Powered by Deep Web Technologies
Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Modeling-Computer Simulations (Lewicki & Oldenburg, 2004) | Open Energy  

Open Energy Info (EERE)

Modeling-Computer Simulations (Lewicki & Oldenburg, Modeling-Computer Simulations (Lewicki & Oldenburg, 2004) Exploration Activity Details Location Unspecified Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not indicated DOE-funding Unknown Notes In this section we present numerical simulations of CO2 migration, seepage, and atmospheric dispersion. The purpose of these simulations is to evaluate the magnitudes and form of anomalous CO2 concentrations and fluxes that might be expected to emanate from a given model hidden geothermal system. From this information, we can design and evaluate potential monitoring and detection methods. References Jennifer L. Lewicki, Curtis M. Oldenburg (2004) Strategies For Detecting Hidden Geothermal Systems By Near-Surface Gas Monitoring Retrieved from

2

Modeling-Computer Simulations | Open Energy Information  

Open Energy Info (EERE)

Modeling-Computer Simulations Modeling-Computer Simulations Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Modeling-Computer Simulations Details Activities (78) Areas (31) Regions (5) NEPA(0) Exploration Technique Information Exploration Group: Data and Modeling Techniques Exploration Sub Group: Modeling Techniques Parent Exploration Technique: Modeling Techniques Information Provided by Technique Lithology: Stratigraphic/Structural: Stress fields and magnitudes Hydrological: Visualization and prediction of the flow patterns and characteristics of geothermal fluids Thermal: Thermal conduction and convection patterns in the subsurface Cost Information Low-End Estimate (USD): 85.008,500 centUSD 0.085 kUSD 8.5e-5 MUSD 8.5e-8 TUSD / hour Median Estimate (USD): 195.0019,500 centUSD

3

Modeling-Computer Simulations At Fish Lake Valley Area (Deymonaz...  

Open Energy Info (EERE)

Additional References Retrieved from "http:en.openei.orgwindex.php?titleModeling-ComputerSimulationsAtFishLakeValleyArea(Deymonaz,EtAl.,2008)&oldid387627...

4

Modeling-Computer Simulations At Long Valley Caldera Geothermal...  

Open Energy Info (EERE)

Tempel, Et Al., 2011) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Long Valley Caldera Geothermal Area...

5

Modeling-Computer Simulations At Chocolate Mountains Area (Alm...  

Open Energy Info (EERE)

Area (Alm, Et Al., 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Chocolate Mountains Area (Alm, Et Al.,...

6

Modeling-Computer Simulations At White Mountains Area (Goff ...  

Open Energy Info (EERE)

GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At White Mountains Area (Goff & Decker, 1983) Exploration Activity Details Location White...

7

Modeling-Computer Simulations At Stillwater Area (Wisian & Blackwell, 2004)  

Open Energy Info (EERE)

Stillwater Area (Wisian & Blackwell, 2004) Stillwater Area (Wisian & Blackwell, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Stillwater Area (Wisian & Blackwell, 2004) Exploration Activity Details Location Stillwater Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not indicated DOE-funding Unknown References Kenneth W. Wisian, David D. Blackwell (2004) Numerical Modeling Of Basin And Range Geothermal Systems Retrieved from "http://en.openei.org/w/index.php?title=Modeling-Computer_Simulations_At_Stillwater_Area_(Wisian_%26_Blackwell,_2004)&oldid=387304" Categories: Exploration Activities DOE Funded Activities What links here Related changes Special pages Printable version

8

Modeling-Computer Simulations (Combs, Et Al., 1999) | Open Energy  

Open Energy Info (EERE)

Modeling-Computer Simulations (Combs, Et Al., 1999) Modeling-Computer Simulations (Combs, Et Al., 1999) Exploration Activity Details Location Unspecified Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful DOE-funding Unknown Notes Various models/simulations used to analyze data obtained from slimhole drilling. References Jim Combs, John T. Finger, Colin Goranson, Charles E. Hockox Jr., Ronald D. Jacobsen, Gene Polik (1999) Slimhole Handbook- Procedures And Recommendations For Slimhole Drilling And Testing In Geothermal Exploration Retrieved from "http://en.openei.org/w/index.php?title=Modeling-Computer_Simulations_(Combs,_Et_Al.,_1999)&oldid=387232" Category: Exploration Activities What links here Related changes Special pages Printable version Permanent link Browse properties

9

Modeling-Computer Simulations At Raft River Geothermal Area (1983) | Open  

Open Energy Info (EERE)

Modeling-Computer Simulations At Raft River Geothermal Area (1983) Modeling-Computer Simulations At Raft River Geothermal Area (1983) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Raft River Geothermal Area (1983) Exploration Activity Details Location Raft River Geothermal Area Exploration Technique Modeling-Computer Simulations Activity Date 1983 Usefulness useful DOE-funding Unknown Exploration Basis Predict flow rate and porosity Notes The objectives of the physical modeling effort are to: (1) evaluate injection-backflow testing for fractured reservoirs under conditions of known reservoir parameters (porosity, fracture width, etc.); (2) study the mechanisms controlling solute transport in fracture systems; and (3) provide data for validation of numerical models that explicitly simulate

10

Modeling-Computer Simulations (Laney, 2005) | Open Energy Information  

Open Energy Info (EERE)

Modeling-Computer Simulations (Laney, 2005) Modeling-Computer Simulations (Laney, 2005) Exploration Activity Details Location Unspecified Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not indicated DOE-funding Unknown Notes Design of Sampling Strategies to Detect CO2 Emissions From Hidden Geothermal Systems, Lewicki, Oldenburg and Kennedy. The objective of this project is to investigate geothermal CO2 monitoring in the near surface as a tool to discover hidden geothermal reservoirs. A primary goal of this project is to develop an approach that places emphasis on cost and time-efficient near-surface exploration methods and yields results to guide and focus more cost-intensive geophysical measurements, installation of deep wells, and geochemical analyses of deep fluids. To this end, we

11

Modeling-Computer Simulations (Ozkocak, 1985) | Open Energy Information  

Open Energy Info (EERE)

Ozkocak, 1985) Ozkocak, 1985) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations (Ozkocak, 1985) Exploration Activity Details Location Unspecified Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not indicated DOE-funding Unknown Notes CONTRIBUTION OF THE LATEST ADVANCES IN GEOLOGY, GEOCHEMISTRY AND GEOPHYSICS TO GEOTHERMAL PROSPECTING. Twenty-five papers were received on this topic, 14 of them concerning geology, four geochemistry and seven geophysics. The papers dealing with geology describe attempts to build models of underground geothermal activity and study the factors that control the formation of reservoir and cap rocks (regional plate tectonics, local tectonics, stratigraphy, geochemistry and volcanism) and the relations

12

Modeling-Computer Simulations At U.S. West Region (Laney, 2005) | Open  

Open Energy Info (EERE)

Modeling-Computer Simulations At U.S. West Region Modeling-Computer Simulations At U.S. West Region (Laney, 2005) Exploration Activity Details Location U.S. West Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful regional reconnaissance DOE-funding Unknown Notes Characterization and Conceptual Modeling of Magmatically-Heated and Deep-Circulation, High-Temperature Hydrothermal Systems in the Basin and Range and Cordilleran United States, Moore, Nash, Nemcok, Lutz, Norton, Kaspereit, Berard, van de Putte, Johnson and Deymonaz. Utilizing a wealth of formerly proprietary subsurface samples and datasets for exemplary high-temperature western U.S. geothermal systems, develop and publish detailed and refined new conceptual and numerical hydrothermal-history models of fundamental scientific import but, more importantly, of use to

13

Modeling-Computer Simulations At Valles Caldera - Sulphur Springs Area  

Open Energy Info (EERE)

Wilt & Haar, 1986) Wilt & Haar, 1986) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Valles Caldera - Sulphur Springs Area (Wilt & Haar, 1986) Exploration Activity Details Location Valles Caldera - Sulphur Springs Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not indicated DOE-funding Unknown Notes A computer program capable of two-dimensional modeling of gravity data was used in interpreting gravity observations along profiles A--A' and B--B' (Talwani et al., 1959). Densities of 2.12, 2.40, and 2.65 g/cm a were used for modeling the near-surface caldera fill, the underlying volcanics, and the basement sections, respectively (Fig. 8). Although correlation with well data was done whenever possible, there is some uncertainty to the

14

Modeling-Computer Simulations At Yellowstone Region (Laney, 2005) | Open  

Open Energy Info (EERE)

Laney, 2005) Laney, 2005) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Yellowstone Region (Laney, 2005) Exploration Activity Details Location Yellowstone Caldera Geothermal Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful regional reconnaissance DOE-funding Unknown Notes Localized Strain as a Discriminator of Hidden Geothermal Systems, Vasco and Foxall, 2005. Recent work has focused on (1) collaborating with Alessandro Ferretti to use Permanent Scatterer (PS) InSAR data to infer strain at depth, (2) working with Lane Johnson to develop a dynamic faulting model, and (3) acquiring InSAR data for the region surrounding the Dixie Valley fault zone in collaboration with Dr. William Foxall of LLNL. The InSAR data

15

Modeling-Computer Simulations At Valles Caldera - Sulphur Springs Area  

Open Energy Info (EERE)

Roberts, Et Al., 1995) Roberts, Et Al., 1995) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Valles Caldera - Sulphur Springs Area (Roberts, Et Al., 1995) Exploration Activity Details Location Valles Caldera - Sulphur Springs Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful DOE-funding Unknown Notes Modeling of the amplitude data, using the Aki-Lamer method, confirmed that this anomaly exists and we estimated quantitative parameters defining it. All model parameters were physically meaningful except for one. The value for Q inside the anomaly, required to explain the data, was unrealistically low. This was probably due to the inability to include additional structural complexity within the low-Q zone that would account for a

16

Modeling-Computer Simulations At Dixie Valley Geothermal Field Area  

Open Energy Info (EERE)

Dixie Valley Geothermal Field Area Dixie Valley Geothermal Field Area (Kennedy & Van Soest, 2006) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Dixie Valley Geothermal Field Area (Kennedy & Van Soest, 2006) Exploration Activity Details Location Dixie Valley Geothermal Field Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness could be useful with more improvements DOE-funding Unknown Notes Using a simple one-dimensional steady-state fluid flow model, the helium content and isotopic composition imply vertical fluid flow rates from the mantle of _7 mm/yr. This is a strict lower limit to the fluid flow rate: the one-dimensional model does not consider diffusive re-distribution of helium or mixing with water containing only a crustal helium component and

17

Modeling-Computer Simulations At Central Nevada Seismic Zone Region  

Open Energy Info (EERE)

Central Nevada Seismic Zone Region Central Nevada Seismic Zone Region (Blackwell, Et Al., 2003) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Central Nevada Seismic Zone Region (Blackwell, Et Al., 2003) Exploration Activity Details Location Central Nevada Seismic Zone Geothermal Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful DOE-funding Unknown Notes Developed natural state mass and energy transport fluid flow models of generic Basin and Range systems based on Dixie Valley data that help to understand the nature of large scale constraints on the location and characteristics of the geothermal systems References D. D. Blackwell, K. W. Wisian, M. C. Richards, Mark Leidig, Richard Smith, Jason McKenna (2003) Geothermal Resource Analysis And Structure Of

18

Modeling-Computer Simulations At Raft River Geothermal Area (1979) | Open  

Open Energy Info (EERE)

Jump to: navigation, search Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Raft River Geothermal Area (1979) Exploration Activity Details Location Raft River Geothermal Area Exploration Technique Modeling-Computer Simulations Activity Date 1979 Usefulness useful DOE-funding Unknown Exploration Basis To evaluate the hydrodynamics of the unconfined aquifer. Notes This study covers about 1000 mi2 (2600 km2) of the southern Raft River drainage basin in south-central Idaho and northwest Utah. The main area of interest, approximately 200 mi2 (520 km2) of semiarid agricultural and rangeland in the southern Raft River Valley that includes the known Geothermal Resource Area near Bridge, Idaho, was modelled numerically. Computed and estimated transmissivity values range from 1200 ft2 per day

19

Modeling-Computer Simulations At Northern Basin & Range Region (Pritchett,  

Open Energy Info (EERE)

Modeling-Computer Simulations At Northern Basin & Range Region (Pritchett, Modeling-Computer Simulations At Northern Basin & Range Region (Pritchett, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Northern Basin & Range Region (Pritchett, 2004) Exploration Activity Details Location Northern Basin and Range Geothermal Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not indicated DOE-funding Unknown References J. W. Pritchett (2004) Finding Hidden Geothermal Resources In The Basin And Range Using Electrical Survey Techniques- A Computational Feasibility Study Retrieved from "http://en.openei.org/w/index.php?title=Modeling-Computer_Simulations_At_Northern_Basin_%26_Range_Region_(Pritchett,_2004)&oldid=401423"

20

Modeling-Computer Simulations At Northern Basin & Range Region (Biasi, Et  

Open Energy Info (EERE)

Modeling-Computer Simulations At Northern Basin & Range Region (Biasi, Et Modeling-Computer Simulations At Northern Basin & Range Region (Biasi, Et Al., 2009) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Northern Basin & Range Region (Biasi, Et Al., 2009) Exploration Activity Details Location Northern Basin and Range Geothermal Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful regional reconnaissance DOE-funding Unknown References Glenn Biasi, Leiph Preston, Ileana Tibuleac (2009) Body Wave Tomography For Regional Scale Assessment Of Geothermal Indicators In The Western Great Basin Retrieved from "http://en.openei.org/w/index.php?title=Modeling-Computer_Simulations_At_Northern_Basin_%26_Range_Region_(Biasi,_Et_Al.,_2009)&oldid=40142

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Modeling-Computer Simulations At Nw Basin & Range Region (Biasi, Et Al.,  

Open Energy Info (EERE)

Biasi, Et Al., Biasi, Et Al., 2009) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Nw Basin & Range Region (Biasi, Et Al., 2009) Exploration Activity Details Location Northwest Basin and Range Geothermal Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful regional reconnaissance DOE-funding Unknown References Glenn Biasi, Leiph Preston, Ileana Tibuleac (2009) Body Wave Tomography For Regional Scale Assessment Of Geothermal Indicators In The Western Great Basin Retrieved from "http://en.openei.org/w/index.php?title=Modeling-Computer_Simulations_At_Nw_Basin_%26_Range_Region_(Biasi,_Et_Al.,_2009)&oldid=401461" Categories: Exploration Activities DOE Funded

22

Modeling-Computer Simulations At Chocolate Mountains Area (Alm, Et Al.,  

Open Energy Info (EERE)

Modeling-Computer Simulations At Chocolate Mountains Area (Alm, Et Al., Modeling-Computer Simulations At Chocolate Mountains Area (Alm, Et Al., 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Chocolate Mountains Area (Alm, Et Al., 2010) Exploration Activity Details Location Chocolate Mountains Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful DOE-funding Unknown Notes "Shallow temperature gradient drilling began at the CMAGR in January of 2010. 13 temperature gradient holes were completed to a depth of 500' below ground surface. Sites were selected based on the compilation of previous exploration and resulting data is being integrated into the most recent geologic model. This model will form the basis for the selection of a

23

Modeling-Computer Simulations At Cove Fort Area (Toksoz, Et Al, 2010) |  

Open Energy Info (EERE)

Modeling-Computer Simulations At Cove Fort Area (Toksoz, Et Al, 2010) Modeling-Computer Simulations At Cove Fort Area (Toksoz, Et Al, 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Cove Fort Area (Toksoz, Et Al, 2010) Exploration Activity Details Location Cove Fort Geothermal Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not indicated DOE-funding Unknown Notes We have collected various geophysical data around the geothermal field, including heat flow, gravity, MT, seismic surface wave phase and group velocity maps, seismic body wave travel time data and full seismic waveforms. All of these geophysical data sets have different strengths on characterizing subsurface structures and properties. Combining these data through a coordinated analysis and, when possible, by joint inversion

24

Modeling-Computer Simulations At Coso Geothermal Area (1980) | Open Energy  

Open Energy Info (EERE)

Modeling-Computer Simulations At Coso Geothermal Area (1980) Modeling-Computer Simulations At Coso Geothermal Area (1980) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Coso Geothermal Area (1980) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Modeling-Computer Simulations Activity Date 1980 Usefulness useful DOE-funding Unknown Exploration Basis Estimate thermal regime and potential of the system Notes A three-dimensional generalized linear inversion of the delta t* observations was performed using a three-layer model. A shallow zone of high attenuation exists within the upper 5 km in a region bounded by Coso Hot Springs, Devils Kitchen, and Sugarloaf Mountain probably corresponding to a shallow vapor liquid mixture or "lossy" near surface lithology.

25

Modeling-Computer Simulations At Coso Geothermal Area (1999) | Open Energy  

Open Energy Info (EERE)

Modeling-Computer Simulations At Coso Geothermal Area (1999) Modeling-Computer Simulations At Coso Geothermal Area (1999) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Coso Geothermal Area (1999) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Modeling-Computer Simulations Activity Date 1999 Usefulness not indicated DOE-funding Unknown Exploration Basis To analyze attenuation and source properties Notes A multiple-empirical Green's function method was used to determine source properties of small (M -0.4 to 1.3) earthquakes and P-wave and S-wave attenuation at the Coso Geothermal Field. Source properties of a previously identified set of clustered events from the Coso geothermal region are first analyzed using an empirical Green's function (EGF) method.

26

Modeling-Computer Simulations At Nw Basin & Range Region (Laney, 2005) |  

Open Energy Info (EERE)

Modeling-Computer Simulations At Nw Basin & Range Region (Laney, 2005) Modeling-Computer Simulations At Nw Basin & Range Region (Laney, 2005) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Nw Basin & Range Region (Laney, 2005) Exploration Activity Details Location Northwest Basin and Range Geothermal Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not indicated DOE-funding Unknown Notes Assembling Crustal Geophysical Data for Geothermal Exploration in the Great Basin, Louie and Coolbaugh. We have compiled velocity information from sources in the literature, results of previous seismic experiments and earthquake-monitoring projects, and data donated from mining, geothermal, and petroleum companies. We also collected (May 2002 and August 2004) two

27

Modeling-Computer Simulations At Coso Geothermal Area (2000) | Open Energy  

Open Energy Info (EERE)

Modeling-Computer Simulations At Coso Geothermal Area (2000) Modeling-Computer Simulations At Coso Geothermal Area (2000) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Coso Geothermal Area (2000) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Modeling-Computer Simulations Activity Date 2000 Usefulness not indicated DOE-funding Unknown Exploration Basis Model ground subsidence using observations of satellite radar interferometry Notes The InSAR displacement data was inverted for the positions, geometry, and relative strengths of the deformation sources at depth using a nonlinear least squares minimization algorithm. Elastic solutions were used for a prolate uniformly pressurized spheroidal cavity in a semi-infinite body as

28

Modeling-Computer Simulations At Fish Lake Valley Area (Deymonaz, Et Al.,  

Open Energy Info (EERE)

Modeling-Computer Simulations At Fish Lake Valley Area (Deymonaz, Et Al., Modeling-Computer Simulations At Fish Lake Valley Area (Deymonaz, Et Al., 2008) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Fish Lake Valley Area (Deymonaz, Et Al., 2008) Exploration Activity Details Location Fish Lake Valley Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful DOE-funding Unknown Notes (4) synthesis of geologic mapping results and lithologic logs for 3_D geologic characterization of the prospect area; (5) compilation of relevant data from the foregoing sub_activities into a Geographic Information Systems (GIS) database for visualization and mapping, and to facilitate the development of an exploration model; and (6) development of a refined

29

Modeling-Computer Simulations At Akutan Fumaroles Area (Kolker, Et Al.,  

Open Energy Info (EERE)

Modeling-Computer Simulations At Akutan Fumaroles Area (Kolker, Et Al., Modeling-Computer Simulations At Akutan Fumaroles Area (Kolker, Et Al., 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Akutan Fumaroles Area (Kolker, Et Al., 2010) Exploration Activity Details Location Akutan Fumaroles Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful DOE-funding Unknown Notes "Conceptual Model: Based on conceptual models built primarily from MT and geochemical datasets, it appears that development of the Akutan geothermal resource for power and/or direct use may be feasible. These datasets point to a shallow, tabular aquifer(s) of 155-180degrees C (i.e., "outflow zone") and a deeper, hotter resource of >220degrees C (i.e., "upflow zone") that

30

Modeling-Computer Simulations At Valles Caldera - Redondo Area (Roberts, Et  

Open Energy Info (EERE)

Modeling-Computer Simulations At Valles Caldera - Redondo Area (Roberts, Et Modeling-Computer Simulations At Valles Caldera - Redondo Area (Roberts, Et Al., 1995) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Valles Caldera - Redondo Area (Roberts, Et Al., 1995) Exploration Activity Details Location Valles Caldera - Redondo Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful DOE-funding Unknown Notes Modeling of the amplitude data, using the Aki-Lamer method, confirmed that this anomaly exists and we estimated quantitative parameters defining it. All model parameters were physically meaningful except for one. The value for Q inside the anomaly, required to explain the data, was unrealistically low. This was probably due to the inability to include additional

31

Modeling-Computer Simulations At San Juan Volcanic Field Area (Clarkson &  

Open Energy Info (EERE)

Modeling-Computer Simulations At San Juan Volcanic Field Area (Clarkson & Modeling-Computer Simulations At San Juan Volcanic Field Area (Clarkson & Reiter, 1987) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At San Juan Volcanic Field Area (Clarkson & Reiter, 1987) Exploration Activity Details Location San Juan Volcanic Field Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful DOE-funding Unknown Notes In this study we combine thermal maturation models, based on the level of maturation of the Fruitland Formation coals, and time-dependet temperature models, based on heat-flow data in the San Juan region, to further investigate both the thermal history of the region and the nature of the influence of the San Juan volcanic field thermal source on the thermal

32

Modeling-Computer Simulations At Hawthorne Area (Lazaro, Et Al., 2010) |  

Open Energy Info (EERE)

Modeling-Computer Simulations At Hawthorne Area (Lazaro, Et Al., 2010) Modeling-Computer Simulations At Hawthorne Area (Lazaro, Et Al., 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Hawthorne Area (Lazaro, Et Al., 2010) Exploration Activity Details Location Hawthorne Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not indicated DOE-funding Unknown Notes The Navy GPO has contracted the University of Nevada Reno Great Basin for Center for Geothermal Research to conduct additional field exploration at HAD. The tasks required by the Navy range from field mapping and water sampling; detailed mapping, to low angle sun photo interpretations, trenching, to 3-D seismic interpretations and modeling. References Michael Lazaro, Chris Page, Andy Tiedeman, Andrew Sabin, Steve

33

Modeling-Computer Simulations At Raft River Geothermal Area (1977) | Open  

Open Energy Info (EERE)

Raft River Geothermal Area (1977) Raft River Geothermal Area (1977) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Raft River Geothermal Area (1977) Exploration Activity Details Location Raft River Geothermal Area Exploration Technique Modeling-Computer Simulations Activity Date 1977 Usefulness not indicated DOE-funding Unknown Exploration Basis Simulate reservoir performance Notes Computer models describing both the transient reservoir pressure behavior and the time dependent temperature response of the wells were developed. A horizontal, two-dimensional, finite-difference model for calculating pressure effects was constructed to simulate reservoir performance. Vertical, two-dimensional, finite-difference, axisymmetric models for each

34

Modeling-Computer Simulations At Obsidian Cliff Area (Hulen, Et Al., 2003)  

Open Energy Info (EERE)

Obsidian Cliff Area (Hulen, Et Al., 2003) Obsidian Cliff Area (Hulen, Et Al., 2003) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Obsidian Cliff Area (Hulen, Et Al., 2003) Exploration Activity Details Location Obsidian Cliff Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful DOE-funding Unknown References Jeff Hulen, Denis Norton, Dennis Kaspereit, Larry Murray, Todd van de Putte, Melinda Wright (2003) Geology And A Working Conceptual Model Of The Obsidian Butte (Unit 6) Sector Of The Salton Sea Geothermal Field, California Retrieved from "http://en.openei.org/w/index.php?title=Modeling-Computer_Simulations_At_Obsidian_Cliff_Area_(Hulen,_Et_Al.,_2003)&oldid=388945" Category: Exploration

35

Modeling-Computer Simulations At Long Valley Caldera Area (Pribnow, Et Al.,  

Open Energy Info (EERE)

2003) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Long Valley Caldera Area (Pribnow, Et Al., 2003) Exploration Activity Details Location Long Valley Caldera Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not indicated DOE-funding Unknown Notes Several fluid-flow models presented regarding the Long Valley Caldera. At shallow depths in the caldera References Daniel F. C. Pribnow, Claudia Schutze, Suzanne J. Hurter, Christina Flechsig, John H. Sass (2003) Fluid Flow In The Resurgent Dome Of Long Valley Caldera- Implications From Thermal Data And Deep Electrical Sounding Retrieved from "http://en.openei.org/w/index.php?title=Modeling-Computer_Simulations_At_Long_Valley_Caldera_Area_(Pribnow,_Et_Al.,_2003)&oldid=389388

36

Modeling-Computer Simulations At Fenton Hill Hdr Geothermal Area (Heiken &  

Open Energy Info (EERE)

Heiken & Heiken & Goff, 1983) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Fenton Hill Hdr Geothermal Area (Heiken & Goff, 1983) Exploration Activity Details Location Fenton Hill Hdr Geothermal Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not indicated DOE-funding Unknown Notes Development of a geologically-based model of the thermal and hydrothermal potential of the Fenton Hill HDR area. References Grant Heiken, Fraser Goff (1983) Hot Dry Rock Geothermal Energy In The Jemez Volcanic Field, New Mexico Retrieved from "http://en.openei.org/w/index.php?title=Modeling-Computer_Simulations_At_Fenton_Hill_Hdr_Geothermal_Area_(Heiken_%26_Goff,_1983)&oldid=511328

37

Modeling-Computer Simulations At General Us Region (Goff & Decker, 1983) |  

Open Energy Info (EERE)

Us Region (Goff & Decker, 1983) Us Region (Goff & Decker, 1983) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At General Us Region (Goff & Decker, 1983) Exploration Activity Details Location General Us Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful DOE-funding Unknown Notes Review and identification of 24 potential sites for EGS development across the U.S., as well as modeling of the representative geologic systems in which promising EGS sites occur. References Fraser Goff, Edward R. Decker (1983) Candidate Sites For Future Hot Dry Rock Development In The United States Retrieved from "http://en.openei.org/w/index.php?title=Modeling-Computer_Simulations_At_General_Us_Region_(Goff_%26_Decker,_1983)&oldid=38761

38

Modeling-Computer Simulations At Geysers Area (Goff & Decker, 1983) | Open  

Open Energy Info (EERE)

Decker, 1983) Decker, 1983) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Geysers Area (Goff & Decker, 1983) Exploration Activity Details Location Geysers Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful DOE-funding Unknown Notes Review and identification of 24 potential sites for EGS development across the U.S., as well as modeling of the representative geologic systems in which promising EGS sites occur. References Fraser Goff, Edward R. Decker (1983) Candidate Sites For Future Hot Dry Rock Development In The United States Retrieved from "http://en.openei.org/w/index.php?title=Modeling-Computer_Simulations_At_Geysers_Area_(Goff_%26_Decker,_1983)&oldid=38676

39

Modeling-Computer Simulations At White Mountains Area (Goff & Decker, 1983)  

Open Energy Info (EERE)

White Mountains Area (Goff & Decker, 1983) White Mountains Area (Goff & Decker, 1983) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At White Mountains Area (Goff & Decker, 1983) Exploration Activity Details Location White Mountains Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful DOE-funding Unknown Notes Review and identification of 24 potential sites for EGS development across the U.S., as well as modeling of the representative geologic systems in which promising EGS sites occur. References Fraser Goff, Edward R. Decker (1983) Candidate Sites For Future Hot Dry Rock Development In The United States Retrieved from "http://en.openei.org/w/index.php?title=Modeling-Computer_Simulations_At_White_Mountains_Area_(Goff_%26_Decker,_1983)&oldid=387355"

40

Modeling-Computer Simulations At Fenton Hill Hdr Geothermal Area (Goff &  

Open Energy Info (EERE)

Decker, 1983) Decker, 1983) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Fenton Hill Hdr Geothermal Area (Goff & Decker, 1983) Exploration Activity Details Location Fenton Hill Hdr Geothermal Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful DOE-funding Unknown Notes Review and identification of 24 potential sites for EGS development across the U.S., as well as modeling of the representative geologic systems in which promising EGS sites occur. References Fraser Goff, Edward R. Decker (1983) Candidate Sites For Future Hot Dry Rock Development In The United States Retrieved from "http://en.openei.org/w/index.php?title=Modeling-Computer_Simulations_At_Fenton_Hill_Hdr_Geothermal_Area_(Goff_%26_Decker,_1983)&oldid=511326"

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Modeling-Computer Simulations At Nevada Test And Training Range Area  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » Modeling-Computer Simulations At Nevada Test And Training Range Area (Sabin, Et Al., 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Nevada Test And Training Range Area (Sabin, Et Al., 2004) Exploration Activity Details Location Nevada Test And Training Range Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not indicated DOE-funding Unknown Notes Nellis Air Force Range (NAFR) occupies over 3 million acres in southern Nevada (Figure 1). We recently assessed potential utility-grade geothermal

42

Modeling-Computer Simulations At Nw Basin & Range Region (Blackwell, Et  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » Modeling-Computer Simulations At Nw Basin & Range Region (Blackwell, Et Al., 2003) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Nw Basin & Range Region (Blackwell, Et Al., 2003) Exploration Activity Details Location Northwest Basin and Range Geothermal Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful DOE-funding Unknown Notes Developed natural state mass and energy transport fluid flow models of generic Basin and Range systems based on Dixie Valley data that help to

43

Modeling-Computer Simulations At Walker-Lane Transitional Zone Region  

Open Energy Info (EERE)

Modeling-Computer Simulations At Walker-Lane Modeling-Computer Simulations At Walker-Lane Transitional Zone Region (Laney, 2005) Exploration Activity Details Location Walker-Lane Transition Zone Geothermal Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not indicated DOE-funding Unknown Notes Assembling Crustal Geophysical Data for Geothermal Exploration in the Great Basin, Louie and Coolbaugh. We have compiled velocity information from sources in the literature, results of previous seismic experiments and earthquake-monitoring projects, and data donated from mining, geothermal, and petroleum companies. We also collected (May 2002 and August 2004) two new crustal refraction profiles across western Nevada and the northern and central Sierra. These sections had not been well characterized previously.

44

Modeling-Computer Simulations At Raft River Geothermal Area (1980) | Open  

Open Energy Info (EERE)

80) 80) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Raft River Geothermal Area (1980) Exploration Activity Details Location Raft River Geothermal Area Exploration Technique Modeling-Computer Simulations Activity Date 1980 Usefulness not indicated DOE-funding Unknown Exploration Basis From refined estimates of reservoir coefficients better predictions of interference effects and long-term drawdown in the wells can be made. Notes Analytic methods have been used during reservoir testing to calculate reservoir coefficients. However, anisotropy of the reservoir due to fractures has not been taken into account in these calculations and estimates of these coefficients need to be refined. In conjunction with the

45

Numerical simulation of hydraulic fracturing  

E-Print Network (OSTI)

NUMERICAL SIMULATION OF HYDRAULIC FRACTURING A Thesis by JOSEPH BARNES WARNER Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1987 Maj or Subj ect...: Petroleum Engineering NUMERICAL SIMULATION OF HYDRAULIC FRACTURING A Thesis by JOSEPH BARNES WARNER Approved as to style and content by: S. A. Holditch (Chairman of Committee) D. D. Van Fleet (member) J. E. Russell (m be ) W. D. Von onten ( ead...

Warner, Joseph Barnes

2012-06-07T23:59:59.000Z

46

Modeling-Computer Simulations At Northern Basin & Range Region (Blackwell,  

Open Energy Info (EERE)

Northern Basin & Northern Basin & Range Region (Blackwell, Et Al., 2003) Exploration Activity Details Location Northern Basin and Range Geothermal Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful DOE-funding Unknown Notes Developed natural state mass and energy transport fluid flow models of generic Basin and Range systems based on Dixie Valley data that help to understand the nature of large scale constraints on the location and characteristics of the geothermal systems References D. D. Blackwell, K. W. Wisian, M. C. Richards, Mark Leidig, Richard Smith, Jason McKenna (2003) Geothermal Resource Analysis And Structure Of Basin And Range Systems, Especially Dixie Valley Geothermal Field, Nevada Retrieved from "http://en.openei.org/w/index.php?title=Modeling-Computer_Simulations_At_Northern_Basin_%26_Range_Region_(Blackwell,_Et_Al.,_2003)&oldid=401422

47

Modeling-Computer Simulations At Kilauea East Rift Area (Rudman & Epp,  

Open Energy Info (EERE)

Rudman & Epp, Rudman & Epp, 1983) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Kilauea East Rift Area (Rudman & Epp, 1983) Exploration Activity Details Location Kilauea East Rift Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful DOE-funding Unknown Notes Three models were generated: a constant temperature source from a vertical dike; a constant heat-generating magma chamber; and a transient heat source from a tapered vertical dike. Fair correlation is obtained between the HGP-A well temperature and the tapered dike 125 years after it is injected with an initial (transient) 1200degrees C temperature. Results provide background information from which to evaluate the importance of water

48

Modeling-Computer Simulations At Long Valley Caldera Area (Farrar, Et Al.,  

Open Energy Info (EERE)

3) 3) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Long Valley Caldera Area (Farrar, Et Al., 2003) Exploration Activity Details Location Long Valley Caldera Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful DOE-funding Unknown Notes Modeling of both deformation and microgravity data now suggests that (1) there are two inflation sources beneath the caldera, a shallower source 7^10 km beneath the resurgent dome and a deeper source V15 km beneath the caldera's south moat and (2) the shallower source may contain components of magmatic brine and gas. At shallow depths in the caldera References Christopher D. Farrar, Michael L. Sorey, Evelyn Roeloffs, Devin L.

49

Modeling-Computer Simulations At Valles Caldera - Redondo Area (Wilt &  

Open Energy Info (EERE)

Redondo Area (Wilt & Redondo Area (Wilt & Haar, 1986) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Valles Caldera - Redondo Area (Wilt & Haar, 1986) Exploration Activity Details Location Valles Caldera - Redondo Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness could be useful with more improvements DOE-funding Unknown Notes A computer program capable of two-dimensional modeling of gravity data was used in interpreting gravity observations along profiles A--A' and B--B' (Talwani et al., 1959). Densities of 2.12, 2.40, and 2.65 g/cm a were used for modeling the near-surface caldera fill, the underlying volcanics, and the basement sections, respectively (Fig. 8). Although correlation with

50

Numerical simulation of electrokinetically driven micro flows  

E-Print Network (OSTI)

Spectral element based numerical solvers are developed to simulate electrokinetically driven flows for micro-fluidic applications. Based on these numerical solvers, basic phenomena and devices for electrokinetic applications in micro and nano flows...

Hahm, Jungyoon

2005-11-01T23:59:59.000Z

51

Threedimensional numerical simulation for various geometries  

E-Print Network (OSTI)

Three­dimensional numerical simulation for various geometries of solid oxide fuel cells J.R. Ferguson 1 , J.M. Fiard 2 , and R. Herbin 3 Abstract A 3D mathematical model of a Solid Oxide Fuel Cell modelling and numerical simulation of natural gas­fed solid oxide cells (Solid Oxide Fuel Cell, SOFC

Herbin, Raphaèle

52

Numerical Simulation of Cooling Gas Injection Using  

E-Print Network (OSTI)

Numerical Simulation of Cooling Gas Injection Using Adaptive Multiscale Techniques Wolfgang Dahmen: finite volume method, film cooling, cooling gas injection, multiscale techniques, grid adaptation AMS@igpm.rwth-aachen.de (Thomas Gotzen) #12;Numerical simulation of cooling gas injection using adaptive multiscale techniques

53

Comparing Aerodynamic Models for Numerical Simulation of  

E-Print Network (OSTI)

Comparing Aerodynamic Models for Numerical Simulation of Dynamics and Control of Aircraft and simulation of aircraft, yet other aerodynamics models exist that can provide more accurate results for certain simulations without a large increase in computational time. In this paper, sev- eral aerodynamics

Peraire, Jaime

54

Numerical Simulation of Surfactant-Polymer Flooding  

Science Journals Connector (OSTI)

We propose a mathematical model (numerical simulation) of surfactant-polymer flooding for a three-phase six-component system. ... model takes into account various phenomena inherent to flooding, the effect of sur...

Baoguang Jin; Hanqiao Jiang; Xiansong Zhang

2014-03-01T23:59:59.000Z

55

NUMERICAL SIMULATIONS OF CHROMOSPHERIC MICROFLARES  

SciTech Connect

With gravity, ionization, and radiation being considered, we perform 2.5 dimensional (2.5D) compressible resistive magnetohydrodynamic (MHD) simulations of chromospheric magnetic reconnection using the CIP-MOCCT scheme. The temperature distribution of the quiet-Sun atmospheric model VALC and the helium abundance (10%) are adopted. Our 2.5D MHD simulation reproduces qualitatively the temperature enhancement observed in chromospheric microflares. The temperature enhancement DELTAT is demonstrated to be sensitive to the background magnetic field, whereas the total evolution time DELTAt is sensitive to the magnitude of the anomalous resistivity. Moreover, we found a scaling law, which is described as DELTAT/DELTAt {approx} n{sub H} {sup -1.5} B {sup 2.1}eta{sub 0} {sup 0.88}. Our results also indicate that the velocity of the upward jet is much greater than that of the downward jet, and the X-point may move up or down.

Jiang, R. L.; Fang, C.; Chen, P. F., E-mail: fangc@nju.edu.c [Department of Astronomy, Nanjing University, Nanjing 210093 (China)

2010-02-20T23:59:59.000Z

56

Numerical Simulations of Bouncing Jets  

E-Print Network (OSTI)

Bouncing jets are fascinating phenomenons occurring under certain conditions when a jet impinges on a free surface. This effect is observed when the fluid is Newtonian and the jet falls in a bath undergoing a solid motion. It occurs also for non-Newtonian fluids when the jets falls in a vessel at rest containing the same fluid. We investigate numerically the impact of the experimental setting and the rheological properties of the fluid on the onset of the bouncing phenomenon. Our investigations show that the occurrence of a thin lubricating layer of air separating the jet and the rest of the liquid is a key factor for the bouncing of the jet to happen. The numerical technique that is used consists of a projection method for the Navier-Stokes system coupled with a level set formulation for the representation of the interface. The space approximation is done with adaptive finite elements. Adaptive refinement is shown to be very important to capture the thin layer of air that is responsible for the bouncing.

Bonito, Andrea; Lee, Sanghyun

2015-01-01T23:59:59.000Z

57

SciTech Connect: Development of Numerical Simulation Capabilities...  

Office of Scientific and Technical Information (OSTI)

Development of Numerical Simulation Capabilities for In Situ Heating of Oil Shale Citation Details In-Document Search Title: Development of Numerical Simulation Capabilities for In...

58

Numerical Simulations of Hyperfine Transitions of Antihydrogen  

E-Print Network (OSTI)

One of the ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons) collaboration's goals is the measurement of the ground state hyperfine transition frequency in antihydrogen, the antimatter counterpart of one of the best known systems in physics. This high precision experiment yields a sensitive test of the fundamental symmetry of CPT. Numerical simulations of hyperfine transitions of antihydrogen atoms have been performed providing information on the required antihydrogen events and the achievable precision.

Kolbinger, B; Diermaier, M; Lehner, S; Malbrunot, C; Massiczek, O; Sauerzopf, C; Simon, M C; Widmann, E

2015-01-01T23:59:59.000Z

59

Direct numerical simulation of turbulent reacting flows  

SciTech Connect

The development of turbulent combustion models that reflect some of the most important characteristics of turbulent reacting flows requires knowledge about the behavior of key quantities in well defined combustion regimes. In turbulent flames, the coupling between the turbulence and the chemistry is so strong in certain regimes that is is very difficult to isolate the role played by one individual phenomenon. Direct numerical simulation (DNS) is an extremely useful tool to study in detail the turbulence-chemistry interactions in certain well defined regimes. Globally, non-premixed flames are controlled by two limiting cases: the fast chemistry limit, where the turbulent fluctuations. In between these two limits, finite-rate chemical effects are important and the turbulence interacts strongly with the chemical processes. This regime is important because industrial burners operate in regimes in which, locally the flame undergoes extinction, or is at least in some nonequilibrium condition. Furthermore, these nonequilibrium conditions strongly influence the production of pollutants. To quantify the finite-rate chemistry effect, direct numerical simulations are performed to study the interaction between an initially laminar non-premixed flame and a three-dimensional field of homogeneous isotropic decaying turbulence. Emphasis is placed on the dynamics of extinction and on transient effects on the fine scale mixing process. Differential molecular diffusion among species is also examined with this approach, both for nonreacting and reacting situations. To address the problem of large-scale mixing and to examine the effects of mean shear, efforts are underway to perform large eddy simulations of round three-dimensional jets.

Chen, J.H. [Sandia National Laboratories, Livermore, CA (United States)

1993-12-01T23:59:59.000Z

60

Collisionless microinstabilities in stellarators. II. Numerical simulations  

SciTech Connect

Microinstabilities exhibit a rich variety of behavior in stellarators due to the many degrees of freedom in the magnetic geometry. It has recently been found that certain stellarators (quasi-isodynamic ones with maximum-J geometry) are partly resilient to trapped-particle instabilities, because fast-bouncing particles tend to extract energy from these modes near marginal stability. In reality, stellarators are never perfectly quasi-isodynamic, and the question thus arises whether they still benefit from enhanced stability. Here, the stability properties of Wendelstein 7-X and a more quasi-isodynamic configuration, QIPC, are investigated numerically and compared with the National Compact Stellarator Experiment and the DIII-D tokamak. In gyrokinetic simulations, performed with the gyrokinetic code GENE in the electrostatic and collisionless approximation, ion-temperature-gradient modes, trapped-electron modes, and mixed-type instabilities are studied. Wendelstein 7-X and QIPC exhibit significantly reduced growth rates for all simulations that include kinetic electrons, and the latter are indeed found to be stabilizing in the energy budget. These results suggest that imperfectly optimized stellarators can retain most of the stabilizing properties predicted for perfect maximum-J configurations.

Proll, J. H. E.; Xanthopoulos, P.; Helander, P. [Max-Planck-Institut fr Plasmaphysik, EURATOM Association, Teilinstitut Greifswald, Wendelsteinstrae 1, 17491 Greifswald, Germany and Max-Planck/Princeton Research Center for Plasma Physics, 17491 Greifswald (Germany)] [Max-Planck-Institut fr Plasmaphysik, EURATOM Association, Teilinstitut Greifswald, Wendelsteinstrae 1, 17491 Greifswald, Germany and Max-Planck/Princeton Research Center for Plasma Physics, 17491 Greifswald (Germany)

2013-12-15T23:59:59.000Z

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Numerical simulation of wind effects: a probabilistic perspective Ahsan Kareem  

E-Print Network (OSTI)

Numerical simulation of wind effects: a probabilistic perspective Ahsan Kareem NatHaz Modeling Laboratory, University of Notre Dame, Notre Dame, IN 46556 ABSTRACT: Numerical simulations of wind loads and their effects are critical in the design of structures to ensure their safety under winds. The simulations range

Kareem, Ahsan

62

Numerical Simulation Methods Used at VNIIEF for Numerical Simulation Methods Used at VNIIEF for  

National Nuclear Security Administration (NNSA)

61 61 Numerical Simulation Methods Used at VNIIEF for Numerical Simulation Methods Used at VNIIEF for Multidimensional Radiation and Particle Transport Problems Multidimensional Radiation and Particle Transport Problems R.M. R.M. Shagaliev Shagaliev RFNC-VNIIEF, 607190, RFNC-VNIIEF, 607190, Sarov Sarov, , Nizhni Nizhni Novgorod region Novgorod region Joint Russian-American Five-Laboratory Conference on Computation Joint Russian-American Five-Laboratory Conference on Computation Mathematics|Physics Mathematics|Physics 19-23 June 2005, 19-23 June 2005, Crowne Crowne Plaza, Vienna, Austria Plaza, Vienna, Austria Russian Federal Nuclear Center - VNIIEF Institute of Theoretical Institute of Theoretical and Mathematical and Mathematical Physics Physics 2 of 61 Abstract

63

Numerical simulations of a vertical tail of a commercial aircraft...  

NLE Websites -- All DOE Office Websites (Extended Search)

of a commercial aircraft with active flow control Authors: Rasquin, M., Martin, J., Jansen, K. A series of numerical simulations of a realistic vertical tail of a commercial...

64

Direct Numerical Simulations and Robust Predictions of Cloud...  

NLE Websites -- All DOE Office Websites (Extended Search)

the center of the bubble cloud. Credit: Computational Science and Engineering Laboratory, ETH Zurich, Switzerland Direct Numerical Simulations and Robust Predictions of Cloud...

65

Direct numerical simulations of aeolian sand ripples  

E-Print Network (OSTI)

Aeolian sand beds exhibit regular patterns of ripples resulting from the interaction between topography and sediment transport. Their characteristics have been so far related to reptation transport caused by the impacts on the ground of grains entrained by the wind into saltation. By means of direct numerical simulations of grains interacting with a wind flow, we show that the instability turns out to be driven by resonant grain trajectories, whose length is close to a ripple wavelength and whose splash leads to a mass displacement towards the ripple crests. The pattern selection results from a compromise between this destabilizing mechanism and a diffusive downslope transport which stabilizes small wavelengths. The initial wavelength is set by the ratio of the sediment flux and the erosion/deposition rate, a ratio which increases linearly with the wind velocity. We show that this scaling law, in agreement with experiments, originates from an interfacial layer separating the saltation zone from the static sand bed, where momentum transfers are dominated by mid-air collisions. Finally, we provide quantitative support for the use the propagation of these ripples as a proxy for remote measurements of sediment transport.

Orencio Duran; Philippe Claudin; Bruno Andreotti

2014-11-07T23:59:59.000Z

66

NUMERICAL SIMULATIONS OF DRIVEN RELATIVISTIC MAGNETOHYDRODYNAMIC TURBULENCE  

SciTech Connect

A wide variety of astrophysical phenomena involve the flow of turbulent magnetized gas with relativistic velocity or energy density. Examples include gamma-ray bursts, active galactic nuclei, pulsars, magnetars, micro-quasars, merging neutron stars, X-ray binaries, some supernovae, and the early universe. In order to elucidate the basic properties of the relativistic magnetohydrodynamical (RMHD) turbulence present in these systems, we present results from numerical simulations of fully developed driven turbulence in a relativistically warm, weakly magnetized and mildly compressible ideal fluid. We have evolved the RMHD equations for many dynamical times on a uniform grid with 1024{sup 3} zones using a high-order Godunov code. We observe the growth of magnetic energy from a seed field through saturation at {approx}1% of the total fluid energy. We compute the power spectrum of velocity and density-weighted velocity U = {rho}{sup 1/3} v and conclude that the inertial scaling is consistent with a slope of -5/3. We compute the longitudinal and transverse velocity structure functions of order p up to 11 and discuss their possible deviation from the expected scaling for non-relativistic media. We also compute the scale-dependent distortion of coherent velocity structures with respect to the local magnetic field, finding a weaker scale dependence than is expected for incompressible non-relativistic flows with a strong mean field.

