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1

Gyrokinetic large eddy simulations  

SciTech Connect (OSTI)

The large eddy simulation approach is adapted to the study of plasma microturbulence in a fully three-dimensional gyrokinetic system. Ion temperature gradient driven turbulence is studied with the GENE code for both a standard resolution and a reduced resolution with a model for the sub-grid scale turbulence. A simple dissipative model for representing the effect of the sub-grid scales on the resolved scales is proposed and tested. Once calibrated, the model appears to be able to reproduce most of the features of the free energy spectra for various values of the ion temperature gradient.

Morel, P.; Navarro, A. Banon; Albrecht-Marc, M.; Carati, D. [Statistical and Plasma Physics Laboratory, Universite Libre de Bruxelles, Bruxelles 1050 (Belgium); Merz, F.; Goerler, T.; Jenko, F. [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. 2, D-85748 Garching (Germany)

2011-07-15T23:59:59.000Z

2

Large-eddy simulations of scramjet engines.  

E-Print Network [OSTI]

??The main objective of this dissertation is to develop large-eddy simulation (LES) based computational tools for supersonic inlet and combustor design. In the recent past,… (more)

Koo, Heeseok

2011-01-01T23:59:59.000Z

3

Large Eddy Simulation (LES) Applied to Advanced Engine Combustion...  

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

Advanced Engine Combustion Research Large Eddy Simulation (LES) Applied to Advanced Engine Combustion Research 2012 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies...

4

Large Eddy Simulation (LES) Applied to LTC/Diesel/Hydrogen Engine...  

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

Large Eddy Simulation (LES) Applied to LTCDieselHydrogen Engine Combustion Research Large Eddy Simulation (LES) Applied to LTCDieselHydrogen Engine Combustion Research 2009 DOE...

5

Large-Eddy Simulation of Wind-Plant Aerodynamics: Preprint  

SciTech Connect (OSTI)

In this work, we present results of a large-eddy simulation of the 48 multi-megawatt turbines composing the Lillgrund wind plant. Turbulent inflow wind is created by performing an atmospheric boundary layer precursor simulation and turbines are modeled using a rotating, variable-speed actuator line representation. The motivation for this work is that few others have done wind plant large-eddy simulations with a substantial number of turbines, and the methods for carrying out the simulations are varied. We wish to draw upon the strengths of the existing simulations and our growing atmospheric large-eddy simulation capability to create a sound methodology for performing this type of simulation. We have used the OpenFOAM CFD toolbox to create our solver.

Churchfield, M. J.; Lee, S.; Moriarty, P. J.; Martinez, L. A.; Leonardi, S.; Vijayakumar, G.; Brasseur, J. G.

2012-01-01T23:59:59.000Z

6

Large-eddy simulation of multiphase flows in complex combustors  

E-Print Network [OSTI]

Large-eddy simulation of multiphase flows in complex combustors S. V. Apte1 , K. Mahesh2 , F. Ham1 to accurately predict reacting multi-phase flows in practical combustors involving complex physical phenomena-turbine combustor geometries to evaluate the predictions made for multiphase, turbulent flow. 1 Introduction

Mahesh, Krishnan

7

Applications of large eddy simulation methods to gyrokinetic turbulence  

SciTech Connect (OSTI)

The large eddy simulation (LES) approach—solving numerically the large scales of a turbulent system and accounting for the small-scale influence through a model—is applied to nonlinear gyrokinetic systems that are driven by a number of different microinstabilities. Comparisons between modeled, lower resolution, and higher resolution simulations are performed for an experimental measurable quantity, the electron density fluctuation spectrum. Moreover, the validation and applicability of LES is demonstrated through a series of diagnostics based on the free energetics of the system.

Bañón Navarro, A., E-mail: alejandro.banon.navarro@ipp.mpg.de; Happel, T. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)] [Max-Planck-Institut für Plasmaphysik, EURATOM Association, D-85748 Garching (Germany); Teaca, B. [Applied Mathematics Research Centre, Coventry University, Coventry CV1 5FB (United Kingdom) [Applied Mathematics Research Centre, Coventry University, Coventry CV1 5FB (United Kingdom); Max-Planck für Sonnensystemforschung, Max-Planck-Str. 2, D-37191 Katlenburg-Lindau (Germany); Max-Planck/Princeton Center for Plasma Physics (Germany); Jenko, F. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, D-85748 Garching (Germany) [Max-Planck-Institut für Plasmaphysik, EURATOM Association, D-85748 Garching (Germany); Max-Planck/Princeton Center for Plasma Physics (Germany); Hammett, G. W. [Max-Planck/Princeton Center for Plasma Physics, Princeton Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey 08543 (United States)] [Max-Planck/Princeton Center for Plasma Physics, Princeton Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey 08543 (United States); Collaboration: ASDEX Upgrade Team

2014-03-15T23:59:59.000Z

8

Large Eddy Simulation (LES) Applied to Low-Temperature and Diesel...  

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

Combustion Research Large Eddy Simulation (LES) Applied to Low-Temperature and Diesel Engine Combustion Research 2011 DOE Hydrogen and Fuel Cells Program, and Vehicle...

9

Large-Eddy Simulation of the Bachalo-Johnson Flow, with Shock...  

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

Travin, New Technologies and Services, Ltd. Large-Eddy Simulation of the Bachalo-Johnson Flow, with Shock-Induced Separation PI Name: Philippe Spalart PI Email:...

10

Large eddy simulation of one diffusion swirling flame European Combustion Meeting 2011  

E-Print Network [OSTI]

.5 7200 75900 Numerical method This research use large eddy simulation (LES) in software ANASYS FLUENT Simulations of Swirling Non-premixed Flames With Flamelet Models: A Comparison of Numerical Methods. FlowLarge eddy simulation of one diffusion swirling flame European Combustion Meeting 2011 Introduction

Berning, Torsten

11

Modeling dilute sediment suspension using large-eddy simulation with a dynamic mixed model  

E-Print Network [OSTI]

Modeling dilute sediment suspension using large-eddy simulation with a dynamic mixed model Yi Transport of suspended sediment in high Reynolds number channel flows Re=O 600 000 is simulated using large-eddy simulation along with a dynamic-mixed model DMM . Because the modeled sediment concentration is low

Fringer, Oliver B.

12

Implicit Large Eddy Simulation of Cavitation in Micro Channel Flows  

E-Print Network [OSTI]

We present a numerical method for Large Eddy Simulations (LES) of compressible two-phase flows. The method is validated for the flow in a micro channel with a step-like restriction. This setup is representative for typical cavitating multi-phase flows in fuel injectors and follows an experimental study of Iben et al., 2010. While a diesel-like test fuel was used in the experiment, we solve the compressible Navier-Stokes equations with a barotropic equation of state for water and vapor and a simple phase-change model based on equilibrium assumptions. Our LES resolve all wave dynamics in the compressible fluid and the turbulence production in shear layers.

Hickel, S; Schmidt, S J

2014-01-01T23:59:59.000Z

13

Large-eddy simulation of a wind turbine wake in turbulent  

E-Print Network [OSTI]

Large-eddy simulation of a wind turbine wake in turbulent neutral shear flow Shengbai Xie, Cristina-similar velocity profile existing in the wake after a wind turbine? How does the wake influence the vertical? Motivation #12; Large-eddy simulation for turbulent flow field Actuator-line model for wind turbine ui

Firestone, Jeremy

14

Flame Stability Analysis in an Ultra Compact Combustor Using Large-Eddy Simulation  

E-Print Network [OSTI]

Flame Stability Analysis in an Ultra Compact Combustor Using Large-Eddy Simulation C. Lietz , C Base, Ohio 45433 Large eddy simulation (LES) of an experimental ultra-compact combustor (UCC as a conven- tional combustor path. In order to reduce the penalty due to increased weight of these burners

Raman, Venkat

15

Large-eddy simulation of swirling particle-laden flows in a coaxial-jet combustor  

E-Print Network [OSTI]

Large-eddy simulation of swirling particle-laden flows in a coaxial-jet combustor S.V. Apte a,* , K 2003 Abstract Large-eddy simulation (LES) of particle-laden, swirling flow in a coaxial-jet combustor;cyclone combustors, and biomass gasifiers (Lefebvre, 1989). The physics of such flows is extremely complex

Apte, Sourabh V.

16

On the self-similarity assumption in dynamic models for large eddy simulations  

E-Print Network [OSTI]

that the present formulation of the DP is usually incompatible with its under- lying self-similarity assumption SSAOn the self-similarity assumption in dynamic models for large eddy simulations Daniele Carati eddy simulations and their underlying self-similarity assumption is discussed. The interpretation

Van Den Eijnden, Eric

17

Toward the Large-Eddy Simulation Over a Hypersonic Elliptical Cross-Section Cone  

E-Print Network [OSTI]

Toward the Large-Eddy Simulation Over a Hypersonic Elliptical Cross-Section Cone M. Pino Mart layer. Also, the computational setup for the large-eddy sim- ulation (LES) of a hypersonic elliptical cross-section cone is discussed in detail. Introduction The aerodynamic heating effects in hypersonic

Martín, Pino

18

Large-Eddy Simulation of Flow and Pollutant Transport in Urban Street Canyons with Ground Heating  

E-Print Network [OSTI]

Our study employed large-eddy simulation (LES) based on a one-equation subgrid-scale model to investigate the flow field and pollutant dispersion characteristics inside urban street canyons. Unstable thermal stratification ...

Li, Xian-Xiang

19

Calculation of unsteady turbulent flow around obstacles using the large eddy simulation turbulence model  

E-Print Network [OSTI]

The premise of the work presented here is to use a common analytical tool, Computational Fluid Dynamics (CFD), along with a prevalent turbulence model, Large Eddy Simulation (LES), to study the flow past rectangular cylinders. In an attempt to use...

Helton, Donald McLean

2002-01-01T23:59:59.000Z

20

Large-Eddy Simulation of Post-Cold-Frontal Continental Stratocumulus  

E-Print Network [OSTI]

Previous large-eddy simulations (LES) of stratocumulus-topped boundary layers have been exclusively set in marine environments. Boundary layer stratocumulus clouds are also prevalent over the continent but have not been ...

Mechem, David B.; Kogan, Yefim L.; Schultz, David M.

2010-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "large eddy simulation" 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

Investigation of two-fluid methods for Large Eddy Simulation of spray combustion in Gas Turbines  

E-Print Network [OSTI]

Investigation of two-fluid methods for Large Eddy Simulation of spray combustion in Gas Turbines the EL method well suited for gas turbine computations, but RANS with the EE approach may also be found

22

Turbulence prediction in two- and three-dimensional bundle flows using Large Eddy Simulation  

E-Print Network [OSTI]

TURBULENCE PREDICTION IN TWO- AND THREE-DIMENSIONAL BUNDLE FLOWS USING LARGE EDDY SIMULATION A Thesis by WAEL ABDUL-HAMID IBRAHIM Submitted to Texas A&M University in partial fulfillment of the requirements for the degree of MASTER... Prediction in Two- and Three-Dimensional Bundle Flows Using Large Eddy Simulation. (May 1994) Wael Abdul-Hamid Ibrahim, B. S. Alexandria University Chair of Advisory Committee: Dr. Yassin A. Hassan Flow turbulence is a familiar phenomenon in everyday life...

Ibrahim, Wael Abdul-Hamid

1994-01-01T23:59:59.000Z

23

Large-eddy Simulation of Realistic Gas Turbine Combustors , & Apte, S. V.  

E-Print Network [OSTI]

Large-eddy Simulation of Realistic Gas Turbine Combustors Moin, P. , & Apte, S. V. Center models and the numerical scheme is performed in canonical and complex combustor geometries. Finally, a multi-scale, multi-physics, turbulent reacting flow simulation in a real gas-turbine combustor

Apte, Sourabh V.

24

Extracting the Acoustic pressure field from Large Eddy Simulation of confined reactive flows  

E-Print Network [OSTI]

and non-premixed open flames3,4 as well as in more complex cases such as gas turbine combustors must be large enough to include the sources of noise as well as part of the acoustic near field.6 VeryExtracting the Acoustic pressure field from Large Eddy Simulation of confined reactive flows Camilo

Nicoud, Franck

25

3D chaotic model for sub-grid turbulent dispersion in Large Eddy Simulations  

E-Print Network [OSTI]

We introduce a 3D multiscale kinematic velocity field as a model to simulate Lagrangian turbulent dispersion. The incompressible velocity field is a nonlinear deterministic function, periodic in space and time, that generates chaotic mixing of Lagrangian trajectories. Relative dispersion properties, e.g. the Richardson's law, are correctly reproduced under two basic conditions: 1) the velocity amplitudes of the spatial modes must be related to the corresponding wavelengths through the Kolmogorov scaling; 2) the problem of the lack of "sweeping effect" of the small eddies by the large eddies, common to kinematic simulations, has to be taken into account. We show that, as far as Lagrangian dispersion is concerned, our model can be successfully applied as additional sub-grid contribution for Large Eddy Simulations of the planetary boundary layer flow.

Guglielmo Lacorata; Andrea Mazzino; Umberto Rizza

2007-11-15T23:59:59.000Z

26

Large-Eddy Simulation of a Supersonic Inlet-Isolator Heeseok Koo1  

E-Print Network [OSTI]

-mode scramjet engine that pro- vides stable compressed flow to the combustor. However, if the combustor scramjet engines. Here, the predictive capa- bility of the large eddy simulation (LES) methodology-mode scramjets provide a practical solution to hypersonic flight by operating at both low and high supersonic

Raman, Venkat

27

Conjugate Heat Transfer with Large Eddy Simulation for Gas Turbine Components.  

E-Print Network [OSTI]

Conjugate Heat Transfer with Large Eddy Simulation for Gas Turbine Components. Florent Duchaine constraint for GT (gas turbines). Most existing CHT tools are developped for chained, steady phenomena. A film-cooled turbine vane is then studied. Thermal conduction in the blade implies lower wall

Nicoud, Franck

28

Massively-Parallel Spectral Element Large Eddy Simulation of a Ring-Type Gas Turbine Combustor  

E-Print Network [OSTI]

The average and fluctuating components in a model ring-type gas turbine combustor are characterized using a Large Eddy Simulation at a Reynolds number of 11,000, based on the bulk velocity and the mean channel height. A spatial filter is applied...

Camp, Joshua Lane

2012-07-16T23:59:59.000Z

29

Large Eddy Simulation Analysis of Flow Field Inside a High-g Combustor  

E-Print Network [OSTI]

Large Eddy Simulation Analysis of Flow Field Inside a High-g Combustor C. Heye , C. Lietz , J-compact combustors (UCC) are a technology for reducing the size of combustors. In these combustors the fuel and air results exhibit significant entrainment of fuel into recirculation zones inside the combustor, however

Raman, Venkat

30

Large-eddy simulation of lean hydrogenemethane turbulent premixed flames in the methane-  

E-Print Network [OSTI]

Large-eddy simulation of lean hydrogenemethane turbulent premixed flames in the methane- dominated to available experimental data. The enriched flame has 20% H2 in terms of mole fraction and lies in the methane methane flame in the methane- dominated regime. Copyright ª 2014, Hydrogen Energy Publications, LLC

Gülder, �mer L.

31

Computing combustion noise by combining Large Eddy Simulations with analytical models for the propagation of waves  

E-Print Network [OSTI]

Computing combustion noise by combining Large Eddy Simulations with analytical models +++++ Presented by Ignacio Duran Abstract Two mechanisms control combustion noise generation as shown by Marble. A method to calculate combustion-generated noise has been implemented in a tool called CHORUS. The method

Paris-Sud XI, Université de

32

Large Eddy Simulation of Supersonic Combustion using Direct Quadrature Method of Moments  

E-Print Network [OSTI]

. Supersonic combustion involves the interaction of complex gas-phase chemical reactions in a compressible flowLarge Eddy Simulation of Supersonic Combustion using Direct Quadrature Method of Moments Pratik modeling problem. In supersonic combustion, typical closures based on conserved scalar approaches cannot

Raman, Venkat

33

Large-eddy Simulation of the Nighttime Stable Atmospheric Boundary Layer  

E-Print Network [OSTI]

eddy Simulation of Wind-turbine Wakes: Evaluation of Turbineperformed LES of wind-turbine wakes in neutrally stratified

Zhou, Bowen

2012-01-01T23:59:59.000Z

34

Examination of steam generator turbulence by large eddy simulation  

E-Print Network [OSTI]

techniques (Biringen, ei ah 1981; Yakhot et al. 1986). Clark et ah (1979) quantified the various subgrid scale (SGS) terms in LES by comparing their results to a direct simulation. Schumann (1975) used an integral conservation equation combined with an SGS... in the past . The most important interactions are: fluidelastic instability, vortex shedding, turbulent buffeting, and acoustic resonance. Fluidelastic instability results from a coupled fluid-tube force interaction. The instability is also thought...

Bagwell, Ted Glyn

1989-01-01T23:59:59.000Z

35

Investigation of transition to turbulence at low Reynolds numbers using Implicit Large Eddy Simulations with a Discontinuous Galerkin method  

E-Print Network [OSTI]

The present work predicts the formation of laminar separation bubbles at low Reynolds numbers and the related transition to turbulence. In addition to being one of the first Implicit Large Eddy Simulation studies using a ...

Uranga Cabrera, Alejandra (Uranga)

2011-01-01T23:59:59.000Z

36

Vehicle Technologies Office Merit Review 2014: Large Eddy Simulation (LES) Applied to Advanced Engine Combustion Research  

Broader source: Energy.gov [DOE]

Presentation given by Sandia National Laboratories at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about large eddy...

37

Implicit large eddy simulations of anisotropic weakly compressible turbulence with application to core-collapse supernovae  

E-Print Network [OSTI]

(Abridged) In the implicit large eddy simulation (ILES) paradigm, the dissipative nature of high-resolution shock-capturing schemes is exploited to provide an implicit model of turbulence. Recent 3D simulations suggest that turbulence might play a crucial role in core-collapse supernova explosions, however the fidelity with which turbulence is simulated in these studies is unclear. Especially considering that the accuracy of ILES for the regime of interest in CCSN, weakly compressible and strongly anisotropic, has not been systematically assessed before. In this paper we assess the accuracy of ILES using numerical methods most commonly employed in computational astrophysics by means of a number of local simulations of driven, weakly compressible, anisotropic turbulence. We report a detailed analysis of the way in which the turbulent cascade is influenced by the numerics. Our results suggest that anisotropy and compressibility in CCSN turbulence have little effect on the turbulent kinetic energy spectrum and a...

Radice, David; Ott, Christian D

2015-01-01T23:59:59.000Z

38

Researchers at the National Renewable Energy Laboratory (NREL) develop a high-fidelity large-eddy simulation model  

E-Print Network [OSTI]

to simulate events such as frontal passages through a wind plant and their effect on turbine power production-eddy simulation model designed to predict the performance of large wind plants with a higher degree of accuracy larger, but the power production of these large plants has, in some cases, been lower than initially

39

Large Eddy Simulation studies of the effects of alignment and wind farm length  

E-Print Network [OSTI]

Large eddy simulations of wind farms are performed to study the effects of wind turbine row alignment with respect to the incoming flow direction. Various wind farms with fixed stream-wise spacing (7.85 rotor diameters) and varying lateral displacements and span-wise turbine spacings are considered, for a fixed inflow direction. Simulations show that, contrary to common belief, a perfectly staggered (checker-board) configuration does not necessarily give the highest average power output. Instead, the highest mean wind farm power output is found to depend on several factors, the most important one being the alignment that leads to minimization of wake effects from turbines in several upstream rows. This alignment typically occurs at significantly smaller angles than those corresponding to perfect staggering. The observed trends have implications for wind farm designs, especially in sites with a well-defined prevailing wind direction.

Stevens, Richard J A M; Meneveau, Charles

2014-01-01T23:59:59.000Z

40

Temporal structure of aggregate power fluctuations in large-eddy simulations of extended wind-farms  

E-Print Network [OSTI]

Fluctuations represent a major challenge for the incorporation of electric power from large wind-farms into power grids. Wind farm power output fluctuates strongly in time, over various time scales. Understanding these fluctuations, especially their spatio-temporal characteristics, is particularly important for the design of backup power systems that must be readily available in conjunction with wind-farms. In this work we analyze the power fluctuations associated with the wind-input variability at scales between minutes to several hours, using large eddy simulations (LES) of extended wind-parks, interacting with the atmospheric boundary layer. LES studies enable careful control of parameters and availability of wind-velocities simultaneously across the entire wind-farm. The present study focuses on neutral atmospheric conditions and flat terrain, using actuator-disk representations of the individual wind-turbines. We consider power from various aggregates of wind-turbines such as the total average power sign...

Stevens, Richard J A M

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "large eddy simulation" 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

High-Resolution Large-Eddy Simulations of Scalar Transport in Atmospheric Boundary Layer Flow over Complex Terrain  

E-Print Network [OSTI]

of Electric Power Industry, Chiba, Japan FOTINI KATOPODES CHOW Department of Civil and Environmental to the choice of numerical simulation parameters than is typically needed for mean wind field predictions. Large-eddy simulation is used in a mesoscale setting, providing modeling advantages through the use of robust turbulence

Chow, Fotini Katopodes

42

Large-Eddy Simulations of Zero-Net-Mass-Flux Jet Based Separation Control in a Canonical Separated  

E-Print Network [OSTI]

Large-Eddy Simulations of Zero-Net-Mass-Flux Jet Based Separation Control in a Canonical Separated by Mittal et al1 for investigating active separation control using zero-net-mass-flux jets. Large. Zero-net-mass-flux forcing of the separated flow at the superharmonics of this baseline lock

Mittal, Rajat

43

A concurrent precursor inflow method for Large Eddy Simulations and applications to finite length wind farms  

E-Print Network [OSTI]

In order to enable simulations of developing wind turbine array boundary layers with highly realistic inflow conditions a concurrent precursor method for Large Eddy Simulations is proposed. In this method we consider two domains simultaneously, i.e. in one domain a turbulent Atmospheric Boundary Layer (ABL) without wind turbines is simulated in order to generate the turbulent inflow conditions for a second domain in which the wind turbines are placed. The benefit of this approach is that a) it avoids the need for large databases in which the turbulent inflow conditions are stored and the correspondingly slow I/O operations and b) we are sure that the simulations are not negatively affected by statically swept fixed inflow fields or synthetic fields lacking the proper ABL coherent structures. Sample applications are presented, in which, in agreement with field data a strong decrease of the power output of downstream wind-turbines with respect to the first row of wind-turbines is observed for perfectly aligned ...

Stevens, Richard J A M; Meneveau, Charles

2014-01-01T23:59:59.000Z

44

Simulations of an offshore wind farm using large eddy simulation and a torque-controlled actuator disc model  

E-Print Network [OSTI]

We present here a computational fluid dynamics (CFD) simulation of Lillgrund offshore wind farm, which is located in the {\\O}resund Strait between Sweden and Denmark. The simulation combines a dynamic representation of wind turbines embedded within a Large-Eddy Simulation CFD solver, and uses hr-adaptive meshing to increase or decrease mesh resolution where required. This allows the resolution of both large scale flow structures around the wind farm, and local flow conditions at individual turbines; consequently, the response of each turbine to local conditions can be modelled, as well as the resulting evolution of the turbine wakes. This paper provides a detailed description of the turbine model which simulates interactions between the wind, turbine rotors, and turbine generators by calculating the forces on the rotor, the body forces on the air, and instantaneous power output. This model was used to investigate a selection of key wind speeds and directions, investigating cases where a row of turbines would ...

Creech, Angus; Maguire, A Eoghan

2014-01-01T23:59:59.000Z

45

A consistent approach to large eddy simulation using adaptive mesh refinement  

SciTech Connect (OSTI)

The large eddy simulation of turbulent flows is discussed with particular attention paid to the issue of commutation of differentiation and filtering. Multi-level adaptive mesh refinement is proposed as a means of mostly avoiding commutation errors where increased grid resolution is required to capture key flow features. The strategy is to employ multiple uniform grids in a nested hierarchy using a constant-width filter for each grid. It is shown that commutivity of fine and coarse grid filters must be enforced in order to consistently relate variables at different refinement levels. Methods for treating fine grid boundaries and walls are also discussed. It is shown that errors associated with boundary treatments are small and localized.

Cook, A.W.

1999-09-01T23:59:59.000Z

46

Large eddy simulation of forced ignition of an annular bluff-body burner  

SciTech Connect (OSTI)

The optimization of the ignition process is a crucial issue in the design of many combustion systems. Large eddy simulation (LES) of a conical shaped bluff-body turbulent nonpremixed burner has been performed to study the impact of spark location on ignition success. This burner was experimentally investigated by Ahmed et al. [Combust. Flame 151 (2007) 366-385]. The present work focuses on the case without swirl, for which detailed measurements are available. First, cold-flow measurements of velocities and mixture fractions are compared with their LES counterparts, to assess the prediction capabilities of simulations in terms of flow and turbulent mixing. Time histories of velocities and mixture fractions are recorded at selected spots, to probe the resolved probability density function (pdf) of flow variables, in an attempt to reproduce, from the knowledge of LES-resolved instantaneous flow conditions, the experimentally observed reasons for success or failure of spark ignition. A flammability map is also constructed from the resolved mixture fraction pdf and compared with its experimental counterpart. LES of forced ignition is then performed using flamelet fully detailed tabulated chemistry combined with presumed pdfs. Various scenarios of flame kernel development are analyzed and correlated with typical flow conditions observed in this burner. The correlations between, velocities and mixture fraction values at the sparking time and the success or failure of ignition, are then further discussed and analyzed. (author)

Subramanian, V.; Domingo, P.; Vervisch, L. [CORIA-CNRS and INSA de Rouen, Technopole du Madrillet, BP 8, 76801 Saint-Etienne-du-Rouvray (France)

2010-03-15T23:59:59.000Z

47

Multi-Dimensional Broadband IR Radiative Forcing of Marine Stratocumulus in a Large Eddy Simulation Model  

SciTech Connect (OSTI)

In order to address the interactive and evolutionary nature of the cloud-radiation interaction, we have coupled to a Large Eddy Simulation (LES) model the sophisticated multi-dimensional radiative transfer (MDRT) scheme of Evans (Spherical Harmonics Discrete Ordinate Method; 1998). Because of computational expense, we are at this time only able to run 2D experiments. Preliminary runs consider only the broadband longwave component, in large part because IR cloud top cooling is the significant forcing mechanism for marine stratocumulus. Little difference is noted in the evolution of unbroken stratocumulus between three-hour runs using MDRT and independent pixel approximation (IPA) for 2D domains of 50 km in the horizontal and 1.5 km in the vertical. Local heating rates differ slightly near undulating regions of cloud top, and a slight bias in mean heating rate from 1 to 3 h is present, yet the differences are never strong enough to result in a pronounced evolutionary bias in typical boundary layer metrics (e.g. inversion height, vertical velocity variance, TKE). Longer integration times may eventually produce a physical response to the bias in radiative cooling rates. A low-CCN case, designed to produce significant drizzle and induce cloud breakup does show subtle differences between MDRT and IPA. Over the course of the 6 hour simulations, entrainment is slightly less in the MDRT case, and the transition to the surface-based trade cumulus regime is delayed. Mean cooling rates appear systematically weaker in the MDRT case, indicative of a less energetic PBL and reflected in profiles of vertical velocity variance and TKE.

Mechem, David B.; Ovtchinnikov, Mikhail; Kogan, Y. L.; Davis, Anthony B; Cahalan, Robert F.; Takara, Ezra E.; Ellingson, Robert G.

2002-06-03T23:59:59.000Z

48

Large-eddy simulation of turbulent cavitating flow in a micro channel  

SciTech Connect (OSTI)

Large-eddy simulations (LES) of cavitating flow of a Diesel-fuel-like fluid in a generic throttle geometry are presented. Two-phase regions are modeled by a parameter-free thermodynamic equilibrium mixture model, and compressibility of the liquid and the liquid-vapor mixture is taken into account. The Adaptive Local Deconvolution Method (ALDM), adapted for cavitating flows, is employed for discretizing the convective terms of the Navier-Stokes equations for the homogeneous mixture. ALDM is a finite-volume-based implicit LES approach that merges physically motivated turbulence modeling and numerical discretization. Validation of the numerical method is performed for a cavitating turbulent mixing layer. Comparisons with experimental data of the throttle flow at two different operating conditions are presented. The LES with the employed cavitation modeling predicts relevant flow and cavitation features accurately within the uncertainty range of the experiment. The turbulence structure of the flow is further analyzed with an emphasis on the interaction between cavitation and coherent motion, and on the statistically averaged-flow evolution.

Egerer, Christian P., E-mail: christian.egerer@aer.mw.tum.de; Hickel, Stefan; Schmidt, Steffen J.; Adams, Nikolaus A. [Institute of Aerodynamics and Fluid Mechanics, Technische Universität München, Boltzmannstr. 15, 85748 Garching bei München (Germany)

2014-08-15T23:59:59.000Z

49

Large eddy simulation/conditional moment closure modeling of swirl-stabilized non-premixed flames with local extinction  

E-Print Network [OSTI]

of Engineering University of Cambridge, Cambridge CB2 1PZ, United Kingdom Tel: +44 1223 332690, Fax: +44 1223 332662 Email: hz283@cam.ac.uk Colloquium topic: 5. Turbulent flames Alternative Colloquium topic: 11. IC engine and gas turbine combustion... mm+10) ? (2.2 words/mm) ? (1 column) + (12 words in caption) = 143 Total = 5966 words Supplemental Material: none Color reproduction: no (color figures are to be printed in gray scale)   1 Large eddy simulation/conditional moment closure...

Zhang, Huangwei; Garmory, Andrew; Cavaliere, Davide E.; Mastorakos, Epaminondas

2014-06-25T23:59:59.000Z

50

Numerical experiments with assimilation of the mean and unresolved meteorological conditions into large-eddy simulation model  

E-Print Network [OSTI]

Micrometeorology, city comfort, land use management and air quality monitoring increasingly become important environmental issues. To serve the needs, meteorology needs to achieve a serious advance in representation and forecast on micro-scales (meters to 100 km) called meteorological terra incognita. There is a suitable numerical tool, namely, the large-eddy simulation modelling (LES) to support the development. However, at present, the LES is of limited utility for applications. The study addresses two problems. First, the data assimilation problem on micro-scales is investigated as a possibility to recover the turbulent fields consistent with the mean meteorological profiles. Second, the methods to incorporate of the unresolved surface structures are investigated in a priopi numerical experiments. The numerical experiments demonstrated that the simplest nudging or Newtonian relaxation technique for the data assimilation is applicable on the turbulence scales. It is also shown that the filtering property of...

Esau, Igor

2010-01-01T23:59:59.000Z

51

Visualization and analysis of eddies in a global ocean simulation  

SciTech Connect (OSTI)

Eddies at a scale of approximately one hundred kilometers have been shown to be surprisingly important to understanding large-scale transport of heat and nutrients in the ocean. Due to difficulties in observing the ocean directly, the behavior of eddies below the surface is not very well understood. To fill this gap, we employ a high-resolution simulation of the ocean developed at Los Alamos National Laboratory. Using large-scale parallel visualization and analysis tools, we produce three-dimensional images of ocean eddies, and also generate a census of eddy distribution and shape averaged over multiple simulation time steps, resulting in a world map of eddy characteristics. As expected from observational studies, our census reveals a higher concentration of eddies at the mid-latitudes than the equator. Our analysis further shows that mid-latitude eddies are thicker, within a range of 1000-2000m, while equatorial eddies are less than 100m thick.

Williams, Sean J [Los Alamos National Laboratory; Hecht, Matthew W [Los Alamos National Laboratory; Petersen, Mark [Los Alamos National Laboratory; Strelitz, Richard [Los Alamos National Laboratory; Maltrud, Mathew E [Los Alamos National Laboratory; Ahrens, James P [Los Alamos National Laboratory; Hlawitschka, Mario [UC DAVIS; Hamann, Bernd [UC DAVIS

2010-10-15T23:59:59.000Z

52

Using Mesoscale Weather Model Output as Boundary Conditions for Atmospheric Large-Eddy Simulations and Wind-Plant Aerodynamic Simulations (Presentation)  

SciTech Connect (OSTI)

Wind plant aerodynamics are directly affected by the microscale weather, which is directly influenced by the mesoscale weather. Microscale weather refers to processes that occur within the atmospheric boundary layer with the largest scales being a few hundred meters to a few kilometers depending on the atmospheric stability of the boundary layer. Mesoscale weather refers to large weather patterns, such as weather fronts, with the largest scales being hundreds of kilometers wide. Sometimes microscale simulations that capture mesoscale-driven variations (changes in wind speed and direction over time or across the spatial extent of a wind plant) are important in wind plant analysis. In this paper, we present our preliminary work in coupling a mesoscale weather model with a microscale atmospheric large-eddy simulation model. The coupling is one-way beginning with the weather model and ending with a computational fluid dynamics solver using the weather model in coarse large-eddy simulation mode as an intermediary. We simulate one hour of daytime moderately convective microscale development driven by the mesoscale data, which are applied as initial and boundary conditions to the microscale domain, at a site in Iowa. We analyze the time and distance necessary for the smallest resolvable microscales to develop.

Churchfield, M. J.; Michalakes, J.; Vanderwende, B.; Lee, S.; Sprague, M. A.; Lundquist, J. K.; Moriarty, P. J.

2013-10-01T23:59:59.000Z

53

Applications of large eddy simulation methods to gyrokinetic turbulence A. Ban Navarro, B. Teaca, F. Jenko, G. W. Hammett, T. Happel, and ASDEX Upgrade Team  

E-Print Network [OSTI]

Applications of large eddy simulation methods to gyrokinetic turbulence A. Bañón Navarro, B. Teaca~non Navarro,1,a) B. Teaca,2,3,4 F. Jenko,1,4 G. W. Hammett,4,5 T. Happel,1 and ASDEX Upgrade Team1 1 Max

Hammett, Greg

54

Large-eddy simulation/probability density function modeling of a non-premixed CO/H2  

E-Print Network [OSTI]

;applicable to practical devices such as gas turbine combustors and internal combustion engines [2­ 4]. In LESLarge-eddy simulation/probability density function modeling of a non-premixed CO/H2 temporally-by-exchange with the mean (IEM) mix- ing model (with molecular transport) are solved by the highly-scalable NGA/HPDF codes

55

Selective large-eddy simulation of hypersonic flows. Procedure to activate the filtering in unresolved regions only  

E-Print Network [OSTI]

A new method for the localization of the regions where the turbulent fluctuations are unresolved is applied to the large-eddy simulation (LES) of a compressible turbulent jet with an initial Mach number equal to 5. The localization method used is called selective LES and is based on the exploitation of a scalar probe function f which represents the magnitude of the stretching-tilting term of the vorticity equation normalized with the enstrophy (Tordella et al. 2007). For a fully developed turbulent field of fluctuations, statistical analysis shows that the probability that f is larger than 2 is almost zero, and, for any given threshold, it is larger if the flow is under-resolved. By computing the spatial field of f in each instantaneous realization of the simulation it is possible to locate the regions where the magnitude of the normalized vortical stretching-tilting is anomalously high. The sub-grid model is then introduced into the governing equations in such regions only. The results of the selective LES s...

Tordella, D; Massaglia, S; Mignone, A

2012-01-01T23:59:59.000Z

56

Transitions of cloud-topped marine boundary layers characterized by AIRS, MODIS, and a large eddy simulation model  

SciTech Connect (OSTI)

Cloud top entrainment instability (CTEI) is a hypothesized positive feedback between entrainment mixing and evaporative cooling near the cloud top. Previous theoretical and numerical modeling studies have shown that the persistence or breakup of marine boundary layer (MBL) clouds may be sensitive to the CTEI parameter. Collocated thermodynamic profile and cloud observations obtained from the Atmospheric Infrared Sounder (AIRS) and Moderate Resolution Imaging Spectroradiometer (MODIS) instruments are used to quantify the relationship between the CTEI parameter and the cloud-topped MBL transition from stratocumulus to trade cumulus in the northeastern Pacific Ocean. Results derived from AIRS and MODIS are compared with numerical results from the UCLA large eddy simulation (LES) model for both well-mixed and decoupled MBLs. The satellite and model results both demonstrate a clear correlation between the CTEI parameter and MBL cloud fraction. Despite fundamental differences between LES steady state results and the instantaneous snapshot type of observations from satellites, significant correlations for both the instantaneous pixel-scale observations and the long-term averaged spatial patterns between the CTEI parameter and MBL cloud fraction are found from the satellite observations and are consistent with LES results. This suggests the potential of using AIRS and MODIS to quantify global and temporal characteristics of the cloud-topped MBL transition.

Yue, Qing; Kahn, Brian; Xiao, Heng; Schreier, Mathias; Fetzer, E. J.; Teixeira, J.; Suselj, Kay

2013-08-16T23:59:59.000Z

57

Investigation of two industrial developmental injectors using Large Eddy Simulation and ProperOrthogonal Decomposition  

E-Print Network [OSTI]

of the two injectors in both inert and reactive situations. The different codes and models are described in Chapter 3 of Ref. [1] and specific details for each simulation are given in the two following sections. 3.1 Injector A An inert LES simulation... and exhibits frequency peaks at 96.4 Hz, 474.3 Hz, 1035 Hz, 1459 Hz (strongest peak), 1603 Hz, 3507 Hz and 5102 Hz among others. Figure 4.6 shows the previous spectra in log-log scale to give an alternative perspective. 4.1.3 Proper Orthogonal Decomposition...

Ayache, Simon

2012-09-03T23:59:59.000Z

58

Quantifying the sensitivity of wind farm performance to array layout options using large-eddy simulation  

E-Print Network [OSTI]

and is coupled with an actuator line model to simulate the effects of the rotating wind turbine blades. A control that is capable of resolving wind turbine blades as rotat- ing actuator lines (not fixed disks) and does not rely by the spacing between wind turbines (along and across the prevailing wind direction) and by their alignment

59

A Large Eddy Simulation of Turbulent Compressible Convection: Differential Rotation in the Solar Convection Zone  

E-Print Network [OSTI]

We present results of two simulations of the convection zone, obtained by solving the full hydrodynamic equations in a section of a spherical shell. The first simulation has cylindrical rotation contours (parallel to the rotation axis) and a strong meridional circulation, which traverses the entire depth. The second simulation has isorotation contours about mid-way between cylinders and cones, and a weak meridional circulation, concentrated in the uppermost part of the shell. We show that the solar differential rotation is directly related to a latitudinal entropy gradient, which pervades into the deep layers of the convection zone. We also offer an explanation of the angular velocity shear found at low latitudes near the top. A non-zero correlation between radial and zonal velocity fluctuations produces a significant Reynolds stress in that region. This constitutes a net transport of angular momentum inwards, which causes a slight modification of the overall structure of the differential rotation near the top. In essence, the {\\it thermodynamics controls the dynamics through the Taylor-Proudman momentum balance}. The Reynolds stresses only become significant in the surface layers, where they generate a weak meridional circulation and an angular velocity `bump'.

