime and strength of the heat fluxes several hours before the initiation of convection. For systems of equal lifetime, those over land are significantly more intense than those over ocean especially during early stages of their lifetime.

  20. Aerosol control on depth of warm rain in convective clouds Mahen Konwar,1

    E-Print Network [OSTI]

    Daniel, Rosenfeld

    Aerosol control on depth of warm rain in convective clouds Mahen Konwar,1 R. S. Maheskumar,1 J. R effective radius (re) increased with distance above cloud base (D). Warm rain became detectable, i.e., rain water content >0.01 g/Kg, at the tops of growing convective clouds when re exceeded 12 mm. The re

  1. 8D.3 INVESTIGATING CONVECTIVE ELEMENTS IN A HIGH RESOLUTION SIMULATION OF HURRICANE OPAL (1995)

    E-Print Network [OSTI]

    Wilhelmson, Robert

    1995-01-01

    8D.3 INVESTIGATING CONVECTIVE ELEMENTS IN A HIGH RESOLUTION SIMULATION OF HURRICANE OPAL (1995. INTRODUCTION Numerous studies have investigated the intensity and track of Hurricane Opal in 1995, an event the convective scale behavior of the hurricane. This is of particular interest because Hurricane Opal

  2. Convective heat transfer as a function of wavelength: Implications for the cooling of the Earth

    E-Print Network [OSTI]

    Convective heat transfer as a function of wavelength: Implications for the cooling of the Earth C, in particular, on its variation with the wavelength of convection. The heat transfer strongly depends in Earth's mantle can significantly reduce the efficiency of heat transfer. The likely variations

  3. HEAT TRANSFERS IN A DOUBLE SKIN ROOF VENTILATED BY NATURAL CONVECTION IN SUMMER TIME

    E-Print Network [OSTI]

    Boyer, Edmond

    1 HEAT TRANSFERS IN A DOUBLE SKIN ROOF VENTILATED BY NATURAL CONVECTION IN SUMMER TIME P. H or in tropical and arid countries. In this work, radiation, convection and conduction heat transfers-dimensional numerical simulation of the heat transfers through the double skin reveals the most important parameters

  4. The effect of increased convective entrainment on Asian monsoon biases in

    E-Print Network [OSTI]

    Wirosoetisno, Djoko

    The effect of increased convective entrainment on Asian monsoon biases in the MetUM General entrainment on Asian monsoon biases in the MetUM General Circulation Model. Quarterly Journal of the Royal Reading's research outputs online #12;AcceptedArticle The effect of increased convective entrainment

  5. Numerical model of mixed convection heat transfer between a series of vertical parallel plates with planar heat sources 

    E-Print Network [OSTI]

    Watson, James Christopher

    1995-01-01

    generating surfaces was accomplished by laminar mixed convection, in which forced and free convection effects were considered, and conjugate conduction through the plate. The forced flow at the channel inlet was assumed to be that of an upward flowing...

  6. Measurements of ionospheric electric field convection by the long-line technique

    SciTech Connect (OSTI)

    MacDougall, J.W.

    1981-06-01

    Ionospheric E x B convections are measured by a new technique that uses satellite scintillations. The measurements are for and ionospheric region centred on 39/sup 0/N, 82/sup 0/W geographic or 53/sup 0/ invarient latitude. Results are presented for spring equinox 1980. The quiet condition eastward convection drift is approximately V/sub i/E = -12+43 cos(2..pi../24)(t-13.4). During disturbed conditions at nighttime the westward convection becomes large and highly variable. The northward perpendicular E x B convection is approximately V/sub i/N = -5+13 cos (2..pi../12)(t-10.5)+6 cos (2..pi../24) (t-11.5) m/s during quiet conditions. During disturbed conditions the semidiurnal component of the northward convection increases by about a factor of 3 and becomes larger than the diurnal.

  7. An Experimental Study of Enhanced Thermal Conductivity Utilizing Columnated Silicon Microevaporators for Convective Boiling Heat Transfer at the Microscale

    E-Print Network [OSTI]

    Hogue, Christopher William

    2011-01-01

    topic, and researchers all over the world began reworking classical convection correlations to better model heat transfer

  8. Limitation of parallel flow in double diffusive convection: Two- and three-dimensional transitions in a horizontal porous domain

    SciTech Connect (OSTI)

    Mimouni, N.; Chikh, S.; Rahli, O.; Bennacer, R.

    2014-07-15

    Two-dimensional (2D) and three-dimensional (3D) numerical simulations of double diffusion natural convection in an elongated enclosure filled with a binary fluid saturating a porous medium are carried out in the present work. The Boussinesq approximation is made in the formulation of the problem, and Neumann boundary conditions for temperature and concentration are adopted, respectively, on vertical and horizontal walls of the cavity. The used numerical method is based on the control volume approach, with the third order quadratic upstream interpolation scheme in approximating the advection terms. A semi implicit method algorithm is used to handle the velocity-pressure coupling. To avoid the excessively high computer time inherent to the solution of 3D natural convection problems, full approximation storage with full multigrid method is used to solve the problem. A wide range of the controlling parameters (Rayleigh-Darcy number Ra, lateral aspect ratio Ay, Lewis number Le, and the buoyancy ration N) is investigated. We clearly show that increasing the depth of the cavity (i.e., the lateral aspect ratio) has an important effect on the flow patterns. The 2D perfect parallel flows obtained for small lateral aspect ratio are drastically destabilized by increasing the cavity lateral dimension. This yields a 3D fluid motion with a much more complex flow pattern and the usually considered 2D parallel flow model cannot be applied.

  9. PACIFIC SOUTHWEST Forest and Range

    E-Print Network [OSTI]

    of forest stands is valuable for studies of the physical environment. Energy balance research centers on howPACIFIC SOUTHWEST Forest and Range Experiment Station FOREST SERVICE U.S. DEPARTMENT in relation to climatic and stand variables USDA FOREST SERVICE RESEARCH PAPER PSW- 71 /1971 #12;CONTENTS

  10. Forest and Range Experiment Station

    E-Print Network [OSTI]

    wider range of suppliers. As working circles beyond the size of a single National Forest have recently. Alternatives for expansion of working circles must be assessed in light of present Forest Service timber management policy and the impacts of timber supply. These alternates include (a) combination of National

  11. A Family of Fourth Order Difference Schemes on Rotated Grid for Two Dimensional ConvectionDiffusion Equation \\Lambda

    E-Print Network [OSTI]

    Zhang, Jun

    A Family of Fourth Order Difference Schemes on Rotated Grid for Two Dimensional Convection a family of fourth order finite difference schemes on the rotated grid for the two dimensional convection values of the convection coefficients. We also compare the fourth order schemes with the nine point

  12. OPTIMAL CONTROL OF THERMALLY CONVECTED FLUID FLOWS \\Lambda K. ITO y AND S.S. RAVINDRAN y

    E-Print Network [OSTI]

    OPTIMAL CONTROL OF THERMALLY CONVECTED FLUID FLOWS \\Lambda K. ITO y AND S.S. RAVINDRAN y Abstract. We examine the optimal control of stationary thermally convected fluid flows from the the­ oretical and numerical point of view. We use thermal convection as control mechanism, that is, control is effected

  13. Charge transfer and in-cloud structure of large-charge-moment positive lightning strokes in a mesoscale convective system

    E-Print Network [OSTI]

    Cummer, Steven A.

    in a mesoscale convective system Gaopeng Lu,1 Steven A. Cummer,1 Jingbo Li,1 Feng Han,1 Richard J. Blakeslee,2 positive cloud-to-ground (+CG) strokes in a mesoscale convective system. Although no high altitude images of large-charge-moment positive lightning strokes in a mesoscale convective system, Geophys. Res. Lett., 36

  14. The structure and dynamics of patterns of Benard convection cells

    SciTech Connect (OSTI)

    Rivier, N. Imperial Coll. of Science and Technology, London . Blackett Lab. Lausanne Univ. . Inst. de Physique Experimentale)

    1990-08-01

    Benard-Marangoni convection, in containers with large aspect ratio, exhibits space-filling cellular structures, highly deformable, but crystallized. They contain dislocations and grain boundaries generated and moved by elementary topological transformations, and are subjected to a weak shear stress due to the earth's rotation. The cellular structure and its fluctuations are analyzed from a crystallographic viewpoint, by using two complementary approaches. One is a global analysis of cellular structures in cylindrical symmetry. Their structural stability and defect pattern are obtained as topological mode-locking of a continuous structural parameter. The other, a local, molecular dynamics of the cells, gives a realistic parametrization of the forces and the transformations by generalizing the Voronoi cell construction in one extra dimension. 23 refs., 8 figs.

  15. Simultaneous temperature and velocity Lagrangian measurements in turbulent thermal convection

    E-Print Network [OSTI]

    Liot, O; Zonta, F; Chibbaro, S; Coudarchet, T; Gasteuil, Y; Pinton, J -F; Salort, J; Chillà, F

    2015-01-01

    We report joint Lagrangian velocity and temperature measurements in turbulent thermal convection. Measurements are performed using an improved version (extended autonomy) of the neutrally-buoyant instrumented particle that was used by to performed experiments in a parallelepipedic Rayleigh-Benard cell. The temperature signal is obtained from a RFtransmitter. Simultaneously, we determine particle's position and velocity with one camera, which grants access to the Lagrangian heat flux. Due to the extended autonomy of the present particle, we obtain well converged temperature and velocity statistics, as well as pseudo-eulerian maps of velocity and heat flux. Present experimental results have also been compared with the results obtained by a corresponding campaign of Direct Numerical Simulations and Lagrangian Tracking of massless tracers. The comparison between experimental and numerical results show the accuracy and reliability of our experimental measurements. Finally, the analysis of lagrangian velocity and t...

  16. Range determination for scannerless imaging

    DOE Patents [OSTI]

    Muguira, Maritza Rosa (Albuquerque, NM); Sackos, John Theodore (Albuquerque, NM); Bradley, Bart Davis (Albuquerque, NM); Nellums, Robert (Albuquerque, NM)

    2000-01-01

    A new method of operating a scannerless range imaging system (e.g., a scannerless laser radar) has been developed. This method is designed to compensate for nonlinear effects which appear in many real-world components. The system operates by determining the phase shift of the laser modulation, which is a physical quantity related physically to the path length between the laser source and the detector, for each pixel of an image.

  17. Range gated strip proximity sensor

    DOE Patents [OSTI]

    McEwan, Thomas E. (Livermore, CA)

    1996-01-01

    A range gated strip proximity sensor uses one set of sensor electronics and a distributed antenna or strip which extends along the perimeter to be sensed. A micro-power RF transmitter is coupled to the first end of the strip and transmits a sequence of RF pulses on the strip to produce a sensor field along the strip. A receiver is coupled to the second end of the strip, and generates a field reference signal in response to the sequence of pulse on the line combined with received electromagnetic energy from reflections in the field. The sensor signals comprise pulses of radio frequency signals having a duration of less than 10 nanoseconds, and a pulse repetition rate on the order of 1 to 10 MegaHertz or less. The duration of the radio frequency pulses is adjusted to control the range of the sensor. An RF detector feeds a filter capacitor in response to received pulses on the strip line to produce a field reference signal representing the average amplitude of the received pulses. When a received pulse is mixed with a received echo, the mixing causes a fluctuation in the amplitude of the field reference signal, providing a range-limited Doppler type signature of a field disturbance.

  18. Range gated strip proximity sensor

    DOE Patents [OSTI]

    McEwan, T.E.

    1996-12-03

    A range gated strip proximity sensor uses one set of sensor electronics and a distributed antenna or strip which extends along the perimeter to be sensed. A micro-power RF transmitter is coupled to the first end of the strip and transmits a sequence of RF pulses on the strip to produce a sensor field along the strip. A receiver is coupled to the second end of the strip, and generates a field reference signal in response to the sequence of pulse on the line combined with received electromagnetic energy from reflections in the field. The sensor signals comprise pulses of radio frequency signals having a duration of less than 10 nanoseconds, and a pulse repetition rate on the order of 1 to 10 MegaHertz or less. The duration of the radio frequency pulses is adjusted to control the range of the sensor. An RF detector feeds a filter capacitor in response to received pulses on the strip line to produce a field reference signal representing the average amplitude of the received pulses. When a received pulse is mixed with a received echo, the mixing causes a fluctuation in the amplitude of the field reference signal, providing a range-limited Doppler type signature of a field disturbance. 6 figs.

  19. Regressed relations for forced convection heat transfer in a direct injection stratified charge rotary engine

    SciTech Connect (OSTI)

    Lee, C.M.; Schock, H.J.

    1988-01-01

    Currently, the heat transfer equation used in the rotary combustion engine (RCE) simulation model is taken from piston engine studies. These relations have been empirically developed by the experimental input coming from piston engines whose geometry differs considerably from that of the RCE. The objective of this work was to derive equations to estimate heat transfer coefficients in the combustion chamber of an RCE. This was accomplished by making detailed temperature and pressure measurements in a direct injection stratified charge (DISC) RCE under a range of conditions. For each specific measurement point, the local gas velocity was assumed equal to the local rotor tip speed. Local physical properties of the fluids were then calculated. Two types of correlation equations were derived and are described in this paper. The first correlation expresses the Nusselt number as a function of the Prandtl number, Reynolds number, and characteristic temperature ratio; the second correlation expresses the forced convection heat transfer coefficient as a function of fluid temperature, pressure and velocity. 10 references.

  20. Interactions between cumulus convection and its environment as revealed by the MC3E sounding array

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Xie, Shaocheng; Zhang, Yunyan; Giangrande, Scott E.; Jensen, Michael P.; McCoy, Renata; Zhang, Minghua

    2014-10-27

    This study attempts to understand interactions between midlatitude convective systems and their environments through a heat and moisture budget analysis using the sounding data collected from the Midlatitude Continental Convective Clouds Experiment (MC3E) in central Oklahoma. Distinct large-scale structures and diabatic heating and drying profiles are presented for cases of weaker and elevated thunderstorms as well as intense squall line and supercell thunderstorm events during the campaign. The elevated cell events were nocturnal convective systems occurring in an environment having low convective available potential energy (CAPE) and a very dry boundary layer. In contrast, deeper convective events happened during themore »morning into early afternoon within an environment associated with large CAPE and a near-saturated boundary layer. As the systems reached maturity, the diagnosed diabatic heating in the latter deep convective cases was much stronger and of greater vertical extent than the former. Both groups showed considerable diabatic cooling in the lower troposphere, associated with the evaporation of precipitation and low-level clouds. The horizontal advection of moisture also played a dominant role in moistening the lower troposphere, particularly for the deeper convective events, wherein the near surface southeasterly flow allows persistent low-level moisture return from the Gulf of Mexico to support convection. The moisture convergence often was present before these systems develop, suggesting a strong correlation between the large-scale moisture convergence and convection. As a result, sensitivity tests indicated that the uncertainty in the surface precipitation and the size of analysis domain mainly affected the magnitude of these analyzed fields rather than their vertical structures.« less

  1. Interactions between Cumulus Convection and Its Environment as Revealed by the MC3E Sounding Array

    SciTech Connect (OSTI)

    Xie, Shaocheng [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Jensen, Michael P. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Zhang, Yunyan [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Giangrande, Scott E. [Brookhaven National Laboratory (BNL), Upton, NY (United States); McCoy, Renata [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Zhang, Minghua [Stony Brook Univ., Stony Brook, NY (United States)

    2014-10-27

    This study attempts to understand interactions between midlatitude convective systems and their environments through a heat and moisture budget analysis using the sounding data collected from the Midlatitude Continental Convective Clouds Experiment (MC3E) in central Oklahoma. Distinct large-scale structures and diabatic heating and drying profiles are presented for cases of weaker and elevated thunderstorms as well as intense squall line and supercell thunderstorm events during the campaign. The elevated cell events were nocturnal convective systems occurring in an environment having low convective available potential energy (CAPE) and a very dry boundary layer. In contrast, deeper convective events happened during the morning into early afternoon within an environment associated with large CAPE and a near-saturated boundary layer. As the systems reached maturity, the diagnosed diabatic heating in the latter deep convective cases was much stronger and of greater vertical extent than the former. Both groups showed considerable diabatic cooling in the lower troposphere, associated with the evaporation of precipitation and low-level clouds. The horizontal advection of moisture also played a dominant role in moistening the lower troposphere, particularly for the deeper convective events, wherein the near surface southeasterly flow allows persistent low-level moisture return from the Gulf of Mexico to support convection. The moisture convergence often was present before these systems develop, suggesting a strong correlation between the large-scale moisture convergence and convection. Sensitivity tests indicated that the uncertainty in the surface precipitation and the size of analysis domain mainly affected the magnitude of these analyzed fields rather than their vertical structures.

  2. MODELING HEAT TRANSFER IN SPENT FUEL TRANSFER CASK NEUTRON SHIELDS – A CHALLENGING PROBLEM IN NATURAL CONVECTION

    SciTech Connect (OSTI)

    Fort, James A.; Cuta, Judith M.; Bajwa, C.; Baglietto, E.

    2010-07-18

    In the United States, commercial spent nuclear fuel is typically moved from spent fuel pools to outdoor dry storage pads within a transfer cask system that provides radiation shielding to protect personnel and the surrounding environment. The transfer casks are cylindrical steel enclosures with integral gamma and neutron radiation shields. Since the transfer cask system must be passively cooled, decay heat removal from spent nuclear fuel canister is limited by the rate of heat transfer through the cask components, and natural convection from the transfer cask surface. The primary mode of heat transfer within the transfer cask system is conduction, but some cask designs incorporate a liquid neutron shield tank surrounding the transfer cask structural shell. In these systems, accurate prediction of natural convection within the neutron shield tank is an important part of assessing the overall thermal performance of the transfer cask system. The large-scale geometry of the neutron shield tank, which is typically an annulus approximately 2 meters in diameter but only 10-15 cm in thickness, and the relatively small scale velocities (typically less than 5 cm/s) represent a wide range of spatial and temporal scales that contribute to making this a challenging problem for computational fluid dynamics (CFD) modeling. Relevant experimental data at these scales are not available in the literature, but some recent modeling studies offer insights into numerical issues and solutions; however, the geometries in these studies, and for the experimental data in the literature at smaller scales, all have large annular gaps that are not prototypic of the transfer cask neutron shield. This paper proposes that there may be reliable CFD approaches to the transfer cask problem, specifically coupled steady-state solvers or unsteady simulations; however, both of these solutions take significant computational effort. Segregated (uncoupled) steady state solvers that were tested did not accurately capture the flow field and heat transfer distribution in this application. Mesh resolution, turbulence modeling, and the tradeoff between steady state and transient solutions are addressed. Because of the critical nature of this application, the need for new experiments at representative scales is clearly demonstrated.

  3. Mesoscale flows in large aspect ratio simulations of turbulent compressible convection

    E-Print Network [OSTI]

    F. Rincon; F. Lignieres; M. Rieutord

    2006-11-28

    We present the results of a very large aspect ratio (42.6) numerical simulation of fully compressible turbulent convection in a polytropic atmosphere, and focus on the properties of large-scale flows. Mesoscale patterns dominate the turbulent energy spectrum. We show that these structures, which had already been observed in Boussinesq simulations by Cattaneo et al. (2001), have a genuine convective origin and do not result directly from collective interactions of the smaller scales of the flow, even though their growth is strongly affected by nonlinear transfers. If this result is relevant to the solar photosphere, it suggests that the dominant convective mode below the Sun's surface may be at mesoscales.

  4. Extended-range tiltable micromirror

    DOE Patents [OSTI]

    Allen, James J. (Albuquerque, NM); Wiens, Gloria J. (Newberry, FL); Bronson, Jessica R. (Gainesville, FL)

    2009-05-05

    A tiltable micromirror device is disclosed in which a micromirror is suspended by a progressive linkage with an electrostatic actuator (e.g. a vertical comb actuator or a capacitive plate electrostatic actuator) being located beneath the micromirror. The progressive linkage includes a pair of torsion springs which are connected together to operate similar to a four-bar linkage with spring joints. The progressive linkage provides a non-linear spring constant which can allow the micromirror to be tilted at any angle within its range substantially free from any electrostatic instability or hysteretic behavior.