Zrake, Jonathan; MacFadyen, Andrew I. [Center for Cosmology and Particle Physics, Physics Department, New York University, New York, NY 10003 (United States)

2012-01-01T23:59:59.000Z

67

Numerical simulation of contaminant flow in a wool scour  

Science Journals Connector (OSTI)

Wool scouring is the process of washing dirty wool after shearing. Our model numerically simulates contaminant movement in a wool scour bowl using the advection-dispersion equation. This is the first wool scour model to give time-dependent results and ... Keywords: Finite differences, Numerical simulation, Wool scouring

J. F. Caunce; S. I. Barry; G. N. Mercer; T. R. Marchant

2007-08-01T23:59:59.000Z

68

Numerical Simulation of Wave Loads on Static Offshore Structures  

E-Print Network (OSTI)

Numerical Simulation of Wave Loads on Static Offshore Structures Hrvoje Jasak, Inno Gatin, Vuko Workshop, Cambridge, 30 July 2014 Numerical Simulation of Wave Loads on Static Offshore Structures ­ p. #12 of Wave Loads on Static Offshore Structures ­ p. #12;VOF Free Surface Flow Model Modelling of Free Surface

69

High Order Hybrid Numerical Simulations of Two Dimensional Detonation Waves  

E-Print Network (OSTI)

High Order Hybrid Numerical Simulations of Two Dimensional Detonation Waves Wei Cai Department detonation waves, we have devel- oped a high order numerical scheme suitable for calculating the detailed transverse wave structures of multidimensional detonation waves. The numerical algorithm uses a multi

Cai, Wei

70

In-shock cooling in numerical simulations  

Science Journals Connector (OSTI)

......especially interested in the production of molecular hydrogen, and so we follow the...hydrodynamics|shock waves|methods: numerical| 1 Introduction...the rate of molecular hydrogen (H2) and hydrogen-deuterium (HD) production. These two molecules......

Roger M. Hutchings; Peter A. Thomas

2000-12-11T23:59:59.000Z

71

Numerical techniques of rigid body simulation  

E-Print Network (OSTI)

In recent years, the modeling of physical phenomena has become an integral part of computer applications in diverse areas from engineering to entertainment. This thesis focuses on a particular aspect of this modeling, the simulation of rigid...

Eberle, David Michael

2012-06-07T23:59:59.000Z

72

Numerical Simulation in a Supercirtical CFB Boiler  

Science Journals Connector (OSTI)

The dimension of the hot circulation loop of the supercritical CFB boiler is large, and there are many ... simulation of gas-solid flow in a supercritical CFB boiler was conducted by using FLUENT software. ... th...

Yanjun Zhang; Xiang Gaol; Zhongyang Luo

2010-01-01T23:59:59.000Z

73

Plasma astrophysics in numerical simulations A. Nordlund  

E-Print Network (OSTI)

in periodic domains are discussed. Modifications of the solutions by numerically motivated alterations-excited dynamos were invented by the Danish inventor Søren Hjorth, who received the patent for this discovery industrial importance in producing the most powerful generators at the time, for which he, in turn, received

Brandenburg, Axel

74

Numerical Simulation of the December 26, 2004: Indian Ocean Tsunami  

E-Print Network (OSTI)

Numerical Simulation of the December 26, 2004: Indian Ocean Tsunami J. Asavanant1, M. Ioualalen2, N. Kaewbanjak1, S. Grilli3, P. Watts4, and J. Kirby5 Abstract: The December 26, 2004 tsunami is one of the most

Kirby, James T.

75

Numerical Simulation Study on Transpired Solar Air Collector  

E-Print Network (OSTI)

ICEBO2006, Shenzhen, China Re newable Energy Resources and a Greener Future Vol.VIII-3-4 Numerical Simulation Study on Transpired Solar Air Collector Chongjie Wang Zhenzhong Guan Xueyi Zhao Delin Wang Professor...

Wang, C.; Guan, Z.; Zhao, X.; Wang, D.

2006-01-01T23:59:59.000Z

76

Electrowetting-based microfluidics: mathematical modeling and numerical simulation  

Science Journals Connector (OSTI)

The work presented in this dissertation focuses on the mathematical modeling and numerical simulation of the dynamics of a liquid droplet undergoing electrowetting, or electrowetting-on-dielectrics (EWOD). A mathematical model is formulated for the two-phase ...

Michael Franklin / Ali Nadim

2013-01-01T23:59:59.000Z

77

Asphaltene Deposition in Carbonate Rocks: Experimental Investigation and Numerical Simulation  

Science Journals Connector (OSTI)

Asphaltene Deposition in Carbonate Rocks: Experimental Investigation and Numerical Simulation ... Interfacial tension (IFT) as one of the main properties for efficient CO2 flooding planning in oil reservoirs depends strongly on pressure, temperature, and composition of the reservoir fluids. ...

Shahin Kord; Rohaldin Miri; Shahab Ayatollahi; Mehdi Escrochi

2012-06-20T23:59:59.000Z

78

Effective conductivity of loaded granular materials by numerical simulation  

Science Journals Connector (OSTI)

...studied by numerical simulation. The particles are smooth uniform spheres with...granular assemblages of frictional particles (God- dard et al. 1993, 1994) in...packed granular materials with high particle-to-medium conductivity ratio...

1998-01-01T23:59:59.000Z

79

Numerical simulation for formed projectile of depleted uranium alloy  

Science Journals Connector (OSTI)

The numerical simulation for forming projectile of depleted uranium alloy with the SPH (Smooth Particle Hydrodynamic ... . To describe the deformed behaviors of the depleted uranium alloy under high pressure and ...

Song Shun-cheng; Gao Ping; Cai Hong-nian

2003-09-01T23:59:59.000Z

80

Numerical simulation of laser ignition of a liquid fuel film  

Science Journals Connector (OSTI)

Numerical simulations were used to examine a set of interrelated physicochemical processes involved in the ignition of a liquid fuel film by a low-power laser beam. The delay time of ignition of a liquid fuel fil...

G. V. Kuznetsov; P. A. Strizhak

2010-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

NUMERICAL METHODS FOR THE SIMULATION OF HIGH INTENSITY HADRON SYNCHROTRONS.  

SciTech Connect

Numerical algorithms for PIC simulation of beam dynamics in a high intensity synchrotron on a parallel computer are presented. We introduce numerical solvers of the Laplace-Poisson equation in the presence of walls, and algorithms to compute tunes and twiss functions in the presence of space charge forces. The working code for the simulation here presented is SIMBAD, that can be run as stand alone or as part of the UAL (Unified Accelerator Libraries) package.

LUCCIO, A.; D'IMPERIO, N.; MALITSKY, N.

2005-09-12T23:59:59.000Z

82

Numerical Simulation of a Natural Circulation Steam Generator  

E-Print Network (OSTI)

Numerical Simulation of a Natural Circulation Steam Generator W. Linzer \\Lambda , K. Ponweiser circulation steam generator. We focus on a model with a simple geometry consisting of two vertical pipes properties of water and steam. We present a numerical algorithm based on an explicit upwind discretization

Weinmüller, Ewa B.

83

A Mobile Computing Architecture for Numerical Simulation Cyril Dumont  

E-Print Network (OSTI)

A Mobile Computing Architecture for Numerical Simulation Cyril Dumont Paris 12 University LACL of a numeric computation have to react when their context changes. This paper offers a new architecture, a mobile computing architecture, based on mobile agents and JavaSpace. At the end of this paper, we apply

Paris-Sud XI, Université de

84

DIRECT NUMERICAL SIMULATION OF INTERACTION OF DETONATION WAVE WITH HOMOGENEOUS  

E-Print Network (OSTI)

DIRECT NUMERICAL SIMULATION OF INTERACTION OF DETONATION WAVE WITH HOMOGENEOUS ISOTROPIC TURBULENCE SIMULATION OF INTERACTION OF DETONATION WAVE WITH HOMOGENEOUS ISOTROPIC TURBULENCE HARI NARAYANAN NAGARAJAN The propagation of a shock or detonation wave through a reactive mixture has been the subject of research for over

Texas at Arlington, University of

85

Numerical simulation of turbulent jet primary breakup in Diesel engines  

E-Print Network (OSTI)

Numerical simulation of turbulent jet primary breakup in Diesel engines Peng Zeng1 Marcus Herrmann and Aerospace Engineering Arizona State University "Micro-Macro Modelling and Simulation of Liquid-Vapour Flows" IRMA Strasbourg, 23.Jan.2008 #12;Introduction DNS of Primary Breakup in Diesel Injection Phase

Helluy, Philippe

86

Turbulent Erosion Of Persistent Cold-Air Pools: Numerical Simulations  

Science Journals Connector (OSTI)

High-resolution idealized numerical simulations are used to examine the turbulent removal of cold-air pools commonly observed in mountain valleys and basins. A control simulation with winds aloft increasing from 0.5 to 20 m s-1 over 20 h combined ...

Neil P. Lareau; John D. Horel

87

Numerical simulation of axisymmetric spheromak merging  

Science Journals Connector (OSTI)

Axisymmetric merging of spheromaks is studied extensively by means of a magnetohydrodynamic code. Merging simulations of identical and different spheromaks created by the Princeton slow induction method have revealed that (1) the total magnetic energy decreases rather quickly through reconnection while the magnetic helicity is reasonably conserved; (2) a hollow structure appears in the radial q profile when two different spheromaks merge while the q profile is doubled when the identical spheromaks merge; and (3) the postmerging toroidal flux becomes the sum of the premerging fluxes while the postmerging poloidal flux remains the same as the larger of premerging fluxes. It is also observed that kinetic energy once converted from the magnetic energy through reconnection is returned back to the agnetic energy near the end of the merging process this indicating a relaxation toward a lower?energy force?free equilibrium.

Tetsuya Sato; Y. Oda; S. Otsuka; K. Katayama; M. Katsurai

1983-01-01T23:59:59.000Z

88

Numerical simulations of welds of thick steel pieces of interest for the thermonuclear fusion ITER machine  

E-Print Network (OSTI)

Numerical simulations of welds of thick steel pieces of interest for the thermonuclear fusion ITER machine

Carmignani, B

2005-01-01T23:59:59.000Z

89

Detonation shock dynamics and comparisons with direct numerical simulation  

E-Print Network (OSTI)

Detonation shock dynamics and comparisons with direct numerical simulation Tariq D. Aslam # , and D­ nation and detonation shock dynamics (DSD) is made. The theory of DSD defines the motion of the detonation shock in terms of intrinsic geometry of the shock surface, in particular for condensed phase ex

Aslam, Tariq

90

Detonation shock dynamics and comparisons with direct numerical simulation  

E-Print Network (OSTI)

Detonation shock dynamics and comparisons with direct numerical simulation Tariq D. Aslam , and D- nation and detonation shock dynamics (DSD) is made. The theory of DSD defines the motion of the detonation shock in terms of intrinsic geometry of the shock surface, in particular for condensed phase ex

Aslam, Tariq

91

Numerical Simulation of Airmass Transformation over the Gulf of Mexico  

Science Journals Connector (OSTI)

A mesoscale numerical simulation (35 km) of a return-flow event over the Gulf of Mexico that occurred during the Gulf of Mexico Experiment (GUFMEX) is presented in order to examine the structure and the transformation of the polar air mass and to ...

Jocelyn Mailhot

1992-08-01T23:59:59.000Z

92

Numerical simulation of cooling gas injection using adaptive multiscale techniques  

E-Print Network (OSTI)

focus on reducing this effects. Only very recently, active cooling strategies have been developed alsoNumerical simulation of cooling gas injection using adaptive multiscale techniques Wolfgang Dahmen Mathematik, RWTH Aachen, Templergraben 55, 52056 Aachen Abstract The interaction of a jet of cooling gas

93

Numerical simulations of bedrock valley evolution by meandering rivers  

E-Print Network (OSTI)

of valley evolution pathways and the long-term stability of valley morphology under constant forcingNumerical simulations of bedrock valley evolution by meandering rivers with variable bank material Institute of Technology, Pasadena, California, USA Abstract Bedrock river valleys are fundamental components

94

NUMERICAL SIMULATION OF NATURAL GAS-SWIRL BURNER  

SciTech Connect

A numerical simulation of a turbulent natural gas jet diffusion flame at a Reynolds number of 9000 in a swirling air stream is presented. The numerical computations were carried out using the commercially available software package CFDRC. The instantaneous chemistry model was used as the reaction model. The thermal, composition, flow (velocity), as well as stream function fields for both the baseline and air-swirling flames were numerically simulated in the near-burner region, where most of the mixing and reactions occur. The results were useful to interpret the effects of swirl in enhancing the mixing rates in the combustion zone as well as in stabilizing the flame. The results showed the generation of two recirculating regimes induced by the swirling air stream, which account for such effects. The present investigation will be used as a benchmark study of swirl flow combustion analysis as a step in developing an enhanced swirl-cascade burner technology.

Ala Qubbaj

2005-03-01T23:59:59.000Z

95

Numerical and experimental investigations on vibration of simulated CANDU fuel bundles subjected to turbulent fluid flow.  

E-Print Network (OSTI)

??Vibration of simulated CANDU fuel bundles induced by coolant flow is investigated in this thesis through experiments and numerical simulations. Two simulated bundles and a (more)

Zhang, Xuan

2011-01-01T23:59:59.000Z

96

Numerical Simulations of Penetration and Overshoot in the Sun  

Science Journals Connector (OSTI)

We present numerical simulations of convective overshoot in a two-dimensional model of the solar equatorial plane. The model equations are solved in the anelastic approximation with enhanced thermal conductivity and viscosity for numerical stability. The simulated domain extends from 0.001 to 0.93 R?, spanning both convective and radiative regions. We show that convective penetration leads to a slightly extended, mildly subadiabatic temperature gradient beneath the convection zone, spanning approximately 0.05Hp, below which there is a rapid transition to a strongly subadiabatic region. A slightly higher temperature is maintained in the overshoot region by adiabatic heating from overshooting plumes. This enhanced temperature may partially account for the sound speed discrepancy between the standard solar model and helioseismology. Simulations conducted with tracer particles suggest that a fully mixed region exists down to at least 0.684 R?.

Tamara M. Rogers; Gary A. Glatzmaier; C. A. Jones

2006-01-01T23:59:59.000Z

97

22nd International Conference on Numerical Simulation of Plasmas (ICNSP) |  

NLE Websites -- All DOE Office Websites (Extended Search)

September 7, 2011, 9:00am to September 11, 2011, 5:00pm September 7, 2011, 9:00am to September 11, 2011, 5:00pm Conference Long Branch, NJ 22nd International Conference on Numerical Simulation of Plasmas (ICNSP) The purpose of this conference series, which started at the College of William and Mary in 1967 "to disseminate progress in the state-of-the-art of plasma simulation and to report specific applications of computer experiments to various areas of plasma physics," remains unchanged. On the other hand, the topics of the Conference, which has been expanded over the years, now include: Topics: Magnetic & Inertial Fusion Plasmas Space & Astrophysical Plasmas High Intensity Beams & Laser Plasma Interactions Low-temperature Plasmas Numerical Methods & High Performance Computing Scientific Visualization

98

Petascale Direct Numerical Simulations of Turbulent Channel Flow  

NLE Websites -- All DOE Office Websites (Extended Search)

Petascale Petascale Direct Numerical Simulations of Turbulent Channel Flow MyoungKyu Lee mk@ices.utexas.edu Department of Mechanical Engineering University of Texas at Austin ESP Meeting May, 2013 M.K. Lee (Univ of Texas, Austin) Petascale DNS of Turbulent Channel Flow ESP Meeting May, 2013 1 / 30 Contents Project Overview Performance Optimization Early Result Conclusion M.K. Lee (Univ of Texas, Austin) Petascale DNS of Turbulent Channel Flow ESP Meeting May, 2013 2 / 30 Project Overview Project Title ◮ Petascale Direct Numerical Simulations of Turbulent Channel Flow Goal ◮ Expanding our understand of wall-bounded turbulence Personnel ◮ P.I. : Robert Moser ◮ Primary Developer : M.K.Lee ◮ Software Engineering Support : Nicholas Malaya ◮ Catalyst : Ramesh Balakrishnan M.K. Lee (Univ of Texas, Austin) Petascale DNS of Turbulent Channel Flow ESP Meeting May, 2013 3 / 30 Turbulent

99

Numerical simulations of gravitational collapse in Einstein-aether theory  

E-Print Network (OSTI)

We study gravitational collapse of a spherically symmetric scalar field in Einstein-aether theory (general relativity coupled to a dynamical unit timelike vector field). The initial value formulation is developed, and numerical simulations are performed. The collapse produces regular, stationary black holes, as long as the aether coupling constants are not too large. For larger couplings a finite area singularity occurs. These results are shown to be consistent with the stationary solutions found previously.

David Garfinkle; Christopher Eling; Ted Jacobson

2007-07-01T23:59:59.000Z

100

Transient productivity index for numerical well test simulations  

SciTech Connect

The most difficult aspect of numerical simulation of well tests is the treatment of the Bottom Hole Flowing (BHF) Pressure. In full field simulations, this pressure is derived from the Well-block Pressure (WBP) using a numerical productivity index which accounts for the grid size and permeability, and for the well completion. This productivity index is calculated assuming a pseudo-steady state flow regime in the vicinity of the well and is therefore constant during the well production period. Such a pseudo-steady state assumption is no longer valid for the early time of a well test simulation as long as the pressure perturbation has not reached several grid-blocks around the well. This paper offers two different solutions to this problem: (1) The first one is based on the derivation of a Numerical Transient Productivity Index (NTPI) to be applied to Cartesian grids; (2) The second one is based on the use of a Corrected Transmissibility and Accumulation Term (CTAT) in the flow equation. The representation of the pressure behavior given by both solutions is far more accurate than the conventional one as shown by several validation examples which are presented in the following pages.

Blanc, G.; Ding, D.Y.; Ene, A. [Institut Francais du Petrole, Pau (France)] [and others

1997-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Numerical Simulation of Detonation Initiation by the Space-Time Conservation Element and Solution Element Method.  

E-Print Network (OSTI)

??This dissertation is focused on the numerical simulation of the detonation initiation process. The space-time Conservation Element and Solution Element (CESE) method, a novel numerical (more)

Wang, Bao

2010-01-01T23:59:59.000Z

102

Numerical Simulation of Flood Levels for Tropical Rivers  

Science Journals Connector (OSTI)

Flood forecasting is important for flood damage reduction. As a result of advances in the numerical methods and computer technologies, many mathematical models have been developed and used for hydraulic simulation of the flood. These simulations usually include the prediction of the flood width and depth along a watercourse. Results obtained from the application of hydraulic models will help engineers to take precautionary measures to minimize flood damage. Hydraulic models were used to simulate the flood can be classified into dynamic hydraulic models and static hydraulic models. The HEC-2 static hydraulic model was used to predict water surface profiles for Linggi river and Langat river in Malaysia. The model is based on the numerical solution of the one dimensional energy equation of the steady gradually varied flow using the iteration technique. Calibration and verification of the HEC-2 model were conducted using the recorded data for both rivers. After calibration, the model was applied to predict the water surface profiles for Q10, Q30, and Q100 along the watercourse of the Linggi river. The water surface profile for Q200 for Langat river was predicted. The predicted water surface profiles were found in agreement with the recorded water surface profiles. The value of the maximum computed absolute error in the predicted water surface profile was found to be 500 mm while the minimum absolute error was 20 mm only.

Thamer Ahmed Mohammed; Salim Said; Mohd Zohadie Bardaie; Shah Nor Basri

2011-01-01T23:59:59.000Z

103

Hydrodynamics of Hypersonic Jets: Experiments and Numerical Simulations  

E-Print Network (OSTI)

Stars form in regions of the galaxy that are denser and cooler than the mean interstellar medium. These regions are called Giant Molecular Clouds. At the beginning of their life, up to $10^5-10^6$ years, stars accrete matter from their rich surrounding environment and are origin of a peculiar phenomenon that is the jet emission. Jets from Young Stellar Objects (YSOs) are intensively studied by the astrophysical community by observations at different wavelengths, analytical and numerical modeling and laboratory experiments. Indications about the jet propagation and its resulting morphologies are here obtained by means of a combined study of hypersonic jets carried out both in the laboratory and by numerical simulations.

Belan, Marco; Tordella, Daniela; Massaglia, Silvano; Ferrari, Attilio; Mignone, Andrea; Bodenschatz, Eberhard

2011-01-01T23:59:59.000Z

104

False diffusion in numerical simulation of combustion processes in tangential-fired furnace  

Science Journals Connector (OSTI)

Numerical simulation serves as one of the most important tools for analyzing coal combustion in Tangentially Fired Furnaces (TFF) with NUMERICAL FALSE DIFFUSION as one key problem that degrades the simulation acc...

Xuchang Xu; Zhigang Wang; Yuqun Zhuo

2007-11-01T23:59:59.000Z

105

A Simulation and Decision Framework for Selection of Numerical Solvers in  

Science Journals Connector (OSTI)

Selecting the right numerical solver or the most appropriate numerical package for a particular simulation problem it is increasingly difficult for users without an extensive mathematical background and deeper knowledge in numerical analysis. In this ...

Peter Bunus

2006-04-01T23:59:59.000Z

106

Numerical simulation of contaminant flow in a wool scour  

Science Journals Connector (OSTI)

Wool scouring is the process of washing dirty wool after shearing. Our model numerically simulates contaminant movement in a wool scour bowl using the advectiondispersion equation. This is the first wool scour model to give time-dependent results and to model the transport of contaminants within a single scour bowl. Our aim is to gain a better understanding of the operating parameters that will produce efficient scouring. Investigating the effects of varying the parameters reveals simple, interesting relationships that give insight into the dynamics of a scour bowl.

J.F. Caunce; S.I. Barry; G.N. Mercer; T.R. Marchant

2007-01-01T23:59:59.000Z

107

Numerical simulation of carbon arc discharge for nanoparticle synthesis  

SciTech Connect

Arc discharge with catalyst-filled carbon anode in helium background was used for the synthesis of carbon nanoparticles. In this paper, we present the results of numerical simulation of carbon arc discharges with arc current varying from 10 A to 100 A in a background gas pressure of 68 kPa. Anode sublimation rate and current voltage characteristics are compared with experiments. Distribution of temperature and species density, which is important for the estimation of the growth of nanoparticles, is obtained. The probable location of nanoparticle growth region is identified based on the temperature range for the formation of catalyst clusters.

Kundrapu, M.; Keidar, M. [Department of Mechanical and Aerospace Engineering, George Washington University, Washington, DC 20052 (United States)

2012-07-15T23:59:59.000Z

108

Numerical simulation of the Tayler instability in liquid metals  

E-Print Network (OSTI)

The electrical current through an incompressible, viscous and resistive liquid conductor produces an azimuthal magnetic field that becomes unstable when the corresponding Hartmann number exceeds a critical value in the order of 20. This Tayler instability, which is not only discussed as a key ingredient of a non-linear stellar dynamo model (Tayler-Spruit dynamo), but also as a limiting factor for the maximum size of large liquid metal batteries, was recently observed experimentally in a column of a liquid metal (Seilmayer et al., Phys. Rev. Lett. 108, 244501, 2012}. On the basis of an integro-differential equation approach, we have developed a fully three-dimensional numerical code, and have utilized it for the simulation of the Tayler instability at typical viscosities and resistivities of liquid metals. The resulting growth rates are in good agreement with the experimental data. We illustrate the capabilities of the code for the detailed simulation of liquid metal battery problems in realistic geometries.

Weber, Norbert; Stefani, Frank; Weier, Tom; Wondrak, Thomas

2012-01-01T23:59:59.000Z

109

Numerical simulation of turbulence interaction noise applied to a serrated airfoil  

E-Print Network (OSTI)

Numerical simulation of turbulence interaction noise applied to a serrated airfoil Vincent CLAIR, Gabriel Reboul, Thomas Le Garrec. Numerical simulation of turbulence interaction noise applied, des laboratoires publics ou priv´es. #12;Numerical simulation of turbulence interaction noise applied

110

VNIIEF VNIIEF Methods of Numerical Simulation for Multi-  

National Nuclear Security Administration (NNSA)

32 32 VNIIEF VNIIEF Methods of Numerical Simulation for Multi- Methods of Numerical Simulation for Multi- Dimensional Gas Dynamic Flows Dimensional Gas Dynamic Flows Spir Spiri idonov donov V.F V.F., ., Bakhrakh Bakhrakh S.M., S.M., Velichko Velichko S.V., S.V., Delov Delov V.I., V.I., Yanilkin Yu.V Yanilkin Yu.V., ., Sokolov Sokolov S.S., S.S., Butnev Butnev O.I, O.I, Stenin Stenin A.M., A.M., Zmushko Zmushko V.V., V.V., Voronin Voronin B.L., B.L., Bykov Bykov A.N. A.N. RFCN-VNIIEF, 607190, RFCN-VNIIEF, 607190, Sarov Sarov, , Nizhni Nizhni Novgorod region Novgorod region Joint Russian-American Five-Laboratory Conference on Computation Joint Russian-American Five-Laboratory Conference on Computation Mathematics|Physics Mathematics|Physics 19-23 June 2005, 19-23 June 2005, Crowne

111

Kinetic theory and numerical simulations of two-species coagulation  

E-Print Network (OSTI)

In this work we study the stochastic process of two-species coagulation. This process consists in the aggregation dynamics taking place in a ring. Particles and clusters of particles are set in this ring and they can move either clockwise or counterclockwise. They have a probability to aggregate forming larger clusters when they collide with another particle or cluster. We study the stochastic process both analytically and numerically. Analytically, we derive a kinetic theory which approximately describes the process dynamics. One of our strongest assumptions in this respect is the so called well-stirred limit, that allows neglecting the appearance of spatial coordinates in the theory, so this becomes effectively reduced to a zeroth dimensional model. We determine the long time behavior of such a model, making emphasis in one special case in which it displays self-similar solutions. In particular these calculations answer the question of how the system gets ordered, with all particles and clusters moving in the same direction, in the long time. We compare our analytical results with direct numerical simulations of the stochastic process and both corroborate its predictions and check its limitations. In particular, we numerically confirm the ordering dynamics predicted by the kinetic theory and explore properties of the realizations of the stochastic process which are not accessible to our theoretical approach.

Carlos Escudero; Fabricio Macia; Raul Toral; Juan J. L. Velazquez

2014-04-19T23:59:59.000Z

112

Numerical Relativity in Spherical Polar Coordinates: Off-center Simulations  

E-Print Network (OSTI)

We have recently presented a new approach for numerical relativity simulations in spherical polar coordinates, both for vacuum and for relativistic hydrodynamics. Our approach is based on a reference-metric formulation of the BSSN equations, a factoring of all tensor components, as well as a partially implicit Runge-Kutta method, and does not rely on a regularization of the equations, nor does it make any assumptions about the symmetry across the origin. In order to demonstrate this feature we present here several off-centered simulations, including simulations of single black holes and neutron stars whose center is placed away from the origin of the coordinate system, as well as the asymmetric head-on collision of two black holes. We also revisit our implementation of relativistic hydrodynamics and demonstrate that a reference-metric formulation of hydrodynamics together with a factoring of all tensor components avoids problems related to the coordinate singularities at the origin and on the axes. As a particularly demanding test we present results for a shock wave propagating through the origin of the spherical polar coordinate system.

Thomas W. Baumgarte; Pedro J. Montero; Ewald Mller

2015-01-21T23:59:59.000Z

113

Numerical Relativity in Spherical Polar Coordinates: Off-center Simulations  

E-Print Network (OSTI)

We have recently presented a new approach for numerical relativity simulations in spherical polar coordinates, both for vacuum and for relativistic hydrodynamics. Our approach is based on a reference-metric formulation of the BSSN equations, a factoring of all tensor components, as well as a partially implicit Runge-Kutta method, and does not rely on a regularization of the equations, nor does it make any assumptions about the symmetry across the origin. In order to demonstrate this feature we present here several off-centered simulations, including simulations of single black holes and neutron stars whose center is placed away from the origin of the coordinate system, as well as the asymmetric head-on collision of two black holes. We also revisit our implementation of relativistic hydrodynamics and demonstrate that a reference-metric formulation of hydrodynamics together with a factoring of all tensor components avoids problems related to the coordinate singularities at the origin and on the axes. As a parti...

Baumgarte, Thomas W; Mller, Ewald

2015-01-01T23:59:59.000Z

114

Numerical simulation of the impeller tip clearance effect on centrifugal compressor performance  

E-Print Network (OSTI)

This thesis presents the numerical simulation of flow in centrifugal compressors. A three-dimensional Navier-Stokes solver was employed to simulate flow through two centrifugal compressors. The first compressor simulated was the NASA low speed...

Hoenninger, Corbett Reed

2012-06-07T23:59:59.000Z

115

Accurate Numerical Simulations Of Chemical Phenomena Involved in Energy  

NLE Websites -- All DOE Office Websites (Extended Search)

Visualization of the spin density from the excess electron cluster. Robert Visualization of the spin density from the excess electron cluster. Robert Harrison Accurate Numerical Simulations Of Chemical Phenomena Involved in Energy Production and Storage with MADNESS and MPQC PI Name: Robert Harrison PI Email: harrisonrj@ornl.gov Institution: ORNL Allocation Program: ESP Allocation Hours at ALCF: 150 Million Year: 2010 to 2013 Research Domain: Chemistry Researchers propose to focus on the problems of catalysis and heavy element chemistry for fuel reprocessing-both of which are of immediate interest to the Department of Energy (DOE), are representative of a very broad class of problems in chemistry, and demand the enormous computational resources anticipated from the next generation of leadership computing facilities. Also common to both is the need for accurate electronic structure

116

Numerical Simulation and Optimazation of Small Scale LNG Plant  

Science Journals Connector (OSTI)

The LNG20 is a small?scale natural gas liquefier. Its capacity is 20 cube meters LNG per day. This liquefier could be used for the pipeline gas coalbed gas oil field gas liquefaction and peakshaving plant for town gas gate station and natural gas power plant. Two processing cycles are applied to LNG20 nitrogen expander cycle and mixed refrigerant cycle. In this report two feed gases are the target sources; one is the pipeline gas in West?to?east pipeline gas in a gate station in Zhejiang province and coalbed gas in Northeast China. The numerical simulation and optimization for the LNG20 were carried out to obtain the design parameters.

H. Y. Li; L. X. Jia; Q. H. Fan; Q. S. Yin

2006-01-01T23:59:59.000Z

117

A Flux-Limited Numerical Method for the MHD Equations to Simulate Propulsive Plasma Flows  

E-Print Network (OSTI)

to be effective tools in plasma propulsion research, a higher order accu- rate solver that captures MHD shocks approach, numerical simulations are valuable tools in plasma thruster research. More- over, simulations can Simula- tions The importance of numerical simulation in advancing plasma thruster research was realized

Choueiri, Edgar

118

American Institute of Aeronautics and Astronautics Numerical Simulation of Detonation Processes in a  

E-Print Network (OSTI)

American Institute of Aeronautics and Astronautics 1 Numerical Simulation of Detonation Processes The detonation processes occurring in a combustion chamber with variable cross-sections are numerically simulated-species, two-step global reaction mechanism is used. Two detonation cases are simulated, corresponding

Texas at Arlington, University of

119

CFD Numerical Simulation of Vortex-Induced Vibration of a Stay Cable under a Wind Profile  

Science Journals Connector (OSTI)

VIV (Vortex-induced vibration) of a stay cable subjected to a wind profile is numerically simulated through combining CFD ... numerical model. Under a profile of mean wind speed, unsteady aerodynamic lift coeffic...

Wenli Chen; Hui Li

2009-01-01T23:59:59.000Z

120

Numerical simulation of wind resonance of a circular profile by means of the vortex element method  

Science Journals Connector (OSTI)

The problem regarding the numerical simulation of a circular profile motion in a ... element method is used. The phenomenon of wind resonance has been examined. The investigation has...

I. K. Marchevskii; O. I. Ivanov

2009-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

DIPOLE COLLAPSE AND DYNAMO WAVES IN GLOBAL DIRECT NUMERICAL SIMULATIONS  

SciTech Connect

Magnetic fields of low-mass stars and planets are thought to originate from self-excited dynamo action in their convective interiors. Observations reveal a variety of field topologies ranging from large-scale, axial dipoles to more structured magnetic fields. In this article, we investigate more than 70 three-dimensional, self-consistent dynamo models in the Boussinesq approximation obtained by direct numerical simulations. The control parameters, the aspect ratio, and the mechanical boundary conditions have been varied to build up this sample of models. Both strongly dipolar and multipolar models have been obtained. We show that these dynamo regimes in general can be distinguished by the ratio of a typical convective length scale to the Rossby radius. Models with a predominantly dipolar magnetic field were obtained, if the convective length scale is at least an order of magnitude larger than the Rossby radius. Moreover, we highlight the role of the strong shear associated with the geostrophic zonal flow for models with stress-free boundary conditions. In this case the above transition disappears and is replaced by a region of bistability for which dipolar and multipolar dynamos coexist. We interpret our results in terms of dynamo eigenmodes using the so-called test-field method. We can thus show that models in the dipolar regime are characterized by an isolated 'single mode'. Competing overtones become significant as the boundary to multipolar dynamos is approached. We discuss how these findings relate to previous models and to observations.

Schrinner, Martin; Dormy, Emmanuel [MAG (ENS/IPGP), LRA, Ecole Normale Superieure, 24 Rue Lhomond, 75252 Paris Cedex 05 (France); Petitdemange, Ludovic, E-mail: martin@schrinner.eu [Previously at Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg, Germany. (Germany)

2012-06-20T23:59:59.000Z

122

Numerical simulation of laminar flow in a curved duct  

SciTech Connect

This paper describes numerical simulations that were performed to study laminar flow through a square duct with a 900 bend. The purpose of this work was two fold. First, an improved understanding was desired of the flow physics involved in the generation of secondary vortical flows in three-dimensions. Second, adaptive gridding techniques for structured grids in three- dimensions were investigated for the purpose of determining their utility in low Reynolds number, incompressible flows. It was also of interest to validate the commercial computer code CFD-ACE. Velocity predictions for both non-adaptive and adaptive grids are compared with experimental data. Flow visualization was used to examine the characteristics of the flow though the curved duct in order to better understand the viscous flow physics of this problem. Generally, moderate agreement with the experimental data was found but shortcomings in the experiment were demonstrated. The adaptive grids did not produce the same level of accuracy as the non-adaptive grid with a factor of four more grid points.

Lopez, A.R.; Oberkampf, W.L.

1995-01-01T23:59:59.000Z

123

Numerical Simulation of Transient Fields F. Messerer, C. Trinitis*, W. Boeck, G. Schoffner  

E-Print Network (OSTI)

of HV equipment. Therefore it is useful to have a tool to simulate transient fields with numerical manufactured by SIEMENS for Gas Insulated Substation (GIS) used in 145kV systems. The simulation model (figure

Stamatakis, Alexandros

124

Numerical Simulations of Bow Echo Formation Following a Squall LineSupercell Merger  

Science Journals Connector (OSTI)

Output from idealized numerical simulations is used to investigate the storm-scale processes responsible for squall-line evolution following a merger with an isolated supercell. A simulation including a squall linesupercell merger is compared to ...

Adam J. French; Matthew D. Parker

2014-12-01T23:59:59.000Z

125

Spiral Rainbands in a Numerical Simulation of Hurricane Bill (2009). Part II: Propagation of Inner Rainbands  

Science Journals Connector (OSTI)

This is the second part of a study that examines spiral rainbands in a numerical simulation of Hurricane Bill (2009). This paper evaluates whether the propagation of inner rainbands in the Hurricane Bill simulation is consistent with previously ...

Yumin Moon; David S. Nolan

126

t -software package for numerical simulations of radioactive contaminant transport in groundwater  

E-Print Network (OSTI)

r3 t - software package for numerical simulations of radioactive contaminant transport equations that arise from the modelling of radioactive contaminant transport in porous media. It can solve, see [6]) can help to numerically simulate the spreading of radioactive contaminants in flowing ground

Frolkovic, Peter

127

Impact of airborne Doppler wind lidar profiles on numerical simulations of a tropical cyclone  

E-Print Network (OSTI)

Click Here for Full Article Impact of airborne Doppler wind lidar profiles on numerical simulations Regional Campaign (TPARC) field experiment in 2008, an airborne Doppler wind lidar (DWL) was onboard the U measurements on the numerical simulation of Typhoon Nuri (2008) in its formation phase. With an advanced

Pu, Zhaoxia

128

CALTECH ASCI TECHNICAL REPORT 135 Analysis of Numerical Simulations of Detonation Diffraction  

E-Print Network (OSTI)

CALTECH ASCI TECHNICAL REPORT 135 Analysis of Numerical Simulations of Detonation Diffraction M. Arienti and J.E.Shepherd #12;Analysis of Numerical Simulations of Detonation Diffraction Marco Arienti Abstract We investigate the problem of a self-sustaining detonation wave diffracting from a tube

Barr, Al

129

Numerical simulation of the heat transfer in amorphous silicon nitride membrane-based microcalorimeters  

E-Print Network (OSTI)

Numerical simulation of the heat transfer in amorphous silicon nitride membrane July 2003 Numerical simulations of the two-dimensional 2D heat flow in a membrane-based microcalorimeter have been performed. The steady-state isotherms and time-dependent heat flow have been calculated

Hellman, Frances

130

NUMERICAL SIMULATION OF POOL BOILING FOR STEADY STATE AND TRANSIENT HEATING  

E-Print Network (OSTI)

1 NUMERICAL SIMULATION OF POOL BOILING FOR STEADY STATE AND TRANSIENT HEATING Ying He, Masahiro role in nucleate and transition boiling heat transfer at high heat flux. Many experiments have been in the numerical simulation of boiling heat transfer. In this study, based on the macrolayer evaporation model

Maruyama, Shigeo

131

Stochastic Microstructure Reconstruction and Direct Numerical Simulation of the PEFC Catalyst Layer  

E-Print Network (OSTI)

Stochastic Microstructure Reconstruction and Direct Numerical Simulation of the PEFC Catalyst Layer, USA A direct numerical simulation DNS model of species and charge transport in the cathode catalyst of the catalyst layer has been reconstructed based on a stochastic technique using the low-order statistical

132

Direct Numerical Simulation of a Hypersonic Turbulent Boundary Layer on a Large Domain  

E-Print Network (OSTI)

Direct Numerical Simulation of a Hypersonic Turbulent Boundary Layer on a Large Domain Stephan Priebe , M. Pino Mart´in The direct numerical simulation (DNS) of a spatially-developing hypersonic There are few studies of hypersonic flows at Mach number greater than 5 and few involve the measurement of mean

Martín, Pino

133

Adaptive higher order numerical simulation of heat and mass transfer in fluidized beds  

E-Print Network (OSTI)

Adaptive higher order numerical simulation of heat and mass transfer in fluidized beds Ch. Nagaiah1 adaptive numerical results of heat and mass transfer in fluidized beds using higher order time stepping injection. The numerical results are tested with different time stepping methods for different spatial grid

Magdeburg, Universität

134

Numerical simulations of supercell interactions with thermal boundaries  

E-Print Network (OSTI)

simulation. Backward trajectories computed for the (a, b) control simulation starting at 115 min. and (c, d) -6 K simulation starting at 150 min. . Average trajectory for parcels entering the updraft from the northeast for the control simulation starting... information. The most exhaustive observational study of outflow boundaries is discussed in Maddox et al. (1980). This work specifically focused on the interaction of tornadic storms with outflow boundaries. The authors sought to explain the observations...

Kay, Michael Paul

2012-06-07T23:59:59.000Z

135

Numerical Simulation of Cold Pressing of Armstrong CP-Ti Powders  

SciTech Connect

Numerical simulation results for the cold pressing of Armstrong CP-Ti Powders are presented. The computational model was implemented in the commercial finite element program ABAQUSTM. Several simulation cases were conducted for cylindrical samples with different friction coefficients and different compaction pressures, under both single-action and dual-action uniaxial pressing. Numerical simulation results for the density distribution are compared against experimental data in order to validate the computational model.

Sabau, Adrian S [ORNL] [ORNL; Gorti, Sarma B [ORNL] [ORNL; Peter, William H [ORNL] [ORNL; Chen, Wei [ORNL] [ORNL; Yamamoto, Yukinori [ORNL] [ORNL

2012-01-01T23:59:59.000Z

136

Investigating dynamic underground coal fires by means of numerical simulation  

Science Journals Connector (OSTI)

......available within the combustion centre. Combustion will only proceed whenever...controls the overall combustion rate. For numerical...transport-only and a chemistry-only part. Common...rate of underground coal fires by oxygen transport......

S. Wessling; W. Kessels; M. Schmidt; U. Krause

2008-01-01T23:59:59.000Z

137

Numerical Simulations of Water Wave Propagation and Flooding  

Science Journals Connector (OSTI)

In this paper we present main points in the process of application of numerical schemes for hyperbolic balance laws to water wave propagation and flooding. The appropriate mathematical models are the one ... two-...

Luka Sopta; Nelida ?rnjari?-ic

2005-01-01T23:59:59.000Z

138

The Interaction of Numerically Simulated Supercells Initiated along Lines  

Science Journals Connector (OSTI)

Supercells in the southern plains are often localized, forming as cells along a convective line, even though the environment may support supercell formation over a much broader, mesoscale region. A set of numerical experiments is devised in which ...

Howard B. Bluestein; Morris L. Weisman

2000-09-01T23:59:59.000Z

139

Tracer method in numerical simulation of combustion processes  

Science Journals Connector (OSTI)

Fuel-rich laminar flat hydrogen-methane-air flames are studied numerically using the tracer method. It is found that, in the near-limit mixture, hydrogen has an advantage in the oxidation by oxygen. As the sto...

V. A. Bunev; A. V. Baklanov; I. G. Namyatov

2007-11-01T23:59:59.000Z

140

Direct Numerical Simulations in Engine-like Geometries | Argonne...  

NLE Websites -- All DOE Office Websites (Extended Search)

Location: Argonne National Laboratory Speaker(s): Martin Schmitt Speaker(s) Title: ETH Zurich Engine simulations based on RANS and LES depend on the mesh resolution and...

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

VOL. 19 NO. 1 ACTA METEOROLOGICA SINICA 2005 Numerical Simulation of Wind and Temperature Fields  

E-Print Network (OSTI)

VOL. 19 NO. 1 ACTA METEOROLOGICA SINICA 2005 Numerical Simulation of Wind and Temperature Fields of fuel consumed in the Xi'an industrial area. Tong and Sang (2002) simulated the wind, temperature that the wind field is affected by the topography and urban heat island. Yang et al. (2003) simulated the winter

Thompson, Anne

142

NUMERICAL SIMULATIONS OF HEAT TRANSFER AND FLUID FLOW PROBLEMS USING AN  

E-Print Network (OSTI)

NUMERICAL SIMULATIONS OF HEAT TRANSFER AND FLUID FLOW PROBLEMS USING AN IMMERSED-BOUNDARY FINITE of the immersed boundary technique for simulating fluid flow and heat transfer problems over or inside complex. Several phenomenologically different fluid flow and heat transfer problems are simulated using

Pacheco, Jose Rafael

143

Numerical  

NLE Websites -- All DOE Office Websites (Extended Search)

of the mean flow, in which turbulence generated currents are investigated in subcritical flows. II. NUMERICAL MODEL The numerical model used in this paper solves the MHD...

144

Evaluation of a distributed numerical simulation optimization approach applied to aquifer remediation  

Science Journals Connector (OSTI)

In this paper we evaluate a distributed approach which uses numerical simulation and optimization techniques to automatically find remediation solutions to a hypothetical contaminated aquifer. The repeated execution of the numerical simulation model of the aquifer through the optimization cycles tends to be computationally expensive. To overcome this drawback, the numerical simulations are executed in parallel using a network of heterogeneous workstations. Performance metrics for heterogeneous environments are not trivial; a new way of calculating speedup and efficiency for Bag-of-Tasks (BoT) applications is proposed. The performance of the parallel approach is evaluated.

Patrcia A.P. Costa; Eduardo L.M. Garcia; Bruno Schulze; Helio J.C. Barbosa

2010-01-01T23:59:59.000Z

145

Numerical Simulation in Applied Geophysics. From the Mesoscale to ...  

E-Print Network (OSTI)

Instead of solving the global problem associated with the above model, we obtained the solution using a parallel FE ... Black-Oil simulator. .... used in hydrocarbon exploration geophysics, mining and reservoir characterization and production.

146

MULTIDIMENSIONAL NUMERICAL SIMULATION OF FLUID FLOW IN FRACTURED POROUS MEDIA  

E-Print Network (OSTI)

and fluid flow in the hydraulic fracturing process." Ph.D.depth by means of hydraulic fracturing." in Rock Mechanics:Fig. 13. Simulation of hydraulic fracturing: field data on

Narasimhan, T.N.

2014-01-01T23:59:59.000Z

147

Discrete Propagation in Numerically Simulated Nocturnal Squall Lines  

Science Journals Connector (OSTI)

Simulations of a typical midlatitude squall line were used to investigate a mechanism for discrete propagation, defined as convective initiation ahead of an existing squall line leading to a faster propagation speed for the storm complex. Radar ...

Robert G. Fovell; Gretchen L. Mullendore; Seung-Hee Kim

2006-12-01T23:59:59.000Z

148

Investigating dynamic underground coal fires by means of numerical simulation  

Science Journals Connector (OSTI)

......is the key to successful prediction of various combustion processes (Hjertager 1986). Ten years ago, limited computer...Blasi C.D. ,1993. Modeling and simulation of combustion processes of charring and non-charring solid fuels, Prog......

S. Wessling; W. Kessels; M. Schmidt; U. Krause

2008-01-01T23:59:59.000Z

149

Numerical simulation of fluid flow in porous/fractured media  

SciTech Connect

Theoretical models of fluid flow in porous/fractured media can help in the design of in situ fossil energy and mineral extraction technologies. Because of the complexity of these processes, numerical solutions are usually required. Sample calculations illustrate the capabilities of present day computer models.

Travis B.J.; Cook, T.L.

1981-01-01T23:59:59.000Z

150

Threedimensional numerical simulation of the temperature, potential and concentration  

E-Print Network (OSTI)

with the mathematical modelling and numerical simu­ lation of natural gas­fed solid oxide cells (Solid Oxide Fuel Cell, SOFC). The physics of fuel cell operation and the simplifying assumptions which are taken into account.1 The mathematical model A 3D model of a cell is obtained by writing the conservation laws in the solid parts

Herbin, Raphaèle

151

Structure and Evolution of Numerically Simulated Squall Lines  

Science Journals Connector (OSTI)

Using a three-dimensional numerical cloud model, we investigate the effects of vertical wind shear on squall-line structure and evolution over a wide range of shear magnitudes, depths, and orientations relative to the line. We find that the ...