Francis J. Robinson; Kwing L. Chan

2000-11-21T23:59:59.000Z

60

Large-Eddy Simulation of a Supersonic Inlet-Isolator Heeseok Koo  

E-Print Network [OSTI]

in a dual-mode scramjet engine that provides stable compressed flow to the combustor. However in the design of robust scramjet engines. Here, the predictive capability of the large ramjet engines are vital for the realization of hypersonic flight. Scramjets are relatively simple

Raman, Venkat

Note: This page contains sample records for the topic "large eddy simulation" 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

Assessment of combustion noise in a premixed swirled combustor via Large-Eddy Simulation  

E-Print Network [OSTI]

­5] as well as to more complex cases such as gas turbine combustors [6]. Computational techniques must be large enough to include the sources of noise as well as part of the acoustic near field [7 Acoustic analogy Direct computation Hybrid computation a b s t r a c t Today, much of the current effort

Nicoud, Franck

62

Large Eddy Simulation of PBL Stratocumulus: Comparison of Multi-Dimensional and IPA Longwave Radiative Forcing  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and Interfaces Sample6, 2011 CERN 73-11Large area avalanche

63

Large-Eddy Simulation for Green Energy and Propulsion Systems | Argonne  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and Interfaces Sample6, 2011 CERN 73-11Large areaLargefor High

64

Large eddy simulation of soot formation in a turbulent non-premixed jet flame  

SciTech Connect (OSTI)

A recently developed subgrid model for soot dynamics [H. El-Asrag, T. Lu, C.K. Law, S. Menon, Combust. Flame 150 (2007) 108-126] is used to study the soot formation in a non-premixed turbulent flame. The model allows coupling between reaction, diffusion and soot (including soot diffusion and thermophoretic forces) processes in the subgrid domain without requiring ad hoc filtering or model parameter adjustments. The combined model includes the entire process, from the initial phase, when the soot nucleus diameter is much smaller than the mean free path, to the final phase, after coagulation and aggregation, where it can be considered in the continuum regime. A relatively detailed but reduced kinetics for ethylene-air is used to simulate an experimentally studied non-premixed ethylene/air jet diffusion flame. Acetylene is used as a soot precursor species. The soot volume fraction order of magnitude, the location of its maxima, and the soot particle size distribution are all captured reasonably. Along the centerline, an initial region dominated by nucleation and surface growth is established followed by an oxidation region. The diffusion effect is found to be most important in the nucleation regime, while the thermophoretic forces become more influential downstream of the potential core in the oxidation zone. The particle size distribution shows a log-normal distribution in the nucleation region, and a more Gaussian like distribution further downstream. Limitations of the current approach and possible solution strategies are also discussed. (author)

El-Asrag, Hossam [Center For Turbulence Research, Stanford, CA 94305 (United States); Menon, Suresh [School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

2009-02-15T23:59:59.000Z

65

Quantification of errors in large-eddy simulations of a spatially evolving mixing layer using polynomial chaos  

SciTech Connect (OSTI)

A stochastic approach based on generalized polynomial chaos (gPC) is used to quantify the error in large-eddy simulation (LES) of a spatially evolving mixing layer flow and its sensitivity to different simulation parameters, viz., the grid stretching in the streamwise and lateral directions and the subgrid-scale (SGS) Smagorinsky model constant (C{sub S}). The error is evaluated with respect to the results of a highly resolved LES and for different quantities of interest, namely, the mean streamwise velocity, the momentum thickness, and the shear stress. A typical feature of the considered spatially evolving flow is the progressive transition from a laminar regime, highly dependent on the inlet conditions, to a fully developed turbulent one. Therefore, the computational domain is divided in two different zones (inlet dependent and fully turbulent) and the gPC error analysis is carried out for these two zones separately. An optimization of the parameters is also carried out for both these zones. For all the considered quantities, the results point out that the error is mainly governed by the value of the C{sub S} constant. At the end of the inlet-dependent zone, a strong coupling between the normal stretching ratio and the C{sub S} value is observed. The error sensitivity to the parameter values is significantly larger in the inlet-dependent upstream region; however, low-error values can be obtained in this region for all the considered physical quantities by an ad hoc tuning of the parameters. Conversely, in the turbulent regime the error is globally lower and less sensitive to the parameter variations, but it is more difficult to find a set of parameter values leading to optimal results for all the analyzed physical quantities. A similar analysis is also carried out for the dynamic Smagorinsky model, by varying the grid stretching ratios. Comparing the databases generated with the different subgrid-scale models, it is possible to observe that the error cost function computed for the streamwise velocity and for the momentum thickness is not significantly sensitive to the used SGS closure. Conversely, the prediction of the shear stress is much more accurate when using a dynamic subgrid-scale model and the variance of the error is lower in magnitude.

Meldi, M.; Sagaut, P. [Institut Jean Le Rond d'Alembert, UMR 7190, Universite Pierre et Marie Curie - Paris 6, F-75005 Paris (France); Salvetti, M. V. [Dipartimento di Ingegneria Aerospaziale, Universita di Pisa, I-56122 Pisa (Italy)

2012-03-15T23:59:59.000Z

66

Validation/Uncertainty Quantification for Large Eddy Simulations of the heat flux in the Tangentially Fired Oxy-Coal Alstom Boiler Simulation Facility  

SciTech Connect (OSTI)

The objective of this task is to produce predictive capability with quantified uncertainty bounds for the heat flux in commercial-scale, tangentially fired, oxy-coal boilers. Validation data came from the Alstom Boiler Simulation Facility (BSF) for tangentially fired, oxy-coal operation. This task brings together experimental data collected under Alstom’s DOE project for measuring oxy-firing performance parameters in the BSF with this University of Utah project for large eddy simulation (LES) and validation/uncertainty quantification (V/UQ). The Utah work includes V/UQ with measurements in the single-burner facility where advanced strategies for O2 injection can be more easily controlled and data more easily obtained. Highlights of the work include: • Simulations of Alstom’s 15 megawatt (MW) BSF, exploring the uncertainty in thermal boundary conditions. A V/UQ analysis showed consistency between experimental results and simulation results, identifying uncertainty bounds on the quantities of interest for this system (Subtask 9.1) • A simulation study of the University of Utah’s oxy-fuel combustor (OFC) focused on heat flux (Subtask 9.2). A V/UQ analysis was used to show consistency between experimental and simulation results. • Measurement of heat flux and temperature with new optical diagnostic techniques and comparison with conventional measurements (Subtask 9.3). Various optical diagnostics systems were created to provide experimental data to the simulation team. The final configuration utilized a mid-wave infrared (MWIR) camera to measure heat flux and temperature, which was synchronized with a high-speed, visible camera to utilize two-color pyrometry to measure temperature and soot concentration. • Collection of heat flux and temperature measurements in the University of Utah’s OFC for use is subtasks 9.2 and 9.3 (Subtask 9.4). Several replicates were carried to better assess the experimental error. Experiments were specifically designed for the generation of high-fidelity data from a turbulent oxy-coal flame for the validation of oxy-coal simulation models. Experiments were also conducted on the OFC to determine heat flux profiles using advanced strategies for O2 injection. This is important when considering retrofit of advanced O2 injection in retrofit configurations.

Smith, P.J.; Eddings, E.G.; Ring, T.; Thornock, J.; Draper, T.; Isaac, B.; Rezeai, D.; Toth, P.; Wu, Y.; Kelly, K.

2014-08-01T23:59:59.000Z

67

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

SciTech Connect (OSTI)

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

68

NREL researchers are the first to use a high-performance com-puting tool for a large-eddy simulation of an entire wind plant.  

E-Print Network [OSTI]

Denmark and Sweden and compared results with more than a year's worth of plant data.The simulated power at least 50% wastepaper, including 10% post consumer waste. NREL Develops Simulations forWind Plant Power-eddy simulation of an entire wind plant. Researchers at the National Renewable Energy Laboratory's (NREL) National

69

An evaluation of the assumed beta probability density function subgrid-scale model for large eddy simulation of nonpremixed, turbulent combustion with heat release  

SciTech Connect (OSTI)

The assumed beta distribution model for the subgrid-scale probability density function (PDF) of the mixture fraction in large eddy simulation of nonpremixed, turbulent combustion is tested, a priori, for a reacting jet having significant heat release (density ratio of 5). The assumed beta distribution is tested as a model for both the subgrid-scale PDF and the subgrid-scale Favre PDF of the mixture fraction. The beta model is successful in approximating both types of PDF but is slightly more accurate in approximating the normal (non-Favre) PDF. To estimate the subgrid-scale variance of mixture fraction, which is required by the beta model, both a scale similarity model and a dynamic model are used. Predictions using the dynamic model are found to be more accurate. The beta model is used to predict the filtered value of a function chosen to resemble the reaction rate. When no model is used, errors in the predicted value are of the same order as the actual value. The beta model is found to reduce this error by about a factor of two, providing a significant improvement. (c) 2000 American Institute of Physics.

Wall, Clifton [Center for Turbulence Research, Stanford University, Stanford, California 94305 (United States)] [Center for Turbulence Research, Stanford University, Stanford, California 94305 (United States); Boersma, Bendiks Jan [Center for Turbulence Research, Stanford University, Stanford, California 94305 (United States)] [Center for Turbulence Research, Stanford University, Stanford, California 94305 (United States); Moin, Parviz [Center for Turbulence Research, Stanford University, Stanford, California 94305 (United States)] [Center for Turbulence Research, Stanford University, Stanford, California 94305 (United States)

2000-10-01T23:59:59.000Z

70

A Comparison of the Dynamic Wake Meandering Model, Large-Eddy...  

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

Wake Meandering Model, Large-Eddy Simulation, and Field Data at the Egmond aan Zee Offshore Wind Plant Preprint M.J. Churchfield and P.J. Moriarty National Renewable Energy...

71

Multiscale eddy simulation for moist atmospheric convection: Preliminary investigation  

SciTech Connect (OSTI)

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

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

2014-08-15T23:59:59.000Z

72

Eddy current NDE performance demonstrations using simulation tools  

SciTech Connect (OSTI)

To carry out performance demonstrations of the Eddy-Current NDE processes applied on French nuclear power plants, EDF studies the possibility of using simulation tools as an alternative to measurements on steam generator tube mocks-up. This paper focuses on the strategy led by EDF to assess and use code{sub C}armel3D and Civa, on the case of Eddy-Current NDE on wears problem which may appear in the U-shape region of steam generator tubes due to the rubbing of anti-vibration bars.

Maurice, L. [EDF - CEIDRE, 2 rue Ampere, 93206 Saint-Denis Cedex 1 (France); Costan, V.; Guillot, E.; Thomas, P. [EDF - R and D, THEMIS, 1, avenue du General de Gaulle, 92141 Clamart (France)

2013-01-25T23:59:59.000Z

73

Development and assessment of a coupled strategy for conjugate heat transfer with Large Eddy Simulation: Application to a cooled turbine blade  

E-Print Network [OSTI]

parameters. The coupled tool is then applied to a cooled turbine blade model where results demonstrate both walls is an important phenomenon in combustion chambers and a main design constraint in gas turbines Simulation: Application to a cooled turbine blade F. Duchaine a,*, A. Corpron b , L. Pons b , V. Moureau b

Nicoud, Franck

74

Adaptive Detached Eddy Simulation of a High Lift Wing with Active...  

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

and slat support). Adaptive Detached Eddy Simulation of a High Lift Wing with Active Flow Control PI Name: Kenneth Jansen PI Email: jansenke@colorado.edu Institution:...

75

Simulation for the assessment of wall thinning using eddy current method  

SciTech Connect (OSTI)

A pipe with protective cladding and insulation was simplified to a four-layered structure when the diameter of a pipe is large enough, and analytical solutions for sinusoidal and pulsed wave excitation were derived. Simulation implemented by using the analytical solutions showed that sinusoidal excitation is not appropriate for the monitoring of inner thinning, while pulsed eddy current method can be used to measure wall-thickness regardless of inner or outer thinning by using the decay rate of log(Bz) as a particular parameter to evaluate wall thickness.

Cheng, W.; Komura, I. [NDE Center, Japan Power Engineering and Inspection Corporation, Yokohama 230-0044 (Japan)

2011-06-23T23:59:59.000Z

76

Inflow turbulence generation for eddy-resolving simulations of turbomachinery flows  

E-Print Network [OSTI]

A simple variant of recycling and rescaling method to generate inflow turbulence using unstructured grid CFD codes is presented. The method has been validated on large eddy simulation of spatially developing flat plate turbulent boundary layer. The proposed rescaling algorithm is based on the momentum thickness which is more robust and essentially obviates the need of finding the edge of the turbulent boundary layer in unstructured grid codes. Extension of this algorithm to hybrid RANS/LES type of approaches and for wall-bounded turbomachinery flows is also discussed. Results from annular diffuser with different inflow boundary layer characteristics is presented as an example application to show the utility of such an algorithm.

Arolla, Sunil K

2014-01-01T23:59:59.000Z

77

Large-scale eddies and their role in entrainment in turbulent jets and wakes Jimmy Philip and Ivan Marusic  

E-Print Network [OSTI]

Large-scale eddies and their role in entrainment in turbulent jets and wakes Jimmy Philip and Ivan jets and wakes Jimmy Philipa) and Ivan Marusicb) Department of Mechanical Engineering, University

Marusic, Ivan

78

Eddy Fluxes and Sensitivity of the Water Cycle to Spatial Resolution in Idealized Regional Aquaplanet Model Simulations  

SciTech Connect (OSTI)

A multi-scale moisture budget analysis is used to identify the mechanisms responsible for the sensitivity of the water cycle to spatial resolution using idealized regional aquaplanet simulations. In the higher resolution simulations, moisture transport by eddies fluxes dry the boundary layer enhancing evaporation and precipitation. This effect of eddies, which is underestimated by the physics parameterizations in the low-resolution simulations, is found to be responsible for the sensitivity of the water cycle both directly, and through its upscale effect, on the mean circulation. Correlations among moisture transport by eddies at adjacent ranges of scales provides the potential for reducing this sensitivity by representing the unresolved eddies by their marginally resolved counterparts.

Hagos, Samson M.; Leung, Lai-Yung R.; Gustafson, William I.; Singh, Balwinder

2014-02-28T23:59:59.000Z

79

Study of natural ventilation in buildings with large eddy simulation  

E-Print Network [OSTI]

With the discovery of many economic, environmental, and health problems in sealed and mechanically ventilated buildings, the concept of natural ventilation has been revived. "Buildings that breathe" have become more and ...

Jiang, Yi, 1972-

2002-01-01T23:59:59.000Z

80

Large Eddy Simulation (LES) Applied to Advanced Engine Combustion...  

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

B. Cuenot, CERFACS, France * Professor A. Dreizler, Technical University of Darmstadt, Germany * Professor B. Geurts, University of Twente, The Netherlands * Professor D. Haworth,...

Note: This page contains sample records for the topic "large eddy simulation" 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

Large Eddy Simulation (LES) Applied to Advanced Engine Combustion...  

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

3 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting ace007oefelein2013o.pdf More Documents & Publications...

82

Large Eddy Simulation of a Turbulent Buoyant Helium Philip Smith  

E-Print Network [OSTI]

.thornock@utah.edu ABSTRACT At the Institute for Clean and Secure Energy at the University of Utah we are focused on education agencies and private industry companies to promote rapid deployment of new technologies through the use to solve many industrially relevant problems such as industrial flares, oxy-coal combustion processes

Utah, University of

83

Large Eddy Simulation of Industrial Flares Philip Smith  

E-Print Network [OSTI]

At the Institute for Clean and Secure Energy at the University of Utah we are focused on education through and private industry companies to promote rapid deployment of new technologies through the use of high to solve many industrially relevant problems such as industrial flares, oxy-coal combustion processes

Utah, University of

84

Large Eddy Simulation (LES) Applied to Advanced Engine Combustion...  

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

over broad operating ranges) - Requirements for efficient and routine use of high-performance computing (HPC), development of both predictive and affordable models for advanced...

85

Large Eddy Simulation (LES) Applied to Advanced Engine Combustion...  

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

for engine combustion and emission control - Efficient and routine use of High-Performance-Computing (HPC) to establish optimal balance between predictive and affordable models...

86

Large Eddy Simulations of Jet Flow Interactions Within Rod Bundles  

E-Print Network [OSTI]

The present work investigates the turbulent jet flow mixing of downward impinging jets within a staggered rod bundle based on previous experimental work. The two inlet jets had Reynold's numbers of 11,160 and 6,250 and were chosen to coincide...

Salpeter, Nathaniel O.

2010-07-14T23:59:59.000Z

87

Large eddy simulation of turbulence within heat exchangers  

E-Print Network [OSTI]

be problematic if the turbulent energy is near the tubes natural frequency. However, as compared to the drag force exerted by the fluid, vortex shedding and turbulent buffeting are are of lesser significance than fluid elastic instability. Fluid elastic... on turbulent statistics. Is is widely accepted that there are four basic sources of cross-flow excitation in tube banks: vortex shedding, turbulent buffeting, fluid-elastic instability, and acoustic resonance (Grover et aL 1978). Vortex shedding is a...

Pruitt, John Myron

2012-06-07T23:59:59.000Z

88

Large Eddy Simulation (LES) Applied to Advanced Engine Combustion Research  

Broader source: Energy.gov [DOE]

2013 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting

89

Large Eddy Simulation (LES) Applied to Advanced Engine Combustion Research  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeatMulti-Dimensionalthe10 DOEWashington,LM-04-XXXX OfficeLand and FacilityThe

90

Large Eddy Simulations of Combustor Liner Flows | Argonne Leadership  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-SeriesFlickrinformationPostdocs space CombinedValues shown forShadeand

91

Sandia National Laboratories: Large eddy simulation of a lifted ethylene  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 -theErik Spoerke SSLS ExhibitIowa State UniversityFacilityLIMITS Liquidflame using a

92

Prediction of Small-Scale Cavitation in a High Speed Flow Over an Open Cavity Using Large Eddy  

E-Print Network [OSTI]

Prediction of Small-Scale Cavitation in a High Speed Flow Over an Open Cavity Using Large Eddy- gether with the cavitation models predict that inception occurs near the trailing edge similar in cavitation. 1 INTRODUCTION The problem of cavitation has been widely studied owing to its influence

Apte, Sourabh V.

93

Testing a theory for the effect of latitude on the persistence of eddy driven jets using CMIP3 simulations  

E-Print Network [OSTI]

between the eddies and the mean flow and yields a wider, less self sustaining jet. The results suggest

Barnes, Elizabeth A.

94

Large-scale simulations of reionization  

SciTech Connect (OSTI)

We use cosmological simulations to explore the large-scale effects of reionization. Since reionization is a process that involves a large dynamic range--from galaxies to rare bright quasars--we need to be able to cover a significant volume of the universe in our simulation without losing the important small scale effects from galaxies. Here we have taken an approach that uses clumping factors derived from small scale simulations to approximate the radiative transfer on the sub-cell scales. Using this technique, we can cover a simulation size up to 1280h{sup -1} Mpc with 10h{sup -1} Mpc cells. This allows us to construct synthetic spectra of quasars similar to observed spectra of SDSS quasars at high redshifts and compare them to the observational data. These spectra can then be analyzed for HII region sizes, the presence of the Gunn-Peterson trough, and the Lyman-{alpha} forest.

Kohler, Katharina; /JILA, Boulder /Fermilab; Gnedin, Nickolay Y.; /Fermilab; Hamilton, Andrew J.S.; /JILA, Boulder

2005-11-01T23:59:59.000Z

95

LARGE EDDY SIMULATION/EULERIAN PROBABILITY DENSITY FUNCTION APPROACH FOR SIMULATING HYDROGEN-ENRICHED GAS TURBINE  

E-Print Network [OSTI]

while the small-scale motions are modeled using sub-filter models. Since gas-turbine relevant combustion providing better input for the combustion models. Developing LES-based combustion models for stationary gas) based approach is used here to deal with the complexities of gas turbine combustion. In the PDF approach

Raman, Venkat

96

Natural Ventilation in Buildings: Measurement in a Wind Tunnel and Numerical Simulation with Large Eddy Simulation  

E-Print Network [OSTI]

save energy compared to mechanical ventilation systems. In building design the prediction save energy consumed by the heating, ventilating, and air- conditioning systems in a building. In a naturally ventilated building, air is driven in and out due to pressure differences produced by wind

Chen, Qingyan "Yan"

97

NREL Develops Simulations for Wind Plant Power and Turbine Loads (Fact Sheet)  

SciTech Connect (OSTI)

NREL researchers are the first to use a high-performance computing tool for a large-eddy simulation of an entire wind plant.

Not Available

2012-04-01T23:59:59.000Z

98

Large-scale Intelligent Transporation Systems simulation  

SciTech Connect (OSTI)

A prototype computer system has been developed which defines a high-level architecture for a large-scale, comprehensive, scalable simulation of an Intelligent Transportation System (ITS) capable of running on massively parallel computers and distributed (networked) computer systems. The prototype includes the modelling of instrumented ``smart`` vehicles with in-vehicle navigation units capable of optimal route planning and Traffic Management Centers (TMC). The TMC has probe vehicle tracking capabilities (display position and attributes of instrumented vehicles), and can provide 2-way interaction with traffic to provide advisories and link times. Both the in-vehicle navigation module and the TMC feature detailed graphical user interfaces to support human-factors studies. The prototype has been developed on a distributed system of networked UNIX computers but is designed to run on ANL`s IBM SP-X parallel computer system for large scale problems. A novel feature of our design is that vehicles will be represented by autonomus computer processes, each with a behavior model which performs independent route selection and reacts to external traffic events much like real vehicles. With this approach, one will be able to take advantage of emerging massively parallel processor (MPP) systems.

Ewing, T.; Canfield, T.; Hannebutte, U.; Levine, D.; Tentner, A.

1995-06-01T23:59:59.000Z

99

Simulation of Convection and Macrosegregation in a Large Steel Ingot  

E-Print Network [OSTI]

Simulation of Convection and Macrosegregation in a Large Steel Ingot J.P. GU and C. BECKERMANN Melt convection and macrosegregation in casting of a large steel ingot are numerically simulated. The simulation is based on a previously developed model for multicomponent steel solidification with melt convection

Beckermann, Christoph

100

ON THE EULERIAN LARGE EDDY SIMULATION OF DISPERSE PHASE FLOWS: AN ASYMPTOTIC PRESERVING SCHEME FOR  

E-Print Network [OSTI]

. These constraints are: 1/as the resulting sound speed is inversely proportional to the Stokes number, it is highly on the accurate description of both the continuous carrier phase, gaseous or liquid, and the discrete particulate

Paris-Sud XI, Université de

Note: This page contains sample records for the topic "large eddy simulation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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101

Massively Parallel Spectral Element Large Eddy Simulation of a Turbulent Channel Using Wall Models  

E-Print Network [OSTI]

Wall-bounded turbulent flows are prevalent in engineering and industrial applications. Walls greatly affect turbulent characteristics in many ways including production and propagation of turbulent stresses. While computational fluid dynamics can...

Rabau, Joshua I

2013-05-01T23:59:59.000Z

102

Large Eddy Simulation based Studies of Reacting and Non-reacting Transverse Jets in Supersonic Crossflow  

E-Print Network [OSTI]

-ignition and flame stability. To ensure e cient and robust combustion inside scramjet engines, fuel injection of these designs is necessary for the design of e cient scramjet engines. The focus of this work is to use detailed

Raman, Venkat

103

Turbulence prediction using the large eddy simulation method in staggered and inlined bundles  

E-Print Network [OSTI]

for the fruitful discussions and technical support they provided throughout the investigation. Discussions with Mr. Wael Ibrahim, Mr. SaeYul Lee and Mr. John Pruitt were also helpful for a better understanding of the intricacies of turbulence and computational...

Barsamian, Hagop Raffi

1994-01-01T23:59:59.000Z

104

Complex Effects in Large Eddy Simulation Limassol, September 20-24,2005  

E-Print Network [OSTI]

a requirement for combustion instability studies. 1 INTRODUCTION In the highly competitive field of power generation, gas turbines have gained an increasing role over the years. New emission regulations and growing

105

Large-Eddy Simulations of Perfectly-Expanded Supersonic Jets: Quality Assessment and Validation  

E-Print Network [OSTI]

but use an emulation procedure, with sources and sinks with zero net mass flux. This procedure gives the contributions of the different explicit models introduced in the calculation (artificial dissipation, subgrid

Mendez, Simon

106

LARGE EDDY SIMULATION FOR TURBULENT MHD FLOWS A. LABOVSKY AND C. TRENCHEA  

E-Print Network [OSTI]

problems such as plasma confinement, controlled thermonuclear fusion, liquid-metal cooling of nuclear

Trenchea, Catalin

107

Assessment of combustion noise in a premixed swirled combustor via Large-eddy simulation  

E-Print Network [OSTI]

, 4, 5] as well as to more complex cases such as gas turbine combustors. [6] Corresponding author. Ph methods such as LES or DNS can directly provide the acoustic field radiated by noise sources. The sources are still calculated by DNS or LES codes whereas the radiated sound is evaluated by acoustic codes

Boyer, Edmond

108

Numerical errors in the computation of subfilter scalar variance in large eddy simulations  

E-Print Network [OSTI]

Mechanics, The University of Texas at Austin, Austin, Texas 78712, USA 2 Center for Turbulence Research of specific model forms. Like other subfilter quantities, such as kinetic energy, subfilter variance can-rule manipulations used to derive convection, diffusion, and production terms associated with the square

Raman, Venkat

109

Large Eddy Simulation (LES) Applied to LTC/Diesel/Hydrogen Engine...  

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

10 DOE Vehicle Technologies and Hydrogen Programs Annual Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C. ace007oefelein2010o.pdf More Documents &...

110

Large-eddy simulation of evaporating spray in a coaxial combustor  

E-Print Network [OSTI]

on unstructured grids at conditions representative of gas-turbine combustors. Ã? 2009 The Combustion Institute of engineering applications; e.g., inter- nal combustion engines, liquid and solid propel- lant rocket motors, gas-turbine aircraft engines, cyclone combustors, and biomass gasifiers. The physics of such flows

Apte, Sourabh V.

111

Large-Eddy Simulation of Evaporating Spray in a Coaxial Combustor  

E-Print Network [OSTI]

of engineering applications; e.g. internal combustion engines, liquid and solid propellant rocket motors, gas-turbine representative of gas-turbine combustors. Key words: Sprays, LES, unstructured grids, particle-laden flows complex. In gas turbine combustors, for example, the liquid fuel jet undergoes primary and secondary

Mahesh, Krishnan

112

Large-Eddy Simulations of a Drizzling, Stratocumulus-Topped Marine Boundary  

E-Print Network [OSTI]

and Technology Yokahama, Japan Markus D. Petters Department of Atmospheric Science Colorado State University, Colorado Kozo Nakamura Frontier Research Center for Global Change Japan Agency for Marine-Earth Science on the global heat budget (Klein and Hartmann 1993). Evidence suggests they constitute a leading

Stevens, Bjorn

113

Large eddy simulations of premixed turbulent flame dynamics : combustion modeling, validation and analysis  

E-Print Network [OSTI]

High efficiency, low emissions and stable operation over a wide range of conditions are some of the key requirements of modem-day combustors. To achieve these objectives, lean premixed flames are generally preferred as ...

Kewlani, Gaurav

2014-01-01T23:59:59.000Z

114

Fidelity of Analytic Drop Size Distributions in Drizzling Stratiform Clouds Based on Large-Eddy Simulations  

E-Print Network [OSTI]

Cloud microphysical parameterizations and retrievals rely heavily on knowledge of the shape of drop size distributions (DSDs). Many investigations assume that DSDs in the entire or partial drop size range may be approximated ...

Kogan, Yefim L.; Kogan, Zena N.; Mechem, David B.

2009-08-01T23:59:59.000Z

115

Large eddy simulation of supersonic combustion with application to scramjet engines  

E-Print Network [OSTI]

[105] (a) Detail of noz- zle and combustor (b) Detail of combustor entrance and injector geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 7.2 Hydrogen mass fraction distribution on the combustor centreline . 185 7.3 Planes... of temperature and oxygen mole fraction experimental data down the axis of the SCHOLAR combustor . . . . . . . . . . . . . 186 7.4 Experimental pressure distributions for the upper (left) and lower (right) walls of the combustor, after 10 and 24 seconds...

Cocks, Peter

2011-07-12T23:59:59.000Z

116

Large-eddy Simulation of the Nighttime Stable Atmospheric Boundary Layer  

E-Print Network [OSTI]

by providing accurate vertical wind speed profiles. TurbineC-1 Schematic of vertical wind speed and density profiles in50,000 s) vertical profiles of wind speed for the moderately

Zhou, Bowen

2012-01-01T23:59:59.000Z

117

Large-Eddy Simulation of Pulverized Coal Jet Flame -Effect of Oxygen Concentration on NOx formation  

E-Print Network [OSTI]

than those by using other fossil fuels [1]. It is therefore important to develop clean coal technology for pulverized coal fired power plants, in order to control such emissions and to reduce the environmental impact. Regarding the reduction...

Muto, Masaya; Watanabe, Hiroaki; Kurose, Ryoichi; Komori, Satoru; Balusamy, Saravanan; Hochgreb, Simone

2015-01-01T23:59:59.000Z

118

Numerical Investigation of a Transverse Jet in a Supersonic Crossflow using Large Eddy Simulation  

E-Print Network [OSTI]

Density Thermal conductivity Ratio of specific heats µl Fluid viscosity µs Non linear artificial shear of the free stream supersonic flow by the transverse jet, a bow shock is also produced. It causes the upstream

Paris-Sud XI, Université de

119

Large Eddy Simulation (LES) Applied to LTC/Diesel/Hydrogen Engine  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeatMulti-Dimensionalthe10 DOEWashington,LM-04-XXXX OfficeLand and

120

Large Eddy Simulation (LES) Applied to LTC/Diesel/Hydrogen Engine  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeatMulti-Dimensionalthe10 DOEWashington,LM-04-XXXX OfficeLand andCombustion Research |

Note: This page contains sample records for the topic "large eddy simulation" 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

Large Eddy Simulation (LES) Applied to Low-Temperature and Diesel Engine  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeatMulti-Dimensionalthe10 DOEWashington,LM-04-XXXX OfficeLand andCombustion Research

122

Large Eddy Simulation of laser ignition and compressible reacting flow in a rocket-like  

E-Print Network [OSTI]

combustion devices. The technical needs for internal-combustion (IC) engines and aircraft combustors have in a rocket engine is a critical problem for combustion cham- ber design. Delayed ignition may lead to high without failure. The combustion initiation in rocket engines is usually based on pyrotechnic devices

Paris-Sud XI, Université de

123

Study of natural ventilation in buildings by large eddy simulation Yi Jiang and Qingyan Chen*  

E-Print Network [OSTI]

in buildings can create a comfortable and healthy indoor environment, and can save energy used constitutes a major part of the energy consumption in buildings. To reduce energy used by mechanical cooling is driven in and out of a building due to pressure differences, produced by wind and buoyancy forces

Chen, Qingyan "Yan"

124

Large-eddy Simulation of the Nighttime Stable Atmospheric Boundary Layer  

E-Print Network [OSTI]

coordinate and (b) wind and potential temperature at the up-coordinate and (b) wind and potential temperature at the up-Mean profiles of wind and potential temperature, turbulent

Zhou, Bowen

2012-01-01T23:59:59.000Z

125

LARGE EDDY SIMULATION AND MEASUREMENTS IN A TURBULENT ROTOR-STATOR FLOW  

E-Print Network [OSTI]

). The flow has significant industrial applications, such as internal gas- turbine flows and computer hard model is based on Spectral Vanishing Viscosity (SVV). The key particularity of this model

Paris-Sud XI, Université de

126

Neurosciences Eddie Smith  

E-Print Network [OSTI]

Ambulatory Care Thurston Bowles Neurosciences MBRB Carolina Inn Paul Green Graham Davis Lib Eddie Smith Field

Lieb, Jason

127

Diagnosis of Differences Between Stratiform Clouds Simulated by Large-Eddy Simulation and Single-Column Models  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed Newcatalyst phasesData FilesShape, Density,TiO2(110).DevelopmentDeviceDiagnosis

128

Effects of Sea-Salt Aerosols on Precipitation in Simulations of Shallow Cumulus  

E-Print Network [OSTI]

A suite of large-eddy simulations with size-resolving microphysical processes was performed in order to assess effects of sea-salt aerosols on precipitation process in trade cumulus. Simulations based on observations from ...

Kogan, Yefim L.; Mechem, David B.; Choi, Kityan

2012-02-01T23:59:59.000Z

129

PANS method of turbulence: simulation of high and low Reynolds number flows past a circular cylinder  

E-Print Network [OSTI]

cylinder are performed at ReD 140,000 and ReD 3900 using the PANS model. The high Reynolds number PANS results are compared with experimental results from Cantwell and Coles, Large Eddy Simulation results from Breuer, and Detached Eddy Simulation results...

Lakshmipathy, Sunil

2006-04-12T23:59:59.000Z

130

Eddy-resolving simulations of the Fimbul Ice Shelf cavity circulation: Basal melting and exchange with open ocean  

E-Print Network [OSTI]

that govern the heat supply to ice shelves in the Eastern Weddell Sea. The simulations confirm the low melt

Lilly, Jonathan

131

Large-scale simulations of complex physical systems  

SciTech Connect (OSTI)

Scientific computing has become a tool as vital as experimentation and theory for dealing with scientific challenges of the twenty-first century. Large scale simulations and modelling serve as heuristic tools in a broad problem-solving process. High-performance computing facilities make possible the first step in this process - a view of new and previously inaccessible domains in science and the building up of intuition regarding the new phenomenology. The final goal of this process is to translate this newly found intuition into better algorithms and new analytical results.In this presentation we give an outline of the research themes pursued at the Scientific Computing Laboratory of the Institute of Physics in Belgrade regarding large-scale simulations of complex classical and quantum physical systems, and present recent results obtained in the large-scale simulations of granular materials and path integrals.

Belic, A. [Scientific Computing Laboratory, Institute of Physics, Pregrevica 118, 11080 Belgrade (Serbia and Montenegro)

2007-04-23T23:59:59.000Z

132

Toward Improved Support for Loosely Coupled Large Scale Simulation Workflows  

SciTech Connect (OSTI)

High-performance computing (HPC) workloads are increasingly leveraging loosely coupled large scale simula- tions. Unfortunately, most large-scale HPC platforms, including Cray/ALPS environments, are designed for the execution of long-running jobs based on coarse-grained launch capabilities (e.g., one MPI rank per core on all allocated compute nodes). This assumption limits capability-class workload campaigns that require large numbers of discrete or loosely coupled simulations, and where time-to-solution is an untenable pacing issue. This paper describes the challenges related to the support of fine-grained launch capabilities that are necessary for the execution of loosely coupled large scale simulations on Cray/ALPS platforms. More precisely, we present the details of an enhanced runtime system to support this use case, and report on initial results from early testing on systems at Oak Ridge National Laboratory.

Boehm, Swen [ORNL] [ORNL; Elwasif, Wael R [ORNL] [ORNL; Naughton, III, Thomas J [ORNL; Vallee, Geoffroy R [ORNL] [ORNL

2014-01-01T23:59:59.000Z

133

Tidal Residual Eddies and their Effect on Water Exchange in Puget Sound  

SciTech Connect (OSTI)

Tidal residual eddies are one of the important hydrodynamic features in tidally dominant estuaries and coastal bays, and they could have significant effects on water exchange in a tidal system. This paper presents a modeling study of tides and tidal residual eddies in Puget Sound, a tidally dominant fjord-like estuary in the Pacific Northwest coast, using a three-dimensional finite-volume coastal ocean model. Mechanisms of vorticity generation and asymmetric distribution patterns around an island/headland were analyzed using the dynamic vorticity transfer approach and numerical experiments. Model results of Puget Sound show that a number of large twin tidal residual eddies exist in the Admiralty Inlet because of the presence of major headlands in the inlet. Simulated residual vorticities near the major headlands indicate that the clockwise tidal residual eddy (negative vorticity) is generally stronger than the anticlockwise eddy (positive vorticity) because of the effect of Coriolis force. The effect of tidal residual eddies on water exchange in Puget Sound and its sub-basins were evaluated by simulations of dye transport. It was found that the strong transverse variability of residual currents in the Admiralty Inlet results in a dominant seaward transport along the eastern shore and a dominant landward transport along the western shore of the Inlet. A similar transport pattern in Hood Canal is caused by the presence of tidal residual eddies near the entrance of the canal. Model results show that tidal residual currents in Whidbey Basin are small in comparison to other sub-basins. A large clockwise residual circulation is formed around Vashon Island near entrance of South Sound, which can potentially constrain the water exchange between the Central Basin and South Sound.

Yang, Zhaoqing; Wang, Taiping

2013-08-30T23:59:59.000Z

134

Materialized community ground models for large-scale earthquake simulation  

E-Print Network [OSTI]

Materialized community ground models for large-scale earthquake simulation Steven W. Schlosser to ground motion sim- ulations, in which ground model datasets are fully materi- alized into octress stored as a service techniques in which scientific computation and storage services become more tightly intertwined. 1

Shewchuk, Jonathan

135

Large Scale Simulation of Tor: Modelling a Global Passive Adversary  

E-Print Network [OSTI]

. Implementing global passive adversary attacks on currently deployed low latency anonymous networks designs have been developed which attempt to apply mixes to low latency traffic. The most widelyLarge Scale Simulation of Tor: Modelling a Global Passive Adversary Gavin O' Gorman and Stephen

Blott, Stephen

136

Solar Simulations for the Atacama Large Millimeter Observatory Network  

E-Print Network [OSTI]

The Atacama Large Millimeter/submillimeter Array (ALMA) will be a valuable tool for observing the chromosphere of our Sun at (sub-)millimeter wavelengths at high spatial, temporal and spectral resolution and as such has great potential to address long-standing scientific questions in solar physics. In order to make the best use of this scientific opportunity, the Solar Simulations for the Atacama Large Millimeter Observatory Network has been initiated. A key goal of this international collaboration is to support the preparation and interpretation of future observations of the Sun with ALMA.