  5. Range Fuels | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoop Inc Jump to:Newberg,Energy LLCALLETEREFU Elektronik GmbHRahusRamkyRange Fuels Jump

  6. Range Resources | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION JEnvironmental Jump to:EA EIS Report UrlNM-b < RAPID‎Wind Farm Jump to:Randsburg,Range

  7. Live Fire Range Environmental Assessment

    SciTech Connect (OSTI)

    1993-08-01

    The Central Training Academy (CTA) is a DOE Headquarters Organization located in Albuquerque, New Mexico, with the mission to effectively and efficiently educate and train personnel involved in the protection of vital national security interests of DOE. The CTA Live Fire Range (LFR), where most of the firearms and tactical training occurs, is a complex separate from the main campus. The purpose of the proposed action is to expand the LFR to allow more options of implementing required training. The Department of Energy has prepared this Environmental Assessment (EA) for the proposed construction and operation of an expanded Live Fire Range Facility at the Central Training Academy in Albuquerque, New Mexico. Based on the analysis in the EA, DOE has determined 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 (NEPA) of 1969. Therefore, the preparation of an environmental impact statement is not required and DOE is issuing this Finding of No Significant Impact (FONSI).

  8. Modeling Free Convection Flow of Liquid Hydrogen within a Cylindrical Heat Exchanger Cooled to 14 K

    E-Print Network [OSTI]

    Yang, S.W.; Oxford U.

    2004-01-01

    M. A. , “Comments on Liquid Hydrogen Absorbers for MICE,”Gas at 14 to 18 K and Liquid Hydrogen at 20 K circulated byFREE CONVECTION FLOW OF LIQUID HYDROGEN WITHIN A CYLINDRICAL

  9. Characteristics of convective cells over the coastal regions of southeast Texas 

    E-Print Network [OSTI]

    Robinson, Michael

    1998-01-01

    Vertical profiles of radar reflectivity and cloud-to-ground lightning characteristics associated with convective cells were analyzed for mesoscate systems occurring over the coastal regions of southeast Texas during the ...

  10. Turbulent convection in the anelastic rotating sphere : a model for the circulation on the giant planets

    E-Print Network [OSTI]

    Kaspi, Yohai

    2008-01-01

    This thesis studies the dynamics of a rotating compressible gas sphere, driven by internal convection, as a model for the dynamics on the giant planets. We develop a new general circulation model for the Jovian atmosphere, ...

  11. A case study of the low-level jet during an episode of spring convection 

    E-Print Network [OSTI]

    Donahoe, Christopher Scott

    1996-01-01

    Circulation and transport of the low-level jet (LLJ) were examined for a case of severe convection that occurred in Spring 1995. Radiosonde observations and Eta model output on constant pressure and isentropic surfaces allowed a detailed examination...

  12. The feasibility of thermal and compositional convection in Earth’s inner core

    E-Print Network [OSTI]

    Lythgoe, Karen H.; Rudge, John F.; Neufeld, Jerome A.; Deuss, Arwen

    2015-03-12

    of a large core thermal conductivity result in stable thermal stratification, hindering convection. However, an unstable density stratification may arise due to the pressure dependant partition coefficient of certain light elements. We show...

  13. Experimental Investigation of Forced Convection Heat Transfer of Nanofluids in a Microchannel using Temperature Nanosensors 

    E-Print Network [OSTI]

    Yu, Jiwon 1982-

    2012-12-03

    of convective heat transfer involving suspensions of nanoparticles in coolants (or nanofluids). Flow visualization and quantitative estimation of near-wall temperature profiles were performed using quantum dots and fluorescent dyes. This non-contact measurement...

  14. A Summary of Convective-Core Vertical Velocity Properties Using ARM UHF Wind Profilers in Oklahoma

    E-Print Network [OSTI]

    Ohta, Shigemi

    A Summary of Convective-Core Vertical Velocity Properties Using ARM UHF Wind Profilers in Oklahoma Sciences Division, Argonne National Laboratory, Argonne, Illinois # University of Oklahoma, Norman, Oklahoma @ Bureau of Meteorology, Melbourne, Victoria, Australia & Cooperative Institute for Research

  15. Convective Heat Transfer Enhancement in Nanofluids: Real Anomaly or Analysis Artifact?

    E-Print Network [OSTI]

    Prabhat, Naveen

    The nanofluid literature contains many claims of anomalous convective heat transfer enhancement in both turbulent and laminar flow. To put such claims to the test, we have performed a critical detailed analysis of the ...

  16. Convective cloud and rainfall processes over the Maritime Continent : simulation and analysis of the diurnal cycle

    E-Print Network [OSTI]

    Gianotti, Rebecca L. (Rebecca Louise)

    2013-01-01

    The Maritime Continent experiences strong moist convection, which produces significant rainfall and drives large fluxes of heat and moisture to the upper troposphere. Despite the importance of these processes to global ...

  17. HYDRODYNAMIC SIMULATIONS OF H ENTRAINMENT AT THE TOP OF He-SHELL FLASH CONVECTION

    SciTech Connect (OSTI)

    Woodward, Paul R.; Lin, Pei-Hung; Herwig, Falk E-mail: fherwig@uvic.ca

    2015-01-01

    We present the first three-dimensional, fully compressible gas-dynamics simulations in 4? geometry of He-shell flash convection with proton-rich fuel entrainment at the upper boundary. This work is motivated by the insufficiently understood observed consequences of the H-ingestion flash in post-asymptotic giant branch (post-AGB) stars (Sakurai's object) and metal-poor AGB stars. Our investigation is focused on the entrainment process at the top convection boundary and on the subsequent advection of H-rich material into deeper layers, and we therefore ignore the burning of the proton-rich fuel in this study. We find that for our deep convection zone, coherent convective motions of near global scale appear to dominate the flow. At the top boundary convective shear flows are stable against Kelvin-Helmholtz instabilities. However, such shear instabilities are induced by the boundary-layer separation in large-scale, opposing flows. This links the global nature of thick shell convection with the entrainment process. We establish the quantitative dependence of the entrainment rate on grid resolution. With our numerical technique, simulations with 1024{sup 3} cells or more are required to reach a numerical fidelity appropriate for this problem. However, only the result from the 1536{sup 3} simulation provides a clear indication that we approach convergence with regard to the entrainment rate. Our results demonstrate that our method, which is described in detail, can provide quantitative results related to entrainment and convective boundary mixing in deep stellar interior environments with very stiff convective boundaries. For the representative case we study in detail, we find an entrainment rate of 4.38 ± 1.48 × 10{sup –13} M {sub ?} s{sup –1}.

  18. Numerical simualtion of mixed convection over a three-dimensional horizontal backward-facing step 

    E-Print Network [OSTI]

    Barbosa Saldana, Juan Gabriel

    2005-08-29

    -1 NUMERICAL SIMULATION OF MIXED CONVECTION OVER A THREE-DIMENSIONAL HORIZONTAL BACKWARD-FACING STEP A Dissertation by JUAN GABRIEL BARBOSA SALDANA Submitted to the Office of Graduate Studies of Texas A&M University... ? 2005 JUAN GABRIEL BARBOSA SALDANA ALL RIGHTS RESERVED NUMERICAL SIMULATION OF MIXED CONVECTION OVER A THREE-DIMENSIONAL HORIZONTAL BACKWARD-FACING STEP A Dissertation by JUAN GABRIEL BARBOSA SALDANA Submitted to Texas A...

  19. Nighttime atmospheric stability changes and their effects on the temporal intensity of a mesoscale convective complex 

    E-Print Network [OSTI]

    Hovis, Jeffrey Scott

    1988-01-01

    NIGHTTIME ATMOSPHERIC STABILITY CHANGES AND THEIR EFFECTS ON THE TEMPORAL INTENSITY OF A MESOSCALE CONVECTIVE COMPLEX A Thesis JEFFREY SCOTT HOVIS Submitted to the Graduate College of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE May 1988 Major Subject: Meteorology NIGHTTIME ATMOSPHERIC STABILITY CHANGES AND THEIR EFFECTS ON THE TEMPORAL INTENSITY OF A MESOSCALE CONVECTIVE COMPLEX A Thesis JEFFREY SCOTT HOVIS Approved as to style...

  20. Mesoscale environmental models accompanying convection in the Texas HIPLEX region / by Mark Edward Humbert 

    E-Print Network [OSTI]

    Humbert, Mark Edward

    1980-01-01

    MESOSCALE ENVIRONMENTAL MODELS ACCOMPANYING CONVECTION IN THE TEXAS HIPLEX REGION A Thesis by MARK EDWARD HUMBERT Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE May 1980 Major Subject: Meteorology MESOSCALE ENVIRONMENTAL MODELS ACCOMPANYING CONVECTION IN THE TEXAS HIPLEX REGION A Thesis by MARK EDWARD HUMBERT Approved as to style and content by: (Chairman of Co ttee) (Head of Department) (Member...

  1. Convection during the Late Stages of Simmering in Type Ia Supernovae

    E-Print Network [OSTI]

    Piro, Anthony L

    2008-01-01

    Following unstable ignition of carbon, but prior to explosion, a white dwarf (WD) in a Type Ia supernova (SN Ia) undergoes a simmering phase. During this time, a central convective region grows and encompasses ~1 Msun of the WD over a timescale of ~1000 yrs, which sets the thermal and turbulent profile for the subsequent explosion. We study this time-dependent convection and summarize some of the key features that differ from the traditional, steady-state case. We show that the long conductive timescale above the convective zone and the extraction of energy to heat the WD core leads to a decrease of the convective luminosity and characteristic velocities near the convective zone's top boundary. In addition, differences in the composition between the convective core and the conductive exterior will significantly alter the location of this boundary. In this respect, we find the biggest effect due to complete 22Ne sedimentation prior to carbon ignition. These effects add diversity to the possible WD models, whic...

  2. Convection during the Late Stages of Simmering in Type Ia Supernovae

    E-Print Network [OSTI]

    Anthony L. Piro; Philip Chang

    2008-01-08

    Following unstable ignition of carbon, but prior to explosion, a white dwarf (WD) in a Type Ia supernova (SN Ia) undergoes a simmering phase. During this time, a central convective region grows and encompasses ~1 Msun of the WD over a timescale of ~1000 yrs, which sets the thermal and turbulent profile for the subsequent explosion. We study this time-dependent convection and summarize some of the key features that differ from the traditional, steady-state case. We show that the long conductive timescale above the convective zone and the extraction of energy to heat the WD core leads to a decrease of the convective luminosity and characteristic velocities near the convective zone's top boundary. In addition, differences in the composition between the convective core and the conductive exterior will significantly alter the location of this boundary. In this respect, we find the biggest effect due to complete 22Ne sedimentation prior to carbon ignition. These effects add diversity to the possible WD models, which may alter the properties of the SN Ia explosion.

  3. Film condensation of saturated and superheated vapors along isothermal vertical surfaces in mixed convection

    SciTech Connect (OSTI)

    Winkler, C.M.; Chen, T.S.; Minkowycz, W.J.

    1999-09-01

    An analysis for condensation from an isothermal vertical flat plate in mixed convection is reported. The entire mixed convection regime is divided into two regions. One region covers the forced-convection-dominated regime, and the other covers the free-convection-dominated regime. The governing system of equations is first transformed into a dimensionless form by the nonsimilar transformation, separately for each regime, and then solved using the local nonsimilarity method along with a finite difference scheme. Two nonsimilarity parameters are introduced. The parameter {xi}{sub f} = Gr{sub x}/Re{sub x}{sup 2} characterizes the effect of buoyancy force on forced convection, while the parameter {xi}{sub n} = Re{sub x}/Gr{sub x}{sup 1/2} characterizes the effect of forced flow on free convection. Numerical results for pure steam and refrigerant R-134a are presented for both saturated and superheated cases. It is found that the buoyancy force significantly increases the wall shear stress and condensate mass flux. To a lesser degree, the buoyancy force also increases the wall heat flux. Superheating is found to have an insignificant effect on wall heat flux for a pure vapor.

  4. Fingering convection and cloudless models for cool brown dwarf atmospheres

    E-Print Network [OSTI]

    Tremblin, P; Mourier, P; Baraffe, I; Chabrier, G; Drummond, B; Homeier, D; Venot, O

    2015-01-01

    This work aims to improve the current understanding of the atmospheres of brown dwarfs, especially cold ones with spectral type T and Y, whose modeling is a current challenge. Silicate and iron clouds are believed to disappear at the photosphere at the L/T transition, but cloudless models fail to reproduce correctly the spectra of T dwarfs, advocating for the addition of more physics, e.g. other types of clouds or internal energy transport mechanisms. We use a one-dimensional (1D) radiative/convective equilibrium code ATMO to investigate this issue. This code includes both equilibrium and out-of-equilibrium chemistry and solves consistently the PT structure. Included opacity sources are H2-H2, H2-He, H2O, CO, CO2, CH4, NH3, K, Na, and TiO, VO if they are present in the atmosphere. We show that the spectra of Y dwarfs can be accurately reproduced with a cloudless model if vertical mixing and NH3 quenching are taken into account. T dwarf spectra still have some reddening in e.g. J - H compared to cloudless mode...

  5. Radial convection of finite ion temperature, high amplitude plasma blobs

    SciTech Connect (OSTI)

    Wiesenberger, M. Kendl, A.; Madsen, J.

    2014-09-15

    We present results from simulations of seeded blob convection in the scrape-off-layer of magnetically confined fusion plasmas. We consistently incorporate high fluctuation amplitude levels and finite Larmor radius (FLR) effects using a fully nonlinear global gyrofluid model. This is in line with conditions found in tokamak scrape-off-layers (SOL) regions. Varying the ion temperature, the initial blob width, and the initial amplitude, we found an FLR dominated regime where the blob behavior is significantly different from what is predicted by cold-ion models. The transition to this regime is very well described by the ratio of the ion gyroradius to the characteristic gradient scale length of the blob. We compare the global gyrofluid model with a partly linearized local model. For low ion temperatures, we find that simulations of the global model show more coherent blobs with an increased cross-field transport compared to blobs simulated with the local model. The maximal blob amplitude is significantly higher in the global simulations than in the local ones. When the ion temperature is comparable to the electron temperature, global blob simulations show a reduced blob coherence and a decreased cross-field transport in comparison with local blob simulations.

  6. Optimal Heat Transport in Rayleigh-B\\'enard Convection

    E-Print Network [OSTI]

    Sondak, David; Waleffe, Fabian

    2015-01-01

    Steady flows that optimize heat transport are obtained for two-dimensional Rayleigh-B\\'enard convection with no-slip horizontal walls for a variety of Prandtl numbers $Pr$ and Rayleigh number up to $Ra\\sim 10^9$. Power law scalings of $Nu\\sim Ra^{\\gamma}$ are observed with $\\gamma\\approx 0.31$, where the Nusselt number $Nu$ is a non-dimensional measure of the vertical heat transport. Any dependence of the scaling exponent on $Pr$ is found to be extremely weak. On the other hand, the presence of two local maxima of $Nu$ with different horizontal wavenumbers at the same $Ra$ leads to the emergence of two different flow structures as candidates for optimizing the heat transport. For $Pr \\lesssim 7$, optimal transport is achieved at the smaller maximal wavenumber. In these fluids, the optimal structure is a plume of warm rising fluid which spawns left/right horizontal arms near the top of the channel, leading to downdrafts adjacent to the central updraft. For $Pr > 7$ at high-enough Ra, the optimal structure is a...

  7. Sidewall effects in Rayleigh-B\\'enard convection

    E-Print Network [OSTI]

    Stevens, Richard J A M; Verzicco, Roberto

    2014-01-01

    We investigate the influence of the temperature boundary conditions at the sidewall on the heat transport in Rayleigh-B\\'enard (RB) convection using direct numerical simulations. For relatively low Rayleigh numbers Ra the heat transport is higher when the sidewall is isothermal, kept at a temperature $T_c+\\Delta/2$ (where $\\Delta$ is the temperature difference between the horizontal plates and $T_c$ the temperature of the cold plate), than when the sidewall is adiabatic. The reason is that in the former case part of the heat current avoids the thermal resistance of the fluid layer by escaping through the sidewall that acts as a short-circuit. For higher Ra the bulk becomes more isothermal and this reduces the heat current through the sidewall. Therefore the heat flux in a cell with an isothermal sidewall converges to the value obtained with an adiabatic sidewall for high enough Ra ($\\simeq 10^{10}$). However, when the sidewall temperature deviates from $T_c+\\Delta/2$ the heat transport at the bottom and top p...

  8. The role of convective geothermal systems in the generation, migration, and entrapment of oil

    SciTech Connect (OSTI)

    Hulen, J.B. [Univ. of Utah Research Institute, Salt Lake City, UT (United States)

    1995-06-01

    Modern convective geothermal systems (for example, at Yellowstone National Park) and their fossil equivalents, epithermal mineral deposits (like McLaughlin, California) have traditionally been considered poor petroleum prospects. The concentrated heat which drives these systems is commonly viewed as a negative influence: in other words, any oil initially present in or generated by these systems is quickly degraded to a useless carbonaceous residue. This is true in extreme cases, but numerous examples from the Great Basin, the northern California Coast Ranges, and elsewhere suggest that under certain circumstances, geothermal systems can efficiently generate, transport, and entrap significant quantities of producible petroleum. B.R.T. Simoneit has shown that oil can be hydrothermally generated in an {open_quotes} instant{close_quotes} of geologic time. It follows, then, that away from geothermal systems` high-temperature centers (or in wholly moderate-temperature systems), the encompassing shallow thermal anomalies can distill large volumes of oil from otherwise immature hydrocarbon source rocks. Transport of this newly-generated oil is enhanced by the buoyant upwelling of heated aqueous fluid. Porosity for oil transport and storage is created or increased by hydrothermal dissolution of rock-forming or secondary silicates and carbonates. Finally, geothermal {open_quotes}self-sealing{close_quotes} -- the deposition of secondary minerals (especially silica and clay) at the margins of a system -- can provide a very effective hydrocarbon seal. Lee Allison has noted the coincidence of igneous intrusions and oil reservoirs in Nevada. It is suggested that here and elsewhere, both igneous-related and amagmatic geothermal systems in otherwise favorable settings should be viewed as prime petroleum exploration targets.

  9. Multiscale eddy simulation for moist atmospheric convection: Preliminary investigation

    SciTech Connect (OSTI)

    Stechmann, Samuel N., E-mail: stechmann@wisc.edu [Department of Mathematics, University of Wisconsin-Madison (United States); Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison (United States)

    2014-08-15

    A multiscale computational framework is designed for simulating atmospheric convection and clouds. In this multiscale framework, large eddy simulation (LES) is used to model the coarse scales of 100 m and larger, and a stochastic, one-dimensional turbulence (ODT) model is used to represent the fine scales of 100 m and smaller. Coupled and evolving together, these two components provide a multiscale eddy simulation (MES). Through its fine-scale turbulence and moist thermodynamics, MES allows coarse grid cells to be partially cloudy and to encompass cloudy–clear air mixing on scales down to 1 m; in contrast, in typical LES such fine-scale processes are not represented or are parameterized using bulk deterministic closures. To illustrate MES and investigate its multiscale dynamics, a shallow cumulus cloud field is simulated. The fine-scale variability is seen to take a plausible form, with partially cloudy grid cells prominent near cloud edges and cloud top. From earlier theoretical work, this mixing of cloudy and clear air is believed to have an important impact on buoyancy. However, contrary to expectations based on earlier theoretical studies, the mean statistics of the bulk cloud field are essentially the same in MES and LES; possible reasons for this are discussed, including possible limitations in the present formulation of MES. One difference between LES and MES is seen in the coarse-scale turbulent kinetic energy, which appears to grow slowly in time due to incoherent stochastic fluctuations in the buoyancy. This and other considerations suggest the need for some type of spatial and/or temporal filtering to attenuate undersampling of the stochastic fine-scale processes.