Morris L. Weisman; Joseph B. Klemp; Richard Rotunno

1988-07-01T23:59:59.000Z

152

Numeric simulation of thyristor power converters taking into consideration the firing-circuits and the closed-loop control  

E-Print Network (OSTI)

Numeric simulation of thyristor power converters taking into consideration the firing-circuits and the closed-loop control

Bordry, Frederick; Proudlock, Paul

1988-01-01T23:59:59.000Z

153

Wind Tunnel Experiments and Numerical Simulation of Snow Drifting around an Avalanche Protecting Dam  

Science Journals Connector (OSTI)

To learn about wind flow and snow drifting around avalanche dams, ... experiments were done in the Jules Verne Climatic Wind Tunnel. The paper reports the results from numerical wind flow simulations that were do...

Skuli Thordarson

2002-12-01T23:59:59.000Z

154

Numerical Simulation of Wind Currents and Propagation of Impurities in the Balaklava Bay  

Science Journals Connector (OSTI)

We present the results of numerical experiments aimed at the simulation of the circulation of waters and transport ... of impurities in the Balaklava Bay for typical wind conditions established on the basis of th...

V. V. Fomin; L. N. Repetin

2005-07-01T23:59:59.000Z

155

Numerical Simulation of the December 26, 2004 Indian Ocean Tsunami using a Boussinesq model  

E-Print Network (OSTI)

Numerical Simulation of the December 26, 2004 Indian Ocean Tsunami using a Boussinesq model Philip for the December 26, 2004 Indian Ocean tsunami. Calculations are based on Boussinesq model FUNWAVE and are carried

Kirby, James T.

156

Neutrino Factory / Muon Collider Target Meeting Numerical Simulations for Jet-Proton  

E-Print Network (OSTI)

breakup observed in simulations Mercury is able to sustain very large tension Jet oscillates after on the surface of a hydrofoil Pressure contour in mercury target. #12;13 The Bubble Insertion Model Numerical

McDonald, Kirk

157

Numerical simulations of ion transport membrane oxy-fuel reactors for CO? capture applications  

E-Print Network (OSTI)

Numerical simulations were performed to investigate the key features of oxygen permeation and hydrocarbon conversion in ion transport membrane (ITM) reactors. ITM reactors have been suggested as a novel technology to enable ...

Hong, Jongsup

2013-01-01T23:59:59.000Z

158

Numerical simulation of the interaction of atmospheric pressure plasma discharges with dielectric surfaces.  

E-Print Network (OSTI)

??In this Ph.D. thesis, we have carried out 2D numerical simulations to study the influence of dielectric surfaces on the propagation dynamics of plasma discharges (more)

Pechereau, Franois

2013-01-01T23:59:59.000Z

159

Numerical simulation of three-dimensional combined convective radiative heat transfer in rectangular channels  

E-Print Network (OSTI)

This dissertation presents a numerical simulation of three-dimensional flow and heat transfer in a channel with a backward-facing step. Flow was considered to be steady, incompressible, and laminar. The flow medium was treated to be radiatively...

Ko, Min Seok

2009-05-15T23:59:59.000Z

160

Simulating Flood Propagation in Urban Areas using a Two-Dimensional Numerical Model.  

E-Print Network (OSTI)

??A two-dimensional numerical model (RiverFLO-2D) has been enhanced to simulate flooding of urban areas by developing an innovative wet and dry surface algorithm, accounting for (more)

Gonzalez-Ramirez, Noemi

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Numerical simulation of the Mindanao Eddy and Tropical Currents of Pacific Ocean  

Science Journals Connector (OSTI)

Results of numerical simulation of currents in the western North Tropical Pacific Ocean by using a barotropic primitive equation model ... strength-circulation systems such as the North Equatorial Current, the Mi...

Li Rongfeng; Zeng Qingcun; Ji Zhongzhen

1992-09-01T23:59:59.000Z

162

Numerical Simulation/Analysis and Computer Aided Engineering for Virtual Protyping of Heavy Ground Vehicle  

E-Print Network (OSTI)

Heavy Ground Vehicles. The numerical simulation technology capabilities are fully explored to specifically tackle the kinematics, dynamics, statics, and structural problems, some with the added realism of today's 3D high fidelity graphical environment...

Abd. Rahim, Mohd. Razi

2010-08-26T23:59:59.000Z

163

Boundary coupled dual-equation numerical simulation on mass transfer in the process of laser cladding  

Science Journals Connector (OSTI)

The coupled numerical simulation on fluid flow, heat transfer, and mass transfer in the process of laser cladding is undertaken on the basis of the continuum model. In the...

Huang, Yanlu; Yang, Yongqiang; Wei, Guoqiang; Shi, Wenqing; Li, Yibin

2008-01-01T23:59:59.000Z

164

Numerical simulation of the response of sandy soils treated with pre-fabricated vertical drains  

E-Print Network (OSTI)

This research is part of the ongoing effort of the Seismic Risk Mitigation for Port Systems Grand Challenge. It addresses the problem of numerically simulating the response of sandy soils treated with earthquake drains, ...

Vytiniotis, Antonios

2009-01-01T23:59:59.000Z

165

Numerical simulation of large amplitude liquid sloshing in a rigid rectangular tank  

E-Print Network (OSTI)

NUMERICAL SIMULATION OF LARGE AMPLITUDE LIQUID SLOSHING IN A RIGID RECTANGULAR TANK A Thesis by THOMAS JACKSON BRIDGES Submitted to the Graduate College of Texas A8M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIE'ICE December 1981 Major Subject: Ocean Engineering NUMERICAL SIMULATION OF LARGE AMPLITUDE LIQUID SLOSHING IN A RIGID RECTANGULAR TANK A Thesis by THOMAS JACKSON BRIDGES Approved as to sty1e and content by: (Chairman of Commit ee...

Bridges, Thomas J.

1981-01-01T23:59:59.000Z

166

Numerical Simulation of Displacement Mechanisms for Enhancing Heavy Oil Recovery during Alkaline Flooding  

Science Journals Connector (OSTI)

In this paper, a simulation technique has been developed and successfully applied to numerically simulate the experimentally determined displacement mechanisms governing alkaline flooding for enhancing oil recovery in heavy oil reservoirs. ... (8-13) The existing simulation techniques used for alkaline flooding in the conventional oil reservoirs result in significant discrepancy between the experimental and simulated pressure drop for alkaline flooding in heavy oil reservoirs. ... Both the scientific findings and the newly developed simulation technique will facilitate simulating and designing field-scale alkaline flooding for heavy oil reservoirs. ...

Mohamed Arhuoma; Daoyong Yang; Mingzhe Dong; Heng Li; Raphael Idem

2009-10-15T23:59:59.000Z

167

Context DDFV Scheme Numerical analysis ECG Simulation 2D/3D DDFV scheme for anisotropic-heterogeneous  

E-Print Network (OSTI)

Context DDFV Scheme Numerical analysis ECG Simulation 2D/3D DDFV scheme for anisotropic Numerical analysis ECG Simulation Authors : Laboratoire de math´ematiques Jean Leray, Universit´e de Nantes Pays de l'Adour : · Charles Pierre #12;Context DDFV Scheme Numerical analysis ECG Simulation Outline

Pierre, Charles

168

Numerical simulation of scour process around bridge piers in cohesive soil  

E-Print Network (OSTI)

This thesis is concerned with numerical simulation of scour process in cohesive soil around cylindrical bridge piers. The numerical method is a multi-block chimera Reynolds-Averaged Navier-Stokes (RANS) method in a general body-fitted curvilinear...

Wei, Gengsheng

2012-06-07T23:59:59.000Z

169

COMPARISON BETWEEN EXPERIMENTAL TESTS AND NUMERICAL SIMULATIONS CARRIED OUT ON A TENSEGRITY MINI GRID  

E-Print Network (OSTI)

. For our purposes, one eighth of this grid was used, which we refer to as a mini grid. 2. NUMERICAL STUDY OF THE MINI GRID hal-00359400,version1-16Feb2009 #12;Mini grid This is a double layer plane grid of cablesCOMPARISON BETWEEN EXPERIMENTAL TESTS AND NUMERICAL SIMULATIONS CARRIED OUT ON A TENSEGRITY MINI

Paris-Sud XI, Université de

170

Numerical simulation of turbulence interaction noise applied to a serrated airfoil  

E-Print Network (OSTI)

Numerical simulation of turbulence interaction noise applied to a serrated airfoil V. Clair, C, but they are limited by the flat-plate assumptions. The development of numerical methods allowing more complex code solving the nonlinear Euler equations. The upstream turbulence is synthesized from a stochastic

Boyer, Edmond

171

Effects of Shear Rate on Propagation of Blood Clotting Determined Using Microfluidics and Numerical Simulations  

E-Print Network (OSTI)

Effects of Shear Rate on Propagation of Blood Clotting Determined Using Microfluidics and Numerical-ismagilov@uchicago.edu Abstract: This paper describes microfluidic experiments with human blood plasma and numerical simulations removed. In addition, these results demonstrate the utility of simplified mechanisms and microfluidics

Ismagilov, Rustem F.

172

Numerical Simulation in Applied Geophysics. From the Mesoscale to ...  

E-Print Network (OSTI)

Instituto del Gas y del Petroleo, Facultad de Ingenier?a UBA. ,. Facultad de ... hydrocarbon exploration geophysics, mining and reservoir characterization and production. Local variations in the fluid ... physical process of wave propagation can be inspected during the experiment. ..... Black-Oil simulator. CO2 saturation...

2013-07-05T23:59:59.000Z

173

Numerical Simulations of Solar Chromospheric Jets Associated with Emerging Flux  

Science Journals Connector (OSTI)

......present a schematic diagram summarizing the acceleration...and compressible MHD equations in Cartesian...emerging flux using a 2D MHD simulation. It is...present a schematic diagram summarizing the acceleration...Fig. 17 Schematic diagrams of the generation...region. This is an MHD effect that cannot......

Shinsuke Takasao; Hiroaki Isobe; Kazunari Shibata

2013-06-25T23:59:59.000Z

174

Numerical simulation of three-dimensional electrical flow through geomaterials  

E-Print Network (OSTI)

properties of geomaterials; to locate subsurface anomalies; and to detect and delineate subsurface contamination. Several geophysical techniques that measure the electrical resistivity of the geomaterials to quantify variation of electrical properties... geophysical resistivity analytical solutions. Comparisons are also made with an analytical solution for electrical flow around a cone penetrometer. The excellent agreement between the simulation and analytical solutions shows that the proposed methodology...

Akhtar, Anwar Saeed

2012-06-07T23:59:59.000Z

175

Numerical simulation of oscillating magnetospheres with resistive electrodynamics  

E-Print Network (OSTI)

We present a model of the magnetosphere around an oscillating neutron star. The electromagnetic fields are numerically solved by modeling electric charge and current induced by the stellar torsional mode, with particular emphasis on outgoing radiation passing through the magnetosphere. The current is modeled using Ohm's law, whereby an increase in conductivity results in an increase in the induced current. As a result, the fields are drastically modified, and energy flux is thereby enhanced. This behavior is however localized in the vicinity of the surface since the induced current disappears outwardly in our model, in which the exterior is assumed to gradually approach a vacuum.

Kojima, Yasufumi

2014-01-01T23:59:59.000Z

176

Numerical simulation of optical feedback on a quantum dot lasers  

SciTech Connect

We use multi-population rate equations model to study feedback oscillations in the quantum dot laser. This model takes into account all peculiar characteristics in the quantum dots such as inhomogeneous broadening of the gain spectrum, the presence of the excited states on the quantum dot and the non-confined states due to the presence of wetting layer and the barrier. The contribution of quantum dot groups, which cannot follow by other models, is simulated. The results obtained from this model show the feedback oscillations, the periodic oscillations which evolves to chaos at higher injection current of higher feedback levels. The frequency fluctuation is attributed mainly to wetting layer with a considerable contribution from excited states. The simulation shows that is must be not using simple rate equation models to express quantum dots working at excited state transition.

Al-Khursan, Amin H., E-mail: ameen_2all@yahoo.com [Thi-Qar University, Nassiriya Nanotechnology Research Laboratory (NNRL), Science College (Iraq); Ghalib, Basim Abdullattif [Babylon University, Laser Physics Department, Science College for Women (Iraq); Al-Obaidi, Sabri J. [Al-Mustansiriyah University, Physics Department, Science College (Iraq)

2012-02-15T23:59:59.000Z

177

The numerical simulation of liquid sloshing on board spacecraft  

Science Journals Connector (OSTI)

The subject of study is the influence of sloshing liquid on the dynamics of spacecraft. A combined theoretical and experimental approach has been followed. On the one hand, CFD simulations have been carried out to predict the combined liquid/solid body ... Keywords: 45.20.D-, 47.11.-j, 47.55.N-, Computational fluid dynamics, Free-surface flow, Microgravity, Sloshing, Sloshsat FLEVO, Solid-liquid interaction, Spacecraft dynamics

A. E. P. Veldman; J. Gerrits; R. Luppes; J. A. Helder; J. P. B. Vreeburg

2007-05-01T23:59:59.000Z

178

Numerical simulation of detonation processes in a variable cross-section chamber  

E-Print Network (OSTI)

Numerical simulation of detonation processes in a variable cross-section chamber H Y Fan and F K Lu for publication on 8 November 2007. DOI: 10.1243/09544100JAERO272 Abstract: The detonation processes occurring mechanism is used. Two detonation cases are simulated, corresponding to initiation from the closed, left end

Texas at Arlington, University of

179

A Numerical Model for the Dynamic Simulation of a Recirculation Single-Effect Absorption Chiller  

E-Print Network (OSTI)

A Numerical Model for the Dynamic Simulation of a Recirculation Single- Effect Absorption Chiller A dynamic model for the simulation of a new single-effect water/lithium bromide absorption chiller. Keywords: absorption; chiller; modelling; transient; water-lithium bromide; falling film hal-00713904

Paris-Sud XI, Université de

180

EXPLICIT SIMULATION OF ICE PARTICLE HABITS IN A NUMERICAL WEATHER PREDICTION MODEL  

E-Print Network (OSTI)

EXPLICIT SIMULATION OF ICE PARTICLE HABITS IN A NUMERICAL WEATHER PREDICTION MODEL by Tempei This study develops a scheme for explicit simulation of ice particle habits in Cloud Resolving Models (CRMs is called Spectral Ice Habit Prediction System (SHIPS), which represents a continuous-property approach

Wisconsin at Madison, University of

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Simple numerical simulation for liquid dominated geothermal reservoir  

SciTech Connect

A numerical model for geothermal reservoir has been developed. The model used is based on an idealized, two-dimensional case, where the porous medium is isotropic, nonhomogeneous, filled with saturated liquid. The fluids are assumed to have constant and temperature dependent viscosity. A Boussinesq approximation and Darcy`s law are used. The model will utilize a simple hypothetical geothermal system, i.e. graben within horsts structure, with three layers of different permeabilities. Vorticity plays an importance roles in the natural convection process, and its generation and development do not depend only on the buoyancy, but also on the magnitude and direction relation between the flow velocity and the local gradient of permeability to viscosity ratio. This model is currently used together with a physical, scaled-down reservoir model to help conceptual modeling.

Wintolo, D.; Sutrisno; Sudjamiko [Gadjah Mada Univ., Yogyakarta (Indonesia)] [and others

1996-12-31T23:59:59.000Z

182

Simple numerical simulation for liquid dominated geothermal reservoir  

SciTech Connect

A numerical model for geothermal reservoir has been developed. The model used is based on an idealized, two-dimensional case, where the porous medium is isotropic, nonhomogeneous, filled with saturated liquid. The fluids are assumed to have constant and temperature dependent viscosity. A Boussinesq approximation and Darcys law are used. The model will utilize a simple hypothetical geothermal system, i.e. graben within horsts structure, with three layers of different permeabilities. Vorticity plays an importance roles in the natural convection process, and its generation and development do not depend only on the buoyancy, but also on the magnitude and direction relation between the flow velocity and the local gradient of permeability to viscosity ratio. This model is currently used together with a physical, scaled-down reservoir model to help conceptual modeling.

Wintolo, Djoko; Sutrisno; Sudjatmiko; Sudarman, S.

1996-01-24T23:59:59.000Z

183

Numerical Simulations of Leakage from Underground LPG Storage Caverns  

SciTech Connect

To secure a stable supply of petroleum gas, underground storage caverns for liquified petroleum gas (LPG) are commonly used in many countries worldwide. Storing LPG in underground caverns requires that the surrounding rock mass remain saturated with groundwater and that the water pressure be higher than the liquid pressure inside the cavern. In previous studies, gas containment criteria for underground gas storage based on hydraulic gradient and pressure have been discussed, but these studies do not consider the physicochemical characteristics and behavior of LPG such as vaporization and dissolution in groundwater. Therefore, while these studies are very useful for designing storage caverns, they do not provide better understanding of the either the environmental effects of gas contamination or the behavior of vaporized LPG. In this study, we have performed three-phase fluid flow simulations of gas leakage from underground LPG storage caverns, using the multiphase multicomponent nonisothermal simulator TMVOC (Pruess and Battistelli, 2002), which is capable of solving the three-phase nonisothermal flow of water, gas, and a multicomponent mixture of volatile organic chemicals (VOCs) in multidimensional heterogeneous porous media. A two-dimensional cross-sectional model resembling an actual underground LPG facility in Japan was developed, and gas leakage phenomena were simulated for three different permeability models: (1) a homogeneous model, (2) a single-fault model, and (3) a heterogeneous model. In addition, the behavior of stored LPG was studied for the special case of a water curtain suddenly losing its function because of operational problems, or because of long-term effects such as clogging of boreholes. The results of the study indicate the following: (1) The water curtain system is a very powerful means for preventing gas leakage from underground storage facilities. By operating with appropriate pressure and layout, gas containment can be ensured. (2) However , in highly heterogeneous media such as fractured rock and fault zones, local flow paths within which the gas containment criterion is not satisfied could be formed. To eliminate such zones, treatments such as pre/post grouting or an additional installment of water-curtain boreholes are essential. (3) Along highly conductive features such as faults, even partially saturated zones possess certain effects that can retard or prevent gas leakage, while a fully unsaturated fault connected to the storage cavern can quickly cause a gas blowout. This possibility strongly suggests that ensuring water saturation of the rock surrounding the cavern is a very important requirement. (4) Even if an accident should suddenly impair the water curtain, the gas plume does not quickly penetrate the ground surface. In these simulations, the plume takes several months to reach the ground surface.

Yamamoto, Hajime; Pruess, Karsten

2004-09-01T23:59:59.000Z

184

Numerical simulation of waveguides of arbitrary cross section.  

SciTech Connect

Finite difference equations are derived for the simulation of dielectric waveguides using an H{sub z}-E{sub z} formulation defined on a nonuniform triangular grid. The resulting equations may be solved as a banded eigenproblem for waveguide structures of arbitrary shape composed of regions of piecewise constant isotropic dielectric, and all transverse fields then computed from the solutions. Benchmark comparisons are presented for problems with analytic solutions, as well as a sample calculation of the propagation loss of a hollow Bragg fiber.

Hadley, G. Ronald

2003-09-01T23:59:59.000Z

185

STELLAR DYNAMOS AND CYCLES FROM NUMERICAL SIMULATIONS OF CONVECTION  

SciTech Connect

We present a series of kinematic axisymmetric mean-field ?? dynamo models applicable to solar-type stars, for 20 distinct combinations of rotation rates and luminosities. The internal differential rotation and kinetic helicity profiles required to calculate source terms in these dynamo models are extracted from a corresponding series of global three-dimensional hydrodynamical simulations of solar/stellar convection, so that the resulting dynamo models end up involving only one free parameter, namely, the turbulent magnetic diffusivity in the convecting layers. Even though the ?? dynamo solutions exhibit a broad range of morphologies, and sometimes even double cycles, these models manage to reproduce relatively well the observationally inferred relationship between cycle period and rotation rate. On the other hand, they fail in capturing the observed increase of magnetic activity levels with rotation rate. This failure is due to our use of a simple algebraic ?-quenching formula as the sole amplitude-limiting nonlinearity. This suggests that ?-quenching is not the primary mechanism setting the amplitude of stellar magnetic cycles, with magnetic reaction on large-scale flows emerging as the more likely candidate. This inference is coherent with analyses of various recent global magnetohydrodynamical simulations of solar/stellar convection.

Dub, Caroline; Charbonneau, Paul, E-mail: dube@astro.umontreal.ca, E-mail: paulchar@astro.umontreal.ca [Dpartement de Physique, Universit de Montral, C.P. 6128 Succ. Centre-ville, Montral, QC H3C 3J7 (Canada)

2013-09-20T23:59:59.000Z

186

Study on Applicability of Numerical Simulation to Evaluation of Gas Entrainment From Free Surface  

SciTech Connect

An onset condition of gas entrainment (GE) due to free surface vortex has been studied to establish a design of fast breeder reactor with higher coolant velocity than conventional designs, because the GE might cause the reactor operation instability and therefore should be avoided. The onset condition of the GE has been investigated experimentally and theoretically, however, dependency of the vortex type GE on local geometry configuration of each experimental system and local velocity distribution has prevented researchers from formulating the universal onset condition of the vortex type GE. A real scale test is considered as an accurate method to evaluate the occurrence of the vortex type GE, but the real scale test is generally expensive and not useful in the design study of large and complicated FBR systems, because frequent displacement of inner equipments accompanied by the design change is difficult in the real scale test. Numerical simulation seems to be promising method as an alternative to the real scale test. In this research, to evaluate the applicability of the numerical simulation to the design work, numerical simulations were conducted on the basic experimental system of the vortex type GE. This basic experiment consisted of rectangular flow channel and two important equipments for vortex type GE in the channel, i.e. vortex generation and suction equipments. Generated vortex grew rapidly interacting with the suction flow and the grown vortex formed a free surface dent (gas core). When the tip of the gas core or the bubbles detached from the tip of the gas core reached the suction mouth, the gas was entrained to the suction tube. The results of numerical simulation under the experimental conditions were compared to the experiment in terms of velocity distributions and free surface shape. As a result, the numerical simulation showed qualitatively good agreement with experimental data. The numerical simulation results were similar to the experimental results in terms of the shape of free surface dent and the velocity distribution around the vortex, although the GE itself was not completely reproduced due to a lack of enough mesh partition. After confirming the applicability of the numerical simulation to the GE evaluation, several parameters, such as suction velocity and a configuration around suction mouth, were numerically examined to evaluate their influence on the GE. The tendencies of the GE occurrence enhanced by larger suction velocity or suction mouth on bottom surface enhance occurrence of the GE were obtained from the simulation results. These simulation results implied that the numerical simulation has enough potential to be used for the design work. (authors)

Kei Ito; Takaaki Sakai; Hiroyuki Ohshima [Japan Atomic Energy Agency (Japan)

2006-07-01T23:59:59.000Z

187

Numerical Simulations of Radiatively-Driven Dusty Winds  

E-Print Network (OSTI)

Radiation pressure on dust grains may be an important mechanism in driving winds in a wide variety of astrophysical systems. However, the efficiency of the coupling between the radiation field and the dusty gas is poorly understood in environments characterized by high optical depths like those in ultra-luminous infrared galaxies (ULIRGs) and massive dense star clusters. We present a series of idealized numerical experiments, performed with the radiation-hydrodynamic code \\textsc{orion}, in which we study the dynamics of such winds and quantify their properties. We find that, after wind acceleration begins, radiation Rayleigh-Taylor instability forces the gas into a configuration that reduces the rate of momentum transfer from the radiation field to the gas by a factor ~ 10 - 100 compared to an estimate based on the optical depth at the base of the atmosphere; instead, the rate of momentum transfer from a driving radiation field of luminosity L to the gas is roughly L/c multiplied by half the optical depth at...

Krumholz, Mark R

2013-01-01T23:59:59.000Z

188

Numerical simulation of buoyant turbulent flow. Final report  

SciTech Connect

Two models have been developed for predicting low Reynolds number turbulent flows in the free and mixed convection regimes. One, the KEM model, is based on the notion of eddy diffusivities for momentum and heat. The other, the ASM model, is based on algebraic relations derived for the anisotropic turbulent fluxes by suitable truncation of the parent transport equations. Both formulations apply to variable property flows with high overheat ratios. A comparison between measurements and predictions for the case of the vertical plate shows that both models yield fairly accurate results for the mean flow and heat transfer. As a result, only the simpler of the two models, the KEM, was used to predict the cavity flows. Predictions for the case of the vertical flat plate show excellent agreement with measurements of mean velocity, temperature and Nusselt number. Nearwall results predicted by both models reveal the existence of a 1/3 power-law dependence. Regions of negative buoyant and shear production of turbulence kinetic energy are clearly revealed by the calculations. Calculations of the cavity configuration were performed for the free and mixed flow conditions. Fairly good agreement is obtained between measurements and predictions of the velocity and temperature fields. Many of the complex characteristics of heated cavity flows, revealed experimentally, are resolved numerically. Although differing in absolute value, calculations of the cavity Nusselt number show trends which are in accord with the measurements. Thus, in the free convection regime it is shown that when the cavity is tilted forwards stable stratification of fluid dampens the turbulence fluctuations which works to reduce heat transfer.

Humphrey, J.A.C.; Sherman, F.S.; To, W.M.

1985-08-01T23:59:59.000Z

189

Numerical simulation of borehole acoustic logging in the frequency and time domains with hp-adaptive finite elements  

E-Print Network (OSTI)

Numerical simulation of borehole acoustic logging in the frequency and time domains with hp elasticity Coupled problems hp-adaptive finite elements a b s t r a c t Accurate numerical simulation physical modeling combined with accurate and efficient numerical dis- cretization and solution techniques

Torres-Verdín, Carlos

190

Direct Numerical Simulation of Autoiginition of a Hydrogen Jet in a  

NLE Websites -- All DOE Office Websites (Extended Search)

Direct Numerical Simulation of Autoiginition of a Hydrogen Jet in a Direct Numerical Simulation of Autoiginition of a Hydrogen Jet in a Preheated Cross Flow Submitted by mkaczmar on June 4, 2013 - 13:52 Authors: Abdilghanie, A., Frouzakis, C.E., Fischer, P Autoignition of a nitrogen-diluted hydrogen mixture issuing from a round nozzle into a cross-flowing turbulent stream of preheated air flowing in a channel at a friction Reynolds number Re = 180 is inves- tigated via 3-D direct numerical simulations (DNS) at two crossflow stream temperatures (930 and 950 K). Three-dimensional visualizations of the JICF reveal a complicated flow structure characterized by a variety of coherent vortical structures resulting from the boundary layers near the walls and evolving from the jet instabilities. The mean pressure field set up by the flow

191

Numerical simulation of frontal rainbands over Ukraine under different mechanisms of cloud and precipitation formation  

Science Journals Connector (OSTI)

Three-dimension diagnostic and prognostic models were used for numerical simulation of cloud system accompanied the passage of a cyclone over Ukraine. The response of time and space distribution of cloud particle spectra integral features and precipitation on changing of cloud and precipitation formation mechanisms (condensation sublimation collection by large drop and ice particles for droplets etc) was investigated. The nested and stretched grid was used to simulate the narrow band of heavy rainfall that frequently appeared ahead a cold front. The numerical experiments for different values of cloud condensation nucleus concentration were carried out for the above rainband. Comparison between spectra for different conditions was performed.

A. M. Pirnach; S. V. Krakovskaia; A. V. Belokobylski

2000-01-01T23:59:59.000Z

192

Numerical Simulation of the Irish Wind Climate and Comparison with Wind  

Open Energy Info (EERE)

Numerical Simulation of the Irish Wind Climate and Comparison with Wind Numerical Simulation of the Irish Wind Climate and Comparison with Wind Atlas Data Dataset Summary Description (Abstract): The wind climate of Ireland has been calculated using the Karlsruhe Atmospheric Mesoscale Model KAMM using the statistical-dynamical method. The large-scale climatology is represented by 65 classes of geostropic wind. From the frequency of the classes and the simulations the climatology of the surface wind is determined. The simulated winds are processed similar to observed data to obtain LIB-files for the Wind Atlas Analysis and Application Program WAsP. Comparisons are made with mast observations which have been analyzed by WAsP. Sites with high wind power potential are well predicted. Stations with low power are over predicted. (Purpose): Article describing an example of a KAMM

193

Numerical Simulation of the December 26, 2004 Indian Ocean Tsunami using a Higher-order Boussinesq Model  

E-Print Network (OSTI)

Numerical Simulation of the December 26, 2004 Indian Ocean Tsunami using a Higher-order Boussinesq of the tsunami, with a higher-order Boussinesq model. We find reasonable agreement of numerical results

Grilli, Stéphan T.

194

Simulation of Store Separation Scaling Requirements for Wind Tunnel Experiments and Validation of Numerical Simulations  

Science Journals Connector (OSTI)

The results of experimental and numerical investigations on cargo drop tests from a generic military transport aircraft configuration with open cargo bay are presented. The governing equations for experimental sc...

N. Schade

2013-01-01T23:59:59.000Z

195

EulerianEulerian two-phase numerical simulation of nanofluid laminar forced convection in a microchannel  

E-Print Network (OSTI)

by a cooling system to guarantee their appropriate performance. One possible way to cool these devises canEulerian­Eulerian two-phase numerical simulation of nanofluid laminar forced convection August 2010 Accepted 5 August 2010 Keywords: Nanofluid Microchannel Two-phase Laminar Heat transfer a b

Harting, Jens

196

American Institute of Aeronautics and Astronautics Numerical Simulation of H2/Air Detonation Using Detailed  

E-Print Network (OSTI)

- 1 - American Institute of Aeronautics and Astronautics Numerical Simulation of H2/Air Detonation of detonation, and 3-D computation of detonation propagating in a tube with a spiral obstacle was conducted. Introduction A detonation is a shock wave sustained by the energy released by combustion. The typical case

Löhner, Rainald

197

Mon. Not. R. Astron. Soc. 319, 721727 (2000) In-shock cooling in numerical simulations  

E-Print Network (OSTI)

are especially interested in the production of molecular hydrogen, and so we follow the ionization level and H2 the rate of molecular hydrogen (H2) and hydrogen-deuterium (HD) production. These two molecules waves ± methods: numerical. 1 I NTRO DUC TION For hydrodynamics codes to be able to simulate shocks

Thomas, Peter

198

Numeric Simulation of Heat Transfer and Electrokinetic Flow in an Electroosmosis-Based  

E-Print Network (OSTI)

Numeric Simulation of Heat Transfer and Electrokinetic Flow in an Electroosmosis-Based Continuous is dedicated to under- standing the fluid flow and heat transfer mechanisms occurring in continuous flow PCR are discussed in detail. The importance of each heat transfer mechanism for different situations is also

Le Roy, Robert J.

199

Numerical simulations of heat transfer in plane channel flow Najla EL GHARBI 1, 3, a  

E-Print Network (OSTI)

Numerical simulations of heat transfer in plane channel flow Najla EL GHARBI 1, 3, a , Rafik ABSI 2 abenzaoui@gmail.com Keywords: turbulent flows, heat transfer, forced convection, low Reynolds number model data for Re = 150. Introduction Turbulent flow with heat transfer mechanism is of great importance from

Paris-Sud XI, Université de

200

Numerical simulation of internal tides and the resulting energetics within Monterey Bay and the surrounding area  

E-Print Network (OSTI)

tides are generated at critical topography and observe that most of the energy propagates into the Mon. These results are used to compute internal tide energy flux and energy flux divergence to analyze internal tideNumerical simulation of internal tides and the resulting energetics within Monterey Bay

Fringer, Oliver B.

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Steam generators two phase flows numerical simulation with liquid and gas momentum equations  

E-Print Network (OSTI)

Steam generators two phase flows numerical simulation with liquid and gas momentum equations M Abstract This work takes place in steam generators flow studies and we consider here steady state three words: Steam Generator, Two-phase Flow, Finite element Email address: Marc.Grandotto@cea.fr (M

Paris-Sud XI, Université de

202

Numerical simulation of noise generated by multi asperity contact between rough surfaces  

E-Print Network (OSTI)

. The validation of the method is then discussed by comparison with the finite element software Abaqus and someNumerical simulation of noise generated by multi asperity contact between rough surfaces V.H. Dang at the interface that convert a part of the kinetic energy of the sliding solid into acoustical energy. 1

Paris-Sud XI, Université de

203

Comm. Nonlin. Sci Numer. Simul. 13, (2008), 1256-1263. Discrepancy principle for DSM II  

E-Print Network (OSTI)

Comm. Nonlin. Sci Numer. Simul. 13, (2008), 1256-1263. 1 #12;Discrepancy principle for DSM II A versions of discrepancy principles for the DSM (dynamical systems method) for finding the stopping time of the discrepancy principle for DSM was proved. This version con- sisted in solving the equation for t: ||T-1 a

204

Numerical simulations of the thermal impact of supercritical CO2 injection on chemical  

E-Print Network (OSTI)

technology must make it possible to inject CO2 into deep saline aquifers or oil- and gas-depleted reservoirs by massive CO2 injection. If laboratory or field experiments can bring many details about gas behaviourNumerical simulations of the thermal impact of supercritical CO2 injection on chemical reactivity

Boyer, Edmond

205

PHYSICS OF FLUIDS 24, 103306 (2012) Numerical simulation of turbulent sediment transport,  

E-Print Network (OSTI)

PHYSICS OF FLUIDS 24, 103306 (2012) Numerical simulation of turbulent sediment transport, from bed October 2012) Sediment transport is studied as a function of the grain to fluid density ratio using two), vertical velocities are so small that sediment transport occurs in a thin layer at the surface

Claudin, Philippe

206

DIVERGENCE-FREE AND CURL-FREE WAVELETS ON THE SQUARE FOR NUMERICAL SIMULATIONS  

E-Print Network (OSTI)

DIVERGENCE-FREE AND CURL-FREE WAVELETS ON THE SQUARE FOR NUMERICAL SIMULATIONS SOULEYMANE KADRI Grenoble cedex 9, France August 30, 2011 Abstract We present a construction of divergence-free and curl-free and integration. We introduce new BMRAs and wavelets for the spaces of divergence-free and curl-free vector

Boyer, Edmond

207

Numerical simulation of ice-induced loads on ships and comparison with field measurements  

E-Print Network (OSTI)

Department of Marine Technology, NTNU May 28, 2013 #12;Motivation Local ice load Global ice load ShipNumerical simulation of ice-induced loads on ships and comparison with field measurements Biao Su's performance · Ice-hull interaction · Local ice load · Global ice load · Ship's performance #12;Outline

Nørvåg, Kjetil

208

Maneuverability of ships in ice: numerical simulation and comparison with field measurements  

E-Print Network (OSTI)

Maneuverability of ships in ice: numerical simulation and comparison with field measurements Biao Su Department of Marine Technology, NTNU May 28, 2013 #12;Motivation Local ice load Global ice load Ship's performance · Ice-hull interaction · Local ice load · Global ice load · Ship's performance #12

Nørvåg, Kjetil

209

Energy Production, Frictional Dissipation, and Maximum Intensity of a Numerically Simulated Tropical Cyclone  

E-Print Network (OSTI)

0 Energy Production, Frictional Dissipation, and Maximum Intensity of a Numerically Simulated) viewed as a heat engine converts heat energy extracted from the ocean to kinetic energy of the TC, which is eventually dissipated due to surface friction. Since the energy production rate is a linear function while

Wang, Yuqing

210

Energy Production, Frictional Dissipation, and Maximum Intensity of a Numerically Simulated Tropical Cyclone*  

E-Print Network (OSTI)

Energy Production, Frictional Dissipation, and Maximum Intensity of a Numerically Simulated as a heat engine converts heat energy extracted from the ocean into the kinetic energy of the TC, which is eventually dissipated due to surface friction. Since the energy production rate is a linear function while

Wang, Yuqing

211

Observations and Numerical Simulations of Urban Heat Island and Sea Breeze Circulations over New York City  

E-Print Network (OSTI)

-level pollutant dispersion. When an urban area is located at the coast of a large body of water, complexitiesObservations and Numerical Simulations of Urban Heat Island and Sea Breeze Circulations over New examined during several synoptic scale flow regimes over New York City after the World Trade Center

Raman, Sethu

212

Numerical simulation of air/water multiphase flows for ceramic sanitary ware design by multiple GPUs  

E-Print Network (OSTI)

and kitchen fittings. Facing the increasing demands for saving energy and water, TOTO has always targeted schemes and port the code to the GPU platforms to accelerate the large scale computations for real** Tokyo Institute of Technology, Department of energy sciences Numerical simulation of air

Furui, Sadaoki

213

Numerical Simulation of 1993 July 12 Tsunami Near Hokkaido; Its Propagation and Flooding onto Aonae District, Okushiri Island  

Science Journals Connector (OSTI)

A numerical simulations of the 1993 South-West Off Hokkaido ... a low angle. The mechanism of tsunami flooding onto Aonae district, Okushiri island, was also made clear by the simulation in which shoaling and ref...

T. Yamashita; T. Takabayashi; Y. Tsuchiya

1997-01-01T23:59:59.000Z

214

Hydraulic model and steam flow numerical simulation of the Cerro Prieto geothermal field, Mexico, pipeline network  

Science Journals Connector (OSTI)

Abstract The development of a hydraulic model and numerical simulation results of the Cerro Prieto geothermal field (CPGF) steam pipeline network are presented. Cerro Prieto is the largest water-dominant geothermal field in the world and its transportation network has 162 producing wells, connected through a network of pipelines that feeds 13 power-generating plants with an installed capacity of 720MWe. The network is about 125km long and has parallel high- and low-pressure networks. Prior to this study, it was suspected that steam flow stagnated or reversed from its planned direction in some segments of the network. Yet, the network complexity and extension complicated the analysis of steam transport for adequate delivery to the power plants. Thus, a hydraulic model of the steam transportation system was developed and implemented numerically using an existing simulator, which allowed the overall analysis of the network in order to quantify the pressure and energy losses as well as the steam flow direction in every part of the network. Numerical results of the high-pressure network were obtained which show that the mean relative differences between measured and simulated pressures and flowrates are less than 10%, which is considered satisfactory. Analysis of results led to the detection of areas of opportunity and to the recommendation of changes for improving steam transport. A main contribution of the present work is having simulated satisfactorily the longest (to our knowledge), and probably the most complex, steam pipeline network in the world.

A. Garca-Gutirrez; A.F. Hernndez; J.I. Martnez; M. Ceceas; R. Ovando; I. Canchola

2015-01-01T23:59:59.000Z

215

Four-Dimensional Assimilation of Multitime Wind Profiles over a Single Station and Numerical Simulation of a Mesoscale Convective  

E-Print Network (OSTI)

on the numerical simulation of the convective initiation and evolution. Besides the wind fields, the structureFour-Dimensional Assimilation of Multitime Wind Profiles over a Single Station and Numerical Simulation of a Mesoscale Convective System Observed during IHOP_2002 LEI ZHANG AND ZHAOXIA PU Department

Pu, Zhaoxia

216

A Shallow Water model for the numerical simulation of overland flow on surfaces with ridges and furrows  

E-Print Network (OSTI)

A Shallow Water model for the numerical simulation of overland flow on surfaces with ridges Abstract We introduce a new Shallow Water model for the numerical simulation of overland flow with furrow conservation (decreases soil thickness by erosion and causes nutrient loss), infrastruc- tures (flooding

d'Orléans, Université

217

Development of a Numerical Simulator for Analyzing the Geomechanical Performance of Hydrate-Bearing Sediments  

SciTech Connect

In this paper, we describe the development and application of a numerical simulator that analyzes the geomechanical performance of hydrate-bearing sediments, which may become an important future energy supply. The simulator is developed by coupling a robust numerical simulator of coupled fluid flow, hydrate thermodynamics, and phase behavior in geologic media (TOUGH+HYDRATE) with an established geomechanical code (FLAC3D). We demonstrate the current simulator capabilities and applicability for two examples of geomechanical responses of hydrate bearing sediments during production-induced hydrate dissociation. In these applications, the coupled geomechanical behavior within hydrate-bearing seducements are considered through a Mohr-Coulomb constitutive model, corrected for changes in pore-filling hydrate and ice content, based on laboratory data. The results demonstrate how depressurization-based gas production from oceanic hydrate deposits may lead to severe geomechanical problems unless care is taken in designing the production scheme. We conclude that the coupled simulator can be used to design production strategies for optimizing production, while avoiding damaging geomechanical problems.

Rutqvist, Jonny; Rutqvist, J.; Moridis, G.J.

2008-06-01T23:59:59.000Z

218

Modelling and Numerical Simulation of Gas Migration in a Nuclear Waste Repository  

E-Print Network (OSTI)

We present a compositional compressible two-phase, liquid and gas, flow model for numerical simulations of hydrogen migration in deep geological radioactive waste repository. This model includes capillary effects and the gas diffusivity. The choice of the main variables in this model, Total or Dissolved Hydrogen Mass Concentration and Liquid Pressure, leads to a unique and consistent formulation of the gas phase appearance and disappearance. After introducing this model, we show computational evidences of its adequacy to simulate gas phase appearance and disappearance in different situations typical of underground radioactive waste repository.

Bourgeat, Alain; Smai, Farid

2010-01-01T23:59:59.000Z

219

Comparison of Numerical Simulators for Greenhouse Gas Storage in Coalbeds, Part I: Pure Carbon Dioxide Injection  

NLE Websites -- All DOE Office Websites (Extended Search)

Comparison of Numerical Simulators for Greenhouse Gas Storage Comparison of Numerical Simulators for Greenhouse Gas Storage in Coalbeds, Part I: Pure Carbon Dioxide Injection David H.-S. Law (law@arc.ab.ca; 780-450-5034) Alberta Research Council (ARC) Inc. 250 Karl Clark Road, Edmonton, Alberta, Canada T6N 1E4 L.H.G. (Bert) van der Meer (l.vandermeer@nitg.tno.nl; +31-30-256-4635) Netherlands Institute of Applied Geoscience TNO P.O. Box 80015, 3508 TA Utrecht, The Netherlands W.D. (Bill) Gunter (gunter@arc.ab.ca; 780-450-5467) Alberta Research Council (ARC) Inc. 250 Karl Clark Road, Edmonton, Alberta, Canada T6N 1E4 Abstract The injection of carbon dioxide (CO 2 ) in deep, unmineable coalbeds is a very attractive option for geologic CO 2 storage: the CO 2 is stored and at the same time the recovery of

220

Direct Numerical Simulations of Nonlinear Evolution of MHD Instability in LHD  

SciTech Connect

Nonlinear evolutions of MHD instabilities in the large helical device are studied by means of direct numerical simulations under the vacuum configuration with the magnetic axis position R = 3.6m, including effects of its full three-dimensional geometry, flows parallel to the magnetic field lines and the fluid compressibility. The linear growth of the pressure-driven modes and their nonlinear saturations are observed. The linear growth brings about the flows parallel to the magnetic field lines as strong as the perpendicular flows. The fluid compressibility reduces the linear growth rate significantly. In the nonlinear saturation process, a qualitative difference is found in the behaviors of the parallel and perpendicular flows. The plasma appears to approach to a near-equilibrium state, keeping finite amplitudes of the parallel flow. Our numerical results highlight important roles of the parallel flow and compressibility in nonlinear MHD simulations in the large helical device.

Miura, H.; Nakajima, N.; Hayashi, T. [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Department of Fusion Science, The Graduate University for Advanced Studies (SOKENDAI), 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Okamoto, M. [Department of Information Science, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501 (Japan)

2006-11-30T23:59:59.000Z

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Numerical Code Comparison Project - A Necessary Step Towards Confidence in Geothermal Reservoir Simulators  

SciTech Connect

A necessary first step in resolving differences and in evaluating the usefulness of numerical simulators for geothermal reservoir analysis is the comparison of simulator results for a set of well-specified problems involving processes applicable in reservoir analysis. Under the direction of DOE'S Geothermal Reservoir Engineering Management Program (GREMP), a set of six test problems has been developed in an attempt to meet this need. The problem set covers a range of reservoir situations including single- and two-phase flow under 1, 2, and 3 dimensional conditions. Each problem has been test run to insure that the parameter specifications will yield workable solutions, and in several cases analytical solutions are available for comparison. Brief descriptions of the problems are given in each problem, the desired grid and time-step sizes were specified to minimize differences in results due to numerical discretization.

Sorey, Michael L.

1980-12-16T23:59:59.000Z

222

An Efficient Numerical Scheme for Simulating Unidirectional Irregular Waves Based on a Hybrid Wave Model  

E-Print Network (OSTI)

................................................................................ 40 Table 4 NREL 5-MW wind turbine characteristics ................................................ 41 Table 5 Hywind-OC3 Spar dimensions .................................................................. 41 Table 6 Mooring system properties...) for computing the wind loads on a wind turbine. A 5MW wind turbine installed on the top of a classical Spar (Hywind-OC3 Spar) is employed to demonstrate the simulation. The 39 numerical results derived in this study may provide crucial information...

Jia, Dongxing 1984-

2012-11-15T23:59:59.000Z

223

Assessment of high-resolution methods for numerical simulations of compressible turbulence with shock waves  

SciTech Connect

Flows in which shock waves and turbulence are present and interact dynamically occur in a wide range of applications, including inertial confinement fusion, supernovae explosion, and scramjet propulsion. Accurate simulations of such problems are challenging because of the contradictory requirements of numerical methods used to simulate turbulence, which must minimize any numerical dissipation that would otherwise overwhelm the small scales, and shock-capturing schemes, which introduce numerical dissipation to stabilize the solution. The objective of the present work is to evaluate the performance of several numerical methods capable of simultaneously handling turbulence and shock waves. A comprehensive range of high-resolution methods (WENO, hybrid WENO/central difference, artificial diffusivity, adaptive characteristic-based filter, and shock fitting) and suite of test cases (Taylor-Green vortex, Shu-Osher problem, shock-vorticity/entropy wave interaction, Noh problem, compressible isotropic turbulence) relevant to problems with shocks and turbulence are considered. The results indicate that the WENO methods provide sharp shock profiles, but overwhelm the physical dissipation. The hybrid method is minimally dissipative and leads to sharp shocks and well-resolved broadband turbulence, but relies on an appropriate shock sensor. Artificial diffusivity methods in which the artificial bulk viscosity is based on the magnitude of the strain-rate tensor resolve vortical structures well but damp dilatational modes in compressible turbulence; dilatation-based artificial bulk viscosity methods significantly improve this behavior. For well-defined shocks, the shock fitting approach yields good results.