Wedemeyer, Sven; Brajsa, Roman; Barta, Miroslav; Shimojo, Masumi

2015-01-01T23:59:59.000Z

137

The Fidelity of Ocean Models With Explicit Eddies (Chapter 17)  

SciTech Connect (OSTI)

Current practices within the oceanographic community have been reviewed with regard to the use of metrics to assess the realism of the upper-ocean circulation, ventilation processes diagnosed by time-evolving mixed layer depth and mode water formation, and eddy heat fluxes in large-scale fine resolution ocean model simulations. We have striven to understand the fidelity of these simulations in the context of their potential use in future fine-resolution coupled climate system studies. A variety of methodologies are used to assess the veracity of the numerical simulations. Sea surface height variability and the location of western boundary current paths from altimetry have been used routinely as basic indicators of fine-resolution model performance. Drifters and floats have also been used to provide pseudo-Eulerian measures of the mean and variability of surface and sub-surface flows, while statistical comparisons of observed and simulated means have been carried out using James tests. Probability density functions have been used to assess the Gaussian nature of the observed and simulated flows. Length and time scales have been calculated in both Eulerian and Lagrangian frameworks from altimetry and drifters, respectively. Concise measures of multiple model performance have been obtained from Taylor diagrams. The time-evolution of the mixed layer depth at monitoring stations has been compared with simulated time series. Finally, eddy heat fluxes are compared to climatological inferences.

McClean, J; Jayne, S; Maltrud, M; Ivanova, D

2007-08-01T23:59:59.000Z

138

Numerical simulation of flow distribution for pebble bed high temperature gas cooled reactors  

E-Print Network [OSTI]

?....................................................................................26 V CFD MODELLING ...................................................................................28 V.1 Computational Fluid Dynamics (CFD) ..........................................28 V.2 The History.... Hassan The premise of the work presented here is to use a common analytical tool, Computational Fluid Dynamics (CFD), along with different turbulence models. Eddy viscosity models as well as state-of-the-art Large Eddy Simulation (LES) were...

Yesilyurt, Gokhan

2004-09-30T23:59:59.000Z

139

Molecular Dynamics Simulations from SNL's Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS)  

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

LAMMPS (http://lammps.sandia.gov/index.html) stands for Large-scale Atomic/Molecular Massively Parallel Simulator and is a code that can be used to model atoms or, as the LAMMPS website says, as a parallel particle simulator at the atomic, meso, or continuum scale. This Sandia-based website provides a long list of animations from large simulations. These were created using different visualization packages to read LAMMPS output, and each one provides the name of the PI and a brief description of the work done or visualization package used. See also the static images produced from simulations at http://lammps.sandia.gov/pictures.html The foundation paper for LAMMPS is: S. Plimpton, Fast Parallel Algorithms for Short-Range Molecular Dynamics, J Comp Phys, 117, 1-19 (1995), but the website also lists other papers describing contributions to LAMMPS over the years.

Plimpton, Steve; Thompson, Aidan; Crozier, Paul

140

Interface Exchange as an Indicator for Eddy Heat Transport  

SciTech Connect (OSTI)

The ocean contains many large-scale, long-lived vortices, called mesoscale eddies, that are believed to have a role in the transport and redistribution of salt, heat, and nutrients throughout the ocean. Determining this role, however, has proven to be a challenge, since the mechanics of eddies are only partly understood; a standard definition for these ocean eddies does not exist and, therefore, scientifically meaningful, robust methods for eddy extraction, characterization, tracking and visualization remain a challenge. In order to shed light on the nature and potential roles of eddies, we have combined our previous research on eddy identification and tracking, and have used those approaches as the basis for analysis-driven computational experiments on the nature of eddies. Based on the resulting visualizations of eddy behavior, we have devised a new metric to characterize the transfer of water into and out of eddies across their boundary, and have developed visualization methods for this new metric to provide clues about the role eddies play in the global ocean and, potentially, climate change.

Petersen, Mark R. [Los Alamos National Laboratory; Williams, Sean J. [Los Alamos National Laboratory; Hecht, Matthew W. [Los Alamos National Laboratory; Maltrud, Mathew E. [Los Alamos National Laboratory; Hamann, Bernd [U of California Davis; Patchett, John M. [Los Alamos National Laboratory; Ahrens, James P. [Los Alamos National Laboratory

2012-06-12T23:59:59.000Z

Note: This page contains sample records for the topic "large eddy simulation" 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

Characterizing the Separation and Reattachment of Suction Surface Boundary Layer in Low Pressure Turbine Using Massively Parallel Large Eddy Simulations  

E-Print Network [OSTI]

cient, p p1 1 2 U21 Cax Axial chord H12 Form factor R11 Correlation coe cient Tu Turbulence intensity Ue Boundary layer edge velocity U1 Freestream velocity 1 Displacement thickness of a boundary layer 2 Momentum thickness of a boundary...

Jagannathan, Shriram

2012-02-14T23:59:59.000Z

142

A Large-Eddy Simulation Study of the Influence of Subsidence on the Stably Stratified Atmospheric Boundary Layer  

E-Print Network [OSTI]

snow/ice pack interior, which constrains surface cooling.snow/ice pack. They suggest that the strong cooling of theice pack. During clear-sky conditions, strong radiative cooling

Mirocha, Jeffrey D.; Kosovi?, Branko

2010-01-01T23:59:59.000Z

143

Final Report on the “New Directions in the Variational Multiscale Formulation of Large Eddy Simulation of Turbulence”  

SciTech Connect (OSTI)

In the report we present a summary of the new models and algorithms developed by the PI and the students supported by this grant. These developments are described in detail in ten peer-reviewed journal articles that acknowledge support from this grant.

Oberai, Assad A [Rensselaer Polytechnic Instistute

2013-07-16T23:59:59.000Z

144

A Large-Eddy Simulation Study of the Influence of Subsidence on the Stably Stratified Atmospheric Boundary Layer  

E-Print Network [OSTI]

temperature, wind speed, vertical heat and momentum ?uxes,ABL is vertical wind shear, with the wind speed at the

Mirocha, Jeffrey D.; Kosovi?, Branko

2010-01-01T23:59:59.000Z

145

A Large-Eddy Simulation Study of the Influence of Subsidence on the Stably Stratified Atmospheric Boundary Layer  

E-Print Network [OSTI]

Mean pro?les of potential temperature, wind speed, verticalsection. 4.1 Potential Temperature and Wind Speed Pro?lesequilibrium LES potential temperature and wind speed pro?les

Mirocha, Jeffrey D.; Kosovi?, Branko

2010-01-01T23:59:59.000Z

146

Fast time domain simulation for large order hybrid systems  

E-Print Network [OSTI]

Simulation is an important tool for the analysis and design of complex systems. As the models become more and more complex, more powerful simulation methods are desired. As an attempt to address this problem, a simulation ...

Sou, Kin Cheong, 1979-

2002-01-01T23:59:59.000Z

147

Large-Scale Atomistic Simulations of Material Failure  

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

These simulations from 2000 examine the supersonic propagation of cracks and the formation of complex junction structures in metals. Eight simulations concerning brittle fracture, ductile failure, and shockless compression are available.

Abraham, Farid [IBM Almaden Research; Duchaineau, Mark [LLNL; Wirth, Brian [LLNL; Heidelberg,; Seager, Mark [LLNL; De La Rubia, Diaz [LLNL

148

Nuclear EMP simulation for large-scale urban environments. FDTD for electrically large problems.  

SciTech Connect (OSTI)

In case of a terrorist nuclear attack in a metropolitan area, EMP measurement could provide: (1) a prompt confirmation of the nature of the explosion (chemical or nuclear) for emergency response; and (2) and characterization parameters of the device (reaction history, yield) for technical forensics. However, urban environment could affect the fidelity of the prompt EMP measurement (as well as all other types of prompt measurement): (1) Nuclear EMP wavefront would no longer be coherent, due to incoherent production, attenuation, and propagation of gamma and electrons; and (2) EMP propagation from source region outward would undergo complicated transmission, reflection, and diffraction processes. EMP simulation for electrically-large urban environment: (1) Coupled MCNP/FDTD (Finite-difference time domain Maxwell solver) approach; and (2) FDTD tends to be limited to problems that are not 'too' large compared to the wavelengths of interest because of numerical dispersion and anisotropy. We use a higher-order low-dispersion, isotropic FDTD algorithm for EMP propagation.

Smith, William S. [Los Alamos National Laboratory; Bull, Jeffrey S. [Los Alamos National Laboratory; Wilcox, Trevor [Los Alamos National Laboratory; Bos, Randall J. [Los Alamos National Laboratory; Shao, Xuan-Min [Los Alamos National Laboratory; Goorley, John T. [Los Alamos National Laboratory; Costigan, Keeley R. [Los Alamos National Laboratory

2012-08-13T23:59:59.000Z

149

Architectural Design and Complexity Analysis of Large-Scale Cortical Simulation on a Hybrid Computing Platform  

E-Print Network [OSTI]

- performance computing platform for large-scale mathematical models. Traditional computing architecture cannot hybrid computing architecture for the simulation and evaluation of large-scale associative neural memory models. The proposed architecture achieves very high computing and communication performances

Qiu, Qinru

150

Large-Scale Molecular Dynamics Simulations for Highly Parallel Infrastructures  

E-Print Network [OSTI]

Computational chemistry allows researchers to experiment in sillico: by running a computer simulations of a biological or chemical processes of interest. Molecular dynamics with molecular mechanics model of interactions simulates N-body problem of atoms$-$it computes movements of atoms according to Newtonian physics and empirical descriptions of atomic electrostatic interactions. These simulations require high performance computing resources, as evaluations within each step are computationally demanding and billions of steps are needed to reach interesting timescales. Current methods decompose the spatial domain of the problem and calculate on parallel/distributed infrastructures. Even the methods with the highest strong scaling hit the limit at half a million cores: they are not able to cut the time to result if provided with more processors. At the dawn of exascale computing with massively parallel computational resources, we want to increase the level of parallelism by incorporating parallel-in-time comput...

Pazúriková, Jana

2014-01-01T23:59:59.000Z

151

Real-time Monitoring of Large Scientific Simulations  

E-Print Network [OSTI]

space-filling curves. The Lebesgue curve is also known as Z-order, Morton, .... Curve. Special case. · Simple load balancing on visualization side. · Fast slicing, isosurfacing, and volume rendering. #12;The7 B8 B13 B14 B15 B16 · Takes advantage of simulation load balancing · One Data Source per compute

Pascucci, Valerio

152

Large-scale simulator for global data infrastructure optimization  

E-Print Network [OSTI]

Companies depend on information systems to control their operations. During the last decade, Information Technology (IT) infrastructures have grown in scale and complexity. Any large company runs many enterprise applications ...

Herrero-López, Sergio

2012-01-01T23:59:59.000Z

153

The use of large plot rainfall simulation to investigate  

E-Print Network [OSTI]

by macropore flow. On the intercanopy site, 12.67% of the water left the site as surface runoff and ?3% left as shallow subsurface flow. Large root channels and conduits, which were not present on the intercanopy site, within the soil may promote shallow...

Sorenson, Joshua Russell

2006-04-12T23:59:59.000Z

154

Seasonal Modulation of Eddy Kinetic Energy and Its Formation Mechanism in the Southeast Indian Ocean  

E-Print Network [OSTI]

energy and exert profound impacts on large-scale ocean circulations. Satellite altimeter ob- servations- sociations with the large-scale oceanic circulations and the climate. The global eddy kinetic energy (EKESeasonal Modulation of Eddy Kinetic Energy and Its Formation Mechanism in the Southeast Indian

Qiu, Bo

155

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

156

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

157

Modeling of Diesel Combustion, Soot and NO Emissions Based on a Modified Eddy Dissipation Concept  

E-Print Network [OSTI]

1 Modeling of Diesel Combustion, Soot and NO Emissions Based on a Modified Eddy Dissipation Concept and soot emissions modeling, computational diesel engine simulations, eddy dissipation concept #12 ignition, combustion, NOx and soot emissions over a wide range of operating conditions in a diesel engine

Im, Hong G.

158

An avenue of eddies: Quantifying the biophysical properties of mesoscale eddies in the Tasman Sea  

E-Print Network [OSTI]

after separating from the coast. Through a 16-year analysis of Tasman Sea eddies, we identify a region of cyclonic and anticyclonic eddies within Eddy Avenue is 23% and 16% higher respectively than the broader Tasman Sea. We find that Eddy Avenue cyclonic and anti- cyclonic eddies have more strongly differentiated

Oke, Peter

159

LES/probability density function approach for the simulation of an ethanol spray flame  

E-Print Network [OSTI]

LES/probability density function approach for the simulation of an ethanol spray flame Colin Heye a an experimental pilot-stabilized ethanol spray flame. In this particular flame, droplet evaporation occurs away: Large-eddy simulation; Probability density function; Flamelet/progress variable approach; Ethanol

Raman, Venkat

160

Eddie Smith Dean E. Smith  

E-Print Network [OSTI]

Excellence Center for Loudermilk Graham Memorial Daniels Hill Ackland McCaskill Paul Green Eddie Smith Alumni Center Carmichael Arena Center Student Dean E. Smith Student Hall Kenan Field HouseStadium Kenan Hill

Doyle, Martin

Note: This page contains sample records for the topic "large eddy simulation" 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

Eddie Smith Dean E. Smith  

E-Print Network [OSTI]

Daniels Hill Ackland McCaskill Paul Green Eddie Smith Alumni Center Carmichael Auditorium Center Student Dean E. Smith Student Hall Kenan Field House Bookstore Affairs Stadium Kenan Hill Williams House Forest

Whitton, Mary C.

162

Generation of strong mesoscale eddies by weak ocean gyres by Michael A. Spall1  

E-Print Network [OSTI]

Generation of strong mesoscale eddies by weak ocean gyres by Michael A. Spall1 ABSTRACT The generation of strong mesoscale variability through instability of the large-scale circulation in the interior of oceanic gyres is addressed. While previous studies have shown that eddies generated from weakly sheared

163

Large scale test simulations using the Virtual Environment for Test Optimization (VETO)  

SciTech Connect (OSTI)

The Virtual Environment for Test Optimization (VETO) is a set of simulation tools under development at Sandia to enable test engineers to do computer simulations of tests. The tool set utilizes analysis codes and test information to optimize design parameters and to provide an accurate model of the test environment which aides in the maximization of test performance, training, and safety. Previous VETO effort has included the development of two structural dynamics simulation modules that provide design and optimization tools for modal and vibration testing. These modules have allowed test engineers to model and simulate complex laboratory testing, to evaluate dynamic response behavior, and to investigate system testability. Further development of the VETO tool set will address the accurate modeling of large scale field test environments at Sandia. These field test environments provide weapon system certification capabilities and have different simulation requirements than those of laboratory testing.

Klenke, S.E.; Heffelfinger, S.R.; Bell, H.J.; Shierling, C.L.

1997-10-01T23:59:59.000Z

164

Eddy diffusivities of inertial particles under gravity  

E-Print Network [OSTI]

The large-scale/long-time transport of inertial particles of arbitrary mass density under gravity is investigated by means of a formal multiple-scale perturbative expansion in the scale-separation parametre between the carrier flow and the particle concentration field. The resulting large-scale equation for the particle concentration is determined, and is found to be diffusive with a positive-definite eddy diffusivity. The calculation of the latter tensor is reduced to the resolution of an auxiliary differential problem, consisting of a coupled set of two differential equations in a (6+1)-dimensional coordinate system (3 space coordinates plus 3 velocity coordinates plus time). Although expensive, numerical methods can be exploited to obtain the eddy diffusivity, for any desirable non-perturbative limit (e.g. arbitrary Stokes and Froude numbers). The aforementioned large-scale equation is then specialized to deal with two different relevant perturbative limits: i) vanishing of both Stokes time and sedimenting particle velocity; ii) vanishing Stokes time and finite sedimenting particle velocity. Both asymptotics lead to a greatly simplified auxiliary differential problem, now involving only space coordinates and thus easy to be tackled by standard numerical techniques. Explicit, exact expressions for the eddy diffusivities have been calculated, for both asymptotics, for the class of parallel flows, both static and time-dependent. This allows us to investigate analytically the role of gravity and inertia on the diffusion process by varying relevant features of the carrier flow, as e.g. the form of its temporal correlation function. Our results exclude a universal role played by gravity and inertia on the diffusive behaviour: regimes of both enhanced and reduced diffusion may exist, depending on the detailed structure of the carrier flow.

Marco Martins Afonso; Andrea Mazzino; Paolo Muratore-Ginanneschi

2011-03-29T23:59:59.000Z

165

CONSTRUCTION AND CALIBRATION OF A LARGE-SCALE MICRO-SIMULATION MODEL OF THE SALT LAKE AREA  

E-Print Network [OSTI]

CONSTRUCTION AND CALIBRATION OF A LARGE-SCALE MICRO-SIMULATION MODEL OF THE SALT LAKE AREA H. Rakha-scale network using a microscopic simulation model. The requirements of a validated microscopic model for large of Intelligent Transportation System (ITS) applications. Typically, microscopic simulation models have been

Rakha, Hesham A.

166

Large-Scale Fluid-Structure Interaction Simulation of Viscoplastic and Fracturing  

E-Print Network [OSTI]

of large plastic deformations and rupture of thin alu- minum tubes due to the passage of ethylene-oxygen detonations. 1 Introduction The Center for Simulation of Dynamic Response of Materials at the California In with such a "weakly coupled" method, when the evolving interface geometry and velocities are imposed as boundary

Deiterding, Ralf

167

Simulation of large-amplitude motion of floating wind turbines using conservation of momentum  

E-Print Network [OSTI]

of a floating wind turbine support structure capable of maintaining a near-vertical tower requires buoyancy far. The compliant floating wind turbine system can be considered as a multi-body system including tower, rotorSimulation of large-amplitude motion of floating wind turbines using conservation of momentum Lei

Sweetman, Bert

168

Dynamic procedure for filtered gyrokinetic simulations  

SciTech Connect (OSTI)

Large eddy simulations (LES) of gyrokinetic plasma turbulence are investigated as interesting candidates to decrease the computational cost. A dynamic procedure is implemented in the gene code, allowing for dynamic optimization of the free parameters of the LES models (setting the amplitudes of dissipative terms). Employing such LES methods, one recovers the free energy and heat flux spectra obtained from highly resolved direct numerical simulations. Systematic comparisons are performed for different values of the temperature gradient and magnetic shear, parameters which are of prime importance in ion temperature gradient driven turbulence. Moreover, the degree of anisotropy of the problem, which can vary with parameters, can be adapted dynamically by the method that shows gyrokinetic large eddy simulation to be a serious candidate to reduce numerical cost of gyrokinetic solvers.

Morel, P.; Banon Navarro, A.; Albrecht-Marc, M.; Carati, D. [Statistical and Plasma Physics Laboratory, Universite Libre de Bruxelles, Bruxelles 1050 (Belgium); Merz, F.; Goerler, T.; Jenko, F. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)

2012-01-15T23:59:59.000Z

169

NV Energy Large-Scale Photovoltaic Integration Study: Intra-Hour Dispatch and AGC Simulation  

SciTech Connect (OSTI)

The uncertainty and variability with photovoltaic (PV) generation make it very challenging to balance power system generation and load, especially under high penetration cases. Higher reserve requirements and more cycling of conventional generators are generally anticipated for large-scale PV integration. However, whether the existing generation fleet is flexible enough to handle the variations and how well the system can maintain its control performance are difficult to predict. The goal of this project is to develop a software program that can perform intra-hour dispatch and automatic generation control (AGC) simulation, by which the balancing operations of a system can be simulated to answer the questions posed above. The simulator, named Electric System Intra-Hour Operation Simulator (ESIOS), uses the NV Energy southern system as a study case, and models the system’s generator configurations, AGC functions, and operator actions to balance system generation and load. Actual dispatch of AGC generators and control performance under various PV penetration levels can be predicted by running ESIOS. With data about the load, generation, and generator characteristics, ESIOS can perform similar simulations and assess variable generation integration impacts for other systems as well. This report describes the design of the simulator and presents the study results showing the PV impacts on NV Energy real-time operations.

Lu, Shuai; Etingov, Pavel V.; Meng, Da; Guo, Xinxin; Jin, Chunlian; Samaan, Nader A.

2013-01-02T23:59:59.000Z

170

SSALMON - The Solar Simulations for the Atacama Large Millimeter Observatory Network  

E-Print Network [OSTI]

The Solar Simulations for the Atacama Large Millimeter Observatory Network (SSALMON) was initiated in 2014 in connection with two ALMA development studies. The Atacama Large Millimeter/submillimeter Array (ALMA) is a powerful new tool, which can also observe the Sun at high spatial, temporal, and spectral resolution. The international SSALMONetwork aims at coordinating the further development of solar observing modes for ALMA and at promoting scientific opportunities for solar physics with particular focus on numerical simulations, which can provide important constraints for the observing modes and can aid the interpretation of future observations. The radiation detected by ALMA originates mostly in the solar chromosphere - a complex and dynamic layer between the photosphere and corona, which plays an important role in the transport of energy and matter and the heating of the outer layers of the solar atmosphere. Potential targets include active regions, prominences, quiet Sun regions, flares. Here, we give a...

Wedemeyera, S; Brajsa, R; Barta, M; Hudson, H; Fleishman, G; Loukitcheva, M; Fleck, B; Kontar, E; De Pontieu, B; Tiwari, S; Kato, Y; Soler, R; Yagoubov, P; Black, J H; Antolin, P; Gunar, S; Labrosse, N; Benz, A O; Nindos, A; Steffen, M; Scullion, E; Doyle, J G; Zaqarashvili, T; Hanslmeier, A; Nakariakov, V M; Heinzel, P; Ayres, T; Karlicky, M

2015-01-01T23:59:59.000Z

171

Large-eddy simulations of structure effects of an upstream elbow main pipe on hot and cold fluids mixing in a vertical tee junction  

E-Print Network [OSTI]

power plant. Thermal fatigue is an important degradation mechanism for the life time assessment in e.g. nuclear power plants. In the present work, the mixing of a hot and a cold fluid stream place both in nuclear plants involving light water and sodium cooled reactors due to thermal fatigue

Attinger, Daniel

172

Effects of Data Resolution and Human Behavior on Large Scale Evacuation Simulations  

E-Print Network [OSTI]

Traffic Analysis Zones (TAZ) based macroscopic simulation studies are mostly applied in evacuation planning and operation areas. The large size in TAZ and aggregated information of macroscopic simulation underestimate the real evacuation performance. To take advantage of the high resolution demographic data LandScan USA (the zone size is much smaller than TAZ) and agent-based microscopic traffic simulation models, many new problems appeared and novel solutions are needed. A series of studies are conducted using LandScan USA Population Cells (LPC) data for evacuation assignments with different network configurations, travel demand models, and travelers compliance behavior. First, a new Multiple Source Nearest Destination Shortest Path (MSNDSP) problem is defined for generating Origin Destination matrix in evacuation assignments when using LandScan dataset. Second, a new agent-based traffic assignment framework using LandScan and TRANSIMS modules is proposed for evacuation planning and operation study. Impact a...

Lu, Wei

2015-01-01T23:59:59.000Z

173

Mesh-free simulations of shear banding in large deformation Shaofan Li, Wei Hao, Wing Kam Liu *  

E-Print Network [OSTI]

Mesh-free simulations of shear banding in large deformation Shaofan Li, Wei Hao, Wing Kam Liu Mesh-free approximation is used in numerical simulations of strain localization under large deformation. An explicit displacement based mesh-free formulation is used in both two-dimensional and three

Li, Shaofan

174

Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider  

E-Print Network [OSTI]

The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010--2013, the LHC was routinely storing protons at 3.5--4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An un-controlled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multi-stage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the collimation system. The studies include tracking of protons through the fields of more than 5000 magnets in the 27 km LHC ring over hundreds of revolutions, and Monte-Carlo simulations of particle-matter interactions both in collimators and machine elements being hit by escaping particles. The simulation results agree typically within a factor 2 with measurements of beam loss distributions from the previous LHC run. Considering the complex simulation, which must account for a very large number of unknown imperfections, and in view of the total losses around the ring spanning over 7 orders of magnitude, we consider this an excellent agreement. Our results give confidence in the simulation tools, which are used also for the design of future accelerators.

R. Bruce; R. W. Assmann; V. Boccone; C. Bracco; M. Brugger; M. Cauchi; F. Cerutti; D. Deboy; A. Ferrari; L. Lari; A. Marsili; A. Mereghetti; D. Mirarchi; E. Quaranta; S. Redaelli; G. Robert-Demolaize; A. Rossi; B. Salvachua; E. Skordis; C. Tambasco; G. Valentino; T. Weiler; V. Vlachoudis; D. Wollmann

2014-09-10T23:59:59.000Z

175

ClimateSimulation Biogeochemistry  

E-Print Network [OSTI]

to sequester further CO2 emissions. Chlorophyll concentration from an eddy-resolving POP simulation with full ability of the ocean to sequester further CO2 emissions. Chlorophyll concentration from an eddy release and the future ability of the ocean to sequester further CO2 emissions. Chlorophyll concentration

176

Testing of Large-Scale ICV Glasses with Hanford LAW Simulant  

SciTech Connect (OSTI)

Preliminary glass compositions for immobilizing Hanford low-activity waste (LAW) by the in-container vitrification (ICV) process were initially fabricated at crucible- and engineering-scale, including simulants and actual (radioactive) LAW. Glasses were characterized for vapor hydration test (VHT) and product consistency test (PCT) responses and crystallinity (both quenched and slow-cooled samples). Selected glasses were tested for toxicity characteristic leach procedure (TCLP) responses, viscosity, and electrical conductivity. This testing showed that glasses with LAW loading of 20 mass% can be made readily and meet all product constraints by a far margin. Glasses with over 22 mass% Na2O can be made to meet all other product quality and process constraints. Large-scale testing was performed at the AMEC, Geomelt Division facility in Richland. Three tests were conducted using simulated LAW with increasing loadings of 12, 17, and 20 mass% Na2O. Glass samples were taken from the test products in a manner to represent the full expected range of product performance. These samples were characterized for composition, density, crystalline and non-crystalline phase assemblage, and durability using the VHT, PCT, and TCLP tests. The results, presented in this report, show that the AMEC ICV product with meets all waste form requirements with a large margin. These results provide strong evidence that the Hanford LAW can be successfully vitrified by the ICV technology and can meet all the constraints related to product quality. The economic feasibility of the ICV technology can be further enhanced by subsequent optimization.

Hrma, Pavel R.; Kim, Dong-Sang; Vienna, John D.; Matyas, Josef; Smith, Donald E.; Schweiger, Michael J.; Yeager, John D.

2005-03-01T23:59:59.000Z

177

A combination of streamtube and geostatical simulation methodologies for the study of large oil reservoirs  

SciTech Connect (OSTI)

The application of streamtube models for reservoir simulation has an extensive history in the oil industry. Although these models are strictly applicable only to fields under voidage balance, they have proved to be useful in a large number of fields provided that there is no solution gas evolution and production. These models combine the benefit of very fast computational time with the practical ability to model a large reservoir over the course of its history. These models do not, however, directly incorporate the detailed geological information that recent experience has taught is important. This paper presents a technique for mapping the saturation information contained in a history matched streamtube model onto a detailed geostatistically derived finite difference grid. With this technique, the saturation information in a streamtube model, data that is actually statistical in nature, can be identified with actual physical locations in a field and a picture of the remaining oil saturation can be determined. Alternatively, the streamtube model can be used to simulate the early development history of a field and the saturation data then used to initialize detailed late time finite difference models. The proposed method is presented through an example application to the Ninian reservoir. This reservoir, located in the North Sea (UK), is a heterogeneous sandstone characterized by a line drive waterflood, with about 160 wells, and a 16 year history. The reservoir was satisfactorily history matched and mapped for remaining oil saturation. A comparison to 3-D seismic survey and recently drilled wells have provided preliminary verification.

Chakravarty, A.; Emanuel, A.S.; Bernath, J.A. [Chevron Petroleum Technology Company, LaHabra, CA (United States)

1997-08-01T23:59:59.000Z

178

A Metascalable Computing Framework for Large Spatiotemporal-Scale Atomistic Simulations  

SciTech Connect (OSTI)

A metascalable (or 'design once, scale on new architectures') parallel computing framework has been developed for large spatiotemporal-scale atomistic simulations of materials based on spatiotemporal data locality principles, which is expected to scale on emerging multipetaflops architectures. The framework consists of: (1) an embedded divide-and-conquer (EDC) algorithmic framework based on spatial locality to design linear-scaling algorithms for high complexity problems; (2) a space-time-ensemble parallel (STEP) approach based on temporal locality to predict long-time dynamics, while introducing multiple parallelization axes; and (3) a tunable hierarchical cellular decomposition (HCD) parallelization framework to map these O(N) algorithms onto a multicore cluster based on hybrid implementation combining message passing and critical section-free multithreading. The EDC-STEP-HCD framework exposes maximal concurrency and data locality, thereby achieving: (1) inter-node parallel efficiency well over 0.95 for 218 billion-atom molecular-dynamics and 1.68 trillion electronic-degrees-of-freedom quantum-mechanical simulations on 212,992 IBM BlueGene/L processors (superscalability); (2) high intra-node, multithreading parallel efficiency (nanoscalability); and (3) nearly perfect time/ensemble parallel efficiency (eon-scalability). The spatiotemporal scale covered by MD simulation on a sustained petaflops computer per day (i.e. petaflops {center_dot} day of computing) is estimated as NT = 2.14 (e.g. N = 2.14 million atoms for T = 1 microseconds).

Nomura, K; Seymour, R; Wang, W; Kalia, R; Nakano, A; Vashishta, P; Shimojo, F; Yang, L H

2009-02-17T23:59:59.000Z

179

Eddy mean flow decomposition and eddy diffusivity estimates in the tropical Pacific Ocean  

E-Print Network [OSTI]

Eddy mean flow decomposition and eddy diffusivity estimates in the tropical Pacific Ocean: 2] Eddy diffusivity of the surface velocity field in the tropical Pacific Ocean was estimated using diffusivity estimates in the tropical Pacific Ocean: 2. Results, J. Geophys. Res., 107(C10), 3154, doi:10

180

Eddy formation and propagation in the eastern tropical Pacific  

E-Print Network [OSTI]

Observations of eddies in the eastern tropical Pacific from TOPEX altimetry data show that there are seasonal and interannual variations in eddy activity. Comparisons between time of eddy formation and corresponding wind data show that not all...

Jhingran, Vikas Gopal

1997-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "large eddy simulation" 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

Properties of liquid clusters in large-scale molecular dynamics nucleation simulations  

SciTech Connect (OSTI)

We have performed large-scale Lennard-Jones molecular dynamics simulations of homogeneous vapor-to-liquid nucleation, with 10{sup 9} atoms. This large number allows us to resolve extremely low nucleation rates, and also provides excellent statistics for cluster properties over a wide range of cluster sizes. The nucleation rates, cluster growth rates, and size distributions are presented in Diemand et al. [J. Chem. Phys. 139, 74309 (2013)], while this paper analyses the properties of the clusters. We explore the cluster temperatures, density profiles, potential energies, and shapes. A thorough understanding of the properties of the clusters is crucial to the formulation of nucleation models. Significant latent heat is retained by stable clusters, by as much as ?kT = 0.1? for clusters with size i = 100. We find that the clusters deviate remarkably from spherical—with ellipsoidal axis ratios for critical cluster sizes typically within b/c = 0.7 ± 0.05 and a/c = 0.5 ± 0.05. We examine cluster spin angular momentum, and find that it plays a negligible role in the cluster dynamics. The interfaces of large, stable clusters are thinner than planar equilibrium interfaces by 10%?30%. At the critical cluster size, the cluster central densities are between 5% and 30% lower than the bulk liquid expectations. These lower densities imply larger-than-expected surface areas, which increase the energy cost to form a surface, which lowers nucleation rates.

Angélil, Raymond; Diemand, Jürg [Institute for Theoretical Physics, University of Zurich, 8057 Zurich (Switzerland)] [Institute for Theoretical Physics, University of Zurich, 8057 Zurich (Switzerland); Tanaka, Kyoko K.; Tanaka, Hidekazu [Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819 (Japan)] [Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819 (Japan)

2014-02-21T23:59:59.000Z

182

Targeting Atmospheric Simulation Algorithms for Large Distributed Memory GPU Accelerated Computers  

SciTech Connect (OSTI)

Computing platforms are increasingly moving to accelerated architectures, and here we deal particularly with GPUs. In [15], a method was developed for atmospheric simulation to improve efficiency on large distributed memory machines by reducing communication demand and increasing the time step. Here, we improve upon this method to further target GPU accelerated platforms by reducing GPU memory accesses, removing a synchronization point, and better clustering computations. The modification ran over two times faster in some cases even though more computations were required, demonstrating the merit of improving memory handling on the GPU. Furthermore, we discover that the modification also has a near 100% hit rate in fast on-chip L1 cache and discuss the reasons for this. In concluding, we remark on further potential improvements to GPU efficiency.

Norman, Matthew R [ORNL

2013-01-01T23:59:59.000Z

183

New Eddy Correlation Systems Installed  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the Contributions andDataNational Library of1,Department ofNew Eddy Correlation System3

184

Eddy Correlation Systems Receive Upgrade  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed NewcatalystNeutronEnvironmentZIRKLE FRUITYear 1 WinnersEd Bailey Ed Bailey2 Eddy

185

Mathematics and Computers in Simulation 65 (2004) 557577 Parallel runs of a large air pollution model on a  

E-Print Network [OSTI]

-three decades. The need to establish reliable control strategies for the air pollution levels will become evenMathematics and Computers in Simulation 65 (2004) 557­577 Parallel runs of a large air pollution 20 January 2004; accepted 21 January 2004 Abstract Large-scale air pollution models can successfully

186

Large-scale Nanostructure Simulations from X-ray Scattering Data On Graphics Processor Clusters  

SciTech Connect (OSTI)

X-ray scattering is a valuable tool for measuring the structural properties of materialsused in the design and fabrication of energy-relevant nanodevices (e.g., photovoltaic, energy storage, battery, fuel, and carbon capture andsequestration devices) that are key to the reduction of carbon emissions. Although today's ultra-fast X-ray scattering detectors can provide tremendousinformation on the structural properties of materials, a primary challenge remains in the analyses of the resulting data. We are developing novelhigh-performance computing algorithms, codes, and software tools for the analyses of X-ray scattering data. In this paper we describe two such HPCalgorithm advances. Firstly, we have implemented a flexible and highly efficient Grazing Incidence Small Angle Scattering (GISAXS) simulation code based on theDistorted Wave Born Approximation (DWBA) theory with C++/CUDA/MPI on a cluster of GPUs. Our code can compute the scattered light intensity from any givensample in all directions of space; thus allowing full construction of the GISAXS pattern. Preliminary tests on a single GPU show speedups over 125x compared tothe sequential code, and almost linear speedup when executing across a GPU cluster with 42 nodes, resulting in an additional 40x speedup compared to usingone GPU node. Secondly, for the structural fitting problems in inverse modeling, we have implemented a Reverse Monte Carlo simulation algorithm with C++/CUDAusing one GPU. Since there are large numbers of parameters for fitting in the in X-ray scattering simulation model, the earlier single CPU code required weeks ofruntime. Deploying the AccelerEyes Jacket/Matlab wrapper to use GPU gave around 100x speedup over the pure CPU code. Our further C++/CUDA optimization deliveredan additional 9x speedup.

Sarje, Abhinav; Pien, Jack; Li, Xiaoye; Chan, Elaine; Chourou, Slim; Hexemer, Alexander; Scholz, Arthur; Kramer, Edward

2012-01-15T23:59:59.000Z

187

Thermal Performance Evaluation of Attic Radiant Barrier Systems Using the Large Scale Climate Simulator (LSCS)  

SciTech Connect (OSTI)

Application of radiant barriers and low-emittance surface coatings in residential building attics can significantly reduce conditioning loads from heat flow through attic floors. The roofing industry has been developing and using various radiant barrier systems and low-emittance surface coatings to increase energy efficiency in buildings; however, minimal data are available that quantifies the effectiveness of these technologies. This study evaluates performance of various attic radiant barrier systems under simulated summer daytime conditions and nighttime or low solar gain daytime winter conditions using the large scale climate simulator (LSCS). The four attic configurations that were evaluated are 1) no radiant barrier (control), 2) perforated low-e foil laminated oriented strand board (OSB) deck, 3) low-e foil stapled on rafters, and 4) liquid applied low-emittance coating on roof deck and rafters. All test attics used nominal RUS 13 h-ft2- F/Btu (RSI 2.29 m2-K/W) fiberglass batt insulation on attic floor. Results indicate that the three systems with radiant barriers had heat flows through the attic floor during summer daytime condition that were 33%, 50%, and 19% lower than the control, respectively.

Shrestha, Som S [ORNL] [ORNL; Miller, William A [ORNL] [ORNL; Desjarlais, Andre Omer [ORNL] [ORNL

2013-01-01T23:59:59.000Z

188

A scalable messaging system for accelerating discovery from large scale scientific simulations  

SciTech Connect (OSTI)

Emerging scientific and engineering simulations running at scale on leadership-class High End Computing (HEC) environments are producing large volumes of data, which has to be transported and analyzed before any insights can result from these simulations. The complexity and cost (in terms of time and energy) associated with managing and analyzing this data have become significant challenges, and are limiting the impact of these simulations. Recently, data-staging approaches along with in-situ and in-transit analytics have been proposed to address these challenges by offloading I/O and/or moving data processing closer to the data. However, scientists continue to be overwhelmed by the large data volumes and data rates. In this paper we address this latter challenge. Specifically, we propose a highly scalable and low-overhead associative messaging framework that runs on the data staging resources within the HEC platform, and builds on the staging-based online in-situ/in- transit analytics to provide publish/subscribe/notification-type messaging patterns to the scientist. Rather than having to ingest and inspect the data volumes, this messaging system allows scientists to (1) dynamically subscribe to data events of interest, e.g., simple data values or a complex function or simple reduction (max()/min()/avg()) of the data values in a certain region of the application domain is greater/less than a threshold value, or certain spatial/temporal data features or data patterns are detected; (2) define customized in-situ/in-transit actions that are triggered based on the events, such as data visualization or transformation; and (3) get notified when these events occur. The key contribution of this paper is a design and implementation that can support such a messaging abstraction at scale on high- end computing (HEC) systems with minimal overheads. We have implemented and deployed the messaging system on the Jaguar Cray XK6 machines at Oak Ridge National Laboratory and the Lonestar system at the Texas Advanced Computing Center (TACC), and we present the experimental performance evaluation using these HEC platforms in the paper.