  10. Radar range measurements in the atmosphere.

    SciTech Connect (OSTI)

    Doerry, Armin Walter

    2013-02-01

    The earth's atmosphere affects the velocity of propagation of microwave signals. This imparts a range error to radar range measurements that assume the typical simplistic model for propagation velocity. This range error is a function of atmospheric constituents, such as water vapor, as well as the geometry of the radar data collection, notably altitude and range. Models are presented for calculating atmospheric effects on radar range measurements, and compared against more elaborate atmospheric models.

  11. Lead exposure at uncovered outdoor firing ranges

    SciTech Connect (OSTI)

    Goldberg, R.L.; Hicks, A.M.; O'Leary, L.M.; London, S. (University of Southern California School of Medicine, Los Angeles (USA))

    1991-06-01

    Excessive lead exposure in shooting instructors at indoor firing ranges and covered outdoor firing ranges has been documented. The City of Los Angeles assessed exposure of its full-time shooting instructors at uncovered outdoor ranges via air monitoring and blood lead-level measurements. Results of these tests revealed that significant lead exposure and absorption can occur at outdoor firing ranges. The use of copper-jacketed ammunition may decrease air lead levels and decrease lead absorption by range instructors.

  12. Department Sets Aggressive Schedule for New Appliance Standards...

    Broader source: Energy.gov (indexed) [DOE]

    service lamps; fluorescent lamp ballasts; residential dishwashers; ranges and ovens; microwave ovens; residential clothes dryers; room air conditioners; packaged terminal air...

  13. EA-1662: Final Environmental Assessment

    Broader source: Energy.gov [DOE]

    10 CFR Part 430 Energy Conservation Program: EnergyConservation Standards for Certain Consumer Products (Dishwashers, Dehumidifiers, Microwave Ovens, and Electric and Gas Kitchen Ranges and Ovens)

  14. Late-Time Convection in the Collapse of a 23 Solar Mass Star

    E-Print Network [OSTI]

    C. L. Fryer; P. A. Young

    2006-12-06

    The results of a 3-dimensional SNSPH simulation of the core collapse of a 23 solar mass star are presented. This simulation did not launch an explosion until over 600ms after collapse, allowing an ideal opportunity to study the evolution and structure of the convection below the accretion shock to late times. This late-time convection allows us to study several of the recent claims in the literature about the role of convection: is it dominated by an l=1 mode driven by vortical-acoustic (or other) instability, does it produce strong neutron star kicks, and, finally, is it the key to a new explosion mechanism? The convective region buffets the neutron star, imparting a 150-200 km/s kick. Because the l=1 mode does not dominate the convection, the neutron star does not achieve large (>450 km/s) velocities. Finally, the neutron star in this simulation moves, but does not develop strong oscillations, the energy source for a recently proposed supernova engine. We discuss the implications these results have on supernovae, hypernovae (and gamma-ray bursts), and stellar-massed black holes.

  15. The Midlatitude Continental Convective Clouds Experiment (MC3E) sounding network: operations, processing and analysis

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jensen, M. P.; Toto, T.; Troyan, D.; Ciesielski, P. E.; Holdridge, D.; Kyrouac, J.; Schatz, J.; Zhang, Y.; Xie, S.

    2015-01-27

    The Midlatitude Continental Convective Clouds Experiment (MC3E) took place during the spring of 2011 centered in north-central Oklahoma, USA. The main goal of this field campaign was to capture the dynamical and microphysical characteristics of precipitating convective systems in the US Central Plains. A major component of the campaign was a six-site radiosonde array designed to capture the large-scale variability of the atmospheric state with the intent of deriving model forcing data sets. Over the course of the 46-day MC3E campaign, a total of 1362 radiosondes were launched from the enhanced sonde network. This manuscript provides details on the instrumentationmore »used as part of the sounding array, the data processing activities including quality checks and humidity bias corrections and an analysis of the impacts of bias correction and algorithm assumptions on the determination of convective levels and indices. It is found that corrections for known radiosonde humidity biases and assumptions regarding the characteristics of the surface convective parcel result in significant differences in the derived values of convective levels and indices in many soundings. In addition, the impact of including the humidity corrections and quality controls on the thermodynamic profiles that are used in the derivation of a large-scale model forcing data set are investigated. The results show a significant impact on the derived large-scale vertical velocity field illustrating the importance of addressing these humidity biases.« less

  16. The Midlatitude Continental Convective Clouds Experiment (MC3E) sounding network: operations, processing and analysis

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jensen, M. P.; Toto, T.; Troyan, D.; Ciesielski, P. E.; Holdridge, D.; Kyrouac, J.; Schatz, J.

    2014-09-12

    The Midlatitude Continental Convective Clouds Experiment (MC3E) took place during the spring of 2011 centered in north-central Oklahoma, USA. The main goal of this field campaign was to capture the dynamical and microphysical characteristics of precipitating convective systems in the Central Plains. A major component of the campaign was a 6-site radiosonde array designed to capture the large-scale variability of the atmospheric state with the intent of deriving model forcing datasets. Over the course of the 46 day MC3E campaign, a total of 1362 radiosondes were launched from the enhanced sonde network. This manuscript describes the details of the instrumentationmore »used as part of the sounding array, the data processing activities including quality checks and humidity bias corrections and an analysis of the impacts of bias correction and algorithm assumptions on the determination of convective levels and indices. It is found that corrections for known radiosonde humidity biases and assumptions regarding the characteristics of the surface convective parcel result in significant differences in the derived values of convective levels and indices in many soundings.« less

  17. Oscillatory convective modes in red giants: a possible explanation of the long secondary periods

    E-Print Network [OSTI]

    Saio, Hideyuki; Takayama, Masaki; Ita, Yoshifusa

    2015-01-01

    We discuss properties of oscillatory convective modes in low-mass red giants, and compare them with observed properties of the long secondary periods (LSPs) of semi-regular red giant variables. Oscillatory convective modes are very nonadiabatic g$^{-}$ modes and they are present in luminous stars, such as red giants with $\\log L/{\\rm L}_\\odot \\ga 3$. Finite amplitudes for these modes are confined to the outermost nonadiabatic layers, where the radiative energy flux is more important than the convective energy flux. The periods of oscillatory convection modes increase with luminosity, and the growth times are comparable to the oscillation periods. The LSPs of red giants in the Large Magellanic Cloud (LMC) are observed to lie on a distinct period-luminosity sequence called sequence D. This sequence D period-luminosity relation is roughly consistent with the predictions for dipole oscillatory convective modes in AGB models if we adopt a mixing length of 1.2 pressure scale height ($\\alpha = 1.2$). However, the ef...

  18. Whirling Hexagons and Defect Chaos in Hexagonal Non-Boussinesq Convection

    E-Print Network [OSTI]

    Yuan-Nan Young; Hermann Riecke; Werner Pesch

    2003-07-25

    We study hexagon patterns in non-Boussinesq convection of a thin rotating layer of water. For realistic parameters and boundary conditions we identify various linear instabilities of the pattern. We focus on the dynamics arising from an oscillatory side-band instability that leads to a spatially disordered chaotic state characterized by oscillating (whirling) hexagons. Using triangulation we obtain the distribution functions for the number of pentagonal and heptagonal convection cells. In contrast to the results found for defect chaos in the complex Ginzburg-Landau equation and in inclined-layer convection, the distribution functions can show deviations from a squared Poisson distribution that suggest non-trivial correlations between the defects.

  19. Convective Heat Transfer Augmentation by Flexible fins in Laminar Channel Pulsating flow

    E-Print Network [OSTI]

    Joshi, Rakshitha U; Bhardwaj, Rajneesh

    2015-01-01

    Fluid-structure interaction (FSI) of thin flexible fins coupled with convective heat transfer has applications in energy harvesting and in understanding functioning of several biological systems. We numerically investigate FSI of the thin flexible fins involving large-scale flow-induced deformation as a potential heat transfer enhancement technique. An in-house, strongly-coupled fluid-structure interaction (FSI) solver is employed in which flow and structure solvers are based on sharp-interface immersed boundary and finite element method, respectively. We consider twin flexible fins in a heated channel with laminar pulsating cross flow. The vortex ring past the fin sweep higher sources of vorticity generated on the channel walls out into the downstream - promoting the mixing of the fluid. The moving fin assists in convective mixing, augmenting convection in bulk and at the walls; and thereby reducing thermal boundary layer thickness and improving heat transfer at the channel walls. The thermal augmentation is...

  20. CYCLIC THERMAL SIGNATURE IN A GLOBAL MHD SIMULATION OF SOLAR CONVECTION

    SciTech Connect (OSTI)

    Cossette, Jean-Francois; Charbonneau, Paul; Smolarkiewicz, Piotr K.

    2013-11-10

    Global magnetohydrodynamical simulations of the solar convection zone have recently achieved cyclic large-scale axisymmetric magnetic fields undergoing polarity reversals on a decadal time scale. In this Letter, we show that these simulations also display a thermal convective luminosity that varies in-phase with the magnetic cycle, and trace this modulation to deep-seated magnetically mediated changes in convective flow patterns. Within the context of the ongoing debate on the physical origin of the observed 11 yr variations in total solar irradiance, such a signature supports the thesis according to which all, or part, of the variations on decadal time scales and longer could be attributed to a global modulation of the Sun's internal thermal structure by magnetic activity.

  1. Stability and error analysis of nodal expansion method for convection-diffusion equation

    SciTech Connect (OSTI)

    Deng, Z.; Rizwan-Uddin; Li, F.; Sun, Y.

    2012-07-01

    The development, and stability and error analyses of nodal expansion method (NEM) for one dimensional steady-state convection diffusion equation is presented. Following the traditional procedure to develop NEM, the discrete formulation of the convection-diffusion equation, which is similar to the standard finite difference scheme, is derived. The method of discrete perturbation analysis is applied to this discrete form to study the stability of the NEM. The scheme based on the NEM is found to be stable for local Peclet number less than 4.644. A maximum principle is proved for the NEM scheme, followed by an error analysis carried out by applying the Maximum principle together with a carefully constructed comparison function. The scheme for the convection diffusion equation is of second-order. Numerical experiments are carried and the results agree with the conclusions of the stability and error analyses. (authors)

  2. Stellar models with mixing length and T(tau) relations calibrated on 3D convection simulations

    E-Print Network [OSTI]

    Salaris, Maurizio

    2015-01-01

    (abridged) The calculation of the thermal stratification in the superadiabatic layers of stellar models with convective envelopes is a long standing problem of stellar astrophysics, and has a major impact on predicted observational properties like radius and effective temperature. The Mixing Length Theory, almost universally used to model the superadiabatic convective layers, contains effectively one free parameter to be calibrated --alpha(ml)-- whose value controls the resulting effective temperature. Here we present the first self-consistent stellar evolution models calculated by employing the atmospheric temperature stratification, Rosseland opacities, and calibrated variable alpha(ml) (dependent on effective temperature and surface gravity) from a large suite of three-dimensional radiation hydrodynamics simulations of stellar convective envelopes and atmospheres for solar stellar composition (Trampedach et al. 2013). From our calculations (with the same composition of the radiation hydrodynamics simulatio...

  3. The Mid-latitude Continental Convective Clouds (MC3E) Experiment Final Campaign Report

    SciTech Connect (OSTI)

    Jensen, Michael [Brookhaven National Lab. (BNL), Upton, NY (United States); Kollias, Pavlos [McGill Univ., Montreal, QC (Canada); Giangrande, Scott [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2014-04-01

    The Mid-latitude Continental Convective Clouds Experiment (MC3E) took place from April 22 through June 6, 2011, centered at the ARM Southern Great Plains site (http://www.arm.gov/sites/sgp) in northcentral Oklahoma. MC3E was a collaborative effort between the ARM Climate Research Facility and the National Aeronautics and Space Administration’s (NASA’s) Global Precipitation Measurement (GPM) mission Ground Validation (GV) program. The campaign leveraged the largest ground-based observing infrastructure available in the central United States, including recent upgrades through the American Recovery and Reinvestment Act of 2009, combined with an extensive sounding array, remote sensing and in situ aircraft observations, and additional radar and in situ precipitation instrumentation. The overarching goal of the campaign was to provide a three-dimensional characterization of convective clouds and precipitation for the purpose of improving the representation of convective lifecycle in atmospheric models and the reliability of satellite-based retrievals of precipitation.

  4. Can cellular convection in a rotating spherical shell maintain both global and local magnetic fields?

    E-Print Network [OSTI]

    A. V. Getling; R. D. Simitev; F. H. Busse

    2006-10-25

    A convection-driven MHD dynamo in a rotating spherical shell, with clearly defined structural elements in the flow and magnetic field, is simulated numerically. Such dynamos can be called deterministic, in contrast to those explicitly dependent on the assumed properties of turbulence. The cases most interesting from the standpoint of studying the nature of stellar magnetism demonstrate the following features. On a global scale, the convective flows can maintain a ``general'' magnetic field with a sign-alternating dipolar component. Local (in many cases, bipolar) magnetic structures are associated with convection cells. Disintegrating local structures change into background fields, which drift toward the poles. From time to time, reversals of the magnetic fields in the polar regions occur, as ``new'' background fields expel the ``old'' fields.

  5. Constructing a Merged Cloud-Precipitation Radar Dataset for Tropical Convective Clouds during the DYNAMO/AMIE Experiment at Addu Atoll

    SciTech Connect (OSTI)

    Feng, Zhe; McFarlane, Sally A.; Schumacher, Courtney; Ellis, Scott; Comstock, Jennifer M.; Bharadwaj, Nitin

    2014-05-16

    To improve understanding of the convective processes key to the Madden-Julian-Oscillation (MJO) initiation, the Dynamics of the MJO (DYNAMO) and Atmospheric Radiation Measurement MJO Investigation Experiment (AMIE) collected four months of observations from three radars, the S-band Polarization Radar (S-Pol), the C-band Shared Mobile Atmospheric Research & Teaching Radar (SMART-R), and Ka-band Zenith Radar (KAZR) on Addu Atoll in the tropical Indian Ocean. This study compares the measurements from the S-Pol and SMART-R to those from the more sensitive KAZR in order to characterize the hydrometeor detection capabilities of the two scanning precipitation radars. Frequency comparisons for precipitating convective clouds and non-precipitating high clouds agree much better than non-precipitating low clouds for both scanning radars due to issues in ground clutter. On average, SMART-R underestimates convective and high cloud tops by 0.3 to 1.1 km, while S-Pol underestimates cloud tops by less than 0.4 km for these cloud types. S-Pol shows excellent dynamic range in detecting various types of clouds and therefore its data are well suited for characterizing the evolution of the 3D cloud structures, complementing the profiling KAZR measurements. For detecting non-precipitating low clouds and thin cirrus clouds, KAZR remains the most reliable instrument. However, KAZR is attenuated in heavy precipitation and underestimates cloud top height due to rainfall attenuation 4.3% of the time during DYNAMO/AMIE. An empirical method to correct the KAZR cloud top heights is described, and a merged radar dataset is produced to provide improved cloud boundary estimates, microphysics and radiative heating retrievals.

  6. Meridional flow in the solar convection zone. I. Measurements from gong data

    SciTech Connect (OSTI)

    Kholikov, S. [National Solar Observatories, Tucson, AZ 85719 (United States); Serebryanskiy, A. [Ulugh Beg Astronomical Institute, Uzbek Academy of Science, Tashkent 100052 (Uzbekistan); Jackiewicz, J., E-mail: kholikov@noao.edu [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States)

    2014-04-01

    Large-scale plasma flows in the Sun's convection zone likely play a major role in solar dynamics on decadal timescales. In particular, quantifying meridional motions is a critical ingredient for understanding the solar cycle and the transport of magnetic flux. Because the signal of such features can be quite small in deep solar layers and be buried in systematics or noise, the true meridional velocity profile has remained elusive. We perform time-distance helioseismology measurements on several years worth of Global Oscillation Network Group Doppler data. A spherical harmonic decomposition technique is applied to a subset of acoustic modes to measure travel-time differences to try to obtain signatures of meridional flows throughout the solar convection zone. Center-to-limb systematics are taken into account in an intuitive yet ad hoc manner. Travel-time differences near the surface that are consistent with a poleward flow in each hemisphere and are similar to previous work are measured. Additionally, measurements in deep layers near the base of the convection zone suggest a possible equatorward flow, as well as partial evidence of a sign change in the travel-time differences at mid-convection zone depths. This analysis on an independent data set using different measurement techniques strengthens recent conclusions that the convection zone may have multiple 'cells' of meridional flow. The results may challenge the common understanding of one large conveyor belt operating in the solar convection zone. Further work with helioseismic inversions and a careful study of systematic effects are needed before firm conclusions of these large-scale flow structures can be made.

  7. Convective plasma stability consistent with MHD equilibrium in magnetic confinement systems with a decreasing field

    SciTech Connect (OSTI)

    Tsventoukh, M. M. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2010-10-15

    A study is made of the convective (interchange, or flute) plasma stability consistent with equilibrium in magnetic confinement systems with a magnetic field decreasing outward and large curvature of magnetic field lines. Algorithms are developed which calculate convective plasma stability from the Kruskal-Oberman kinetic criterion and in which the convective stability is iteratively consistent with MHD equilibrium for a given pressure and a given type of anisotropy in actual magnetic geometry. Vacuum and equilibrium convectively stable configurations in systems with a decreasing, highly curved magnetic field are calculated. It is shown that, in convectively stable equilibrium, the possibility of achieving high plasma pressures in the central region is restricted either by the expansion of the separatrix (when there are large regions of a weak magnetic field) or by the filamentation of the gradient plasma current (when there are small regions of a weak magnetic field, in which case the pressure drops mainly near the separatrix). It is found that, from the standpoint of equilibrium and of the onset of nonpotential ballooning modes, a kinetic description of convective stability yields better plasma confinement parameters in systems with a decreasing, highly curved magnetic field than a simpler MHD model and makes it possible to substantially improve the confinement parameters for a given type of anisotropy. For the Magnetor experimental compact device, the maximum central pressure consistent with equilibrium and stability is calculated to be as high as {beta} {approx} 30%. It is shown that, for the anisotropy of the distribution function that is typical of a background ECR plasma, the limiting pressure gradient is about two times steeper than that for an isotropic plasma. From a practical point of view, the possibility is demonstrated of achieving better confinement parameters of a hot collisionless plasma in systems with a decreasing, highly curved magnetic field than those obtained with the simplest MHD description.

  8. Nuclear Physics Long Range Plan | Jefferson Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Nuclear Physics Long Range Plan June 26, 2014 For a couple of years now, we have been waiting to get started on the next nuclear physics long range plan (LRP). What does that mean?...

  9. Viking Range: Order (2014-CE-23014)

    Broader source: Energy.gov [DOE]

    DOE ordered Viking Range, LLC to pay a $8,000 civil penalty after finding Viking Range had failed to certify that certain models of cooking products comply with the applicable energy conservation standards.

  10. American Range: Order (2014-CE-23006)

    Broader source: Energy.gov [DOE]

    DOE ordered American Range Corporation to pay a $8,000 civil penalty after finding American Range had failed to certify that certain models of cooking products comply with the applicable energy conservation standards.

  11. Adapting a Fourier pseudospectral method to Dirichlet boundary conditions for Rayleigh--B\\'enard convection

    E-Print Network [OSTI]

    Ramos, I C

    2015-01-01

    We present the adaptation to non--free boundary conditions of a pseudospectral method based on the (complex) Fourier transform. The method is applied to the numerical integration of the Oberbeck--Boussinesq equations in a Rayleigh--B\\'enard cell with no-slip boundary conditions for velocity and Dirichlet boundary conditions for temperature. We show the first results of a 2D numerical simulation of dry air convection at high Rayleigh number ($R\\sim10^9$). These results are the basis for the later study, by the same method, of wet convection in a solar still.