Johnsen, Eric [Center for Turbulence Research, Stanford University, Stanford, CA 94305 (United States)], E-mail: johnsen@stanford.edu; Larsson, Johan [Center for Turbulence Research, Stanford University, Stanford, CA 94305 (United States)], E-mail: jola@stanford.edu; Bhagatwala, Ankit V. [Department of Aeronautics and Astronautics, Stanford University, Stanford, CA 94305 (United States); Cabot, William H. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Moin, Parviz [Center for Turbulence Research, Stanford University, Stanford, CA 94305 (United States); Olson, Britton J. [Department of Aeronautics and Astronautics, Stanford University, Stanford, CA 94305 (United States); Rawat, Pradeep S. [Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, CA 90095 (United States); Shankar, Santhosh K. [Department of Aeronautics and Astronautics, Stanford University, Stanford, CA 94305 (United States); Sjoegreen, Bjoern [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Yee, H.C. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Zhong Xiaolin [Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, CA 90095 (United States); Lele, Sanjiva K. [Department of Aeronautics and Astronautics, Stanford University, Stanford, CA 94305 (United States)

2010-02-20T23:59:59.000Z

224

Numerical simulation of supercritical heat transfer under severe axial density gradient in a narrow vertical tube  

SciTech Connect

A number of computational works have been performed so far for the simulation of heat transfer in a supercritical fluid. The simulations, however, faced a lot of difficulties when heat transfer deteriorates due either to buoyancy or by acceleration. When the bulk temperature approaches the pseudo-critical temperature the fluid experiences a severe axial density gradient on top of a severe radial one. Earlier numerical calculations showed, without exception, unrealistic over-predictions, as soon as the bulk temperature exceeded the pseudo-critical temperature. The over-predictions might have been resulted from an inapplicability of widely-used turbulence models. One of the major causes for the difficulties may probably be an assumption of a constant turbulent Prandtl number. Recent research, both numerical and experimental, indicates that the turbulent Prandtl number is never a constant when the gradient of physical properties is significant. This paper describes the applicability of a variable turbulent Prandtl number to the numerical simulation of heat transfer in supercritical fluids flowing in narrow vertical tubes. (authors)

Bae, Y. Y.; Hong, S. D.; Kim, Y. W. [Korea Atomic Energy Research Inst., 1045 Daedeokdaero, Daejeon (Korea, Republic of)

2012-07-01T23:59:59.000Z

225

Coupling a Mesoscale Numerical Weather Prediction Model with Large-Eddy Simulation for Realistic Wind Plant Aerodynamics Simulations (Poster)  

SciTech Connect

Wind plant aerodynamics are influenced by a combination of microscale and mesoscale phenomena. Incorporating mesoscale atmospheric forcing (e.g., diurnal cycles and frontal passages) into wind plant simulations can lead to a more accurate representation of microscale flows, aerodynamics, and wind turbine/plant performance. Our goal is to couple a numerical weather prediction model that can represent mesoscale flow [specifically the Weather Research and Forecasting model] with a microscale LES model (OpenFOAM) that can predict microscale turbulence and wake losses.

Draxl, C.; Churchfield, M.; Mirocha, J.; Lee, S.; Lundquist, J.; Michalakes, J.; Moriarty, P.; Purkayastha, A.; Sprague, M.; Vanderwende, B.

2014-06-01T23:59:59.000Z

226

Numerical simulation of swirling flow in complex hydroturbine draft tube using unsteady statistical turbulence models  

SciTech Connect

A numerical method is developed for carrying out unsteady Reynolds-averaged Navier-Stokes (URANS) simulations and detached-eddy simulations (DESs) in complex 3D geometries. The method is applied to simulate incompressible swirling flow in a typical hydroturbine draft tube, which consists of a strongly curved 90 degree elbow and two piers. The governing equations are solved with a second-order-accurate, finite-volume, dual-time-stepping artificial compressibility approach for a Reynolds number of 1.1 million on a mesh with 1.8 million nodes. The geometrical complexities of the draft tube are handled using domain decomposition with overset (chimera) grids. Numerical simulations show that unsteady statistical turbulence models can capture very complex 3D flow phenomena dominated by geometry-induced, large-scale instabilities and unsteady coherent structures such as the onset of vortex breakdown and the formation of the unsteady rope vortex downstream of the turbine runner. Both URANS and DES appear to yield the general shape and magnitude of mean velocity profiles in reasonable agreement with measurements. Significant discrepancies among the DES and URANS predictions of the turbulence statistics are also observed in the straight downstream diffuser.

Paik, Joongcheol [University of Minnesota; Sotiropoulos, Fotis [University of Minnesota; Sale, Michael J [ORNL

2005-06-01T23:59:59.000Z

227

Numerical simulation of discharge structures in Ar/Cs nonequilibrium plasma MHD generator  

SciTech Connect

As reported in previous papers, the quasi-one-dimensional simulation code has come to predict almost satisfactorily the performance of the shock tube driven disk MHD generator using cesium seeded argon plasma as working fluid. However, the agreement between experimental and predicted performances was not so good on the conditions that the external load resistance was small, the seed fraction was high or the stagnation pressure was low. On these conditions, it was observed that ionization instabilities occur in the MHD channel. On the other hand, high-speed photographs of the nonequilibrium plasma discharge in the MHD generator were taken on several working conditions during the experiment. From these photographs, discharges were classified into almost three kinds of patterns. (a) A single strong luminous ring-type discharge near the nozzle exit for low seed fraction, (b) an almost uniform discharge inside the MHD channel for medium seed fraction, (c) multiple ring-type or spiral discharges in the MHD channel for high seed fraction. The structures of the discharge were sometimes two-dimensional especially for high seed fraction. Therefore, it may be impossible in this case to simulate them and to predict the performance precisely with one-dimensional simulation code. In the present study, two-dimensional (r-q) numerical simulations were made on the disk MHD power generation experiment (thermal input is about 1.5MW). The objectives were to develop a numerical simulator with high accuracy for the disk MHD generator and to explain some interesting phenomena concerned with nonequilibrium plasma discharges. The system of basic equations was solved mainly using CIP method. The calculation region was taken as that located between the throat to the inlet of the second (final) cathode. The main results are summarized as follows; (A) On the condition that the seed fraction was lower than the optimum value, it was succeeded to simulate numerically the single strong luminous ring-type discharge. The ring-type discharge was caused by the partial ionization of argon due to the rapid increase in the electron temperature in the nozzle. The pressure increase like a shock wave was also induced there. (B) On the condition that the seed fraction was near the optimum value, an almost uniform plasma was obtained in the simulation and in the experiment. (C) On the condition that seed fraction was higher than the optimum value, A similar structure of discharge to experimental one was obtained in the calculation due to an ionization instability (streamer) caused by the partial ionization of seeded cesium. (D) The performances of the generator such as enthalpy extraction can be predicted well with this simulation code.

Okubo, M.; Kabashima, S.; Okuno, Y.; Yamasaki, H.

1998-07-01T23:59:59.000Z

228

Numerical Simulations of Pillar Structured Solid State Thermal Neutron Detector Efficiency and Gamma Discrimination  

SciTech Connect

This work reports numerical simulations of a novel three-dimensionally integrated, {sup 10}boron ({sup 10}B) and silicon p+, intrinsic, n+ (PIN) diode micropillar array for thermal neutron detection. The inter-digitated device structure has a high probability of interaction between the Si PIN pillars and the charged particles (alpha and {sup 7}Li) created from the neutron - {sup 10}B reaction. In this work, the effect of both the 3-D geometry (including pillar diameter, separation and height) and energy loss mechanisms are investigated via simulations to predict the neutron detection efficiency and gamma discrimination of this structure. The simulation results are demonstrated to compare well with the measurement results. This indicates that upon scaling the pillar height, a high efficiency thermal neutron detector is possible.

Conway, A; Wang, T; Deo, N; Cheung, C; Nikolic, R

2008-06-24T23:59:59.000Z

229

Internal wave generation by convection in water. Part 2. Numerical simulations  

E-Print Network (OSTI)

Water's density maximum at 4C makes it well suited to study internal gravity wave excitation by convection: an increasing temperature profile is unstable to convection below 4C, but stably stratified above 4C. We present numerical simulations of water near its density maximum in a two dimensional tank, similar to the experiment described in a companion paper (Le Bars et al. 2015). The simulations agree very well with the experiments, despite differences in lateral boundary conditions in the two systems. We successfully model the damping of waves in the simulations using linear theory, provided we do not take the weak damping limit typically used in the literature. In order to isolate the physical mechanism exciting internal waves, we use the novel spectral code Dedalus to run several simulations of the simulation. We use data from the full simulation as source terms in two simplified models of internal wave excitation by convection: bulk excitation by convective Reynolds stresses, and interface forcing via th...

Lecoanet, Daniel; Burns, Keaton J; Vasil, Geoffrey M; Brown, Benjamin P; Quataert, Eliot; Oishi, Jeffrey S

2014-01-01T23:59:59.000Z

230

Pattern formation and dynamics in Rayleigh-Benard convection : numerical simulations of experimentally realistic geometries.  

SciTech Connect

Rayleigh-Benard convection is studied and quantitative comparisons are made, where possible, between theory and experiment by performing numerical simulations of the Boussinesq equations for a variety of experimentally realistic situations. Rectangular and cylindrical geometries of varying aspect ratios for experimental boundary conditions, including fins and spatial ramps in plate separation, are examined with particular attention paid to the role of the mean flow. A small cylindrical convection layer bounded laterally either by a rigid wall, fin, or a ramp is investigated and our results suggest that the mean flow plays an important role in the observed wavenumber. Analytical results are developed quantifying the mean flow sources, generated by amplitude gradients, and its effect on the pattern wavenumber for a large-aspect-ratio cylinder with a ramped boundary. Numerical results are found to agree well with these analytical predictions. We gain further insight into the role of mean flow in pattern dynamics by employing a novel method of quenching the mean flow numerically. Simulations of a spiral defect chaos state where the mean flow is suddenly quenched is found to remove the time dependence, increase the wavenumber and make the pattern more angular in nature.

Paul, M. R.; Chiarn, K.-H.; Cross, M. C.; Fischer, P. F.; Greenside, H. S.; Mathematics and Computer Science; California Inst. of Tech.; Duke University

2003-10-01T23:59:59.000Z

231

Complete Numerical Simulation of Subcooled Flow Boiling in the Presence of Thermal and Chemical Interactions  

SciTech Connect

At present, guidelines for fuel cycle designs to prevent axial offset anomalies (AOA) in pressurized water reactor (PWR) cores are based on empirical data from several operating reactors. Although the guidelines provide an ad-hoc solution to the problem, a unified approach based on simultaneous modeling of thermal-hydraulics, chemical, and nuclear interactions with vapor generation at the fuel cladding surface does not exist. As a result, the fuel designs are overly constrained with a resulting economic penalty. The objective of present project is to develop a numerical simulation model supported by laboratory experiments that can be used for fuel cycle design with respect to thermal duty of the fuel to avoid economic penalty, as well as, AOA. At first, two-dimensional numerical simulation of the growth and departure of a bubble in pool boiling with chemical interaction is considered. A finite difference scheme is used to solve the equations governing conservation of mass, momentum, energy, and species concentration. The Level Set method is used to capture the evolving liquid-vapor interface. A dilute aqueous boron solution is considered in the simulation. From numerical simulations, the dynamic change in concentration distribution of boron during the bubble growth shows that the precipitation of boron can occur near the advancing and receding liquid-vapor interface when the ambient boron concentration level is 3,000 ppm by weight. Secondly, a complete three-dimensional numerical simulation of inception, growth and departure of a single bubble subjected to forced flow parallel to the heater surface was developed. Experiments on a flat plate heater with water and with boron dissolved in the water were carried out. The heater was made out of well-polished silicon wafer. Numbers of nucleation sites and their locations were well controlled. Bubble dynamics in great details on an isolated nucleation site were obtained while varying the wall superheat, liquid subcooling and flow velocity parametrically. Concentration variation of boron near the liquid-vapor interface was detected successfully with a newly developed miniature concentration sensor. The measured concentration variations at different radial locations from the center of cavity have the same trend as given by the numerical simulations. The deposition of boron was found near the nucleation site on the heater surface, which validates the numerical simulation. Subcooled flow boiling experiments at three pressures were performed on a nine-rod bundle with water and with boron dissolved in the water. The test runs were conducted with a wide range of mass fluxes (186 to 2800 kg/m2s) and heat fluxes (1.0 to 30.0 W/ cm2). Not only the variables required to develop mechanistic models for subcooled flow boiling were measured, but also the crud formation during boiling and its effect on the heat transfer process were investigated. (B204)

V.K. Dhir

2003-04-28T23:59:59.000Z

232

Local mechanical properties of LFT injection molded parts: Numerical simulations versus experiments  

Science Journals Connector (OSTI)

In predictive engineering for polymer processes the proper prediction of material microstructure from known processing conditions and constituent material properties is a critical step forward properly predicting bulk properties in the finished composite. Operating within the context of long-fiber thermoplastics (LFT length Autodesk Simulation Moldflow Insight 2014 software has been used. In this software a fiber breakage algorithm for the polymer flow inside the mold is available. Using well known micro mechanic formulas allow to combine the local fiber length with the local orientation into local mechanical properties. Different experiments were performed using a commercially available glass fiber filled compound to compare the measured data with the numerical simulation results. In this investigation tensile tests and 3 point bending tests are considered. To characterize the fiber length distribution of the polymer melt entering the mold (necessary for the numerical simulations) air shots were performed. For those air shots similar homogenization conditions were used as during the injection molding tests. The fiber length distribution is characterized using automated optical method on samples for which the matrix material is burned away. Using the appropriate settings for the different experiments good predictions of the local mechanical properties are obtained.

2014-01-01T23:59:59.000Z

233

Numerical study of ion-cyclotron resonant interaction via hybrid-Vlasov simulations  

SciTech Connect

Hybrid Vlasov-Maxwell numerical simulations are used to investigate the collisionless resonant interaction of ions with ion-cyclotron waves in parallel propagation with respect to a background magnetic field. In linear regime, analytical results on wave damping, obtained by integrating the linearized Vlasov equation through the well-known characteristics method, are compared with the numerical results. Then, the ion heating process and the consequent generation of temperature anisotropy in the direction perpendicular to the background magnetic field are investigated numerically in detail. In nonlinear regime, the numerical results show that the distribution of particle velocities is strongly distorted due to the resonant ion-cyclotron interaction with the formation of diffusive plateaus in the longitudinal direction (with respect to the ambient field) and significantly departs from the Maxwellian equilibrium. These results are relevant in many plasma physics environments, such as the solar wind, where the process of ion-cyclotron heating and the generation of temperature anisotropy and non-Maxwellian velocity distributions are routinely recovered in many in situ measurements, or the laboratory plasmas, where the resonant interaction of ions with ion-cyclotron waves is the primary source of auxiliary heating in the confining apparatus.

Valentini, Francesco [Dipartimento di Fisica and CNISM, Universita di Pisa, Pisa 56127 (Italy); Dipartimento di Fisica and CNISM, Universita della Calabria, Rende (CS) 87036 (Italy); Iazzolino, Antonio; Veltri, Pierluigi [Dipartimento di Fisica and CNISM, Universita della Calabria, Rende (CS) 87036 (Italy)

2010-05-15T23:59:59.000Z

234

Numerical simulation of aerodynamic derivatives and critical wind speed for long-span bridges based on simplified steady wind field  

Science Journals Connector (OSTI)

Combining the computational fluid dynamics-based numerical simulation with the forced vibration technique for extraction ... calculating the aerodynamic derivatives and the critical flutter wind speed for long-sp...

Dabo Xin Ph.D. Student ???; Jinping Ou ???

2007-06-01T23:59:59.000Z

235

Numerical simulation of heat transfer performance of an air-cooled steam condenser in a thermal power plant  

Science Journals Connector (OSTI)

Numerical simulation of the thermal-flow characteristics and heat transfer performance is made of an air-cooled steam condenser (ACSC) in a thermal power plant by considering the effects of ambient wind speed and...

Xiufeng Gao; Chengwei Zhang; Jinjia Wei; Bo Yu

2009-09-01T23:59:59.000Z

236

Numerical simulation of the thermal conditions in a sea bay water area used for water supply to nuclear power plants  

SciTech Connect

Consideration is given to the numerical simulation of the thermal conditions in sea water areas used for both water supply to and dissipation of low-grade heat from a nuclear power plant on the shore of a sea bay.

Sokolov, A. S. [JSC 'B. E. Vedeneev All-Russia Research Institute of Hydraulic Engineering (VNIIG)' (Russian Federation)] [JSC 'B. E. Vedeneev All-Russia Research Institute of Hydraulic Engineering (VNIIG)' (Russian Federation)

2013-07-15T23:59:59.000Z

237

Numerical simulation of propagation of radioactive pollution in the ocean from the Fukushima Dai-ichi nuclear power plant  

Science Journals Connector (OSTI)

Numerical simulation of the large-scale horizontal mixing and transport of radioactive water from the Fukushima Dai-ichi nuclear power plant (NPP) (14102? E, 3727? N, east coast of Honshu Island, Japan) and ...

S. V. Prants; M. Yu. Uleysky; M. V. Budyansky

2011-08-01T23:59:59.000Z

238

Statistically Steady Turbulence in Soap Films: Direct Numerical Simulations with Ekman Friction  

E-Print Network (OSTI)

We present a detailed direct numerical simulation (DNS) designed to investigate the combined effects of walls and Ekman friction on turbulence in forced soap films. We concentrate on the forward-cascade regime and show how to extract the isotropic parts of velocity and vorticity structure functions and thence the ratios of multiscaling exponents. We find that velocity structure functions display simple scaling whereas their vorticity counterparts show multiscaling; and the probability distribution function of the Weiss parameter $\\Lambda$, which distinguishes between regions with centers and saddles, is in quantitative agreement with experiments.

Prasad Perlekar; Rahul Pandit

2008-11-09T23:59:59.000Z

239

Numerical simulation of air/H2 combustion processes in a scramjet turbulent flow  

Science Journals Connector (OSTI)

The aim of this work is to develop a numerical approach, based on the Favre's averaged Navier-Stokes equations coupled with a turbulence model and with a complex finite rate Air/Hydrogen combustion kinetic model to simulate the unsteady axisymetric supersonic hydrogen-air mixing processes. The main application is dedicated to the scramjet hypersonic air-breathing propulsion engine. To achieve this goal the Spalart-Allmaras turbulence model (SA) with correction terms to model the compressibility effects and the complete finite rate chemistry model of Jachimowsky involving 13 species and 153 reactions have been implemented in a finite volume code.

Y. Burtschell; S. Seror; J.D. Parisse; D. Zeitoun

2008-01-01T23:59:59.000Z

240

A review of what numerical simulations tell us about the internal rotation of the sun  

SciTech Connect

The simulated solar differential rotation from two independent numerical modeling efforts agree with each other and with present solar observations. The models solve the nonlinear, three-dimensional, time-dependent, anelastic equations of motion for thermal convection in a stratified, rotating, spherical shell. The simulated angular velocity in the convection zone is constant on cylinders coaxial with the rotation axis, maximum at the equator and decreasing with depth. The latitudinal variation of this angular velocity at the surface is in agreement with Doppler measurements of the solar surface rotation rate. The radial variation through the convection zone is consistent with the analysis of the rotational frequency splitting of solar oscillations. 15 refs., 5 figs.

Glatzmaier, G.A.

1986-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Numerical modelling of solid fuel combustion processes using advanced CFD-based simulation tools  

Science Journals Connector (OSTI)

Computational modelling of combustion processes has been the subject of coninuous research at the Institute of Process Engineering and Power Plant Technology (IVD) over the last two decades. To this end, finite-volume-based computer codes have been developed. In the present paper, some fundamental ideas and approaches of the applied mathematical models and the numerical methods are described, followed by some examples of typical applications of the procedures with special emphasis on the validation of simulation results. These examples show that the application of combustion simulation codes has been extended to comprise a wide range of several different areas ranging from huge bituminous coal-fired utility boilers for electricity production to decentralised small-scale furnaces and tile stove heating inserts for domestic heating.

Uwe Schnell

2001-01-01T23:59:59.000Z

242

Modeling and simulation of the industrial numerical distance relay aimed at knowledge discovery in resident event reporting  

Science Journals Connector (OSTI)

In the motivation of tapping the strong potential of computational intelligence in discovering knowledge of protective relay operations using data mining, modeling and simulation of an actual industrial numerical distance relay and its recording facility ... Keywords: Distance protection, Knowledge Discovery in Databases, Rough Set Theory, association rule, computational intelligence, data mining, numerical protective relay, relay modeling

Mohammad Lutfi Othman, Ishak Aris, Noor Izzri Abdul Wahab

2014-06-01T23:59:59.000Z

243

Numerical simulations of industrial-scale combustion chamber - LES versus RANS  

Science Journals Connector (OSTI)

In this work we focus on the simulation of the process of biomass syngas combustion in the industrial combustion chamber directly linked with gasification chamber, where this gas is continuously producing from the biomass. Conflicting demands from the engineers to have rapid results and hints how to ensure the best conditions for combustion of this particular fuel and to lower the emission of pollutants, with simultaneously deep view inside the process and its stability motivates us to use both the RANS and LES techniques of turbulence modelling, compare it and take their advantages. We designed and performed series of 3D numerical simulations of both cold flow and combustion in complex geometry of industrial burner. It seems to us that the proper approach for modelling of biomass syngas combustion is steady flamelets model. Simulations performed with RANS closure are used as the initialisation of LES models, but their main goal is to predict the long-time oscillation of pressure and temperature observed in the working combustion chamber. On the other hand the main goal of the simulations with LES closure is to predict the proper level of short-time behaviour of the flame and local phenomena.

Kamil Kwiatkowski; Daniel Jasi?ski; Konrad Bajer

2011-01-01T23:59:59.000Z

244

Modelling and simulation of faults in synchronous generators for robust numerical protection  

Science Journals Connector (OSTI)

When an internal fault occurs in a synchronous generator, the symmetry between the parallel paths of the winding is broken and different currents flow in them, due to unsymmetrical magnetic linkage between the stator windings. The aim of this paper is to present a simulation model to investigate the effect of internal fault on the parallel path currents of a large synchronous generator using direct phase quantities. This model is based on a modified winding function approach where the machine inductances are calculated directly from the machine winding distribution using machine electrical parameters instead of the geometrical ones. The simulation results for different cases of internal faults in salient-pole and non-salient-pole synchronous machines have been obtained. Salient-pole synchronous generator has wave winding distribution while the non-salient-pole generator has lap winding arrangement. Due to different stator winding arrangements, the two machines have been simulated individually. By using the simulated fault data, a suitable numerical protection scheme for synchronous generators can be developed.

Amrita Sinha; D.N. Vishwakarma; R.K. Srivastava

2012-01-01T23:59:59.000Z

245

A review on recent advances in the numerical simulation for coalbed-methane-recovery process  

SciTech Connect

The recent advances in numerical simulation for primary coalbed methane (CBM) recovery and enhanced coalbed-methane recovery (ECBMR) processes are reviewed, primarily focusing on the progress that has occurred since the late 1980s. Two major issues regarding the numerical modeling will be discussed in this review: first, multicomponent gas transport in in-situ bulk coal and, second, changes of coal properties during methane (CH{sub 4}) production. For the former issues, a detailed review of more recent advances in modeling gas and water transport within a coal matrix is presented. Further, various factors influencing gas diffusion through the coal matrix will be highlighted as well, such as pore structure, concentration and pressure, and water effects. An ongoing bottleneck for evaluating total mass transport rate is developing a reasonable representation of multiscale pore space that considers coal type and rank. Moreover, few efforts have been concerned with modeling water-flow behavior in the coal matrix and its effects on CH{sub 4} production and on the exchange of carbon dioxide (CO{sub 2}) and CH{sub 4}. As for the second issue, theoretical coupled fluid-flow and geomechanical models have been proposed to describe the evolution of pore structure during CH{sub 4} production, instead of traditional empirical equations. However, there is currently no effective coupled model for engineering applications. Finally, perspectives on developing suitable simulation models for CBM production and for predicting CO{sub 2}-sequestration ECBMR are suggested.

Wei, X.R.; Wang, G.X.; Massarotto, P.; Golding, S.D.; Rudolph, V. [University of Queensland, Brisbane, Qld. (Australia)

2007-12-15T23:59:59.000Z

246

Direct numerical simulation of electrokinetic instability and transition to chaotic motion  

SciTech Connect

A new type of instabilityelectrokinetic instabilityand an unusual transition to chaotic motion near a charge-selective surface (semiselective electric membrane, electrode, or system of micro-/nanochannels) was studied by the numerical integration of the Nernst-Planck-Poisson-Stokes system and a weakly nonlinear analysis near the threshold of instability. A special finite-difference method was used for the space discretization along with a semi-implicit 31/3 -step Runge-Kutta scheme for the integration in time. Two kinds of initial conditions were considered: (a) white-noise initial conditions to mimic room disturbances and subsequent natural evolution of the solution, and (b) an artificial monochromatic ion distribution with a fixed wave number to simulate regular wave patterns. The results were studied from the viewpoint of hydrodynamic stability and bifurcation theory. The threshold of electroconvective movement was found by the linear spectral stability theory, the results of which were confirmed by numerical simulation of the entire system. Our weakly nonlinear analysis and numerical integration of the entire system predict possibility of both kinds of bifurcations at the critical point, supercritical and subcritical, depending on the system parameters. The following regimes, which replace each other as the potential drop between the selective surfaces increases, were obtained: one-dimensional steady solution, two-dimensional steady electroconvective vortices (stationary point in a proper phase space), unsteady vortices aperiodically changing their parameters (homoclinic contour), periodic motion (limit cycle), and chaotic motion. The transition to chaotic motion does not include Hopf bifurcation. The numerical resolution of the thin concentration polarization layer showed spike-like charge profiles along the surface, which could be, depending on the regime, either steady or aperiodically coalescent. The numerical investigation confirmed the experimentally observed absence of regular (near-sinusoidal) oscillations for the overlimiting regimes. There is a qualitative agreement of the experimental and the theoretical values of the threshold of instability, the dominant size of the observed coherent structures, and the experimental and theoretical voltcurrent characteristics.

Demekhin, E. A., E-mail: edemekhi@gmail.com [Laboratory of Micro- and Nanofluidics, Moscow State University, Moscow 119192 (Russian Federation); Department of Computation Mathematics and Computer Science, Kuban State University, Krasnodar 350040 (Russian Federation); Institute of Mechanics, Moscow State University, Moscow 117192 (Russian Federation); Nikitin, N. V. [Institute of Mechanics, Moscow State University, Moscow 117192 (Russian Federation)] [Institute of Mechanics, Moscow State University, Moscow 117192 (Russian Federation); Shelistov, V. S. [Institute of Mechanics, Moscow State University, Moscow 117192 (Russian Federation) [Institute of Mechanics, Moscow State University, Moscow 117192 (Russian Federation); Scientific Research Department, Kuban State University, Krasnodar 350040 (Russian Federation)

2013-12-15T23:59:59.000Z

247

Marine and River Dune Dynamics MARID IV 15 & 16 April 2013 -Bruges, Belgium Numerical simulation of turbulent sediment transport  

E-Print Network (OSTI)

simulation of turbulent sediment transport O. Durán (1,2) , B. Andreotti (1) , P. Claudin (1) 1. Laboratoire Carolina 27515, USA Abstract Sediment transport is studied by means of two phase numerical simulations to empirical transport laws. The vertical velocities of the grains are small and sediment transport occurs

Claudin, Philippe

248

Interpreting Velocities from Heat-Based Flow Sensors by NumericalSimulation  

SciTech Connect

We have carried out numerical simulations of three-dimensional non-isothermal flow around an in situ heat-based flow sensor to investigate how formation heterogeneities can affect the interpretation of ground water flow velocities from this instrument. The flow sensor operates by constant heating of a 0.75 m long, 5 cm diameter cylindrical probe, which contains 30 thermistors in contact with the formation. The temperature evolution at each thermistor can be inverted to obtain an estimate of the ground water flow velocity vector using the standard interpretive method, which assumes that the formation is homogeneous. Analysis of data from heat-based flow sensors installed in a sand aquifer at the Former Fort Ord Army Base near Monterey, California suggested an unexpected component of downward flow. The magnitudes of the vertical velocities were expected to be much less than the horizontal velocities at this site because the sensors were installed just above a clay aquitard. Numerical simulations were conducted to examine how differences in thermal conductivities may lead to spurious indications of vertical flow velocities. We found that a decrease in the thermal conductivity near the bottom of the sensor can perturb the temperature profiles along the instrument in such a manner that analyses assuming homogeneous thermal conductivity could indicate a vertical flow component even though flow is actually horizontal. This work demonstrates how modeling can be used to simulate instrument response to formation heterogeneity, and shows that caution must be used in interpreting data from such devices using overly simplistic assumptions.

Su, Grace W.; Freifeld, Barry M.; Oldenburg, Curtis M.; Jordan,Preston D.; Daley, Paul F.

2005-06-13T23:59:59.000Z

249

Numerical simulations of electrical asymmetry effect on electronegative plasmas in capacitively coupled rf discharge  

SciTech Connect

Recently a so-called electrical asymmetry effect (EAE), which could achieve high-degree separate control of ion flux and energy in dual-frequency capacitively coupled radio-frequency (CCRF) discharges, was discovered theoretically by Heil et al. [J. Phys. D: Appl. Phys. 41, 165202 (2008)] and was confirmed by experiments and theory/numerical simulations later on for electropositive argon discharges. In this work simulations based on particle-in-cell/Monte Carlo collision are performed to study the EAE on electronegative oxygen plasmas in geometrically symmetric CCRF discharges. Dual frequency discharges operating at 13.56 and 27.12 MHz are simulated for different pressures and the results are compared with those of electropositive argon discharges at the same conditions. It is found that in general the EAE on oxygen discharges has similar behavior as on argon discharge: The self-bias voltage {eta} increases monotonically and almost linearly with the increase in the phase angle {theta} between the two driving voltages in the range 0<{theta}<90 deg. , and the maximum ion energy varies by a factor of 3 by adjusting {theta}. However, the ion flux varies with {theta} by {+-}12% for low pressure and by {+-}15% for higher pressure, due primarily to an enhanced plasma series resonance, which then leads to dramatic changes in plasma density, power absorption and consequently the electronegativity. This may place a limitation for achieving separate control of ion energy and flux for electronegative plasma via the EAE.

Zhang Quanzhi; Jiang Wei; Wang Younian [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Hou Lujing [Max Planck Institute for Extraterrestrial Physics, 85748 Garching (Germany)

2011-01-01T23:59:59.000Z

250

Enhanced remedial amendment delivery through fluid viscosity modifications: Experiments and numerical simulations  

Science Journals Connector (OSTI)

Low-permeability zones are typically bypassed when remedial fluids are injected into subsurface heterogeneous aquifer systems. Therefore, contaminants in the bypassed areas may not be contacted by the amendments in the remedial fluid, which may significantly prolong remediation operations. Laboratory experiments and numerical studies have been conducted to investigate the use of a shear-thinning polymer (Xanthan gum) to improve access to low-permeability zones in heterogeneous systems. The chemicals sodium mono-phosphate and the surfactant MA-80 were used as the remedial amendments. The impact of polymer concentration, fluid injection rate, and permeability contrast in the heterogeneous systems has been studied in a series of eleven two-dimensional flow cell experiments. The Subsurface Transport over Multiple Phases (STOMP) simulator was modified to include polymer-induced shear-thinning effects. The experimental and simulation results clearly show that using the polymer leads to an enhanced delivery of remedial amendments to lower-permeability zones and an increased sweeping efficiency. An added benefit of using the polymer is the stabilization of the displacing front when density differences exist between displaced and displacing fluids. The modified STOMP simulator was able to predict the experimental observed fluid displacing behavior well and might be used to predict subsurface remediation performance when a shear-thinning fluid is used to remediate a heterogeneous system at larger scales.

L. Zhong; M. Oostrom; T.W. Wietsma; M.A. Covert

2008-01-01T23:59:59.000Z

251

Numerical simulation of gas flow through unsaturated fractured rock at Yucca Mountain, Nevada  

SciTech Connect

Numerical analysis is used to identify the physical phenomena associated with barometrically driven gas (air and water vapor) flow through unsaturated fractured rock at Yucca Mountain, Nevada. Results from simple finite difference simulations indicate that for a fractured rock scenario, the maximum velocity of air out of an uncased 10 cm borehole is 0.002 m s{sub {minus}1}. An equivalent porous medium (EPM) model was incorporated into a multiphase, multicomponent simulator to test more complex conceptual models. Results indicate that for a typical June day, a diurnal pressure wave propagates about 160 m into the surrounding Tiva Canyon hydrogeologic unit. Dry air that enters the formation evaporates water around the borehole which reduces capillary pressure. Multiphase countercurrent flow develops in the vicinity of the hole; the gas phase flows into the formation while the liquid phase flows toward the borehole. The effect occurs within 0.5 m of the borehole. The amount of water vapor leaving the formation during 1 day is 900 cm{sup 3}. This is less than 0.1% of the total recharge into the formation, suggesting that the barometric effect may be insignificant in drying the unsaturated zone. However, gas phase velocities out of the borehole (3 m s{sup {minus}1}), indicating that observed flow rates from wells along the east flank of Yucca Mountain were able to be simulated with a barometric model.

Cooper, C.A. [Nevada Univ., Las Vegas, NV (United States). Water Resources Center

1990-01-01T23:59:59.000Z

252

Numerical Simulations of Wire and Foil Behaviors under Megaampere Current Drive *  

National Nuclear Security Administration (NNSA)

2: High Energy Density, Plasmas, Magnetic Fields 2: High Energy Density, Plasmas, Magnetic Fields Numerical Simulations of Wire and Foil Electrical Explosion under Helical EMG Current Drive for Warm Dense Matter Generation S.F. Garanin*, A.M. Buyko*, S.D. Kuznetsov*, R.E. Reinovsky† * Russian Federal Nuclear Center - VNIIEF Sarov, 607190, Russia † Los Alamos National Laboratory, Los Alamos, NM 87545 USA Study of properties of Warm Dense Matter (WDM), i. e. substance at densities of the order of that of solids (from 10 % normal density to 2-3 times solid density) and moderate temperatures (1-10 eV), is in recent times an active field of investigations. Experiments to study electrical explosion of thick wires (0.5-2 mm in diameter) driven by currents of about 1 MA were conducted recently [1] on the Zebra facility at the University of Nevada, Reno. The

253

Stability Property of Numerical Cherenkov Radiation and its Application to Relativistic Shock Simulations  

E-Print Network (OSTI)

We studied the stability property of numerical Cherenkov radiation in relativistic plasma flows employing particle-in-cell simulations. Using the implicit finite-difference time-domain method to solve Maxwell equations, we found that nonphysical instability was greatly inhibited with a CFL number of 1.0. The present result contrasts with recently reported results (Vay et al., 2011; Godfrey & Vay,2013) in which magical CFL numbers in the range 0.5-0.7 were obtained with explicit field solvers. In addition, we found employing higher-order shape functions and an optimal implicitness factor further suppressed long-wavelength modes of the instability. The findings allowed the examination of the long-term evolution of a relativistic collisionless shock without the generation of nonphysical wave excitations in the upstream. This achievement will allow us to investigate particle accelerations in relativistic shocks associated with, for example, gamma-ray bursts.

Ikeya, Naoki

2014-01-01T23:59:59.000Z

254

Numerical simulations of interfacial debonding in ductile-phase reinforced intermetallic matrix composites  

SciTech Connect

The fracture toughness of brittle intermetallic compounds can be improved by ductile-phase reinforcements. Effectiveness of the ductile phase in bridging cracks, and therefore increasing, the composite toughness, is known qualitatively to depend upon the extent of debonding, between the two phases. Numerical crack-growth simulations are used here to provide semi-quantitative predictions of the influence of interfacial debonding on the macroscopic stress-displacement behavior and, hence, the fracture toughness of an idealized Pb/glass composite. The interfacial toughness required to cause debonding, characterized by a constant critical energy release rate, is varied parametrically. As expected, higher interfacial toughness results in less interphase debonding, higher composite strength, and greater ductile-phase constraint. Consequently, the increase in ductile-phase triaxiality can potentially accelerate internal void formation and growth or facilitate cleavage fracture, either of which would likely decrease the toughness of the composite.

Henshall, G.A.; Zywicz, E.; Strum, M.J.

1993-08-10T23:59:59.000Z

255

Numerical simulation of narrow bipolar electromagnetic pulses generated by thunderstorm discharges  

SciTech Connect

Using the concept of avalanche relativistic runaway electrons (REs), we perform numerical simulations of compact intracloud discharge (CID) as a generator of powerful natural electromagnetic pulses (EMPs) in the HF-VHF range, called narrow bipolar pulses (NBPs). For several values of the field overvoltage and altitude at which the discharge develops, the numbers of seed electrons initiating the avalanche are evaluated, with which the calculated EMP characteristics are consistent with the measured NBP parameters. We note shortcomings in the hypothesis assuming participation of cosmic ray air showers in avalanche initiation. The discharge capable of generating NBPs produces REs in numbers close to those in the source of terrestrial {gamma}-ray flashes (TGFs), which can be an argument in favor of a unified NBP and TGF source.

Bochkov, E. I.; Babich, L. P., E-mail: babich@elph.vniief.ru; Kutsyk, I. M. [All-Russia Research Institute of Experimental Physics, Russian Federal Nuclear Center (Russian Federation)] [All-Russia Research Institute of Experimental Physics, Russian Federal Nuclear Center (Russian Federation)

2013-07-15T23:59:59.000Z

256

The Origin and Kinematics of Cold Gas in Galactic Winds: Insight from Numerical Simulations  

E-Print Network (OSTI)

We study the origin of Na I absorbing gas in ultraluminous infrared galaxies motivated by the recent observations by Martin of extremely superthermal linewidths in this cool gas. We model the effects of repeated supernova explosions driving supershells in the central regions of molecular disks with M_d=10^10 M_\\sun, using cylindrically symmetric gas dynamical simulations run with ZEUS-3D. The shocked swept-up shells quickly cool and fragment by Rayleigh-Taylor instability as they accelerate out of the dense, stratified disks. The numerical resolution of the cooling and compression at the shock fronts determines the peak shell density, and so the speed of Rayleigh-Taylor fragmentation. We identify cooled shells and shell fragments as Na I absorbing gas and study its kinematics. We find that simulations with a numerical resolution of \\le 0.2 pc produce multiple Rayleigh-Taylor fragmented shells in a given line of sight. We suggest that the observed wide Na I absorption lines, = 320 \\pm 120 km s^-1 are produced by these multiple fragmented shells traveling at different velocities. We also suggest that some shell fragments can be accelerated above the observed average terminal velocity of 750 km s^-1 by the same energy-driven wind with an instantaneous starburst of \\sim 10^9 M_\\sun. The bulk of mass is traveling with the observed average shell velocity 330 \\pm 100 km s^-1. Our results show that an energy-driven bubble causing Rayleigh-Taylor instabilities can explain the kinematics of cool gas seen in the Na I observations without invoking additional physics relying primarily on momentum conservation, such as entrainment of gas by Kelvin-Helmholtz instabilities, ram pressure driving of cold clouds by a hot wind, or radiation pressure acting on dust. (abridged)

Akimi Fujita; Crystal L. Martin; Mordecai-Mark Mac Low; Kimberly C. B. New; Robert Weaver

2008-03-19T23:59:59.000Z

257

Numerical simulation of a viscous vortex ring interaction with a density interface  

SciTech Connect

When a vortex-dominated flow interacts with a sharp density interface, the dynamics are characterized by the interaction of baroclinically generated vorticity with the already existing vorticity field. This can be seen in many natural and technology settings; examples are the interaction of a ship or submarine wake with a thermocline, the collision of a buoyant thermal with a temperature inversion, and the interaction of a vortex flow with a flame front. This problem also serves as a generic model for turbulent mixing and entrainment processes across sharp density interfaces. The interaction between vortices and a free surface, with corresponds to the case where the density jump is very large, has been studied fairly extensively, both experimentally and computationally. By comparison, the literature for the more general case of vortex pairs and rings interacting with sharp density interfaces is relatively sparse. Experiments and numerical studies have been performed, but the numerical simulations were confined primarily to vortex pairs, restricted to the inviscid case, and the effect of density variation modeled under the Boussinesq approximation. The experiments were also confined to the Boussinesq regime. In this paper, we study the motion of a vortex ring in a sharply stratified, viscous fluid via a numerical solution of the full Navier-Stokes equations with finite-amplitude density variation. both Boussinesq and non-Boussinesq flow regimes will be studied, the effect of viscosity on the interaction will be examined, and three-dimensional aspects of the motion will be addressed, such as Widnall instability of the vortex ring and vortex reconnection at the interface.

Marcus, D.L.; Bell, J.B.

1990-10-01T23:59:59.000Z

258

Numerical simulation of a Q-switched cw chemical HF laser  

SciTech Connect

A mathematical model of a Q-switched cw chemical laser is developed. The model is based on a simplified description of the active medium and the exact wave description of the mode structure of radiation. The model is used to study numerically the spatial-angular parameters of the output beam of a HF laser. We considered an unstable cavity that provided a high stability of the axis of the laser-pulse radiation pattern upon Q-switching with the help of a rotating mirror. The results of numerical simulation showed that for typical dimensions of a plane or an unstable cavity of the positive branch in a cw chemical laser, the angular radiation divergence rapidly changes in time and on average exceeds the diffraction limit by an order of magnitude. The problem can be solved by replacing a rotating mirror Q switch by a fixed one with time-dependent transmission. We also considered a negative-branch unstable cavity which can provide a stable radiation divergence upon Q-switching produced by a rotating mirror. (lasers)

Kuprenyuk, V I [Institute for Laser Physics, Federal State Unitary Enterprise ' Scientific and Industrial Corporation 'Vavilov State Optical Institute', St. Petersburg (Russian Federation); Maksimov, Yurii P; Mashendzhinov, Viktor I; Rotinyan, Mikhail A; Fedorov, Igor' A [Russian Science Centre 'Applied Chemistry', St Petersburg (Russian Federation); Rodionov, A Yu

2007-03-31T23:59:59.000Z

259

Numerical simulation of wind effects on a stand-alone ground mounted photovoltaic (PV) system  

Science Journals Connector (OSTI)

Abstract 3D Reynolds-Averaged Navier-Stokes (RANS) simulations using an unsteady solver with steady inlet conditions are carried out to investigate the wind load and flow field around a ground mounted stand-alone photovoltaic (PV) system with 25 panel tilt angle immersed in the atmospheric boundary layer (ABL) using the shear stress transport (SST) k-? turbulence closure. Wind directions of the incoming flow are varied from 0 to 180 at 45 intervals. Mean pressure coefficients on the surfaces of the PV panel are compared with the wind tunnel measurement by Abiola-Ogedengbe (2013) and an agreement within 46% is found. Coefficients of drag, lift and overturning moment for the PV system are computed from the numerical simulations. In terms of maximum uplift, 180 is found to be the critical wind direction whereas in terms of overturning moments, 45 and 135 are the critical wind directions. The wind velocity and vorticity fields around the panel are correlated and analyzed with respect to the pressure distribution on the panel surfaces.

Chowdhury Mohammad Jubayer; Horia Hangan

2014-01-01T23:59:59.000Z

260

A Review of Direct Numerical Simulations of Astrophysical Detonations and Their Implications  

SciTech Connect

Multi-dimensional direct numerical simulations (DNS) of astrophysical detonations in degenerate matter have revealed that the nuclear burning is typically characterized by cellular structure caused by transverse instabilities in the detonation front. Type Ia supernova modelers often use one- dimensional DNS of detonations as inputs or constraints for their whole star simulations. While these one-dimensional studies are useful tools, the true nature of the detonation is multi-dimensional. The multi-dimensional structure of the burning influences the speed, stability, and the composition of the detonation and its burning products, and therefore, could have an impact on the spectra of Type Ia supernovae. Considerable effort has been expended modeling Type Ia supernovae at densities above 1 107 g cm 3 where the complexities of turbulent burning dominate the flame propagation. However, most full star models turn the nuclear burning schemes off when the density falls below 1 107 g cm 3 and distributed burning begins. The deflagration to detonation transition (DDT) is believed to occur at just these densities and consequently they are the densities important for studying the properties of the subsequent detonation. This work will review the status of DNS studies of detonations and their possible implications for Type Ia supernova models. It will cover the development of Detonation theory from the first simple Chapman-Jouguet (CJ) detonation models to the current models based on the time-dependent, compressible, reactive flow Euler equations of fluid dynamics.

Parete-Koon, Suzanne T [ORNL; Messer, Bronson [ORNL; Smith, Chris R [ORNL; Papatheodore, Thomas L [ORNL

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Numerical simulation on the influence of water spray in thermal plasma treatment of CF4 gas  

Science Journals Connector (OSTI)

Nitrogen thermal plasma generated by a non-transferred DC arc plasma torch was used to decompose tetrafluoromethane (CF4). In the thermal decomposition process, water was used as a chemical reactant source. Two kinds of water spray methods were compared: water spray directly to the arc plasma flame and indirectly to the reactor tube wall. Although the same operating conditions of input power, waste gas, and sprayed water flow rate were employed for each water spray methods, a relatively higher decomposition rate was achieved in the case of water spray to the reactor wall. In order to investigate the effects of water spraying direction on the thermal decomposition process, a numerical simulation on the thermal plasma flow characteristics was carried out considering water injection in the reactor. The simulation was performed using commercial fluid dynamics software of the FLUENT, which is suitable for calculating a complex flow. From the results, it was revealed that water spray to the reactor wall and use of a relatively small quantity of water are more effective methods for decomposition of CF4, because a sufficiently high temperature area and long reaction time can be maintained over large area.

Tae-Hee Kim; Sooseok Choi; Dong-Wha Park

2012-01-01T23:59:59.000Z

262

Numerical-simulation and experimental-validation of the largest Egyptian solar process-heat system  

Science Journals Connector (OSTI)

El-Nasr pharmaceutical solar process heat project is considered as the largest industrial system installed and working in east Cairo Egypt 30N. It was simply constructed from a one-axis tracking parabolic-trough collector that can produce about 1.3 ton/h saturated steam to feed the industrial processes in the company. Twenty-three bar compressed water is heated inside 1958.4 m2 collectors and later on it is flashed in a steam flash-drum to produce saturated steam at 8 bars and 175 C that is fed to the process heat. A mathematical model was developed for the system components to simulate annual performance of the system. The simulation results were verified successfully by the measured data that are monitoring the system performance. First each component of the mathematical model was experimentally validated separately. Accordingly the whole mathematical model was validated under different weather conditions along the year. The validated numerical model was optimized. The optimal number of collectors connected in series was obtained as three collectors not 36 as installed. An economical study of the installed system was provided. The optimal design of the system was economically estimated. The optimal collector area is less than that installed it equals about 538 m2. Annual performance of the system is presented indicating the seasonal variation. It was found that the optimized system can produce about 2 ton/h in average. Moreover that value is more than that was proposed by the system design.

Adel M. Abdel-Dayem

2011-01-01T23:59:59.000Z

263

THREE-DIMENSIONAL NUMERICAL SIMULATIONS OF FAST-TO-ALFVEN CONVERSION IN SUNSPOTS  

SciTech Connect

The conversion of fast waves to the Alfven mode in a realistic sunspot atmosphere is studied through three-dimensional numerical simulations. An upward propagating fast acoustic wave is excited in the high-{beta} region of the model. The new wave modes generated at the conversion layer are analyzed from the projections of the velocity and magnetic field in their characteristic directions, and the computation of their wave energy and fluxes. The analysis reveals that the maximum efficiency of the conversion to the slow mode is obtained for inclinations of 25 Degree-Sign and low azimuths, while the Alfven wave conversions peak at high inclinations and azimuths between 50 Degree-Sign and 120 Degree-Sign . Downward propagating Alfven waves appear at the regions of the sunspot where the orientation of the magnetic field is in the direction opposite to the wave propagation, since at these locations the Alfven wave couples better with the downgoing fast magnetic wave which is reflected due to the gradients of the Alfven speed. The simulations show that the Alfven energy at the chromosphere is comparable to the acoustic energy of the slow mode, being even higher at high inclined magnetic fields.