Jin, Tong [Rutgers University; Zhang, Fan [Rutgers University; Parashar, Manish [Rutgers University; Klasky, Scott A [ORNL; Podhorszki, Norbert [ORNL; Abbasi, Hasan [ORNL

2012-01-01T23:59:59.000Z

189

Large  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and Interfaces Sample6, 2011 CERN 73-11Large area avalanche photodiode

190

Rotating concave eddy current probe  

SciTech Connect (OSTI)

A rotating concave eddy current probe for detecting fatigue cracks hidden from view underneath the head of a raised head fastener, such as a buttonhead-type rivet, used to join together structural skins, such as aluminum aircraft skins. The probe has a recessed concave dimple in its bottom surface that closely conforms to the shape of the raised head. The concave dimple holds the probe in good alignment on top of the rivet while the probe is rotated around the rivet's centerline. One or more magnetic coils are rigidly embedded within the probe's cylindrical body, which is made of a non-conducting material. This design overcomes the inspection impediment associated with widely varying conductivity in fastened joints.

Roach, Dennis P. (Albuquerque, NM); Walkington, Phil (Albuquerque, NM); Rackow, Kirk A. (Albuquerque, NM); Hohman, Ed (Albuquerque, NM)

2008-04-01T23:59:59.000Z

191

Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider  

E-Print Network [OSTI]

The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010--2013, the LHC was routinely storing protons at 3.5--4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An un-controlled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multi-stage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the co...

Bruce, R; Boccone, V; Bracco, C; Brugger, M; Cauchi, M; Cerutti, F; Deboy, D; Ferrari, A; Lari, L; Marsili, A; Mereghetti, A; Mirarchi, D; Quaranta, E; Redaelli, S; Robert-Demolaize, G; Rossi, A; Salvachua, B; Skordis, E; Tambasco, C; Valentino, G; Weiler, T; Vlachoudis, V; Wollmann, D

2014-01-01T23:59:59.000Z

192

Eddy current technique for predicting burst pressure  

DOE Patents [OSTI]

A signal processing technique which correlates eddy current inspection data from a tube having a critical tubing defect with a range of predicted burst pressures for the tube is provided. The method can directly correlate the raw eddy current inspection data representing the critical tubing defect with the range of burst pressures using a regression technique, preferably an artificial neural network. Alternatively, the technique deconvolves the raw eddy current inspection data into a set of undistorted signals, each of which represents a separate defect of the tube. The undistorted defect signal which represents the critical tubing defect is related to a range of burst pressures utilizing a regression technique.

Petri, Mark C. (Yorkville, IL); Kupperman, David S. (Oak Park, IL); Morman, James A. (Woodridge, IL); Reifman, Jaques (Western Springs, IL); Wei, Thomas Y. C. (Downers Grove, IL)

2003-01-01T23:59:59.000Z

193

A new database generation method combining maximin method and kriging prediction for eddy-current testing  

E-Print Network [OSTI]

A new database generation method combining maximin method and kriging prediction for eddy in the domain of ECT ­ of using databases appeared recently. The database consists of well-chosen pairs of input the database instead of recoursing to the complicated and expensive-to-run simulation methods. How- ever

Paris-Sud XI, Université de

194

Reduced-Order Models of Zero-Net Mass-Flux Jets for Large-Scale Flow Control Simulations  

E-Print Network [OSTI]

Reduced-Order Models of Zero-Net Mass-Flux Jets for Large-Scale Flow Control Simulations Reni Raju computational tools are well suited for modeling the dynamics of zero-net mass-flux actuators, the computational vorticity, (s-1 ) I. Introduction ERO-net mass-flux (ZNMF) actuators or "synthetic jets" have potential

Mittal, Rajat

195

Negative magnetic eddy diffusivities from test-field method and multiscale stability theory  

E-Print Network [OSTI]

The generation of large-scale magnetic field in the kinematic regime in the absence of an alpha-effect is investigated by following two different approaches, namely the test-field method and multiscale stability theory relying on the homogenisation technique. We show analytically that the former, applied for the evaluation of magnetic eddy diffusivities, yields results that fully agree with the latter. Our computations of the magnetic eddy diffusivity tensor for the specific instances of the parity-invariant flow-IV of G.O. Roberts and the modified Taylor-Green flow in a suitable range of parameter values confirm the findings of previous studies, and also explain some of their apparent contradictions. The two flows have large symmetry groups; this is used to considerably simplify the eddy diffusivity tensor. Finally, a new analytic result is presented: upon expressing the eddy diffusivity tensor in terms of solutions to auxiliary problems for the adjoint operator, we derive relations between magnetic eddy dif...

Andrievsky, Alexander; Noullez, Alain; Zheligovsky, Vladislav

2015-01-01T23:59:59.000Z

196

Negative magnetic eddy diffusivities from test-field method and multiscale stability theory  

E-Print Network [OSTI]

The generation of large-scale magnetic field in the kinematic regime in the absence of an alpha-effect is investigated by following two different approaches, namely the test-field method and multiscale stability theory relying on the homogenisation technique. We show analytically that the former, applied for the evaluation of magnetic eddy diffusivities, yields results that fully agree with the latter. Our computations of the magnetic eddy diffusivity tensor for the specific instances of the parity-invariant flow-IV of G.O. Roberts and the modified Taylor-Green flow in a suitable range of parameter values confirm the findings of previous studies, and also explain some of their apparent contradictions. The two flows have large symmetry groups; this is used to considerably simplify the eddy diffusivity tensor. Finally, a new analytic result is presented: upon expressing the eddy diffusivity tensor in terms of solutions to auxiliary problems for the adjoint operator, we derive relations between magnetic eddy diffusivity tensors that arise for opposite small-scale flows v(x) and -v(x).

Alexander Andrievsky; Axel Brandenburg; Alain Noullez; Vladislav Zheligovsky

2015-01-19T23:59:59.000Z

197

Forward and Adjoint Simulations of Seismic Wave Propagation on Emerging Large-Scale GPU  

E-Print Network [OSTI]

to subsurface imaging and oil and gas exploration. At the core of these simulations is the modeling of wave impact to the science mission of computational seismologists, we had to port the entire production processing units (GPUs) embedded in HPC clusters. The SPECFEM3D package simulates forward and adjoint coupled

Komatitsch, Dimitri

198

Anomalous Scaling of Structure Functions and Dynamic Constraints on Turbulence Simulations  

E-Print Network [OSTI]

The connection between anomalous scaling of structure functions (intermittency) and numerical methods for turbulence simulations is discussed. It is argued that the computational work for direct numerical simulations (DNS) of fully developed turbulence increases as $Re^{4}$, and not as $Re^{3}$ expected from Kolmogorov's theory, where $Re$ is a large-scale Reynolds number. Various relations for the moments of acceleration and velocity derivatives are derived. An infinite set of exact constraints on dynamically consistent subgrid models for Large Eddy Simulations (LES) is derived from the Navier-Stokes equations, and some problems of principle associated with existing LES models are highlighted.

Victor Yakhot; Katepalli R. Sreenivasan

2005-06-20T23:59:59.000Z

199

Computer Energy Modeling Techniques for Simulation Large Scale Correctional Institutes in Texas  

E-Print Network [OSTI]

using the DOE-2.1E building enegy simulation program to model a 1,000 bed case study correctional unit located in Texas. INTRODUCTION The Texas Department of Criminal Justice (TDCJ) Stephenson unit located in Cuero, Texas was N. Saman, Ph.D., P... building enegy simulation program (LBL 1980; 1981; 1982; 1989; 1994). The second part of the project included evaluating the energy consumption of this prototype unit. This paper presents a methodology that may be used to view and improve simulation...

Heneghan, T.; Haberl, J. S.; Saman, N.; Bou-Saada, T. E.

1996-01-01T23:59:59.000Z

200

Simulation of thermal plant optimization and hydraulic aspects of thermal distribution loops for large campuses  

E-Print Network [OSTI]

turbine and heat recovery steam generator and identified significant potential savings. Finally, the author also used a steam turbine as an example to present a multi-regression method on constructing simulation models by using basic statistics...

Chen, Qiang

2005-08-29T23:59:59.000Z

Note: This page contains sample records for the topic "large eddy simulation" from the National Library of EnergyBeta (NLEBeta).
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201

Simulation of Thermal Plant Optimization and Hydraulic Aspects of Thermal Distribution Loops for Large Campuses  

E-Print Network [OSTI]

is designed specifically for the Texas A&M University utilities system to simulate its operation, to perform thermo-economic cost analysis, and to suggest optimal operation alternatives. Chapter IX is about the simulation of a gas turbine and the heat... separately. ESL-TH-04-05-03 23 Thermodynamic Performance Analysis TABLE 1 provides an annual overall summary of TAMU utilities system energy conversion performance for the year 2002. TABLE 1 TAMU Utilities System Energy Consumption and Production...

Chen, Q.

202

Computed and experimental interactions between eddy structure and dispersed particles in developing free shear layers  

SciTech Connect (OSTI)

We are investigating the interactive process between turbulent flow and dispersed phase particles. We are focusing on the mechanisms that appear to result in a reduction of local turbulent intensity and a corresponding reduction in wall heat transfer and subsequent wall erosion in turbulent solid propellant combustion flow. We apply computational simulations and physical experiments specialized to a developing free shear layer over a rearward facing step and over a parallel splitter plate. The flow configuration evolves in a two-dimensional, steady, combustion and non-combustion turbulent free shear mixing region, with and without particle additives. The computational simulations combine three basic components: gas phase Navier-Stokes solutions, Lagrange particle field solutions and a Monte Carlo technique for the random encounters, forces and accelerations between the two fields. We concentrate here on relatively large sized additive particles (of the order of tens of microns to 100 microns mean diameter). We examine their apparent influence in breaking up the larger, energy bearing eddy structures into smaller structures which are more readily dissipated.

Buckingham, A.C.; Siekhaus, W.J.; Keller, J.O.; Ellzey, J.; Hubbard, G.; Daily, J.W.

1982-05-20T23:59:59.000Z

203

Accelerating solidification process simulation for large-sized system of liquid metal atoms using GPU with CUDA  

SciTech Connect (OSTI)

Molecular dynamics simulation is a powerful tool to simulate and analyze complex physical processes and phenomena at atomic characteristic for predicting the natural time-evolution of a system of atoms. Precise simulation of physical processes has strong requirements both in the simulation size and computing timescale. Therefore, finding available computing resources is crucial to accelerate computation. However, a tremendous computational resource (GPGPU) are recently being utilized for general purpose computing due to its high performance of floating-point arithmetic operation, wide memory bandwidth and enhanced programmability. As for the most time-consuming component in MD simulation calculation during the case of studying liquid metal solidification processes, this paper presents a fine-grained spatial decomposition method to accelerate the computation of update of neighbor lists and interaction force calculation by take advantage of modern graphics processors units (GPU), enlarging the scale of the simulation system to a simulation system involving 10?000?000 atoms. In addition, a number of evaluations and tests, ranging from executions on different precision enabled-CUDA versions, over various types of GPU (NVIDIA 480GTX, 580GTX and M2050) to CPU clusters with different number of CPU cores are discussed. The experimental results demonstrate that GPU-based calculations are typically 9?11 times faster than the corresponding sequential execution and approximately 1.5?2 times faster than 16 CPU cores clusters implementations. On the basis of the simulated results, the comparisons between the theoretical results and the experimental ones are executed, and the good agreement between the two and more complete and larger cluster structures in the actual macroscopic materials are observed. Moreover, different nucleation and evolution mechanism of nano-clusters and nano-crystals formed in the processes of metal solidification is observed with large-sized system.

Jie, Liang [School of Information Science and Engineering, Hunan University, Changshang, 410082 (China)] [School of Information Science and Engineering, Hunan University, Changshang, 410082 (China); Li, KenLi, E-mail: lkl@hnu.edu.cn [School of Information Science and Engineering, Hunan University, Changshang, 410082 (China) [School of Information Science and Engineering, Hunan University, Changshang, 410082 (China); National Supercomputing Center in Changsha, 410082 (China); Shi, Lin [School of Information Science and Engineering, Hunan University, Changshang, 410082 (China)] [School of Information Science and Engineering, Hunan University, Changshang, 410082 (China); Liu, RangSu [School of Physics and Micro Electronic, Hunan University, Changshang, 410082 (China)] [School of Physics and Micro Electronic, Hunan University, Changshang, 410082 (China); Mei, Jing [School of Information Science and Engineering, Hunan University, Changshang, 410082 (China)] [School of Information Science and Engineering, Hunan University, Changshang, 410082 (China)

2014-01-15T23:59:59.000Z

204

Strategies for nested and eddy-permitting state estimation Geoffrey Gebbie,1,2,3  

E-Print Network [OSTI]

Strategies for nested and eddy-permitting state estimation Geoffrey Gebbie,1,2,3 Patrick Heimbach,2 that is nested inside a global state estimate: (1) estimation of open-boundary conditions consistent no fundamental obstacle exists to constraining the large-scale regional circulation nested within a global

Wunsch, Carl

205

Modeling ramp compression experiments using large-scale molecular dynamics simulation.  

SciTech Connect (OSTI)

Molecular dynamics simulation (MD) is an invaluable tool for studying problems sensitive to atomscale physics such as structural transitions, discontinuous interfaces, non-equilibrium dynamics, and elastic-plastic deformation. In order to apply this method to modeling of ramp-compression experiments, several challenges must be overcome: accuracy of interatomic potentials, length- and time-scales, and extraction of continuum quantities. We have completed a 3 year LDRD project with the goal of developing molecular dynamics simulation capabilities for modeling the response of materials to ramp compression. The techniques we have developed fall in to three categories (i) molecular dynamics methods (ii) interatomic potentials (iii) calculation of continuum variables. Highlights include the development of an accurate interatomic potential describing shock-melting of Beryllium, a scaling technique for modeling slow ramp compression experiments using fast ramp MD simulations, and a technique for extracting plastic strain from MD simulations. All of these methods have been implemented in Sandia's LAMMPS MD code, ensuring their widespread availability to dynamic materials research at Sandia and elsewhere.

Mattsson, Thomas Kjell Rene; Desjarlais, Michael Paul; Grest, Gary Stephen; Templeton, Jeremy Alan; Thompson, Aidan Patrick; Jones, Reese E.; Zimmerman, Jonathan A.; Baskes, Michael I. (University of California, San Diego); Winey, J. Michael (Washington State University); Gupta, Yogendra Mohan (Washington State University); Lane, J. Matthew D.; Ditmire, Todd (University of Texas at Austin); Quevedo, Hernan J. (University of Texas at Austin)

2011-10-01T23:59:59.000Z

206

Eddy Correlation Flux Measurement System (ECOR) Handbook  

SciTech Connect (OSTI)

The eddy correlation (ECOR) flux measurement system provides in situ, half-hour measurements of the surface turbulent fluxes of momentum, sensible heat, latent heat, and carbon dioxide (CO2) (and methane at one Southern Great Plains extended facility (SGP EF) and the North Slope of Alaska Central Facility (NSA CF). The fluxes are obtained with the eddy covariance technique, which involves correlation of the vertical wind component with the horizontal wind component, the air temperature, the water vapor density, and the CO2 concentration.

Cook, DR

2011-01-31T23:59:59.000Z

207

Effects of winds and Caribbean eddies on the frequency of Loop Current eddy shedding: A numerical model study  

E-Print Network [OSTI]

of Hispaniola, warm eddies are spun up by the local wind stress curl. This type of eddy drifts southwestward for spin up and drift from Hispaniola is about 100 days. Satellite data indicate the existence

208

Statistical and Directable Methods for Large-Scale Rigid Body Simulation  

E-Print Network [OSTI]

. . . . . . . . 56 4.2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 4.2.2 The Behavior Preference of Objects . . . . . . . . . . . . . . . 57 4.2.3 Dispatch Collision Pairs . . . . . . . . . . . . . . . . . . . . . 59 4.3 Add Simulation....1 The dispatch strategies for three LODs in our system. We implement three di erent methods for solving the narrow-phase collision detection and response. By managing the dispatch strategies, we can adjust the quality over performance rates in di erent LODs...

Hsu, Shu-Wei

2013-05-07T23:59:59.000Z

209

Using cloud resolving model simulations of deep convection to inform cloud parameterizations in large-scale models  

SciTech Connect (OSTI)

Cloud parameterizations in large-scale models struggle to address the significant non-linear effects of radiation and precipitation that arise from horizontal inhomogeneity in cloud properties at scales smaller than the grid box size of the large-scale models. Statistical cloud schemes provide an attractive framework to self-consistently predict the horizontal inhomogeneity in radiation and microphysics because the probability distribution function (PDF) of total water contained in the scheme can be used to calculate these non-linear effects. Statistical cloud schemes were originally developed for boundary layer studies so extending them to a global model with many different environments is not straightforward. For example, deep convection creates abundant cloudiness and yet little is known about how deep convection alters the PDF of total water or how to parameterize these impacts. These issues are explored with data from a 29 day simulation by a cloud resolving model (CRM) of the July 1997 ARM Intensive Observing Period at the Southern Great Plains site. The simulation is used to answer two questions: (a) how well can the beta distribution represent the PDFs of total water relative to saturation resolved by the CRM? (b) how can the effects of convection on the PDF be parameterized? In addition to answering these questions, additional sections more fully describe the proposed statistical cloud scheme and the CRM simulation and analysis methods.

Klein, Stephen A.; Pincus, Robert; Xu, Kuan-man

2003-06-23T23:59:59.000Z

210

A GIS/Simulation Framework for Assessing Change in Water Yield over Large Spatial Scales  

E-Print Network [OSTI]

is as feedstock to produce bioenergy. Producing bioenergy either in the form of ethanol or power is an attractive option since these markets are large enough to absorb the quantities of material that would be generated if thinning was used to reduce the regional risk of fire. Furthermore, the production of bioenergy from

Hargrove, William W.

211

A FINITE ELEMENT APPROACH FOR SIMULATING THE QUENCHING OF LARGE ALUMINIUM COMPRESSOR WHEELS  

E-Print Network [OSTI]

stresses which result from high temperature gradients. This may influence successive machining steps due as shown in Figure 1. A wheel is made out of one massive billet and is quenched in hot water. A 3D-FE model is challenging due to a variety of reasons, such as requiring material data for large temperature range as well

212

Large-scale simulation of steady and time-dependent active suspensions with the force-coupling method  

E-Print Network [OSTI]

We present a new development of the force-coupling method (FCM) to address the accurate simulation of a large number of interacting micro-swimmers. Our approach is based on the squirmer model, which we adapt to the FCM framework, resulting in a method that is suitable for simulating semi-dilute squirmer suspensions. Other effects, such as steric interactions, can be readily considered with our model. We test our method by comparing the velocity field around a single squirmer and the pairwise interactions between two squirmers with exact solutions to the Stokes equations and results given by other numerical methods. We also illustrate our method's ability to describe spheroidal swimmer shapes and biologically-relevant time-dependent swimming gaits. We detail the numerical algorithm used to compute the hydrodynamic coupling between a large collection ($10^4-10 ^5$) of micro-swimmers. Using this methodology, we investigate the emergence of polar order in a suspension of squirmers and show that for large domains,...

Delmotte, Blaise; Plouraboue, Franck; Climent, Eric

2015-01-01T23:59:59.000Z

213

Benchmarking Electron-Cloud Build-Up and Heat-Load Simulations against Large-Hadron-Collider Observations  

E-Print Network [OSTI]

After reviewing the basic features of electron clouds in particle accelerators, the pertinent vacuum-chamber surface properties, and the electron-cloud simulation tools in use at CERN, we report recent observations of electron-cloud phenomena at the Large Hadron Collider (LHC) and ongoing attempts to benchmark the measured LHC vacuum pressure increases and heat loads against electron-cloud build-up simulations aimed at determining the actual surface parameters and at monitoring the so-called scrubbing process. Finally, some other electron-cloud studies related to the LHC are mentioned, and future study plans are described. Presented at MulCoPim2011, Valencia, Spain, 21-23 September 2011.

Dominguez, O; Maury, H; Rumolo, G; Zimmermann, F

2011-01-01T23:59:59.000Z

214

A model for red blood cells in simulations of large-scale blood flows  

E-Print Network [OSTI]

Red blood cells (RBCs) are an essential component of blood. A method to include the particulate nature of blood is introduced here with the goal of studying circulation in large-scale realistic vessels. The method uses a combination of the Lattice Boltzmann method (LBM) to account for the plasma motion, and a modified Molecular Dynamics scheme for the cellular motion. Numerical results illustrate the quality of the model in reproducing known rheological properties of blood as much as revealing the effect of RBC structuring on the wall shear stress, with consequences on the development of cardiovascular diseases.

Simone Melchionna

2011-07-25T23:59:59.000Z

215

On the accuracy of N-body simulations at very large scales  

E-Print Network [OSTI]

We examine the deviation of Cold Dark Matter particle trajectories from the Newtonian result as the size of the region under study becomes comparable to or exceeds the particle horizon. To first order in the gravitational potential, the general relativistic result coincides with the Zel'dovich approximation and hence the Newtonian prediction on all scales. At second order, General Relativity predicts corrections which overtake the corresponding second order Newtonian terms above a certain scale of the order of the Hubble radius. However, since second order corrections are very much suppressed on such scales, we conclude that simulations which exceed the particle horizon but use Newtonian equations to evolve the particles, reproduce the correct trajectories very well. The dominant relativistic corrections to the power spectrum on scales close to the horizon are at most of the order of $\\sim 10^{-5}$ at $z=49$ and $\\sim 10^{-3}$ at $z=0$. The differences in the positions of real space features are affected at a level below $10^{-6}$ at both redshifts. Our analysis also clarifies the relation of N-body results to relativistic considerations.

Gerasimos Rigopoulos; Wessel Valkenburg

2014-11-25T23:59:59.000Z

216

Contoured Surface Eddy Current Inspection System  

DOE Patents [OSTI]

Eddy current inspection of a contoured surface of a workpiece is performed by forming a backing piece of flexible, resiliently yieldable material with a contoured exterior surface conforming in shape to the workpiece contoured surface. The backing piece is preferably cast in place so as to conform to the workpiece contoured surface. A flexible eddy current array probe is attached to the contoured exterior surface of the backing piece such that the probe faces the contoured surface of the workpiece to be inspected when the backing piece is disposed adjacent to the workpiece. The backing piece is then expanded volumetrically by inserting at least one shim into a slot in the backing piece to provide sufficient contact pressure between the probe and the workpiece contoured surface to enable the inspection of the workpiece contoured surface to be performed.

Batzinger, Thomas James (Burnt Hills, NY); Fulton, James Paul (Clifton Park, NY); Rose, Curtis Wayne (Mechanicville, NY); Perocchi, Lee Cranford (Schenectady, NY)

2003-04-08T23:59:59.000Z

217

Statistical Analyses of Scatterplots to Identify Important Factors in Large-Scale Simulations  

SciTech Connect (OSTI)

The robustness of procedures for identifying patterns in scatterplots generated in Monte Carlo sensitivity analyses is investigated. These procedures are based on attempts to detect increasingly complex patterns in the scatterplots under consideration and involve the identification of (1) linear relationships with correlation coefficients, (2) monotonic relationships with rank correlation coefficients, (3) trends in central tendency as defined by means, medians and the Kruskal-Wallis statistic, (4) trends in variability as defined by variances and interquartile ranges, and (5) deviations from randomness as defined by the chi-square statistic. The following two topics related to the robustness of these procedures are considered for a sequence of example analyses with a large model for two-phase fluid flow: the presence of Type I and Type II errors, and the stability of results obtained with independent Latin hypercube samples. Observations from analysis include: (1) Type I errors are unavoidable, (2) Type II errors can occur when inappropriate analysis procedures are used, (3) physical explanations should always be sought for why statistical procedures identify variables as being important, and (4) the identification of important variables tends to be stable for independent Latin hypercube samples.

Kleijnen, J.P.C.; Helton, J.C.

1999-04-01T23:59:59.000Z

218

Eddy current inspection tool. [Patent application  

DOE Patents [OSTI]

A miniaturized inspection tool, for testing and inspection of metal objects in locations with difficult accessibility, which comprises eddy current sensing equipment with a probe coil, and associated coaxial coil cable, oil energizing means, and circuit means responsive to impedance changes in the coil as effected by induced eddy currents in a test object to produce a data output signal proportional to such changes. The coil and cable are slideably received in the utility channel of the flexible insertion tube of a fiberoptic scope. The scope is provided with light transmitting and receiving fiberoptics for viewing through the flexible tube, and articulation means for articulating the distal end of the tube and permitting close control of coil placement relative to a test object. The eddy current sensing equipment includes a tone generator for generating audible signals responsive to the data output signal. In one selected mode of operation, the tone generator responsive to the output signal above a selected level generates a constant single frequency tone for signalling detection of a discontinuity and, in a second selected mode, generates a tone whose frequency is proportional to the difference between the output signal and a predetermined selected threshold level.

Petrini, R.R.; Van Lue, D.F.

1980-10-29T23:59:59.000Z

219

Simulations of a FIR Oscillator with Large Slippage parameter at Jefferson Lab for FIR/UV pump-probe experiments  

SciTech Connect (OSTI)

We previously proposed a dual FEL configuration on the UV Demo FEL at Jefferson Lab that would allow simultaneous lasing at FIR and UV wavelengths. The FIR source would be an FEL oscillator with a short wiggler providing diffraction-limited pulses with pulse energy exceeding 50 microJoules, using the exhaust beam from a UVFEL as the input electron beam. Since the UV FEL requires very short pulses, the input to the FIR FEL is extremely short compared to a slippage length and the usual Slowly Varying Envelope Approximation (SVEA) does not apply. We use a non-SVEA code to simulate this system both with a small energy spread (UV laser off) and with large energy spread (UV laser on).

Benson, Stephen V. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Campbell, L. T. [University of Strathclyde, Glasgow (Great Britain); Daresbury Laboratory and Cockcroft Institute, Warrington (Great Britain); McNeil, B.W.T. [University of Strathclyde, Glasgow (Great Britain); Neil, George R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Shinn, Michelle D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Williams, Gwyn P. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

2014-03-01T23:59:59.000Z

220

HIGH-TEMPERATURE ELECTROLYSIS FOR LARGE-SCALE HYDROGEN AND SYNGAS PRODUCTION FROM NUCLEAR ENERGY – SYSTEM SIMULATION AND ECONOMICS  

SciTech Connect (OSTI)

A research and development program is under way at the Idaho National Laboratory (INL) to assess the technological and scale-up issues associated with the implementation of solid-oxide electrolysis cell technology for efficient high-temperature hydrogen production from steam. This work is supported by the US Department of Energy, Office of Nuclear Energy, under the Nuclear Hydrogen Initiative. This paper will provide an overview of large-scale system modeling results and economic analyses that have been completed to date. System analysis results have been obtained using the commercial code UniSim, augmented with a custom high-temperature electrolyzer module. Economic analysis results were based on the DOE H2A analysis methodology. The process flow diagrams for the system simulations include an advanced nuclear reactor as a source of high-temperature process heat, a power cycle and a coupled steam electrolysis loop. Several reactor types and power cycles have been considered, over a range of reactor outlet temperatures. Pure steam electrolysis for hydrogen production as well as coelectrolysis for syngas production from steam/carbon dioxide mixtures have both been considered. In addition, the feasibility of coupling the high-temperature electrolysis process to biomass and coal-based synthetic fuels production has been considered. These simulations demonstrate that the addition of supplementary nuclear hydrogen to synthetic fuels production from any carbon source minimizes emissions of carbon dioxide during the production process.

J. E. O'Brien; M. G. McKellar; E. A. Harvego; C. M. Stoots

2009-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "large eddy simulation" 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

automated eddy current: Topics by E-print Network  

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

model-assisted POD study. Keywords 2 AUTOMATED ANALYSIS OF EDDY CURRENT SIGNALS IN STEAM GENERATOR TUBE INSPECTION CiteSeer Summary: Abstract: Accurate and consistent...

222

Eddy current measurement of tube element spacing  

DOE Patents [OSTI]

A method of electromagnetically measuring the distance between adjacent tube elements in a heat exchanger. A cylindrical, high magnetic permeability ferrite slug is placed in the tube adjacent the spacing to be measured. A bobbin or annular coil type probe operated in the absolute mode is inserted into a second tube adjacent the spacing to be measured. From prior calibrations on the response of the eddy current coil, the signals from the coil, when sensing the presence of the ferrite slug, are used to determine the spacing between the tubes.

Latham, Wayne Meredith (Forest, VA); Hancock, Jimmy Wade (Lynchburg, VA); Grut, Jayne Marie (Madison Heights, VA)

1998-01-01T23:59:59.000Z

223

Casimir interaction from magnetically coupled eddy currents  

E-Print Network [OSTI]

We study the Casimir interaction due to eddy (Foucault) currents in thick metallic plates. The Drude model is used to describe the optical response of the metal at low frequencies. A repulsive force arises from the electromagnetic coupling between chargeless currents filling the metallic half-spaces. We show that these overdamped modes are entirely responsible for the thermal anomalies of the Casimir force between good conductors. It turns out that the applicability of the Nernst heat theorem (third law of thermodynamics) must be reviewed since the ground state of the coupled metal+field system can become highly degenerate at zero temperature.

Intravaia, Francesco

2009-01-01T23:59:59.000Z

224

Characterization of Caribbean Meso-Scale Eddies Jose M. Lopez  

E-Print Network [OSTI]

Characterization of Caribbean Meso-Scale Eddies Jose M. Lopez Department of Marine Sciences, P-term goal is to improve predictivity of physical, biogeochemical and optical properties of Eastern Caribbean, biological and optical variables across frontal and eddy boundaries in the Eastern Caribbean Sea · To develop

Gilbes, Fernando

225

MEANKINETIC ENERGY,EDDY ENERGY,AND KINETIC ENERGYEXCHANGEBETWEENFLUCTUATIONSAND MEAN  

E-Print Network [OSTI]

MEANKINETIC ENERGY,EDDY ENERGY,AND KINETIC ENERGYEXCHANGEBETWEENFLUCTUATIONSAND MEAN FLOWWITHIN by cornputing three quantities suggested by the theory of turbulence: the nean kinetic energy, the eddy energy, and the energy exchange between the nean and fluctuating portions of the flow field (ca11ed dE/dt). Contours

Luther, Douglas S.

226

MODELING OF EDDY CURRENT LOSS AND TEMPERATURE OF THE MAGNETS  

E-Print Network [OSTI]

the performance of the machine. This paper presents the modeling and analysis of eddy current loss in surfaceMODELING OF EDDY CURRENT LOSS AND TEMPERATURE OF THE MAGNETS IN PERMANENT MAGNET MACHINES ¤ XIAOFENG DING Electrical Engineering Department, Northwestern Polytechnical University, 127 Youyi Xilu #352

Mi, Chunting "Chris"

227

Sensitivity of eddy-induced heat transport to diabatic forcing  

E-Print Network [OSTI]

Abstract. Compensation of the poleward eddy heat transport by the heat transport of an eddy-induced mean meridional overturning cell is a common feature in many eddyresolving ocean models. It has been,argued that this is the result of the weak thermal driving of the ocean. As the actual air/sea coupling is scale dependent, it might be questioned whether the approximation of weak thermal driving is relevant for the oceanic eddy field. In this paper the role of diabatic forcing in modifying eddy-mean flow interaction is investigated. Emphasis has been placed on the sensitivity of the eddy-induced change in heat transport to the sea surface thermal boundary condition. Experiments have been performed with a multilayer isopycnic primitive equation model of an idealized North Atlantic subtropical and subpolar gyre. For different values of the air/sea coupling, solutions with and without transient eddies have been compared. The air/sea coupling mostly affects the upper ocean thermal and velocity fields. A decrease of the coupling timescale pushes the separation point of the midlatitude jet further northward and induces a tight recirculation southwest of the separated jet. These effects are enhanced by the eddies. In the present model there is compensation of the eddy heat transport for sea surface temperature (SST) relaxation times longer than 150 days; a breakdown of the compensation occurs for SST relaxation times shorter than 50 days (the average upper layer depth is 200 m). In between is a transition regime. For strong thermal driving the eddy-induced change in total heat transport is of the same order as the eddy heat transport. 1.

Sybren S. Drijfhout; Royal Netherl; De Bilt

1994-01-01T23:59:59.000Z

228

Evaluation of Detached Eddy Simulation for Turbulent Wake Applications  

E-Print Network [OSTI]

coefficient Cl = lift coefficient Cpb = base pressure coefficient D = square cylinder width d = distance coordinate l j = artificial compression method switch = numerical dissipation parameter l j = flux Jacobian

Roy, Chris

229

BOUNDARY LAYER (BL) THERMAL EDDIES OVER A PINE FOREST FROM CARES 2010  

E-Print Network [OSTI]

BOUNDARY LAYER (BL) THERMAL EDDIES OVER A PINE FOREST FROM CARES 2010 Gunnar Senum and Stephen are three thermal eddies, about 250 meters wide, in the boundary layer. These thermal eddies are formed from the solar heating of the surface and help to form the boundary layer. The eddy updrafts are transporting

230

Eddy-current-damped microelectromechanical switch  

DOE Patents [OSTI]

A microelectromechanical (MEM) device is disclosed that includes a shuttle suspended for movement above a substrate. A plurality of permanent magnets in the shuttle of the MEM device interact with a metal plate which forms the substrate or a metal portion thereof to provide an eddy-current damping of the shuttle, thereby making the shuttle responsive to changes in acceleration or velocity of the MEM device. Alternately, the permanent magnets can be located in the substrate, and the metal portion can form the shuttle. An electrical switch closure in the MEM device can occur in response to a predetermined acceleration-time event. The MEM device, which can be fabricated either by micromachining or LIGA, can be used for sensing an acceleration or deceleration event (e.g. in automotive applications such as airbag deployment or seat belt retraction).

Christenson, Todd R. (Albuquerque, NM); Polosky, Marc A. (Tijeras, NM)

2007-10-30T23:59:59.000Z

231

Eddy-current-damped microelectromechanical switch  

DOE Patents [OSTI]

A microelectromechanical (MEM) device is disclosed that includes a shuttle suspended for movement above a substrate. A plurality of permanent magnets in the shuttle of the MEM device interact with a metal plate which forms the substrate or a metal portion thereof to provide an eddy-current damping of the shuttle, thereby making the shuttle responsive to changes in acceleration or velocity of the MEM device. Alternately, the permanent magnets can be located in the substrate, and the metal portion can form the shuttle. An electrical switch closure in the MEM device can occur in response to a predetermined acceleration-time event. The MEM device, which can be fabricated either by micromachining or LIGA, can be used for sensing an acceleration or deceleration event (e.g. in automotive applications such as airbag deployment or seat belt retraction).

Christenson, Todd R. (Albuquerque, NM); Polosky, Marc A. (Tijeras, NM)

2009-12-15T23:59:59.000Z

232

A majorfeature ofthe VAX-lI is its large virtual address space. This trace-driven simulation scheme evaluates address translation  

E-Print Network [OSTI]

A majorfeature ofthe VAX-lI is its large virtual address space. This trace-driven simulation scheme evaluates address translation hardware that supports thisfeature cost-effectively. Design Trade-Offs in VAX- dress space was a primary goal of VAX architects. (Over- views of VAX architecture are given

Satyanarayanan, Mahadev "Satya"

233

An eddy closure for potential vorticity  

SciTech Connect (OSTI)

The Gent-McWilliams (GM) parameterization is extended to include a direct influence in the momentum equation. The extension is carried out in two stages; an analysis of the inviscid system is followed by an analysis of the viscous system. In the inviscid analysis the momentum equation is modified such that potential vorticity is conserved along particle trajectories following a transport velocity that includes the Bolus velocity in a manner exactly analogous to the continuity and tracer equations. In addition (and in contrast to traditional GM closures), the new formulation of the inviscid momentum equation results in a conservative exchange between potential and kinetic forms of energy. The inviscid form of the eddy closure conserves total energy to within an error proportional to the time derivative of the Bolus velocity. The hypothesis that the viscous term in the momentum equation should give rise to potential vorticity being diffused along isopycnals in a manner analogous to other tracers is examined in detail. While the form of the momentum closure that follows from a strict adherence to this hypothesis is not immediately interpretable within the constructs of traditional momentum closures, three approximations to this hypothesis results in a form of dissipation that is consistent with traditional Laplacian diffusion. The first two approximations are that relative vorticity, not potential vorticity, is diffused along isopyncals and that the flow is in approximate geostrophic balance. An additional approximation to the Jacobian term is required when the dissipation coefficient varies in space. More importantly, the critique of this hypothesis results in the conclusion that the viscosity parameter in the momentum equation should be identical to the tradition GM closure parameter {Kappa}. Overall, we deem the viscous form of the eddy closure for potential vorticity as a viable closure for use in ocean circulation models.

Ringler, Todd D [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

234

Eddy-mean flow interactions in western boundary current jets  

E-Print Network [OSTI]

This thesis examines the nature of eddy-mean flow interactions in western boundary current jets and recirculation gyre dynamics from both theoretical and observational perspectives. It includes theoretical studies of ...

Waterman, Stephanie N

2009-01-01T23:59:59.000Z

235

THE BURGERS PROGRAM FOR FLUID DYNAMICS THE MINTA MARTIN FUND  

E-Print Network [OSTI]

In an effort to make large eddy simulation of scramjet combustors of engineering interest computationally more

Bernstein, Joseph B.

236

Residual sweeping effects in the swept frame of reference in Kinematic Simulations  

E-Print Network [OSTI]

It has been suggested that sweeping effects make Lagrangian properties in Kinematic Simulations (KS) unreliable. Here we show through a novel analysis based upon analysing neighbouring particle trajectories in a frame of reference moving with the large energy contining scales that the residual sweeping error in the turbulent pair diffusivity ($K$) in KS is $e_K\\sim dt/\\tau_s$, where $dt$ is the numerical timestep and $\\tau_s$ is the time scale of the sweeping through local eddies. Thus, provided that $dt\\ll \\tau_s$, then $e_K\\ll 1$ and the Lagrangian properties in KS are reliable.