  12. Effect of wind speed on the growth of the upper convective zone in a solar pond 

    E-Print Network [OSTI]

    McMinn, Steven Lee

    1990-01-01

    EFFECT OF WIND SPEED ON THE GROWTH OF THE UPPER CONVECTIVE ZONE IN A SOLAR POND A Thesis by STEVEN LEE MCMINN Submitted to the Office of Graduate Studies of Texas ASM University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE December 1990 Major Subject: Mechanical Engineering EFFECT OF WIND SPEED ON THE GROWTH OF THE UPPER CONVECTIVE ZONE IN A SOLAR POND A Thesis by STEVEN LEE MCMINN Approved as to style and content by: W. R. Laster (Chair...

  13. A New Model for Mixing By Double-Diffusive Convection (Semi-Convection). III. Thermal and Compositional Transport Through Non-Layered ODDC

    E-Print Network [OSTI]

    Moll, Ryan; Stellmach, Stephan

    2015-01-01

    Oscillatory double-diffusive convection (ODDC) (also known as semi- convection) refers to a type of double diffusive instability that occurs in regions of planetary and stellar interiors which have a destabilizing thermal stratification and a stabilizing mean molecular weight stratification. In this series of papers, we use an extensive suite of three-dimensional (3D) numerical simulations to quantify the transport of heat and chemical species by ODDC. Rosenblum et al. (2011) first showed that ODDC can either spontaneously form layers, which significantly enhance the transport of heat and chemical species compared to mi- croscopic transport, or remain in a state dominated by large scale gravity waves, in which there is a more modest enhancement of the turbulent transport rates. Subsequent studies in this series have focused on identifying under what condi- tions layers form (Mirouh et al. 2012), and quantifying transport through layered systems (Wood et al. 2013). Here we proceed to characterize transport thr...

  14. Range Fuels Commercial-Scale Biorefinery

    Broader source: Energy.gov [DOE]

    The Range Fuels commercial-scale biorefinery will use a variety of feedstocks to create cellulosic ethanol, methanol, and power.

  15. Development of a stochastic convection R. J. Keane, R. S. Plant, N. E. Bowler, W. J. Tennant

    E-Print Network [OSTI]

    Plant, Robert

    ­ p.6/45 #12;Rank Histograms of surface temperature Development of a stochastic convection scheme ­ p of a stochastic convection scheme ­ p.8/45 #12;Climate modelling of heavy pre- cipitation Sun et. al. J. Clim The distribution will be different in reality, but the variability will be similar. Development of a stochastic

  16. Chaotic flow in a 2D natural convection loop with heat flux boundaries William F. Louisos a,b,

    E-Print Network [OSTI]

    Danforth, Chris

    . Examples of natural convection cells occurring in engineering devices include solar water heaters, nu into the system while the upper half is cooled by an equal-but- opposite heat flux out of the system. Water between landmass and an adjacent body of water; mantle convection of the Earth's asthenosphere which

  17. Evolution of the Vertical Thermodynamic Profile during the Transition from Shallow to Deep Convection during CuPIDO 2006*

    E-Print Network [OSTI]

    the action of gravity waves. In the second case, dry air aloft was moistened through the action of the shallow convection thus preventing the erosion of the convective turrets through entrainment of dry air to cumulonimbus as de- scribed by Zehnder et al. (2006). Zehnder et al. attribute the relatively slow development

  18. Urban and land surface effects on the 30 July 2003 mesoscale convective system event observed in the southern Great Plains

    E-Print Network [OSTI]

    Niyogi, Dev

    Urban and land surface effects on the 30 July 2003 mesoscale convective system event observed/Atmosphere Mesoscale Prediction System (COAMPS 1 ) to investigate the impact of urban and land vegetation processes on the prediction of the mesoscale convective system (MCS) observed on 30 July 2003 in the vicinity of Oklahoma City

  19. Modeling of Vertical Ground Loop Heat Exchangers with Variable Convective Resistance and Thermal Mass of the Fluid

    E-Print Network [OSTI]

    Modeling of Vertical Ground Loop Heat Exchangers with Variable Convective Resistance and Thermal-term behavior of ground loop heat exchangers (GLHE) is critical to the design and energy analysis of ground in the tube to guarantee a low convective heat transfer resistance. However, for some antifreeze types

  20. A Fundamental Study of Convective Mixing of CO2 in Heterogeneous Geologic Media using Surrogate Fluids and Numerical Modeling

    E-Print Network [OSTI]

    , H. A., and Huppert H. E., 2010, Convective dissolution of carbon dioxide in saline aquifers, GeophysA Fundamental Study of Convective Mixing of CO2 in Heterogeneous Geologic Media using Surrogate mechanisms contributing to storage of supercritical CO2 (scCO2) in deep saline geologic formations. When

  1. October 1986 R. H. Johnson 721 Lower-Tropospheric Warming and Drying in Tropical Mesoscale Convective Systems

    E-Print Network [OSTI]

    Johnson, Richard H.

    October 1986 R. H. Johnson 721 Lower-Tropospheric Warming and Drying in Tropical Mesoscale components of tropical mesoscale convective systems. It is found that while the apparent heat source Q1 of mesoscale downdrafts within the mesoscale convective systems. The warming and drying at low levels

  2. Arbitrary nonlinearities in convective population dynamics with small diffusion I. D. Peixoto, L. Giuggioli, and V. M. Kenkre

    E-Print Network [OSTI]

    Kenkre, V.M.

    of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico 87131, USA Received 28 April 2005 interaction terms 11,12 , and the addition of convective terms signifying "wind effects" 13­17 . Most is important. There are clear physical situations 13­15 in which wind effects which add the convective term

  3. The relationship between atmospheric convective radiative effect and net1 energy transport in the tropical warm pool2

    E-Print Network [OSTI]

    Hartmann, Dennis

    of the atmospheric cloud radiative effect in determining the magnitude of hor- izontal export of energy, they increase the re- quirement for the atmosphere to export energy from convective regions. Over the warmest that the increased energy export is supplied by the radiative heating from convection. The net cloud radiative effect

  4. Role of convection in redistributing formaldehyde to the upper troposphere over North America and the North Atlantic

    E-Print Network [OSTI]

    Mlllet, Dylan B.

    Role of convection in redistributing formaldehyde to the upper troposphere over North America September 2008. [1] Measurements of formaldehyde (CH2O) from a tunable diode laser absorption spectrometer­model discrepancies in the UT. Citation: Fried, A., et al. (2008), Role of convection in redistributing formaldehyde

  5. A new predictive dynamic model describing the effect of1 the ambient temperature and the convective heat transfer2

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    and the convective heat transfer2 coefficient on bacterial growth3 4 H. Ben Yaghlenea,b* , I. Leguerinela , M. Hamdib Ratkowsky "square root" model and a simplified two-parameter20 heat transfer model regarding an infinite air temperature, the convective heat transfer22 coefficient and the growth parameters of the micro

  6. The Environment of Precipitating Shallow Cumulus Convection LOUISE NUIJENS

    E-Print Network [OSTI]

    Siebesma, Pier

    ), with estimates ranging up to 20%. These estimates are based on subsets of TRMM data for which the majority of Atmospheric and Oceanic Sciences, University of California, Los Angeles, Los Angeles, California BJORN STEVENS Sciences, University of California, Los Angeles, Los Angeles, California A. PIER SIEBESMA Royal Netherlands

  7. Total lightning observations of severe convection over North Texas 

    E-Print Network [OSTI]

    McKinney, Christopher Michael

    2009-05-15

    potential. Total lightning data were obtained from Vaisala Inc.’s Dallas/Fort Worth (D/FW) Lightning Detection and Ranging (LDAR) network. Radar data from two Weather Surveillance Radar – 1988 Doppler (WSR-88D) sites were used for position data...

  8. Generation of mesoscale convective structures in tokamak edge plasma

    SciTech Connect (OSTI)

    Krasheninnikov, S. I.; Smolyakov, A. I. [University of California at San Diego, 9500 Gilman Drive, La Jolla, California 92093 (United States); University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5E2 (Canada)

    2007-10-15

    It is shown that the interplay of the interchange drive and nonlinear effects of Reynolds stress and inverse cascade of drift wave turbulence select a range of plasma parameters (plasma pressure), for which mesoscale perturbations of a certain transverse length scale become unstable. It is suggested that the blob formation is a result of these mesoscale instabilities.

  9. Advection, Moistening, and Shallow-to-deep Convection Transitions During the Initiation and Propagation of Madden-Julian Oscillation

    SciTech Connect (OSTI)

    Hagos, Samson M.; Feng, Zhe; Landu, Kiranmayi; Long, Charles N.

    2014-09-11

    Using observations from the 2011 AMIE/DYNAMO field campaign over the Indian Ocean and a high-resolution regional model simulation, the processes that lead to the rapid shallow-to-deep convection transitions associated with the initiation and eastward propagation of the Madden-Julian Oscillation (MJO) are examined. By tracking the evolution of the depth of several thousand individual model simulated precipitation features, the role of and the processes that control the observed midtropospheric moisture buildup ahead of the detection of deep convection are quantified at large and convection scales. The frequency of shallow-to-deep convection transitions is found to be sensitive to this midlevel moisture and large-scale uplift. This uplift along with the decline of large-scale drying by equator-ward advection causes the moisture buildup leading to the initiation of the MJO. Convection scale moisture variability and uplift, and large-scale zonal advection play secondary roles.

  10. SUMMARY: When temperature differences across the system create a gravitation-ally unstable stratification (top-heavy fluid), convection sets in. Two kinds of con-

    E-Print Network [OSTI]

    Cushman-Roisin, Benoit

    temperatures and pressures are tabulated below. Table 7.1: Values of physical properties of fresh water (at 10- ally unstable stratification (top-heavy fluid), convection sets in. Two kinds of con- vection are distinguished here: top-bottom convection and penetrative convection. The chapter closes with remarks

  11. Tonopah Test Range capabilities: technical manual

    SciTech Connect (OSTI)

    Manhart, R.L.

    1982-11-01

    This manual describes Tonopah Test Range (TTR), defines its testing capabilities, and outlines the steps necessary to schedule tests on the Range. Operated by Sandia National Laboratories, TTR is a major test facility for DOE-funded weapon programs. The Range presents an integrated system for ballistic test vehicle tracking and data acquisition. Multiple radars, optical trackers, telemetry stations, a central computer complex, and combined landline/RF communications systems assure full Range coverage for any type of test. Range operations are conducted by a department within Sandia's Field Engineering Directorate. While the overall Range functions as a complete system, it is operationally divided into the Test Measurements, Instrumentation Development, and Range Operations divisions. The primary function of TTR is to support DOE weapons test activities. Management, however, encourages other Government agencies and their contractors to schedule tests on the Range which can make effective use of its capabilities. Information concerning Range use by organizations outside of DOE is presented. Range instrumentation and support facilities are described in detail. This equipment represents the current state-of-the-art and reflects a continuing commitment by TTR management to field the most effective tracking and data acquisition system available.

  12. 1 Spreading and convective dissolution of carbon dioxide in vertically 2 confined, horizontal aquifers

    E-Print Network [OSTI]

    Neufeld, Jerome A.

    1 Spreading and convective dissolution of carbon dioxide in vertically 2 confined, horizontal] Injection of carbon dioxide (CO2) into saline aquifers is a promising tool for reducing 6 anthropogenic CO2 emissions. At reservoir conditions, the injected CO2 is buoyant relative 7 to the ambient groundwater

  13. Spreading and convective dissolution of carbon dioxide in vertically confined, horizontal aquifers

    E-Print Network [OSTI]

    Huppert, Herbert

    Spreading and convective dissolution of carbon dioxide in vertically confined, horizontal aquifers of carbon dioxide (CO2) into saline aquifers is a promising tool for reducing anthropogenic CO2 emissions. At reservoir conditions, the injected CO2 is buoyant relative to the ambient groundwater. The buoyant plume

  14. Motivation Method Testing Results(1) Instabilities Results(2) Future Viscoelasticity in mantle convection

    E-Print Network [OSTI]

    Cerveny, Vlastislav

    Motivation Method Testing Results(1) Instabilities Results(2) Future Viscoelasticity in mantle@karel.troja.mff.cuni.cz] 14th October 2015 Viscoelasticity in mantle convection Charles University in Prague #12;Motivation Method Testing Results(1) Instabilities Results(2) Future Content Motivation Method Testing: Elastic slab

  15. Contribution of the MODIS instrument to observations of deep convective storms and stratospheric moisture detection

    E-Print Network [OSTI]

    Wang, Pao K.

    . The present work focuses on storm top observations utilizing the MODIS data. The MODIS instrument (availableContribution of the MODIS instrument to observations of deep convective storms and stratospheric/AVHRR and GOES I-M imager instruments have documented the link between certain storm top features referred

  16. AGN-DRIVEN CONVECTION IN GALAXY-CLUSTER PLASMAS Benjamin D. G. Chandran

    E-Print Network [OSTI]

    Chandran, Ben

    heating rate is reduced. This paper focuses on the role of intracluster magnetic fields, which affect plasma heating. It is assumed that plasma heating balances radiative cooling. The plasma heating rate convection by causing heat and cosmic rays to diffuse primarily along magnetic field lines. A new stability

  17. Geophys. J. Int. (0000) 000, 000000 Gross Thermodynamics of 2-component Core Convection

    E-Print Network [OSTI]

    Gubbins, David

    balance and 15% of the heat balance. This means the same magnetic field can be generated with about half the heat throughput needed if the geodynamo were driven by heat alone. Chemical effects are small. Cooling rates below 69 K/Gyr are too low to maintain thermal convection ev- erywhere; when the cooling rate lies

  18. A Method for Diagnosing the Sources of Infrasound in Convective Storm Simulations DAVID A. SCHECTER

    E-Print Network [OSTI]

    Schecter, David

    in a numerical simulation of a convective storm. The method is based on an exact acoustic wave equation-hand side of an inhomogeneous acoustic wave equation (AWE). An exact AWE of the form Lfw(A) 5 åa Sa (1) can addressed. 1. Introduction The term ``infrasound'' refers to acoustic waves with frequencies that are less

  19. Glaciation temperatures of convective clouds ingesting desert dust, air pollution and smoke from forest fires

    E-Print Network [OSTI]

    Daniel, Rosenfeld

    Glaciation temperatures of convective clouds ingesting desert dust, air pollution and smoke from observations show that desert dust and heavy air pollution over East Asia have similar ability to glaciate desert dust, air pollution and smoke from forest fires, Geophys. Res. Lett., 38, L21804, doi:10

  20. Whole-mantle convection and the transition-zone water filter

    E-Print Network [OSTI]

    Whole-mantle convection and the transition-zone water filter David Bercovici & Shun-ichiro Karato-zone water-filter model can explain many geochemical observations while avoiding the major pitfalls an alternative hypothesis that, rather than being divided into isolated reservoirs, the mantle is filtered

  1. SYNOPTIC ENVIRONMENTS AND CONVECTIVE MODES ASSOCIATED WITH SIGNIFICANT TORNADOES IN THE CONTIGUOUS UNITED STATES

    E-Print Network [OSTI]

    1 SYNOPTIC ENVIRONMENTS AND CONVECTIVE MODES ASSOCIATED WITH SIGNIFICANT TORNADOES the formation of the Severe Local Storms (SELS) Center of the United States Weather Bureau in the early 1950s in the early days of SELS was limited largely to pattern recognition, sounding analysis, and subjectively

  2. Unsteady laminar flow and convective heat transfer in a sharp 180 bend

    E-Print Network [OSTI]

    Chung, Yongmann M.

    Unsteady laminar flow and convective heat transfer in a sharp 180° bend Yongmann M. Chung a , Paul Unsteady laminar flow and heat transfer in a sharp 180° bend is studied numerically to investigate to be strong. Ó 2002 Elsevier Science Inc. All rights reserved. Keywords: Laminar; Unsteady; Heat transfer

  3. A scaling analysis of thermoacoustic convection in a zero-gravity environment

    SciTech Connect (OSTI)

    Krane, R.J.; Parang, M.

    1982-01-01

    This paper presents a scaling analysis of a one-dimensional thermoacoustic convection heat transfer process in a zero-gravity environment. The relative importance of the terms in the governing equations is discussed for different time scales without attempting to solve the equations. The scaling analysis suggests certain generalizations that can be made in this class of heat transfer problems.

  4. Fourth Order Compact Difference Scheme for 3D Convection Diffusion Equation with

    E-Print Network [OSTI]

    Zhang, Jun

    Fourth Order Compact Difference Scheme for 3D Convection Diffusion Equation with Boundary Layers University, Washington, DC 20052, USA January 13, 2000 Abstract We present a fourth order compact finite and computational efficiency of the fourth order compact dif­ ference scheme with that of the standard central

  5. Compact fluorescent lamp using horizontal and vertical insulating septums and convective venting geometry

    DOE Patents [OSTI]

    Siminovitch, M.

    1998-02-10

    A novel design is described for a compact fluorescent lamp, including a lamp geometry which will increase light output and efficacy of the lamp in a base down operating position by providing horizontal and vertical insulating septums positioned in the ballast compartment of the lamp to provide a cooler coldspot. Selective convective venting provides additional cooling of the ballast compartment. 9 figs.

  6. PHYSICS OF FLUIDS 25, 024101 (2013) Dissolution-driven convection in a HeleShaw cell

    E-Print Network [OSTI]

    Mahadevan, L.

    2013-01-01

    carbon-dioxide (CO2) storage, we present an experimental study of dissolution-driven convection in a Hele. [http://dx.doi.org/10.1063/1.4790511] I. INTRODUCTION Geological carbon-dioxide storage has emissions into underground storage.1 The proposal is to capture CO2 from point sources (e.g., fossil

  7. Numerical Investigation of Natural Convection Loss in Cavity-Type Solar Receivers

    E-Print Network [OSTI]

    Numerical Investigation of Natural Convection Loss in Cavity-Type Solar Receivers S-mail: Sawat.Paitoonsurikarn@anu.edu.au Abstract In solar thermal systems, especially for high concentration by various previously proposed empirical models. The Clausing model (1981) shows the closest prediction

  8. Measurements of Snow Crystal Growth Dynamics in a Free-fall Convection Chamber

    E-Print Network [OSTI]

    Libbrecht, Kenneth G.

    Measurements of Snow Crystal Growth Dynamics in a Free-fall Convection Chamber Kenneth G. Libbrecht example of this phenomenon is the formation of snow crystals, which are ice crystals that grow from water vapor in an inert background gas. Although this is a relatively simple physical system, snow crystals

  9. Bouyancy-induced convective heat transfer in cylindrical transformers filled with mineral oil with

    E-Print Network [OSTI]

    Walker, D. Greg

    Bouyancy-induced convective heat transfer in cylindrical transformers filled with mineral oil in transformer winding temperature can increase life span by 10% · 3.5 billion gallons of oil used as electrical at 5kVA, 15kVA · tests last for several days at each power level · achieved some "anomalous" readings 7

  10. Convective dissolution of carbon dioxide in saline aquifers Jerome A. Neufeld,1

    E-Print Network [OSTI]

    Huppert, Herbert

    Convective dissolution of carbon dioxide in saline aquifers Jerome A. Neufeld,1 Marc A. Hesse,2 of carbon dioxide in saline aquifers, Geophys. Res. Lett., 37, L22404, doi:10.1029/2010GL044728. [2] The storage of carbon dioxide (CO2) in geological formations has been proposed as a technological means

  11. Passive margins getting squeezed in the mantle convection vice Philippe Yamato,1

    E-Print Network [OSTI]

    Becker, Thorsten W.