Felipe, T., E-mail: tobias@cora.nwra.com [NorthWest Research Associates, Colorado Research Associates, Boulder, CO 80301 (United States)

2012-10-20T23:59:59.000Z

264

Equation of State and Constitutive Models for Numerical Simulations of Dust Impacts on the Solar Probe  

E-Print Network (OSTI)

This report presents new EOS and strength models for use in numerical hydrocode simulations of dust impacts on the NASA solar probe space vehicle. This spacecraft will be subjected to impact at velocities up to 300 km/s, producing pressures as high as 100 TPa and temperatures as high as 200 eV. Hence the material models must treat a variety of physical and chemical phenomena, including solid-solid transitions, melting and vaporization, chemical reactions, electronic excitation and ionization. The EOSPro code is used to develop tabular EOS that include these effects. The report discusses the theoretical methods used to create the new EOS tables and constitutive models for six materials--Al2O3, two porous carbon materials, fused SiO2, a silicone elastomer, and germanium--which will be used in the thermal protection shield (TPS) and solar cells, the components most vulnerable to dust impacts. It also presents the results of hydrocode simulations of dust impacts on the TPS and on glass targets. It discusses the i...

Kerley, Gerald I

2013-01-01T23:59:59.000Z

265

Numerical simulation of dilute and dense layered coal-dust explosions  

Science Journals Connector (OSTI)

Abstract Multidimensional time-dependent simulations were performed to study the interaction of a shock wave and resulting shear layer with layers of coal dust. The simulations used a high-order compressible numerical method for fluid dynamics and included a Eulerian kinetic-theory-based granular multiphase model applicable over a range from dense to dilute particle volume fractions. Two cases were considered: a loose dust layer with an initial volume fraction of 1%, and a dense dust layer with an initial volume fraction of 47%. For both cases, the final result is a coupled complex consisting of a shock leading a coal-dust flame. In the simulations presented here, a shock is initially produced from remnants of a natural gas detonation, which has decayed into a shock once it passes into a region containing no gaseous fuel. This shock weakens further due to mechanical and thermal losses from lifting and entraining the coal dust. The lifted dust subsequently ignites in the shock-heated air and produces a structure similar to a mixing-limited, nonpremixed flame. The flame consists of a burning coal dust wave that follows the shock. The distance between the shock and ignition point is determined by the induction length of carbon char, which is ? 170cm and ? 15cm for the 47% and 1% cases, respectively. The burning of coal particles is predominantly from heterogeneous reactions with carbon char, and volatilized methane combustion is a secondary effect. Air and particles are mixed by relative velocity between the gas and solid phases. Coal particles burn and produce pressure waves that accelerate the shock from Mach 2.2 to 2.6 for the dilute layer, and from Mach 1.7 to 1.8 in the dense layer.

Ryan W. Houim; Elaine S. Oran

2014-01-01T23:59:59.000Z

266

TOUGH2: A general-purpose numerical simulator for multiphase nonisothermal flows  

SciTech Connect

Numerical simulators for multiphase fluid and heat flows in permeable media have been under development at Lawrence Berkeley Laboratory for more than 10 yr. Real geofluids contain noncondensible gases and dissolved solids in addition to water, and the desire to model such `compositional` systems led to the development of a flexible multicomponent, multiphase simulation architecture known as MULKOM. The design of MULKOM was based on the recognition that the mass-and energy-balance equations for multiphase fluid and heat flows in multicomponent systems have the same mathematical form, regardless of the number and nature of fluid components and phases present. Application of MULKOM to different fluid mixtures, such as water and air, or water, oil, and gas, is possible by means of appropriate `equation-of-state` (EOS) modules, which provide all thermophysical and transport parameters of the fluid mixture and the permeable medium as a function of a suitable set of primary thermodynamic variables. Investigations of thermal and hydrologic effects from emplacement of heat-generating nuclear wastes into partially water-saturated formations prompted the development and release of a specialized version of MULKOM for nonisothermal flow of water and air, named TOUGH. TOUGH is an acronym for `transport of unsaturated groundwater and heat` and is also an allusion to the tuff formations at Yucca Mountain, Nevada. The TOUGH2 code is intended to supersede TOUGH. It offers all the capabilities of TOUGH and includes a considerably more general subset of MULKOM modules with added capabilities. The paper briefly describes the simulation methodology and user features.

Pruess, K. [Lawrence Berkeley Lab., CA (United States)

1991-06-01T23:59:59.000Z

267

Numerical and simulation study of terahertz radiation generation by laser pulses propagating in the extraordinary mode in magnetized plasma  

SciTech Connect

A one-dimensional numerical model for studying terahertz radiation generation by intense laser pulses propagating, in the extraordinary mode, through magnetized plasma has been presented. The direction of the static external magnetic field is perpendicular to the polarization as well as propagation direction of the laser pulse. A transverse electromagnetic wave with frequency in the terahertz range is generated due to the presence of the magnetic field. Further, two-dimensional simulations using XOOPIC code show that the THz fields generated in plasma are transmitted into vacuum. The fields obtained via simulation study are found to be compatible with those obtained from the numerical model.

Jha, Pallavi; Kumar Verma, Nirmal [Department of Physics, University of Lucknow, Lucknow-226007 (India)

2014-06-15T23:59:59.000Z

268

Simulation of fluid displacement in porous media - improved methods to minimize numerical dispersion and grid orientation effects  

E-Print Network (OSTI)

in performance. Also, under these conditions, the calculated results are highly sen- sitive to grid orientation. '1 * Todd, et al. demonstrated the grid orientation effects for five-point finite difference reservoir simulators. They proposed a two... GRAPHICAL DESCRIPTION numerical dispersion and grid orientation effects. The difference in recovery performance for diagonal and parallel grids was not ap- preciable when finer grids were used, Coats, et al. simulated a five-spot steamflood...

Laprea-Bigott, Marcelo

1976-01-01T23:59:59.000Z

269

Supercritical CO2 core flooding and imbibition in Berea sandstone CT imaging and numerical simulation  

Science Journals Connector (OSTI)

This paper reports a numerical simulation study of a full CO2 core flooding and imbibition cycle on a Berea sandstone core (measured 14.45cm long and 3.67cm in diameter). During the test, supercritical CO2 (at 10MPa and 40C) and CO2-saturated brine was injected into one end of the horizontal core and a X-ray CT scanner (with a resolution of 0.35mmנ0.35mm) was employed to monitor and record changes in the fluid saturations, which enabled 3D mapping of the saturation profiles throughout the core during the course of core flooding test. From the digital CT saturation data, mean saturation profiles along the core length were plotted with time. A 1D model of the core was constructed to simulate the core flooding test and attempt was made to history match core test results, particularly the evolution of the mean CO2 saturation profiles during CO2 injection. Curve-fitting of the centrifugal air-water capillary pressure data (drainage) for the Berea core showed that the core test data could be adequately described by the Van Genuchten equation. The matched set of parameters ( S l r , P 0 , m ) were 0.09, 20KPa, 0.425 respectively. In the absence of the relative permeability for the Berea core, it was decided to use the parameters obtained from matching the air-water capillary pressure data as a first approximation for the CO2-brine system in the model.

Ji-Quan Shi; Ziqiu Xue; Sevket Durucan

2011-01-01T23:59:59.000Z

270

Numerical Simulation of Two-Phase Flow in Severely Damaged Core Geometries  

SciTech Connect

In the event of a severe accident in a nuclear reactor, the oxidation, dissolution and collapse of fuel rods is likely to change dramatically the geometry of the core. A large part of the core would be damaged and would look like porous medium made of randomly distributed pellet fragments, broken claddings and relocated melts. Such a complex medium must be cooled in order to stop the accident progression. IRSN investigates the effectiveness of the water re-flooding mechanism in cooling this medium where complex two-phase flows are likely to exist. A macroscopic model for the prediction of the cooling sequence was developed for the ICARE/CATHARE code (IRSN mechanistic code for severe accidents). It still needs to be improved and assessed. It appears that a better understanding of the flow at the pore scale is necessary. As a result, a direct numerical simulation (DNS) code was developed to investigate the local features of a two-phase flow in complex geometries. In this paper, the Cahn-Hilliard model is used to simulate flows of two immiscible fluids in geometries representing a damaged core. These geometries are synthesized from experimental tomography images (PHEBUS-FP project) in order to study the effects of each degradation feature, such as displacement and fragmentation of the fuel rods and claddings, on the two-phase flow. For example, the presence of fragmented fuel claddings is likely to enhance the trapping of the residual phase (either steam or water) within the medium which leads to less flow fluctuations in the other phase. Such features are clearly shown by DNS calculations. From a series of calculations where the geometry of the porous medium is changed, conclusions are drawn for the impact of rods damage level on the characteristics of two-phase flow in the core. (authors)

Meekunnasombat, Phongsan; Fichot, Florian [Institute of Radioprotection and Nuclear Safety - IRSN, BP 17 - 92262 Fontenay-aux-Roses Cedex 31, avenue de la Division Leclerc 92260 Fontenay-aux-Roses (France); Quintard, Michel [Institut de Mecanique des Fluides de Toulouse, 1 Allee du Professeur Camille Soula, 31400 Toulouse (France)

2006-07-01T23:59:59.000Z

271

Numerical simulation of the dispersion of contaminants by a characteristic-based method with applications to the  

E-Print Network (OSTI)

of the thermal outflow of some power plants in the Huelva estuary was studied. The outline of the paper developed are presented: the dispersion of the plume of the Ebro river and the thermal outflow of powerNumerical simulation of the dispersion of contaminants by a characteristic-based method

Politècnica de Catalunya, Universitat

272

Mathematical analysis and numerical simulation of multi-phase multi-component flow in heterogeneous porous media  

E-Print Network (OSTI)

where is the rock porosity, S and are the saturation (fluid volume fraction) and density of phase is the permeability (a tensor) of the rock, k is the relative permeability, is the viscosity, p the pressure in phase 2012 Accepted 10 January 2012 Available online 24 January 2012 Keywords: Reservoir simulation Numerical

Cirpka, Olaf Arie

273

Numerical simulation of bubble and droplet deformation by a level set approach with surface tension in three dimensions  

E-Print Network (OSTI)

Numerical simulation of bubble and droplet deformation by a level set approach with surface tension-dimensional Navier­Stokes solver for incompressible two-phase flow problems with surface tension and apply is the impact of surface tension and its discretization on the overall convergence behavior and conservation

Sminchisescu, Cristian

274

Introduction Flattening the Earth Continuation procedure Flat Earth Numerical simulations Continuation from a flat to a round Earth model  

E-Print Network (OSTI)

Introduction Flattening the Earth Continuation procedure Flat Earth Numerical simulations Continuation from a flat to a round Earth model in the coplanar orbit transfer problem M. Cerf1, T. Haberkorn, SADCO 2011, March 2nd M. Cerf, T. Haberkorn, E. Tr´elat Continuation from a flat to a round Earth model

Boyer, Edmond

275

Multi-harmonic measurements and numerical simulations of nonlinear vibrations of a beam with non-ideal boundary  

E-Print Network (OSTI)

Multi-harmonic measurements and numerical simulations of nonlinear vibrations of a beam with non This study presents a direct comparison of measured and predicted nonlinear vibrations of a clamped with measurements is performed in the vicinity of the primary resonance. First of all, a nonlinear analytical model

Boyer, Edmond

276

ABSTRACT FINAL ID: SH51A-1991 TITLE: Three-Dimensional Numerical Simulations of Interaction Between Flux Ropes in the  

E-Print Network (OSTI)

ABSTRACT FINAL ID: SH51A-1991 TITLE: Three-Dimensional Numerical Simulations of Interaction Between, United States. Title of Team: ABSTRACT BODY: We have recently identified in three-dimensional (3D implications in the generation of Alfven waves and MHD turbulence. This work is supported by a NASA grant NNX08

Ng, Chung-Sang

277

Evaluation and Numerical Simulation of Tsunami for Coastal Nuclear Power Plants of India  

SciTech Connect

Recent tsunami generated on December 26, 2004 due to Sumatra earthquake of magnitude 9.3 resulted in inundation at the various coastal sites of India. The site selection and design of Indian nuclear power plants demand the evaluation of run up and the structural barriers for the coastal plants: Besides it is also desirable to evaluate the early warning system for tsunami-genic earthquakes. The tsunamis originate from submarine faults, underwater volcanic activities, sub-aerial landslides impinging on the sea and submarine landslides. In case of a submarine earthquake-induced tsunami the wave is generated in the fluid domain due to displacement of the seabed. There are three phases of tsunami: generation, propagation, and run-up. Reactor Safety Division (RSD) of Bhabha Atomic Research Centre (BARC), Trombay has initiated computational simulation for all the three phases of tsunami source generation, its propagation and finally run up evaluation for the protection of public life, property and various industrial infrastructures located on the coastal regions of India. These studies could be effectively utilized for design and implementation of early warning system for coastal region of the country apart from catering to the needs of Indian nuclear installations. This paper presents some results of tsunami waves based on different analytical/numerical approaches with shallow water wave theory. (authors)

Sharma, Pavan K.; Singh, R.K.; Ghosh, A.K.; Kushwaha, H.S. [Bhabha Atomic Research Centre-Trombay, Mumbai 400 085 (India)

2006-07-01T23:59:59.000Z

278

Finite-rate chemistry and transient effects in direct numerical simulations of turbulent nonpremixed flames  

SciTech Connect

Three-dimensional direct numerical simulations (DNS) of turbulent nonpremixed flames including finite-rate chemistry and heat release effects were performed. Two chemical reaction models were considered: (1) a single-step global reaction model in which the heat release and activation energy parameters are typical combustion applications, and (2) a two-step reaction model to stimulate radical production and consumption and to compare against the single-step model. The model problem consists of the interaction between an initially unstained laminar diffusion flame and a three-dimensional field of homogeneous turbulence. Conditions ranging from fast chemistry to the pure mixing limit were studied by varying a global Damkoehler number. Results suggest that turbulence-induced mixing acting along the stoichiometric line leads to a strong modification of the inner structure of the turbulent flame compared with a laminar strained flame, resulting in intermediate species concentrations well above the laminar prediction. This result is consistent the experimental observations. Comparison of the response of the turbulent flame structure due to changes in the scalar dissipation rate with a steady strained laminar flame reveals that unsteady strain rates experienced by the turbulent flame may be responsible for h3e observed high concentrations of reaction intermediates.

Mahalingam, S. [Univ. of Colorado, Boulder, CO (United States). Center for Combustion Research] [Univ. of Colorado, Boulder, CO (United States). Center for Combustion Research; Chen, J.H. [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility] [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility; Vervisch, L. [CORIA, Rouen (France). Laboratoire de Mechanique des Fluides Numeriques] [CORIA, Rouen (France). Laboratoire de Mechanique des Fluides Numeriques

1995-08-01T23:59:59.000Z

279

Direct numerical simulations of type Ia supernovae flames I: The landau-darrieus instability  

SciTech Connect

Planar flames are intrinsically unstable in open domains due to the thermal expansion across the burning front--the Landau-Darrieus instability. This instability leads to wrinkling and growth of the flame surface, and corresponding acceleration of the flame, until it is stabilized by cusp formation. We look at the Landau-Darrieus in stability for C/O thermonuclear flames at conditions relevant to the late stages of a Type Ia supernova explosion. Two-dimensional direct numerical simulations of both single-mode and multi-mode perturbations using a low Mach number hydrodynamics code are presented. We show the effect of the instability on the flame speed as a function of both the density and domain size, demonstrate the existence of the small scale cutoff to the growth of the instability, and look for the proposed breakdown of the non-linear stabilization at low densities. The effects of curvature on the flame as quantified through measurements of the growth rate and computation of the corresponding Markstein number. While accelerations of a few percent are observed, they are too small to have any direct outcome on the supernova explosion.

Bell, J.B.; Day, M.S.; Rendleman, C.A.; Woosley, S.E.; Zingale, M.

2003-11-24T23:59:59.000Z

280

Detailed numerical simulation of syngas combustion under partially premixed combustion engine conditions  

Science Journals Connector (OSTI)

Two-dimensional detailed numerical simulation is performed to study syngas/air combustion under partially premixed combustion (PPC) engine conditions. Detailed chemical kinetics and transport properties are employed in the study. The fuel, a mixture of CO and H2 with a 1:1molar ratio, is introduced to the domain at two different instances of time, corresponding to the multiple injection strategy of fuel used in PPC engines. It is found that the ratio of the fuel mass between the second injection and the first injection affects the combustion and emission process greatly; there is a tradeoff between NO emission and CO emission when varying the fuel mass ratio. The ignition zone structures under various fuel mass ratios are examined. A premixed burn region and a diffusion burn region are identified. The premixed burn region ignites first, followed by the ignition of mixtures at the diffusion burn region, and finally a thin diffusion flame is formed to burn out the remaining fuel. NO is produced mainly in the premixed burn region, and later from the diffusion burn region in mixtures close to stoichiometry, whereas unburned CO emission is mainly from the diffusion burn region. An optimization of the fuel mass in the two regions can offer a better tradeoff between NO emission and CO emission. The effects of initial temperature and turbulence on the premixed burn and diffusion burn regions are investigated.

F. Zhang; R. Yu; X.S. Bai

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Physical mechanism and numerical simulation of the inception of the lightning upward leader  

SciTech Connect

The upward leader is a key physical process of the leader progression model of lightning shielding. The inception mechanism and criterion of the upward leader need further understanding and clarification. Based on leader discharge theory, this paper proposes the critical electric field intensity of the stable upward leader (CEFISUL) and characterizes it by the valve electric field intensity on the conductor surface, E{sub L}, which is the basis of a new inception criterion for the upward leader. Through numerical simulation under various physical conditions, we verified that E{sub L} is mainly related to the conductor radius, and data fitting yields the mathematical expression of E{sub L}. We further establish a computational model for lightning shielding performance of the transmission lines based on the proposed CEFISUL criterion, which reproduces the shielding failure rate of typical UHV transmission lines. The model-based calculation results agree well with the statistical data from on-site operations, which show the effectiveness and validity of the CEFISUL criterion.

Li Qingmin [Beijing Key Lab of High Voltage and EMC, School of Electric and Electronic Engineering, North China Electric Power University, Beijing 102206 (China) and State Key Lab of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206 (China); Lu Xinchang; Shi Wei; Zhang Li; Zou Liang; Lou Jie [Shandong Provincial Key Lab of UHV Technology and Gas Discharge, School of Electrical Engineering, Shandong University, Jinan 250061 (China)

2012-12-15T23:59:59.000Z

282

Numerical simulation of airflow in a solar chimney for cooling buildings in the city of Yazd  

Science Journals Connector (OSTI)

This paper investigates numerically a two-dimensional turbulent flow in a solar chimney due to free convectionheat transfer. For evaluation of the fluid flow and heat transfer in the system the basic equations including conservation of mass and momentum in the x y directions and energy in the Cartesian coordinate are converted to the algebraic form using the finite volume method. This simulation (use the commercial CFD code) provides the profile of temperature velocity and mass flow rate variations in the solar chimney in different conditions. These results can be used to evaluate the effective parameters and optimize the performance of the system for natural evaporative cooling and ventilating the buildings. Based on climate conditions in Yazd the optimum dimension of the width of the chimney is 0.30.4?m inlet height is 0.3?m and the flow rate created in the system and at the outlet is at 0.18 m3/s. The mean cooling rate resulted from the solar chimney is about 800?W/m2. Considering the long hot and sunny days of summer (about 12?h in Yazd) the use of this system in warm and dry region is recommended. We can save a considerable amount of energy sources such as natural gas or oil and lower CO2 emissions.

Vali Kalantar

2012-01-01T23:59:59.000Z

283

Intercomparison of numerical simulation codes for geologic disposal of CO2  

E-Print Network (OSTI)

Study for Enhanced Coalbed Methane Recovery Processes, Partcapabilities are available. Coalbed methane simulators are

2002-01-01T23:59:59.000Z

284

Course MA59800: Numerical Simulation in Applied Geophysics. From the Mesoscale to the Macroscale.  

E-Print Network (OSTI)

Description Wave propagation is a common technique used in hydrocarbon exploration geophysics, mining and reservoir characterization and production, among other fields. Local variations in the fluid and solid gradients via a slow-wave diffusion process that can be analyzed using numerical experiments. Numerical rock

Santos, Juan

285

E-Print Network 3.0 - assessment numerical simulation Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

and Application Analysis Summary: design, software tuning Hardware :: Cycle-accurate simulation Software :: Execution-based profiling... Overview Hierarchical Clustering ::...

286

Numerical Simulation of Combustion Processes in Homogeneous and Stratified Charge Spark Ignition Engines  

Science Journals Connector (OSTI)

A three-dimensional simulation technique for stratified combustion process in direct injection gasoline engines is developed....

Hiroshi Miyagawa; Yoshihiro Nomura; Makoto Koike

2001-01-01T23:59:59.000Z

287

Physical modeling and numerical simulation of subcooled boiling in one- and three-dimensional representation of bundle geometry  

SciTech Connect

Numerical simulation of subcooled boiling in one-dimensional geometry with the Homogeneous Equilibrium Model (HEM) may yield difficulties related to the very low sonic velocity associated with the HEM. These difficulties do not arise with subcritical flow. Possible solutions of the problem include introducing a relaxation of the vapor production rate. Three-dimensional simulations of subcooled boiling in bundle geometry typical of fast reactors can be performed by using two systems of conservation equations, one for the HEM and the other for a Separated Phases Model (SPM), with a smooth transition between the two models.

Bottoni, M.; Lyczkowski, R.; Ahuja, S.

1995-07-01T23:59:59.000Z

288

Development of a Two-Fluid Drag Law for Clustered Particles Using Direct Numerical Simulation and Validation through Experiments  

NLE Websites -- All DOE Office Websites (Extended Search)

Two-Fluid Drag Law Two-Fluid Drag Law for Clustered Particles Using Direct Numerical Simulation and Validation through Experiments Background The Historically Black Colleges and Universities and Other Minority Institutions (HBCU/ OMI) Research and Development (R&D) Program within the U. S. Department of Energy (DOE) Office of Fossil Energy (FE) provides a mechanism for cooperative FE R&D projects between DOE and the HBCU/OMI community. This program encourages

289

INEX (integrated numerical experiment) simulations of the Los Alamos HIBAF (high-brightness accelerator free-electron laser) free-electron laser MOPA (master oscillator power amplifier) experiment  

SciTech Connect

We present results of Integrated Numerical Experiment (INEX) simulations of the performance of a 1-m untapered wiggler FEL oscillator driving a 2-m wiggler FEL amplifier for the new HIBAF (High-Brightness Accelerator Free-Electron Laser) facility at Los Alamos. INEX simulations utilize a numerically-generated electron micropulse, from ISIS/PARMELA calculations of the photoinjector/linac/beam transport system, in the 3-D FEL simulation code FELEX. 13 refs., 10 figs., 1 tab.

Goldstein, J.C.; Carlsten, B.E.; McVey, B.D.

1989-01-01T23:59:59.000Z

290

Numerical simulation of micro/mini-channel based methane-steam reformer.  

E-Print Network (OSTI)

??Numerical modeling of methane-steam reforming is performed in a micro/mini-channel with heat input through catalytic channel walls. The low-Mach number, variable density Navier-Stokes equations together (more)

Peterson, Daniel Alan

2010-01-01T23:59:59.000Z

291

Direct numerical simulation of electroconvective instability and hysteretic current-voltage response of a permselective membrane  

E-Print Network (OSTI)

We present a systematic, multiscale, fully detailed numerical modeling for dynamics of fluid flow and ion transport covering Ohmic, limiting, and overlimiting current regimes in conductance of ion-selective membrane. By ...

Pham, Van Sang

292

Simulation of surface waves with porous boundaries in a 2-D numerical wave tank  

E-Print Network (OSTI)

with the BEM solutions. Good agreement is observed between the two independent solutions. After verifying the numerical methods, we studied the interaction of water waves with a porous or rigid bottom-mounted half cylinder. The reflection and transmission...

Koo, Weoncheol

2012-06-07T23:59:59.000Z

293

Numerical simulation on dense gas dispersion and fire characteristics after liquefied natural gas release.  

E-Print Network (OSTI)

??This PhD dissertation mainly studies the prediction, simulation and mitigation methods of the two main hazards in LNG (Liquefied Natural Gas) industry, LNG vapor dense (more)

Sun, Biao

2012-01-01T23:59:59.000Z

294

Numerical simulation of Large Solar Hot Water system in storage tank.  

E-Print Network (OSTI)

??This research is aimed to study the storage tank design parameters effects on the efficiency of the large solar hot water system. Detailed CFD simulation (more)

Shue, Nai-Shen

2012-01-01T23:59:59.000Z

295

EF: Interference in communication (I) Numerical Simulation of Nonlinear Interference in Radio Systems  

E-Print Network (OSTI)

of inter- and intra-system electromagnetic interference (EMI). Using appropriate analysis and simulation Inter. Confer. on Electromagnetic Interference and Compatibility (INCEMIC'97), Dec. 3-5, Hyderabad

Loyka, Sergey

296

NREL Developing a Numerical Simulation Tool to Study Hydrokinetic Energy Conversion Devices and Arrays (Fact Sheet)  

SciTech Connect

New code will help accelerate design improvements by providing a high-fidelity simulation tool to study power performance, structural loading, and the interactions between devices in arrays.

Not Available

2012-02-01T23:59:59.000Z

297

COMPUTATIONAL SIMULATION OF SCRAMJET COMBUSTORS - A COMPARISON BETWEEN QUASI-ONE DIMENSIONAL AND 2-D NUMERICAL SIMULATIONS  

E-Print Network (OSTI)

combustors. The combustor configurations at DLR and NASA's SCHOLAR Supersonic Combustor have been used as test cases for the 1-D and 2-D simulations. Comparisons between the published 3-D computational and experimental results and quasi-one-dimensional and 2...

Tourani, Chandraprakash Chandra

2011-01-26T23:59:59.000Z

298

On numerical simulation of flow, heat transfer and combustion processes in tangentially-fired furnace  

SciTech Connect

In this work, an Eulerian/Lagrangian approach has been employed to investigate numerically flow characteristics, heat transfer and combustion processes inside corner-fired power plant boiler furnace. To avoid pseudo-diffusion that is significant in modeling tangentially-fired furnaces, some attempts have been made at improving the finite-difference scheme. Comparisons have been made between standard {kappa}-{epsilon} model and RNG {kappa}-{epsilon} model. Some new developments on turbulent diffusion of particles are taken into account in an attempt to improve computational accuracy. Finally, temperature deviation is studied numerically so as to gain deeper insight into tangentially fired furnace.

Sun, P.; Fan, J.; Cen, K.

1999-07-01T23:59:59.000Z

299

Effects of aerosol and horizontal inhomogeneity on the broadband albedo of marine stratus: Numerical simulations  

SciTech Connect

Recent estimates of the effect of increasing of anthropogenic sulfate aerosol on the radiative forcing of the atmosphere have indicated that its impact may be comparable in magnitude to the effect from increases in CO{sub 2}. Much of this impact is expected from the effects of the aerosol on cloud microphysics and the subsequent impact on cloud albedo. A solar broadband version of a 2D radiative transfer model was used to quantify the impact of enhanced aerosol concentrations and horizontal inhomogeneity on the solar broadband albedo of marine stratus. The results of the radiative transfer calculations indicated that in unbroken marine stratus clouds the net horizontal transport of photons over a domain of a few kilometers was nearly zero, and the domain-average broadband albedo computed in a 2D cross section was nearly identical to the domain average calculated from a series of independent pixel approximation (IPA) calculations of the same cross section. However, the horizontal inhomogeneity does affect the cloud albedo compared to plane-parallel approximation (PPA) computations due to the nonlinear relationship between albedo and optical depth. The reduction in cloud albedo could be related to the variability of the distribution of log (cloud optical depth). These results extend the finding of Cahalan et al. to broadband solar albedos in a more realistic cloud model and suggest that accurate computation of domain-averaged broadband albedos in unbroken (or nearly unbroken) marine stratus can be made using IPA calculations with 1D radiative transfer models. Computations of the mean albedo over portions of the 3D RAMS domain show the relative increase in cloud albedo due to a 67% increase in the boundary-layer average CCN concentration was between 6% and 9%. The effects of cloud inhomogeneity on the broadband albedo as measured from the PPA bias ranged from 3% to 5%. 25 refs., 8 figs., 4 tabs.

Duda, D.P.; Stephens, G.L.; Stevens, B.; Cotton, W.R. [Colorado State Univ., Fort Collins, CO (United States)] [Colorado State Univ., Fort Collins, CO (United States)

1996-12-15T23:59:59.000Z

300

Numerical Simulation of Wind Tunnel Wall Effects on the Transonic Flow around an Airfoil Model  

Science Journals Connector (OSTI)

For wind tunnel measurements in closed-wall test sections, possible interference effects of the wind tunnel walls play an important role. Three-dimensional TAU simulations were performed for the transonic flow ar...

K. Richter; H. Rosemann

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Numerical simulation of interannual and interdecadal variability of surface wind over the tropical Pacific  

Science Journals Connector (OSTI)

A global atmospheric general circulation model (L9R15 AGCMs) forced by COADS SST was integrated from 1945 to 1993. Interannual and interdecadal variability of the simulated surface wind over the tropical Pacific ...

Wu Ai-ming; Zhao Yong-ping; Bai Xue-zhi

2002-03-01T23:59:59.000Z

302

Two-Dimensional Numerical Simulations of High Efficiency Silicon Solar Cells  

Science Journals Connector (OSTI)

This paper presents for the first time the use of two-dimensional (2D) device simulation for optimising design parameters of high-efficiency silicon solar cells of practical dimensions. We examine the...

G. Heiser; A. G. Aberle; S. R. Wenham

1993-01-01T23:59:59.000Z

303

Numerical simulations and predictive models of undrained penetration in soft soils  

E-Print Network (OSTI)

of rateindependent finite element analyses of pre-embedded penetration depths, and validate the results by upper and lower bound solutions from classical plasticity theory. Furthermore, strain rate effects are modeled by finite element simulations within a framework...

Shi, Han

2005-11-01T23:59:59.000Z

304

Simulation of a Polar Low Case in the North Atlantic with different regional numerical models  

E-Print Network (OSTI)

Matthias Zahn, Hans von Storch University of Hamburg/ GKSS, Matthias.Zahn@gkss.de ABSTRACT In this paper (REgional MOdel) and CLM (CLimate Model) simulations performed at the GKSS with spectral nudging (Feser et

Zahn, Matthias

305

Numerical Simulations of the 1994 Piedmont Flood: Role of Orography and Moist Processes  

Science Journals Connector (OSTI)

The intense precipitation event that occurred between 3 and 6 November 1994 and caused extensive flooding over Piedmont in northwestern Italy is simulated and tested with respect to various physical aspects, using a meteorological mesoscale model ...

Andrea Buzzi; Nazario Tartaglione; Piero Malguzzi

1998-09-01T23:59:59.000Z

306

Mathematical Modeling and Numerical Simulation of Methane Production in a Hydrate Reservoir  

Science Journals Connector (OSTI)

Contrary to more traditional reservoir simulations, the set of model unknowns or primary variables in HydrateResSim changes throughout the simulation as a result of the formation or dissociation of ice and hydrate phases during the simulation. ... For example, in the petroleum industry, CFD models have been developed since the 1970s to help optimize oil production by steam flooding. ... (2) Since the 1980s, an increasing number of problems in environmental engineering, such as the contamination of groundwater due to subsurface leakage of petroleum products, has been a concern for governments and industries that has led to the development of multiphase multicomponent models to simulate the transport of contaminants in the subsurface. ...

Isaac K. Gamwo; Yong Liu

2010-03-10T23:59:59.000Z

307

Numerical simulation of flow of shear-thinning fluids in corrugated channels  

E-Print Network (OSTI)

A numerical study of flow of a shear thinning fluid through a pair of corrugated plates was carried out. The aim of the study was to observe and understand the behavior of the flow of shear thinning fluids through channels were the fluid...

Aiyalur Shankaran, Rohit

2008-10-10T23:59:59.000Z

308

Numerical Simulation of the Flow of a Power Law Fluid in an Elbow Bend  

E-Print Network (OSTI)

A numerical study of flow of power law fluid in an elbow bend has been carried out. The motivation behind this study is to analyze the velocity profiles, especially the pattern of the secondary flow of power law fluid in a bend as there are several...

Kanakamedala, Karthik

2010-07-14T23:59:59.000Z

309

Numerical simulation of flow of shear-thinning fluids in corrugated channels  

E-Print Network (OSTI)

A numerical study of flow of a shear thinning fluid through a pair of corrugated plates was carried out. The aim of the study was to observe and understand the behavior of the flow of shear thinning fluids through channels were the fluid...

Aiyalur Shankaran, Rohit

2009-05-15T23:59:59.000Z

310

American Institute of Aeronautics and Astronautics Numerical Simulation of a Free Molecular Electro Jet  

E-Print Network (OSTI)

production cost Cv = specific heat at constant volume Cp = specific heat at constant pressure R = gas micro-actuators to accelerate the flow in a micro-channel with rarified gas. Numerical modeling thrusters. A finite element based multiscale ionized gas (MIG) flow code utilizing the Galerkin weak

Roy, Subrata

311

Numerical Simulations of Synthetic Jet Based Separation Control in a Canonical Separated Flow  

E-Print Network (OSTI)

first superharmonic is found to result in optimal control of the mean separation bubble. The stability and blunt trailing edge at zero incidence in a free-stream. A separation bubble of prescribed size in terms of local linear stability theory based on the Orr�Sommerfeld equation. The numerical results

Mittal, Rajat

312

Loop Current Mixed Layer Energy Response to Hurricane Lili (2002). Part II: Idealized Numerical Simulations  

E-Print Network (OSTI)

Loop Current Mixed Layer Energy Response to Hurricane Lili (2002). Part II: Idealized Numerical horizontal pressure gradient, wind energy transfer to the mixed layer can be more efficient in such a regime as compared to the case of an initially horizontally homogeneous ocean. However, nearly all energy is removed

Miami, University of

313

Building ventilation : a pressure airflow model computer generation and elements of  

E-Print Network (OSTI)

Building ventilation : a pressure airflow model computer generation and elements of validation H - design #12;1- Introduction Regarding the number of airflow network models found in building publications Abstract : The calculation of airflows is of great importance for detailed building thermal simulation

Paris-Sud XI, Université de

314

Numerical simulation of natural convection of latent heat phase-change-material microcapsulate slurry packed in a horizontal rectangular enclosure heated from below and cooled from above  

Science Journals Connector (OSTI)

A two-dimensional numerical simulation of natural convection in a rectangular enclosure heated from below and cooled from above has been conducted with non-Newtonian phase-change-material (PCM) microcapsulate slu...

Hideo Inaba; Yanlai Zhang; Akihiko Horibe; Naoto Haruki

2007-03-01T23:59:59.000Z

315

A two-dimensional numerical simulation of shock-enhanced mixing in a rectangular scramjet flowfield with parallel hydrogen injection  

SciTech Connect

The effect of shock impingement on the mixing and combustion of a reacting shear-layer is numerically simulated. Hydrogen fuel is injected at sonic velocity behind a backward facing step in a direction parallel to a supersonic freestream vitiated with H{sub 2}O. The two-dimensional Navier-Stokes equations are solved and explicitly coupled to a chemistry package employing a global, two-step combustion model. The results show that shock impingement enhances the mixing and combustion. 17 refs.

Domel, N.D.; Thompson, D.S. (Texas Univ., Arlington (USA))

1991-01-01T23:59:59.000Z

316

Numerical simulations of lab-scale brine-water mixing experiments.  

SciTech Connect

Laboratory-scale experiments simulating the injection of fresh water into brine in a Strategic Petroleum Reserve (SPR) cavern were performed at Sandia National Laboratories for various conditions of injection rate and small and large injection tube diameters. The computational fluid dynamic (CFD) code FLUENT was used to simulate these experiments to evaluate the predictive capability of FLUENT for brine-water mixing in an SPR cavern. The data-model comparisons show that FLUENT simulations predict the mixing plume depth reasonably well. Predictions of the near-wall brine concentrations compare very well with the experimental data. The simulated time for the mixing plume to reach the vessel wall was underpredicted for the small injection tubes but reasonable for the large injection tubes. The difference in the time to reach the wall is probably due to the three-dimensional nature of the mixing plume as it spreads out at the air-brine or oil-brine interface. The depth of the mixing plume as it spreads out along the interface was within a factor of 2 of the experimental data. The FLUENT simulation results predict the plume mixing accurately, especially the water concentration when the mixing plume reaches the wall. This parameter value is the most significant feature of the mixing process because it will determine the amount of enhanced leaching at the oil-brine interface.

Khalil, Imane; Webb, Stephen Walter

2006-10-01T23:59:59.000Z

317

Use of a speed equation for numerical simulation of hydraulic fractures  

E-Print Network (OSTI)

The paper treats the propagation of a hydraulically driven crack. We explicitly write the local speed equation, which facilitates using the theory of propagating interfaces. It is shown that when neglecting the lag between the liquid front and the crack tip, the lubrication PDE yields that a solution satisfies the speed equation identically. This implies that for zero or small lag, the boundary value problem appears ill-posed when solved numerically. We suggest e - regularization, which consists in employing the speed equation together with a prescribed BC on the front to obtain a new BC formulated at a small distance behind the front rather than on the front itself. It is shown that - regularization provides accurate and stable results with reasonable time expense. It is also shown that the speed equation gives a key to proper choice of unknown functions when solving a hydraulic fracture problem numerically.

Linkov, Alexander M

2011-01-01T23:59:59.000Z

318

Particle velocity based universal algorithm for numerical simulation of hydraulic fractures  

E-Print Network (OSTI)

In the paper, we propose a new effective mathematical formulation and resulting universal numerical algorithm capable of tackling various HF models in the framework of a unified approach. The presented numerical scheme is not limited to any particular elasticity model or crack propagation regime. Its basic assumptions are: i) proper choice of independent and dependent variables (with the direct utilization of a new one - the reduced particle velocity), ii) tracing the fracture front by use of the speed equation which can be integrated in a closed form and sets an explicit relation between the crack propagation speed and the coefficients in the asymptotic expansion of the crack opening, iii) proper regularization techniques, iv) improved temporal approximation, v) modular algorithm architecture. The application of the new dependent variable, the reduced particle velocity, instead of the usual fluid flow rate, facilitates the computation of the crack propagation speed from the local relation based on the speed ...

Wrobel, Michal

2014-01-01T23:59:59.000Z

319

Numerical simulation: Toward the design of high-efficiency planar perovskite solar cells  

SciTech Connect

Organo-metal halide perovskite solar cells based on planar architecture have been reported to achieve remarkably high power conversion efficiency (PCE, >16%), rendering them highly competitive to the conventional silicon based solar cells. A thorough understanding of the role of each component in solar cells and their effects as a whole is still required for further improvement in PCE. In this work, the planar heterojunction-based perovskite solar cells were simulated with the program AMPS (analysis of microelectronic and photonic structures)-1D. Simulation results revealed a great dependence of PCE on the thickness and defect density of the perovskite layer. Meanwhile, parameters including the work function of the back contact as well as the hole mobility and acceptor density in hole transport materials were identified to significantly influence the performance of the device. Strikingly, an efficiency over 20% was obtained under the moderate simulation conditions.

Liu, Feng; Zhu, Jun, E-mail: zhujzhu@gmail.com, E-mail: sydai@ipp.ac.cn; Wei, Junfeng; Li, Yi; Lv, Mei [Key Laboratory of Novel Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Yang, Shangfeng [Hefei National Laboratory for Physical Sciences at Microscale, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Zhang, Bing; Yao, Jianxi [State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206 (China); Dai, Songyuan, E-mail: zhujzhu@gmail.com, E-mail: sydai@ipp.ac.cn [Key Laboratory of Novel Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206 (China)

2014-06-23T23:59:59.000Z

320

The effect of dark matter resolution on the collapse of baryons in high redshift numerical simulations  

E-Print Network (OSTI)

We examine the impact of dark matter particle resolution on the formation of a baryonic core in high resolution adaptive mesh refinement simulations. We test the effect that both particle smoothing and particle splitting have on the hydrodynamic properties of a collapsing halo at high redshift (z > 20). Furthermore, we vary the background field intensity, with energy below the Lyman limit ( 100.0$ be satisfied, where ${M_{\\rm{core}}}$ is the enclosed baryon mass within the core and $M_{\\rm{DM}}$ is the minimum dark matter particle mass. This ratio should provide a very useful starting point for conducting convergence tests before any production run simulations. We find that dark matter particle smoothing is a useful adjunct to already highly resolved simulations.

Regan, John A; Wise, John H

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Numerical Simulation of CO2 Sequestration in Natural CO2 Reservoirs on the Colorado Plateau  

NLE Websites -- All DOE Office Websites (Extended Search)

Simulation of CO Simulation of CO 2 Sequestration in Natural CO 2 Reservoirs on the Colorado Plateau Stephen P. White (S.White@irl.cri.nz, (64) 4 5690000) Graham J. Weir (G.Weir@irl.cri.nz, (64) 4 5690000) Warwick M. Kissling (W.Kissling@irl.cri.nz, (64) 4 5690000) Industrial Research Ltd. P.O. Box 31310 Lower Hutt, New Zealand Abstract This paper outlines the proposed research and summarizes pre-project work that forms a basis for a new research program on CO 2 sequestration in saline aquifers. The pre-project work considers storage and disposal of CO 2 several kilometers beneath the surface in generic aquifers and demonstrates the use of reactive chemical transport modeling to simulate mineral sequestration of CO 2. The current research project applies these techniques to particular saline

322

Numerical simulation of the transient photoconductivity in a-Si:H as a function of excitation density  

SciTech Connect

The dependence of the transient photoconductivity induced by pulsed excitation (TPC) on the excitation density is discussed with the help of numerical simulations. It is shown that recombination between excess mobile electrons and all excess holes (mainly localized) can explain the excitation density dependence of the TPC amplitude of standard a-Si:H at room temperature using a rate parameter k{sub BB} of 10{sup {minus}8} cm{sup 3}/s. This model leads to a decay faster than experimentally observed in the time range from 40 ns to 1 {micro}s. A variation of the recombination model is presented that gives short time range. Moreover comparison of the simulations with experimental data yields limits for the parameters of the conduction band tail. In particular, the time necessary to establish a dynamic equilibrium of excess electrons between delocalized states in the conduction band and localized states in the tail appears to be very informative.

Feist, H.; Kunst, M.

1997-07-01T23:59:59.000Z

323

Experimental results and numerical modeling of a high-performance large-scale cryopump. I. Test particle Monte Carlo simulation  

Science Journals Connector (OSTI)

For the torus of the nuclear fusion project ITER (originally the International Thermonuclear Experimental Reactor but also Latin: the way) eight high-performance large-scale customized cryopumps must be designed and manufactured to accommodate the very high pumping speeds and throughputs of the fusion exhaust gas needed to maintain the plasma under stable vacuum conditions and comply with other criteria which cannot be met by standard commercial vacuum pumps. Under an earlier research and development program a model pump of reduced scale based on active cryosorption on charcoal-coated panels at 4.5 K was manufactured and tested systematically. The present article focuses on the simulation of the true three-dimensional complex geometry of the model pump by the newly developed PROVAC3D Monte Carlo code. It is shown for gas throughputs of up to 1000 sccm (?1.69 Pa m3/s at T?=?0 C) in the free molecular regime that the numerical simulation results are in good agreement with the pumping speeds measured. Meanwhile the capture coefficient associated with the virtual region around the cryogenic panels and shields which holds for higher throughputs is calculated using this generic approach. This means that the test particle Monte Carlo simulations in free molecular flow can be used not only for the optimization of the pumping system but also for the supply of the input parameters necessary for the future direct simulation Monte Carlo in the full flow regime.

Xueli Luo; Christian Day; Horst Haas; Stylianos Varoutis

2011-01-01T23:59:59.000Z

324

Experimental results and numerical modeling of a high-performance large-scale cryopump. I. Test particle Monte Carlo simulation  

SciTech Connect

For the torus of the nuclear fusion project ITER (originally the International Thermonuclear Experimental Reactor, but also Latin: the way), eight high-performance large-scale customized cryopumps must be designed and manufactured to accommodate the very high pumping speeds and throughputs of the fusion exhaust gas needed to maintain the plasma under stable vacuum conditions and comply with other criteria which cannot be met by standard commercial vacuum pumps. Under an earlier research and development program, a model pump of reduced scale based on active cryosorption on charcoal-coated panels at 4.5 K was manufactured and tested systematically. The present article focuses on the simulation of the true three-dimensional complex geometry of the model pump by the newly developed ProVac3D Monte Carlo code. It is shown for gas throughputs of up to 1000 sccm ({approx}1.69 Pa m{sup 3}/s at T = 0 deg. C) in the free molecular regime that the numerical simulation results are in good agreement with the pumping speeds measured. Meanwhile, the capture coefficient associated with the virtual region around the cryogenic panels and shields which holds for higher throughputs is calculated using this generic approach. This means that the test particle Monte Carlo simulations in free molecular flow can be used not only for the optimization of the pumping system but also for the supply of the input parameters necessary for the future direct simulation Monte Carlo in the full flow regime.

Luo Xueli; Day, Christian; Haas, Horst; Varoutis, Stylianos [Karlsruhe Institute of Technology, Institute for Technical Physics, 76021 Karlsruhe (Germany)

2011-07-15T23:59:59.000Z

325

Thesis topic: "Characterisation of wake tracking procedures by means of numerical simulation" (Bachelor or master )  

E-Print Network (OSTI)

dynamics in full field. These data are badly needed for validation of so-called wake meandering models and finally methods of aeroelastic simulation of wind turbines in wake. Scope The proposed work aims.jose.trujillo@uni-oldenburg.de Fig. Near wake path of an offshore wind turbine estimatied by means of wake tracking #12;

Peinke, Joachim

326

Numerical simulation of Lewis number effects on lean premixed turbulent flames  

E-Print Network (OSTI)

turbulent flames for lean hydrogen, propane and methane mixtures in two dimensions. Each simulation or syngas, obtained from coal gasification, has sparked interest in the development of burners that can for propane, methane and hydrogen using de- tailed chemistry and transport, corresponding to Le > 1, Le 1

327

American Institute of Aeronautics and Astronautics Numerical Simulations of Plasma Based Flow Control  

E-Print Network (OSTI)

strategies to various flow fields.1-3 One of the major areas for applications of flow control is the gas for reducing losses and improving performance in gas turbine engine component flowfields.6-9 Although many Field, Cleveland, OH 44135 A mathematical model was developed to simulate flow control applications

Jacob, Jamey

328

Numerical Simulation and Experimental Study on Airflow Characteristics in the Plenum of Underfloor Air Supply  

E-Print Network (OSTI)

Energy-efficient and cost-effective space conditioning in offices and other commercial buildings usually use the underfloor space for the supply air static-pressure plenum. The airflow in a plenum of the underfloor air supply was simulated by a...