Malik, Nadeem A

2015-01-01T23:59:59.000Z

237

Predictions of flow through an isothermal serpentine passage with linear eddy-viscosity Reynolds Averaged Navier Stokes models.  

SciTech Connect (OSTI)

Flows with strong curvature present a challenge for turbulence models, specifically eddy viscosity type models which assume isotropy and a linear and instantaneous equilibrium relation between stress and strain. Results obtained from three different codes and two different linear eddy viscosity turbulence models are compared to a DNS simulation in order to gain some perspective on the turbulence modeling capability of SIERRA/Fuego. The Fuego v2f results are superior to the more common two-layer k-e model results obtained with both a commercial and research code in terms of the concave near wall behavior predictions. However, near the convex wall, including the separated region, little improvement is gained using the v2f model and in general the turbulent kinetic energy prediction is fair at best.

Laskowski, Gregory Michael

2005-12-01T23:59:59.000Z

238

NIHAO project I: Reproducing the inefficiency of galaxy formation across cosmic time with a large sample of cosmological hydrodynamical simulations  

E-Print Network [OSTI]

We introduce project NIHAO (Numerical Investigation of a Hundred Astrophysical Objects), a set of 100 cosmological zoom-in hydrodynamical simulations performed using the GASOLINE code, with an improved implementation of the SPH algorithm. The haloes in our study range from dwarf to Milky Way masses, and represent an unbiased sampling of merger histories, concentrations and spin parameters. The particle masses and force softenings are chosen to resolve the mass profile to below 1% of the virial radius at all masses, ensuring that galaxy half-light radii are well resolved. Using the same treatment of star formation and stellar feedback for every object, the simulated galaxies reproduce the observed inefficiency of galaxy formation across cosmic time as expressed through the stellar mass vs halo mass relation, and the star formation rate vs stellar mass relation. We thus conclude that stellar feedback is the chief piece of physics required to limit the efficiency of star formation in galaxies less massive than t...

Wang, Liang; Stinson, Gregory S; Macciò, Andrea V; Penzo, Camilla; Kang, Xi; Keller, Ben W; Wadsley, James

2015-01-01T23:59:59.000Z

239

Mixed Layer Lateral Eddy Fluxes Mediated by Air-Sea Interaction  

E-Print Network [OSTI]

The modulation of air–sea heat fluxes by geostrophic eddies due to the stirring of temperature at the sea surface is discussed and quantified. It is argued that the damping of eddy temperature variance by such air–sea ...

Shuckburgh, Emily

240

Energy pathways and structures of oceanic eddies from the ECCO2 State Estimate and Simplified Models  

E-Print Network [OSTI]

Studying oceanic eddies is important for understanding and predicting ocean circulation and climate variability. The central focus of this dissertation is the energy exchange between eddies and mean ow and banded structures ...

Chen, Ru, Ph. D. Massachusetts Institute of Technology

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "large eddy simulation" 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

New methods for estimating poleward eddy heat transport using satellite altimetry  

E-Print Network [OSTI]

eddy-permitting ocean models (Jayne and Marotzke 2002) and data-assimilation products (Volkov et alNew methods for estimating poleward eddy heat transport using satellite altimetry Shane R. Keating eddy heat transport using satellite altimetry are severely limited by the sparseness

Majda, Andrew J.

242

The effects of juniper removal on rainfall partitioning in the Edwards Aquifer region: large-scale rainfall simulation experiments  

E-Print Network [OSTI]

concentration of high water volumes at the base of vegetation and could provide an important source of moisture in semi-arid landscapes (Martinez-Meza and Whitford 1996). This flow may also be nutrient enriched (Thurow and Hester 1997). Stemflow depends... situations (Bhark and Small 2003). Shrubs may alter infiltration capacity through the addition of leaf litter, which improves soil structure and maintains large pores (Thurow and Hester 1997) as well as through root action (Wilcox 2002). In addition...

Taucer, Philip Isaiah

2006-08-16T23:59:59.000Z

243

Optimisation of an idealised ocean model, stochastic parameterisation of sub-grid eddies  

E-Print Network [OSTI]

An optimisation scheme is developed to accurately represent the sub-grid scale forcing of a high dimensional chaotic ocean system. Using a simple parameterisation scheme, the velocity components of a 30km resolution shallow water ocean model are optimised to have the same climatological mean and variance as that of a less viscous 7.5km resolution model. The 5 day lag-covariance is also optimised, leading to a more accurate estimate of the high resolution response to forcing using the low resolution model. The system considered is an idealised barotropic double gyre that is chaotic at both resolutions. Using the optimisation scheme, we find and apply the constant in time, but spatially varying, forcing term that is equal to the time integrated forcing of the sub-mesoscale eddies. A linear stochastic term, independent of the large-scale flow, with no spatial correlation but a spatially varying amplitude and time scale is used to represent the transient eddies. The climatological mean, variance and 5 day lag-covariance of the velocity from a single high resolution integration is used to provide an optimisation target. No other high resolution statistics are required. Additional programming effort, for example to build a tangent linear or adjoint model, is not required either. The focus of this paper is on the optimisation scheme and the accuracy of the optimised flow. The method can be applied in future investigations into the physical processes that govern barotropic turbulence and it can perhaps be applied to help understand and correct biases in the mean and variance of a more realistic coarse or eddy-permitting ocean model. The method is complementary to current parameterisations and can be applied at the same time without modification.

Fenwick C. Cooper; Laure Zanna

2014-10-21T23:59:59.000Z

244

Simulations of electron-cloud heat load for the cold arcs of the CERN Large Hadron Collider and its high-luminosity upgrade scenarios  

E-Print Network [OSTI]

The heat load generated by an electron cloud in the cold arcs of the Large Hadron Collider (LHC) is a concern for operation near and beyond nominal beam current. We report the results of simulation studies, with updated secondary- emission models, which examine the severity of the electron heat load over a range of possible operation parameters, both for the nominal LHC and for various luminosity-upgrade scenarios, such as the so-called ‘‘full crab crossing’’ and ‘‘early separation’’ schemes, the ‘‘large Piwinski angle’’ scheme, and a variant of the latter providing ‘‘compatibility’’ with the (upgraded) LHCb experiment. The variable parameters considered are the maximum secondary-emission yield, the number of particles per bunch, and the spacing between bunches. In addition, the dependence of the heat load on the longitudinal bunch profile is investigated.

Maury Cuna, H; Zimmermann, F

2012-01-01T23:59:59.000Z

245

Multigrid and Krylov Solvers for Large Scale Finite Element Groundwater Flow Simulations on Distributed Memory Parallel Platforms  

SciTech Connect (OSTI)

In this report we present parallel solvers for large linear systems arising from the finite-element discretization of the three-dimensional steady-state groundwater flow problem. Our solvers are based on multigrid and Krylov subspace methods. The parallel implementation is based on a domain decomposition strategy with explicit message passing using NX and MPI libraries. We have tested our parallel implementations on the Intel Paragon XP/S 150 supercomputer using up to 1024 parallel processors and on other parallel platforms such as SGI/Power Challenge Array, Cray/SGI Origin 2000, Convex Exemplar SPP-1200, and IBM SP using up to 64 processors. We show that multigrid can be a scalable algorithm on distributed memory machines. We demonstrate the effectiveness of parallel multigrid based solvers by solving problems requiring more than 70 million nodes in less than a minute. This is more than 25 times faster than the diagonal preconditioned conjugate gradient method which is one of the more popular methods for large sparse linear systems. Our results also show that multigrid as a stand alone solver works best for problems with smooth coefficients, but for rough coefficients it is best used as a preconditioner for a Krylov subspace method such as the conjugate gradient method. We show that even for extremely heterogeneous systems the multigrid pre-conditioned conjugate gradient method is at least 10 times faster than the diagonally preconditioned conjugate gradient method.

Mahinthakumar, K.

1997-01-01T23:59:59.000Z

246

EddyViscosity Time Reversing Waves a Dissipative Environment  

E-Print Network [OSTI]

where linear shallow water speed is given o o . The kinematic viscosity denoted parameter ratio been shown [6] nonlinear (inviscid) shallow water waves pres­ ence a random topography and alsoEddyViscosity Time Reversing Waves a Dissipative Environment Josselin Garnier Laboratoire

Garnier, Josselin

247

Probability of detection models for eddy current NDE methods  

SciTech Connect (OSTI)

The development of probability of detection (POD) models for a variety of nondestructive evaluation (NDE) methods is motivated by a desire to quantify the variability introduced during the process of testing. Sources of variability involved in eddy current methods of NDE include those caused by variations in liftoff, material properties, probe canting angle, scan format, surface roughness and measurement noise. This thesis presents a comprehensive POD model for eddy current NDE. Eddy current methods of nondestructive testing are used widely in industry to inspect a variety of nonferromagnetic and ferromagnetic materials. The development of a comprehensive POD model is therefore of significant importance. The model incorporates several sources of variability characterized by a multivariate Gaussian distribution and employs finite element analysis to predict the signal distribution. The method of mixtures is then used for estimating optimal threshold values. The research demonstrates the use of a finite element model within a probabilistic framework to the spread in the measured signal for eddy current nondestructive methods. Using the signal distributions for various flaw sizes the POD curves for varying defect parameters have been computed. In contrast to experimental POD models, the cost of generating such curves is very low and complex defect shapes can be handled very easily. The results are also operator independent.

Rajesh, S.N.

1993-04-30T23:59:59.000Z

248

CgWind: A high-order accurate simulation tool for wind turbines and wind farms  

SciTech Connect (OSTI)

CgWind is a high-fidelity large eddy simulation (LES) tool designed to meet the modeling needs of wind turbine and wind park engineers. This tool combines several advanced computational technologies in order to model accurately the complex and dynamic nature of wind energy applications. The composite grid approach provides high-quality structured grids for the efficient implementation of high-order accurate discretizations of the incompressible Navier-Stokes equations. Composite grids also provide a natural mechanism for modeling bodies in relative motion and complex geometry. Advanced algorithms such as matrix-free multigrid, compact discretizations and approximate factorization will allow CgWind to perform highly resolved calculations efficiently on a wide class of computing resources. Also in development are nonlinear LES subgrid-scale models required to simulate the many interacting scales present in large wind turbine applications. This paper outlines our approach, the current status of CgWind and future development plans.

Chand, K K; Henshaw, W D; Lundquist, K A; Singer, M A

2010-02-22T23:59:59.000Z

249

On the simulation of shock-driven material mixing in high-Re flows (u)  

SciTech Connect (OSTI)

Implicit large eddy simulation proposes to effectively rely on the use of subgrid modeling and filtering provided implicitly by physics capturing numerics. Extensive work has demonstrated that predictive simulations of turbulent velocity fields are possible using a class of high resolution, non-oscillatory finite-volume (NFV) numerical algorithms. Truncation terms associated with NFV methods implicitly provide subgrid models capable of emulating the physical dynamics of the unresolved turbulent velocity fluctuations by themselves. The extension of the approach to the substantially more difficult problem of under-resolved material mixing by an under-resolved velocity field has not yet been investigated numerically, nor are there any theories as to when the methodology may be expected to be successful. Progress in addressing these issues in studies of shock-driven scalar mixing driven by Ritchmyer-Meshkov instabilities will be reported in the context of ongoing simulations of shock-tube laboratory experiments.

Grinstein, Fernando F [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

250

EDDY CURRENT MODEL FOR NONDESTRUCTIVE EVALUATION ...  

E-Print Network [OSTI]

large power transformers [15,18,26]. In [20], Nédélec and Wolf ..... where (˜?˜u)Di is understood to take limit of ˜?˜u from inside Di. This means ˜?˜u·n = 0 on Si for ...

2015-04-05T23:59:59.000Z

251

SCORPIO: A Scalable Two-Phase Parallel I/O Library With Application To A Large Scale Subsurface Simulator  

SciTech Connect (OSTI)

Inefficient parallel I/O is known to be a major bottleneck among scientific applications employed on supercomputers as the number of processor cores grows into the thousands. Our prior experience indicated that parallel I/O libraries such as HDF5 that rely on MPI-IO do not scale well beyond 10K processor cores, especially on parallel file systems (like Lustre) with single point of resource contention. Our previous optimization efforts for a massively parallel multi-phase and multi-component subsurface simulator (PFLOTRAN) led to a two-phase I/O approach at the application level where a set of designated processes participate in the I/O process by splitting the I/O operation into a communication phase and a disk I/O phase. The designated I/O processes are created by splitting the MPI global communicator into multiple sub-communicators. The root process in each sub-communicator is responsible for performing the I/O operations for the entire group and then distributing the data to rest of the group. This approach resulted in over 25X speedup in HDF I/O read performance and 3X speedup in write performance for PFLOTRAN at over 100K processor cores on the ORNL Jaguar supercomputer. This research describes the design and development of a general purpose parallel I/O library, SCORPIO (SCalable block-ORiented Parallel I/O) that incorporates our optimized two-phase I/O approach. The library provides a simplified higher level abstraction to the user, sitting atop existing parallel I/O libraries (such as HDF5) and implements optimized I/O access patterns that can scale on larger number of processors. Performance results with standard benchmark problems and PFLOTRAN indicate that our library is able to maintain the same speedups as before with the added flexibility of being applicable to a wider range of I/O intensive applications.

Sreepathi, Sarat [ORNL] [ORNL; Sripathi, Vamsi [Intel Corporation] [Intel Corporation; Mills, Richard T [ORNL] [ORNL; Hammond, Glenn [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Mahinthakumar, Kumar [North Carolina State University] [North Carolina State University

2013-01-01T23:59:59.000Z

252

The Canary Eddy Corridor: A major pathway for long-lived eddies in the subtropical North Atlantic  

E-Print Network [OSTI]

corridor, whose source is the flow perturbation of the Canary Current and the Trade Winds at the Canary westward- propagating eddy corridors were also detected: two small corridors north and south of the Azores Front; a small zonal corridor located near 31 % oN, south of the island of Madeira; and a small corridor

Dong, Changming "Charles"

253

LARGE SCALE SIMULATIONS OF THE MECHANCIAL PROPERTIES OF LAYERED TRANSITION METAL TERNARY COMPOUNDS FOR FOSSIL ENERGY POWER SYSTEM APPLICATIONS  

SciTech Connect (OSTI)

Advanced materials with applications in extreme conditions such as high temperature, high pressure, and corrosive environments play a critical role in the development of new technologies to significantly improve the performance of different types of power plants. Materials that are currently employed in fossil energy conversion systems are typically the Ni-based alloys and stainless steels that have already reached their ultimate performance limits. Incremental improvements are unlikely to meet the more stringent requirements aimed at increased efficiency and reduce risks while addressing environmental concerns and keeping costs low. Computational studies can lead the way in the search for novel materials or for significant improvements in existing materials that can meet such requirements. Detailed computational studies with sufficient predictive power can provide an atomistic level understanding of the key characteristics that lead to desirable properties. This project focuses on the comprehensive study of a new class of materials called MAX phases, or Mn+1AXn (M = a transition metal, A = Al or other group III, IV, and V elements, X = C or N). The MAX phases are layered transition metal carbides or nitrides with a rare combination of metallic and ceramic properties. Due to their unique structural arrangements and special types of bonding, these thermodynamically stable alloys possess some of the most outstanding properties. We used a genomic approach in screening a large number of potential MAX phases and established a database for 665 viable MAX compounds on the structure, mechanical and electronic properties and investigated the correlations between them. This database if then used as a tool for materials informatics for further exploration of this class of intermetallic compounds.

Ching, Wai-Yim

2014-12-31T23:59:59.000Z

254

Rossby wave radiation by an eddy on the polar beta-plane  

E-Print Network [OSTI]

Results from the laboratory experiments on the evolution of vortices (eddies) generated in a rotating tank with topographic beta-effect are presented. The surface elevation and velocity fields are measured by the Altimetric Imaging Velocimetry. The experiments are supplemented by shallow water numerical simulations as well as a linear theory which describes the Rossby wave radiation by travelling vortices. The cyclonic vortices observed in the experiments travel to the northwest and continuously radiate Rossby waves. Measurements show that initially axisymmetric vortices develop a dipolar component which enables them to perform translational motion. A pattern of alternating zonal jets to the west of the vortex is created by Rossby waves with approximately zonal crests. Energy spectra of the flows in the wavenumber space indicate that a wavenumber similar to that introduced by Rhines for turbulent flows on the beta-plane can be introduced here. The wavenumber is based on the translational speed of a vortex rat...

Zhang, Yang

2015-01-01T23:59:59.000Z

255

First-principles studies on vacancy-modified interstitial diffusion mechanism of oxygen in nickel, associated with large-scale atomic simulation techniques  

SciTech Connect (OSTI)

This paper is concerned with the prediction of oxygen diffusivities in fcc nickel from first-principles calculations and large-scale atomic simulations. Considering only the interstitial octahedral to tetrahedral to octahedral minimum energy pathway for oxygen diffusion in fcc lattice, greatly underestimates the migration barrier and overestimates the diffusivities by several orders of magnitude. The results indicate that vacancies in the Ni-lattice significantly impact the migration barrier of oxygen in nickel. Incorporation of the effect of vacancies results in predicted diffusivities consistent with available experimental data. First-principles calculations show that at high temperatures the vacancy concentration is comparable to the oxygen solubility, and there is a strong binding energy and a redistribution of charge density between the oxygen atom and vacancy. Consequently, there is a strong attraction between the oxygen and vacancy in the Ni lattice, which impacts diffusion.

Fang, H. Z.; Shang, S. L.; Wang, Y.; Liu, Z. K. [National Energy Technology Laboratory Regional University Alliance, U.S. Department of Energy, Pittsburgh, Pennsylvania 15236 (United States); Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Alfonso, D.; Alman, D. E. [National Energy Technology Laboratory Regional University Alliance, U.S. Department of Energy, Pittsburgh, Pennsylvania 15236 (United States); National Energy Technology Laboratory, U.S. Department of Energy, Pittsburgh, Pennsylvania 15236 (United States); Shin, Y. K.; Zou, C. Y.; Duin, A. C. T. van [National Energy Technology Laboratory Regional University Alliance, U.S. Department of Energy, Pittsburgh, Pennsylvania 15236 (United States); Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Lei, Y. K.; Wang, G. F. [National Energy Technology Laboratory Regional University Alliance, U.S. Department of Energy, Pittsburgh, Pennsylvania 15236 (United States); Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pennsylvania 15261 (United States)

2014-01-28T23:59:59.000Z

256

Automated detection and location of indications in eddy current signals  

DOE Patents [OSTI]

A computer implemented information extraction process that locates and identifies eddy current signal features in digital point-ordered signals, signals representing data from inspection of test materials, by enhancing the signal features relative to signal noise, detecting features of the signals, verifying the location of the signal features that can be known in advance, and outputting information about the identity and location of all detected signal features.

Brudnoy, David M. (Albany, NY); Oppenlander, Jane E. (Burnt Hills, NY); Levy, Arthur J. (Schenectady, NY)

2000-01-01T23:59:59.000Z

257

Alcian Blue Cartilage Staining Beatrice Jegalian & Eddy M. De Robertis  

E-Print Network [OSTI]

Alcian Blue Cartilage Staining Beatrice Jegalian & Eddy M. De Robertis (Cell 71, 901-910, 1992) 1 will require more time) in 0.05% Alcian blue 8GX (Fisher) in 5% acetic acid. 6. Wash embryos in 5% acetic acid Alcian Blue 8 g NaCl 0.05% Alcian blue 8GX .2 g KCl 5% acetic acid 1.44 g Na2HPO4 water .24 g KH2PO4 800

De Robertis, Eddy M.

258

V-TOUGH: An enhanced version of the TOUGH code for the thermal and hydrologic simulation of large-scale problems in nuclear waste isolation  

SciTech Connect (OSTI)

The TOUGH code developed at Lawrence Berkeley Laboratory (LBL) is being extensively used to numerically simulate the thermal and hydrologic environment around nuclear waste packages in the unsaturated zone for the Yucca Mountain Project. At the Lawrence Livermore National Laboratory (LLNL) we have rewritten approximately 80 percent of the TOUGH code to increase its speed and incorporate new options. The geometry of many problems requires large numbers of computational elements elements in order to realistically model detailed physical phenomena, and, as a result, large amounts of computer time are needed. In order to increase the speed of the code we have incorporated fast linear equation solvers, vectorization of substantial portions of code, improved automatic time stepping, and implementation of table look-up for the steam table properties. These enhancements have increased the speed of the code for typical problems by a factor of 20 on the Cray 2 computer. In addition to the increase in computational efficiency we have added several options: vapor pressure lowering; equivalent continuum treatments of fractures; energy and material volumetric, mass and flux accounting; and Stefan-Boltzmann radiative heat transfer. 5 refs.

Nitao, J.J.

1989-11-06T23:59:59.000Z

259

Method and apparatus for correcting eddy current signal voltage for temperature effects  

DOE Patents [OSTI]

An apparatus and method for measuring physical characteristics of an electrically conductive material by the use of eddy-current techniques and compensating measurement errors caused by changes in temperature includes a switching arrangement connected between primary and reference coils of an eddy-current probe which allows the probe to be selectively connected between an eddy current output oscilloscope and a digital ohm-meter for measuring the resistances of the primary and reference coils substantially at the time of eddy current measurement. In this way, changes in resistance due to temperature effects can be completely taken into account in determining the true error in the eddy current measurement. The true error can consequently be converted into an equivalent eddy current measurement correction.

Kustra, Thomas A. (N. Huntingdon, PA); Caffarel, Alfred J. (Pittsburgh, PA)

1990-01-01T23:59:59.000Z

260

Atmospheric Moisture Budget and Spatial Resolution Dependence of Precipitation Extremes in Aquaplanet Simulations  

SciTech Connect (OSTI)

This study investigates the resolution dependency of precipitation extremes in an aqua-planet framework. Strong resolution dependency of precipitation extremes is seen over both tropics and extra-tropics, and the magnitude of this dependency also varies with dynamical cores. Moisture budget analyses based on aqua-planet simulations with the Community Atmosphere Model (CAM) using the Model for Prediction Across Scales (MPAS) and High Order Method Modeling Environment (HOMME) dynamical cores but the same physics parameterizations suggest that during precipitation extremes moisture supply for surface precipitation is mainly derived from advective moisture convergence. The resolution dependency of precipitation extremes mainly originates from advective moisture transport in the vertical direction. At most vertical levels over the tropics and in the lower atmosphere over the subtropics, the vertical eddy transport of mean moisture field dominates the contribution to precipitation extremes and its resolution dependency. Over the subtropics, the source of moisture, its associated energy, and the resolution dependency during extremes are dominated by eddy transport of eddies moisture at the mid- and upper-troposphere. With both MPAS and HOMME dynamical cores, the resolution dependency of the vertical advective moisture convergence is mainly explained by dynamical changes (related to vertical velocity or omega), although the vertical gradients of moisture act like averaging kernels to determine the sensitivity of the overall resolution dependency to the changes in omega at different vertical levels. The natural reduction of variability with coarser resolution, represented by areal data averaging (aggregation) effect, largely explains the resolution dependency in omega. The thermodynamic changes, which likely result from non-linear feedback in response to the large dynamical changes, are small compared to the overall changes in dynamics (omega). However, after excluding the data aggregation effect in omega, thermodynamic changes become relatively significant in offsetting the effect of dynamics leading to reduce differences between the simulated and aggregated results. Compared to MPAS, the simulated stronger vertical motion with HOMME also results in larger resolution dependency. Compared to the simulation at fine resolution, the vertical motion during extremes is insufficiently resolved/parameterized at the coarser resolution even after accounting for the natural reduction in variability with coarser resolution, and this is more distinct in the simulation with HOMME. To reduce uncertainties in simulated precipitation extremes, future development in cloud parameterizations must address their sensitivity to spatial resolution as well as dynamical cores.

Yang, Qing; Leung, Lai-Yung R.; Rauscher, Sara; Ringler, Todd; Taylor, Mark

2014-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "large eddy simulation" 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

Simulating Collisions for Hydrokinetic Turbines  

SciTech Connect (OSTI)

Evaluations of blade-strike on an axial-flow Marine Hydrokinetic turbine were conducted using a conventional methodology as well as an alternative modeling approach proposed in the present document. The proposed methodology integrates the following components into a Computa- tional Fluid Dynamics (CFD) model: (i) advanced eddy-resolving flow simulations, (ii) ambient turbulence based on field data, (iii) moving turbine blades in highly transient flows, and (iv) Lagrangian particles to mimic the potential fish pathways. The sensitivity of blade-strike prob- ability to the following conditions was also evaluated: (i) to the turbulent environment, (ii) to fish size and (iii) to mean stream flow velocity. The proposed methodology provided fraction of collisions and offered the capability of analyzing the causal relationships between the flow envi- ronment and resulting strikes on rotating blades. Overall, the conventional methodology largely overestimates the probability of strike, and lacks the ability to produce potential fish and aquatic biota trajectories as they interact with the rotating turbine. By using a set of experimental corre- lations of exposure-response of living fish colliding on moving blades, the occurrence, frequency and intensity of the particle collisions was next used to calculate the survival rate of fish crossing the MHK turbine. This step indicated survival rates always greater than 98%. Although the proposed CFD framework is computationally more expensive, it provides the advantage of evaluating multiple mechanisms of stress and injury of hydrokinetic turbine devices on fish.

Richmond, Marshall C.; Romero Gomez, Pedro DJ; Rakowski, Cynthia L.

2013-10-01T23:59:59.000Z

262

Remote Field Eddy Current Probes for the Detection of Stress Corrosion in Transmission Pipelines  

SciTech Connect (OSTI)

Magnetic flux leakage (MFL) is a technique used widely in non-destructive testing (NDT) of natural gas and petroleum transmission pipelines. This inspection method relies on magnetizing the pipe-wall in axial direction. The MFL inspection tool is equipped with an array of Hall sensors located around the circumference of the pipe, which registers the flux leakage caused by any defects present in the pipe-wall. Currently, the tool magnetizes the pipewall in axial direction making it largely insensitive to axially oriented defects. One type of defect, which is of a growing concern in the gas and petroleum industry is the stress corrosion crack (SCC). The SCCs are a result of aging, corrosion, fatigue and thermal stresses. SCCs are predominantly axially oriented and are extremely tight, which makes them impossible to be detected using current inspection technology. A possible solution to this problem is to utilize the remote field eddy current (RFEC) effect to detect axially oriented defects. The RFEC method has been widely used in industry in the inspection of tubular products. The method uses a pair of excitation and pick-up coils. The pick-up coil located in the remote field region, usually two, three pipe-diameters away from the excitation coil. With RFEC the presence of defects is detected by the disturbance in the phase of the signal measured by the pick-up coil relative to that of the excitation coil. Unlike conventional eddy current testing the RFEC method is sensitive to defects on the exterior of the inspected product, which makes it a good candidate for the development of in-line inspection technology. This work focuses on the development of non-destructive testing technique, which uses remote field eddy currents induced by rotating magnetic field (RMF). A major advantage of the RMF is that it makes possible to not only detect a defect but also localize its position in circumferential direction. Also, it could potentially allow detection of defects, regardless of their shape and orientation. In this work the RFEC-RMF technique is investigated and is shown to be a useful tool in the detection of axially oriented, circumferentially oriented and skewed notches, SCCs and round defects. Finally, a data acquisition system is designed, capable of performing the RFEC-RMF measurements automatically.

Plamen Alexandroz Ivanov

2002-08-27T23:59:59.000Z

263

A study of RELAP5/MOD2 and RELAP5/MOD3 predictions of a small break LOCA simulation conducted at the ROSA-IV Large Scale Test Facility  

E-Print Network [OSTI]

)pl / ? DE -Upp r Head Spray Nozzle rVent Valve Simulator Line Hot Leo Upper Plenum Leak Line r9 Core normal flow transient 'low ECCH Induction E-l EltO QtQ EltC] El Lower Plenum Figure 4. Pressure Vessel 12 Table II Primary... simulation codes RELAP5/MOD2 and RELAP5/MOD3 were utilized to calculate the phenomena which occurred during a small break LOCA simulation conducted at the ROSA-IV Large Scale Test Facility. The transient scenario was a 5% break in the cold leg with a loss...

Sloan, Sandra Mernell

1990-01-01T23:59:59.000Z

264

The Role of Eddy-Tansport in the Thermohaline Circulation  

SciTech Connect (OSTI)

Several research themes were developed during the course of this project. (1) Low-frequency oceanic varibility; (2) The role of eddies in the Antarctic Circumpolar Current (ACC) region; (3) Deep stratification and the overturning circulation. The key findings were as follows: (1) The stratification below the main thermocline (at about 500m) is determined in the circumpolar region and then communicated to the enclosed portions of the oceans through the overturning circulation. (2) An Atlantic pole-to-pole overturning circulation can be maintained with very small interior mixing as long as surface buoyancy values are shared between the northern North Atlantic and the ACC region.

Dr. Paola Cessi

2011-11-17T23:59:59.000Z

265

Methods of and apparatus for levitating an eddy current probe  

DOE Patents [OSTI]

An eddy current probe is supported against the force of gravity with an air earing while being urged horizontally toward the specimen being examined by a spring and displaced horizontally against the force of the spring pneumatically. The pneumatic displacement is accomplished by flowing air between a plenum chamber fixed with respect to the probe and the surface of the specimen. In this way, the surface of the specimen can be examined without making mechanical contact therewith while precisely controlling the distance at which the probe stands-off from the surface of the specimen.

Stone, William J. (Kansas City, MO)

1988-05-03T23:59:59.000Z

266

New Eddy Correlation System for ARM SGP Site  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the Contributions andDataNational Library of1,Department ofNew Eddy Correlation System

267

Eddy Amplitudes in Baroclinic Turbulence Driven by Nonzonal Mean Flow: Shear Dispersion of Potential Vorticity  

E-Print Network [OSTI]

Sciences, New York University, New York, New York (Manuscript received 13 April 2006, in final form 17 July of potential vorticity (the source of eddy energy) in the zonal and meridional directions are fundamentally. The resulting flux is orders of magnitude higher than in the cross-jet direction, and thus eddy energies driven

Smith, K. Shafer

268

Phenomenology for the decay of energy-containing eddies in homogeneous MHD turbulence  

E-Print Network [OSTI]

Phenomenology for the decay of energy-containing eddies in homogeneous MHD turbulence Murshed of simple, one-point phenomenological models for the decay of energy-containing eddies phenomenology has been previously verified against experiments in wind tunnels, and certain experimentally

Oughton, Sean

269

Anticyclonic and cyclonic eddies of subtropical origin in the subantarctic zone south of Africa  

E-Print Network [OSTI]

Anticyclonic and cyclonic eddies of subtropical origin in the subantarctic zone south of Africa and cyclonic eddies of subtropical origin in the subantarctic zone south of Africa, J. Geophys. Res., 116, C into the Southern Ocean. The oceanic domain south of South Africa, where the Agulhas Current system abuts

Boyer, Edmond

270

Eddy impacts on the Florida Current E. Frajka-Williams,1  

E-Print Network [OSTI]

Eddy impacts on the Florida Current E. Frajka-Williams,1 W. E. Johns,2 C. S. Meinen,3 L. M. Beal,2. Meinen, L. M. Beal, and S. A. Cunningham (2013), Eddy impacts on the Florida Current, Geophys. Res. Lett, the FC is coherent with local winds [Schott et al., 1988; Atkinson et al., 2010; Rousset and Beal, 2011

271

Barotropic Impacts of Surface Friction on Eddy Kinetic Energy and Momentum Fluxes: An Alternative to the Barotropic Governor  

E-Print Network [OSTI]

Barotropic Impacts of Surface Friction on Eddy Kinetic Energy and Momentum Fluxes: An Alternative energy decreases, a response that is inconsistent with the conventional barotropic governor mechanism on eddy momentum fluxes and eddy kinetic energy. Analysis of the pseudomomentum budget shows

Garfinkel, Chaim I.

272

Performance of powder-filled evacuated panel insulation in a manufactured home roof cavity: Tests in the Large Scale Climate Simulator  

SciTech Connect (OSTI)

A full-scale section of half the top of a single-wide manufactured home has been studied in the Large Scale Climate Simulator (LSCS) at the Oak Ridge National Laboratory. A small roof cavity with little room for insulation at the eaves is often the case with single-wide units and limits practical ways to improve thermal performance. The purpose of the current tests was to obtain steady-state performance data for the roof cavity of the manufactured home test section when the roof cavity was insulated with fiberglass batts, blown-in rock wool insulation or combinations of these insulations and powder-filled evacuated panel (PEP) insulation. Four insulation configurations were tested: (A) a configuration with two layers of nominal R{sub US}-7 h {center_dot} ft{sup 2} {center_dot} F/BTU (R{sub SI}-1.2 m{sup 2} {center_dot} K/W) fiberglass batts; (B) a layer of PEPs and one layer of the fiberglass batts; (C) four layers of the fiberglass batts; and (D) an average 4.1 in. (10.4 cm) thick layer of blown-in rock wool at an average density of 2.4 lb/ft{sup 3} (38 kg/m{sup 3}). Effects of additional sheathing were determined for Configurations B and C. With Configuration D over the ceiling, two layers of expanded polystyrene (EPS) boards, each about the same thickness as the PEPs, were installed over the trusses instead of the roof. Aluminum foils facing the attic and over the top layer of EPS were added. The top layer of EPS was then replaced by PEPs.

Petrie, T.W.; Kosny, J.; Childs, P.W.

1996-03-01T23:59:59.000Z

273

Direct numerical simulation of turbulent reacting flows  

SciTech Connect (OSTI)

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

274

Large-Eddy Observation of Post-Cold-Frontal Continental Stratocumulus  

E-Print Network [OSTI]

More studies on the dynamics of marine stratus and stratocumulus clouds have been performed than comparable studies on continental stratocumulus. Therefore, to increase the number of observations of continental stratocumulus ...

Mechem, David B.; Kogan, Yefim L.; Schultz, David M.

2010-10-01T23:59:59.000Z

275

The role of large eddy fluctuations in the Madison Dynamo Experiment  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched Ferromagnetism in Layered NbS2 andThe MolecularPlaceTheofThebattery materialsMHDLARGE

276

Workshops and problems for benchmarking eddy current codes  

SciTech Connect (OSTI)

A series of six workshops was held in 1986 and 1987 to compare eddy current codes, using six benchmark problems. The problems included transient and steady-state ac magnetic fields, close and far boundary conditions, magnetic and non-magnetic materials. All the problems were based either on experiments or on geometries that can be solved analytically. The workshops and solutions to the problems are described. Results show that many different methods and formulations give satisfactory solutions, and that in many cases reduced dimensionality or coarse discretization can give acceptable results while reducing the computer time required. A second two-year series of TEAM (Testing Electromagnetic Analysis Methods) workshops, using six more problems, is underway. 12 refs., 15 figs., 4 tabs.

Turner, L.R.; Davey, K.; Ida, N.; Rodger, D.; Kameari, A.; Bossavit, A.; Emson, C.R.I.

1988-08-01T23:59:59.000Z

277

Surface Characterization of Stainless Steel Part by Eddy Current  

SciTech Connect (OSTI)

The Pacific Northwest National Laboratory (PNNL) has nearly a 40 year history of research and development in the field of nondestructive evaluation (NDE). One area of NDE expertise at PNNL is electromagnetic testing which includes a field of eddy current testing (ET). One benefit is that ET can typically be performed at high speeds, and as a result has found many applications in process monitoring and poduction lines. ET has been used in the nuclear, aerospace, and automotive industries for many years. Et technology lends itself well to the detection of near-surface or surface breaking defects such as surface scratches. This paper provides an overview of theory regarding the usage of ET, selected application studies performed by PNNL, a safety analysis, and a wrtie up pertaining to the operations of ET to detect surface scratches.

Andersen, Eric S.; Hockey, Ronald L.; Prince, James M.; Good, Morris S.

2003-10-01T23:59:59.000Z

278

Impact of mesoscale eddies on water transport between the Pacific Ocean and the Bering Sea  

E-Print Network [OSTI]

Sea surface height anomalies observed by satellites in 1993--2012 are combined with simulation and observations by surface drifters and Argo floats to study water flow pattern in the Near Strait (NS) connected the Pacific Ocean with the Bering Sea. Daily Lagrangian latitudinal maps, computed with the AVISO surface velocity field, and calculation of the transport across the strait show that the flow through the NS is highly variable and controlled by mesoscale and submesoscale eddies in the area. On the seasonal scale, the flux through the western part of the NR is negatively correlated with the flux through its eastern part ($r=-0.93$). On the interannual time scale, a significant positive correlation ($r=0.72$) is diagnosed between the NS transport and the wind stress in winter. Increased southward component of the wind stress decreases the northward water transport through the strait. Positive wind stress curl over the strait area in winter--spring generates the cyclonic circulation and thereby enhances the...

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

2013-01-01T23:59:59.000Z

279

A quadrature-based LES/transported probability density function approach for  

E-Print Network [OSTI]

and inexpensive pathway for scramjet design. In the recent past, the large eddy simulation (LES) methodology has

Raman, Venkat

280

RELAP5/MOD3 simulation of the loss of residual heat removal during midloop operation experiment conducted at the ROSA-IV/ Large Scale Test Facility  

E-Print Network [OSTI]

The modeling of the complex thermal hydraulics Of reactor systems involves the use Of experimental test systems as well as numerical codes. A simulation of the loss of residual heat removal (RHR) during midloop operations was performed using...

Banerjee, Sibashis Sanatkumar

2012-06-07T23:59:59.000Z

Note: This page contains sample records for the topic "large eddy simulation" 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

This is an author-deposited version published in : http://oatao.univ-toulouse.fr/ Eprints ID : 8579  

E-Print Network [OSTI]

-Dominik and Poinsot, Thierry Acoustic and Large Eddy Simulation studies of azimuthal modes in annular combustion-oatao@listes.diff.inp-toulouse.fr #12;Acoustic and Large Eddy Simulation studies of azimuthal modes in annular combustion chambers. P) Large Eddy Simulation (LES) methods and (2) acoustic solvers. These strong com- bustion instabilities

Mailhes, Corinne

282

Subduction in an eddy-resolving state estimate of the northeast Atlantic Ocean  

E-Print Network [OSTI]

Relatively little is known about the role of eddies in controlling subduction in the eastern half of the subtropical gyre. Here, a new tool to study the eastern North Atlantic Ocean is created by combining a regional, ...