    Passive margins getting squeezed in the mantle convection vice Philippe Yamato,1 Laurent Husson,1 2013. [1] Passive margins often exhibit uplift, exhumation, and tectonic inversion. We speculate passive margins. In order to address this issue, we design a 2-D viscous numerical model wherein

  12. Modeling of passive microwave responses in convective situations using output from mesoscale models

    E-Print Network [OSTI]

    Chaboureau, Jean-Pierre

    Modeling of passive microwave responses in convective situations using output from mesoscale models 2003; revised 27 January 2004; accepted 5 February 2004; published 30 March 2004. [1] Passive microwave, which essentially sense cloud tops. Therefore passive microwave observations are a very promising tool

  13. Incorporating self-consistently calculated mineral physics into thermochemical mantle convection simulations

    E-Print Network [OSTI]

    Tackley, Paul J.

    the material properties density, thermal expansivity, specific heat capacity, and seismic velocity is probably due to self-consistent plate tectonics and depth-dependent viscosity. In conclusion, this combined approach of mantle convection and self-consistently calculated mineral physics is a powerful and useful

  14. Elements of comparison between Martian and terrestrial mesoscale meteorological phenomena: Katabatic winds and boundary layer convection

    E-Print Network [OSTI]

    Spiga, Aymeric

    Elements of comparison between Martian and terrestrial mesoscale meteorological phenomena Keywords: Mesoscale meteorology Katabatic winds Boundary layer convection Comparative planetology a b s t r a c t Terrestrial and Martian atmospheres are both characterised by a large variety of mesoscale

  15. Mixing from Fickian Diffusion and Natural Convection in Binary Non-Equilibrium Fluid

    E-Print Network [OSTI]

    Firoozabadi, Abbas

    Mixing from Fickian Diffusion and Natural Convection in Binary Non-Equilibrium Fluid Phases L coefficients Introduction The mixing of two non equilibrium fluid phases is rele- vant to a large number formations is a promising method considered for sequestering CO2 captured from fossil-fuel power plants

  16. The performance of PEM fuel cells fed with oxygen through the free-convection mode

    E-Print Network [OSTI]

    The performance of PEM fuel cells fed with oxygen through the free-convection mode Pei-Wen Li; accepted 27 September 2002 Abstract The feasibility and restrictions of feeding oxygen to a PEM fuel cell at the cathode surface, which can be viewed in terms of the relationship of the fuel cell current density

  17. Urban effects of Chennai on sea breeze induced convection and precipitation

    E-Print Network [OSTI]

    Raman, Sethu

    Urban effects of Chennai on sea breeze induced convection and precipitation Matthew Simpson1 Indian Institute of Technology, New Delhi. e-mail: msimpson@llnl.gov Doppler radar derived wind speed simulations were used to investi- gate the influence of Chennai urban land use on sea breeze initiated

  18. A CALIBRATION OF MIXING LENGTH THEORY BASED ON RHD SIMULATIONS OF SOLARTYPE CONVECTION

    E-Print Network [OSTI]

    ­ formation about the dynamics, thermal structure, and convective efficiency of the superadiabatic region, our models in general do not extend deep enough to include those layers where the mean stratification of the convec­ tion zone becomes adiabatic. While the mean entropy stratification of the hydrodynamical models

  19. IMPACT OF ARM RADIOSONDE HUMIDITY CORRECTION ON CALCULATION OF CONVECTIVE INDICES

    E-Print Network [OSTI]

    IMPACT OF ARM RADIOSONDE HUMIDITY CORRECTION ON CALCULATION OF CONVECTIVE INDICES David Troyan the course of the history of the ARM and ASR Programs, there have been efforts to improve the humidity of humidity calibration in ARM- used Vaisala soundings. Determining additional problems, devising

  20. Natural convection in tunnels at Yucca Mountain and impact on drift seepage

    SciTech Connect (OSTI)

    Halecky, N.; Birkholzer, J.T.; Peterson, P.

    2010-04-15

    The decay heat from radioactive waste that is to be disposed in the once proposed geologic repository at Yucca Mountain (YM) will significantly influence the moisture conditions in the fractured rock near emplacement tunnels (drifts). Additionally, large-scale convective cells will form in the open-air drifts and will serve as an important mechanism for the transport of vaporized pore water from the fractured rock in the drift center to the drift end. Such convective processes would also impact drift seepage, as evaporation could reduce the build up of liquid water at the tunnel wall. Characterizing and understanding these liquid water and vapor transport processes is critical for evaluating the performance of the repository, in terms of water-induced canister corrosion and subsequent radionuclide containment. To study such processes, we previously developed and applied an enhanced version of TOUGH2 that solves for natural convection in the drift. We then used the results from this previous study as a time-dependent boundary condition in a high-resolution seepage model, allowing for a computationally efficient means for simulating these processes. The results from the seepage model show that cases with strong natural convection effects are expected to improve the performance of the repository, since smaller relative humidity values, with reduced local seepage, form a more desirable waste package environment.

  1. Proles of the Bullen parameter from mantle convection Ctirad Matyska aY

    E-Print Network [OSTI]

    Cerveny, Vlastislav

    . Keywords: thermodynamic properties; numerical models; geothermal gradient; mantle; convection 1 of the thermal expansivity and changes of thermal conductivity. We obtained a subadiabatic geotherm above expansivity with depth can result in a subadiabatic geotherm below the upper boundary layer. Thus the profiles

  2. Modulation of radiative heating by the MaddenJulian Oscillation and convectively coupled Kelvin waves

    E-Print Network [OSTI]

    Kuang, Zhiming

    of radiative heating affects the moist static energy budget and potentially the maintenance and propagation are clearly seen in the Outgoing Long- wave Radiation (OLR) data, and its temperature, moisture and wind buoyancy driven convectively coupled waves, processes that alter the column integrated moist static energy

  3. Influence of the Post-Perovskite Transition on Thermal and Thermo-Chemical Mantle Convection

    E-Print Network [OSTI]

    Tackley, Paul J.

    Influence of the Post-Perovskite Transition on Thermal and Thermo-Chemical Mantle Convection Paul J Physique du Globe de Paris, France Several studies have focused on the post-perovskite (PPV) transition, University of British Columbia, Vancouver, Canada. Post-Perovskite: The Last Mantle Phase Transition

  4. Tropical ozone as an indicator of deep convection Ian Folkins and Christopher Braun

    E-Print Network [OSTI]

    Folkins, Ian

    Tropical ozone as an indicator of deep convection Ian Folkins and Christopher Braun Department] The climatological ozone profile in the tropics is shaped like an ``S,'' with a minimum at the surface, a maximum. These features can be reproduced by a very simple model whose only free parameter is the mean ozone mixing ratio

  5. Convergence Proof of Jacobi Iterative Method for A Discretized 2D ConvectionDiffusion Equation \\Lambda

    E-Print Network [OSTI]

    Zhang, Jun

    Convergence Proof of Jacobi Iterative Method for A Discretized 2D Convection­Diffusion Equation \\Lambda Deyu Sang, y Jun Zhang, z and Shiqing Zhang y July 16, 1998 Abstract We prove that the Jacobi been verified numerically but evaded rigorous justification for almost two decades. Key words: Jacobi

  6. Three Dimensional Simulation of Rayleigh-Bénard Convection for Rapid Microscale Polymerase Chain Reaction 

    E-Print Network [OSTI]

    Muddu, Radha Malini Gowri

    2012-02-14

    ................................................................ 5 4 Commercial bench top PCR instrumentation ............................................. 6 5 Prototype of cavity-based convective PCR thermocycling device incorporating a Plexiglas PCR cartridge sandwiched between a top plate... connected to a circulating water bath and a bottom plate incorporating cartridge heaters ......................................................................................... 9 6 Schematic of the process of gel electrophoresis...

  7. FRONT SPEEDS IN THE VANISHING DIFFUSION LIMIT FOR REACTION-DIFFUSION-CONVECTION EQUATIONS

    E-Print Network [OSTI]

    Mascia, Corrado

    velocity. This convergence also yields a reaction- independent sufficient condition for the minimalFRONT SPEEDS IN THE VANISHING DIFFUSION LIMIT FOR REACTION-DIFFUSION-CONVECTION EQUATIONS E.C.M. CROOKS AND C. MASCIA Abstract. Travelling fronts for scalar balance laws with monostable reaction

  8. Reproducibility by Climate Models of Cloud Radiative Forcing Associated with Tropical Convection

    E-Print Network [OSTI]

    Masunaga, Hirohiko

    for monthly mean data from twentieth-century simulations of 18 climate models participating in phase 3 perturbation is thus fundamental for our understanding of climate change, but shows no consistency in eitherReproducibility by Climate Models of Cloud Radiative Forcing Associated with Tropical Convection

  9. Morphology, Intensity, and Rainfall Production of MJO Convection: Observations from DYNAMO Shipborne Radar and TRMM

    E-Print Network [OSTI]

    Collett Jr., Jeffrey L.

    convective populations are essential to MJO initiation. DYNAMO is well suited for testing this hypothesis This study uses Dynamics of the Madden­Julian Oscillation (DYNAMO) shipborne [Research Vessel (R/V) Roger is not well understood and therefore MJO prediction skill is limited, especially con- cerning initiation over

  10. Transpolar voltage and polar cap flux during the substorm cycle and steady convection events

    E-Print Network [OSTI]

    Lockwood, Mike

    of the 10,216 passes is classified by its substorm phase or as a steady convection event (SCE) by inspection of the AE indices. For all phases, we detect a contribution to the transpolar voltage by reconnection is 97% certain during quiet intervals and >99% certain during substorm/SCE growth phases but falls to 75

  11. Heat Transport in Low-Rossby-Number Rayleigh-Benard Convection Keith Julien,1

    E-Print Network [OSTI]

    Knobloch, Edgar

    Heat Transport in Low-Rossby-Number Rayleigh-Be´nard Convection Keith Julien,1 Edgar Knobloch,2, Boulder, Colorado 80309, USA 2 Department of Physics, University of California, Berkeley, California 94720 limits overall heat transport and determines the scaling of the nondimensional Nusselt number Nu

  12. Convective Cell Formation in a Z-Pinch Plasma Science and Fusion Center

    E-Print Network [OSTI]

    Convective Cell Formation in a Z-Pinch J. Kesner Plasma Science and Fusion Center Massachusetts Institute of Technology Cambridge, MA 02139 PSFC Report PSFC/JA-02-27 Abstract Closed field line confinement given by Eq. (1). These equations were then applied to a hard core z pinch which can be considered

  13. Measurement of Convective Entrainment Using Lagrangian Particles KYONGMIN YEO AND DAVID M. ROMPS

    E-Print Network [OSTI]

    Romps, David M.

    Measurement of Convective Entrainment Using Lagrangian Particles KYONGMIN YEO AND DAVID M. ROMPS entrainment rate and of the residence times of entrained parcels within the cloud. The entrainment rate with the Eulerian calculation. The Lagrangian method can also quantify some aspects of entrainment that cannot

  14. Modeling of passive microwave responses in convective situations using output from mesoscale models

    E-Print Network [OSTI]

    Pardo-Carrión, Juan R.

    Modeling of passive microwave responses in convective situations using output from mesoscale models using output from nonhydrostatic mesoscale atmospheric model, Meso-NH, simulations. The radiative for a systematic evaluation of the mesoscale cloud models. An overall good agreement is obtained for both

  15. Power-Aware Deployment and Control of Forced-Convection and Thermoelectric Coolers

    E-Print Network [OSTI]

    Pedram, Massoud

    Power-Aware Deployment and Control of Forced-Convection and Thermoelectric Coolers Mohammad Javad Angeles, CA, USA {dousti, pedram}@usc.edu ABSTRACT Advances in the thermoelectric cooling technology have made it one of the promising solutions for spot cooling in VLSI circuits. Thermoelectric coolers (TECs

  16. Convection Heat Transfer in Three-Dimensional Turbulent Separated/Reattached Flow

    SciTech Connect (OSTI)

    Bassem F. Armaly

    2007-10-31

    The measurements and the simulation of convective heat transfer in separated flow have been a challenge to researchers for many years. Measurements have been limited to two-dimensional flow and simulations failed to predict accurately turbulent heat transfer in the separated and reattached flow region (prediction are higher than measurements by more than 50%). A coordinated experimental and numerical effort has been initiated under this grant for examining the momentum and thermal transport in three-dimensional separated and reattached flow in an effort to provide new measurements that can be used for benchmarking and for improving the simulation capabilities of 3-D convection in separated/reattached flow regime. High-resolution and non-invasive measurements techniques are developed and employed in this study to quantify the magnitude and the behavior of the three velocity components and the resulting convective heat transfer. In addition, simulation capabilities are developed and employed for improving the simulation of 3-D convective separated/reattached flow. Such basic measurements and simulation capabilities are needed for improving the design and performance evaluation of complex (3-D) heat exchanging equipment. Three-dimensional (3-D) convective air flow adjacent to backward-facing step in rectangular channel is selected for the experimental component of this study. This geometry is simple but it exhibits all the complexities that appear in any other separated/reattached flow, thus making the results generated in this study applicable to any other separated and reattached flow. Boundary conditions, inflow, outflow, and wall thermal treatment in this geometry can be well measured and controlled. The geometry can be constructed with optical access for non-intrusive measurements of the flow and thermal fields. A three-component laser Doppler velocimeter (LDV) is employed to measure simultaneously the three-velocity components and their turbulent fluctuations. Infrared thermography is utilized to measure the wall temperature and that information is used to determine the local convective heat transfer coefficient. FLUENT – CFD code is used as the platform in the simulation effort and User Defined Functions are developed for incorporating advanced turbulence models into this simulation code. Predictions of 3-D turbulent convection in separated flow, using the developed simulation capabilities under this grant, compared well with measured results. Results from the above research can be found in the seventeen refereed journal articles, and thirteen refereed publications and presentations in conference proceedings that have been published by the PI during the this grant period. The research effort is still going on and several publications are being prepared for reporting recent results.

  17. Range Design Criteria- June 4, 2012

    Office of Energy Efficiency and Renewable Energy (EERE)

    This document contains the currently-approved firearms "Range Design Criteria" referred to on DOE O 473.3, Protection Program Operations

  18. EM Tackles Cleanup at Tonopah Test Range

    Broader source: Energy.gov [DOE]

    NEVADA – Environmental cleanup experts spent the last weeks of summer on the Tonopah Test Range addressing contaminated equipment and debris at two historical nuclear testing locations.

  19. Supercomputers Take a Cue From Microwave Ovens

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    for one or a few dedicated functions. "Because the ultimate goal of the embedded market is to maximize battery life, these technologies have always been driven by...

  20. Solar Pizza Oven Box k - 6

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX E LIST OF APPLICABLE DIRECTIVES PursuantEnergySolar FlareSolar Phoenix 2Ready to

  1. Formulating and Implementing Profiling over Adaptive Ranges

    E-Print Network [OSTI]

    Sherwood, Tim

    be implemented for range-adaptive profiling. RAP can be used on various profiles, such as PCs, load values may easily be lost in a sea of data. We present range-adaptive profiling (RAP) as a new and general value locality. We propose two methods of implementation of RAP, one in software and the other

  2. Range gated imaging experiments using gated intensifiers

    SciTech Connect (OSTI)

    McDonald, T.E. Jr.; Yates, G.J.; Cverna, F.H.; Gallegos, R.A.; Jaramillo, S.A.; Numkena, D.M.; Payton, J.; Pena-Abeyta, C.R.

    1999-03-01

    A variety of range gated imaging experiments using high-speed gated/shuttered proximity focused microchannel plate image intensifiers (MCPII) are reported. Range gated imaging experiments were conducted in water for detection of submerged mines in controlled turbidity tank test and in sea water for the Naval Coastal Sea Command/US Marine Corps. Field experiments have been conducted consisting of kilometer range imaging of resolution targets and military vehicles in atmosphere at Eglin Air Force Base for the US Air Force, and similar imaging experiments, but in smoke environment, at Redstone Arsenal for the US Army Aviation and Missile Command (AMCOM). Wavelength of the illuminating laser was 532 nm with pulse width ranging from 6 to 12 ns and comparable gate widths. These tests have shown depth resolution in the tens of centimeters range from time phasing reflected LADAR images with MCPII shutter opening.

  3. Effective range from tetramer dissociation data

    E-Print Network [OSTI]

    Hadizadeh, M R; Tomio, Lauro; Delfino, A; Frederico, T

    2012-01-01

    The shifts in the four-body recombination peaks, due to lowest order range corrections in the zero range results close to the unitary limit, are obtained and used to extract the corresponding effective range of a given atomic system. From the experimental values of the tetramer dissociation positions of an ultracold gas of cesium atoms close to broad Feshbach resonances, the effective ranges are extracted, with a weighted average given by 3.9$\\pm 0.8 R_{{vdW}}$, where $R_{{vdW}}$ is the van der Waals length scale. This result is consistent with the van der Waals potential tail for the $Cs_2$ system. The method can be generally applied to other cold atom experimental setups to determine the corresponding effective range.

  4. Neutron scattering and extra short range interactions

    E-Print Network [OSTI]

    V. V. Nesvizhevsky; G. Pignol; K. V. Protasov

    2007-11-14

    The available data on neutron scattering were analyzed to constrain a hypothetical new short-range interaction. We show that these constraints are several orders of magnitude better than those usually cited in the range between 1 pm and 5 nm. This distance range occupies an intermediate space between collider searches for strongly coupled heavy bosons and searches for new weak macroscopic forces. We emphasise the reliability of the neutron constraints in so far as they provide several independent strategies. We have identified the most promising way to improve them.

  5. Techniques for optically compressing light intensity ranges

    SciTech Connect (OSTI)

    Rushford, Michael C.

    1989-01-01

    A pin hole camera assembly for use in viewing an object having a relatively large light intensity range, for example a crucible containing molten uranium in an atomic vapor laser isotope separator (AVLIS) system is disclosed herein. The assembly includes means for optically compressing the light intensity range appearing at its input sufficient to make it receivable and decipherable by a standard video camera. A number of different means for compressing the intensity range are disclosed. These include the use of photogray glass, the use of a pair of interference filters, and the utilization of a new liquid crystal notch filter in combination with an interference filter.

  6. Techniques for optically compressing light intensity ranges

    DOE Patents [OSTI]

    Rushford, M.C.

    1989-03-28

    A pin hole camera assembly for use in viewing an object having a relatively large light intensity range, for example a crucible containing molten uranium in an atomic vapor laser isotope separator (AVLIS) system is disclosed herein. The assembly includes means for optically compressing the light intensity range appearing at its input sufficient to make it receivable and decipherable by a standard video camera. A number of different means for compressing the intensity range are disclosed. These include the use of photogray glass, the use of a pair of interference filters, and the utilization of a new liquid crystal notch filter in combination with an interference filter. 18 figs.

  7. Laser Range Finder Mapping of Floating Vehicle

    E-Print Network [OSTI]

    Hui, Corinna

    2009-01-01

    Using laser range finders as a method of navigation is popular with mobile land robots; however, there has been little research using it with water vehicles. Therefore, this thesis explores the usage and data flow of a ...

  8. Long range transport of acid rain precursors

    E-Print Network [OSTI]

    Fay, James A.

    1983-01-01

    A model of the long range transport of primary and secondary pollutants derived by Fay and Rosenzweig (1) is applied to the problem of the transport of acid rain precursors. The model describes the long term average (annual ...

  9. Tracking Dynamic Boundary Fronts Using Range Sensors

    E-Print Network [OSTI]

    Ramamritham, Krithi

    , tracking forest fires and environmental phenomena. Consider a poisonous gas or plume monitoring ap De- tection and Ranging) are being used for detecting forest fires [6], [7] in the last few years

  10. Systematic ranging and late warning asteroid impacts

    E-Print Network [OSTI]

    Farnocchia, D; Micheli, M

    2015-01-01

    We describe systematic ranging, an orbit determination technique especially suitable to assess the near-term Earth impact hazard posed by newly discovered asteroids. For these late warning cases, the time interval covered by the observations is generally short, perhaps a few hours or even less, which leads to severe degeneracies in the orbit estimation process. The systematic ranging approach gets around these degeneracies by performing a raster scan in the poorly-constrained space of topocentric range and range rate, while the plane of sky position and motion are directly tied to the recorded observations. This scan allows us to identify regions corresponding to collision solutions, as well as potential impact times and locations. From the probability distribution of the observation errors, we obtain a probability distribution in the orbital space and then estimate the probability of an Earth impact. We show how this technique is effective for a number of examples, including 2008 TC3 and 2014 AA, the only tw...

  11. Long range interactions in nanoscale science

    E-Print Network [OSTI]

    Rajter, Richard F.

    Our understanding of the “long range” electrodynamic, electrostatic, and polar interactions that dominate the organization of small objects at separations beyond an interatomic bond length is reviewed. From this basic-forces ...