Li, X.; Li, N.; Fang, F.; Zhao, D.

2006-01-01T23:59:59.000Z

329

Evaluation of models for numerical simulation of the non-neutral region of sheath plasma  

SciTech Connect

Four different electron models are used to simulate the nonequilibrium plasma flow around a representative cylindrical Faraday probe geometry. Each model is implemented in a two-dimensional axisymmetric hybrid electron fluid and particle in cell method. The geometric shadowing model is derived from kinetic theory on the basis that physical obstruction of part of the velocity distribution leads to many of the expected sheath features. The Boltzmann electron fluid model relates the electron density to the plasma potential through the Boltzmann relation. The non-neutral detailed electron fluid model is derived from the electron conservation equations under the assumption of neutrality, and then modified to include non-neutral effects through the electrostatic Poisson equation. The Poisson-consistent detailed electron fluid model is also derived from the conservation equations and the electrostatic Poisson equation, but uses an alternative method that is inherently non-neutral from the outset. Simulations using the geometric shadowing and non-neutral detailed models do not yield satisfactory sheath structures, indicating that these models are not appropriate for sheath simulations. Simulations using the Boltzmann and Poisson-consistent models produce sheath structures that are in excellent agreement with the planar Bohm sheath solution near the centerline of the probe. The computational time requirement for the Poisson-consistent model is much higher than for the Boltzmann model and becomes prohibitive for larger domains.

Boerner, Jeremiah J.; Boyd, Iain D. [Department of Aerospace Engineering, University of Michigan, Ann Arbor, FXB Building, 1320 Beal Avenue, Ann Arbor, Michigan 48109 (United States)

2009-07-15T23:59:59.000Z

330

DIRECT NUMERICAL SIMULATIONS OF REFLECTION-DRIVEN, REDUCED MAGNETOHYDRODYNAMIC TURBULENCE FROM THE SUN TO THE ALFVN CRITICAL POINT  

SciTech Connect

We present direct numerical simulations of inhomogeneous reduced magnetohydrodynamic (RMHD) turbulence between the Sun and the Alfvn critical point. These are the first such simulations that take into account the solar-wind outflow velocity and the radial inhomogeneity of the background solar wind without approximating the nonlinear terms in the governing equations. RMHD turbulence is driven by outward-propagating Alfvn waves (z {sup +} fluctuations) launched from the Sun, which undergo partial non-WKB reflection to produce sunward-propagating Alfvn waves (z {sup } fluctuations). We present 10 simulations with different values of the correlation time ?{sub c{sub sun}{sup +}} and perpendicular correlation length L{sub ?} of outward-propagating Alfvn waves at the coronal base. We find that between 15% and 33% of the z {sup +} energy launched into the corona dissipates between the coronal base and Alfvn critical point. Between 33% and 40% of this input energy goes into work on the solar-wind outflow, and between 22% and 36% escapes as z {sup +} fluctuations through the simulation boundary at r = r{sub A}. The z {sup } power spectra scale like k{sub perpendicular}{sup -?{sup }}, where k is the wavenumber in the plane perpendicular to B{sub 0}. In our simulation with the smallest value of ?{sub c{sub sun}{sup +}} (?2 minutes) and largest value of L{sub ?} (2 10{sup 4} km), we find that ?{sup +} decreases approximately linearly with increasing ln (r), reaching a value of 1.3 at r = 11.1 R{sub ?}. Our simulations with larger values of ?{sub c{sub sun}{sup +}} exhibit alignment between the contours of constant ?{sup +}, ?{sup }, ?{sub 0}{sup +}, and ?{sub 0}{sup -}, where ?{sup } are the Elssser potentials and ?{sub 0}{sup } are the outer-scale parallel Elssser vorticities.

Perez, Jean Carlos; Chandran, Benjamin D. G. [Space Science Center, University of New Hampshire, Durham, NH 03824 (United States)

2013-10-20T23:59:59.000Z

331

The NINJA-2 project: Detecting and characterizing gravitational waveforms modelled using numerical binary black hole simulations  

E-Print Network (OSTI)

The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational-wave astrophysics communities. The purpose of NINJA is to study the ability to detect gravitational waves emitted from merging binary black holes and recover their parameters with next-generation gravitational-wave observatories. We report here on the results of the second NINJA project, NINJA-2, which employs 60 complete binary black hole hybrid waveforms consisting of a numerical portion modelling the late inspiral, merger, and ringdown stitched to a post-Newtonian portion modelling the early inspiral. In a "blind injection challenge" similar to that conducted in recent LIGO and Virgo science runs, we added 7 hybrid waveforms to two months of data recolored to predictions of Advanced LIGO and Advanced Virgo sensitivity curves during their first observing runs. The resulting data was analyzed by gravitational-wave detection algorithms and 6 of the waveforms were recovered with false alarm rates smaller than 1 in a thousand years. Parameter estimation algorithms were run on each of these waveforms to explore the ability to constrain the masses, component angular momenta and sky position of these waveforms. We also perform a large-scale monte-carlo study to assess the ability to recover each of the 60 hybrid waveforms with early Advanced LIGO and Advanced Virgo sensitivity curves. Our results predict that early Advanced LIGO and Advanced Virgo will have a volume-weighted average sensitive distance of 300Mpc (1Gpc) for $10M_{\\odot}+10M_{\\odot}$ ($50M_{\\odot}+50M_{\\odot}$) binary black hole coalescences. We demonstrate that neglecting the component angular momenta in the waveform models used in matched-filtering will result in a reduction in sensitivity for systems with large component angular momenta. [Abstract abridged for ArXiv, full version in PDF

The LIGO Scientific Collaboration; the Virgo Collaboration; the NINJA-2 Collaboration; :; J. Aasi; B. P. Abbott; R. Abbott; T. Abbott; M. R. Abernathy; T. Accadia; F. Acernese; K. Ackley; C. Adams; T. Adams; P. Addesso; R. X. Adhikari; C. Affeldt; M. Agathos; N. Aggarwal; O. D. Aguiar; A. Ain; P. Ajith; A. Alemic; B. Allen; A. Allocca; D. Amariutei; M. Andersen; R. Anderson; S. B. Anderson; W. G. Anderson; K. Arai; M. C. Araya; C. Arceneaux; J. Areeda; S. M. Aston; P. Astone; P. Aufmuth; C. Aulbert; L. Austin; B. E. Aylott; S. Babak; P. T. Baker; G. Ballardin; S. W. Ballmer; J. C. Barayoga; M. Barbet; B. C. Barish; D. Barker; F. Barone; B. Barr; L. Barsotti; M. Barsuglia; M. A. Barton; I. Bartos; R. Bassiri; A. Basti; J. C. Batch; J. Bauchrowitz; Th. S. Bauer; B. Behnke; M. Bejger; M. G. Beker; C. Belczynski; A. S. Bell; C. Bell; G. Bergmann; D. Bersanetti; A. Bertolini; J. Betzwieser; P. T. Beyersdorf; I. A. Bilenko; G. Billingsley; J. Birch; S. Biscans; M. Bitossi; M. A. Bizouard; E. Black; J. K. Blackburn; L. Blackburn; D. Blair; S. Bloemen; M. Blom; O. Bock; T. P. Bodiya; M. Boer; G. Bogaert; C. Bogan; C. Bond; F. Bondu; L. Bonelli; R. Bonnand; R. Bork; M. Born; V. Boschi; Sukanta Bose; L. Bosi; C. Bradaschia; P. R. Brady; V. B. Braginsky; M. Branchesi; J. E. Brau; T. Briant; D. O. Bridges; A. Brillet; M. Brinkmann; V. Brisson; A. F. Brooks; D. A. Brown; D. D. Brown; F. Brckner; S. Buchman; T. Bulik; H. J. Bulten; A. Buonanno; R. Burman; D. Buskulic; C. Buy; L. Cadonati; G. Cagnoli; J. Caldern Bustillo; E. Calloni; J. B. Camp; P. Campsie; K. C. Cannon; B. Canuel; J. Cao; C. D. Capano; F. Carbognani; L. Carbone; S. Caride; A. Castiglia; S. Caudill; M. Cavagli; F. Cavalier; R. Cavalieri; C. Celerier; G. Cella; C. Cepeda; E. Cesarini; R. Chakraborty; T. Chalermsongsak; S. J. Chamberlin; S. Chao; P. Charlton; E. Chassande-Mottin; X. Chen; Y. Chen; A. Chincarini; A. Chiummo; H. S. Cho; J. Chow; N. Christensen; Q. Chu; S. S. Y. Chua; S. Chung; G. Ciani; F. Clara; J. A. Clark; F. Cleva; E. Coccia; P. -F. Cohadon; A. Colla; C. Collette; M. Colombini; L. Cominsky; M. Constancio Jr.; A. Conte; D. Cook; T. R. Corbitt; M. Cordier; N. Cornish; A. Corpuz; A. Corsi; C. A. Costa; M. W. Coughlin; S. Coughlin; J. -P. Coulon; S. Countryman; P. Couvares; D. M. Coward; M. Cowart; D. C. Coyne; R. Coyne; K. Craig; J. D. E. Creighton; S. G. Crowder; A. Cumming; L. Cunningham; E. Cuoco; K. Dahl; T. Dal Canton; M. Damjanic; S. L. Danilishin; S. D'Antonio; K. Danzmann; V. Dattilo; H. Daveloza; M. Davier; G. S. Davies; E. J. Daw; R. Day; T. Dayanga; G. Debreczeni; J. Degallaix; S. Delglise; W. Del Pozzo; T. Denker; T. Dent; H. Dereli; V. Dergachev; R. De Rosa; R. T. DeRosa; R. DeSalvo; S. Dhurandhar; M. Daz; L. Di Fiore; A. Di Lieto; I. Di Palma; A. Di Virgilio; A. Donath; F. Donovan; K. L. Dooley; S. Doravari; S. Dossa; R. Douglas; T. P. Downes; M. Drago; R. W. P. Drever; J. C. Driggers; Z. Du; S. Dwyer; T. Eberle; T. Edo; M. Edwards; A. Effler; H. Eggenstein; P. Ehrens; J. Eichholz; S. S. Eikenberry; G. Endr?czi; R. Essick; T. Etzel; M. Evans; T. Evans; M. Factourovich; V. Fafone; S. Fairhurst; Q. Fang; S. Farinon; B. Farr; W. M. Farr; M. Favata; H. Fehrmann; M. M. Fejer; D. Feldbaum; F. Feroz; I. Ferrante; F. Ferrini; F. Fidecaro; L. S. Finn; I. Fiori; R. P. Fisher; R. Flaminio; J. -D. Fournier; S. Franco; S. Frasca; F. Frasconi; M. Frede; Z. Frei; A. Freise; R. Frey; T. T. Fricke; P. Fritschel; V. V. Frolov; P. Fulda; M. Fyffe; J. Gair; L. Gammaitoni; S. Gaonkar; F. Garufi; N. Gehrels; G. Gemme; E. Genin; A. Gennai; S. Ghosh; J. A. Giaime; K. D. Giardina; A. Giazotto; C. Gill; J. Gleason; E. Goetz; R. Goetz; L. Gondan; G. Gonzlez; N. Gordon; M. L. Gorodetsky; S. Gossan; S. Goler; R. Gouaty; C. Grf; P. B. Graff; M. Granata; A. Grant; S. Gras; C. Gray; R. J. S. Greenhalgh; A. M. Gretarsson; P. Groot; H. Grote; K. Grover; S. Grunewald; G. M. Guidi; C. Guido; K. Gushwa; E. K. Gustafson; R. Gustafson; D. Hammer; G. Hammond; M. Hanke; J. Hanks; C. Hanna; J. Hanson; J. Harms; G. M. Harry; I. W. Harry; E. D. Harstad; M. Hart; M. T. Hartman; C. -J. Haster; K. Haughian; A. Heidmann; M. Heintze; H. Heitmann; P. Hello; G. Hemming; M. Hendry; I. S. Heng; A. W. Heptonstall; M. Heurs; M. Hewitson; S. Hild; D. Hoak; K. A. Hodge; K. Holt; S. Hooper; P. Hopkins; D. J. Hosken; J. Hough; E. J. Howell; Y. Hu; B. Hughey; S. Husa; S. H. Huttner; M. Huynh; T. Huynh-Dinh; D. R. Ingram; R. Inta; T. Isogai; A. Ivanov; B. R. Iyer; K. Izumi; M. Jacobson; E. James; H. Jang; P. Jaranowski; Y. Ji; F. Jimnez-Forteza; W. W. Johnson; D. I. Jones; R. Jones; R. J. G. Jonker; L. Ju; Haris K; P. Kalmus; V. Kalogera; S. Kandhasamy; G. Kang; J. B. Kanner; J. Karlen; M. Kasprzack; E. Katsavounidis; W. Katzman; H. Kaufer; K. Kawabe; F. Kawazoe; F. Kflian; G. M. Keiser; D. Keitel; D. B. Kelley; W. Kells; A. Khalaidovski

2014-01-05T23:59:59.000Z

332

NUMERICAL SIMULATIONS OF CHROMOSPHERIC ANEMONE JETS ASSOCIATED WITH MOVING MAGNETIC FEATURES  

SciTech Connect

Observations with the space-based solar observatory Hinode show that small-scale magnetic structures in the photosphere are found to be associated with a particular class of jets of plasma in the chromosphere called anemone jets. The goal of our study is to conduct a numerical experiment of such chromospheric anemone jets related to the moving magnetic features (MMFs). We construct a 2.5 dimensional numerical MHD model to describe the process of magnetic reconnection between the MMFs and the pre-existing ambient magnetic field, which is driven by the horizontal motion of the magnetic structure in the photosphere. We include thermal conduction parallel to the magnetic field and optically thin radiative losses in the corona to account for a self-consistent description of the evaporation process during the heating of the plasma due to the reconnection process. The motion of the MMFs leads to the expected jet and our numerical results can reproduce many observed characteristics of chromospheric anemone jets, topologically and quantitatively. As a result of the tearing instability, plasmoids are generated in the reconnection process that are consistent with the observed bright moving blobs in the anemone jets. An increase in the thermal pressure at the base of the jet is also driven by the reconnection, which induces a train of slow-mode shocks propagating upward. These shocks are a secondary effect, and only modulate the outflow of the anemone jet. The jet itself is driven by the energy input due to the reconnection of the MMFs and the ambient magnetic field.

Yang, Liping; He, Jiansen; Tu, Chuanyi; Zhang, Lei [School of Earth and Space Sciences, Peking University, 100871 Beijing (China); Peter, Hardi [Max Planck Institute for Solar System Research, D-37191 Katlenburg-Lindau (Germany); Feng, Xueshang [SIGMA Weather Group, State Key Laboratory for Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, 100871 Beijing (China); Zhang, Shaohua, E-mail: jshept@gmail.com [Institute of Geology and Geophysics, Chinese Academy of Sciences, 100871 Beijing (China)

2013-11-01T23:59:59.000Z

333

Numerical simulation and wind tunnel studies of pollution dispersion in an isolated street canyon  

Science Journals Connector (OSTI)

A three dimensional numerical modelling study of an urban isolated street canyon are done using Computational Fluid Dynamics (CFD) software FLUENT. The concentration predictions of FLUENT are compared with the Environmental Wind Tunnel (EWT) test results conducted at Indian Institute of Technology, Delhi for the Aspect Ratio (AR) of 1 and 1.5 at perpendicular wind direction. In FLUENT, three different k??? turbulence models, i.e., standard, Renormalisation Group (RNG) and realisable, are used. RNG model has been found to be best matched with the wind tunnel results (d = 0.80) for AR = 1, showing that for separated flows, it works best.

Seema Awasthi; K.K. Chaudhry

2009-01-01T23:59:59.000Z

334

Numerical simulation and experiment investigating the performance of a capacitance sensor measuring the humidity of wet steam  

Science Journals Connector (OSTI)

The humidity of steam is an important parameter, but its exact measurement is difficult. The use of capacitance is a novel measurement method. On the basis of the theory of dielectric polarization and hydrodynamics and applying FLUENT UDF language, the coupling of the steam flow field and electric field within the capacitance sensor are investigated through numerical simulation. The standard ke model, scalable wall function and SIMPLE (Semi-Implicit Method for Pressure Linked Equations) are used in the research. Additionally, steam humidity is measured according to capacitance in an experiment. The results show that the water molecule is polarized; polarized charge appears near the wall of the flow field; the radial velocity depends on whether there is an electric field within the capacitance sensor, with the dependence being greatest near the outermost board; and the electric field intensity near the electrode board is less when there is no flow field. The numerical simulation agrees with the results of the experiment. The capacitance does not depend on a change in steam flow, and the capacitance of the sensor increases linearly with humidity.

Du Lipeng; Tian Ruifeng; Zhang Pengfei; Sun Zhongning

2011-01-01T23:59:59.000Z

335

Numerical simulation of combined natural and forced convection during thermal-hydraulic transients. [LMFBR  

SciTech Connect

The single-phase COMMIX (COMponent MIXing) computer code performs fully three-dimensional, transient, thermal-hydraulic analyses of liquid-sodium LMFBR components. It solves the conservation equations of mass, momentum, and energy as a boundary-value problem in space and as an initial-value problem in time. The concepts of volume porosity, surface permeability and distributed resistance, and heat source have been employed in quasi-continuum (rod-bundle) applications. Results from three transient simulations involving forced and natural convection are presented: (1) a sodium-filled horizontal pipe initially of uniform temperature undergoing an inlet velocity rundown transient, as well as an inlet temperature transient; (2) a 19-pin LMFBR rod bundle undergoing a velocity transient; and, (3) a simulation of a water test of a 1/10-scale outlet plenum undergoing both velocity and temperature transients.

Domanus, H.M.; Sha, W.T.

1981-01-01T23:59:59.000Z

336

Numerical Simulations of Optically Thick Accretion onto a Black Hole - II. Rotating Flow  

E-Print Network (OSTI)

In this paper we report on recent upgrades to our general relativistic radiation magnetohydrodynamics code, Cosmos++, including the development of a new primitive inversion scheme and a hybrid implicit-explicit solver with a more general closure relation for the radiation equations. The new hybrid solver helps stabilize the treatment of the radiation source terms, while the new closure allows for a much broader range of optical depths to be considered. These changes allow us to expand by orders of magnitude the range of temperatures, opacities, and mass accretion rates, and move a step closer toward our goal of performing global simulations of radiation-pressure-dominated black hole accretion disks. In this work we test and validate the new method against an array of problems. We also demonstrate its ability to handle super-Eddington, quasi-spherical accretion. Even with just a single proof-of-principle simulation, we already see tantalizing hints of the interesting phenomenology associated with the coupling ...

Fragile, P Chris; Anninos, Peter

2014-01-01T23:59:59.000Z

337

High-level numerical simulations of noise in CCD and CMOS photosensors: review and tutorial  

E-Print Network (OSTI)

In many applications, such as development and testing of image processing algorithms, it is often necessary to simulate images containing realistic noise from solid-state photosensors. A high-level model of CCD and CMOS photosensors based on a literature review is formulated in this paper. The model includes photo-response non-uniformity, photon shot noise, dark current Fixed Pattern Noise, dark current shot noise, offset Fixed Pattern Noise, source follower noise, sense node reset noise, and quantisation noise. The model also includes voltage-to-voltage, voltage-to-electrons, and analogue-to-digital converter non-linearities. The formulated model can be used to create synthetic images for testing and validation of image processing algorithms in the presence of realistic images noise. An example of the simulated CMOS photosensor and a comparison with a custom-made CMOS hardware sensor is presented. Procedures for characterisation from both light and dark noises are described. Experimental results that confirm...

Konnik, Mikhail

2014-01-01T23:59:59.000Z

338

Coalescence kinetics in surfactant stabilized emulsions: Evolution equations from direct numerical simulations  

SciTech Connect

Lattice Boltzmann simulations were used to study the coalescence kinetics in emulsions with amphiphilic surfactant, under neutrally buoyant conditions, and with a significant kinematic viscosity contrast between the phases (emulating water in oil emulsions). The 3D simulation domain was large enough (256 3rd power -- 10 7th power grid points) to obtain good statistics with droplet numbers ranging from a few thousand at early times to a few hundred near equilibrium. Increased surfactant contents slowed down the coalescence rate between droplets due to the Gibbs-Marangoni effect, and the coalescence was driven by a quasi-turbulent velocity field. The kinetic energy decayed at a relatively slow rate at early times, due to conversion of interfacial energy to kinetic energy in the flow during coalescence. Phenomenological, coupled differential equations for the mean droplet diameter D(t) and the number density nd(t) were obtained from the simulation data and from film draining theories. Local (in time) power law exponents for the growth of the mean diameter (and for the concomitant decrease of nd) were established in terms of the instantaneous values of the kinetic energy, coalescence probability, Gibbs elasticity, and interfacial area. The model studies indicated that true power laws for the growth of the droplet size and decrease of the number of droplets with time may not be justified, since the exponents derived using the phenomenological model were time dependent. In contrast to earlier simulation results for symmetric blends with surfactant, we found no evidence for stretched logarithmic scaling of the formD -- [ln (ct)]a for the morphology length, or exponential scalings associated with arrested growth, on the basis of the phenomenological model.

R. Skartlien; E. Sollum; A. Akselsen; P. Meakin; B. Grimes; J. Sjoblom

2012-12-01T23:59:59.000Z

339

Aircraft Measurements and Numerical Simulations of Gravity Waves in the Extratropical  

E-Print Network (OSTI)

of RF-02 in START08 1.67km WRF simulations at 1800 UTC 04/22/2008 (1600 MDT 04/21/2008) Grey Shaded Area: 9km Wind Speed (m/s) Blue/Red Contour: 12.5km Divergence (pos/neg) Divergence at Flight Height Black Contour: 9km Pressure Vector: 9km Wind Field (m/s) O A B C #12;Spectral Analysis of Aircraft Measurements

Thompson, Anne

340

Numerical simulation study on fluid dynamics of plasma window using argon  

SciTech Connect

In this paper, a numerical 2D FLUENT-based magneto-hydrodynamic model has been developed to investigate the arc and flow field of plasma window, which is used as a windowless vacuum sealing device. The gas inlet, arc creation-developing and plasma expansion segments are all incorporated together in the integral model. An axis-symmetry cathode structure (hollow cathode) is used in the model. Current distribution of the arc is presented and discussed. The temperature, velocity, and pressure field are presented to show the physical mechanisms for the high pressure gap within the plasma window. Flow acceleration and viscosity effect are concluded as the main reasons for the pressure drop. The result for the pressure distribution in the cylindrical tube section has a good agreement with the analytical model. The validation for the sealing ability of plasma window is verified.

Huang, S.; Zhu, K.; Shi, B. L.; Lu, Y. R. [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China)] [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Hershcovitch, A. [Brookhaven National Laboratory, New York 11973-5000 (United States)] [Brookhaven National Laboratory, New York 11973-5000 (United States); Yang, L.; Zhang, X. Y.; Wei, G. D. [Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000 (China)] [Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000 (China)

2013-07-15T23:59:59.000Z

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Use of Silicon Carbide as Beam Intercepting Device Material: Tests, Issues and Numerical Simulations  

E-Print Network (OSTI)

Silicon Carbide (SiC) stands as one of the most promising ceramic material with respect to its thermal shock resistance and mechanical strengths. It has hence been considered as candidate material for the development of higher performance beam intercepting devices at CERN. Its brazing with a metal counterpart has been tested and characterized by means of microstructural and ultrasound techniques. Despite the positive results, its use has to be evaluated with care, due to the strong evidence in literature of large and permanent volumetric expansion, called swelling, under the effect of neutron and ion irradiation. This may cause premature and sudden failure, and can be mitigated to some extent by operating at high temperature. For this reason limited information is available for irradiation below 100C, which is the typical temperature of interest for beam intercepting devices like dumps or collimators. This paper describes the brazing campaign carried out at CERN, the results, and the theoretical and numeric...

Delonca, M; Gil Costa, M; Vacca, A

2014-01-01T23:59:59.000Z

342

Numerical simulation of the two-dimensional flow in high pressure catalytic combustor for gas turbine  

Science Journals Connector (OSTI)

The objective of this paper is modeling the mechanism of high pressure and high temperature catalytic oxidation of natural gas, or methane. The model is two-dimensional steady-state, and includes axial and radial convection and diffusion of mass, momentum and energy, as well as homogeneous (gas phase) and heterogeneous (gas surface) single step irreversible chemical reactions within a catalyst channel. Experimental investigations were also made of natural gas, or methane combustion in the presence of Mn-substituted hexaaluminate catalysts. Axial profiles of catalyst wall temperature, and gas temperature and gas composition for a range of gas turbine combustor operating conditions have been obtained for comparison with and development of a computer model of catalytic combustion. Numerical calculation results for atmospheric pressure agree well with experimental data. The calculations have been extended for high pressure (10 atm) operating conditions of gas turbine.

Y. Tsujikawa; S. Fujii; H. Sadamori; S. Ito; S. Katsura

1995-01-01T23:59:59.000Z

343

Methane Hydrate Dissociation by Depressurization in a Mount Elbert Sandstone Sample: Experimental Observations and Numerical Simulations  

SciTech Connect

A preserved sample of hydrate-bearing sandstone from the Mount Elbert Test Well was dissociated by depressurization while monitoring the internal temperature of the sample in two locations and the density changes at high spatial resolution using x-ray CT scanning. The sample contained two distinct regions having different porosity and grain size distributions. The hydrate dissociation occurred initially throughout the sample as a result of depressing the pressure below the stability pressure. This initial stage reduced the temperature to the equilibrium point, which was maintained above the ice point. After that, dissociation occurred from the outside in as a result of heat transfer from the controlled temperature bath surrounding the pressure vessel. Numerical modeling of the test using TOUGH+HYDRATE yielded a gas production curve that closely matches the experimentally measured curve.

Kneafsey, T.; Moridis, G.J.

2011-01-15T23:59:59.000Z

344

Numerical Simulation of Micro?atmospheric Environment by LES in a District of Beijing  

Science Journals Connector (OSTI)

This paper investigates wind field and traffic pollutant dispersion at street level in a local urban area. A coupling method is employed between the mesoscale model weather research and forecast (WRF) for the atmospheric flow of whole city and the large eddy simulation (LES) method for local environmental flows. A combined model is proposed for building clusters in the urban area. The wind speed temperature and carbon monoxide concentration fields are computed from 9 am of October 26 2009 to 8 am of the next day in a district of Beijing and the results show a good agreement with the observation.

Y. S. Liu; S. G. Miao; C. L. Zhang; G. X. Cui; Z. S. Zhang

2011-01-01T23:59:59.000Z

345

Modeling-Computer Simulations At Walker-Lane Transitional Zone...  

Open Energy Info (EERE)

and earthquake-monitoring projects, and data donated from mining, geothermal, and petroleum companies. We also collected (May 2002 and August 2004) two new crustal refraction...

346

Modeling-Computer Simulations At Dixie Valley Geothermal Area...  

Open Energy Info (EERE)

is currently being utilized. References B. M. Kennedy, M. C. van Soest (2006) A Helium Isotope Perspective On The Dixie Valley, Nevada, Hydrothermal System Additional References...

347

Modeling-Computer Simulations (Ranalli & Rybach, 2005) | Open...  

Open Energy Info (EERE)

Notes re: Heat Flow and Temp Logs References G. Ranalli, L. Rybach (2005) Heat Flow, Heat Transfer And Lithosphere Rheology In Geothermal Areas- Features And Examples...

348

Modeling-Computer Simulations At Long Valley Caldera Geothermal...  

Open Energy Info (EERE)

and components of two continuous GPS time series. Additionally, the model explains the spatial extent of deformation observed by InSAR data covering the 1997-98 inflation...

349

Modeling-Computer Simulations At Valles Caldera - Sulphur Springs...  

Open Energy Info (EERE)

Keiiti Aki, Michael C. Fehler (1995) A Shallow Attenuating Anomaly Inside The Ring Fracture Of The Valles Caldera, New Mexico Additional References Retrieved from "http:...

350

Modeling-Computer Simulations At Valles Caldera - Redondo Geothermal...  

Open Energy Info (EERE)

Keiiti Aki, Michael C. Fehler (1995) A Shallow Attenuating Anomaly Inside The Ring Fracture Of The Valles Caldera, New Mexico Additional References Retrieved from "http:...

351

Modeling-Computer Simulations At Northern Basin & Range Region...  

Open Energy Info (EERE)

systems References D. D. Blackwell, K. W. Wisian, M. C. Richards, Mark Leidig, Richard Smith, Jason McKenna (2003) Geothermal Resource Analysis And Structure Of Basin And Range...

352

Modeling-Computer Simulations At Nw Basin & Range Region (Blackwell...  

Open Energy Info (EERE)

systems References D. D. Blackwell, K. W. Wisian, M. C. Richards, Mark Leidig, Richard Smith, Jason McKenna (2003) Geothermal Resource Analysis And Structure Of Basin And Range...

353

Modeling-Computer Simulations At Dixie Valley Geothermal Area...  

Open Energy Info (EERE)

vein structure associated with ore deposits. References David D. Blackwell, Richard P. Smith, Al Waibel, Maria C. Richards, Patrick Stepp (2009) Why Basin and Range Systems are...

354

Modeling-Computer Simulations At Central Nevada Seismic Zone...  

Open Energy Info (EERE)

systems References D. D. Blackwell, K. W. Wisian, M. C. Richards, Mark Leidig, Richard Smith, Jason McKenna (2003) Geothermal Resource Analysis And Structure Of Basin And Range...

355

Modeling-Computer Simulations At Northern Basin & Range Region...  

Open Energy Info (EERE)

Unknown References Glenn Biasi, Leiph Preston, Ileana Tibuleac (2009) Body Wave Tomography For Regional Scale Assessment Of Geothermal Indicators In The Western Great Basin...

356

Modeling-Computer Simulations At Central Nevada Seismic Zone...  

Open Energy Info (EERE)

Unknown References Glenn Biasi, Leiph Preston, Ileana Tibuleac (2009) Body Wave Tomography For Regional Scale Assessment Of Geothermal Indicators In The Western Great Basin...

357

Modeling-Computer Simulations At Walker-Lane Transitional Zone...  

Open Energy Info (EERE)

Unknown References Glenn Biasi, Leiph Preston, Ileana Tibuleac (2009) Body Wave Tomography For Regional Scale Assessment Of Geothermal Indicators In The Western Great Basin...

358

Modeling-Computer Simulations At Nw Basin & Range Region (Biasi...  

Open Energy Info (EERE)

Unknown References Glenn Biasi, Leiph Preston, Ileana Tibuleac (2009) Body Wave Tomography For Regional Scale Assessment Of Geothermal Indicators In The Western Great Basin...

359

Numerical simulation of thin-shell direct drive DHe3-filled capsules fielded at OMEGA  

SciTech Connect

Thin-shell deuterium-helium-3 (DHe{sup 3}) filled glass capsules on the Omega laser provide a fast-implosion experimental platform for developing separate time-resolved measurements of ion, electron, and radiation temperatures in nonequilibrium plasmas. Dynamically significant non-local thermodynamic equilibrium (NLTE) conditions are created by the addition of xenon dopant to the DHe{sup 3} gas fill, in quantities sufficient to have an impact on yields, compression, and cooling rates. The high-Z dopant dramatically increases the radiative cooling rate in the plasma, allowing it to collapse in compressions that can be an order of magnitude higher than in undoped capsules. A baseline LASNEX simulation model using detailed configuration accounting NLTE atomic physics shows very good agreement with the data for doped as well as undoped capsules, while other models either underpredict or overpredict the radiative cooling enhancement. The baseline model captures the behavior of the capsule when the D:He{sup 3} ratio is varied well away from equimolar, suggesting no yield anomaly with either nearly pure deuterium or He{sup 3} fills. Variation of the electron-ion coupling in the baseline simulation model shows agreement with the data for a coupling multiplier that is within 20% of unity. Reliably inferring electron-ion coupling strength from the data is complicated by uncertainties in the hydrodynamic mix and other parameters, but many of these can be mitigated in follow-on experiments at the National Ignition Facility.

Miles, A. R.; Chung, H.-K.; Heeter, R.; Hsing, W.; Koch, J. A.; Park, H.-S.; Robey, H. F.; Scott, H. A.; Tommasini, R. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Frenje, J.; Li, C. K.; Petrasso, R. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Glebov, V. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Lee, R. W. [SLAC Linear Coherent Light Source, Menlo Park, California 94025 (United States)

2012-07-15T23:59:59.000Z

360

Numerical simulation of a blanket cooling system for fusion reactor based on PWR conditions  

Science Journals Connector (OSTI)

The simulations of a blanket cooling system were presented to address the choice of cooling channel geometry and coolant input data which are related to blanket engineering implementation. This work was performed using computer aided design (CAD) and computational fluid dynamics (CFD) technology. Simulations were carried out for the blanket module with a size of 0.6mנ0.45m in toroidal plane, and the nuclear heat was applied on the cooling system at Pn (neutron wall load) of 5MW/m2. The structure factors and input data of hydraulics were investigated to explore the optimal parameters to match the PWR condition. It was found that the inlet velocity of first wall (FW) channel should be within the range of 2.483.34m/s. As a result, the temperature rise (TR) of the coolant in the FW channel would be 2425K. This leads to the remaining space for TR within the range of 15K in the piping circuits. It also indicated that the FW plays an important role in TR (reaches 60% of the whole cooling system) due to its high level of Pn and heat flux in the zones. It was predicted that the nuclear heat inside blanket module could be removed completely by the piping circuits with an acceptable pipe bore and the related input data. Finally, a possible design range of cooling parameters was proposed in view of engineering feasibility and blanket neutronics design.

Changle Liu; Jianzhong Zhang; Yinfeng Zhu; Songlin Liu; Xuebin Ma; Peiming Chen

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Mapping galaxy encounters in numerical simulations: The spatial extent of induced star formation  

E-Print Network (OSTI)

We employ a suite of 75 simulations of galaxies in idealised major mergers (stellar mass ratio ~2.5:1), with a wide range of orbital parameters, to investigate the spatial extent of interaction-induced star formation. Although the total star formation in galaxy encounters is generally elevated relative to isolated galaxies, we find that this elevation is a combination of intense enhancements within the central kpc and moderately suppressed activity at large galacto-centric radii. The radial dependence of the star formation enhancement is stronger in the less massive galaxy than in the primary, and is also more pronounced in mergers of more closely aligned disc spin orientations. Conversely, these trends are almost entirely independent of the encounter's impact parameter and orbital eccentricity. Our predictions of the radial dependence of triggered star formation, and specifically the suppression of star formation beyond kph-scales, will be testable with the next generation of integral-field spectroscopic sur...

Moreno, Jorge; Ellison, Sara L; Patton, David R; Bluck, Asa F L; Bansal, Gunjan; Hernquist, Lars

2015-01-01T23:59:59.000Z

362

Numerical simulation of the stochastic dynamics of inclusions in biomembranes in presence of surface tension  

E-Print Network (OSTI)

The stochastic dynamics of inclusions in a randomly fluctuating biomembrane is simulated. These inclusions can represent the embedded proteins and the external particles arriving at a cell membrane. The energetics of the biomembrane is modelled via the Canham-Helfrich Hamiltonian. The contributions of both the bending elastic-curvature energy and the surface tension of the biomembrane are taken into account. The biomembrane is treated as a two-dimensional sheet whose height variations from a reference frame is treated as a stochastic Wiener process. The lateral diffusion parameter associated with this Wiener process coupled with the longitudinal diffusion parameter obtained from the standard Einsteinian diffusion theory completely determine the stochastic motion of the inclusions. It is shown that the presence of surface tension significantly affects the overall dynamics of the inclusions, particularly the rate of capture of the external inclusions, such as drug particles, at the site of the embedded inclusions, such as the embedded proteins.

H. Rafii-Tabar; H. R. Sepangi

2005-08-30T23:59:59.000Z

363

PROBABILISTIC SIMULATION OF SUBSURFACE FLUID FLOW: A STUDY USING A NUMERICAL SCHEME  

SciTech Connect

There has been an increasing interest in probabilistic modeling of hydrogeologic systems. The classical approach to groundwater modeling has been deterministic in nature, where individual layers and formations are assumed to be uniformly homogeneous. Even in the case of complex heterogeneous systems, the heterogeneities describe the differences in parameter values between various layers, but not within any individual layer. In a deterministic model a single-number is assigned to each hydrogeologic parameter, given a particular scale of interest. However, physically there is no such entity as a truly uniform and homogeneous unit. Single-number representations or deterministic predictions are subject to uncertainties. The approach used in this work models such uncertainties with probabilistic parameters. The resulting statistical distributions of output variables are analyzed. A numerical algorithm, based on axiomatic principles of probability theory, performs arithmetic operations between probability distributions. Two subroutines are developed from the algorithm and incorporated into the computer program TERZAGI, which solves groundwater flow problems in saturated, multi-dimensional systems. The probabilistic computer program is given the name, PROGRES. The algorithm has been applied to study the following problems: one-dimensional flow through homogeneous media, steady-state and transient flow conditions, one-dimensional flow through heterogeneous media, steady-state and transient flow conditions, and two-dimensional steady-stte flow through heterogeneous media. The results are compared with those available in the literature.

Buscheck, Timothy Eric

1980-03-01T23:59:59.000Z

364

Experiment and Numerical Simulation of Bubble Behaviors in Argon Gas Injection Into Lead-Bismuth Pool  

SciTech Connect

In a lead-bismuth alloy (45%Pb-55%Bi) cooled direct contact boiling water fast reactor (PBWFR), steam can be produced by direct contact of feed water with primary Pb-Bi coolant in the upper core plenum, and Pb-Bi coolant can be circulated by buoyancy forces of steam bubbles. As a basic study to investigate the two-phase flow characteristics in the chimneys of PBWFR, a two-dimensional two-phase flow was simulated by injecting argon gas into Pb-Bi pool in a rectangular vessel (400 mm in length, 1500 mm in height, 50 mm in width), and bubble behaviors were investigated experimentally. Bubble sizes, bubble rising velocities and void fractions were measured using void probes. Argon gas was injected through five nozzles of 4 mm in diameter into Pb-Bi at two locations. The experimental conditions are the pressure of atmospheric pressure, Pb-Bi temperatures of 443 K, and the flow rate of injection Ar gas is 10, 20, and 30 NL/min. The measured bubble rising velocities were distributed in the range from 1 to 3 m/s. The average velocity was about 0.6 m/s. The measured bubble chord lengths were distributed from 1 mm up to 30 mm. The average chord length was about 7 mm. An analysis was performed by two-dimensional and two-fluid model. The experimental results were compared with the analytical results to evaluate the validity of the analytical model. Although large diameter bubbles were observed in the experiment, the drag force model for spherical bubbles performed better for simulation of the experimental result because of high surface tension force of Pb-Bi. (authors)

Yumi Yamada [Advanced Reactor Technology Company, Ltd. (Japan); Toyou Akashi; Minoru Takahashi [Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)

2006-07-01T23:59:59.000Z

365

The Effect of Gas Absorption on the Scattered Radiation in the Solar Almucantar: Results of Numerical Simulation  

NLE Websites -- All DOE Office Websites (Extended Search)

Gas Absorption on the Gas Absorption on the Scattered Radiation in the Solar Almucantar: Results of Numerical Simulation T. Yu. Chesnokova, K. M. Firsov, I. M. Nasrtdinov, S. M. Sakerin, V. V. Veretennikov, and T. B. Zhuravleva Institute of Atmospheric Optics Tomsk, Russia Introduction The methods for reconstruction of the aerosol optical characteristics (e.g., aerosol size distribution, and single-scattering albedo) from diffuse and direct radiation measured in the solar almucantar has been widely used during the last decade. The photometers with filters in the "atmospheric transparency windows" in the wavelength range 0.4 to 1 m were applied for measurements. Usually it was assumed that one could neglect the molecular absorption of the measured diffuse radiation. Further development

366

Lateral migration of living cells in inertial microfluidic systems explored by fully three-dimensional numerical simulation  

E-Print Network (OSTI)

The effects of cell size and deformability on the lateral migration and deformation of living cells flowing through a rectangular microchannel has been numerically investigated and compared with the inertial-microfluidics data on detection and separation of cells. The results of this work indicate that the cells move closer to the centerline if they are bigger and/or more deformable and that their equilibrium position is largely determined by the solvent (cytosol) viscosity, which is much less than the polymer (cytoskeleton) viscosity measured in most rheological systems. Simulations also suggest that decreasing channel dimensions leads to larger differences in equilibrium position for particles of different viscoelastic properties, giving design guidance for the next generation of microfluidic cell separation chips.

Hongzhi Lan; Soojung Claire Hur; Dino Di Carlo; Damir B. Khismatullin

2013-06-19T23:59:59.000Z

367

Numerical Simulation of Hydrodynamics of a Heavy Liquid Drop Covered by Vapor Film in a Water Pool  

SciTech Connect

A numerical study on the hydrodynamics of a droplet covered by vapor film in water pool is carried out. Two level set functions are used as to implicitly capture the interfaces among three immiscible fluids (melt-drop, vapor and coolant). This approach leaves only one set of conservation equations for the three phases. A high-order Navier-Stokes solver, called Cubic-Interpolated Pseudo-Particle (CIP) algorithm, is employed in combination with level set approach, which allows large density ratios (up to 1000), surface tension and jump in viscosity. By this calculation, the hydrodynamic behavior of a melt droplet falling into a volatile coolant is simulated, which is of great significance to reveal the mechanism of steam explosion during a hypothetical severe reactor accident. (authors)

Ma, W.M.; Yang, Z.L.; Giri, A.; Sehgal, B.R. [Royal Institute of Technology (KTH), Drottning Kristinas vaeg 33 A, 100 44, Stockholm (Sweden)

2002-07-01T23:59:59.000Z

368

Numerical Simulation of Dust in a Cometary Coma: Application to Comet 67P/Churyumov-Gerasimenko  

Science Journals Connector (OSTI)

The Rosetta spacecraft is en route to comet 67P/Churyumov-Gerasimenko for a rendezvous, landing, and extensive orbital phase beginning in 2014. With a limited amount of available observational data, planning of the mission as well as the interpretation of measurements obtained by instruments on board the spacecraft requires modeling of the dusty/gas environment of the comet. During the mission, the collision regime in the inner coma will change starting from transitional to fully collisionless. As a result, a physically correct model has to be valid at conditions that are far from equilibrium and account for the kinetic nature of the processes occurring in the coma. A study of the multi-species coma of comet 67P/Churyumov-Gerasimenko is presented in our previous paper, where we describe our kinetic model and discuss the results of its application to cases that correspond to the different stages during the mission. In this work, we focus on numerical modeling of the dust phase in the coma of comet 67P/Churyumov-Gerasimenko and its interaction with the surrounding gas. The basic phenomena that govern the dynamics and energy balance of the dust grains are outlined. The effect of solar radiation pressure and the nucleus gravity in limiting the maximum liftable mass of the grains is discussed. The distribution of the terminal velocity of the dust grains as a function of subsolar angle is derived in the paper. We have found that in the regions with high gradients of the gas density, spike-like features can form in the dust flow. The obtained results represent the state of the coma in the vicinity of the nucleus for a series of stages throughout the Rosetta mission. The implications of the model results for future measurements by the GIADA instrument are discussed.

Valeriy Tenishev; Michael R. Combi; Martin Rubin

2011-01-01T23:59:59.000Z

369

Numerical simulation of fluid flow and heat transfer inside a rotating disk-cylinder configuration by a lattice Boltzmann model  

Science Journals Connector (OSTI)

A simple lattice Boltzmann model for numerical simulation of fluid flow and heat transfer inside a rotating disk-cylinder configuration, which is of fundamental interest and practical importance in science as well as in engineering, is proposed in this paper. Unlike existing lattice Boltzmann models for such flows, which were based on primitive-variable Navier-Stokes equations, the target macroscopic equations of the present model for the flow field are vorticitystream function equations, inspired by our recent work designed for nonrotating flows [S. Chen, J. Tlke, and M. Krafczyk, Phys. Rev. E 79, 016704 (2009); S. Chen, J. Tlke, S. Geller, and M. Krafczyk, Phys. Rev. E 78, 046703 (2008)]. The flow field and the temperature field both are solved by the D2Q5 model. Compared with the previous models, the present model is more efficient, more stable, and much simpler. It was found that, even though with a relatively low grid resolution, the present model can still work well when the Grashof number is very high. The advantages of the present model are validated by numerical experiments.

Sheng Chen; Jonas Tlke; Manfred Krafczyk

2009-07-14T23:59:59.000Z

370

Direct numerical simulation of ignition front propagation in a constant volume with temperature inhomogeneities. I. Fundamental analysis and diagnostics  

SciTech Connect

The influence of thermal stratification on autoignition at constant volume and high pressure is studied by direct numerical simulation (DNS) with detailed hydrogen/air chemistry with a view to providing better understanding and modeling of combustion processes in homogeneous charge compression-ignition engines. Numerical diagnostics are developed to analyze the mode of combustion and the dependence of overall ignition progress on initial mixture conditions. The roles of dissipation of heat and mass are divided conceptually into transport within ignition fronts and passive scalar dissipation, which modifies the statistics of the preignition temperature field. Transport within ignition fronts is analyzed by monitoring the propagation speed of ignition fronts using the displacement speed of a scalar that tracks the location of maximum heat release rate. The prevalence of deflagrative versus spontaneous ignition front propagation is found to depend on the local temperature gradient, and may be identified by the ratio of the instantaneous front speed to the laminar deflagration speed. The significance of passive scalar mixing is examined using a mixing timescale based on enthalpy fluctuations. Finally, the predictions of the multizone modeling strategy are compared with the DNS, and the results are explained using the diagnostics developed. (author)

Chen, Jacqueline H.; Hawkes, Evatt R.; Sankaran, Ramanan [Reacting Flow Research Department, Combustion Research Facility, Sandia National Laboratories, P.O. Box 969 MS 9051, Livermore, CA 94551-0969 (United States); Mason, Scott D. [Lockheed Martin Corporation, Sunnyvale, CA 94089 (United States); Im, Hong G. [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109-2125 (United States)

2006-04-15T23:59:59.000Z

371

Influence of the power law index on the fiber breakage during injection molding by numerical simulations  

Science Journals Connector (OSTI)

In predictive engineering for polymer processes the proper prediction of material microstructure from known processing conditions and constituent material properties is a critical step forward properly predicting bulk properties in the finished composite. Operating within the context of long-fiber thermoplastics (LFT length > 15mm) this investigation concentrates on the influence of the power law index on the final fiber length distribution within the injection molded part. To realize this the Autodesk Simulation Moldflow Insight Scandium 2013 software has been used. In this software a fiber breakage algorithm is available from this release on. Using virtual material data with realistic viscosity levels allows to separate the influence of the power law index on the fiber breakage from the other material and process parameters. Applying standard settings for the fiber breakage parameters results in an obvious influence on the fiber length distribution through the thickness of the part and also as function of position in the part. Finally the influence of the shear rate constant within the fiber breakage model has been investigated illustrating the possibility to fit the virtual fiber length distribution to the possible experimentally available data.