Gebbie, Geoffrey Alexander, 1975-

2004-01-01T23:59:59.000Z

283

Understanding the Regional Variability of Eddy Diffusivity in the Pacific Sector of the Southern Ocean  

E-Print Network [OSTI]

A diagnostic framework is presented, based on the Nakamura effective diffusivity, to investigate the regional variation in eddy diffusivity. Comparison of three different diffusivity calculations enables the effects of ...

Shuckburgh, Emily

284

Nonlinear equilibration of baroclinic eddies : the role of boundary layer processes and seasonal forcing  

E-Print Network [OSTI]

In this thesis, the influence of boundary layer processes and seasonal forcing on baroclinic eddy equilibration is studied to understand how the baroclinic adjustment is modified when taking into account these two factors. ...

Zhang, Yang, Ph. D. Massachusetts Institute of Technology

2009-01-01T23:59:59.000Z

285

A comparison of eddy current effects in a single sided magnetic thrust bearing  

E-Print Network [OSTI]

finite element studies of magnetic thrust bearings using static bench testing procedures to investigate configurations that promote eddy current reduction. Several rotor/stator configurations, including solid metal, laminated washers, tapewound lam...

DeWeese, Randall Thomas

1996-01-01T23:59:59.000Z

286

Eddy covariance flux measurements of pollutant gases in urban Mexico City  

E-Print Network [OSTI]

Eddy covariance (EC) flux measurements of the atmosphere/surface exchange of gases over an urban area are a direct way to improve and evaluate emissions inventories, and, in turn, to better understand urban atmospheric ...

Velasco, Erik

287

Characterization of niobium, tantalum and chromium sputtered coatings on steel using eddy currents  

E-Print Network [OSTI]

Characterization of niobium, tantalum and chromium sputtered coatings on steel using eddy currents for characterization of niobium, tantalum and chromium sputtered coating on steel is presented in this paper

Danon, Yaron

288

Microsoft Word - CX-Big Eddy-Redmond-WoodPolesFY13_WEB.doc  

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

4, 2013 REPLY TO ATTN OF: KEPR-4 SUBJECT: Environmental Clearance Memorandum Richard Heredia Project Manager - TEP-TPP-1 Proposed Action: Big Eddy-Redmond No. 1 Wood Pole...

289

Evidence for Enhanced Eddy Mixing at Middepth in the Southern Ocean K. SHAFER SMITH  

E-Print Network [OSTI]

Evidence for Enhanced Eddy Mixing at Middepth in the Southern Ocean K. SHAFER SMITH Center; Robinson and McWilliams 1974; Stammer 1997; Smith 2007), extracting their energy from the stores

Marshall, John

290

Quantum Simulation  

E-Print Network [OSTI]

Simulating quantum mechanics is known to be a difficult computational problem, especially when dealing with large systems. However, this difficulty may be overcome by using some controllable quantum system to study another less controllable or accessible quantum system, i.e., quantum simulation. Quantum simulation promises to have applications in the study of many problems in, e.g., condensed-matter physics, high-energy physics, atomic physics, quantum chemistry and cosmology. Quantum simulation could be implemented using quantum computers, but also with simpler, analog devices that would require less control, and therefore, would be easier to construct. A number of quantum systems such as neutral atoms, ions, polar molecules, electrons in semiconductors, superconducting circuits, nuclear spins and photons have been proposed as quantum simulators. This review outlines the main theoretical and experimental aspects of quantum simulation and emphasizes some of the challenges and promises of this fast-growing field.

I. M. Georgescu; S. Ashhab; Franco Nori

2014-03-13T23:59:59.000Z

291

Eddy current inspection of power plant heat-exchanger tubing in the USA  

SciTech Connect (OSTI)

The latest experience in the eddy current inspection of heat-exchanger tubing by means of ID probes is reported and generalized. The authors demonstrate the feasibility of using modern, general-purpose, digital eddy current flaw detectors equipped with microprocessors, displays, the capability for recording inspection results on paper or magnetic media, sound and visual alarms. The NDE personnel qualification and certification requirements are described.

Fishkin, P.; Nash, J. [MQS Inspection, Inc., Chicago, IL (United States)

1995-02-01T23:59:59.000Z

292

Variable current speed controller for eddy current motors  

DOE Patents [OSTI]

A speed control system for eddy current motors is provided in which the current to the motor from a constant frequency power source is varied by comparing the actual motor speed signal with a setpoint speed signal to control the motor speed according to the selected setpoint speed. A three-phase variable voltage autotransformer is provided for controlling the voltage from a three-phase power supply. A corresponding plurality of current control resistors is provided in series with each phase of the autotransformer output connected to inputs of a three-phase motor. Each resistor is connected in parallel with a set of normally closed contacts of plurality of relays which are operated by control logic. A logic circuit compares the selected speed with the actual motor speed obtained from a digital tachometer monitoring the motor spindle speed and operated the relays to add or substract resistance equally in each phase of the motor input to vary the motor current to control the motor at the selected speed.

Gerth, H.L.; Bailey, J.M.; Casstevens, J.M.; Dixon, J.H.; Griffith, B.O.; Igou, R.E.

1982-03-12T23:59:59.000Z

293

June 6, 2007 Large-Scale Scientific Computations'07, Sozopol, Bulgaria -p. 1/29 Multiscale Modeling and Simulation of Fluid  

E-Print Network [OSTI]

in porous media (soil, porous rocks, etc.) x Elasticity problems in composite materials (adobe, concrete/29 Presentation outline s Brief overview of upscaling methods in deformable porous media s The Fluid upscaling of flow in deformable porous media #12;June 6, 2007 Large-Scale Scientific Computations'07

Popov, Peter

294

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

SciTech Connect (OSTI)

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

295

Method and infrastructure for cycle-reproducible simulation on large scale digital circuits on a coordinated set of field-programmable gate arrays (FPGAs)  

DOE Patents [OSTI]

A plurality of target field programmable gate arrays are interconnected in accordance with a connection topology and map portions of a target system. A control module is coupled to the plurality of target field programmable gate arrays. A balanced clock distribution network is configured to distribute a reference clock signal, and a balanced reset distribution network is coupled to the control module and configured to distribute a reset signal to the plurality of target field programmable gate arrays. The control module and the balanced reset distribution network are cooperatively configured to initiate and control a simulation of the target system with the plurality of target field programmable gate arrays. A plurality of local clock control state machines reside in the target field programmable gate arrays. The local clock state machines are configured to generate a set of synchronized free-running and stoppable clocks to maintain cycle-accurate and cycle-reproducible execution of the simulation of the target system. A method is also provided.

Asaad, Sameh W; Bellofatto, Ralph E; Brezzo, Bernard; Haymes, Charles L; Kapur, Mohit; Parker, Benjamin D; Roewer, Thomas; Tierno, Jose A

2014-01-28T23:59:59.000Z

296

Eddy-resolving Lidar Measurements and Numerical Simulations of the Convective Internal Boundary Layer  

E-Print Network [OSTI]

in speed. The vertical gradient of wind-speed decreases offshore because of strong vertical mixing caused correlation functions and winds derived from horizontal (PPI) and vertical (RHI) scans of the VIL during Lake.4 0.5 0.6 0.7 DOWNSTREAM WIND SPEEDS FROM RHI SCANS ON 13 JANUARY 1998 SPATIALLY RESOLVED 5-m WINDS

Eloranta, Edwin W.

297

Adaptive Detached Eddy Simulation of a High Lift Wing with Active Flow  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc Documentation RUCProductstwrmrAre the EffectsAcknowledgmentdynamics in TrichodermaScovelControl

298

Magnetic diagnostics for equilibrium reconstructions with eddy currents on the lithium tokamak experiment  

SciTech Connect (OSTI)

The Lithium Tokamak eXperiment is a spherical tokamak with a close-fitting low-recycling wall composed of thin lithium layers evaporated onto a stainless steel-lined copper shell. Long-lived non-axisymmetric eddy currents are induced in the shell and vacuum vessel by transient plasma and coil currents and these eddy currents influence both the plasma and the magnetic diagnostic signals that are used as constraints for equilibrium reconstruction. A newly installed set of re-entrant magnetic diagnostics and internal saddle flux loops, compatible with high-temperatures and lithium environments, is discussed. Details of the axisymmetric (2D) and non-axisymmetric (3D) treatments of the eddy currents and the equilibrium reconstruction are presented.

Schmitt, J. C., E-mail: jschmitt@pppl.gov; Lazerson, S.; Majeski, R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Bialek, J. [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States)

2014-11-15T23:59:59.000Z

299

On The Use of Eddy Current Brakes as Tunable, Fast Turn-On Viscous Dampers For Haptic Rendering  

E-Print Network [OSTI]

On The Use of Eddy Current Brakes as Tunable, Fast Turn-On Viscous Dampers For Haptic Rendering, linear dampers for haptic rendering using a prototype haptic device outfitted with eddy current brakes discuss the results from haptic experiments for rendering viscosity, virtual walls and virtual friction

Hayward, Vincent

300

Two-Layer Baroclinic Eddy Heat Fluxes: Zonal Flows and Energy Balance ANDREW F. THOMPSON AND WILLIAM R. YOUNG  

E-Print Network [OSTI]

Two-Layer Baroclinic Eddy Heat Fluxes: Zonal Flows and Energy Balance ANDREW F. THOMPSON of these drag- less heat-flux parameterizations relies on the ability of to direct energy into zonal flows, California (Manuscript received 27 September 2006, in final form 13 December 2006) ABSTRACT The eddy heat

Young, William R.

Note: This page contains sample records for the topic "large eddy simulation" 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

Thorotrast and in vivo thorium dioxide: numerical simulation of 30 years of alpha radiation absorption by the tissues near a large compact source  

E-Print Network [OSTI]

Background: The epidemiology of the slightly radioactive contrast agent named Thorotrast presents a very long latency period between the injection and the development of the related pathologies. It is an example of the more general problem posed by a radioactive internal contaminant whose effects are not noteworthy in the short term but become dramatic in the long period. A point that is still to be explored is fluctuations (in space and time) in the localized absorption of radiation by the tissues. Methods: A Monte Carlo simulation code has been developed to study over a 30 year period the daily absorption of alpha radiation by micrometer sized portions of tissue placed at a distance of 0-100 micrometers from a model source, that approximates a compact thorium dioxide source in liver or spleen whose size is larger or equal to 20 micrometers. The biological depletion of the daughter nuclei of the thorium series is taken into account. The initial condition assumes chemically purified natural thorium. Results: ...

Bianconi, Andrea

2014-01-01T23:59:59.000Z

302

Transient Eddy Current Response Due to a Subsurface Crack in a Conductive Plate  

SciTech Connect (OSTI)

Eddy current nondestructive evaluation (NDE) is usually carried out by exciting a time harmonic field using an inductive probe. However, a viable alternative is to use transient eddy current NDE in which a current pulse in a driver coil produces a transient .eld in a conductor that decays at a rate dependent on the conductivity and the permeability of the material and the coil configuration. By using transient eddy current, it is possible to estimate the properties of the conductive medium and to locate and size potential .aws from the measured probe response. The fundamental study described in this dissertation seeks to establish a theoretical understanding of the transient eddy current NDE. Compared with the Fourier transform method, the derived analytical formulations are more convenient when the transient eddy current response within a narrow time range is evaluated. The theoretical analysis provides a valuable tool to study the effect of layer thickness, location of defect, crack opening as well as the optimization of probe design. Analytical expressions have been developed to evaluate the transient response due to eddy currents in a conductive plate based on two asymptotic series. One series converges rapidly for a short time regime and the other for a long time regime and both of them agree with the results calculated by fast Fourier transform over all the times considered. The idea of asymptotic expansion is further applied to determine the induced electromotive force (EMF) in a pick-up coil due to eddy currents in a cylindrical rod. Starting from frequency domain representation, a quasi-static time domain dyadic Green's function for an electric source in a conductive plate has been derived. The resulting expression has three parts; a free space term, multiple image terms and partial reflection terms. The dyadic Green's function serves as the kernel of an electric field integral equation which defines the interaction of an ideal crack with the transient eddy currents in a conductive plate. The crack response is found using the reciprocity theorem. Good agreement is observed between the predictions of the magnetic field due to the crack and experimental measurements.

Fangwei Fu

2006-08-09T23:59:59.000Z

303

Automated measurement system employing eddy currents to adjust probe position and determine metal hardness  

DOE Patents [OSTI]

A system for measuring the hardness of cartridge cases employs an eddy current probe for inducing and sensing eddy currents in each cartridge case. A first component of the sensed signal is utilized in a closed loop system for accurately positioning the probe relative to the cartridge case both in the lift off direction and in the tangential direction, and a second component of the sensed signal is employed as a measure of the hardness. The positioning and measurement are carried out under closed loop microprocessor control facilitating hardness testing on a production line basis. 14 figs.

Prince, J.M.; Dodson, M.G.; Lechelt, W.M.

1989-07-18T23:59:59.000Z

304

Evaporation characteristics of wetlands:experience from a wet grassland and a reedbed using eddy correlation measurements Hydrology and Earth System Sciences, 7(1), 1121 (2003) EGU  

E-Print Network [OSTI]

Evaporation characteristics of wetlands:experience from a wet grassland and a reedbed using eddy characteristics of wetlands: experience from a wet grassland and a reedbed using eddy correlation measurements M July to November 1999 using the eddy correlation method on two wetland types ­ wet grassland

Paris-Sud XI, Université de

305

A Greenland Sea Perspective on the Dynamics of Postconvective Eddies* K. I. C. OLIVER  

E-Print Network [OSTI]

A Greenland Sea Perspective on the Dynamics of Postconvective Eddies* K. I. C. OLIVER School and 2) to provide a theoretical context for recent observations of SCVs in the Greenland Sea hundred days. These findings may explain the observed accumulation and longevity of SCVs at the Greenland

Stevens, David

306

Monsoon surges trigger oceanic eddy formation and propagation in the lee of the Philippine Islands  

E-Print Network [OSTI]

wind jets and wakes in the lee of Mindoro and Luzon Islands induce the generation and migration of the winds with the topography of the islands creates strong curl patterns that spin-up a field of cyclonic to the orientation of the winds during each of the surges. Features shared by the eddies include size (100­ 200 km

307

Isentropic Slopes, Downgradient Eddy Fluxes, and the Extratropical Atmospheric Circulation Response to Tropical Tropospheric Heating  

E-Print Network [OSTI]

to Tropical Tropospheric Heating AMY H. BUTLER NOAA/NWS/NCEP/Climate Prediction Center, Camp Springs, Maryland of the midlatitude jets and their associated eddy fluxes of heat and potential vorticity (PV). Experiments run latent heating and thus locally enhanced warming in the tropical troposphere. Here the authors provide

308

Divergent Eddy Heat Fluxes in the Kuroshio Extension at 14481488E. Part I: Mean Structure  

E-Print Network [OSTI]

and the upper-ocean thermal front. EHFs associated with the internal mode are completely rotational. DEHFs were resulted in a mean-to-eddy potential energy conversion rate that peaked midthermocline with a magnitude and a nearly depth-independent external mode measured in the deep ocean. As a useful by

Rhode Island, University of

309

Multiple Hypothesis Object Tracking For Unsupervised Self-Learning: An Ocean Eddy Tracking Application  

E-Print Network [OSTI]

, and others 2003; Hoegh-Guldberg and Bruno 2010). In order to project a future response accurately eddies transport heat, salt, energy, and nutrients across oceans. As a result, accurately identi- fying and atmospheric CO2 levels remains a topic of intense scientific and societal inter- est (Caldeira, Wickett

Minnesota, University of

310

Examining strategies to improve the carbon balance of corn/soybean agriculture using eddy covariance and  

E-Print Network [OSTI]

if it occurs rapidly. Consequently, there is intense interest in finding ways to damp projected changesExamining strategies to improve the carbon balance of corn/soybean agriculture using eddy There is much interest in the role that agricultural practices might play in sequestering carbon to help offset

Minnesota, University of

311

The Santa Cruz Eddy. Part II: Mechanisms of Formation CRISTINA L. ARCHER AND MARK Z. JACOBSON  

E-Print Network [OSTI]

greater vorticity, wind speed, horizontal and vertical extents, and lifetime than the second eddy thermal gradients at ground level. In all cases, vertical vorticity was still created by the tilting," with horizontal resolution of 5 km, 150 120 grid points, 29 vertical levels, and 15-s time step), which covers

312

Stationary formulas for computing the response in eddy-current NDE  

SciTech Connect (OSTI)

Stationary or variational formulations have been proven to be useful in a number of electromagnetic problems. This paper presents such a formulation for the response in the eddy-current NDE problem. It thus provides an approach to estimating the response due to arbitrary defects in cases where a reasonable first guess for the current distribution responsible for the scattered fields can be obtained.

Hower, G.L.

1987-12-01T23:59:59.000Z

313

Eddy-mixed layer interactions in the ocean Raffaele Ferrari 1  

E-Print Network [OSTI]

Eddy-mixed layer interactions in the ocean Raffaele Ferrari 1 Massachusetts Institute of Technology and oceanic general circulation models do not reflect recent advances in our understanding the mesoscale variability (ocean cyclones and anticyclones) and microscale variability (turbu- lent mixing due

Ferrari, Raffaele

314

FRP Dowels for Concrete Pavements Darren Eddie, Junior Structural Engineer, Reid Crowther & Partners;  

E-Print Network [OSTI]

testing ofGFRP and steel dowels using a model of a concrete pavement slab joint subjected to static= L FRP Dowels for Concrete Pavements By Darren Eddie, Junior Structural Engineer, Reid Crowther - Introduction Joints are used in concrete pavements in order to control cracking due to thermal

315

Enabling Advanced Modeling and Simulations for Fuel-Flexible Combustors  

SciTech Connect (OSTI)

The overall goal of the present project is to enable advanced modeling and simulations for the design and optimization of fuel-flexible turbine combustors. For this purpose we use a high fidelity, extensively-tested large-eddy simulation (LES) code and state-of-the-art models for premixed/partially-premixed turbulent combustion developed in the PI's group. In the frame of the present project, these techniques are applied, assessed, and improved for hydrogen enriched premixed and partially premixed gas-turbine combustion. Our innovative approaches include a completely consistent description of flame propagation; a coupled progress variable/level set method to resolve the detailed flame structure, and incorporation of thermal-diffusion (non-unity Lewis number) effects. In addition, we have developed a general flamelet-type transformation holding in the limits of both non-premixed and premixed burning. As a result, a model for partially premixed combustion has been derived. The coupled progress variable/level method and the general flamelet transformation were validated by LES of a lean-premixed low-swirl burner that has been studied experimentally at Lawrence Berkeley National Laboratory. The model is extended to include the non-unity Lewis number effects, which play a critical role in fuel-flexible combustor with high hydrogen content fuel. More specifically, a two-scalar model for lean hydrogen and hydrogen-enriched combustion is developed and validated against experimental and direct numerical simulation (DNS) data. Results are presented to emphasize the importance of non-unity Lewis number effects in the lean-premixed low-swirl burner of interest in this project. The proposed model gives improved results, which shows that the inclusion of the non-unity Lewis number effects is essential for accurate prediction of the lean-premixed low-swirl flame.

Pitsch, Heinz

2010-05-31T23:59:59.000Z

316

Localized dynamic subgrid closure for simulation of magnetohydrodynamic turbulence  

SciTech Connect (OSTI)

A local dynamic kinetic energy model (LDKM) for large-eddy simulation (LES) of magnetohydrodynamic (MHD) turbulence is proposed. The proposed MHD turbulence model evaluates all model coefficients locally and dynamically without any ad hoc averaging. This model also does not assume low magnetic Reynolds numbers. The turbulent residual-helicity effect ({alpha}-effect) appearing in the magnetic induction equation is successfully modeled. For validation, high-Re decaying isotropic decay turbulence with and without a mean magnetic field are studied using LES. The effect of rotation is also studied. For the case without rotation, it is observed that the energy spectrum follows a k{sup -5/3} law. For the case with rotation, it is shown that two mechanisms, phase scrambling due to frame rotation and Joule dissipation, are competing, and two distinct regimes with respect to rotation rate are observed. There is a critical rotation rate at which the energy decays most in MHD turbulence. It is also shown that this MHD-LDKM model is applicable to wide variety of high/low magnetic Reynolds number applications.

Miki, Kenji; Menon, Suresh [Georgia Institute of Technology, School of Aerospace Engineering, Atlanta, Georgia 30332-0150 (United States)

2008-07-15T23:59:59.000Z

317

Analysis of azimuthal mode dynamics of mesoscale eddies  

E-Print Network [OSTI]

Rossby wave modes. The results appear to be in excellent qualitative agree- ment with Fli erl's (1977) analytic solutions. But the real advantage to numerical simulation is in the application to nonlinear models and arbitrary initial conditions. Mc...Wi lli ams and Fli erl ( 1979) presented the results of an extensive parameter survey using their two-mode non- linear quasigeostrophic model. The primary result is that nonlinear processes impede dispersion in intense vortices, so that friction be...

McCalpin, John David

1984-01-01T23:59:59.000Z

318

Large-scale gyrokinetic particle simulation of  

E-Print Network [OSTI]

form for private use is permitted without payment of royalty provided that (1) each reproduction or distributed royalty free without further permission by computer-based and other information-service systems

Oliker, Leonid

319

Volunteer Computing and Large-Scale Simulation  

E-Print Network [OSTI]

privately owned) ! Early projects (1996-1999) ­ GIMPS ­ distributed.net ­ SETI@home ­ Folding@home

Taufer, Michela

320

3D direct and inverse solvers for eddy current testing of deposits in steam generator  

E-Print Network [OSTI]

We consider the inverse problem of estimating the shape profile of an unknown deposit from a set of eddy current impedance measurements. The measurements are acquired with an axial probe, which is modeled by a set of coils that generate a magnetic field inside the tube. For the direct problem, we validate the method that takes into account the tube support plates, highly conductive part, by a surface impedance condition. For the inverse problem, finite element and shape sensitivity analysis related to the eddy current problem are provided in order to determine the explicit formula of the gradient of a least square misfit functional. A geometrical-parametric shape inversion algorithm based on cylindrical coordinates is designed to improve the robustness and the quality of the reconstruction. Several numerical results are given in the experimental part. Numerical experiments on synthetic deposits, nearby or far away from the tube, with different shapes are considered in the axisymmetric configuration.

Haddar, Houssem

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "large eddy simulation" 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

Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers  

DOE Patents [OSTI]

A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations in the particle beam.

Danby, Gordon T. (Wading River, NY); Jackson, John W. (Shoreham, NY)

1991-01-01T23:59:59.000Z

322

Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers  

DOE Patents [OSTI]

A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations (dB/dt) in the particle beam.

Danby, G.T.; Jackson, J.W.

1990-03-19T23:59:59.000Z

323

Simulating neural systems with Xyce.  

SciTech Connect (OSTI)

Sandia's parallel circuit simulator, Xyce, can address large scale neuron simulations in a new way extending the range within which one can perform high-fidelity, multi-compartment neuron simulations. This report documents the implementation of neuron devices in Xyce, their use in simulation and analysis of neuron systems.

Schiek, Richard Louis; Thornquist, Heidi K.; Mei, Ting; Warrender, Christina E.; Aimone, James Bradley; Teeter, Corinne; Duda, Alex M. [University of Illinois, Urbana-Champaign

2012-12-01T23:59:59.000Z

324

The Local Variational Multiscale Method for Turbulence Simulation.  

SciTech Connect (OSTI)

Accurate and efficient turbulence simulation in complex geometries is a formidable chal-lenge. Traditional methods are often limited by low accuracy and/or restrictions to simplegeometries. We explore the merger of Discontinuous Galerkin (DG) spatial discretizationswith Variational Multi-Scale (VMS) modeling, termed Local VMS (LVMS), to overcomethese limitations. DG spatial discretizations support arbitrarily high-order accuracy on un-structured grids amenable for complex geometries. Furthermore, high-order, hierarchicalrepresentation within DG provides a natural framework fora prioriscale separation crucialfor VMS implementation. We show that the combined benefits of DG and VMS within theLVMS method leads to promising new approach to LES for use in complex geometries.The efficacy of LVMS for turbulence simulation is assessed by application to fully-developed turbulent channelflow. First, a detailed spatial resolution study is undertakento record the effects of the DG discretization on turbulence statistics. Here, the localhp[?]refinement capabilites of DG are exploited to obtain reliable low-order statistics effi-ciently. Likewise, resolution guidelines for simulating wall-bounded turbulence using DGare established. We also explore the influence of enforcing Dirichlet boundary conditionsindirectly through numericalfluxes in DG which allows the solution to jump (slip) at thechannel walls. These jumps are effective in simulating the influence of the wall commen-surate with the local resolution and this feature of DG is effective in mitigating near-wallresolution requirements. In particular, we show that by locally modifying the numericalviscousflux used at the wall, we are able to regulate the near-wall slip through a penaltythat leads to improved shear-stress predictions. This work, demonstrates the potential ofthe numerical viscousflux to act as a numerically consistent wall-model and this successwarrents future research.As in any high-order numerical method some mechanism is required to control aliasingeffects due to nonlinear interactions and to ensure nonlinear stability of the method. Inthis context, we evaluate the merits of two approaches to de-aliasing -- spectralfilteringand polynomial dealiasing. While both approaches are successful, polynomial-dealiasingis found to be better suited for use in large-eddy simulation. Finally, results using LVMSare reported and show good agreement with reference direct numerical simulation therebydemonstrating the effectiveness of LVMS for wall-bounded turbulence. This success pavesthe way for future applications of LVMS to more complex turbulentflows.3

Collis, Samuel Scott; Ramakrishnan, Srinivas

2005-05-01T23:59:59.000Z

325

Role of mesoscale eddies in transport of Fukushima-derived cesium isotopes in the ocean  

E-Print Network [OSTI]

We present the results of in-situ measurements of $^{134}$Cs and $^{137}$Cs released from the Fukushima Nuclear Power Plant (FNPP) collected at surface and different depths in the western North Pacific in June and July 2012. It was found that 15 month after the incident concentrations of radiocesium in the Japan and Okhotsk seas were at background or slightly increased level, while they had increased values in the subarctic front area east of Japan. The highest concentrations of $^{134}$Cs and $^{137}$Cs up to 13.5 ${\\pm}$ 0.9 and 22.7 ${\\pm}$ 1.5 Bq m$^{-3}$ have been found to exceed ten times the background levels before the accident. Maximal content of radiocesium was observed within subsurface and intermediate water layers inside the cores of anticyclonic eddies (100 - 500 m). Even slightly increased content of radiocesium was found at some eddies at depth of 1000 m. It is expected that convergence and subduction of surface water inside eddies are main mechanisms of downward transport of radionuclides. In...

Budyansky, M V; Kaplunenko, D D; Lobanov, V B; Prants, S V; Sergeev, A F; Shlyk, N V; Uleysky, M Yu

2014-01-01T23:59:59.000Z

326

Deep-Sea Research II 53 (2006) 29562984 Numerical model simulations of continental shelf flows off  

E-Print Network [OSTI]

structure that appears just north of Bodega Bay and shows the offshore jet strengthening to the south. We with realistic topography and initial stratification in a limited-area domain with a high-resolution grid eddy-like recirculation feature offshore of Pt. Arena prior to the upwelling event causes large patches

Pierce, Stephen

327

A nested grid model of the Oregon Coastal Transition Zone: Simulations and comparisons with observations during the 2001  

E-Print Network [OSTI]

A nested grid model of the Oregon Coastal Transition Zone: Simulations and comparisons several hundred kilometers offshore where shelf flows interact with the northern California Current is realistic representation of coastal jet separation and eddy formation offshore of Cape Blanco. Three

Kurapov, Alexander

328

Ship and satellite observations of chlorophyl stocks in interacting cyclone-anticyclone eddy pairs in the western Gulf of Mexico  

SciTech Connect (OSTI)

When anticyclonic eddies shed by the Loop Current of the Gulf of Mexico reach the western margin of the gulf, they influence the surface circulation over the continental slope and rise. Of particular interest is the generation of cyclone (cold-core)- anticyclone (warm-core) pairs when aging Loop Current eddies interact with the continental margin. In this paper the authors describe the physical and biological characteristics of these cyclone-anticyclone pairs. Their objective was to determine how eddy pairs affect the distribution of phytoplankton in the region and how satellite ocean color measurements are applicable to tracing of the eddies. They present shipboard data collected between 1980 and 1982 on the hydrography, chlorophyll stocks, and nutrient concentrations of eddy pairs in the western Gulf of Mexico and compare these data with coastal zone color scanner (CZCS) images collected during the time frame of the cruises. Surface pigment concentrations followed a seasonal cycle, with low concentrations (0.05-0.1 mg m{sup {minus}3}) found within cyclones and anticyclones from April through early November and higher concentrations (>0.1 mg m{sup {minus}3}) found in the winter. CZCS pigment concentrations were locally high in the flow confluence of cyclone-anticyclone pairs. The CZCS imagery shows that some cyclone-anticyclone geometries transport high-chlorophyll shelf water seaward at least 100-200 km off-shelf. 46 figs., 9 figs., 3 tabs.

Biggs, D.C. [Texas A& M Univ., College Station, TX (United States)] [Texas A& M Univ., College Station, TX (United States); Mueller-Karger, F.E. [Univ. of South Florida, St. Petersburg, FL (United States)] [Univ. of South Florida, St. Petersburg, FL (United States)

1994-04-15T23:59:59.000Z

329

Crack detection on HC-130H aircraft using low frequency eddy current  

SciTech Connect (OSTI)

An eddy current inspection method was developed at the Federal Aviation Administration`s Airworthiness Assurance NDI Validation Center (AANC) to easily and rapidly detect subsurface fatigue cracks in the wheel well fairing on the US Coast Guard (USCG) HC-130H aircraft caused by fatigue. The inspection procedure locates cracks as small as 10.2 millimeters in length at 2.54 mm below the skin surface at raised fastener sites. The test procedure developed baseline three USCG aircraft. Inspection results on the three aircraft reveals good correlation with results made during subsequent structural disassembly.

Moore, D.G. [Sandia National Labs., Albuquerque, NM (United States); Mihelic, J.E.; Barnes, J.D. [Coast Guard, Elizabeth City, NC (United States). Aircraft Repair and Supply Center

1998-02-01T23:59:59.000Z

330

GEOPHYSICAL RESEARCH LETTERS, VOL. 40, 16, doi:10.1002/2013GL057728, 2013 Up-gradient eddy fluxes of potential vorticity near the subtropical jet  

E-Print Network [OSTI]

GEOPHYSICAL RESEARCH LETTERS, VOL. 40, 1­6, doi:10.1002/2013GL057728, 2013 Up-gradient eddy fluxes the subtropical jet, Geophys. Res. Lett., 40, doi:10.1002/2013GL057728. 1. Eddies and the General Circulation [2 Geophysical Union. All Rights Reserved. 0094-8276/13/10.1002/2013GL057728 scales are small compared

Birner, Thomas

331

GEOPHYSICAL RESEARCH LETTERS, VOL. 40, 59885993, doi:10.1002/2013GL057728, 2013 Up-gradient eddy fluxes of potential vorticity near the subtropical jet  

E-Print Network [OSTI]

GEOPHYSICAL RESEARCH LETTERS, VOL. 40, 5988­5993, doi:10.1002/2013GL057728, 2013 Up-gradient eddy near the subtropical jet, Geophys. Res. Lett., 40, 5988­5993, doi:10.1002/2013GL057728. 1. Eddies@atmos.colostate.edu) ©2013. American Geophysical Union. All Rights Reserved. 0094-8276/13/10.1002/2013GL057728 scales

332

Satellite Observations of Mesoscale Eddy-Induced Ekman Pumping1 Peter Gaube ,Dudley B. Chelton, Roger M. Samelson, Michael G. Schlax, Larry W. O'Neill2  

E-Print Network [OSTI]

Satellite Observations of Mesoscale Eddy-Induced Ekman Pumping1 Peter Gaube ,Dudley B. Chelton;Three mechanisms for self-induced Ekman pumping in the interiors of mesoscale ocean eddies temperature (SST) field, which generates a stress curl and therefore Ekman pumping in regions of crosswind SST

333

Satellite Observations of Mesoscale Eddy-Induced Ekman Pumping1 Peter Gaube ,Dudley B. Chelton, Roger M. Samelson, Michael G. Schlax, Larry W. O'Neill2  

E-Print Network [OSTI]

Satellite Observations of Mesoscale Eddy-Induced Ekman Pumping1 Peter Gaube ,Dudley B. Chelton;Three mechanisms for self-induced Ekman pumping in the interiors of mesoscale ocean eddies generates a curl of the stress and therefore Ekman pumping in regions of crosswind SST gradients

Samelson, Roger

334

SciTech Connect: Comparison of the Dynamic Wake Meandering Model...  

Office of Scientific and Technical Information (OSTI)

Technologies Office Country of Publication: United States Language: English Subject: 17 WIND ENERGY WIND PLANT AERODYNAMICS; DYNAMIC WAKE MEANDERING; LARGE-EDDY SIMULATION; Wind...

335

An analytical demonstration of coupling schemes between magnetohydrodynamic codes and eddy current codes  

SciTech Connect (OSTI)

In order to model a magnetohydrodynamic (MHD) instability that strongly couples to external conducting structures (walls and/or coils) in a fusion device, it is often necessary to combine a MHD code solving for the plasma response, with an eddy current code computing the fields and currents of conductors. We present a rigorous proof of the coupling schemes between these two types of codes. One of the coupling schemes has been introduced and implemented in the CARMA code [R. Albanese, Y. Q. Liu, A. Portone, G. Rubinacci, and F. Villone, IEEE Trans. Magn. 44, 1654 (2008); A. Portone, F. Villone, Y. Q. Liu, R. Albanese, and G. Rubinacci, Plasma Phys. Controlled Fusion 50, 085004 (2008)] that couples the MHD code MARS-F[Y. Q. Liu, A. Bondeson, C. M. Fransson, B. Lennartson, and C. Breitholtz, Phys. Plasmas 7, 3681 (2000)] and the eddy current code CARIDDI[R. Albanese and G. Rubinacci, Adv. Imaging Electron Phys. 102, 1 (1998)]. While the coupling schemes are described for a general toroidal geometry, we give the analytical proof for a cylindrical plasma.

Liu Yueqiang [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Albanese, R.; Rubinacci, G. [ENEA/CREATE, Universita Federico II di Napoli, Via Claudio 21, Napoli (Italy); Portone, A. [EFDA-CSU Barcelona, C/Josep Pla 2, B3, 08019 Barcelona (Spain); Villone, F. [ENEA/CREATE, DAEIMI, Universita di Cassino, Via di Biasio 43, Cassino (Italy)

2008-07-15T23:59:59.000Z

336

IFP Energies nouvelles International Conference Rencontres Scientifiques d'IFP Energies nouvelles  

E-Print Network [OSTI]

Large Eddy Simulations Applied to Non-Reactive Transient Diesel Sprays Anthony Robert, Lionel Martinez Euler ­ Euler pour la simulation aux grandes e´ chelles de sprays Diesel instationnaires non-re´ actifs (LES, Large Eddy Simulations) de sprays Diesel instationnaires dans une cellule haute pression et haute

Boyer, Edmond

337

IFP Energies nouvelles International Conference Rencontres Scientifiques d'IFP Energies nouvelles  

E-Print Network [OSTI]

LES4ICE 2012 - Large Eddy Simulation for Internal Combustion Engine Flows LES4ICE 2012 - La simulation engine combustion is critical to improve engine efficiency while reducing pol- lutant emissions. To study aux grandes échelles pour les écoulements dans les moteurs à combustion interne Large-Eddy Simulation

Paris-Sud XI, Université de

338

Bluff Body Flow Simulation Using a Vortex Element Method  

SciTech Connect (OSTI)

Heavy ground vehicles, especially those involved in long-haul freight transportation, consume a significant part of our nation's energy supply. it is therefore of utmost importance to improve their efficiency, both to reduce emissions and to decrease reliance on imported oil. At highway speeds, more than half of the power consumed by a typical semi truck goes into overcoming aerodynamic drag, a fraction which increases with speed and crosswind. Thanks to better tools and increased awareness, recent years have seen substantial aerodynamic improvements by the truck industry, such as tractor/trailer height matching, radiator area reduction, and swept fairings. However, there remains substantial room for improvement as understanding of turbulent fluid dynamics grows. The group's research effort focused on vortex particle methods, a novel approach for computational fluid dynamics (CFD). Where common CFD methods solve or model the Navier-Stokes equations on a grid which stretches from the truck surface outward, vortex particle methods solve the vorticity equation on a Lagrangian basis of smooth particles and do not require a grid. They worked to advance the state of the art in vortex particle methods, improving their ability to handle the complicated, high Reynolds number flow around heavy vehicles. Specific challenges that they have addressed include finding strategies to accurate capture vorticity generation and resultant forces at the truck wall, handling the aerodynamics of spinning bodies such as tires, application of the method to the GTS model, computation time reduction through improved integration methods, a closest point transform for particle method in complex geometrics, and work on large eddy simulation (LES) turbulence modeling.