  12. Underwater vehicle localization using range measurements

    E-Print Network [OSTI]

    Papadopoulos, Ge?rgios

    2010-01-01

    This thesis investigates the problem of cooperative navigation of autonomous marine vehicles using range-only acoustic measurements. We consider the use of a single maneuvering autonomous surface vehicle (ASV) to aid the ...

  13. Active dendrites enhance neuronal dynamic range

    E-Print Network [OSTI]

    Leonardo L. Gollo; Osame Kinouchi; Mauro Copelli

    2009-08-08

    Since the first experimental evidences of active conductances in dendrites, most neurons have been shown to exhibit dendritic excitability through the expression of a variety of voltage-gated ion channels. However, despite experimental and theoretical efforts undertaken in the last decades, the role of this excitability for some kind of dendritic computation has remained elusive. Here we show that, owing to very general properties of excitable media, the average output of a model of active dendritic trees is a highly non-linear function of their afferent rate, attaining extremely large dynamic ranges (above 50 dB). Moreover, the model yields double-sigmoid response functions as experimentally observed in retinal ganglion cells. We claim that enhancement of dynamic range is the primary functional role of active dendritic conductances. We predict that neurons with larger dendritic trees should have larger dynamic range and that blocking of active conductances should lead to a decrease of dynamic range.

  14. Programmable near-infrared ranging system

    DOE Patents [OSTI]

    Everett, Jr., Hobart R. (San Diego, CA)

    1989-01-01

    A high angular resolution ranging system particularly suitable for indoor plications involving mobile robot navigation and collision avoidance uses a programmable array of light emitters that can be sequentially incremented by a microprocessor. A plurality of adjustable level threshold detectors are used in an optical receiver for detecting the threshold level of the light echoes produced when light emitted from one or more of the emitters is reflected by a target or object in the scan path of the ranging system.

  15. Probabilistic Precipitation Forecast Skill as a Function of Ensemble Size and Spatial Scale in a Convection-Allowing Ensemble

    E-Print Network [OSTI]

    Xue, Ming

    Probabilistic Precipitation Forecast Skill as a Function of Ensemble Size and Spatial Scale decreases. These results appear to reflect the broadening of the forecast probability distribution function lead time. They also illustrate that efficient allocation of computing resources for convection

  16. Tropical precipitation variability and convectively coupled equatorial waves1 on submonthly time-scales in reanalyses and TRMM2

    E-Print Network [OSTI]

    Alexander, M. Joan

    convection plays a vital role in global climate by driving large-scale circulation,41 releasing latent heat, modulating radiative forcing, and most importantly redistributing water in42 the earth system. Due to complex

  17. Characterization of thermo-physical properties and forced convective heat transfer of poly-alpha-olefin (PAO) nanofluids. 

    E-Print Network [OSTI]

    Nelson, Ian Carl

    2009-05-15

    of nanoparticles. Hence, nanofluids research has provoked interest in thermal management applications. The convective heat transfer characteristics of nanofluids are reported in this study. Exfoliated graphite nanoparticles were dispersed in poly-alpha-olefin (PAO...

  18. Heat flux scaling in turbulent Rayleigh-Bénard convection with an imposed longitudinal wind

    E-Print Network [OSTI]

    Andrea Scagliarini; Armann Gylfason; Federico Toschi

    2013-11-19

    We present a numerical study of Rayleigh-B\\'enard convection disturbed by a longitudinal wind. Our results show that under the action of the wind, the vertical heat flux through the cell initially decreases, due to the mechanism of plumes-sweeping, and then increases again when turbulent forced convection dominates over the buoyancy. As a result, the Nusselt number is a non-monotonic function of the shear Reynolds number. We provide a simple model that captures with good accuracy all the dynamical regimes observed. We expect that our findings can lead the way to a more fundamental understanding of the of the complex interplay between mean-wind and plumes ejection in the Rayleigh-B\\'enard phenomenology.

  19. The role of convective structures in the poloidal and toroidal rotation in tokamak

    E-Print Network [OSTI]

    Spineanu, Florin

    2013-01-01

    The connection between the poloidal and the toroidal rotation of plasma in tokamak is important for the high confinement regimes, in particular in reactor regime. The sudden onset of closed convection structures in the poloidal section, due to the baroclinic production of vorticity, will sustain a fast increase of the poloidal velocity and a substantial effect on the toroidal rotation. However this is limited to the short time of the onset transition. In real plasma however there is random generation and suppression of convection cells and the sequence of these transient events can prove able to sustain the effect on the toroidal rotation. We formulate a simplified model which consists of a laminar sheared, regular, flow situated at the boundary of a region of drift-wave turbulence. Vortical structures, randomly generated in this turbulent region are spontaneously advected toward the flow and are absorbed there, sustaining with their vortical content, the sheared flow. We examine this dynamics in the wavenumb...

  20. The First Second of a Type-II Supernova: Convection, Accretion, and Shock Propagation

    E-Print Network [OSTI]

    H. -Thomas Janka; Ewald Mueller

    1995-03-03

    One- and two-dimensional hydrodynamical simulations of neutrino-driven supernova explosions are discussed. The simulations cover the phase between the stagnation of the prompt shock and about one second after core bounce. Systematic variation of the neutrino fluxes from the neutrino sphere shows that the explosion energy, explosion time scale, initial mass of the protoneutron star, and explosive nucleosynthesis of iron-group elements depend sensitively on the strength of the neutrino heating during the first few 100 ms after shock formation. Convective overturn in the neutrino-heated region behind the shock is a crucial help for the explosion only in a narrow window of neutrino luminosities. Here powerful explosions can be obtained only in the multi-dimensional case. For higher core-neutrino fluxes also spherically symmetrical models yield energetic explosions, while for lower luminosities even with convection no strong explosions occur.

  1. The Conforming Virtual Element Method for the convection-diffusion-reaction equation with variable coeffcients.

    SciTech Connect (OSTI)

    Manzini, Gianmarco; Cangiani, Andrea; Sutton, Oliver

    2014-10-02

    This document describes the conforming formulations for virtual element approximation of the convection-reaction-diffusion equation with variable coefficients. Emphasis is given to construction of the projection operators onto polynomial spaces of appropriate order. These projections make it possible the virtual formulation to achieve any order of accuracy. We present the construction of the internal and the external formulation. The difference between the two is in the way the projection operators act on the derivatives (laplacian, gradient) of the partial differential equation. For the diffusive regime we prove the well-posedness of the external formulation and we derive an estimate of the approximation error in the H1-norm. For the convection-dominated case, the streamline diffusion stabilization (aka SUPG) is also discussed.

  2. Large scale three-dimensional topology optimisation of heat sinks cooled by natural convection

    E-Print Network [OSTI]

    Alexandersen, Joe; Aage, Niels

    2015-01-01

    This work presents the application of density-based topology optimisation to the design of three-dimensional heat sinks cooled by natural convection. The governing equations are the steady-state incompressible Navier-Stokes equations coupled to the thermal convection-diffusion equation through the Bousinessq approximation. The fully coupled non-linear multiphysics system is solved using stabilised trilinear equal-order finite elements in a parallel framework allowing for the optimisation of large scale problems with order of 40-330 million state degrees of freedom. The flow is assumed to be laminar and several optimised designs are presented for Grashof numbers between $10^3$ and $10^6$. Interestingly, it is observed that the number of branches in the optimised design increases with increasing Grashof numbers, which is opposite to two-dimensional optimised designs.

  3. Noise-Sustained Convective Instability in a Magnetized Taylor-Couette Flow

    SciTech Connect (OSTI)

    W. Liu

    2009-02-20

    The helical magnetorotational instability of the magnetized Taylor-Couette flow is studied numerically in a finite cylinder. A distant upstream insulating boundary is shown to stabilize the convective instability entirely while reducing the growth rate of the absolute instability. The reduction is less severe with larger height. After modeling the boundary conditions properly, the wave patterns observed in the experiment turn out to be a noise-sustained convective instability. After the source of the noise resulted from unstable Ekman and Stewartson layers is switched off, a slowly-decaying inertial oscillation is observed in the simulation. We reach the conclusion that the experiments completed to date have not yet reached the regime of absolute instability.

  4. Noise-sustained convective instability in a magnetized Taylor-Couette flow

    SciTech Connect (OSTI)

    Liu, Wei [Los Alamos National Laboratory

    2008-01-01

    The helical magnetorotational instability of the magnetized Taylor-Couette flow is studied numerically in a finite cylinder. A distant upstream insulating boundary is shown to stabilize the convective instability entirely while reducing the growth rate of the absolute instability. The reduction is less severe with larger height. After modeling the boundary conditions properly, the wave patterns observed in the experiment turn out to be a noise-sustained convective instability. After the source of the noise resulted from unstable Ekman and Stewartson layers is switched off, a slowly-decaying inertial oscillation is observed in the simulation. We reach the conclusion that the experiments completed to date have not yet reached the regime of absolute instability.

  5. Millennial-scale stable oscillations between sea ice and convective deep water formation

    E-Print Network [OSTI]

    Saha, Raj

    2015-01-01

    During the last ice age there were several quasi-periodic abrupt warming events. The climatic effects of the so-called Dansgaard-Oeschger (DO) events were felt globally, although the North Atlantic experienced the largest and most abrupt temperature anomalies. Similar but weaker oscillations also took place during the interglacial period. This paper proposes an auto-oscillatory mechanism between sea ice and convective deep water formation in the north Atlantic as the source of the persistent cycles. A simple dynamical model is constructed by coupling and slightly modifying two existing models of ocean circulation and sea ice. The model exhibits mixed mode oscillations, consisting of decadal scale small amplitude oscillations, and a large amplitude relaxation fluctuation. The decadal oscillations occur due to the insulating effect of sea ice and leads to periodic ventilation of heat from the polar ocean. Gradually an instability builds up in the polar column and results in an abrupt initiation of convection an...

  6. Influence of a coronal envelope as a free boundary to global convective dynamo simulations

    E-Print Network [OSTI]

    Warnecke, Jörn; Käpylä, Maarit J; Brandenburg, Axel

    2015-01-01

    We explore the effects of an outer stably stratified coronal envelope on rotating turbulent convection, differential rotation, and large-scale dynamo action in spherical wedge models of the Sun. We solve the compressible magnetohydrodynamic equations in a two-layer model with unstable stratification below the surface, representing the convection zone, and a stably stratified outer layer, the coronal envelope. The interface emulates essentially a free surface. We compare with models that have no coronal envelope. The presence of a coronal envelope is found to modify the Reynolds stress and the $\\Lambda$-effect resulting in a weaker and non-cylindrical differential rotation. This is related to the reduced latitudinal temperature variations, which are caused by and dependent on the Coriolis force. Some simulations develop a rudimentary near-surface shear layer, which we can relate to a sign change of the meridional Reynolds stress term in the thermal wind balance equation. Furthermore, the presence of a free sur...

  7. Spatial Cross Spectrum: Reducing Incoherent Convective Background of Resolved Heloseismic Instruments

    E-Print Network [OSTI]

    R. A. Garcia; S. Mathur; I. Gonzalez Hernandez; A. Jimenez

    2008-10-09

    Measurements of low-order p modes and gravity modes are perturbed by the solar convective background. Such perturbation increases below 2mHz for intensity measurements and 1mHz for velocity measurements. While the low-degree modes have large spatial scales, the convective motions have much smaller spatial distribution. In this work, we take advantage of these different scale sizes to explore the use of spatial cross spectrum between different regions of the Sun. The aim is to reduce the incoherent background noise and, therefore, increase the signal-to-noise ratio of the signals that are coherent across the full disk. To do so we use the VIRGO/LOI instrument aboard SoHO and the GONG ground-based network to study the intensity and velocity spatial cross spectra.

  8. A multiple-relaxation-time lattice Boltzmann model for convection heat transfer in porous media

    E-Print Network [OSTI]

    Liu, Q; Li, Q

    2013-01-01

    In this paper, a multiple-relaxation-time (MRT) lattice Boltzmann (LB) model is developed for simulating convection heat transfer in porous media at the representative elementary volume scale. In the model, a MRT-LB equation is used to simulate the flow field, while another MRT-LB equation is employed to simulate the temperature field. The effect of the porous media is considered by introducing the porosity into the equilibrium moments, and adding a forcing term to the MRT-LB equation of the flow field in the moment space. The proposed MRT-LB model is validated by numerical simulations of several two-dimensional convection problems in porous media. The numerical results predicted by the present MRT-LB model agree well with those reported in the literature.

  9. Heat transfers in a double-skin roof ventilated by natural convection in summer time

    E-Print Network [OSTI]

    Biwole, Pascal; Pompeo, C

    2013-01-01

    The double-skin roofs investigated in this paper are formed by adding a metallic screen on an existing sheet metal roof. The system enhances passive cooling of dwellings and can help diminishing power costs for air conditioning in summer or in tropical and arid countries. In this work, radiation, convection and conduction heat transfers are investigated. Depending on its surface properties, the screen reflects a large amount of oncoming solar radiation. Natural convection in the channel underneath drives off the residual heat. The bi-dimensional numerical simulation of the heat transfers through the double skin reveals the most important parameters for the system's efficiency. They are, by order of importance, the sheet metal surface emissivity, the screen internal and external surface emissivity, the insulation thickness and the inclination angle for a channel width over 6 cm. The influence of those parameters on Rayleigh and Nusselt numbers is also investigated. Temperature and air velocity profiles on seve...

  10. ARM - Midlatitude Continental Convective Clouds - Single Column Model Forcing (xie-scm_forcing)

    SciTech Connect (OSTI)

    Xie, Shaocheng; McCoy, Renata; Zhang, Yunyan

    2012-10-25

    The constrained variational objective analysis approach described in Zhang and Lin [1997] and Zhang et al. [2001]was used to derive the large-scale single-column/cloud resolving model forcing and evaluation data set from the observational data collected during Midlatitude Continental Convective Clouds Experiment (MC3E), which was conducted during April to June 2011 near the ARM Southern Great Plains (SGP) site. The analysis data cover the period from 00Z 22 April - 21Z 6 June 2011. The forcing data represent an average over the 3 different analysis domains centered at central facility with a diameter of 300 km (standard SGP forcing domain size), 150 km and 75 km, as shown in Figure 1. This is to support modeling studies on various-scale convective systems.

  11. Constraining the difference in convective blueshift between the components of alpha Cen with precise radial velocities

    E-Print Network [OSTI]

    Pourbaix, D; McCarthy, C; Butler, R P; Tinney, C G; Marcy, G W; Jones, H R A; Penny, A J; Carter, B D; Bouchy, F; Pepe, F; Hearnshaw, J B; Skuljan, J; Ramm, D H; Kent, D

    2002-01-01

    New radial velocities of alpha Cen A & B obtained in the framework the Anglo-Australian Planet Search programme as well as in the CORALIE programme are added to those by Endl et al. (2001) to improve the precision of the orbital parameters. The resulting masses are 1.105+/-0.0070 MSun and 0.934+/-0.0061 MSun for A and B respectively. The factors limiting how accurately these masses can be derived from a combined visual-spectroscopic solution are investigated. The total effect of the convective blueshift and the gravitational redshift is also investigated and estimated to differ by 215+/-8 m/s between the components. This suggests that the difference in convective blueshift between the components is much smaller than predicted from current hydrodynamical model atmosphere calculations.

  12. Constraining the difference in convective blueshift between the components of alpha Cen with precise radial velocities

    E-Print Network [OSTI]

    D. Pourbaix; D. Nidever; C. McCarthy; R. P. Butler; C. G. Tinney; G. W. Marcy; H. R. A. Jones; A. J. Penny; B. D. Carter; F. Bouchy; F. Pepe; J. B. Hearnshaw; J. Skuljan; D. Ramm; D. Kent

    2002-02-21

    New radial velocities of alpha Cen A & B obtained in the framework the Anglo-Australian Planet Search programme as well as in the CORALIE programme are added to those by Endl et al. (2001) to improve the precision of the orbital parameters. The resulting masses are 1.105+/-0.0070 MSun and 0.934+/-0.0061 MSun for A and B respectively. The factors limiting how accurately these masses can be derived from a combined visual-spectroscopic solution are investigated. The total effect of the convective blueshift and the gravitational redshift is also investigated and estimated to differ by 215+/-8 m/s between the components. This suggests that the difference in convective blueshift between the components is much smaller than predicted from current hydrodynamical model atmosphere calculations.

  13. ARM - Midlatitude Continental Convective Clouds - Single Column Model Forcing (xie-scm_forcing)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Xie, Shaocheng; McCoy, Renata; Zhang, Yunyan

    The constrained variational objective analysis approach described in Zhang and Lin [1997] and Zhang et al. [2001]was used to derive the large-scale single-column/cloud resolving model forcing and evaluation data set from the observational data collected during Midlatitude Continental Convective Clouds Experiment (MC3E), which was conducted during April to June 2011 near the ARM Southern Great Plains (SGP) site. The analysis data cover the period from 00Z 22 April - 21Z 6 June 2011. The forcing data represent an average over the 3 different analysis domains centered at central facility with a diameter of 300 km (standard SGP forcing domain size), 150 km and 75 km, as shown in Figure 1. This is to support modeling studies on various-scale convective systems.

  14. On the effect of the steady-state approximation in time-space composite studies of mesoscale convective systems 

    E-Print Network [OSTI]

    Mattison, Kevin Morgan

    1992-01-01

    ON THE EFFECT OF THE STRA 'Y-STATE APPROXIMATION IN TIME-SPACE COMPOSITE STUDIES OF MESOSCALE CONVECTIVE SYSTEMS A Thesis KEVIN MORGAN MATTISON Subnitted to the Office of Graduate Studies of Texas A&M University in partial fulfillnent... Studies of Mesoscale Convective Systems. (December 1992) Kevin Morgan Mattison, A. Sc. , Community College of the Air Force; B. S. , Auburn University at Montgomery Chair of Advisory Committee: Dr. Michael I. Biggerstaff This study examined the effects...

  15. Impacts of Microphysical Scheme on Convective and Stratiform Characteristics in Two High Precipitation Squall Line Events

    SciTech Connect (OSTI)

    Wu, Di; Dong, Xiquan; Xi, Baike; Feng, Zhe; Kennedy, Aaron; Mullendore, Gretchen; Gilmore, Matthew; Tao, Wei-Kuo

    2013-10-04

    This study investigates the impact of snow, graupel, and hail processes on the simulated squall lines over the Southern Great Plains in the United States. Weather Research and Forecasting (WRF) model is used to simulate two squall line events in May 2007, and the results are validated against radar and surface observations in Oklahoma. Several microphysics schemes are tested in this study, including WRF 5-Class Microphysics Scheme (WSM5), WRF 6-Class Microphysics Scheme (WSM6), Goddard Three Ice scheme (Goddard 3-ice) with graupel, Goddard Two Ice scheme (Goddard 2-ice), and Goddard 3-ice hail scheme. The simulated surface precipitation is sensitive to the microphysics scheme, and especially to whether graupel or hail category is included. All of the three ice (3-ice) schemes overestimated the total precipitation, within which WSM6 has the highest overestimation. Two ice (2-ice) schemes, missing a graupel/hail category, produced less total precipitation than 3-ice schemes. By applying a radar-based convective/stratiform partitioning algorithm, we find that by including the graupel/hail processes, there is an increase in areal coverage, precipitation intensity, updraft and downdraft intensity in convective region and a reduction of areal coverage and its precipitation intensity in stratiform region. For vertical structures, all the bulk schemes, especially 2-ice schemes, have the highest reflectivity located at upper levels (~8 km), which is unrealistic compared to observations. In addition, this study shows the radar-based convective/stratiform partitioning algorithm can reasonably identify WRF simulated precipitation, wind and microphysics fields in both convective and stratiform regions.