Wim Six; Hilde Bonte; Eric Debrabandere

2013-01-01T23:59:59.000Z

372

Numerical simulation of preformed particle gel flooding for enhancing oil recovery  

Science Journals Connector (OSTI)

Abstract As a new type of oil recovery enhancing technology, preformed particle gel (PPG) flooding has been gradually used for high water-cut reservoir development. However, the current commercial software cannot simulate the processes of PPG flooding. In this paper, a novel mathematical model considering the behaviors of pore-throat plugging and particles restarting, the matching relations of particle size, throat size and pressure gradient is established based on the mass conservation equation and solved by IMPES and typical four-order RungeKutta methods. Also, the codes are written by Visual Basic, and the verification is proved by experimental data. Then, the influences of injection rate, suspension concentration, mean particle diameter, critical threshold pressure gradient and permeability ratio in ultimate oil recovery factor and water-cut are studied. The results show that, with the injection rate, mean particle diameter and critical restarting pressure gradient coefficient increasing, the ultimate oil recovery factor will increase first, and then decrease. As the concentration of injection suspension increases, the ultimate oil recovery factor will increase first, but at the later stage it tends to be smooth. As the permeability ratio increases, the enhanced recovery factor will also increase first, and then tend to be smooth.

Jing Wang; Huiqing Liu; Zenglin Wang; Jie Xu; Dengyu Yuan

2013-01-01T23:59:59.000Z

373

Numerical simulations of stick percolation: Application to the study of structured magnetorheologial elastomers  

E-Print Network (OSTI)

In this article we explore how structural parameters of composites filled with one-dimensional, electrically conducting elements (such as sticks, needles, chains, or rods) affect the percolation properties of the system. To this end, we perform Monte Carlo simulations of asymmetric two-dimensional stick systems with anisotropic alignments. We compute the percolation probability functions in the direction of preferential orientation of the percolating objects and in the orthogonal direction, as functions of the experimental structural parameters. Among these, we considered the average length of the sticks, the standard deviation of the length distribution, and the standard deviation of the angular distribution. We developed a computer algorithm capable of reproducing and verifying known theoretical results for isotropic networks and which allows us to go beyond and study anisotropic systems of experimental interest. Our research shows that the total electrical anisotropy, considered as a direct consequence of the percolation anisotropy, depends mainly on the standard deviation of the angular distribution and on the average length of the sticks. A conclusion of practical interest is that we find that there is a wide and well-defined range of values for the mentioned parameters for which it is possible to obtain reliable anisotropic percolation under relatively accessible experimental conditions when considering composites formed by dispersions of sticks, oriented in elastomeric matrices.

J. L. Mietta; R. M. Negri; P. I. Tamborenea

2014-05-04T23:59:59.000Z

374

Reconnection in orthogonally interacting vortex tubes: Direct numerical simulations and quantifications  

Science Journals Connector (OSTI)

The three?dimensional time evolution of two orthogonally offset cylindrical vortices of equal strength is simulated by solving the hyperviscosity?regularized incompressible NavierStokes equations. A Fourier pseudospectral method with a time?split integration scheme is used for the solution. Four runs with different Reynolds numbers ranging between 6902100 are performed each with a resolution of 963 collocation points. The sequence of important physical processes and the evolution of local and global quantities such as vorticity velocity and mean?square strain rate are presented. It is found that the growth rate of the maximum vorticity is at most exponential. The Reynolds number dependence of the time scale of reconnection the vorticity growth rate and the time at which the maximum vorticity is attained are examined and differences between the present results and Saffmans essentially two?dimensional model predictions are encountered and elucidated. The distributions of the eigenvalues ? ? ? and the corresponding eigenvectors s ? s ? s ? of the rate of strain tensor S i j are calculated at different times. It is found that as the mean?square strain rate ? increases during the evolution s ? and the vorticity vector ? are perfectly aligned and ?>0 in high ? regions. Strong temporal spatial and Reynolds number dependence of the strain fields is also seen. Evidence is presented that during reconnection the vorticity growth in newly forming bridges takes place in the vicinity of the upper stagnation line segment of the vortex dipole due to the nature of the vortex stretching term. Also examined is the initial finger formation and it is found that the initial nonuniform axial stretching and the displacement of the vortex cores due to a lift force play an important role in this process.

O. N. Boratav; R. B. Pelz; N. J. Zabusky

1992-01-01T23:59:59.000Z

375

Numerical simulation via parallel-distributed computing of energy absorption by metal deformation  

SciTech Connect

Collapsible steering column designs are credited with saving tens-of-thousands of lives since their introduction in the late 1960`s. The collapsible steering column is a safety feature designed to absorb energy and protect-the driver in a head-on collision. One of the most frequently used design concepts employs two telescoping metal tubes that slide over one another as the occupant impacts the steering wheel. Hardened steel ball bearings are embedded in a plastic sleeve located between the two tubes. There are two primary mechanisms for energy absorption during steering column collapse. One is the friction between the bearing and tube surfaces. Another is the gouging of the tubes` surfaces by the bearings. Current analytical models are unable to adequately capture the physics behind this process. In this paper we will present an overview of a parallel finite element code, currently under development, that can be used to simulate the highly nonlinear response of this energy absorbing mechanism. Our parallel algorithms are constructed on a message-passing foundation. The actual message-passing implementation used was the Argonne-developed p4 package. However, other message-passing libraries can easily be accommodated as they are largely identical in function and differ only in syntax. Once the algorithm is restructured as a set of processes communicating through messages, the program can run on systems as diverse as a uniprocessor workstation, multiprocessors with and without shared memory, a group of workstations that communicate over a local network, or any combination of the above. Benchmarks of the parallel code performance on networks of workstations and the IBM SP1 parallel supercomputer will be discussed.

Plaskacz, E.J.; Kulak, R.F.

1995-07-01T23:59:59.000Z

376

NONRESONANT INTERACTION OF CHARGED ENERGETIC PARTICLES WITH LOW-FREQUENCY NONCOMPRESSIVE TURBULENCE: NUMERICAL SIMULATION  

SciTech Connect

A new method for simulating the three-dimensional dynamics of charged energetic particles in very broadband noncompressive magnetic turbulence is introduced. All scales within the primary inertial range of the turbulence observed in the solar wind near 1 AU are now included for the independent computations of both the particle dynamics and the turbulent magnetic field lines (MFLs). While previous theories of resonant particle pitch-angle (PA) scattering and transport in interplanetary magnetic fields had favored interpreting the observed depletions in the electron PA distributions (PADs) around 90 Degree-Sign PA as evidence of poor scattering at low PA cosines, the computed particle dynamics reveal a very different reality. The MFL directions now vary on many scales, and the PADs are depleted around 90 Degree-Sign PA due to nonresonant filtering of the particles that propagate at too large an angle to the local magnetic field. Rather than being too weak, the scattering through 90 Degree-Sign PA is actually so strong that the particles (electrons and protons/ions) are reflected and trapped in the turbulent magnetic fields. While the low-frequency nonresonant turbulence produces ubiquitous magnetic traps that only let through particles with the most field-aligned velocities, higher-frequency near-gyroscale turbulence, when present, enhances particle transport by allowing the particles to navigate between magnetic traps. Finally, visualizing both particle trajectories and MFLs in the very same turbulence reveals a powerful tool for understanding the effects of the turbulent fields on the particle dynamics and cross-field transport. Some cross-field-line scattering, strongly amplified by MFL dispersal, results in a strong cross-field scattering of the particles. From this visualization, it also appears that near-gyroscale turbulence, previously known as gyroresonant turbulence, does not resonantly interact with the particles. The interaction between particles and fields at or near the gyroscale, though potentially strong, does not actually involve the periodic driving of a true resonance.

Ragot, B. R. [Helio Research, P.O. Box 1414, Nashua, NH 03061 (United States)

2012-10-20T23:59:59.000Z

377

Numerical simulations for the coal/oxidant distribution effects between two-stages for multi opposite burners (MOB) gasifier  

Science Journals Connector (OSTI)

Abstract A 3D CFD model for two-stage entrained flow dry feed coal gasifier with multi opposite burners (MOB) has been developed in this paper. At each stage two opposite nozzles are impinging whereas the two other opposite nozzles are slightly tangential. Various numerical simulations were carried out in standard CFD software to investigate the impacts of coal and oxidant distributions between the two stages of the gasifier. Chemical process was described by Finite Rate/Eddy Dissipation model. Heterogeneous and homogeneous reactions were defined using the published kinetic data and realizable k? turbulent model was used to solve the turbulence equations. Gassolid interaction was defined by EulerLagrangian frame work. Different reaction mechanism were investigated first for the validation of the model from published experimental results. Then further investigations were made through the validated model for important parameters like species concentrations in syngas, char conversion, maximum inside temperature and syngas exit temperature. The analysis of the results from various simulated cases shows that coal/oxidant distribution between the stages has great influence on the overall performance of gasifier. The maximum char conversion was found 99.79% with coal 60% and oxygen 50% of upper level of injection. The minimum char conversion was observed 95.45% at 30% coal with 40% oxygen at same level. In general with oxygen and coal above or equal to 50% of total at upper injection level has shown an optimized performance.

Imran Nazir Unar; Lijun Wang; Abdul Ghani Pathan; Rasool Bux Mahar; Rundong Li; M. Aslam Uqaili

2014-01-01T23:59:59.000Z

378

Numerical simulation of leakage from a geologic disposal reservoirfor CO2, with transitions between super- and sub-criticalconditions  

SciTech Connect

The critical point of CO2 is at temperature and pressureconditions of Tcrit = 31.04oC, Pcrit = 73.82 bar. At lower (subcritical)temperatures and/or pressures, CO2 can exist in two different phases, aliquid and a gaseous state, as well as in two-phase mixtures of thesestates. Disposal of CO2 into brine formations would be made atsupercritical pressures. However, CO2 escaping from the storage reservoirmay migrate upwards towards regions with lower temperatures andpressures, where CO2 would be in subcritical conditions. An assessment ofthe fate of leaking CO2 requires a capability to model not onlysupercritical but also subcritical CO2, as well as phase changes betweenliquid and gaseous CO2 in sub-critical conditions. We have developed amethodology for numerically simulating the behavior of water-CO2 mixturesin permeable media under conditions that may include liquid, gaseous, andsupercritical CO2. This has been applied to simulations of leakage from adeep storage reservoir in which a rising CO2 plume undergoes transitionsfrom supercritical to subcritical conditions. We find strong coolingeffects when liquid CO2 rises to elevations where it begins to boil andevolve a gaseous CO2 phase. A three-phase zone forms (aqueous - liquid -gas), which over time becomes several hundred meters thick as decreasingtemperatures permit liquid CO2 to advance to shallower elevations. Fluidmobilities are reduced in the three-phase region from phase interferenceeffects. This impedes CO2 upflow, causes the plume to spread outlaterally, and gives rise to dispersed CO2 discharge at the land surface.Our simulations suggest that temperatures along a CO2 leakage path maydecline to levels low enough so that solid water ice and CO2 hydratephases may be formed.

Pruess, Karsten

2003-04-13T23:59:59.000Z

379

Numerical simulations of thermomagnetic instability in high-Tc superconductors: Dependence on sweep rate and ambient temperature  

Science Journals Connector (OSTI)

We report the results of numerical simulations of flux jumps on the basis of dynamic process of thermomagnetic interaction to the nonisothermal and nonadiabatic high-Tc superconductors in the regime of thermally activated flux creep when an applied magnetic field is parallel to a slab of the high-Tc superconductors. The simulations for the samples of BiSrCaCuO show that the flux jumps may occur only in the region of low ambient temperature, which is dependent upon the heat contact, and the sweep rate is greater than a lower critical value of about 20G?s and lesser than a large one up to the order of 110T?s. It is found that the predictions of the first flux-jump field Bfj1 are quantitatively in good agreement with the existing experimental data, and the temperature jumps are observed in the superconductors, corresponding to each flux jump in the magnetization loop. When the field sweep rate exceeds the large critical value for the case of the superconductor at 4.2K, the phenomenon of experimental observations without flux jump is successfully predicted by the theoretical simulation, where the thermomagnetic interaction is smoothly circulated at a new dynamic equilibrium state in the temperature region of about 10.616.4K higher than the ambient one, which is mainly dependent on the tradeoff of speeds of the dissipation energy in the slab and the heat removed into the coolant. After that, the sensitivity of the thermomagnetic instability to the parameters, such as critical current density, heat conductivity, heat transfer coefficient, critical geometrical scale, etc. is also discussed.

You-He Zhou and Xiaobin Yang

2006-08-15T23:59:59.000Z

380

A.G.Ramm, Dynamical systems method (DSM) for nonlinear equations in Banach spaces, Communic. in Nonlinear Sci. and Numer. Simulation, 11,  

E-Print Network (OSTI)

A.G.Ramm, Dynamical systems method (DSM) for nonlinear equations in Banach spaces, Communic. in Nonlinear Sci. and Numer. Simulation, 11, N3, (2006), 306­310. 1 #12; Dynamical systems method (DSM, KS 66506­2602, USA ramm@math.ksu.edu http://www.math.ksu.edu/#ramm Abstract The DSM (dynamical

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

A.G.Ramm, Dynamical systems method (DSM) for nonlinear equations in Banach spaces, Communic. in Nonlinear Sci. and Numer. Simulation, 11,  

E-Print Network (OSTI)

488 A.G.Ramm, Dynamical systems method (DSM) for nonlinear equations in Banach spaces, Communic. in Nonlinear Sci. and Numer. Simulation, 11, N3, (2006), 306-310. 1 #12;Dynamical systems method (DSM, KS 66506-2602, USA ramm@math.ksu.edu http://www.math.ksu.edu/ ramm Abstract The DSM (dynamical

382

Introduction Uniform Estimates for Transmission Problems 3D Multiscaled Asymptotic Expansion Numerical Simulations Skin-Effect Description in Electromagnetism with a  

E-Print Network (OSTI)

Numerical Simulations Skin-Effect Description in Electromagnetism with a Scaled Asymptotic Expansion Gabriel.08.2009 V. P´eron Skin-Effect Description in Electromagnetism with a Scaled Asymptotic Expansion 1 / 32 and Electromagnetism MONIQUE DAUGE, ERWAN FAOU, VICTOR P ´ERON (2009) Asymptotic Behavior at High Conductivity of Skin

Paris-Sud XI, Université de

383

Numerical simulation of the 16-19 October 1994 southeast Texas heavy rain event: precipitation results and diagnosis of the lifting mechanism  

E-Print Network (OSTI)

the actual case. A numerical model simulation is conducted to evaluate the ability of the PSU/NCAR Mesoscale Model (MM5) to reproduce this complex event and to diagnose the mechanism for initiation. Using only operational surface and upper-air observations...

Petroski, Thomas John

2012-06-07T23:59:59.000Z

384

The instability of Long's stationary solution and the evolution toward severe downslope windstorm flow. Part I: Nested grid numerical simulations  

SciTech Connect

Through direct numerical simulation, the instability of Long's exact finite-amplitude steady-state solution to the problem of stratified flow over topography and the subsequent evolution towards severe downslope windstorm flow is investigated. The integrations are limited with Long's analytical solution and are calculated in a model domain that employs three levels of interactive grid nesting. In this manner, the resolution achieved is approximately a factor of 10 greater than that previously employed. As a result of this increased resolution, three distinct stages of windstorm development are explicitly identified. In the first, convection acts to neutralize the region of overturned isentropes. During the next stage, a large-amplitude stationary disturbance develops above the lee slope of the topography. In time, small-scale secondary shear instability develops in local regions of enhanced shear associated with flow perturbations caused by the large-amplitude disturbance. In the final stage of development, these modes of shear instability evolve to larger spatial scale and come to dominate the flow in the mature windstorm state. In our analysis, it is furthermore demonstrated that these stages of development can be qualitatively and, to some extent, quantitatively reproduced in a parallel flow extracted from a cross section through Long's solution if a horizontally localized forcing, designed to enhance the vertical shear in the background wind field, is imposed. 30 refs., 11 figs.

Scinocca, J.F.; Peltier, W.R. (Univ. of Toronto, Ontario (Canada))

1993-07-15T23:59:59.000Z

385

MODELING STATISTICAL PROPERTIES OF SOLAR ACTIVE REGIONS THROUGH DIRECT NUMERICAL SIMULATIONS OF 3D-MHD TURBULENCE  

SciTech Connect

Statistical properties of the Sun's photospheric turbulent magnetic field, especially those of the active regions (ARs), have been studied using the line-of-sight data from magnetograms taken by the Solar and Heliospheric Observatory and several other instruments. This includes structure functions and their exponents, flatness curves, and correlation functions. In these works, the dependence of structure function exponents ({zeta}{sub p}) of the order of the structure functions (p) was modeled using a non-intermittent K41 model. It is now well known that the ARs are highly turbulent and are associated with strong intermittent events. In this paper, we compare some of the observations from Abramenko et al. with the log-Poisson model used for modeling intermittent MHD turbulent flows. Next, we analyze the structure function data obtained from the direct numerical simulations (DNS) of homogeneous, incompressible 3D-MHD turbulence in three cases: sustained by forcing, freely decaying, and a flow initially driven and later allowed to decay (case 3). The respective DNS replicate the properties seen in the plots of {zeta}{sub p} against p of ARs. We also reproduce the trends and changes observed in intermittency in flatness and correlation functions of ARs. It is suggested from this analysis that an AR in the onset phase of a flare can be treated as a forced 3D-MHD turbulent system in its simplest form and that the flaring stage is representative of decaying 3D-MHD turbulence. It is also inferred that significant changes in intermittency from the initial onset phase of a flare to its final peak flaring phase are related to the time taken by the system to reach the initial onset phase.

Malapaka, Shiva Kumar; Mueller, Wolf-Christian [Max-Planck Institute for Plasma Physics, Boltzmannstrasse 2, D-85748 Garching bei Muenchen (Germany)

2013-09-01T23:59:59.000Z

386

SimHydro 2014:Modelling of rapid transitory flows,11-13 June 2014, Sophia Antipolis Marechal E., Khelladi S., Ravelet F., Delepierre-Massue O,. Bakir F Towards numerical simulation of snow showersin jet-engine fuel systems.  

E-Print Network (OSTI)

-engine fuel systems. TOWARDS NUMERICAL SIMULATION OF SNOW SHOWERS IN JET- ENGINE FUEL SYSTEMS Ewen MARECHAL1 investigations over past years. Jet engines fuel system components may sensitive to clogging. When a snow shower., Delepierre-Massue O,. Bakir F ­ Towards numerical simulation of snow showersin jet-engine fuel systems. Jet

Boyer, Edmond

387

Numerical simulations of the Macondo well blowout reveal strong control of oil flow by reservoir permeability and exsolution of gas  

E-Print Network (OSTI)

for estimates of the oil and gas flow rate from the Macondoteam and carried out oil and gas flow simulations using theoil-gas system. The flow of oil and gas was simulated using

Oldenburg, C.M.

2013-01-01T23:59:59.000Z

388

Study of mixture formation and early flame development in a research GDI (gasoline direct injection) engine through numerical simulation and UV-digital imaging  

Science Journals Connector (OSTI)

Abstract The analysis of the mixture formation and early combustion processes in a slightly lean burn gasoline direct injection (GDI) engine is performed by using experimental and numerical techniques. UVvisible natural emission digital imaging is applied in the optically accessible combustion chamber of a research engine. This is equipped with the four-valve head and the same injection system of a commercial turbocharged engine. Optical accessibility is obtained through a quartz window placed on the piston head. Numerical simulations are performed by means of a 3D model developed within the AVL FireTM environment, which exploits an in-house developed sub-model for simulating the spray dynamics. Tests are carried out using commercial gasoline. The cyclic variability of the engine is first analysed in order to properly define a reference average pressure cycle to be used for the validation of the numerical model. This last is then proved as being highly predictive as the start of injection is moved in the working cycle. The main effects of the injection and ignition timing on the characteristic flame development angles, namely on the flame initiation and propagation, are analysed. Flame initiation is visualised both numerically and experimentally.

M. Costa; L. Marchitto; S.S. Merola; U. Sorge

2014-01-01T23:59:59.000Z

389

A novel numerical strategy for the simulation of irregular nonlinear waves and their effects on the dynamic response of offshore wind turbines  

Science Journals Connector (OSTI)

We present a novel numerical procedure for the prediction of nonlinear hydrodynamic loads exerted on offshore wind turbines exposed to severe weather conditions. The main feature of the proposed procedure is the computational efficiency, which makes the numerical package suitable for design purposes when a large number of simulations are typically necessary. The small computational effort is due to (i) the use of a domain-decomposition strategy, that, according to the local wave steepness, requires the numerical solution of the nonlinear governing equations only on a limited number of reduced regions (sub-domains) of the whole spacetime domain, (ii) the choice of the particular numerical method for the spatial discretization of the governing equation for the water-wave problem. Within the potential flow assumption, the Laplace equation is solved by means of a higher-order boundary-element method (HOBEM). For the time evolution of the unsteady free-surface equations the 4th-order RungeKutta algorithm is adopted. The compound solver is successfully applied to simulate nonlinear waves up to overturning plunging breakers, that may cause severe impact loads on the wind turbine substructure. Emphasis is finally given to wind turbine exposed to realistic environmental conditions, where the proposed tool is shown to be capable of capturing important nonlinear effects not detected by the linear models routinely adopted in the design practice.

Enzo Marino; Claudio Lugni; Claudio Borri

2013-01-01T23:59:59.000Z

390

On the wind field in the Loisach valley Numerical simulation and comparison with the LOWEX III data  

Science Journals Connector (OSTI)

A three-dimensional nonhydrostatic model, forced by a surface energy budget, has been used to study thermally induced circulation in mountainous terrain. The numerical results were compared with observed wind ...

G. Gross

1990-01-01T23:59:59.000Z

391

3D numerical simulation on fluid flow and heat transfer characteristics in multistage heat exchanger with slit fins  

Science Journals Connector (OSTI)

In this paper, a numerical investigation is performed for three-stage heat exchangers with plain plate fins and slit ... are arranged in a staggered way, and heat conduction in fins is considered. In order ... av...

W. Q. Tao; Y. P. Cheng; T. S. Lee

2007-11-01T23:59:59.000Z

392

Experimental study and numerical simulation of ion cyclotron heating of a hydrogen plasma in the T-11M tokamak  

Science Journals Connector (OSTI)

Results are presented from investigations of the possibility of heating a hydrogen plasma at the fundamental harmonic of the ion cyclotron frequency in the T-11M tokamak. The ... . Results from numerical simulati...

N. B. Rodionov; . A. Azizov; A. G. Alekseev; A. M. Belov

2006-02-01T23:59:59.000Z

393

Numerical Modeling of Hydrate Formation in Sand Sediment Simulating Sub-Seabed CO2 Storage in the form of Gas Hydrate  

Science Journals Connector (OSTI)

Abstract Among several methods for CO2 capture and storage, we focus on CO2 sequestration in the form of gas hydrate under the seafloor, mainly for many sequestration sites offshore Japan and for little risk of CO2 leakage from the sediment. However, it is difficult to evaluate the precise storage potential and cost of this method due to the lack of the relevant information. Here, in order to do feasibility studies of this technique so as to make an effective storage method, we made a 3-dimentional gas water flow simulator with kinetic hydrate formation. The new design of CO2 hydrate formation in porous media under two-phase flow condition was implemented in this simulator, and unknown parameters in necessary mathematical models for gas-water flow in sand sediments were verified from the comparison between the results of the numerical simulations and the experimental measurements from the previous study.

Takuya Nakashima; Toru Sato; Masayuki Inui

2013-01-01T23:59:59.000Z

394

Numerical simulations of neutron star mergers as the central engines of short-period gamma-ray bursts  

E-Print Network (OSTI)

We present the results of fully three dimensional, post-Newtonian hydrodynamical simulations of the dynamical evolution of mergers between compact stellar remnants (neutron stars and black holes). Although the code is ...

Archibald, Richard Andrew

2009-01-01T23:59:59.000Z

395

2-dimensional numerical simulations for the wave-wake-body interactions around circular cylinders in motion near seabed  

E-Print Network (OSTI)

grid system. In this thesis, several flow configurations, such as stationary and oscillating cylinder, were studied in order to predict and to understand the hydrodynamic forces. The results from the different simulations were compared with available...

Tavassoli, Armin

1999-01-01T23:59:59.000Z

396

Numerical Simulation of the Meso-? Scale Structure and Evolution of the 1977 Johnstown Flood. Part I: Model Description and Verification  

Science Journals Connector (OSTI)

The Pennsylvania State University/NCAR mesoscale model, originally developed by Anthes and Warner, is modified to simulate the meso-? scale structure and evolution of convectively driven weather systems. The modifications include: (i) two-way ...

Da-Lin Zhang; J. Michael Fritsch

1986-09-01T23:59:59.000Z

397

Numerical Simulations of Island-Scale Airflow over Maui and the Maui Vortex under Summer Trade Wind Conditions  

Science Journals Connector (OSTI)

The fifth-generation Pennsylvania State UniversityNCAR Mesoscale Model (MM5) coupled with the Noah land surface model (LSM) is employed to simulate island-scale airflow and circulations over Maui County, Hawaii, under summer trade wind ...

DaNa L. Carlis; Yi-Leng Chen; Vernon R. Morris

2010-07-01T23:59:59.000Z

398

Development and verification of a numerical simulator to calculate the bottom hole flowing pressures in multiphase systems  

E-Print Network (OSTI)

A vast amount of research has been conducted on the subject of pressure drop in muldphase flow systems. The simulator developed for this research incorporates the Beggs and Brill model for pressure drop prediction with an equation of state...

Rasool, Syed Ahmed

1994-01-01T23:59:59.000Z

399

Stability of finite difference numerical simulations of acoustic logging-while-drilling with different perfectly matched layer schemes  

Science Journals Connector (OSTI)

In acoustic logging-while-drilling (ALWD) finite difference in time domain (FDTD) simulations, large drill collar occupies, most of the fluid-filled borehole and divides the borehole fluid into two thin fluid col...

Hua Wang; Guo Tao; Xue-Feng Shang; Xin-Ding Fang; Daniel R. Burns

2013-12-01T23:59:59.000Z

400

Numerical simulations of the Macondo well blowout reveal strong control of oil flow by reservoir permeability and exsolution of gas  

E-Print Network (OSTI)

simulation of reservoir depletion and oil flow from themodel included the oil reservoir and the well with a toppressures of the deep oil reservoir, to a two-phase oil-gas

Oldenburg, C.M.

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

NUMERICAL DETERMINATION AND TREATMENT OF CONVECTIVE HEAT TRANSFER COEFFICIENT IN THE COUPLED BUILDING ENERGY AND CFD SIMULATION  

E-Print Network (OSTI)

for the correct prediction of the convective heat. A finer grid resolution in CFD does not always lead to a more conservation equations of flow on these grid cells. As shown in Figure 1(a), CFD calculates convective heat1 NUMERICAL DETERMINATION AND TREATMENT OF CONVECTIVE HEAT TRANSFER COEFFICIENT IN THE COUPLED

Chen, Qingyan "Yan"

402

Numerical simulations of rubber networks at moderate to high tensile strains using a purely enthalpic force extension curve for individual chains  

SciTech Connect

We report the results of numerical simulations of random, three-dimensional, periodic, tetrafunctional networks in response to a volume-preserving tensile strain. For the intranode force, we use a polynomial fit to a purely enthalpic ab initio force extension curve for extended polyisoprene. The simulation includes a relaxation procedure to minimize the node forces and enforces chain rupture when the extension of a network chain reaches the ab initio rupture strain. For the reasonable assumption that the distribution of network chain lengths is Gaussian, we find that the calculated snap-back velocity, temperature increase due to chain ruptures and predicted tensile stress versus strain curve are consistent with experimental data in the moderate to high extension regime. Our results show that a perfect tetrafunctional polyisoprene network is extremely robust, capable of supporting tensile stresses at least a factor of 10 greater than what is observed experimentally.

Hanson, David Edward [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

403

Numerical simulation of dynamic response of a long-span bridge to assess its vulnerability to non-synoptic wind  

Science Journals Connector (OSTI)

Abstract Winds generated by non-synoptic events such as those from tornadoes, microbursts or gust fronts, that are non-stationary or transient in nature and extreme in magnitude, can cause major damage to flexible structures. In this paper, a time-domain method is used to simulate the response of a long-span bridge subject to winds generated by a particular type of non-synoptic wind phenomenon such as a microburst to assess the vulnerability of the bridge to such winds. The self-excited or motion-induced and buffeting or turbulence-induced wind loads on the structure were modeled and simulated by Rational Functions and buffeting indicial functions, respectively. Wind from a translating microburst was simulated using empirical relationships that were derived from measurements of a laboratory-simulated microburst and the bridge response calculated to compare it with those induced by an equivalent straight-line wind that is used for structural design. It is shown that microburst induced structural vibration could be larger or smaller than the vibration induced by straight-line wind of equivalent magnitude depending on the relative size of the microburst with respect to the bridge span.

Bochao Cao; Partha P. Sarkar

2015-01-01T23:59:59.000Z

404

Adaptive numerical simulation of turbulent premixed J. B. Bell, M. S. Day, A. S. Almgren, M. J. Lijewski and  

E-Print Network (OSTI)

to the simulation of a premixed turbulent hydrogen ame. Keywords: Projection methods, low Mach number ows literature on adaptive methods for modeling reacting ows. The reader is referred to Bennett and Smooke [1 production rate for species m due to chemical reactions. Also, #21; is the thermal conductivity, #28

405

Numerical Simulation of Squeeze Film Dampers and Study of the Effect of Central Groove on the Dynamic Pressure Distribution  

E-Print Network (OSTI)

. The behavior of dynamic pressure profiles at different operating conditions, and the effect of a central groove on dynamic pressure profiles were also studied. Simulation results of a 3D case which is similar to the one experimentally studied by Delgado were...

Boppa, Praneetha

2012-10-19T23:59:59.000Z

406

Three-dimensional numerical simulation of settling and resuspension of solids in storage tanks with air injection recirculators  

SciTech Connect

Transient three-dimensional finite-difference numerical modeling of flow with settling solids in a 3.7 x 10/sup 3/ m/sup 3/ tank was performed. The number-average diameter of the particles was 15..mu..m and nominal volumetric concentration was 24 percent. Using dilute suspension, concentration dependent viscosity, and settling velocity assumption, modeled air lift circulators were shown to be sufficient to maintain solids in suspension during normal operation. Resuspension of solids was also shown to be accomplished by impulsive circulator startup in the absence of particle agglomeration. Settling velocity was shown to be a dominant parameter under the assumptions made.

Eyler, L.L.

1984-01-01T23:59:59.000Z

407

INTERNATIONAL JOURNAL OF c 2006 Institute for Scientific NUMERICAL ANALYSIS AND MODELING Computing and Information  

E-Print Network (OSTI)

t = · (M v) - Iion(s, v), ds dt = F(s, v), (1) where v is the transmembrane potential, M is the (diagonal

Karlsen, Kenneth Hvistendahl

408

Investigation of HCCI Combustion of Diethyl Ether and Ethanol Mixtures Using Carbon 14 Tracing and Numerical Simulations  

SciTech Connect

Despite the rapid combustion typically experienced in Homogeneous Charge Compression Ignition (HCCI), components in fuel mixtures do not ignite in unison or burn equally. In our experiments and modeling of blends of diethyl ether (DEE) and ethanol (EtOH), the DEE led combustion and proceeded further toward completion, as indicated by {sup 14}C isotope tracing. A numerical model of HCCI combustion of DEE and EtOH mixtures supports the isotopic findings. Although both approaches lacked information on incompletely combusted intermediates plentiful in HCCI emissions, the numerical model and {sup 14}C tracing data agreed within the limitations of the single zone model. Despite the fact that DEE is more reactive than EtOH in HCCI engines, they are sufficiently similar that we did not observe a large elongation of energy release or significant reduction in inlet temperature required for light-off, both desired effects for the combustion event. This finding suggests that, in general, HCCI combustion of fuel blends may have preferential combustion of some of the blend components.

Mack, J H; Dibble, R W; Buchholz, B A; Flowers, D L

2004-01-16T23:59:59.000Z

409

Modeling pure methane hydrate dissociation using a numerical simulator from a novel combination of X-ray computed tomography and macroscopic data  

SciTech Connect

The numerical simulator TOUGH+HYDRATE (T+H) was used to predict the transient pure methane hydrate (no sediment) dissociation data. X-ray computed tomography (CT) was used to visualize the methane hydrate formation and dissociation processes. A methane hydrate sample was formed from granular ice in a cylindrical vessel, and slow depressurization combined with thermal stimulation was applied to dissociate the hydrate sample. CT images showed that the water produced from the hydrate dissociation accumulated at the bottom of the vessel and increased the hydrate dissociation rate there. CT images were obtained during hydrate dissociation to confirm the radial dissociation of the hydrate sample. This radial dissociation process has implications for dissociation of hydrates in pipelines, suggesting lower dissociation times than for longitudinal dissociation. These observations were also confirmed by the numerical simulator predictions, which were in good agreement with the measured thermal data during hydrate dissociation. System pressure and sample temperature measured at the sample center followed the CH{sub 4} hydrate L{sub w}+H+V equilibrium line during hydrate dissociation. The predicted cumulative methane gas production was within 5% of the measured data. Thus, this study validated our simulation approach and assumptions, which include stationary pure methane hydrate-skeleton, equilibrium hydrate-dissociation and heat- and mass-transfer in predicting hydrate dissociation in the absence of sediments. It should be noted that the application of T+H for the pure methane hydrate system (no sediment) is outside the general applicability limits of T+H.

Gupta, A.; Moridis, G.J.; Kneafsey, T.J.; Sloan, Jr., E.D.

2009-08-15T23:59:59.000Z

410

NUMERICAL SIMULATION OF THREE-DIMENSIONAL ASYMMETRIC RECONNECTION AND APPLICATION TO A PHYSICAL MECHANISM OF PENUMBRAL MICROJETS  

SciTech Connect

Three-dimensional (3D) component reconnection, where reconnecting field lines are not perfectly anti-parallel, is studied with a 3D magnetohydrodynamic simulation. In particular, we consider the asymmetry of the field strength of the reconnecting field lines. As the asymmetry increases, the generated reconnection jet tends to be parallel to stronger field lines. This is because weaker field lines have higher gas pressure in the initial equilibrium, and hence the gas pressure gradient along the reconnected field lines is generated, which accelerates the field-aligned plasma flow. This mechanism may explain penumbral microjets and other types of jets that are parallel to magnetic field lines.

Nakamura, Naoki [Division of Physics and Astronomy, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan); Shibata, Kazunari [Kwaan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Isobe, Hiroaki, E-mail: nakamura@kwasan.kyoto-u.ac.jp, E-mail: shibata@kwasan.kyoto-u.ac.jp, E-mail: isobe@kwasan.kyoto-u.ac.jp [Unit of Synergetic Studies for Space, Kyoto University, Yamashina, Kyoto 607-8471 (Japan)

2012-12-20T23:59:59.000Z

411

TURBULENT MIXING AND LAYER FORMATION IN DOUBLE-DIFFUSIVE CONVECTION: THREE-DIMENSIONAL NUMERICAL SIMULATIONS AND THEORY  

SciTech Connect

Double-diffusive convection, often referred to as semi-convection in astrophysics, occurs in thermally and compositionally stratified systems which are stable according to the Ledoux criterion but unstable according to the Schwarzschild criterion. This process has been given relatively little attention so far, and its properties remain poorly constrained. In this paper, we present and analyze a set of three-dimensional simulations of this phenomenon in a Cartesian domain under the Boussinesq approximation. We find that in some cases the double-diffusive convection saturates into a state of homogeneous turbulence, but with turbulent fluxes several orders of magnitude smaller than those expected from direct overturning convection. In other cases, the system rapidly and spontaneously develops closely packed thermo-compositional layers, which later successively merge until a single layer is left. We compare the output of our simulations with an existing theory of layer formation in the oceanographic context and find very good agreement between the model and our results. The thermal and compositional mixing rates increase significantly during layer formation and increase even further with each merger. We find that the heat flux through the staircase is a simple function of the layer height. We conclude by proposing a new approach to studying transport by double-diffusive convection in astrophysics.

Rosenblum, E. [Department of Physics, Stony Brook University, Stony Brook, New York, NY 11794 (United States); Garaud, P.; Traxler, A. [Department of Applied Mathematics and Statistics, Baskin School of Engineering, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Stellmach, S. [Institut fuer Geophysik, Westfaelische Wilhelms-Universitaet Muenster, Muenster D-48149 (Germany)

2011-04-10T23:59:59.000Z

412

Numerical simulations for high efficiency HIT solar cells using microcrystalline silicon as emitter and back surface field (BSF) layers  

Science Journals Connector (OSTI)

Abstract In present article the influence of thickness and band gap of microcrystalline silicon emitter layer, amorphous silicon front and back intrinsic layers and p-type crystalline silicon (c-Si) wafer thickness on the performance of TCO/?c-Si:H(n)/a-Si:H(i)/c-Si(p)/a-Si:H(i)/?c-Si:H(p+)/Ag Heterojunction with thin intrinsic layer (HIT) solar cell along with other structural possibilities were investigated through computer simulations using AFORS-HET software. These simulations revealed the importance of inclusion of intrinsic a-Si:H thin layer in improving the performance of solar cell with the help of interface passivation. Also microcrystalline BSF can raise the conversion efficiency more than 4% compared to HIT solar cell having no BSF layer. Highest stable efficiency of 24.12% for p-type substrate based HITBSF (HIT with back surface field) solar cells was observed. Furthermore the effect of textured transparent conductive oxide (TCO) on solar cells was investigated where the enhanced light trapping was observed with the use of textured TCO surface which raised the performance of solar cells. These optimizations may help in fabricating ?c-Si emitter and BSF based HIT solar cells with stable efficiencies compared to possibly degraded efficiencies as in case of a-Si:H based HIT solar cell structures studied so far.

Arti Rawat; Mansi Sharma; Deepika Chaudhary; S. Sudhakar; Sushil Kumar

2014-01-01T23:59:59.000Z

413

Numerical simulations of particle growth in a silicon-CVD fluidized bed reactor via a CFDPBM coupled model  

Science Journals Connector (OSTI)

Abstract A EulerianEulerian two-fluid model coupled with population balance equations was applied to simulate the evolution of silicon particle growth by chemical vapor deposition of silane pyrolysis in a three-dimensional slugging fluidized bed reactor using FLUENT. The simulation of the particle growth considering surface deposition, cluster scavenging, aggregation and wall deposition was carried out after the verification of flow and heat transfer characteristics based on the well-accepted correlations. The results showed that the scavenging effect was responsible for the particle growth, and the growth rate agreed well with the experimental data by Tejero-Ezpeleta et al. (2004) when the scavenging factor was set to 0.1 under the condition of 923K and atmospheric pressure. Moreover, the formation of light silicon hydrides by silane homogeneous pyrolysis in the dilute phase was also investigated in the form of CHMEKIN mechanism, which showed that disilane turned to be the main silicon hydride and the silane conversion was underestimated by 12.5%. Finally, the effects of operating conditions on the growth rate were studied in detail with the observation of defluidization phenomenon during the evolution of particle growth.

Si-Si Liu; Wen-De Xiao

2014-01-01T23:59:59.000Z

414

Exploiting Active Subspaces to Quantify Uncertainty in the Numerical Simulation of the HyShot II Scramjet  

E-Print Network (OSTI)

We present a computational analysis of the reactive flow in a hypersonic scramjet engine with emphasis on effects of uncertainties in the operating conditions. We employ a novel methodology based on active subspaces to characterize the effects of the input uncertainty on the scramjet performance. The active subspace re-parameterizes the operating conditions from seven well characterized physical parameters to a single derived active variable. This dimension reduction enables otherwise intractable---given the cost of the simulation---computational studies to quantify uncertainty; bootstrapping provides confidence intervals on the studies' results. In particular we (i) identify the parameters that contribute the most to the variation in the output quantity of interest, (ii) compute a global upper and lower bound on the quantity of interest, and (iii) classify sets of operating conditions as safe or unsafe corresponding to a threshold on the output quantity of interest. We repeat this analysis for two values of ...

Constantine, Paul; Larsson, Johan; Iaccarino, Gianluca

2014-01-01T23:59:59.000Z

415

Numerical Simulation on the Performance of a Combination of External and Cavity Absorber for Solar Power Plant  

Science Journals Connector (OSTI)

Abstract Optical and thermal simulation of a new up-down arranged dual-receiver for solar tower plant is presented in this paper. The top receiver is an external absorber type to serve as the boiling section, the bottom receiver is a cavity type to serve as the superheating section. The heliostat field is divided into two parts respectively for boiling and superheating section, it is quick and simple to control the heat flux distribution on both section. Then multi-aiming strategy is used for avoiding appearance of heat spot. For cavity receiver, a optimized layout for tubes is to increase convective heat transfer coefficient in the high heat flux religions. The concept of this new receiver is illustrated by a 10 \\{MWe\\} solar power plant that produces main steam at 513.5C and pressure of 10.12MPa. Finally, this dual-receiver has a thermal efficiency of 91%.

Y Luo; X.Z. Du; L.J. Yang; Y.P. Yang

2014-01-01T23:59:59.000Z

416

Numerical simulation study of silica and calcite dissolution around a geothermal well by injecting high pH solutions with chelating agent.  

SciTech Connect

Dissolution of silica, silicate, and calcite minerals in the presence of a chelating agent (NTA) at a high pH has been successfully performed in the laboratory using a high-temperature flow reactor. The mineral dissolution and porosity enhancement in the laboratory experiment has been reproduced by reactive transport simulation using TOUGHREACT. The chemical stimulation method has been applied by numerical modeling to a field geothermal injection well system, to investigate its effectiveness. Parameters from the quartz monzodiorite unit at the Enhanced Geothermal System (EGS) site at Desert Peak (Nevada) were used. Results indicate that the injection of a high pH chelating solution results in dissolution of both calcite and plagioclase minerals, and avoids precipitation of calcite at high temperature conditions. Consequently reservoir porosity and permeability can be enhanced especially near the injection well.

Xu, Tianfu; Rose, Peter; Fayer, Scott; Pruess, Karsten

2009-02-01T23:59:59.000Z

417

Generalization of the Atkinson-Wilcox Theorem and the Development of a Novel Scaled Boundary Finite Element Formulation for the Numerical Simulation of Electromagnetic Radiation  

E-Print Network (OSTI)

The Scaled Boundary Finite Element Method is a novel semi-analytical method jointly developed by Chongmin Song and John P Wolf to solve problems in elastodynamics and allied problems in civil engineering. This novel method has been recently reformulated for the following categories of problems in electromagnetics: (1) Determination of Eigen values of metallic cavity structures, 2) Full wave analysis of Shielded micro-strip transmission line structures, and Very Large Scale Integrated Circuit (VLSI) interconnects, and 3) Full wave analysis of periodic structures. In this paper, a novel Scaled Boundary Finite Element formulation is developed for the numerical simulation of the time harmonic electromagnetic radiation in free space from metallic structures of arbitrary shape. The development of the novel formulation necessitates the generalization of the familiar Atkinson-Wilcox radiation series expansion so as to be applicable for arbitrary boundary circumscribing the source of radiation.

Rajan, V S P

2006-01-01T23:59:59.000Z

418

Numerical Simulation of Single- and Dual-media Thermocline Tanks for Energy Storage in Concentrating Solar Power Plants  

Science Journals Connector (OSTI)

Abstract A single molten-salt thermocline tank is a low-cost alternative to conventional multiple-tank systems for concentrating solar power thermal energy storage. Thermocline tanks are typically composed of molten salt and a filler material that provides sensible heat capacity at reduced cost; such tanks are referred to as a dual-media thermocline (DMT). However, inclusion of quartzite rock filler introduces the potential for mechanical ratcheting of the tank wall during thermal cycling. To avoid this potential thermomechanical mode of failure, the tank can be operated solely with molten salt, as a single-medium thermocline (SMT) tank. In the absence of a filler material to suppress formation of tank-scale convection eddies, the SMT tank may exhibit undesirable internal fluid flows in the tank cross-section. The performance of DMT and SMT tanks is compared under cyclic operation, assuming adiabatic external wall boundary conditions. A computational fluid dynamics model is used to solve for the spatial temperature and velocity distributions within the tank. For the DMT tank, a two-temperature model is used to account for the non-thermal equilibrium between the molten salt and the filler material, and Forchheimer's extension of Darcy's Law is added to the porous-medium formulation of the laminar momentum equation. The governing equations are solved numerically using a finite volume approach. For adiabatic external boundaries, the SMT tank yields a percentage point increase in the first and second law efficiencies relative to the DMT tank. Future work is needed to compare the thermocline tank designs with respect to capital cost and storage performance under non-adiabatic wall boundaries.

C. Mira-Hernndez; S.M. Flueckiger; S.V. Garimella

2014-01-01T23:59:59.000Z

419

Validation Studies for Numerical Simulations of Flow Phenomena Expected in the Lower Plenum of a Prismatic VHTR Reference Design  

SciTech Connect

The final design of the very high temperature reactor (VHTR) of the fourth generation of nuclear power plants (Gen IV) has not yet been established. The VHTR may be either a prismatic (block) or pebble bed type. It may be either gas-cooled or cooled with an as yet unspecified molten salt. However, a conceptual design of a gas-cooled VHTR, based on the General Atomics GT-MHR, does exist and is called the prismatic VHTR reference design, MacDonald et al [2003], General Atomics [1996]. The present validation studies are based on the prismatic VHTR reference design. In the prismatic VHTR reference design, the flow in the lower plenum will be introduced by dozens of turbulent jets issuing into a large crossflow that must negotiate dozens of cylindrical support columns as it flows toward the exit duct of the reactor vessel. The jets will not all be at the same temperature due to the radial variation of power density expected in the core. However, it is important that the coolant be well mixed when it enters the power conversion unit to ensure proper operation and long life of the power conversion machinery. Hence, it is deemed important to be able to accurately model the flow and mixing of the variable temperature coolant in the lower plenum and exit duct. Accurate flow modeling involves determining modeling strategies including the fineness of the grid needed, iterative convergence tolerance, numerical discretization method used, whether the flow is steady or unsteady, and the turbulence model and wall treatment employed. It also involves validation of the computer code and turbulence model against a series of separate and combined flow phenomena and selection of the data used for the validation. The present report describes progress made to date for the task entitled CFD software validation of jets in crossflow which was designed to investigate the issues pertaining to the validation process.

Richard W. Johnson

2005-09-01T23:59:59.000Z

420

A Transient Numerical Simulation of Perched Ground-Water Flow at the Test Reactor Area, Idaho National Engineering and Environmental Laboratory, Idaho, 1952-94  

SciTech Connect

Studies of flow through the unsaturated zone and perched ground-water zones above the Snake River Plain aquifer are part of the overall assessment of ground-water flow and determination of the fate and transport of contaminants in the subsurface at the Idaho National Engineering and Environmental Laboratory (INEEL). These studies include definition of the hydrologic controls on the formation of perched ground-water zones and description of the transport and fate of wastewater constituents as they moved through the unsaturated zone. The definition of hydrologic controls requires stratigraphic correlation of basalt flows and sedimentary interbeds within the saturated zone, analysis of hydraulic properties of unsaturated-zone rocks, numerical modeling of the formation of perched ground-water zones, and batch and column experiments to determine rock-water geochemical processes. This report describes the development of a transient numerical simulation that was used to evaluate a conceptual model of flow through perched ground-water zones beneath wastewater infiltration ponds at the Test Reactor Area (TRA).