Anthony Leonard; Phillippe Chatelain; Michael Rebel

2004-09-30T23:59:59.000Z

339

PUBLISHED ONLINE: 13 JULY 2014 | DOI: 10.1038/NGEO2200 Eddy-induced variability in Southern Ocean  

E-Print Network [OSTI]

of the world ocean upwell to the surface and subsequently sink to intermediate and abyssal depths, forming two overturning cells that exchange substantial quantities of heat and carbon with the atmosphere4, derived from moored current meter and altimetric measurements. As the intensity of the regional eddy field

Naveira Garabato, Alberto

340

Quantifying the eddy diffusivity of the Southern Ocean II: spatial variability and the role of the mean flow  

E-Print Network [OSTI]

average and the distinction between lo- cally generated complexity in the tracer structure and between of this eddy activity arises through baroclinic instability, although barotropic insta- bility, wind forcing and topographic interactions are also thought to play a role in some regions. In addition there is strong

Marshall, John

Note: This page contains sample records for the topic "large eddy simulation" 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

Influence of Droplet Geometry on the Coalescence of Low Viscosity Drops A. Eddi, K. G. Winkels, and J. H. Snoeijer  

E-Print Network [OSTI]

Influence of Droplet Geometry on the Coalescence of Low Viscosity Drops A. Eddi, K. G. Winkels involving sprays and print- ing [4,5]. Breakup and coalescence are singular events during which the liquid-off is universal in the sense that it is completely independent of initial conditions. In this regime, viscosity

Snoeijer, Jacco

342

Methane Emissions from a Small Wind Shielded Lake Determined by Eddy Covariance, Flux Chambers, Anchored Funnels, and Boundary  

E-Print Network [OSTI]

Methane Emissions from a Small Wind Shielded Lake Determined by Eddy Covariance, Flux Chambers of methane, held to be responsible for 18% of the radiative forcing, to the atmosphere. Periods of lake but potentially one of the most important periods for methane emissions. We studied methane emissions using four

Wehrli, Bernhard

343

Mountable eddy current sensor for in-situ remote detection of surface and sub-surface fatigue cracks  

DOE Patents [OSTI]

A wireless, integrated, mountable, portable, battery-operated, non-contact eddy current sensor that provides similar accuracy to 1970's laboratory scale equipment (e.g., a Hewlett-Packard GP4194A Impedance Analyzer) at a fraction of the size and cost.

Yepez, III, Esteban (Albuquerque, NM); Roach, Dennis P. (Albuquerque, NM); Rackow, Kirk A. (Albuquerque, NM); DeLong, Waylon A. (Albuquerque, NM)

2011-09-06T23:59:59.000Z

344

Simulations of Turbulent Flows with Strong Shocks and Density Variations: Final Report  

SciTech Connect (OSTI)

The target of this SciDAC Science Application was to develop a new capability based on high-order and high-resolution schemes to simulate shock-turbulence interactions and multi-material mixing in planar and spherical geometries, and to study Rayleigh-Taylor and Richtmyer-Meshkov turbulent mixing. These fundamental problems have direct application in high-speed engineering flows, such as inertial confinement fusion (ICF) capsule implosions and scramjet combustion, and also in the natural occurrence of supernovae explosions. Another component of this project was the development of subgrid-scale (SGS) models for large-eddy simulations of flows involving shock-turbulence interaction and multi-material mixing, that were to be validated with the DNS databases generated during the program. The numerical codes developed are designed for massively-parallel computer architectures, ensuring good scaling performance. Their algorithms were validated by means of a sequence of benchmark problems. The original multi-stage plan for this five-year project included the following milestones: 1) refinement of numerical algorithms for application to the shock-turbulence interaction problem and multi-material mixing (years 1-2); 2) direct numerical simulations (DNS) of canonical shock-turbulence interaction (years 2-3), targeted at improving our understanding of the physics behind the combined two phenomena and also at guiding the development of SGS models; 3) large-eddy simulations (LES) of shock-turbulence interaction (years 3-5), improving SGS models based on the DNS obtained in the previous phase; 4) DNS of planar/spherical RM multi-material mixing (years 3-5), also with the two-fold objective of gaining insight into the relevant physics of this instability and aiding in devising new modeling strategies for multi-material mixing; 5) LES of planar/spherical RM mixing (years 4-5), integrating the improved SGS and multi-material models developed in stages 3 and 5. This final report is outlined as follows. Section 2 shows an assessment of numerical algorithms that are best suited for the numerical simulation of compressible flows involving turbulence and shock phenomena. Sections 3 and 4 deal with the canonical shock-turbulence interaction problem, from the DNS and LES perspectives, respectively. Section 5 considers the shock-turbulence inter-action in spherical geometry, in particular, the interaction of a converging shock with isotropic turbulence as well as the problem of the blast wave. Section 6 describes the study of shock-accelerated mixing through planar and spherical Richtmyer-Meshkov mixing as well as the shock-curtain interaction problem In section 7 we acknowledge the different interactions between Stanford and other institutions participating in this SciDAC project, as well as several external collaborations made possible through it. Section 8 presents a list of publications and presentations that have been generated during the course of this SciDAC project. Finally, section 9 concludes this report with the list of personnel at Stanford University funded by this SciDAC project.

Sanjiva Lele

2012-10-01T23:59:59.000Z

345

EDDY RESOLVING NUTRIENT ECODYNAMICS IN THE GLOBAL PARALLEL OCEAN PROGRAM AND CONNECTIONS WITH TRACE GASES IN THE SULFUR, HALOGEN AND NMHC CYCLES  

SciTech Connect (OSTI)

Ecodynamics and the sea-air transfer of climate relevant trace gases are intimately coupled in the oceanic mixed layer. Ventilation of species such as dimethyl sulfide and methyl bromide constitutes a key linkage within the earth system. We are creating a research tool for the study of marine trace gas distributions by implementing coupled ecology-gas chemistry in the high resolution Parallel Ocean Program (POP). The fundamental circulation model is eddy resolving, with cell sizes averaging 0.15 degree (lat/long). Here we describe ecochemistry integration. Density dependent mortality and iron geochemistry have enhanced agreement with chlorophyll measurements. Indications are that dimethyl sulfide production rates must be adjusted for latitude dependence to match recent compilations. This may reflect the need for phytoplankton to conserve nitrogen by favoring sulfurous osmolytes. Global simulations are also available for carbonyl sulfide, the methyl halides and for nonmethane hydrocarbons. We discuss future applications including interaction with atmospheric chemistry models, high resolution biogeochemical snapshots and the study of open ocean fertilization.

S. CHU; S. ELLIOTT

2000-08-01T23:59:59.000Z

346

Advanced Oil Recovery Technologies for Improved Recovery from Slope Basin Clastic Reservoirs, Nash Draw Brushy Canyon Pool, Eddy County, NM  

SciTech Connect (OSTI)

The Nash Draw Brushy Canyon Pool in Eddy County New Mexico was a cost-shared field demonstration project in the U.S. Department of Energy Class III Program. A major goal of the Class III Program was to stimulate the use of advanced technologies to increase ultimate recovery from slope-basin clastic reservoirs. Advanced characterization techniques were used at the Nash Draw Pool (NDP) project to develop reservoir management strategies for optimizing oil recovery from this Delaware reservoir. The objective of the project was to demonstrate that a development program, which was based on advanced reservoir management methods, could significantly improve oil recovery at the NDP. Initial goals were (1) to demonstrate that an advanced development drilling and pressure maintenance program can significantly improve oil recovery compared to existing technology applications and (2) to transfer these advanced methodologies to other oil and gas producers. Analysis, interpretation, and integration of recently acquired geological, geophysical, and engineering data revealed that the initial reservoir characterization was too simplistic to capture the critical features of this complex formation. Contrary to the initial characterization, a new reservoir description evolved that provided sufficient detail regarding the complexity of the Brushy Canyon interval at Nash Draw. This new reservoir description was used as a risk reduction tool to identify 'sweet spots' for a development drilling program as well as to evaluate pressure maintenance strategies. The reservoir characterization, geological modeling, 3-D seismic interpretation, and simulation studies have provided a detailed model of the Brushy Canyon zones. This model was used to predict the success of different reservoir management scenarios and to aid in determining the most favorable combination of targeted drilling, pressure maintenance, well stimulation, and well spacing to improve recovery from this reservoir. An Advanced Log Analysis technique developed from the NDP project has proven useful in defining additional productive zones and refining completion techniques. This program proved to be especially helpful in locating and evaluating potential recompletion intervals, which has resulted in low development costs with only small incremental increases in lifting costs. To develop additional reserves at lower costs, zones behind pipe in existing wells were evaluated using techniques developed for the Brushy Canyon interval. These techniques were used to complete uphole zones in thirteen of the NDP wells. A total of 14 recompletions were done: four during 1999, four during 2000, two during 2001, and four during 2002-2003. These workovers added reserves of 332,304 barrels of oil (BO) and 640,363 MCFG (thousand cubic feet of gas) at an overall weighted average development cost of $1.87 per BOE (barrel of oil equivalent). A pressure maintenance pilot project in a developed area of the field was not conducted because the pilot area was pressure depleted, and the reservoir in that area was found to be compartmentalized and discontinuous. Economic analyses and simulation studies indicated that immiscible injection of lean hydrocarbon gas for pressure maintenance was not warranted at the NDP and would need to be considered for implementation in similar fields very soon after production has started. Simulation studies suggested that the injection of miscible carbon dioxide (CO{sub 2}) could recover significant quantities of oil at the NDP, but a source of low-cost CO{sub 2} was not available in the area. Results from the project indicated that further development will be under playa lakes and potash areas that were beyond the regions covered by well control and are not accessible with vertical wells. These areas, covered by 3-D seismic surveys that were obtained as part of the project, were accessed with combinations of deviated/horizontal wells. Three directional/horizontal wells have been drilled and completed to develop reserves under surface-restricted areas and potash mines. The third

Mark B. Murphy

2005-09-30T23:59:59.000Z

347

Bayesian Analysis for Large Spatial Data  

E-Print Network [OSTI]

simulations, so Bayesian approach is infeasible for large sample size n due to the current computational power limit. In this dissertation, we propose two approaches to address this computational issue, namely, the auxiliary lattice model (ALM) approach...

Park, Jincheol

2012-10-19T23:59:59.000Z

348

Computer simulation of neutron capture therapy.  

E-Print Network [OSTI]

Analytical methods are developed to simulate on a large digital computer the production and use of reactor neutron beams f or boron capture therapy of brain tumors. The simulation accounts for radiation dose distributions ...

Olson, Arne Peter

1967-01-01T23:59:59.000Z

349

Computer simulation of neutron capture therapy  

E-Print Network [OSTI]

Analytical methods are developed to simulate on a large digital computer the production and use of reactor neutron beams f or boron capture therapy of brain tumors. The simulation accounts for radiation dose distributions ...

Olson, Arne Peter

1967-01-01T23:59:59.000Z

350

Towards Grid-Wide Modeling and Simulation  

E-Print Network [OSTI]

Modeling and simulation permeate all areas of business, science and engineering. With the increase in the scale and complexity of simulations, large amounts of computational resources are required, and collaborative model ...

Xie, Yong

351

Adaptive LES Methodology for Turbulent Flow Simulations  

SciTech Connect (OSTI)

Although turbulent flows are common in the world around us, a solution to the fundamental equations that govern turbulence still eludes the scientific community. Turbulence has often been called one of the last unsolved problem in classical physics, yet it is clear that the need to accurately predict the effect of turbulent flows impacts virtually every field of science and engineering. As an example, a critical step in making modern computational tools useful in designing aircraft is to be able to accurately predict the lift, drag, and other aerodynamic characteristics in numerical simulations in a reasonable amount of time. Simulations that take months to years to complete are much less useful to the design cycle. Much work has been done toward this goal (Lee-Rausch et al. 2003, Jameson 2003) and as cost effective accurate tools for simulating turbulent flows evolve, we will all benefit from new scientific and engineering breakthroughs. The problem of simulating high Reynolds number (Re) turbulent flows of engineering and scientific interest would have been solved with the advent of Direct Numerical Simulation (DNS) techniques if unlimited computing power, memory, and time could be applied to each particular problem. Yet, given the current and near future computational resources that exist and a reasonable limit on the amount of time an engineer or scientist can wait for a result, the DNS technique will not be useful for more than 'unit' problems for the foreseeable future (Moin & Kim 1997, Jimenez & Moin 1991). The high computational cost for the DNS of three dimensional turbulent flows results from the fact that they have eddies of significant energy in a range of scales from the characteristic length scale of the flow all the way down to the Kolmogorov length scale. The actual cost of doing a three dimensional DNS scales as Re{sup 9/4} due to the large disparity in scales that need to be fully resolved. State-of-the-art DNS calculations of isotropic turbulence have recently been completed at the Japanese Earth Simulator (Yokokawa et al. 2002, Kaneda et al. 2003) using a resolution of 40963 (approximately 10{sup 11}) grid points with a Taylor-scale Reynolds number of 1217 (Re {approx} 10{sup 6}). Impressive as these calculations are, performed on one of the world's fastest super computers, more brute computational power would be needed to simulate the flow over the fuselage of a commercial aircraft at cruising speed. Such a calculation would require on the order of 10{sup 16} grid points and would have a Reynolds number in the range of 108. Such a calculation would take several thousand years to simulate one minute of flight time on today's fastest super computers (Moin & Kim 1997). Even using state-of-the-art zonal approaches, which allow DNS calculations that resolve the necessary range of scales within predefined 'zones' in the flow domain, this calculation would take far too long for the result to be of engineering interest when it is finally obtained. Since computing power, memory, and time are all scarce resources, the problem of simulating turbulent flows has become one of how to abstract or simplify the complexity of the physics represented in the full Navier-Stokes (NS) equations in such a way that the 'important' physics of the problem is captured at a lower cost. To do this, a portion of the modes of the turbulent flow field needs to be approximated by a low order model that is cheaper than the full NS calculation. This model can then be used along with a numerical simulation of the 'important' modes of the problem that cannot be well represented by the model. The decision of what part of the physics to model and what kind of model to use has to be based on what physical properties are considered 'important' for the problem. It should be noted that 'nothing is free', so any use of a low order model will by definition lose some information about the original flow.

Oleg V. Vasilyev

2008-06-12T23:59:59.000Z

352

Intercomparison of cloud model simulations of Arctic mixed-phase boundary layer clouds observed during SHEBA/FIRE-ACE  

SciTech Connect (OSTI)

An intercomparison of six cloud-resolving and large-eddy simulation models is presented. This case study is based on observations of a persistent mixed-phase boundary layer cloud gathered on 7 May, 1998 from the Surface Heat Budget of Arctic Ocean (SHEBA) and First ISCCP Regional Experiment - Arctic Cloud Experiment (FIRE-ACE). Ice nucleation is constrained in the simulations in a way that holds the ice crystal concentration approximately fixed, with two sets of sensitivity runs in addition to the baseline simulations utilizing different specified ice nucleus (IN) concentrations. All of the baseline and sensitivity simulations group into two distinct quasi-steady states associated with either persistent mixed-phase clouds or all-ice clouds after the first few hours of integration, implying the existence of multiple equilibria. These two states are associated with distinctly different microphysical, thermodynamic, and radiative characteristics. Most but not all of the models produce a persistent mixed-phase cloud qualitatively similar to observations using the baseline IN/crystal concentration, while small increases in the IN/crystal concentration generally lead to rapid glaciation and conversion to the all-ice state. Budget analysis indicates that larger ice deposition rates associated with increased IN/crystal concentrations have a limited direct impact on dissipation of liquid in these simulations. However, the impact of increased ice deposition is greatly enhanced by several interaction pathways that lead to an increased surface precipitation flux, weaker cloud top radiative cooling and cloud dynamics, and reduced vertical mixing, promoting rapid glaciation of the mixed-phase cloud for deposition rates in the cloud layer greater than about 1-2x10-5 g kg-1 s-1. These results indicate the critical importance of precipitation-radiative-dynamical interactions in simulating cloud phase, which have been neglected in previous fixed-dynamical parcel studies of the cloud phase parameter space. Large sensitivity to the IN/crystal concentration also suggests the need for improved understanding of ice nucleation and its parameterization in models.

Morrison, H.; Zuidema, Paquita; Ackerman, Andrew; Avramov, Alexander; de Boer, Gijs; Fan, Jiwen; Fridlind, Ann; Hashino, Tempei; Harrington, Jerry Y.; Luo, Yali; Ovchinnikov, Mikhail; Shipway, Ben

2011-06-16T23:59:59.000Z

353

Reservoir management using streamline simulation  

E-Print Network [OSTI]

of information and sparsity of data. Quantifying this uncertainty in terms of reservoir performance forecast poses a major reservoir management challenge. One solution to this problem is flow simulation of a large number of these plausible reservoir descriptions...

Choudhary, Manoj Kumar

2000-01-01T23:59:59.000Z

354

AIAA JOURNAL Vol. 44, No. 4, April 2006  

E-Print Network [OSTI]

AIAA JOURNAL Vol. 44, No. 4, April 2006 Large-Eddy Simulation and Acoustic Analysis of a Swirled is successfully captured by reactive large-eddy simulation (LES) and analyzed by using a global acoustic energy criterion) is balanced by the acoustic fluxes at the boundaries when reaching the limit cycle. Additionally

355

Sourabh V. Apte 204 Rogers Hall (541) 737 7335  

E-Print Network [OSTI]

-16, 2008. 3. Moin, P., and Apte S.V., "Large-eddy Simulation of Realistic Gas Turbine Combustors," AIAA and Validation Needs for Gas Turbine Combustors). 4. Apte, S.V., and Yang, V., "A Large-eddy Simulation Study Dynamics of Homogeneous Solid Propellant in a Rocket Motor," Combustion and Flame, Vol. 131, pp. 110

Apte, Sourabh V.

356

To link to this article: DOI:10.1016/j.pecs.2012.04.004 URL : http://dx.doi.org/10.1016/j.pecs.2012.04.004  

E-Print Network [OSTI]

flames in gas turbine combustion chambers. (2012) Progress in Energy and Combustion Science, vol. 38 (n.pecs.2012.04.004 #12;Large Eddy Simulations of gaseous flames in gas turbine combustion chambers L Keywords: Large Eddy Simulations Complex geometry Swirled flows Gaseous combustion Turbulent combustion Gas

Paris-Sud XI, Université de

357

SeyedHosseinHezaveh 410-662-2787 | shezaveh@princeton.edu  

E-Print Network [OSTI]

research area: Large eddy simulations of Vertical Axis Wind Turbines M.Sc. | 2008-2011 | Sharif University of technology · Major: Civil and Environmental Engineering · Minor: Hydraulic Structures · Thesis: Numerical Research Interests Hybrid Wind Turbine Design Computational Mechanics Green Energy Large Eddy Simulations

Bou-Zeid, Elie

358

Center for Turbulence Research Annual Research Briefs 2001  

E-Print Network [OSTI]

Center for Turbulence Research Annual Research Briefs 2001 3 Large-eddy simulation of gas turbine, and solver capable of performing large-eddy simulation in geometries as complex as the combustor of a gas-turbine' grids encountered in complex geometries such as the Pratt & Whitney combustor. · Turbulent validations

Apte, Sourabh V.

359

Scanning tone burst eddy-current thermography (S-TBET) for NDT of carbon fiber reinforced plastic (CFRP) components  

SciTech Connect (OSTI)

Tone Burst Eddy Current technique uses eddy current to apply transient heating inside a component and uses a conventional IR camera for visualization of the response to the transient heating. This technique has been earliest demonstrated for metallic components made of AL, Steel, Stainless Steel, etc., and for detection of cracks, corrosion and adhesive dis-bonds. Although, not nearly as conducting as metals, the Carbon Fibre Reinforced Plastic (CFRP) material absorbs measurable electromagnetic radiation in the frequency range above 10 kHz. When the surface temperature is observed on the surface that is being heated (defined as the surface just beneath and slightly to one side of the heating coil), the surface temperature increases with increasing frequency because the internal heating increases with frequency. A 2-D anisotropic transient Eddy current heating and thermal conduction model has been developed that provides a reasonable description of the processes described above. The inherent anisotropy of CFRP laminates is included in this model by calculating the heating due to three superimposed, tightly coupled isotropic layers having a specified ply-layup. The experimental apparatus consists of an induction heating coil and an IR camera with low NETD and high frame rates. The coil is moved over the sample using a stepper motor controlled manipulator. The IR data recording is synchronized with the motion control to provide a movie of the surface temperature over time. Several components were evaluated for detection of impact damage, location of stiffeners, etc. on CFRP components.

Libin, M. N.; Maxfield, B. W.; Balasubramanian, Krishnan [Centre for Nondestructive Evaluation, Indian Institute of Technology Madras, Chennai 600036 (India)

2014-02-18T23:59:59.000Z

360

EDDY CURRENT EFFECT OF THE BNL-AGS VACUUM CHAMBER ON THE OPTICS OF THE BNL-AGS SYNCHROTRON.  

SciTech Connect (OSTI)

During the acceleration cycle of the AGS synchrotron, eddy currents are generated within the walls of the vacuum chambers of the AGS main magnets. The vacuum chambers have elliptical cross section, are made of inconel material with a wall thickness of 2 mm and are placed within the gap of the combined-function main magnets of the AGS synchrotron. The generation of the eddy currents in the walls of the vacuum chambers, creates various magnetic multipoles, which affect the optics of the AGS machine. In this report these magnetic multipoles are calculated for various time interval starting at the acceleration cycle, where the magnetic field of the main magnet is {approx}0.1 T, and ending before the beam extraction process, where the magnetic field of the main magnet is almost constant at {approx}1.1 T. The calculations show that the magnetic multipoles generated by the eddy-currents affect the optics of the AGS synchrotron during the acceleration cycle and in particular at low magnetic fields of the main magnet. Their effect is too weak to affect the optics of the AGS machine during beam extraction at the nominal energies.

TSOUPAS,N.; AHRENS,L.; BROWN,K.A.; GLENN,J.W.; GARDNER,K.

1999-03-29T23:59:59.000Z

Note: This page contains sample records for the topic "large eddy simulation" 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

Deriving Daytime Variables From the AmeriFlux Standard Eddy Covariance Data Set  

SciTech Connect (OSTI)

A gap-filled, quality assessed eddy covariance dataset has recently become available for the AmeriFluxnetwork. This dataset uses standard processing and produces commonly used science variables. This shared dataset enables robust comparisons across different analyses. Of course, there are many remaining questions. One of those is how to define 'during the day' which is an important concept for many analyses. Some studies have used local time ?for example 9am to 5pm; others have used thresholds on photosynthetic active radiation (PAR). A related question is how to derive quantities such as the Bowen ratio. Most studies compute the ratio of the averages of the latent heat (LE) and sensible heat (H). In this study, we use different methods of defining 'during the day' for GPP, LE, and H. We evaluate the differences between methods in two ways. First, we look at a number of statistics of GPP. Second, we look at differences in the derived Bowen ratio. Our goal is not science per se, but rather informatics in support of the science.

Ingen, Catharine van; Agarwal, Deborah A; Humphrey, Marty; Li, Jie

2008-12-06T23:59:59.000Z

362

Tutorial: Parallel Simulation on Supercomputers  

SciTech Connect (OSTI)

This tutorial introduces typical hardware and software characteristics of extant and emerging supercomputing platforms, and presents issues and solutions in executing large-scale parallel discrete event simulation scenarios on such high performance computing systems. Covered topics include synchronization, model organization, example applications, and observed performance from illustrative large-scale runs.

Perumalla, Kalyan S [ORNL

2012-01-01T23:59:59.000Z

363

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

364

Reduced Mandated Inspection by Remote Field Eddy Current Inspection of Unpiggable Pipelines  

SciTech Connect (OSTI)

The Remote Field Eddy Current (RFEC) technique is ideal for inspecting unpiggable pipelines because all of its components can be made much smaller than the diameter of the pipe to be inspected. For this reason, RFEC was chosen as a technology for unpiggable pipeline inspections by DOE-NETL with the support of OTD and PRCI, to be integrated with platforms selected by DOENETL. As part of the project, the RFEC laboratory facilities were upgraded and data collection was made nearly autonomous. The resulting improved data collection speeds allowed GTI to test more variables to improve the performance of the combined RFEC and platform technologies. Tests were conducted on 6-, 8-, and 12-inch seamless and seam-welded pipes. Testing on the 6-inch pipes included using seven exciter coils, each of different geometry with an initial focus on preparing the technology for use on an autonomous robotic platform with limited battery capacity. Reductions in power consumption proved successful. Tests with metal components similar to the Explorer II modules were performed to check for interference with the electromagnetic fields. The results of these tests indicated RFEC would be able to produce quality inspections while on the robot. Mechanical constraints imposed by the platform, power requirements, control and communication protocols, and potential busses and connectors were addressed. Much work went into sensor module design including the mechanics and electronic diagrams and schematics. GTI participated in two Technology Demonstrations for inspection technologies held at Battelle Laboratories. GTI showed excellent detection and sizing abilities for natural corrosion. Following the demonstration, module building commenced but was stopped when funding reductions did not permit continued development for the selected robotic platform. Conference calls were held between GTI and its sponsors to resolve the issue of how to proceed with reduced funding. The project was rescoped for 10-16-inch pipes with the intent of looking at lower cost, easier to implement, tethered platform applications. OTD ended its sponsorship.

Albert Teitsma; Julie Maupin

2006-09-29T23:59:59.000Z

365

Acceptance testing of the eddy current probes for measurement of aluminum hydroxide coating thickness on K West Basin fuel elements  

SciTech Connect (OSTI)

During a recent visual inspection campaign of fuel elements stored in the K West Basin, it was noted that fuel elements contained in sealed aluminum canisters had a heavy translucent type coating on their surfaces (Pitner 1997a). Subsequent sampling of this coating in a hot cell (Pitner 1997b) and analysis of the material identified it as aluminum hydroxide. Because of the relatively high water content of this material, safety related concerns are raised with respect to long term storage of this fuel in Multi-Canister Overpacks (MCOs). A campaign in the basin is planned to demonstrate whether this coating can be removed by mechanical brushing (Bridges 1998). Part of this campaign involves before-and-after measurements of the coating thickness to determine the effectiveness of coating removal by the brushing machine. Measurements of the as-deposited coating thickness on multiple fuel elements are also expected to provide total coating inventory information needed for MCO safety evaluations. The measurement technique must be capable of measuring coating thicknesses on the order of several mils, with a measurement accuracy of 0.5 mil. Several different methods for quantitatively measuring these thin coatings were considered in selecting the most promising approach. Ultrasonic measurement was investigated, but it was determined that due to the thin coating depth and the high water content of the material, the signal would likely pass directly through to the cladding without ever sensing the coating surface. X-ray fluorescence was also identified as a candidate technique, but would not work because the high gamma background from the irradiated fuel would swamp out the low energy aluminum signal. Laser interferometry could possibly be applied, but considerable development would be required and it was considered to be high risk on a short term basis. The consensus reached was that standard eddy current techniques for coating thickness measurement had the best chance for success in this endeavor. If proper placement and alignment of the eddy current measurement probe on the coating could be achieved, the thickness of this non-conductive coating over the conductive fuel cladding (Zircaloy 2) should be measurable based on magnetic stand-off aspects. Eddy current devices are routinely used to measure paint coating thicknesses on metal surfaces in this regard. The purpose of this report is to document the development and acceptance testing of the eddy current system conducted to qualify its use for the measurement of aluminum hydroxide coating thicknesses on fuel stored in the K West Basin.

Pitner, A.L.

1998-08-21T23:59:59.000Z

366

Experimental development of the predictive relations for the eddy exchange coefficients for momentum and heat in the atmospheric boundary layer  

E-Print Network [OSTI]

, increase in w by removing the dummy -1 bases was 4. 2 cm/sec , and u for these runs was 330 cm/sec -I ?? Using sin [w/u] as a measure of the tilt of the wind field gave an inclination of . 72', in fair agreement with KAIMAL's relation. Therefore.... '?'illlam H. Clayton Direct measurements of the eddy fluxes of mo. . . entum and heat were. made in the atmospheric boundary layer simultaneously with measurements of the profiles of average wind velocity and tempera- ture to evaluate the capability...

Jensen, Paul Alfred

2012-06-07T23:59:59.000Z

367

Renaud_Eddy_Article -accede_document.php http://cemadoc.irstea.fr/exl-php/util/documents/accede_document.php 1 sur 15 28/01/2014 15:30  

E-Print Network [OSTI]

Renaud_Eddy_Article - accede_document.php http://cemadoc.irstea.fr/exl-php/util/documents/accede_document.php Manuscrit auteur, publié dans "Efficient 2013, Paris : France (2013)" #12;Renaud_Eddy_Article - accede_document.php http://cemadoc.irstea.fr/exl-php/util/documents/accede_document.php 2 sur 15 28/01/2014 15

Boyer, Edmond

368

E-Print Network 3.0 - advanced computer simulations Sample Search...  

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

Powered by Explorit Topic List Advanced Search Sample search results for: advanced computer simulations Page: << < 1 2 3 4 5 > >> 1 Simulation of Advanced Large-Scale HPC...

369

Simulation of a plant minicomputer in reactor control room simulator  

SciTech Connect (OSTI)

A control room simulator for the N-Reactor at Hanford is being developed. An important aspect of reactor operation is provided by the plant minicomputer. This paper discusses the simulation of the plant minicomputer. The original commitments in developing the model are set out, as well as the actual requirements at the start of implementation of the model. Original estimates of costs and times for the simulation are presented; actual costs and times were lower by large factors, and the reasons for better performance are examined.

Forrester, A.; Anderson, J.L.

1984-12-07T23:59:59.000Z

370

Simulating Cosmic Reionization  

E-Print Network [OSTI]

The Cosmic Dark Ages and the Epoch of Reionization constitute a crucial missing link in our understanding of the evolution of the intergalactic medium and the formation and evolution of galaxies. Due to the complex nature of this global process it is best studied through large-scale numerical simulations. This presents considerable computational challenges. The dominant contributors of ionizing radiation were dwarf galaxies. These tiny galaxies must be resolved in very large cosmological volumes in order to derive their clustering properties and the corresponding observational signatures correctly, which makes this one of the most challenging problems of numerical cosmology. We have recently performed the largest and most detailed simulations of the formation of early cosmological large-scale structures and their radiative feedback leading to cosmic reionization. This was achieved by running extremely large (up to 29 billion-particle) N-body simulations of the formation of the Cosmic Web, with enough particles and sufficient force resolution to resolve all the galactic halos with total masses larger than 10^8 Solar masses in computational volumes of up to (163 Mpc)^3. These results were then post-processed by propagating the ionizing radiation from all sources by using fast and accurate ray-tracing radiative transfer method. Both of our codes are parallelized using a combination of MPI and OpenMP and to this date have been run efficiently on up to 2048 cores (N-body) and up to 10000 cores (radiative transfer) on the newly-deployed Sun Constellation Linux Cluster at the Texas Advanced Computing Center. In this paper we describe our codes, parallelization strategies, scaling and some preliminary scientific results. (abridged)

Ilian T. Iliev; Paul R. Shapiro; Garrelt Mellema; Hugh Merz; Ue-Li Pen

2008-06-17T23:59:59.000Z

371

Generated using version 3.0 of the official AMS LATEX template Assessing the Roles of Three Eddy Types in Restratifying the  

E-Print Network [OSTI]

after deep convection1 . The30 process is governed both by warming due to solar radiation in summer over the upper 1600 m is provided by lateral heat fluxes (Yashayaev and Loder 2009), but solar different eddy types in this process are assessed using an idealized model of the Labrador Sea

Drijfhout, Sybren

372

Semantic Awareness in Product Lifecycle Management Systems Casey James Baker, Douglas Eddy, Dr. Sundar Krishnamurty, Dr. Ian Grosse, Dr. Jack Wileden  

E-Print Network [OSTI]

Semantic Awareness in Product Lifecycle Management Systems Casey James Baker, Douglas Eddy, Dr enterprises turn to Product Lifecycle Management (PLM) systems to organize product development and to reduce), in which the PLM system was used to help with the design and fabrication of a product. Windchill

Mountziaris, T. J.

373

Intercomparison of Sensible Heat Flux from Large Aperture Scintillometer and Eddy Covariance Methods: Field Experiment over a Homogeneous Semi-arid Region  

E-Print Network [OSTI]

of satellite remote sensing sensible heat-?ux estimates dueremote sensing algorithms. A typical approach identi?es spectral bands particularly sensitive to surface heat ?

Zeweldi, Dawit A.; Gebremichael, Mekonnen; Wang, Junming; Sammis, Theodore; Kleissl, Jan; Miller, David

2010-01-01T23:59:59.000Z

374

Intercomparison of Sensible Heat Flux from Large Aperture Scintillometer and Eddy Covariance Methods: Field Experiment over a Homogeneous Semi-arid Region  

E-Print Network [OSTI]

uctuations of vertical wind speed and air temperature at abetween ?uctuations of vertical wind speed and ?uctuationsT is the covariance between vertical wind speed (w) and air

Zeweldi, Dawit A.; Gebremichael, Mekonnen; Wang, Junming; Sammis, Theodore; Kleissl, Jan; Miller, David

2010-01-01T23:59:59.000Z

375

Simulation of SMES connected to a large scale system  

E-Print Network [OSTI]

Diagram 14 0 0 Q I O IO O I Cl ? l 0 0 0 Co UJ 0 CO 0 0 0 0 0 N Cl 0 Ql 0 0 0 ICI O I CO O N O QI V CI3 llJ I Ql CL Ql Ql (D Ql QQ II 0 0 I 0 Cl D a 0 O 0 0 0 0 $3+$ O)UI ISMOd SAI)OBSJ 4b +c SVC SMES... Ch T3 O 0 O 0) Ch hI E Ch CO- Ch b 0 OO O Q P CCI P& I? VI LL O O O III O (s(s(pm) uoqma~e~~y 26 n5 llJ 4) 0 0 O C 0 e N &0 &D 0 rn 0 V& Z 333 EZZ I PJ N W LU 4I CL (Y IX 0 0 M Ot4 0 0 CV 0 0 0 0 (MW) S3WS...

Gulde, James Ernst

1988-01-01T23:59:59.000Z

376

Simulation and Optimization of Large-Scale Controlled Reservoir...  

Office of Environmental Management (EM)

Activities Dr. Gene LeBoeuf, Ph.D., P.E., BCEE Dr. Mark McDonald, Ph.D. Heather Smith Sawyer, P.E. Amy Shaw Vanderbilt University Department of Civil & Environmental...

377

Cosmological Simulations for Large-Scale Sky Surveys | Argonne Leadership  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to User GroupInformationE-GovNatural Gas UsageCosmic FrontierComputing

378

PEBBLES Mechanics Simulation Speedup  

SciTech Connect (OSTI)

Pebble bed reactors contain large numbers of spherical fuel elements arranged randomly. Determining the motion and location of these fuel elements is required for calculating certain parameters of pebble bed reactor operation. These simulations involve hundreds of thousands of pebbles and involve determining the entire core motion as pebbles are recirculated. Single processor algorithms for this are insufficient since they would take decades to centuries of wall-clock time. This paper describes the process of parallelizing and speeding up the PEBBLES pebble mechanics simulation code. Both shared memory programming with the Open Multi-Processing API and distributed memory programming with the Message Passing Interface API are used in simultaneously in this process. A new shared memory lock-less linear time collision detection algorithm is described. This method allows faster detection of pebbles in contact than generic methods. These combine to make full recirculations on AVR sized reactors possible in months of wall clock time.

Joshua J. Cogliati; Abderrafi M. Ougouag

2010-05-01T23:59:59.000Z

379

EDDY CURRENT TESTING OF FERROMAGNETIC MATERIALS: MODELLING OF MULTIPLE FLAWS IN A  

E-Print Network [OSTI]

. Simulation results are obtained through the application of the Volume Integral Method (VIM) [4 integral equation, involving either the electric or the magnetic field, is needed to describe the non-magnetic case completely, in the ferromagnetic case two coupled integral equations have to be solved. Therefore

Paris-Sud XI, Université de

380

Moist thermodynamics of the Madden-Julian Oscillation in a cloud resolving simulation  

SciTech Connect (OSTI)

The moist thermodynamic processes that determine the scale and energy of the Madden-Julian Oscillation are investigated using moisture and eddy available potential energy (EAPE) budget analyses on a high resolution regional model simulation. The two MJO episodes observed during the winter of 2007-2008 are realistically simulated. In the model, small differences among the timescales of convective vertical transport, mixing and condensation of moisture determine the timescale of MJO moistening. Furthermore, various cloud types play a damping or destabilizing contribution role in the EAPE budget of the MJO, depending on their characteristic latent heating profile and its covariance with the temperature fluctuations. The results are used identify possible sources of the difficulties in simulating MJO in low resolution models that rely on cumulus parameterizations.

Hagos, Samson M.; Leung, Lai-Yung R.

2011-10-31T23:59:59.000Z

Note: This page contains sample records for the topic "large eddy simulation" 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 low cost high flux solar simulator  

E-Print Network [OSTI]

A low cost, high flux, large area solar simulator has been designed, built and characterized for the purpose of studying optical melting and light absorption behavior of molten salts. Seven 1500 W metal halide outdoor ...

Codd, Daniel S.

382

Computer simulations suggest a new strategy to design enhanced enzymes for biofuels production.  

E-Print Network [OSTI]

Computer simulations suggest a new strategy to design enhanced enzymes for biofuels production. Large-scale computer simulations predict that the addition of glycosylation on carbohydrate Energy Laboratory (NREL) used computer simulation to predict that adding glycosylation

383

Model Validation with Hybrid Dynamic Simulation  

SciTech Connect (OSTI)

Abstract—Model validation has been one of the central topics in power engineering studies for years. As model validation aims at obtaining reasonable models to represent actual behavior of power system components, it has been essential to validate models against actual measurements or known benchmark behavior. System-wide model simulation results can be compared with actual recordings. However, it is difficult to construct a simulation case for a large power system such as the WECC system and to narrow down to problematic models in a large system. Hybrid dynamic simulation with its capability of injecting external signals into dynamic simulation enables rigorous comparison of measurements and simulation in a small subsystem of interest. This paper presents such a model validation methodology with hybrid dynamic simulation. Two application examples on generator and load model validation are presented to show the validity of this model validation methodology. This methodology is further extended for automatic model validation and dichotomous subsystem model validation.

Huang, Zhenyu; Kosterev, Dmitry; Guttromson, Ross T.; Nguyen, Tony B.

2006-06-18T23:59:59.000Z

384

Plasma Turbulence Simulations Reveal Promising Insight for Fusion...  

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

Physics Laboratory (PPPL), a DOE collaborative national center for fusion and plasma research in New Jersey, are running large-scale simulations at the Argonne Leadership...

385

THE BLIND SIMULATION PROBLEM and REGENERATIVE PROCESSES  

E-Print Network [OSTI]

Processes 1 #12; 1 Introduction 1.1 Simulation and importance sampling Large and/or nonlinear stochastic on the order of 10 \\Gamma6 are quite common in stochastic systems. It is clear that a direct simulation(Z i ): The ratio p(\\Delta)=q(\\Delta) will be called the weight function of the importance sam

Bucklew, James Antonio

386

Adaptive Sampling in Hierarchical Simulation  

SciTech Connect (OSTI)

We propose an adaptive sampling methodology for hierarchical multi-scale simulation. The method utilizes a moving kriging interpolation to significantly reduce the number of evaluations of finer-scale response functions to provide essential constitutive information to a coarser-scale simulation model. The underlying interpolation scheme is unstructured and adaptive to handle the transient nature of a simulation. To handle the dynamic construction and searching of a potentially large set of finer-scale response data, we employ a dynamic metric tree database. We study the performance of our adaptive sampling methodology for a two-level multi-scale model involving a coarse-scale finite element simulation and a finer-scale crystal plasticity based constitutive law.