  16. Chaotic mean wind in turbulent thermal convection and long-term correlations in solar activity

    E-Print Network [OSTI]

    A. Bershadskii

    2009-12-25

    It is shown that correlation function of the mean wind velocity in a turbulent thermal convection (Rayleigh number $Ra \\sim 10^{11}$) exhibits exponential decay with a very long correlation time, while corresponding largest Lyapunov exponent is certainly positive. These results together with the reconstructed phase portrait indicate presence of a chaotic component in the examined mean wind. Telegraph approximation is also used to study relative contribution of the chaotic and stochastic components to the mean wind fluctuations and an equilibrium between these components has been studied. Since solar activity is based on the thermal convection processes, it is reasoned that the observed solar activity long-term correlations can be an imprint of the mean wind chaotic properties. In particular, correlation function of the daily sunspots number exhibits exponential decay with a very long correlation time and corresponding largest Lyapunov exponent is certainly positive, also relative contribution of the chaotic and stochastic components follows the same pattern as for the convection mean wind.

  17. Microwave heating device for internal heating convection experiments, applied to Earth's mantle dynamics

    SciTech Connect (OSTI)

    Surducan, E.; Surducan, V.; Neamtu, C.; Limare, A.; Di Giuseppe, E.

    2014-12-15

    We report the design, construction, and performances of a microwave (MW) heating device for laboratory experiments with non-contact, homogeneous internal heating. The device generates MW radiation at 2.47 GHz from a commercial magnetron supplied by a pulsed current inverter using proprietary, feedback based command and control hardware and software. Specially designed MW launchers direct the MW radiation into the sample through a MW homogenizer, devised to even the MW power distribution into the sample's volume. An adjustable MW circuit adapts the MW generator to the load (i.e., the sample) placed in the experiment chamber. Dedicated heatsinks maintain the MW circuits at constant temperature throughout the experiment. Openings for laser scanning for image acquisition with a CCD camera and for the cooling circuits are protected by special MW filters. The performances of the device are analyzed in terms of heating uniformity, long term output power stability, and load matching. The device is used for small scale experiments simulating Earth's mantle convection. The 30 × 30 × 5 cm{sup 3} convection tank is filled with a water?based viscous fluid. A uniform and constant temperature is maintained at the upper boundary by an aluminum heat exchanger and adiabatic conditions apply at the tank base. We characterize the geometry of the convective regime as well as its bulk thermal evolution by measuring the velocity field by Particle Image Velocimetry and the temperature field by using Thermochromic Liquid Crystals.

  18. Convectively stable pressure profile in magnetic confinement systems with internal rings

    SciTech Connect (OSTI)

    Tsventoukh, M. M. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2010-06-15

    A convectively stable pressure profile in a long multiple-mirror (corrugated) magnetic confinement system with internal current-carrying rings is calculated. The plasma energy content in the axial region can be increased by using an internal ring that reverses the on-axis magnetic field direction and gives rise to an average magnetic well near the axis. The pressure profile in the outer region-outside the magnetic well-is considered in detail. It is shown that, in the radial pressure profile, a pedestal can be formed that leads to a higher pressure drop between the center and the plasma edge. The pressure profile is calculated from the Kruskal-Oberman criterion-a necessary and sufficient condition for the convective stability of a collisionless plasma. The revealed pedestal arises near the boundary of the average magnetic well in the region of the smallest but alternating-sign curvature of the magnetic field lines due to a break in the convectively stable pressure profile. Such a shape of the stable pressure profile can be attributed to the stabilizing effect of the alternating-sign curvature of the field lines in the multiple-mirror magnetic confinement systems under consideration.

  19. A review on regional convection-permitting climate modeling: Demonstrations, prospects, and challenges

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Prein, Andreas; Langhans, Wolfgang; Fosser, Giorgia; Ferrone, Andrew; Ban, Nikolina; Goergen, Klaus; Keller, Michael; Tolle, Merja; Gutjahr, Oliver; Feser, Frauke; et al

    2015-05-27

    Regional climate modeling using convection permitting models (CPMs) emerges as a promising framework to provide more reliable climate information on regional to local scales compared to traditionally used large-scale models (LSMs). CPMs do not use convection parameterization schemes, known as a major source of errors and uncertainties, and have more accurate surface and orography elds. The drawback of CPMs is their high demand on computational resources. For this reason, the CPM climate simulations only appeared a decade ago. In this study we aim to provide a common basis for CPM climate simulations by giving a holistic review of the topic.more »The most important components in CPM, such as physical parameterizations and dynamical formulations are discussed, and an outlook on required future developments and computer architectures that would support the application of CPMs is given. Most importantly, this review presents the consolidated outcome of studies that addressed the added value of CPM climate simulations compared to LSMs. Most improvements are found for processes related to deep convection (e.g., precipitation during summer), for mountainous regions, and for the soil-vegetation-atmosphere interactions. The climate change signals of CPM simulations reveal increases in short and extreme rainfall events and an increased ratio of liquid precipitation at the surface (a decrease of hail) potentially leading to more frequent ash oods. Concluding, CPMs are a very promising tool for future climate research. However, coordinated modeling programs are crucially needed to assess their full potential and support their development.« less

  20. Large-scale Environmental Variables and Transition to Deep Convection in Cloud Resolving Model Simulations: A Vector Representation

    SciTech Connect (OSTI)

    Hagos, Samson M.; Leung, Lai-Yung R.

    2012-11-01

    Cloud resolving model simulations and vector analysis are used to develop a quantitative method of assessing regional variations in the relationships between various large-scale environmental variables and the transition to deep convection. Results of the CRM simulations from three tropical regions are used to cluster environmental conditions under which transition to deep convection does and does not take place. Projections of the large-scale environmental variables on the difference between these two clusters are used to quantify the roles of these variables in the transition to deep convection. While the transition to deep convection is most sensitive to moisture and vertical velocity perturbations, the details of the profiles of the anomalies vary from region to region. In comparison, the transition to deep convection is found to be much less sensitive to temperature anomalies over all three regions. The vector formulation presented in this study represents a simple general framework for quantifying various aspects of how the transition to deep convection is sensitive to environmental conditions.

  1. Nuclear burning and mixing in the first stars: entrainment at a convective boundary using the PPB advection scheme

    E-Print Network [OSTI]

    Paul Woodward; Falk Herwig; David Porter; Tyler Fuchs; Anthony Nowatzki; Marco Pignatari

    2007-11-13

    The evolution of the first generations of stars at zero or extremly low metallicity, and especially some crucial properties like the primary N14 production, is charactarized by convective-reactive mixing events that are mostly absent from similar evolution phases at solar-like metallicity. These episodes occur when unprocessed H-rich material is mixed accross a convective boundary into C12 rich He-burning material, as for example in He-shell flashes of extremely-low metallicity AGB stars. In this paper we describe the astrophysical context of such convective-reactive events, including the difficulty of current one-dimensional stellar evolution models to correctly simulate these evolutionary phases. We then describe the requirements and current state of modeling convective-reactive processes in the first stars environment. We demonstrate some of the new concepts that we are applying to this problem, i.e. the highly accurate PPB advection scheme in the framework of PPM hydrodynamic simulations of mixing accross a very stiff convective boundary. We show initial results of such simulations that address the first non-reactive step of this problem, which is the entrainment of H at the top boundary of the He-shell flash convection zone.

  2. Supersymmetric inversion of effective-range expansions

    E-Print Network [OSTI]

    Bikashkali Midya; Jérémie Evrard; Sylvain Abramowicz; O. L. Ramírez Suárez; Jean-Marc Sparenberg

    2015-05-26

    A complete and consistent inversion technique is proposed to derive an accurate interaction potential from an effective-range function for a given partial wave in the neutral case. First, the effective-range function is Taylor or Pad\\'e expanded, which allows high precision fitting of the experimental scattering phase shifts with a minimal number of parameters on a large energy range. Second, the corresponding poles of the scattering matrix are extracted in the complex wave-number plane. Third, the interaction potential is constructed with supersymmetric transformations of the radial Schr\\"odinger equation. As an illustration, the method is applied to the experimental phase shifts of the neutron-proton elastic scattering in the $^1S_0$ and $^1D_2$ channels on the $[0-350]$ MeV laboratory energy interval.

  3. Topological phases with long-range interactions

    E-Print Network [OSTI]

    Gong, Zhe-Xuan; Hu, Anzi; Wall, Michael L; Foss-Feig, Michael; Gorshkov, Alexey V

    2015-01-01

    Topological phases of matter are primarily studied in quantum many-body systems with short-range interactions. Whether various topological phases can survive in the presence of long-range interactions, however, is largely unknown. Here we show that a paradigmatic example of a symmetry-protected topological phase, the Haldane phase of an antiferromagnetic spin-1 chain, surprisingly remains intact in the presence of arbitrarily slowly decaying power-law interactions. The influence of long-range interactions on the topological order is largely quantitative, and we expect similar results for more general systems. Our conclusions are based on large-scale matrix-product-state simulations and two complementary effective-field-theory calculations. The striking agreement between the numerical and analytical results rules out finite-size effects. The topological phase considered here should be experimentally observable in a recently developed trapped-ion quantum simulator.

  4. Topological phases with long-range interactions

    E-Print Network [OSTI]

    Zhe-Xuan Gong; Mohammad F. Maghrebi; Anzi Hu; Michael L. Wall; Michael Foss-Feig; Alexey V. Gorshkov

    2015-05-12

    Topological phases of matter are primarily studied in quantum many-body systems with short-range interactions. Whether various topological phases can survive in the presence of long-range interactions, however, is largely unknown. Here we show that a paradigmatic example of a symmetry-protected topological phase, the Haldane phase of an antiferromagnetic spin-1 chain, surprisingly remains intact in the presence of arbitrarily slowly decaying power-law interactions. The influence of long-range interactions on the topological order is largely quantitative, and we expect similar results for more general systems. Our conclusions are based on large-scale matrix-product-state simulations and two complementary effective-field-theory calculations. The striking agreement between the numerical and analytical results rules out finite-size effects. The topological phase considered here should be experimentally observable in a recently developed trapped-ion quantum simulator.

  5. Extended range radiation dose-rate monitor

    DOE Patents [OSTI]

    Valentine, Kenneth H. (Knoxville, TN)

    1988-01-01

    An extended range dose-rate monitor is provided which utilizes the pulse pileup phenomenon that occurs in conventional counting systems to alter the dynamic response of the system to extend the dose-rate counting range. The current pulses from a solid-state detector generated by radiation events are amplified and shaped prior to applying the pulses to the input of a comparator. The comparator generates one logic pulse for each input pulse which exceeds the comparator reference threshold. These pulses are integrated and applied to a meter calibrated to indicate the measured dose-rate in response to the integrator output. A portion of the output signal from the integrator is fed back to vary the comparator reference threshold in proportion to the output count rate to extend the sensitive dynamic detection range by delaying the asymptotic approach of the integrator output toward full scale as measured by the meter.

  6. Safety assessment of outdoor live fire range

    SciTech Connect (OSTI)

    1989-05-01

    The following Safety Assessment (SA) pertains to the outdoor live fire range facility (LFR). The purpose of this facility is to supplement the indoor LFR. In particular it provides capacity for exercises that would be inappropriate on the indoor range. This SA examines the risks that are attendant to the training on the outdoor LFR. The outdoor LFR used by EG&G Mound is privately owned. It is identified as the Miami Valley Shooting Grounds. Mondays are leased for the exclusive use of EG&G Mound.

  7. Range gating experiments through a scattering media

    SciTech Connect (OSTI)

    Payton, J.; Cverna, F.; Gallegos, R.; McDonald, T.; Numkena, D.; Obst, A.; Pena-Abeyta, C.; Yates, G.

    1998-12-31

    This paper discusses range-gated imaging experiments performed recently at Redstone Arsenal in Huntsville, Alabama. Range gating is an imaging technique that uses a pulsed laser and gated camera to image objects at specific ranges. The technique can be used for imaging through scattering media such as dense smoke or fog. Range gating uses the fact that light travels at 3 x 10{sup 8} m/s. Knowing the speed of light the authors can calculate the time it will take the laser light to travel a known distance, then gate open a Micro Channel Plate Image Intensifier (MCPII) at the time the reflected light returns from the target. In the Redstone experiment the gate width on the MCPII was set to equal the laser pulse width ({approximately} 8 ns) for the highest signal to noise ratio. The gate allows the light reflected form the target and a small portion of the light reflected from the smoke in the vicinity of the target to be imaged. They obtained good results in light and medium smoke but the laser they were used did not have sufficient intensity to penetrate the thickest smoke. They did not diverge the laser beam to cover the entire target in order to maintain a high flux that would achieve better penetration through the smoke. They were able to image an Armored Personnel Carrier (APC) through light and medium smoke but they were not able to image the APC through heavy smoke. The experiment and results are presented.

  8. Impulse radar with swept range gate

    DOE Patents [OSTI]

    McEwan, T.E.

    1998-09-08

    A radar range finder and hidden object locator is based on ultra-wide band radar with a high resolution swept range gate. The device generates an equivalent time amplitude scan with a typical range of 4 inches to 20 feet, and an analog range resolution as limited by a jitter of on the order of 0.01 inches. A differential sampling receiver is employed to effectively eliminate ringing and other aberrations induced in the receiver by the near proximity of the transmit antenna, so a background subtraction is not needed, simplifying the circuitry while improving performance. Techniques are used to reduce clutter in the receive signal, such as decoupling the receive and transmit cavities by placing a space between them, using conductive or radiative damping elements on the cavities, and using terminating plates on the sides of the openings. The antennas can be arranged in a side-by-side parallel spaced apart configuration or in a coplanar opposed configuration which significantly reduces main bang coupling. 25 figs.

  9. 6, 1018310216, 2006 Long-range transport

    E-Print Network [OSTI]

    Boyer, Edmond

    ACPD 6, 10183­10216, 2006 Long-range transport of Asian dust and air pollutants to Taiwan C.-Y. Lin and air pollutants to Taiwan: observed evidence and model simulation C.-Y. Lin 1 , Z. Wang 2 , W.-N. Chen and air pollutants to Taiwan C.-Y. Lin et al. Title Page Abstract Introduction Conclusions References

  10. Compact range for variable-zone measurements

    DOE Patents [OSTI]

    Burnside, Walter D. (Columbus, OH); Rudduck, Roger C. (Columbus, OH); Yu, Jiunn S. (Albuquerque, NM)

    1988-01-01

    A compact range for testing antennas or radar targets includes a source for directing energy along a feedline toward a parabolic reflector. The reflected wave is a spherical wave with a radius dependent on the distance of the source from the focal point of the reflector.

  11. Discussion of long-range weather prediction

    SciTech Connect (OSTI)

    Canavan, G.H.

    1998-09-10

    A group of scientists at Los Alamos have held a series of discussions of the issues in and prospects for improvements in Long-range Weather Predictions Enabled by Proving of the Atmosphere at High Space-Time Resolution. The group contained the requisite skills for a full evaluation, although this report presents only an informal discussion of the main technical issues. The group discussed all aspects of the proposal, which are grouped below into the headings: (1) predictability; (2) sensors and satellites, (3) DIAL and atmospheric sensing; (4) localized transponders; and (5) summary and integration. Briefly, the group agreed that the relative paucity of observations of the state of the atmosphere severely inhibits the accuracy of weather forecasts, and any program that leads to a more dense and uniform observational network is welcome. As shown in Long-range Weather more dense and uniform observational network is welcome. As shown in Long-range Weather Predictions, the pay-back of accurate long-range forecasts should more than justify the expenditure associated with improved observations and forecast models required. The essential step is to show that the needed technologies are available for field test and space qualification.

  12. Method and apparatus for coherent burst ranging

    DOE Patents [OSTI]

    Wachter, E.A.; Fisher, W.G.

    1998-04-28

    A high resolution ranging method is described utilizing a novel modulated waveform, hereafter referred to as coherent burst modulation. In the coherent burst method, high frequency modulation of an acoustic or electromagnetic transmitter, such as a laser, is performed at a modulation frequency. This modulation frequency is transmitted quasi-continuously in the form of interrupted bursts of radiation. Energy from the transmitter is directed onto a target, interacts with the target, and the returning energy is collected. The encoded burst pattern contained in the collected return signal is detected coherently by a receiver that is tuned so as to be principally sensitive to the modulation frequency. The receiver signal is processed to determine target range using both time-of-flight of the burst envelope and phase shift of the high frequency modulation. This approach effectively decouples the maximum unambiguous range and range resolution relationship of earlier methods, thereby allowing high precision ranging to be conducted at arbitrarily long distances using at least one burst of encoded energy. The use of a receiver tuned to the high frequency modulation contained within the coherent burst vastly improves both sensitivity in the detection of the target return signal and rejection of background interferences, such as ambient acoustic or electromagnetic noise. Simultaneous transmission at several energies (or wavelengths) is possible by encoding each energy with a separate modulation frequency or pattern; electronic demodulation at the receiver allows the return pattern for each energy to be monitored independently. Radial velocity of a target can also be determined by monitoring change in phase shift of the return signal as a function of time. 12 figs.

  13. Method and apparatus for coherent burst ranging

    DOE Patents [OSTI]

    Wachter, Eric A. (138 Bay Path Dr., Oak Ridge, TN 37830); Fisher, Walter G. (8514 Carl Valentine, Knoxville, TN 37931)

    1998-01-01

    A high resolution ranging method is described utilizing a novel modulated waveform, hereafter referred to as coherent burst modulation. In the coherent burst method, high frequency modulation of an acoustic or electromagnetic transmitter, such as a laser, is performed at a modulation frequency. This modulation frequency is transmitted quasi-continuously in the form of interrupted bursts of radiation. Energy from the transmitter is directed onto a target, interacts with the target, and the returning energy is collected. The encoded burst pattern contained in the collected return signal is detected coherently by a receiver that is tuned so as to be principally sensitive to the modulation frequency. The receiver signal is processed to determine target range using both time-of-flight of the burst envelope and phase shift of the high frequency modulation. This approach effectively decouples the maximum unambiguous range and range resolution relationship of earlier methods, thereby allowing high precision ranging to be conducted at arbitrarily long distances using at least one burst of encoded energy. The use of a receiver tuned to the high frequency modulation contained within the coherent burst vastly improves both sensitivity in the detection of the target return signal and rejection of background interferences, such as ambient acoustic or electromagnetic noise. Simultaneous transmission at several energies (or wavelengths) is possible by encoding each energy with a separate modulation frequency or pattern; electronic demodulation at the receiver allows the return pattern for each energy to be monitored independently. Radial velocity of a target can also be determined by monitoring change in phase shift of the return signal as a function of time.

  14. Technical support document: Energy efficiency standards for consumer products: Room air conditioners, water heaters, direct heating equipment, mobile home furnaces, kitchen ranges and ovens, pool heaters, fluorescent lamp ballasts and television sets. Volume 3, Water heaters, pool heaters, direct heating equipment, and mobile home furnaces

    SciTech Connect (OSTI)

    Not Available

    1993-11-01

    This is Volume 3 in a series of documents on energy efficiency of consumer products. This volume discusses energy efficiency of water heaters. Water heaters are defined by NAECA as products that utilize oil, gas, or electricity to heat potable water for use outside the heater upon demand. These are major appliances, which use a large portion (18% on average) of total energy consumed per household (1). They differ from most other appliances in that they are usually installed in obscure locations as part of the plumbing and are ignored until they fail. Residential water heaters are capable of heating water up to 180{degrees}F, although the setpoints are usually set lower.

  15. Wide range radioactive gas concentration detector

    DOE Patents [OSTI]

    Anderson, David F. (Los Alamos, NM)

    1984-01-01

    A wide range radioactive gas concentration detector and monitor which is capable of measuring radioactive gas concentrations over a range of eight orders of magnitude. The device of the present invention is designed to have an ionization chamber which is sufficiently small to give a fast response time for measuring radioactive gases but sufficiently large to provide accurate readings at low concentration levels. Closely spaced parallel plate grids provide a uniform electric field in the active region to improve the accuracy of measurements and reduce ion migration time so as to virtually eliminate errors due to ion recombination. The parallel plate grids are fabricated with a minimal surface area to reduce the effects of contamination resulting from absorption of contaminating materials on the surface of the grids. Additionally, the ionization chamber wall is spaced a sufficient distance from the active region of the ionization chamber to minimize contamination effects.