B. R. Orr (USGS)

1999-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

3-D Numerical Simulation of Heat Transfer and Turbulent Flow in a Receiver Tube of Solar Parabolic Trough Concentrator with Louvered Twisted-tape Inserts  

Science Journals Connector (OSTI)

Abstract High temperature and higher-thermal efficiency for CSP cycles are main goals to improve trough collector's technologies. For a parabolic trough collector the major factor for optimum heat transfer from sun to the heat transfer fluid passing in the absorber tube is to have high convection heat transfer coefficient. Literature shows that absorber tubes with various tape inserts are used and recommended to produce high convection coefficient. Typical twisted-tape (TT) enhances heat exchange between tube surface and working fluid by generating turbulent swirling flow. In this study, enhancement of convection coefficient in the receiver tube of a solar parabolic trough concentrator that the absorber tube is equipped with a new perforated louvered twisted- tape (LTT) is studied numerically. For numerical simulations three different twist ratios (TR), TR=y/W= 2.67, 4, 5.33 (y is the length required for one twist and W is the width of the tape) are used in an experimental laboratory trough collector. Flow is assumed turbulent due to louvered perforated surface and rotational shape of the tape. For thermal boundary condition, non- uniform wall solar heat flux is determined by Soltrace code on the outer surface of the absorber tube. Heat transfer rate and pressure drop are determined for fully developed condition for several Reynolds numbers based on the tube diameter and flow mean velocity. Results show that the heat transfer coefficient and pressure drop increase significantly in comparison with a typical plain twisted-tape in the tube and a plain tube.

Sh. Ghadirijafarbeigloo; A.H. Zamzamian; M. Yaghoubi

2014-01-01T23:59:59.000Z

422

Numerical simulation of dual frequency etching reactors: Influence of the external process parameters on the plasma characteristics  

SciTech Connect

A one-dimensional particle-in-cell/Monte Carlo model is used to investigate Ar/CF{sub 4}/N{sub 2} discharges sustained in capacitively coupled dual frequency reactors, with special emphasis on the influence of the reactor parameters such as applied voltage amplitudes and frequencies of the two voltage sources. The presented calculation results include plasma density, ion current, average sheath potential and width, electron and ion average energies and energy distributions, and ionization rates. The simulations were carried out for high frequencies (HFs) of 27, 40, 60, and 100 MHz and a low frequency (LF) of 1 or 2 MHz, varying the LF voltage and keeping the HF voltage constant and vice versa. It is observed that the decoupling of the two sources is possible by increasing the applied HF to very high values (above 60 MHz) and it is not defined by the frequency ratio. Both voltage sources have influence on the plasma characteristics at a HF of 27 MHz and to some extent at 40 MHz. At HFs of 60 and 100 MHz, the plasma density and ion flux are determined only by the HF voltage source. The ion energy increases and the ion energy distribution function (IEDF) becomes broader with HF or LF voltage amplitude, when the other voltage is kept constant. The IEDF is broader with the increase of HF or the decrease of LF.

Georgieva, V.; Bogaerts, A. [Plasma, Laser Ablation and Surface Modeling ANTwerp (PLASMANT), Department of Chemistry, University of Antwerp, Campus Drie Eiken (CDE), Universiteitsplein 1, B-2610 Wilrijk-Antwerp (Belgium)

2005-07-15T23:59:59.000Z

423

Developments in Petroleum Science, 6 FUNDAMENTALS OF NUMERICAL  

E-Print Network (OSTI)

Developments in Petroleum Science, 6 FUNDAMENTALS OF NUMERICAL RESERVOIR SIMULATION DONALD WCongressCatalogingin PublicationData Peaceman, Donald W Fundamentals of numerical reservoir simulation. (develrpents in petroleum

Santos, Juan

424

Momentum flow in black-hole binaries. II. Numerical simulations of equal-mass, head-on mergers with antiparallel spins  

SciTech Connect

Research on extracting science from binary-black-hole (BBH) simulations has often adopted a 'scattering matrix' perspective: given the binary's initial parameters, what are the final hole's parameters and the emitted gravitational waveform? In contrast, we are using BBH simulations to explore the nonlinear dynamics of curved spacetime. Focusing on the head-on plunge, merger, and ringdown of a BBH with transverse, antiparallel spins, we explore numerically the momentum flow between the holes and the surrounding spacetime. We use the Landau-Lifshitz field-theory-in-flat-spacetime formulation of general relativity to define and compute the density of field energy and field momentum outside horizons and the energy and momentum contained within horizons, and we define the effective velocity of each apparent and event horizon as the ratio of its enclosed momentum to its enclosed mass-energy. We find surprisingly good agreement between the horizons' effective and coordinate velocities. During the plunge, the holes experience a frame-dragging-induced acceleration orthogonal to the plane of their spins and their infall ('downward'), and they reach downward speeds of order 1000 km/s. When the common apparent horizon forms (and when the event horizons merge and their merged neck expands), the horizon swallows upward field momentum that resided between the holes, causing the merged hole to accelerate in the opposite ('upward') direction. As the merged hole and the field energy and momentum settle down, a pulsational burst of gravitational waves is emitted, and the merged hole has a final effective velocity of about 20 km/s upward, which agrees with the recoil velocity obtained by measuring the linear momentum carried to infinity by the emitted gravitational radiation. To investigate the gauge dependence of our results, we compare generalized harmonic and Baumgarte-Shapiro-Shibata-Nakamura-moving-puncture evolutions of physically similar initial data; although the generalized harmonic and Baumgarte-Shapiro-Shibata-Nakamura-moving-puncture simulations use different gauge conditions, we find remarkably good agreement for our results in these two cases. We also compare our simulations with the post-Newtonian trajectories and near-field energy-momentum.

Lovelace, Geoffrey [Center for Radiophysics and Space Research, Cornell University, Ithaca, New York, 14853 (United States); Chen Yanbei; Cohen, Michael; Kaplan, Jeffrey D.; Keppel, Drew; Matthews, Keith D.; Nichols, David A.; Scheel, Mark A.; Sperhake, Ulrich [Theoretical Astrophysics 350-17, California Institute of Technology, Pasadena, California 91125 (United States)

2010-09-15T23:59:59.000Z

425

Numerical Simulations of Bouncing Jets  

E-Print Network (OSTI)

downhill gliding of the pool, at about 4mm/s of pool surface velocity. . . . . . . . . . . . . . . . . . . . . . 87 viii 5.7 Overall view of the shampoo jet bouncing of an inclined pool of the same liquid. The white arrow points at he breakup of the air....4 Time discretization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 3.5 Entropy residual stabilization . . . . . . . . . . . . . . . . . . . . . . 58 3.6 Adaptive mesh refinement . . . . . . . . . . . . . . . . . . . . . . . . 61 iv 3.7...

Lee, Sanghyun

2014-07-18T23:59:59.000Z

426

Numerical Simulation of Transpiration Cooling  

E-Print Network (OSTI)

University, Templergraben 55, 52056 Aachen SUMMARY Transpiration cooling using ceramic matrix composite (CMC

427

Numerical simulation of CO2 leakage from a geologic disposal reservoir including transitions from super- to sub-critical conditions, and boiling of liquid of CO2  

SciTech Connect

The critical point of CO{sub 2} is at temperature and pressure conditions of T{sub crit} = 31.04 C, P{sub crit} = 73.82 bar. At lower (subcritical) temperatures and/or pressures, CO{sub 2} can exist in two different phase states, a liquid and a gaseous state, as well as in two-phase mixtures of these states. Disposal of CO{sub 2} into brine formations would be made at supercritical pressures. However, CO{sub 2} escaping from the storage reservoir may migrate upwards towards regions with lower temperatures and pressures, where CO{sub 2} would be in subcritical conditions. An assessment of the fate of leaking CO{sub 2} requires a capability to model not only supercritical but also subcritical CO{sub 2}, as well as phase changes between liquid and gaseous CO{sub 2} in sub-critical conditions. We have developed a methodology for numerically simulating the behavior of water-CO{sub 2} mixtures in permeable media under conditions that may include liquid, gaseous, and supercritical CO{sub 2}. This has been applied to simulations of leakage from a deep storage reservoir in which a rising CO{sub 2} plume undergoes transitions from supercritical to subcritical conditions. We find strong cooling effects when liquid CO{sub 2} rises to elevations where it begins to boil and evolve a gaseous CO{sub 2} phase. A three-phase zone forms (aqueous - liquid - gas), which over time becomes several hundred meters thick as decreasing temperatures permit liquid CO{sub 2} to advance to shallower elevations. Fluid mobilities are reduced in the three-phase region from phase interference effects. This impedes CO{sub 2} upflow, causes the plume to spread out laterally, and gives rise to dispersed CO{sub 2} discharge at the land surface. Our simulation suggests that temperatures along a CO{sub 2} leakage path may decline to levels low enough so that solid water ice and CO{sub 2} hydrate phases may be formed.

Pruess, Karsten

2003-03-31T23:59:59.000Z

428

Numerical Simulation of the Meso-? Scale Structure and Evolution of the 1977 Johnstown Flood. Part II: Inertially Stable Warm-Core Vortex and the Mesoscale Convective Complex  

Science Journals Connector (OSTI)

A mesoscale warm-core vortex associated with the mesoscale convective complex (MCC) that produced the 1977 Johnstown flood is examined using a three-dimensional nested-grid model simulation of the flood episode. In the simulation, the vortex ...

Da-Lin Zhang; J. Michael Fritsch

1987-09-01T23:59:59.000Z

429

Numerical Simulations of Lightning and Storm Charge of the 2930 May 2004 Geary, Oklahoma, Supercell Thunderstorm Using EnKF Mobile Radar Data Assimilation  

Science Journals Connector (OSTI)

Results from simulations are compared with dual-Doppler and total lightning observations of the 2930 May 2004 high-precipitation supercell storm from the Thunderstorm Electrification and Lightning Experiment (TELEX). The simulations use two-...

Kristin M. Calhoun; Edward R. Mansell; Donald R. MacGorman; David C. Dowell

2014-11-01T23:59:59.000Z

430

A Theoretical Study on the Spontaneous Radiation of Inertia-gravity Waves Using the Renormalization Group Method. Part II: Verification of the Theoretical Equations by Numerical Simulation  

Science Journals Connector (OSTI)

The renormalization group equations (RGEs) describing spontaneous inertia-gravity wave (GW) radiation from part of a balanced flow through a quasi-resonance that were derived in a companion paper by Yasuda et al. are validated through numerical ...

Yuki Yasuda; Kaoru Sato; Norihiko Sugimoto

431

Numerical Simulation of Flow Field Inside a Squeeze Film Damper and the Study of the Effect of Cavitation on the Pressure Distribution  

E-Print Network (OSTI)

of SFDs can be expensive and time consuming. The current work simulates the flow field inside the dynamically deforming annular gap of a SFD using the commercial computational fluid dynamics (CFD) code Fluent and compares the results to the experimental...

Khandare, Milind Nandkumar

2012-02-14T23:59:59.000Z

432

Study of the comprehensive risk analysis of dam-break flooding based on the numerical simulation of flood routing. Part I: model development  

Science Journals Connector (OSTI)

Dam-break floods have been of increasing concern to safety ... of complex terrain in inundation areas multiplies the simulation difficulty of flood routing. In previous studies, representing the flood routing par...

Ruirui Sun; Xiaoling Wang; Zhengyin Zhou; Xuefei Ao; Xiaopei Sun

2014-09-01T23:59:59.000Z

433

Numerical Simulation of the Mesa-? Scale Structure and Evolution of the 1977 Johnstown Flood. Part III. Internal Gravity Waves and the Squall Line  

Science Journals Connector (OSTI)

The interaction between internal gravity waves and a squall line that developed early in the evolution of the 1977 Johnston flood event is studied based on available surface observations and a three-dimensional model simulation of the flood-...

Da-Lin Zhang; J. Michael Fritsch

1988-04-01T23:59:59.000Z

434

Numerical Simulation and Laboratory Testing of Time-Frequency MUSIC Beamforming for Identifying Continuous and Impulsive Ground Targets from a Mobile Aerial Platform  

E-Print Network (OSTI)

Hz sine source, a banded white noise source between 700-800 Hz, and a composite source combined simultaneously with both the sine and banded white noise sources. The proposed algorithm accurately estimates the simulated monopoles location...

Silva, Ramon Alejandro

2013-04-25T23:59:59.000Z

435

Numerical Investigations of Magnetohydrodynamic Hypersonic Flows.  

E-Print Network (OSTI)

??Numerical simulations of magnetohydrodynamic (MHD) hypersonic flow are presented for both laminar and turbulent flow over a cylinder and flow entering a scramjet inlet. ANSYS (more)

Guarendi, Andrew N

2013-01-01T23:59:59.000Z

436

Numerical Modeling | Open Energy Information  

Open Energy Info (EERE)

Numerical Modeling Numerical Modeling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Numerical Modeling Details Activities (8) Areas (2) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Data and Modeling Techniques Exploration Sub Group: Modeling Techniques Parent Exploration Technique: Modeling Techniques Information Provided by Technique Lithology: Stratigraphic/Structural: Stress fields and magnitudes Hydrological: Visualization and prediction of the flow patterns and characteristics of geothermal fluids Thermal: Thermal conduction and convection patterns in the subsurface Dictionary.png Numerical Modeling: A computer model that is designed to simulate and reproduce the mechanisms of a particular system. Other definitions:Wikipedia Reegle

437

Numerical Simulation of the Flow Field in 3D Eccentric Annular and 2D Centered Labyrinth Seals for Comparison with Experimental LDA Data  

E-Print Network (OSTI)

The flow field in an annular seal is simulated for synchronous circular whirl orbits with 60Hz whirl frequency and a clearance/radius ratio of 0.0154 using the Fluent Computational Fluid Dynamics (CFD) code. Fluent's Moving Reference Frame model...

Vijaykumar, Anand

2011-02-22T23:59:59.000Z

438

Distribution of oceanic 137Cs from the Fukushima Dai-ichi Nuclear Power Plant simulated numerically by a regional ocean model  

Science Journals Connector (OSTI)

Radioactive materials were released to the environment from the Fukushima Dai-ichi Nuclear Power Plant as a result of the reactor accident after the Tohoku earthquake and tsunami of 11 March 2011. The measured 137Cs concentration in a seawater sample near the Fukushima Dai-ichi Nuclear Power Plant site reached 68kBqL?1 (6.8נ104BqL?1) on 6 April. The two major likely pathways from the accident site to the ocean existed: direct release of high radioactive liquid wastes to the ocean and the deposition of airborne radioactivity to the ocean surface. By analysis of the 131I/137Cs activity ratio, we determined that direct release from the site contributed more to the measured 137Cs concentration than atmospheric deposition did. We then used a regional ocean model to simulate the 137Cs concentrations resulting from the direct release to the ocean off Fukushima and found that from March 26 to the end of May the total amount of 137Cs directly released was 3.50.7PBq ((3.50.7)נ1015Bq). The simulated temporal change in 137Cs concentrations near the Fukushima Daini Nuclear Power Plant site agreed well with observations. Our simulation results showed that (1) the released 137Cs advected southward along the coast during the simulation period; (2) the eastward-flowing Kuroshio and its extension transported 137C during May 2011; and (3) 137Cs concentrations decreased to less than 10BqL?1 by the end of May 2011 in the whole simulation domain as a result of oceanic advection and diffusion. We compared the total amount and concentration of 137Cs released from the Fukushima Dai-ichi reactors to the ocean with the 137Cs released to the ocean by global fallout. Even though the measured 137Cs concentration from the Fukushima accident was the highest recorded, the total released amount of 137Cs was not very large. Therefore, the effect of 137Cs released from the Fukushima Dai-ichi reactors on concentration in the whole North Pacific was smaller than that of past release events such as global fallout, and the amount of 137Cs expected to reach other oceanic basins is negligible comparing with the past radioactive input.

Daisuke Tsumune; Takaki Tsubono; Michio Aoyama; Katsumi Hirose

2012-01-01T23:59:59.000Z

439

Radiation transport calculations and simulations  

Science Journals Connector (OSTI)

......obtain with good accuracy. The water content can affect critically...has a density variable with atmospheric pressure. In general, these...uniform pseudo-random number generator. ACM T. Model. Comput...Muraro S., Sala P. R. Atmospheric muon simulation using the......

A. Fass; A. Ferrari; P. R. Sala

2009-11-01T23:59:59.000Z

440

Numerical simulation of the air flow field in a laboratory fume hood using the CFD-ACE(TM) computational fluid dynamics code  

E-Print Network (OSTI)

turbulence models. These models expressed in differential and or algebraic form with the Navier-Stokes and continuity equations make a closed set. The turbulence models simulate the averaged character of the real turbulence. In 1877, Boussinesq proposed... (15) The Reynolds stress tensor based on the Boussinesq assumption is then given by (pp SUJET 2 c~x zsxi (16) where Ps is the Kronecker delta and rc is the kinetic energy of turbulence. In equation 16, o?. . = 1 for i = j and o, = 0 for i w j...

D'Sousa, Cedric Benedict

2012-06-07T23:59:59.000Z

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

NUMERICAL SIMULATIONS OF THE MAGNETIC RAYLEIGH-TAYLOR INSTABILITY IN THE KIPPENHAHN-SCHLUeTER PROMINENCE MODEL. II. RECONNECTION-TRIGGERED DOWNFLOWS  

SciTech Connect

The launch of the Hinode satellite has allowed high-resolution observations of supersonic bright downflows in quiescent prominences, known as prominence knots. We present observations in the Ca II H spectral line using the Solar Optical Telescope on board the Hinode satellite of a descending plasma knot of size {approx}900 km. The knot initially undergoes ballistic motion before undergoing impulsive accelerations at the same time as experiencing increases in intensity. We also present a subset of our three-dimensional magnetohydrodynamic simulations, performed to investigate the nonlinear stability of the Kippenhahn-Shlueter prominence model to the magnetic Rayleigh-Taylor instability in which interchange reconnection occurs. The interchange reconnection in the model breaks the force balance along the field lines which initiates the downflows. The downflows propagate with a downward fluid velocity of {approx}15 km s{sup -1} and a characteristic size of {approx}700 km. We conclude that the observed plasma blob and the simulated downflow are driven by the breaking of the force balance along the magnetic field as a result of a change in magnetic topology caused by reconnection of the magnetic field.

Hillier, Andrew; Isobe, Hiroaki; Shibata, Kazunari [Kwasan and Hida Observatories, Kyoto University, Kyoto (Japan); Berger, Thomas [Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto, CA (United States)

2012-09-10T23:59:59.000Z

442

A Correction Scheme for Thermal Conductivity Measurement Using the Comparative Cut-bar Technique Based on a 3D Numerical Simulation  

SciTech Connect

As an important factor affecting the accuracy of the thermal conductivity measurement, systematic (bias) error in the guarded comparative axial heat flow (cut-bar) method was mostly neglected by previous researches. This bias is due primarily to the thermal conductivity mismatch between sample and meter bars (reference), which is common for a sample of unknown thermal conductivity. A correction scheme, based on a finite element simulation of the measurement system, was proposed to reduce the magnitude of the overall measurement uncertainty. This scheme was experimentally validated by applying corrections on four types of sample measurements in which the specimen thermal conductivity is much smaller, slightly smaller, equal and much larger than that of the meter bar. As an alternative to the optimum guarding technique proposed before, the correction scheme can be used to minimize uncertainty contribution from the measurement system with non-optimal guarding conditions. It is especially necessary for large thermal conductivity mismatches between sample and meter bars.

Douglas W. Marshall; Changhu Xing; Charles Folsom; Colby Jensen; Heng Ban

2014-05-01T23:59:59.000Z

443

Formation of small-scale cyclones in numerical simulations of synoptic-scale baroclinic wave life cycles: Secondary instability at the cusp  

SciTech Connect

An examination of high-resolution simulations of nonlinear baroclinic wave evolution, based upon the nonhydrostatic anelastic equations, has revealed the occurrence of frontal instabilities following cutoff of the primary wave occlusion. The frontal waves are shallow and have horizontal scales of approximately 700 km. They derive their energy from both baroclinic and barotropic energy conversions and it is suggested that they may owe their existence to the instability of a strip of anomalously large potential vorticity that develops along the surface front. The issue of the fundamental mechanism is complicated somewhat because such secondary cyclogenesis events occur at the frontal cusp, a location in which the flow is highly nonparallel. 28 refs., 9 figs.

Polavarapu, S.M.; Peltier, W.R. (Univ. of Toronto, Ontario (Canada))

1993-04-15T23:59:59.000Z

444

Numerical simulation of ground-water flow in the Culebra dolomite at the Waste Isolation Pilot Plant (WIPP) site: Second interim report  

SciTech Connect

This hydrogeologic modeling study has been performed as part of the regional hydrologic characterization of the Waste Isolation Pilot Plant (WIPP) Site in southeastern New Mexico. The study resulted in an estimation of the transmissivity distrubution, hydraulic potentials, flow field, and fluid densities in the Culebra Dolomite Member of the Permian Rustler Formation at the WIPP site. The three-dimensional finite-difference code SWIFT-II was employed for the numerical modeling, using variable-fluid-density and a single-porosity formulation. The modeled area includes and extends beyond the WIPP controlled zone (Zone 3). The work performed consisted of modeling the hydrogeology of the Culebra using two approaches: (1) steady-state modeling to develop the best estimate of the undisturbed head distribution, i.e., of the situation before sinking if the WIPP shafts, which began in 1981; and (2) superimposed transient modeling of local hydrologic responses to excavation of the three WIPP shafts at the center of the WIPP site, as well as to various well tests. Boundary conditions (prescribed constant fluid pressures and densities) were estimated using hydraulic-head and fluid-density data obtained from about 40 wells at and near the WIPP site. The transient modeling used the calculated steady-state freshwater heads as initial conditions. 107 refs., 112 figs., 22 tabs.

LaVenue, A.M.; Haug, A.; Kelley, V.A.

1988-03-01T23:59:59.000Z

445

An appraisal of the power density of current profile in the Persian Gulf and the Gulf of Oman using numerical simulation  

Science Journals Connector (OSTI)

Abstract Having more than 2000km tidal coastline, it's expected that Iran could exploit marine renewable energies. Furthermore, marginal countries around these seas are going to develop their energy resources and marine current energy can be a reliable choice. So, the results of a three dimensional numerical model for the study of circulation in the Persian Gulf and the Gulf of Oman, have been used to assess the power density of ocean currents in these prominent water basins. The calculations are performed regarding converter's dimension and accessibility of the generated power. The results show that the current energy, in the upper 50m layer increases in two periods of the year, late winter to early spring and late summer to early autumn. It can be asserted that the current energy in the study area increases during monsoon periods. According to the model results, the marine current energy in the Persian Gulf and the Gulf of Oman is rather substantial; but it should wait for harnessing as more efficient power conversion systems are available.

Mahmood Akhyani; Vahid Chegini; Abbasali Aliakbari Bidokhti

2015-01-01T23:59:59.000Z

446

High-resolution numerical simulation and analysis of Mach reflection structures in detonation waves in low-pressure H2 - O2 - Ar mixtures: a summary of results obtained with the adaptive mesh refinement framework AMROC  

SciTech Connect

Numerical simulation can be key to the understanding of the multi-dimensional nature of transient detonation waves. However, the accurate approximation of realistic detonations is demanding as a wide range of scales needs to be resolved. This paper describes a successful solution strategy that utilizes logically rectangular dynamically adaptive meshes. The hydrodynamic transport scheme and the treatment of the non-equilibrium reaction terms are sketched. A ghost fluid approach is integrated into the method to allow for embedded geometrically complex boundaries. Large-scale parallel simulations of unstable detonation structures of Chapman-Jouguet detonations in low-pressure hydrogen-oxygen-argon mixtures demonstrate the efficiency of the described techniques in practice. In particular, computations of regular cellular structures in two and three space dimensions and their development under transient conditions, i.e. under diffraction and for propagation through bends are presented. Some of the observed patterns are classified by shock polar analysis and a diagram of the transition boundaries between possible Mach reflection structures is constructed.

Deiterding, Ralf [ORNL

2011-01-01T23:59:59.000Z

447

Simulation of supercritical waterhydrocarbon mixing in a cylindrical tee at intermediate Reynolds number: Formulation, numerical method and laminar mixing  

Science Journals Connector (OSTI)

Abstract The objective of this work is to study the flow dynamics and mixing of supercritical water and a model hydrocarbon (n-decane), under fully miscible conditions, in a small scale cylindrical tee mixer (pipe ID=2.4mm), at an intermediate inlet Reynolds number of 500 using 3-D CFD simulations. A PengRobinson EoS with standard van der Waals mixing rules is employed to model the near-critical thermodynamics with the mixture binary interaction parameter obtained from a Predictive PengRobinson EoS using group contribution theory (PPR78). The n-decane stream is introduced at the colder temperature of 700K to ensure operation above the Upper Critical Solution Temperature (UCST, 632K) of the water n-decane system while the water stream enters at a higher temperature of 800K. Under these conditions, the flow in the tee mixer remains laminar and steady-state is reached. Mixing occurs predominantly due to the circulating action of a counter-rotating vortex pair (CVP) in the body of the hydrocarbon jet entering from the top. This CVP is formed due to the reorientation of the streamwise vorticity pre-existing within the hydrocarbon jet as it flows down the vertical pipe of the tee junction. The advective transport is further assisted by a secondary flow of water from the bottom stream, around the hydrocarbon jet, toward the space vacated near the top of the downstream pipe section by the downward motion of the HC jet. The CVP becomes progressively weaker due to vorticity diffusion as it is advected downstream and beyond 1012 diameter lengths downstream of the mixing joint, transport is mainly controlled by molecular diffusion. It was found that the variations of density and transport properties with temperature do not have a significant impact on the flow and mixing dynamics for a ?T=100K between the two streams. Local cooling of the fluid mixture was also observed in the mixing of water and n-decane streams entering at the same temperature (initially isothermal). This cooling effect is due to the diffusion of species along a gradient in their partial enthalpy in the mixture. Such gradients in species partial enthalpies are non-zero under near-critical conditions even for initially isothermal flows due to the non-ideality of the fluid mixture under these conditions. This local heating/cooling effect at near-critical conditions could give rise to unexpected formation of phases when operating close to critical points.

Ashwin Raghavan; Ahmed F. Ghoniem

2014-01-01T23:59:59.000Z

448

Disruptive Innovation in Numerical Hydrodynamics  

SciTech Connect

We propose the research and development of a high-fidelity hydrodynamic algorithm for tetrahedral meshes that will lead to a disruptive innovation in the numerical modeling of Laboratory problems. Our proposed innovation has the potential to reduce turnaround time by orders of magnitude relative to Advanced Simulation and Computing (ASC) codes; reduce simulation setup costs by millions of dollars per year; and effectively leverage Graphics Processing Unit (GPU) and future Exascale computing hardware. If successful, this work will lead to a dramatic leap forward in the Laboratory's quest for a predictive simulation capability.

Waltz, Jacob I. [Los Alamos National Laboratory

2012-09-06T23:59:59.000Z

449

Numerical Methodology to Evaluate Fast Reactor Sodium Combustion  

SciTech Connect

In the present study, a numerical methodology for sodium combustion has been developed for the safety evaluation of a liquid-metal-cooled fast reactor. The methodology includes a fast-running zone model computer program for safety evaluation, a field model program for multidimensional thermal hydraulics, and a chemical reaction analysis program based on chemical equilibrium theory. Two recently performed experiments have been analyzed using the computer programs, and the numerical results are in good agreement with the experiments. Although sodium combustion is a complex phenomenon, use of these computer programs gives better understanding of the coupled thermal hydraulics and chemical reaction.

Yamaguchi, Akira; Takata, Takashi; Okano, Yasushi [Japan Nuclear Cycle Development Institute (Japan)

2001-12-15T23:59:59.000Z

450

10.34 Numerical Methods Applied to Chemical Engineering, Fall 2001  

E-Print Network (OSTI)

Numerical methods for solving problems arising in heat and mass transfer, fluid mechanics, chemical reaction engineering, and molecular simulation. Topics: numerical linear algebra, solution of nonlinear algebraic equations ...

Beers, Kenneth J.

451

Compositional changes in heavy oil steamflood simulators.  

E-Print Network (OSTI)

??The numerical simulation of heavy oil steamfloods has generally been conducted assuming that the oil is non-volatile. Reservoir simulation has traditionally ignored compositional effect s (more)

Lolley, Christopher Scott

2012-01-01T23:59:59.000Z

452

Numerical simulation of an energy storage well  

E-Print Network (OSTI)

the sequent voluse, RdRb85Z, equation 6 becoaes (RdBdZdm +d~+RdRd8~)?(RdR61)dZsn ), Condensinq the sass flow (B T w ) terna to: MR -RdBdZ ? ~ ~ ~ es so ~ ~ ~ ~ ~ o f Ba] Mw -dKLZ ? Pf ~ f Bh] and [ h, p, /aP Mz=RS pg e ~ ~ ~ ~ ~ e ~ ~ ~ ~ ~ s ~ [~p BZ...Ma+ 4?z?z)t. t g. t +(dMm+ +dMv +dMz+M~ )v~ tqg ] trauma/z zg jig, t+1/z v ~ f 'l2a] n+dMv z Mz)ri~t +(dMn" '+dM " '+~z+Mi), ps, t+, ] tnatz/v ~s. r, l, xttt/zv and ~ f 12b] / [(dMm+dM +Mz+M, ), ?s, +(dMn" '+dMm+' +dM, + ~M, ). . . ] 21 era+I +5...

Ebeling, Lynn Louis

2012-06-07T23:59:59.000Z

453

NUMERICAL SIMULATION OF INCOMPRESSIBLE FLOWS IN ...  

E-Print Network (OSTI)

u, v and w respectively, and f, g, h, q are functions depending on the solutions at .... and letting A, B, C, D, E, F and U be the corresponding matrices with entries.

454

Numerical simulation investigations in weapon delivery probabilities .  

E-Print Network (OSTI)

??The study of weapon delivery probabilities has historically been focused around analytical solutions and approximations for weapon delivery accuracy and effectiveness calculations. With the relatively (more)

Peterson, Kristofer A.

2008-01-01T23:59:59.000Z

455

Direct numerical simulation of turbulent mixing  

Science Journals Connector (OSTI)

...in-[5]. The low-cost approach to turbulence...growing with n. The graphs corresponding to these...rates-both chemical and nuclear. The same is true for...Figure-17 shows the graph of the TMZ boundary dependence...of providing safety in nuclear power production facilities...

2013-01-01T23:59:59.000Z

456

Direct numerical simulations of aeolian sand ripples  

Science Journals Connector (OSTI)

...where the shear velocity up is defined by...the average fluid velocity field by a Prandtl-like...around a given x from mass conservation: Z x...the grain upward velocity and the sum is over...to three different wind shear velocities...image, showing the map of the grain volume...

Orencio Durn; Philippe Claudin; Bruno Andreotti

2014-01-01T23:59:59.000Z

457

Numerical simulations of radiatively driven dusty winds  

Science Journals Connector (OSTI)

......find that, after wind acceleration begins...that the asymptotic wind momentum flux from...constrains the expected mass-loss rates from...we provide a first map of the column density...radiatively driven wind as a function of velocity, and velocity dispersion......

Mark R. Krumholz; Todd A. Thompson

2013-01-01T23:59:59.000Z

458

NUMERICAL SIMULATION OF MULTIPOLE CONFINEMENT (Examples)  

E-Print Network (OSTI)

delphia APS meeting in November 1973. All cases are for neutral H 2 background. The excitation energy loss energy, so that little ionization occurs. As a result, the density builds steadily to a maximum at late at ionizing the neutrals. This ionization raises the charged particle density and thus lowers the heating rate

Sprott, Julien Clinton

459

Numerical Simulation of Aerated Powder Consolidation1  

E-Print Network (OSTI)

applications. Typically a powder is stored in a bunker or silo, see Figure 1. During filling, air gets trapped of the container are neglected, in effect, treating only the case of cylindrical bunkers. In [4], that case. 1 #12;H(t) z bunker top surface z A(z) = R(z) 2 A(z+ z) = R(z+ z) 2 FIG. 1. Geometry and coordinate

460

Numerical Simulation of Aerated Powder Consolidation 1  

E-Print Network (OSTI)

applications. Typically a powder is stored in a bunker or silo, see Figure 1. During filling, air gets trapped of the container are neglected, in effect, treating only the case of cylindrical bunkers. In [4], that case. 1 #12; 2 K.A. KRISTY AND P.A. GREMAUD H(t) z bunker top surface dz A(z) = R(z) p 2 A(z+ z) = R(z+ z

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Direct Numerical Simulation of Cosmological Reionization /  

E-Print Network (OSTI)

2004). We are focusing on EoR which occured after the Dark2004). We are focusing on EoR which occured after the DarkEpoch of Reionization (EoR). In Figure 1.1, a brief history

So, Geoffrey C.

2013-01-01T23:59:59.000Z

462

Numerical simulation and modeling of carbon nanotubes.  

E-Print Network (OSTI)

??The discovery of carbon nanotubes has triggered a significant amount of interest. Since then, much research has been done on these new forms of carbon (more)

Wong, Chee How.

2008-01-01T23:59:59.000Z

463

Numerical simulation of corneal transport processes  

Science Journals Connector (OSTI)

...describe how these ionic species are interrelated and interact on each other (Kuang et...stroma are derived based on the transport processes developed for electrolytic solutions...from the thermodynamics of irreversible processes. The influence of the flow across the...

2006-01-01T23:59:59.000Z

464

A numerical sensitivity analysis of streamline simulation  

E-Print Network (OSTI)

.1 Finite difference cell showing XYZ definitions y QV y QV z QV z QV z QV z QV B B T T S S N N W W E E ??== ??== ??== ? ? ? , , , (2.12) Where Q is a volume flow rate across a cell face, and ? x, ? y, and ? z are the dimensions of the cell....1 Finite difference cell showing XYZ definitions y QV y QV z QV z QV z QV z QV B B T T S S N N W W E E ??== ??== ??== ? ? ? , , , (2.12) Where Q is a volume flow rate across a cell face, and ? x, ? y, and ? z are the dimensions of the cell...

Chaban Habib, Fady Ruben

2005-02-17T23:59:59.000Z

465

Sandia National Laboratories: Numerical Simulations of Hydrokinetics...  

NLE Websites -- All DOE Office Websites (Extended Search)

study, three grids were generated, all of which use the same bathymetric data for the Roza Canal. Converged results were achieved with the 19,777-cell grid. Because...

466

Definition: Numerical Modeling | Open Energy Information  

Open Energy Info (EERE)

Definition Definition Edit with form History Facebook icon Twitter icon » Definition: Numerical Modeling Jump to: navigation, search Dictionary.png Numerical Modeling A computer model that is designed to simulate and reproduce the mechanisms of a particular system.[1] View on Wikipedia Wikipedia Definition A computer simulation, a computer model, or a computational model is a computer program, run on a single computer, or a network of computers, that attempts to simulate an abstract model of a particular system. Computer simulations have become a useful part of mathematical modeling of many natural systems in physics, astrophysics, chemistry and biology, human systems in economics, psychology, social science, and engineering. Simulation of a system is represented as the running of the system's model.

467

A restructurable logic simulator  

E-Print Network (OSTI)

elements were strictly binary and time was uniformly quantized. Interconnection information was used to confine simulation effort to active portions of the )ogic network. Delay was modeled with an event scheduling scheme, where logic state transitions... I7. g). Logic )evels become voltages and state transitions become transient responses. The circuit simulators include the effects of numerous parameters in their device models, and then generate their answers by numerically solving systems...

Ledford, Gordon Lee

2012-06-07T23:59:59.000Z

468

Fundamental properties of solar-like oscillating stars from frequencies of minimum I. Model computations for solar composition  

Science Journals Connector (OSTI)

......Model computations for solar composition M. Yz...defining characteristic of solar-like oscillations. The space projects Kepler and CoRoT give...mass and radius of a solar-like oscillating...transformation between the energy transportation mechanisms......

M. Y?ld?z; Z. elik Orhan; . Aksoy; S. Ok

2014-01-01T23:59:59.000Z

469

Causality and sensitivity analysis in distributed design simulation  

E-Print Network (OSTI)

Numerous collaborative design frameworks have been developed to accelerate the product development, and recently environments for building distributed simulations have been proposed. For example, a simulation framework ...

Kim, Jaehyun, 1970-

2002-01-01T23:59:59.000Z

470

Presented by High Fidelity Direct Numerical  

E-Print Network (OSTI)

Presented by High Fidelity Direct Numerical Simulations of Turbulent Combustion Jacqueline H. Chen (PI), Chun Sang Yoo, Gaurav Bansal, Hongfeng Yu, Ajith Mascarenhas Combustion Research Facility Sandia) of turbulent combustion DNS approach and role � Fully resolve all continuum scales without using subgrid models

471

Numerical study of high heat ux pool boiling heat transfer Ying He a,*, Masahiro Shoji b  

E-Print Network (OSTI)

Numerical study of high heat ¯ux pool boiling heat transfer Ying He a,*, Masahiro Shoji b , Shigeo simulation model of boiling heat transfer is proposed based on a numerical macrolayer model [S. Maruyama, M. Shoji, S. Shimizu, A numerical simulation of transition boiling heat transfer, in: Proceedings

Maruyama, Shigeo

472

USING LEARNING MACHINES TO CREATE SOLAR RADIATION MAPS FROM NUMERICAL WEATHER PREDICTION MODELS,  

E-Print Network (OSTI)

USING LEARNING MACHINES TO CREATE SOLAR RADIATION MAPS FROM NUMERICAL WEATHER PREDICTION MODELS simulation by means of a Numerical Weather Prediction Model (NWP), Skiron. After that, we have made spatial solar resource map. 2.1. Meteorological simulation The numerical weather prediction model used is SKIRON

Paris-Sud XI, Université de

473

High performance computing and numerical modelling  

E-Print Network (OSTI)

Numerical methods play an ever more important role in astrophysics. This is especially true in theoretical works, but of course, even in purely observational projects, data analysis without massive use of computational methods has become unthinkable. The key utility of computer simulations comes from their ability to solve complex systems of equations that are either intractable with analytic techniques or only amenable to highly approximative treatments. Simulations are best viewed as a powerful complement to analytic reasoning, and as the method of choice to model systems that feature enormous physical complexity such as star formation in evolving galaxies, the topic of this 43rd Saas Fee Advanced Course. The organizers asked me to lecture about high performance computing and numerical modelling in this winter school, and to specifically cover the basics of numerically treating gravity and hydrodynamics in the context of galaxy evolution. This is still a vast field, and I necessarily had to select a subset ...

,

2014-01-01T23:59:59.000Z

474

Jordan Form Numerical. . .  

E-Print Network (OSTI)

Similarity Jordan Form Numerical. . . Applications Proofs Basis change A short proof Home Page, Alabama, USA Oct 3, 2007 Jordan Normal Form Revisited Speaker: Tin-Yau Tam Graduate Student Seminar tamtiny@auburn.edu #12;Similarity Jordan Form Numerical. . . Applications Proofs Basis change A short

Tam, Tin-Yau

475

Plasma theory and simulation research  

SciTech Connect

Our research group uses both theory and simulation as tools in order to increase the understanding of instabilities, heating, diffusion, transport and other phenomena in plasmas. We also work on the improvement of simulation, both theoretically and practically. Our focus has been more and more on the plasma edge (the sheath''), interactions with boundaries, leading to simulations of whole devices (someday a numerical tokamak).

Birdsall, C.K.

1989-01-01T23:59:59.000Z

476

A numerical investigation of collisionality and turbulent transport  

E-Print Network (OSTI)

An investigation of collisionality's role in turbulent transport in magnetized plasma using the GS2 gyrokinetic simulation software is presented. The investigation consists of three parts, conducted by way of numerical ...

Lindsey, Martin L., S.B. Massachusetts Institute of Technology

2014-01-01T23:59:59.000Z

477

Numerical Investigation of Solar Chimney Power Plant in UAE  

Science Journals Connector (OSTI)

This paper presents a numerical simulation results for a steady air flow inside a solar chimney power plant. A standard k-epsilon turbulence model is used to model a prototype solar chimney that was built in Al A...

Mohammad O. Hamdan; Saud Khashan

2014-01-01T23:59:59.000Z

478

Numerical simulation of thin-shell direct drive DHe3-filled capsules fielded A. R. Miles, H.-K. Chung, R. Heeter, W. Hsing, J. A. Koch et al.  

E-Print Network (OSTI)

and rebounding in a high-intensity CO2 laser induced air plasma Phys. Plasmas 19, 073302 (2012) Feasibility to the DHe3 gas fill, in quantities sufficient to have an impact on yields, compression, and cooling rates in compressions that can be an order of magnitude higher than in undoped capsules. A baseline LASNEX simulation

479

Numerical evidence of turbulence generated by non-breaking surface waves  

Science Journals Connector (OSTI)

Numerical simulation of monochromatic surface waves propagating over a turbulent field is conducted to reveal the mechanism of turbulence production by non-breaking waves. The numerical model solves the primitive equations subject to the fully ...

Wu-ting Tsai; Shi-ming Chen; Guan-hung Lu

480

A study of a two-stroke free piston linear engine using numerical analysis  

Science Journals Connector (OSTI)

We studied a two-stroke free piston linear engine by numerical models and simulation. The numerical ... ratio, reciprocating mass, spark timing, and spring stiffness on the operating characteristics as well as pe...

Nguyen Ba Hung; Ock Taeck Lim

2014-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling-computer simulations numerical" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

LAB #8 Numerical Methods  

E-Print Network (OSTI)

Required tools: Matlab routine dfield ; numerical routines eul, rk2, rk4; m-files. Discussion ... You should get a piecewise linear graph made up .... in the matrix y

2005-10-20T23:59:59.000Z

482

An investigation of numerical dispersion in the hot water injection process  

E-Print Network (OSTI)

dispersion is important in the simulation of the hot water injection process with heat loss. Numerical results are compared to the analytical solution of the simple convective-diffusion problem and Lauwerier's analytical solution to the hot water... simulated, then some type of method for controlling numerical dispersion will have to be implemented. It is obvious from the numerical results that numerical dispersion is affected by injection velocity and distance travelled, but these variables do...

McVay, Duane Allen

2012-06-07T23:59:59.000Z

483

E-Print Network 3.0 - adaptive numerical dissipative Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

rate. Through numerical simulations, we find... description (i) Dissipative, vortex-vortex forces ... Source: Grzybowski, Bartosz A. - Departments of Chemistry & Chemical...

484

VALIDATION OF MASSIVELY PARALLEL SIMULATIONS OF DYNAMIC FRACTURE AND  

E-Print Network (OSTI)

VALIDATION OF MASSIVELY PARALLEL SIMULATIONS OF DYNAMIC FRACTURE AND FRAGMENTATION OF BRITTLE element simulations of dynamic fracture and fragmentation of brittle solids are presented. Fracture the results of massively parallel numerical simulations of dynamic fracture and fragmentation in brittle

Barr, Al

485

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING Int. J. Numer. Meth. Engng 2011; 86:15441557  

E-Print Network (OSTI)

. Frey1,2 1UPMC Univ Paris 06, UMR 7598, Laboratoire J.L. Lions, F-75005 Paris, France 2Universidad de present a three-dimensional numerical simulation on a mechanical device. Copyright 2011 John Wiley & Sons.L. Lions, F-75005 Paris, France. E-mail: debuhan@ann.jussieu.fr Copyright 2011 John Wiley & Sons, Ltd. #12

Frey, Pascal

486

Temporal Changes in Wind as Objects for Evaluating Mesoscale Numerical Weather Prediction  

Science Journals Connector (OSTI)

The study describes a method of evaluating numerical weather prediction models by comparing the characteristics of temporal changes in simulated and observed 10-m (AGL) winds. The method is demonstrated on a 1-yr collection of 1-day simulations ...

Daran L. Rife; Christopher A. Davis; Jason C. Knievel

2009-10-01T23:59:59.000Z

487

Numerical aspects of 3D stellar winds  

E-Print Network (OSTI)

This paper explores and compares the pitfalls of modelling the three-dimensional wind of a spherical star with a cartesian grid. Several numerical methods are compared, using either uniform and stretched grid or adaptative mesh refinement (AMR). An additional numerical complication is added, when an orbiting planet is considered. In this case a rotating frame is added to the model such that the orbiting planet is at rest in the frame of work. The three-dimensional simulations are systematically compared to an equivalent two-dimensional, axisymmetric simulation. The comparative study presented here suggests to limit the rotation rate of the rotating frame below the rotating frame of the star and provides guidelines for further three-dimensional modelling of stellar winds in the context of close-in star-planet interactions.

Strugarek, A; Matt, S P; Reville, V

2014-01-01T23:59:59.000Z

488

Predictive Simulation | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Predictive Predictive Simulation Predictive Simulation Empirical To First Principle Models Computing tools currently used in nuclear industry and regulatory practice are based primarily on empirical math models to approximate, or fit, existing experimental data. Many have a pedigree reaching back to the 1970s and 1980s and were designed to support decision making and evaluate everything from behavior of individual fuel pellets to severe accident scenarios for an entire power plant. Programs like SAPHIRE, FRAPCON, RELAP5, and MELCOR are just a few examples of current computing tools used in the regulation and operation of nuclear power plants. While these conventional tools have been updated for today's technology, they still suffer from limitations of their original

489

Higher-dimensional numerical relativity: Formulation and code tests  

SciTech Connect

We derive a formalism of numerical relativity for higher-dimensional spacetimes and develop numerical codes for simulating a wide variety of five-dimensional (5D) spacetimes for the first time. First, the Baumgarte-Shapiro-Shibata-Nakamura formalism is extended for arbitrary spacetime dimensions D{>=}4, and then, the so-called cartoon method, which was originally proposed as a robust method for simulating axisymmetric 4D spacetimes, is described for 5D spacetimes of several types of symmetries. Implementing 5D numerical relativity codes with the cartoon methods, we perform test simulations by evolving a 5D Schwarzschild spacetime and a 5D spacetime composed of a gravitational-wave packet of small amplitude. The numerical simulations are stably performed for a sufficiently long time, as done in the 4D case, and the obtained numerical results agree well with the analytic solutions: The numerical solutions are shown to converge at the correct order. We also confirm that a long-term accurate evolution of the 5D Schwarzschild spacetime is feasible using the so-called puncture approach. In addition, we derive the Landau-Lifshitz pseudotensor in arbitrary dimensions, and show that it gives a robust tool for computing the energy flux of gravitational waves. The formulations and methods developed in this paper provide a powerful tool for studying nonlinear dynamics of higher-dimensional gravity.

Yoshino, Hirotaka; Shibata, Masaru [Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2G7 (Canada); Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto, 606-8502 (Japan)

2009-10-15T23:59:59.000Z

490