  16. Rangely, Colorado: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onRAPID/Geothermal/Exploration/Colorado <RAPID/Geothermal/WaterEnergy Marketing CorpMember Corp JumpRangely, Colorado:

  17. Inertial range turbulence in kinetic plasmas

    E-Print Network [OSTI]

    Howes, G G

    2007-01-01

    The transfer of turbulent energy through an inertial range from the driving scale to dissipative scales in a kinetic plasma followed by the conversion of this energy into heat is a fundamental plasma physics process. A theoretical foundation for the study of this process is constructed, but the details of the kinetic cascade are not well understood. Several important properties are identified: (a) the conservation of a generalized energy by the cascade; (b) the need for collisions to increase entropy and realize irreversible plasma heating; and (c) the key role played by the entropy cascade--a dual cascade of energy to small scales in both physical and velocity space--to convert ultimately the turbulent energy into heat. A strategy for nonlinear numerical simulations of kinetic turbulence is outlined. Initial numerical results are consistent with the operation of the entropy cascade. Inertial range turbulence arises in a broad range of space and astrophysical plasmas and may play an important role in the ther...

  18. Inertial range turbulence in kinetic plasmas

    E-Print Network [OSTI]

    G. G. Howes

    2007-11-27

    The transfer of turbulent energy through an inertial range from the driving scale to dissipative scales in a kinetic plasma followed by the conversion of this energy into heat is a fundamental plasma physics process. A theoretical foundation for the study of this process is constructed, but the details of the kinetic cascade are not well understood. Several important properties are identified: (a) the conservation of a generalized energy by the cascade; (b) the need for collisions to increase entropy and realize irreversible plasma heating; and (c) the key role played by the entropy cascade--a dual cascade of energy to small scales in both physical and velocity space--to convert ultimately the turbulent energy into heat. A strategy for nonlinear numerical simulations of kinetic turbulence is outlined. Initial numerical results are consistent with the operation of the entropy cascade. Inertial range turbulence arises in a broad range of space and astrophysical plasmas and may play an important role in the thermalization of fusion energy in burning plasmas.

  19. Stratiform and Convective Precipitation Observed by Multiple Radars during the DYNAMO/AMIE Experiment

    SciTech Connect (OSTI)

    Deng, Min; Kollias, Pavlos; Feng, Zhe; Zhang, Chidong; Long, Charles N.; Kalesse, Heike; Chandra, Arunchandra; Kumar, Vickal; Protat, Alain

    2014-11-01

    The motivation for this research is to develop a precipitation classification and rain rate estimation method using cloud radar-only measurements for Atmospheric Radiation Measurement (ARM) long-term cloud observation analysis, which are crucial and unique for studying cloud lifecycle and precipitation features under different weather and climate regimes. Based on simultaneous and collocated observations of the Ka-band ARM zenith radar (KAZR), two precipitation radars (NCAR S-PolKa and Texas A&M University SMART-R), and surface precipitation during the DYNAMO/AMIE field campaign, a new cloud radar-only based precipitation classification and rain rate estimation method has been developed and evaluated. The resulting precipitation classification is equivalent to those collocated SMART-R and S-PolKa observations. Both cloud and precipitation radars detected about 5% precipitation occurrence during this period. The convective (stratiform) precipitation fraction is about 18% (82%). The 2-day collocated disdrometer observations show an increased number concentration of large raindrops in convective rain compared to dominant concentration of small raindrops in stratiform rain. The composite distributions of KAZR reflectivity and Doppler velocity also show two distinct structures for convective and stratiform rain. These indicate that the method produces physically consistent results for two types of rain. The cloud radar-only rainfall estimation is developed based on the gradient of accumulative radar reflectivity below 1 km, near-surface Ze, and collocated surface rainfall (R) measurement. The parameterization is compared with the Z-R exponential relation. The relative difference between estimated and surface measured rainfall rate shows that the two-parameter relation can improve rainfall estimation.

  20. Temperature, humidity and air flow in the emplacement drifts using convection and dispersion transport models

    SciTech Connect (OSTI)

    Danko, G.; Birkholzer, J.T.; Bahrami, D.; Halecky, N.

    2009-10-01

    A coupled thermal-hydrologic-airflow model is developed, solving for the transport processes within a waste emplacement drift and the surrounding rockmass together at the proposed nuclear waste repository at Yucca Mountain. Natural, convective air flow as well as heat and mass transport in a representative emplacement drift during post-closure are explicitly simulated, using the MULTIFLUX model. The conjugate, thermal-hydrologic transport processes in the rockmass are solved with the TOUGH2 porous-media simulator in a coupled way to the in-drift processes. The new simulation results show that large-eddy turbulent flow, as opposed to small-eddy flow, dominate the drift air space for at least 5000 years following waste emplacement. The size of the largest, longitudinal eddy is equal to half of the drift length, providing a strong axial heat and moisture transport mechanism from the hot to the cold drift sections. The in-drift results are compared to those from simplified models using a surrogate, dispersive model with an equivalent dispersion coefficient for heat and moisture transport. Results from the explicit, convective velocity simulation model provide higher axial heat and moisture fluxes than those estimated from the previously published, simpler, equivalent-dispersion models, in addition to showing differences in temperature, humidity and condensation rate distributions along the drift length. A new dispersive model is also formulated, giving a time- and location-variable function that runs generally about ten times higher in value than the highest dispersion coefficient currently used in the Yucca Mountain Project as an estimate for the equivalent dispersion coefficient in the emplacement drift. The new dispersion coefficient variation, back-calculated from the convective model, can adequately describe the heat and mass transport processes in the emplacement drift example.

  1. Utilizing CLASIC observations and multiscale models to study the impact of improved Land surface representation on modeling cloud- convection

    SciTech Connect (OSTI)

    Niyogi, Devdutta S.

    2013-06-07

    The CLASIC experiment was conducted over the US southern great plains (SGP) in June 2007 with an objective to lead an enhanced understanding of the cumulus convection particularly as it relates to land surface conditions. This project was design to help assist with understanding the overall improvement of land atmosphere convection initiation representation of which is important for global and regional models. The study helped address one of the critical documented deficiency in the models central to the ARM objectives for cumulus convection initiation and particularly under summer time conditions. This project was guided by the scientific question building on the CLASIC theme questions: What is the effect of improved land surface representation on the ability of coupled models to simulate cumulus and convection initiation? The focus was on the US Southern Great Plains region. Since the CLASIC period was anomalously wet the strategy has been to use other periods and domains to develop the comparative assessment for the CLASIC data period, and to understand the mechanisms of the anomalous wet conditions on the tropical systems and convection over land. The data periods include the IHOP 2002 field experiment that was over roughly same domain as the CLASIC in the SGP, and some of the DOE funded Ameriflux datasets.

  2. Population genetic analysis of a recent range expansion: mechanisms regulating the poleward range limit

    E-Print Network [OSTI]

    Grosberg, Rick

    with the range limit. We infer that the primary cause of the northern range boundary in T. rubescens is migration mechanisms--genetic impoverishment, migration load, or a physical barrier to dis- persal--are well described similarly affect all taxa in a region whose distributional limits are established by migration load

  3. Penta-hepta defect chaos in a model for rotating hexagonal convection

    E-Print Network [OSTI]

    Yuan-Nan Young; Hermann Riecke

    2002-09-19

    In a model for rotating non-Boussinesq convection with mean flow we identify a regime of spatio-temporal chaos that is based on a hexagonal planform and is sustained by the {\\it induced nucleation} of dislocations by penta-hepta defects. The probability distribution function for the number of defects deviates substantially from the usually observed Poisson-type distribution. It implies strong correlations between the defects inthe form of density-dependent creation and annihilation rates of defects. We extract these rates from the distribution function and also directly from the defect dynamics.

  4. Liquid oil painting: Free and forced convection in an enclosure with mechanical and thermal forcing

    E-Print Network [OSTI]

    Sheard, Gregory J; King, Martin P

    2012-01-01

    A fluid dynamics video is linked to this article, which have been submitted to the Gallery of Fluid Motion as part of the 65th American Physical Society meeting of the Division of Fluid Dynamics, held in San Diego, California, USA, over 17-20 November 2012. The video serves to visualize flows generated in a rectangular enclosure that are subjected to both mechanical and thermal forcing through a common horizontal boundary. This system exhibits features consistent with either horizontal convection or lid-driven cavity flows depending on the ratio between thermal and mechanical stirring, and three different cases are visualized in the linked videos.

  5. Experimental and numerical study of laminar forced convection heat transfer for a dimpled heat sink 

    E-Print Network [OSTI]

    Park, Do Seo

    2009-05-15

    of the copper plate. The outer surface of the test section consisted of fiberglass to reduce heat loss to the outside surroundings. The blower was turned on and air was forced through the test setup. The flow rate through the test section was controlled... STUDY OF LAMINAR FORCED CONVECTION HEAT TRANSFER FOR A DIMPLED HEAT SINK A Thesis by DO SEO PARK Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER...

  6. Convection in X-ray Bursts Michael Zingale Stony Brook University

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit the followingConcentratingPortal ControllingConvection feedbacks in a

  7. Multichannel long-range Rydberg molecules

    E-Print Network [OSTI]

    Eiles, Matthew T

    2015-01-01

    A generalized class of ultra-long-range Rydberg molecules is proposed which consist of a multichannel Rydberg atom whose outermost electron creates a chemical bond with a distant ground state atom. Such multichannel Rydberg molecules exhibit favorable properties for laser excitation, because states exist where the quantum defect varies strongly with the principal quantum number. The resulting occurrence of near degeneracies with states of high orbital angular momentum promotes the admixture of low $l$ into the high $l$ deeply bound `trilobite' molecule states, thereby circumventing the usual difficulty posed by electric dipole selection rules. Such states also can exhibit multi-scale binding possibilities that could present novel options for quantum manipulation.

  8. Tonopah Test Range 2030 Meeting Summary Report

    SciTech Connect (OSTI)

    NSTec Environmental Restoration

    2009-04-01

    Corrective Action Sites (CASs) and Corrective Action Units (CAUs) at the Tonopah Test Range (TTR) may be placed into three categories: Closed, Closed in Place, or Closure in Progress. CASs and CAUs where contaminants were either not detected or were cleaned up to within regulatory action levels are summarized. CASs and CAUs where contaminants and/or waste have been closed in place are summarized. There is also a table that summarizes the contaminant that has been closed at each site, if land-use restrictions are present, and if post-closure inspections are required.

  9. Fan-less long range alpha detector

    DOE Patents [OSTI]

    MacArthur, D.W.; Bounds, J.A.

    1994-05-10

    A fan-less long range alpha detector is disclosed which operates by using an electrical field between a signal plane and the surface or substance to be monitored for air ions created by collisions with alpha radiation. Without a fan, the detector can operate without the possibility of spreading dust and potential contamination into the atmosphere. A guard plane between the signal plane and the electrically conductive enclosure and maintained at the same voltage as the signal plane, reduces leakage currents. The detector can easily monitor soil, or other solid or liquid surfaces. 2 figures.

  10. Rangely Oilfield Geothermal Area | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoop Inc Jump to:Newberg,Energy LLCALLETEREFU Elektronik GmbHRahusRamkyRange Fuels

  11. Help:Range blocks | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX E LISTStar2-0057-EA JumpDuimen River PowerHeckert BXT SolarHelioNova S LLinkedRange

  12. Range Fuels Biorefinery Groundbreaking | Department of Energy

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousMathematicsEnergyInterested PartiesBuildingBudget ||Department ofRequest7of 9 RadiologicalRainRancherRange

  13. Convective heat transfer in the laminar-turbulent transition region with molten salt in a circular tube

    SciTech Connect (OSTI)

    Yu-ting, Wu; Bin, Liu; Chong-fang, Ma; Hang, Guo [Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education and Key Laboratory of Heat Transfer and Energy Conversion, Beijing municipality, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100022 (China)

    2009-10-15

    In order to understand the heat transfer characteristics of molten salt and testify the validity of the well-known empirical convective heat transfer correlations, experimental study on transition convective heat transfer with molten salt in a circular tube was conducted. Molten salt circulations were realized and operated in a specially designed system over 1000 h. The average forced convective heat transfer coefficients of molten salt were determined by least-squares method based on the measured data of flow rates and temperatures. Finally, a heat transfer correlation of transition flow with molten salt in a circular tube was obtained and good agreement was observed between the experimental data of molten salt and the well-known correlations presented by Hausen and Gnielinski, respectively. (author)

  14. Convection Triggering

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit the followingConcentratingPortal Controlling

  15. The role of subsurface flows in solar surface convection: modeling the spectrum of supergranular and larger scale flows

    SciTech Connect (OSTI)

    Lord, J. W.; Rast, M. P.; Cameron, R. H.; Rempel, M.; Roudier, T.

    2014-09-20

    We model the solar horizontal velocity power spectrum at scales larger than granulation using a two-component approximation to the mass continuity equation. The model takes four times the density scale height as the integral (driving) scale of the vertical motions at each depth. Scales larger than this decay with height from the deeper layers. Those smaller are assumed to follow a Kolmogorov turbulent cascade, with the total power in the vertical convective motions matching that required to transport the solar luminosity in a mixing length formulation. These model components are validated using large-scale radiative hydrodynamic simulations. We reach two primary conclusions. (1) The model predicts significantly more power at low wavenumbers than is observed in the solar photospheric horizontal velocity spectrum. (2) Ionization plays a minor role in shaping the observed solar velocity spectrum by reducing convective amplitudes in the regions of partial helium ionization. The excess low wavenumber power is also seen in the fully nonlinear three-dimensional radiative hydrodynamic simulations employing a realistic equation of state. This adds to other recent evidence suggesting that the amplitudes of large-scale convective motions in the Sun are significantly lower than expected. Employing the same feature tracking algorithm used with observational data on the simulation output, we show that the observed low wavenumber power can be reproduced in hydrodynamic models if the amplitudes of large-scale modes in the deep layers are artificially reduced. Since the large-scale modes have reduced amplitudes, modes on the scale of supergranulation and smaller remain important to convective heat flux even in the deep layers, suggesting that small-scale convective correlations are maintained through the bulk of the solar convection zone.

  16. Oscillatory instability and routes to chaos in Rayleigh-Bénard convection: effect of external magnetic field

    E-Print Network [OSTI]

    Yada Nandukumar; Pinaki Pal

    2015-10-19

    We investigate oscillatory instability and routes to chaos in Rayleigh-B\\'enard convection of electrically conducting fluids in presence of external horizontal magnetic field. Three dimensional direct numerical simulations (DNS) of the governing equations are performed for the investigation. DNS shows that oscillatory instability is inhibited by the magnetic field. The supercritical Rayleigh number for the onset of oscillation is found to scale with the Chandrasekhar number $\\mathrm{Q}$ as $\\mathrm{Q}^{\\alpha}$ in DNS with $\\alpha = 1.8$ for low Prandtl numbers ($\\mathrm{Pr}$). Most interestingly, DNS shows $\\mathrm{Q}$ dependent routes to chaos for low Prandtl number fluids like mercury ($\\mathrm{Pr} = 0.025$). For low $\\mathrm{Q}$, period doubling routes are observed, while, quasiperiodic routes are observed for high $\\mathrm{Q}$. The bifurcation structure associated with $\\mathrm{Q}$ dependent routes to chaos is then understood by constructing a low dimensional model from the DNS data. The model also shows similar scaling laws as DNS. Bifurcation analysis of the low dimensional model shows that origin of different routes are associated with the bifurcation structure near the primary instability. These observations show similarity with the previous results of convection experiments performed with mercury.

  17. Thermal convection with large viscosity variation in an enclosure with localized heating

    SciTech Connect (OSTI)

    Chu, T.Y.; Hickox, C.E.

    1988-01-01

    The present study is undertaken in order to gain an understanding of convective transport in a magma chamber. We have chosen to represent the chamber by an enclosure with localized heating from below. Results of both laboratory experiments and computer modeling are reported. The experimental apparatus consists of a transparent enclosure with a square planform. An electrically heated strip, with a width equal to one-fourth of the length of a side of the enclosure, is centered on the lower inside surface of the enclosure. For the experiments reported here, the top of the fluid layer is maintained at a constant temperature and the depth of the layer is equal to the width of the heated strip. The large viscosity variation characteristic of magma convection is simulated by using corn syrup as the working fluid. Measured velocity and temperature distribution as well as overall heat transfer rates are presented. The experiment is numerically simulated through use of a finite element computer program. Numerically predicted streamlines, isotherms, and velocity distributions are presented for the transverse vertical midplane of the enclosure. Good agreement is demonstrated between predictions and measurements. 23 refs., 8 figs., 2 tabs.

  18. Calculation of natural convection test at Phenix using the NETFLOW++ code

    SciTech Connect (OSTI)

    Mochizuki, H.; Kikuchi, N.; Li, S.

    2012-07-01

    The present paper describes modeling and analyses of a natural convection of the pool-type fast breeder reactor Phenix. The natural convection test was carried out as one of the End of Life Tests of the Phenix. Objective of the present study is to assess the applicability of the NETFLOW++ code which has been verified thus far using various water facilities and validated using the plant data of the loop-type FBR 'Monju' and the loop-type experimental fast reactor 'Joyo'. The Phenix primary heat transport system is modeled based on the benchmark documents available from IAEA. The calculational model consists of only the primary heat transport system with boundary conditions on the secondary-side of IHX. The coolant temperature at the primary pump inlet, the primary coolant temperature at the IHX inlet and outlet, the secondary coolant temperatures and other parameters are calculated by the code where the heat transfer between the hot and cold pools is explicitly taken into account. A model including the secondary and tertiary systems was prepared, and the calculated results also agree well with the measured data in general. (authors)

  19. Enhanced tracer transport by the spiral defect chaos state of a convecting fluid

    E-Print Network [OSTI]

    K. -H. Chiam; M. C. Cross; H. S. Greenside; P. F. Fischer

    2004-09-23

    To understand how spatiotemporal chaos may modify material transport, we use direct numerical simulations of the three-dimensional Boussinesq equations and of an advection-diffusion equation to study the transport of a passive tracer by the spiral defect chaos state of a convecting fluid. The simulations show that the transport is diffusive and is enhanced by the spatiotemporal chaos. The enhancement in tracer diffusivity follows two regimes. For large Peclet numbers (that is, small molecular diffusivities of the tracer), we find that the enhancement is proportional to the Peclet number. For small Peclet numbers, the enhancement is proportional to the square root of the Peclet number. We explain the presence of these two regimes in terms of how the local transport depends on the local wave numbers of the convection rolls. For large Peclet numbers, we further find that defects cause the tracer diffusivity to be enhanced locally in the direction orthogonal to the local wave vector but suppressed in the direction of the local wave vector.

  20. Three-Dimensional Simulations of SASI- and Convection-Dominated Core-Collapse Supernovae

    E-Print Network [OSTI]

    Rodrigo Fernández

    2015-07-01

    We investigate the effect of dimensionality on the transition to explosion in neutrino-driven core-collapse supernovae. Using parameterized hydrodynamic simulations of the stalled supernova shock in one-, two- (2D), and three spatial dimensions (3D), we systematically probe the extent to which hydrodynamic instabilities alone can tip the balance in favor of explosion. In particular, we focus on systems that are well into the regimes where the Standing Accretion Shock Instability (SASI) or neutrino-driven convection dominate the dynamics, and characterize the difference between them. We find that SASI-dominated models can explode with up to ~20% lower neutrino luminosity in 3D than in 2D, with the magnitude of this difference decreasing with increasing resolution. This improvement in explosion conditions is related to the ability of spiral modes to generate more non-radial kinetic energy than a single sloshing mode, increasing the size of the average shock radius, and hence generating better conditions for the formation of large-scale, high-entropy bubbles. In contrast, convection-dominated explosions show a smaller difference in their critical heating rate between 2D and 3D (<8%), in agreement with previous studies. The ability of our numerical implementation to maintain arbitrary symmetries is quantified with a set of SASI-based tests. We discuss implications for the diversity of explosion paths in a realistic supernova environment.