Knap, J; Barton, N R; Hornung, R D; Arsenlis, A; Becker, R; Jefferson, D R

2007-07-09T23:59:59.000Z

387

The Durham ELT adaptive optics simulation platform  

E-Print Network [OSTI]

Adaptive optics systems are essential on all large telescopes where image quality is important. These are complex systems with many design parameters requiring optimisation before good performance can be achieved. The simulation of adaptive optics systems is therefore necessary to categorise the expected performance. This paper describes an adaptive optics simulation platform, developed at Durham University, which can be used to simulate adaptive optics systems on the largest proposed future extremely large telescopes (ELTs) as well as current systems. This platform is modular, object oriented and has the benefit of hardware application acceleration which can be used to improve the simulation performance, essential for ensuring that the run time of a given simulation is acceptable. The simulation platform described here can be highly parallelised using parallelisation techniques suited for adaptive optics simulation, whilst still offering the user complete control while the simulation is running. Results from the simulation of a ground layer adaptive optics system are provided as an example to demonstrate the flexibility of this simulation platform.

Alastair Basden; Timothy Butterley; Richard Myers; Richard Wilson

2006-11-09T23:59:59.000Z

388

A Topological Framework for the Interactive Exploration of Large Scale Turbulent Combustion  

E-Print Network [OSTI]

comparison of terascale combustion simulation data. Mathe-premixed hydrogen ?ames. Combustion and Flame, [7] J. L.of Large Scale Turbulent Combustion Peer-Timo Bremer 1 ,

Bremer, Peer-Timo

2010-01-01T23:59:59.000Z

389

Doctoral Position Aeroelastic Analysis of Large Wind Turbines  

E-Print Network [OSTI]

Doctoral Position Aeroelastic Analysis of Large Wind Turbines In the research project "Aeroelastic Analysis Horizontal-axis wind turbine and numerical model. of Large Wind Turbines" funded by the Ger- man involving the in-house Finite-Element CFD code XNS to enable the simulation of wind turbines. The ability

390

POWER SYSTEMS STABILITY WITH LARGE-SCALE WIND POWER PENETRATION  

E-Print Network [OSTI]

of offshore wind farms, wind power fluctuations may introduce several challenges to reliable power system behaviour due to natural wind fluctuations. The rapid power fluctuations from the large scale wind farms Generation Control (AGC) system which includes large- scale wind farms for long-term stability simulation

Bak-Jensen, Birgitte

391

Distributing MCell Simulations on the Grid  

E-Print Network [OSTI]

Distributing MCell Simulations on the Grid Henri Casanova casanova@cs.ucsd.edu Tom Bartol The Computational Grid [21] is a promising platform for the deployment of large-scale scientific and engineering that structure, PSAs are particularly well suited to the Grid infrastructure and can be deployed on very large

Sejnowski, Terrence J.

392

A restructurable logic simulator  

E-Print Network [OSTI]

, notably logic simulators. This paper reviews the event-driven simulation algorithm used by most software- based simulators and a handful of the existing special-purpose hardware-based logic simulation accelerators. A new hardware-based accelerator... architecture is then presented, that of the restructurab)e logic simulator. This accelerator is based on a, memory-like module. referred to as the restructurable logic simulation accelerator, that essentially "stores" a portion of the network to be simulated...

Ledford, Gordon Lee

1985-01-01T23:59:59.000Z

393

A pulsed eddy current probe for inspection of support plates from within Alloy-800 steam generator tubes  

SciTech Connect (OSTI)

Support plate degradation and fouling in nuclear steam generators (SGs) can lead to SG tube corrosion and loss of efficiency. Inspection and monitoring of these conditions can be integrated with preventive maintenance programs, thereby advancing station-life management processes. A prototype pulsed eddy current (PEC) probe, targeting inspection issues associated with SG tubes in SS410 tube support plate structures, has been developed using commercial finite element (FE) software. FE modeling was used to identify appropriate driver and pickup coil configurations for optimum sensitivity to changes in gap and offset for Alloy-800 SG tubes passing through 25 mm thick SS410 support plates. Experimental measurements using a probe that was manufactured based on the modeled configuration, were used to confirm the sensitivity of differential PEC signals to changes in relative position of the tube within the tube support plate holes. Models investigated the effect of shift and tilt of tube with respect to hole centers. Near hole centers and for small shifts, modeled signal amplitudes from the differentially connected coil pairs were observed to change linearly with tube shift. This was in agreement with experimentally measured TEC coil response. The work paves the way for development of a system targeting the inspection and evaluation of support plate structures in steam generators.

Krause, T. W.; Babbar, V. K.; Underhill, P. R. [Department of Physics, Royal Military College of Canada, Kingston, ON (Canada)

2014-02-18T23:59:59.000Z

394

Composting Large Animal Carcasses  

E-Print Network [OSTI]

Disposing of large animal carcasses can be a problem for agricultural producers. Composting is a simple, low-cost method that yields a useful product that can be used as fertilizer. In this publication you'll learn the basics of composting, how...

Auvermann, Brent W.; Mukhtar, Saqib; Heflin, Kevin

2006-10-31T23:59:59.000Z

395

Simulating spin models on GPU  

E-Print Network [OSTI]

Over the last couple of years it has been realized that the vast computational power of graphics processing units (GPUs) could be harvested for purposes other than the video game industry. This power, which at least nominally exceeds that of current CPUs by large factors, results from the relative simplicity of the GPU architectures as compared to CPUs, combined with a large number of parallel processing units on a single chip. To benefit from this setup for general computing purposes, the problems at hand need to be prepared in a way to profit from the inherent parallelism and hierarchical structure of memory accesses. In this contribution I discuss the performance potential for simulating spin models, such as the Ising model, on GPU as compared to conventional simulations on CPU.

Martin Weigel

2011-06-07T23:59:59.000Z

396

Simulating chemistry using quantum computers  

E-Print Network [OSTI]

The difficulty of simulating quantum systems, well-known to quantum chemists, prompted the idea of quantum computation. One can avoid the steep scaling associated with the exact simulation of increasingly large quantum systems on conventional computers, by mapping the quantum system to another, more controllable one. In this review, we discuss to what extent the ideas in quantum computation, now a well-established field, have been applied to chemical problems. We describe algorithms that achieve significant advantages for the electronic-structure problem, the simulation of chemical dynamics, protein folding, and other tasks. Although theory is still ahead of experiment, we outline recent advances that have led to the first chemical calculations on small quantum information processors.

Ivan Kassal; James D. Whitfield; Alejandro Perdomo-Ortiz; Man-Hong Yung; Alán Aspuru-Guzik

2010-07-15T23:59:59.000Z

397

CURRICULUM VITAE CHARLES MENEVEAU  

E-Print Network [OSTI]

, "Large Eddy Simulation study of scalar transport in fully developed wind-turbine array boundary layers" (2011), Phys. Fluids (submitted). 3) K. Bai, C. Meneveau & J. Katz, "Near-wake turbulent flow structure

Meneveau, Charles

398

SciTech Connect: Comparison of the Dynamic Wake Meandering Model...  

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

Wake Meandering Model, Large-Eddy Simulation, and Field Data at the Egmond aan Zee Offshore Wind Plant: Preprint Citation Details In-Document Search Title: Comparison of the...

399

air-breathing missile configurations: Topics by E-print Network  

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

recurrence satisfied by the Stirling numbers of the second kind. Abrams, Aaron; Hower, Valerie 2010-01-01 99 Large-eddy Simulation of NASA LaRC Coaxial He-O2Air Jet. Open...

400

Intelligent interface for design and simulation  

SciTech Connect (OSTI)

We are developing a system composed of intelligent interfaces, expert systems, and databases that uses artificial intelligence techniques to simplify the use of large simulation codes and to help design complicated physical devices. The simulation codes are used in analyzing and designing weapons, and the devices are themselves parts of weapon systems. From a designer's point of view, the simulation process is the same no matter what is being simulated. In the course of developing two intelligent interfaces for the design of nuclear weapons, we have found that data-driven programming is a useful technique for implementing an open-ended user interface to assist the designer. We discuss the simulation process as it is done now and as it could be done with intelligent interfaces. We then discuss the use of data-driven programming in a database environment to support an interface for an arbitrary number of simulation codes. 3 figs.

Draisin, W.; Peter, E.

1986-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "large eddy simulation" 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

Modeling Molecular Dynamics from Simulations  

SciTech Connect (OSTI)

Many important processes in biology occur at the molecular scale. A detailed understanding of these processes can lead to significant advances in the medical and life sciences. For example, many diseases are caused by protein aggregation or misfolding. One approach to studying these systems is to use physically-based computational simulations to model the interactions and movement of the molecules. While molecular simulations are computationally expensive, it is now possible to simulate many independent molecular dynamics trajectories in a parallel fashion by using super- or distributed- computing methods such as Folding@Home or Blue Gene. The analysis of these large, high-dimensional data sets presents new computational challenges. In this seminar, I will discuss a novel approach to analyzing large ensembles of molecular dynamics trajectories to generate a compact model of the dynamics. This model groups conformations into discrete states and describes the dynamics as Markovian, or history-independent, transitions between the states. I will discuss why the Markovian state model (MSM) is suitable for macromolecular dynamics, and how it can be used to answer many interesting and relevant questions about the molecular system. I will also discuss many of the computational and statistical challenges in building such a model, such as how to appropriately cluster conformations, determine the statistical reliability, and efficiently design new simulations.

Hinrichs, Nina Singhal (University of Chicago) [University of Chicago

2009-01-28T23:59:59.000Z

402

Building Performance Simulation  

E-Print Network [OSTI]

usage simulation. PhD Thesis, Eindhoven University of Technology,usage simulation. PhD thesis, Eindhoven University of Technology,

Hong, Tianzhen

2014-01-01T23:59:59.000Z

403

Simulating flame lift-off characteristics of diesel and biodiesel fuels using detailed chemical-kinetic mechanisms and LES turbulence model.  

SciTech Connect (OSTI)

Combustion in direct-injection diesel engines occurs in a lifted, turbulent diffusion flame mode. Numerous studies indicate that the combustion and emissions in such engines are strongly influenced by the lifted flame characteristics, which are in turn determined by fuel and air mixing in the upstream region of the lifted flame, and consequently by the liquid breakup and spray development processes. From a numerical standpoint, these spray combustion processes depend heavily on the choice of underlying spray, combustion, and turbulence models. The present numerical study investigates the influence of different chemical kinetic mechanisms for diesel and biodiesel fuels, as well as Reynolds-averaged Navier-Stokes (RANS) and large eddy simulation (LES) turbulence models on predicting flame lift-off lengths (LOLs) and ignition delays. Specifically, two chemical kinetic mechanisms for n-heptane (NHPT) and three for biodiesel surrogates are investigated. In addition, the RNG k-{epsilon} (RANS) model is compared to the Smagorinsky based LES turbulence model. Using adaptive grid resolution, minimum grid sizes of 250 {micro}m and 125 {micro}m were obtained for the RANS and LES cases respectively. Validations of these models were performed against experimental data from Sandia National Laboratories in a constant volume combustion chamber. Ignition delay and flame lift-off validations were performed at different ambient temperature conditions. The LES model predicts lower ignition delays and qualitatively better flame structures compared to the RNG k-{epsilon} model. The use of realistic chemistry and a ternary surrogate mixture, which consists of methyl decanoate, methyl 9-decenoate, and NHPT, results in better predicted LOLs and ignition delays. For diesel fuel though, only marginal improvements are observed by using larger size mechanisms. However, these improved predictions come at a significant increase in computational cost.

Som, S; Longman, D. E.; Luo, Z; Plomer, M; Lu, T; Senecal, P.K.; Pomraning, E (Energy Systems); (Univ. of Connecticut); (CONVERGENT Science)

2012-01-01T23:59:59.000Z

404

ATLAS Fast Tracker Simulation Challenges  

E-Print Network [OSTI]

To deal with Big Data flood from the ATLAS detector most events have to be rejected in the trigger system. the trigger rejection is complicated by the presence of a large number of minimum-bias events – the pileup. To limit pileup effects in the high luminosity environment of the LHC Run-2, ATLAS relies on full tracking provided by the Fast TracKer (FTK) implemented with custom electronics. The FTK data processing pipeline has to be simulated in preparation for LHC upgrades to support electronics design and develop trigger strategies at high luminosity. The simulation of the FTK - a highly parallelized system - has inherent performance bottlenecks on general-purpose CPUs. To take advantage of the Grid Computing power, the FTK simulation is integrated with Monte Carlo simulations at the Production System level above the ATLAS workload management system PanDA. We report on ATLAS experience with FTK simulations on the Grid and next steps for accommodating the growing requirements for resources during the LHC R...

Adelman, Jahred; The ATLAS collaboration; Borodin, Mikhail; Chakraborty, Dhiman; García Navarro, José Enrique; Golubkov, Dmitry; Kama, Sami; Panitkin, Sergey; Smirnov, Yuri; Stewart, Graeme; Tompkins, Lauren; Vaniachine, Alexandre; Volpi, Guido

2015-01-01T23:59:59.000Z

405

Final report on the project entitled "The Effects of Disturbance & Climate on Carbon Storage & the Exchanges of CO2 Water Vapor & Energy Exchange of Evergreen Coniferous Forests in the Pacific Northwest: Integration of Eddy Flux, Plant and Soil Measurements at a Cluster of Supersites"  

SciTech Connect (OSTI)

This is the final technical report containing a summary of all findings with regard to the following objectives of the project: (1) To quantify and understand the effects of wildfire on carbon storage and the exchanges of energy, CO2, and water vapor in a chronosequence of ponderosa pine (disturbance gradient); (2) To investigate the effects of seasonal and interannual variation in climate on carbon storage and the exchanges of energy, CO2, and water vapor in mature conifer forests in two climate zones: mesic 40-yr old Douglas-fir and semi-arid 60-yr old ponderosa pine (climate gradient); (3) To reduce uncertainty in estimates of CO2 feedbacks to the atmosphere by providing an improved model formulation for existing biosphere-atmosphere models; and (4) To provide high quality data for AmeriFlux and the NACP on micrometeorology, meteorology, and biology of these systems. Objective (1): A study integrating satellite remote sensing, AmeriFlux data, and field surveys in a simulation modeling framework estimated that the pyrogenic carbon emissions, tree mortality, and net carbon exchange associated with four large wildfires that burned ~50,000 hectares in 2002-2003 were equivalent to 2.4% of Oregon statewide anthropogenic carbon emissions over the same two-year period. Most emissions were from the combustion of the forest floor and understory vegetation, and only about 1% of live tree mass was combusted on average. Objective (2): A study of multi-year flux records across a chronosequence of ponderosa pine forests yielded that the net carbon uptake is over three times greater at a mature pine forest compared with young pine. The larger leaf area and wetter and cooler soils of the mature forest mainly caused this effect. A study analyzing seven years of carbon and water dynamics showed that interannual and seasonal variability of net carbon exchange was primarily related to variability in growing season length, which was a linear function of plant-available soil moisture in spring and early summer. A multi-year drought (2001-2003) led to a significant reduction of net ecosystem exchange due to carry-over effects in soil moisture and carbohydrate reserves in plant-tissue. In the same forest, the interannual variability in the rate carbon is lost from the soil and forest floor is considerable and related to the variability in tree growth as much as it is to variability in soil climatic conditions. Objective (3): Flux data from the mature ponderosa pine site support a physical basis for filtering nighttime data with friction velocity above the canopy. An analysis of wind fields and heat transport in the subcanopy at the mesic 40-year old Douglas site yielded that the non-linear structure and behavior of spatial temperature gradients and the flow field require enhanced sensor networks to estimate advective fluxes in the subcanopy of forest to close the surface energy balance in forests. Reliable estimates for flux uncertainties are needed to improve model validation and data assimilation in process-based carbon models, inverse modeling studies and model-data synthesis, where the uncertainties may be as important as the fluxes themselves. An analysis of the time scale dependence of the random and flux sampling error yielded that the additional flux obtained by increasing the perturbation timescale beyond about 10 minutes is dominated by random sampling error, and therefore little confidence can be placed in its value. Artificial correlation between gross ecosystem productivity (GEP) and ecosystem respiration (Re) is a consequence of flux partitioning of eddy covariance flux data when GEP is computed as the difference between NEE and computed daytime Re (e.g. using nighttime Re extrapolated into daytime using soil or air temperatures). Tower-data must be adequately spatially averaged before comparison to gridded model output as the time variability of both is inherently different. The eddy-covariance data collected at the mature ponderosa pine site and the mesic Douglas fir site were used to develop and evaluate a new method to extra

Beverly E. Law (PI), Christoph K. Thomas (CoI)

2011-09-20T23:59:59.000Z

406

Large Business Development Program (Illinois)  

Broader source: Energy.gov [DOE]

The Large Business Development Program, administered by the Illinois Department of Commerce and Economic Opportunity, provides grants to large businesses for bondable business activities, including...

407

Large Magnetization at Carbon Surfaces  

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

Large Magnetization at Carbon Surfaces Large Magnetization at Carbon Surfaces Print Wednesday, 31 August 2011 00:00 From organic matter to pencil lead, carbon is a versatile...

408

Quantum noise in large-scale coherent nonlinear photonic circuits  

E-Print Network [OSTI]

A semiclassical simulation approach is presented for studying quantum noise in large-scale photonic circuits incorporating an ideal Kerr nonlinearity. A circuit solver is used to generate matrices defining a set of stochastic differential equations, in which the resonator field variables represent random samplings of the Wigner quasi-probability distributions. Although the semiclassical approach involves making a large-photon-number approximation, tests on one- and two-resonator circuits indicate satisfactory agreement between the semiclassical and full-quantum simulation results in the parameter regime of interest. The semiclassical model is used to simulate random errors in a large-scale circuit that contains 88 resonators and hundreds of components in total, and functions as a 4-bit ripple counter. The error rate as a function of on-state photon number is examined, and it is observed that the quantum fluctuation amplitudes do not increase as signals propagate through the circuit, an important property for scalability.

Charles Santori; Jason S. Pelc; Raymond G. Beausoleil; Nikolas Tezak; Ryan Hamerly; Hideo Mabuchi

2014-05-27T23:59:59.000Z

409

Large Spectral Library Problem  

SciTech Connect (OSTI)

Hyperspectral imaging produces a spectrum or vector at each image pixel. These spectra can be used to identify materials present in the image. In some cases, spectral libraries representing atmospheric chemicals or ground materials are available. The challenge is to determine if any of the library chemicals or materials exist in the hyperspectral image. The number of spectra in these libraries can be very large, far exceeding the number of spectral channels collected in the ¯eld. Suppose an image pixel contains a mixture of p spectra from the library. Is it possible to uniquely identify these p spectra? We address this question in this paper and refer to it as the Large Spectral Library (LSL) problem. We show how to determine if unique identi¯cation is possible for any given library. We also show that if p is small compared to the number of spectral channels, it is very likely that unique identi¯cation is possible. We show that unique identi¯cation becomes less likely as p increases.

Chilton, Lawrence K.; Walsh, Stephen J.

2008-10-03T23:59:59.000Z

410

Low permeability gas reservoir production using large hydraulic fractures  

E-Print Network [OSTI]

extending up to three thousand feet from the producing well. Also, a model simulating a nuclear cavity was designed. This model simulated a well containing an eighty foot radius cavity with a fractured zone of one hundred times the reservoir permeability... of each system was prepared. The results of this study showed that all fractures of greater than one thousand foot radius had greater productivity and greater cumu- lative gas produced than did the nuclear cavity. It appears that large hydraulic...

Holditch, Stephen A

1970-01-01T23:59:59.000Z

411

Web Interface Call Simulator  

E-Print Network [OSTI]

Web Interface Call Simulator Stage Description Web Interface for VoIP Call Simulator Net) Version 1.0 ­ 3/09/2012 Page 1 of 6 #12;Web Interface Call Simulator Version 1.0 ­ 3/09/2012 Page 2 of 6 #12;Web Interface Call Simulator Document Control Version Date Notes 1.0 25/8/2012 Reviewed

Ernst, Damien

412

Scaling self-organizing maps to model large cortical networks  

E-Print Network [OSTI]

Self-organizing computational models with specific intracortical connections can explain many functional features of visual cortex, such as topographic orientation and ocular dominance maps. However, due to their computational requirements, it is difficult to use such detailed models to study large-scale phenomena like object segmentation and binding, object recognition, tilt illusions, optic flow, and fovea periphery interaction. This paper introduces two techniques that make large simulations practical. First, a set of general linear scaling equations for the RF-LISSOM self-organizing model is derived and shown to result in quantitatively equivalent maps over a wide range of simulation sizes. This capability makes it possible to debug small simulations and then scale them up to larger simulations only when needed. The scaling equations also facilitate the comparison of biological maps and parameters between individuals and species with different brain region sizes. Second, the equations are combined into a new growing map method called GLISSOM, which dramatically reduces the memory and computational requirements of large self-organizing networks. With GLISSOM it should be possible to simulate all of human V1 at the single-column level using existing supercomputers, making detailed computational study of large-scale phenomena possible.

2004-01-01T23:59:59.000Z

413

Large Superconducting Magnet Systems  

E-Print Network [OSTI]

The increase of energy in accelerators over the past decades has led to the design of superconducting magnets for both accelerators and the associated detectors. The use of Nb?Ti superconducting materials allows an increase in the dipole field by up to 10 T compared with the maximum field of 2 T in a conventional magnet. The field bending of the particles in the detectors and generated by the magnets can also be increased. New materials, such as Nb3Sn and high temperature superconductor (HTS) conductors, can open the way to higher fields, in the range 13–20 T. The latest generations of fusion machines producing hot plasma also use large superconducting magnet systems.

Védrine, P

2014-01-01T23:59:59.000Z

414

An investigation of the vertical and temporal distributions of the eddy heat-diffusion coefficient near the earth's surface under fair-weather conditions  

E-Print Network [OSTI]

facilities avail- able at the Data Processing Center (DPC), Texas A&M Univer- sity, this investigation would not have been temporally possible. Deep appreciation goes to all DPC personnel for their tireless assistance. Thanks must go to Mr. Lundin, my...-Weather Conditions (January 1965) Eugene Y J, Wong, B. S, , Texas A&M University Directed by: Dr. Kenneth C. Brundidge A numerical scheme was devised to solve the Tavlor heat-diffusion equation for values of the eddy heat- diffusion coefficient, K, using a...

Wong, Eugene You June

1965-01-01T23:59:59.000Z

415

Xyce parallel electronic simulator release notes.  

SciTech Connect (OSTI)

The Xyce Parallel Electronic Simulator has been written to support, in a rigorous manner, the simulation needs of the Sandia National Laboratories electrical designers. Specific requirements include, among others, the ability to solve extremely large circuit problems by supporting large-scale parallel computing platforms, improved numerical performance and object-oriented code design and implementation. The Xyce release notes describe: Hardware and software requirements New features and enhancements Any defects fixed since the last release Current known defects and defect workarounds For up-to-date information not available at the time these notes were produced, please visit the Xyce web page at http://www.cs.sandia.gov/xyce.

Keiter, Eric Richard; Hoekstra, Robert John; Mei, Ting; Russo, Thomas V.; Schiek, Richard Louis; Thornquist, Heidi K.; Rankin, Eric Lamont; Coffey, Todd Stirling; Pawlowski, Roger Patrick; Santarelli, Keith R.

2010-05-01T23:59:59.000Z

416

Mathematical Caricature of Large Waves  

E-Print Network [OSTI]

The Kadomtsev-Petviiashvili equation is considered as a mathematical caricature of large and rogue waves.

Mikhail Kovalyov

2014-03-21T23:59:59.000Z

417

A NEW GENERATION CHEMICAL FLOODING SIMULATOR  

SciTech Connect (OSTI)

The premise of this research is that a general-purpose reservoir simulator for several improved oil recovery processes can and should be developed so that high-resolution simulations of a variety of very large and difficult problems can be achieved using state-of-the-art algorithms and computers. Such a simulator is not currently available to the industry. The goal of this proposed research is to develop a new-generation chemical flooding simulator that is capable of efficiently and accurately simulating oil reservoirs with at least a million gridblocks in less than one day on massively parallel computers. Task 1 is the formulation and development of solution scheme, Task 2 is the implementation of the chemical module, and Task 3 is validation and application. In this final report, we will detail our progress on Tasks 1 through 3 of the project.

Gary A. Pope; Kamy Sepehrnoori; Mojdeh Delshad

2005-01-01T23:59:59.000Z

418

NetStep: a micro-stepped distributed network simulation Olivier Dalle  

E-Print Network [OSTI]

NetStep: a micro-stepped distributed network simulation framework Olivier Dalle Laboratoire I3S UMR This paper presents NetStep, a prototype for the distributed simulation of very large scale network simulations, such as the simulation of peer-to-peer applications. We use sim- ulation micro-steps as a means

Paris-Sud XI, Université de

419

Large scale tracking algorithms.  

SciTech Connect (OSTI)

Low signal-to-noise data processing algorithms for improved detection, tracking, discrimination and situational threat assessment are a key research challenge. As sensor technologies progress, the number of pixels will increase signi cantly. This will result in increased resolution, which could improve object discrimination, but unfortunately, will also result in a significant increase in the number of potential targets to track. Many tracking techniques, like multi-hypothesis trackers, suffer from a combinatorial explosion as the number of potential targets increase. As the resolution increases, the phenomenology applied towards detection algorithms also changes. For low resolution sensors, "blob" tracking is the norm. For higher resolution data, additional information may be employed in the detection and classfication steps. The most challenging scenarios are those where the targets cannot be fully resolved, yet must be tracked and distinguished for neighboring closely spaced objects. Tracking vehicles in an urban environment is an example of such a challenging scenario. This report evaluates several potential tracking algorithms for large-scale tracking in an urban environment.

Hansen, Ross L.; Love, Joshua Alan; Melgaard, David Kennett; Karelitz, David B.; Pitts, Todd Alan; Zollweg, Joshua David; Anderson, Dylan Z.; Nandy, Prabal; Whitlow, Gary L.; Bender, Daniel A.; Byrne, Raymond Harry

2015-01-01T23:59:59.000Z

420

Dynamic Positioning Simulator Dynamic Positioning Simulator  

E-Print Network [OSTI]

Simulator 5 / 24 #12;Dynamic Positioning Simulator Dynamic Positioning Why Dynamic Positioning? Advantages Dynamic Positioning: No tugboats needed; Offshore set-up is quick; Power saving; Precision situations more on Ship: Wind Force Fw = 1 2 air V 2 rw CXw (rw )AT 1 2 air V 2 rw CYw (rw )AL Mw = 1 2 air V 2 rw CMw (rw

Vuik, Kees

Note: This page contains sample records for the topic "large eddy simulation" from the National Library of EnergyBeta (NLEBeta).
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to obtain the most current and comprehensive results.


421

Quantum simulations of physics problems  

SciTech Connect (OSTI)

If a large Quantum Computer (QC) existed today, what type of physical problems could we efficiently simulate on it that we could not efficiently simulate on a classical Turing machine? In this paper we argue that a QC could solve some relevant physical 'questions' more efficiently. The existence of one-to-one mappings between different algebras of observables or between different Hilbert spaces allow us to represent and imitate any physical system by any other one (e.g., a bosonic system by a spin-1/2 system). We explain how these mappings can be performed, and we show quantum networks useful for the efficient evaluation of some physical properties, such as correlation functions and energy spectra.

Somma, R. D. (Rolando D.); Ortiz, G. (Gerardo); Knill, E. H. (Emanuel H.); Gubernatis, J. E.

2003-01-01T23:59:59.000Z

422

Use of Building Automation System Trend Data for Inputs Generation in Bottom-Up Simulation Calibration  

E-Print Network [OSTI]

for analysis and use in simulation is very large. This paper explores automating the process of generating inputs from Building Automation System (BAS) trend data for use in building simulation software. A proof-of-concept prototype called the Automatic...

Zibin, N. F.; Zmeureanu, R. G.; Love, J. A.

2013-01-01T23:59:59.000Z

423

Big Eddy-Knight  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAboutScienceCareers Apply for a

424

Dynamic simulation of polyester mooring lines  

E-Print Network [OSTI]

A numerical scheme, known as CABLE3D, originally developed for the simulation of dynamics of steel chain-wire mooring lines is extended to allow for the large elongation in a mooring line, the dependence of the modulus on tension, and energy...

Kim, Min Suk

2004-09-30T23:59:59.000Z

425

CALIFORNIA ENERGY Large HVAC Building  

E-Print Network [OSTI]

CALIFORNIA ENERGY COMMISSION Large HVAC Building Survey Information Database of Buildings over 100 Design of Large Commercial HVAC Systems research project, one of six research elements in the Integrated Design of Large Commercial HVAC Systems Integrated Design of Small Commercial HVAC Systems Integrated

426

Model Validation with Hybrid Dynamic Simulation  

SciTech Connect (OSTI)

Abstract—Model validation has been one of the central topics in power engineering studies for years. As model validation aims at obtaining reasonable models to represent actual behavior of power system components, it has been essential to validate models against actual measurements or known benchmark behavior. System-wide model simulation results can be compared with actual recordings. However, it is difficult to construct a simulation case for a large power system such as the WECC system and to narrow down to problematic models in a large system. Hybrid dynamic simulation with its capability of injecting external signals into dynamic simulation enables rigorous comparison of measurements and simulation in a small subsystem of interest. This paper presents such a model validation methodology with hybrid dynamic simulation. Two application examples on generator and load model validation are presented to show the validity of this model validation methodology. This methodology is further extended for automatic model validation and dichotomous subsystem model validation. A few methods to define model quality indices have been proposed to quantify model error for model validation criteria development.

Huang, Zhenyu; Kosterev, Dmitry; Guttromson, Ross T.; Nguyen, Tony B.

2006-06-22T23:59:59.000Z

427

Simulation framework for intelligent transportation systems  

SciTech Connect (OSTI)

A simulation framework has been developed for a large-scale, comprehensive, scaleable simulation of an Intelligent Transportation System (ITS). The simulator is designed for running on parallel computers and distributed (networked) computer systems, but can run on standalone workstations for smaller simulations. The simulator currently models instrumented smart vehicles with in-vehicle navigation units capable of optimal route planning and Traffic Management Centers (TMC). The TMC has probe vehicle tracking capabilities (display position and attributes of instrumented vehicles), and can provide two-way interaction with traffic to provide advisories and link times. Both the in-vehicle navigation module and the TMC feature detailed graphical user interfaces to support human-factors studies. Realistic modeling of variations of the posted driving speed are based on human factors studies that take into consideration weather, road conditions, driver personality and behavior, and vehicle type. The prototype has been developed on a distributed system of networked UNIX computers but is designed to run on parallel computers, such as ANL`s IBM SP-2, for large-scale problems. A novel feature of the approach is that vehicles are represented by autonomous computer processes which exchange messages with other processes. The vehicles have a behavior model which governs route selection and driving behavior, and can react to external traffic events much like real vehicles. With this approach, the simulation is scaleable to take advantage of emerging massively parallel processor (MPP) systems.

Ewing, T.; Doss, E.; Hanebutte, U.; Tentner, A.

1996-10-01T23:59:59.000Z

428

Simulation of naturally fractured reservoirs using empirical transfer function  

E-Print Network [OSTI]

This research utilizes the imbibition experiments and X-ray tomography results for modeling fluid flow in naturally fractured reservoirs. Conventional dual porosity simulation requires large number of runs to quantify transfer function parameters...

Tellapaneni, Prasanna Kumar

2004-09-30T23:59:59.000Z

429

Timestep selection during streamline simulation via transverse flux correction  

E-Print Network [OSTI]

on their ability to take large timesteps with fewer pressure solutions within an IMPES formulation. However, unlike conventional finite-difference simulators, no clear guidelines are currently available for the choice of timestep for pressure and velocity updates...

Osako, Ichiro

2004-09-30T23:59:59.000Z

430

Stochastic Simulation Methods for Precipitation and Streamflow Time Series  

E-Print Network [OSTI]

One major acknowledged challenge in daily precipitation is the inability to model extreme events in the spectrum of events. These extreme events are rare but may cause large losses. How to realistically simulate extreme behavior of daily...

Li, Chao

2013-04-30T23:59:59.000Z

431

Ab initio molecular dynamics simulations of low energy recoil...  

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

of low energy recoil events in ceramics . Ab initio molecular dynamics simulations of low energy recoil events in ceramics . Abstract: The recent progress in the use of large-scale...

432

Scalable, probabilistic simulation in a distributed design environment  

E-Print Network [OSTI]

Integrated simulations have been used to predict and analyze the integrated behavior of large, complex product and technology systems throughout their design cycles. During the process of integration, uncertainties arise ...

Mao, Wei, Ph. D. Massachusetts Institute of Technology

2008-01-01T23:59:59.000Z

433

Accepted for publication in The Astrophysical Journal Preprint typeset using L ATEX style emulateapj v. 11/26/04 ON THE EVOLUTION OF THERMONUCLEAR FLAMES ON LARGE SCALES  

E-Print Network [OSTI]

The thermonuclear explosion of a massive white dwarf in a Type Ia supernova explosion is characterized by vastly disparate spatial and temporal scales. The extreme dynamic range inherent to the problem prevents the use of direct numerical simulation and forces modelers to resort to subgrid models to describe physical processes taking place on unresolved scales. We consider the evolution of a model thermonuclear flame in a constant gravitational field on a periodic domain. The gravitational acceleration is aligned with the overall direction of the flame propagation, making the flame surface subject to the Rayleigh-Taylor instability. The flame evolution is followed through an extended initial transient phase well into the steady-state regime. The properties of the evolution of flame surface are examined. We confirm the form of the governing equation of the evolution suggested by Khokhlov (1995). The mechanism of vorticity production and the interaction between vortices and the flame surface are discussed. Previously observed periodic behavior of the flame evolution is reproduced and is found to be caused by the turnover of the largest eddies. The characteristic timescales are found to be similar to the turnover time of these eddies. Relations between flame surface creation and destruction

Ju Zhang; O. E. Bronson Messer; Alexei M. Khokhlov; Tomasz Plewa

2006-01-01T23:59:59.000Z

434

COMPUMAGSYDNEY 2011, STATIC FIELDS AND QUASI-STATIC FIELDS (III), PA10.2, CMP305 1 Stochastic uncertainty quantification of the eddy current in human body by using  

E-Print Network [OSTI]

of the human body between different individuals, is a major problem in numerical dosimetry. Determining uncertainty quantification of the eddy current in human body by using polynomial chaos decomposition Roman be used to compute the electromagnetic fields induced in the human body by environmental extremely low

Boyer, Edmond

435

EddyRenaud-Lesam2013_Article -accede_document.php http://cemadoc.irstea.fr/exl-php/util/documents/accede_document.php 1 sur 10 03/02/2014 10:12  

E-Print Network [OSTI]

EddyRenaud-Lesam2013_Article - accede_document.php http://cemadoc.irstea.fr/exl-php/util/documents/accede_document.php - accede_document.php http://cemadoc.irstea.fr/exl-php/util/documents/accede_document.php 2 sur 10 03_Article - accede_document.php http://cemadoc.irstea.fr/exl-php/util/documents/accede_document.php 3 sur 10

Paris-Sud XI, Université de

436

Chimera Grids for Water Simulation R. Elliot English  

E-Print Network [OSTI]

Chimera Grids for Water Simulation R. Elliot English Stanford University Linhai Qiu Stanford propellers. Abstract We introduce a new method for large scale water simulation using Chimera grid embedding level set method in order to adapt it to Chimera grids including particle treatment across grid

Fedkiw, Ron

437

Collaborative Monitoring and Analysis for Simulation Scientist  

SciTech Connect (OSTI)

Collaboratively monitoring and analyzing large scale simulations from petascale computers is an important area of research and development within the scientific community. This paper addresses these issues when teams of colleagues from different research areas work together to help understand the complex data generated from these simulations. In particular, we address the issues when geographically diverse teams of disparate researchers work together to understand the complex science being simulation on high performance computers. Most application scientists want to focus on the sciences and spend a minimum amount of time learning new tools or adopting new techniques to monitor and analyze their simulation data. The challenge eSimMon, of our web-based system is to decrease or eliminate some of the hurdles on the scientists path to scientific discovery, and allow these collaborations to flourish.

Tchoua, Roselyne B [ORNL] [ORNL; Klasky, Scott A [ORNL] [ORNL; Podhorszki, Norbert [ORNL] [ORNL; Khan, Ayla Y [ORNL] [ORNL; Mouallem, P. A. [North Carolina State University] [North Carolina State University; Vouk, Mladen [North Carolina State University] [North Carolina State University

2010-01-01T23:59:59.000Z

438

Analysis of turbulent transport and mixing in transitional Rayleigh/Taylor unstable flow using direct numerical simulation data  

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

Data from a 1152X760X1280 direct numerical simulation (DNS) [N. J. Mueschke and O. Schilling, Phys. Fluids 21, 014106 (2009)] of a transitional Rayleigh-Taylor mixing layer modeled after a small Atwood number water channel experiment is used to comprehensively investigate the structure of mean and turbulent transport and mixing. The simulation had physical parameters and initial conditions approximating those in the experiment. The budgets of the mean vertical momentum, heavy-fluid mass fraction, turbulent kinetic energy, turbulent kinetic energy dissipation rate, heavy-fluid mass fraction variance, and heavy-fluid mass fraction variance dissipation rate equations are constructed using Reynolds averaging applied to the DNS data. The relative importance of mean and turbulent production, turbulent dissipation and destruction, and turbulent transport are investigated as a function of Reynolds number and across the mixing layer to provide insight into the flow dynamics not presently available from experiments. The analysis of the budgets supports the assumption for small Atwood number, Rayleigh/Taylor driven flows that the principal transport mechanisms are buoyancy production, turbulent production, turbulent dissipation, and turbulent diffusion (shear and mean field production are negligible). As the Reynolds number increases, the turbulent production in the turbulent kinetic energy dissipation rate equation becomes the dominant production term, while the buoyancy production plateaus. Distinctions between momentum and scalar transport are also noted, where the turbulent kinetic energy and its dissipation rate both grow in time and are peaked near the center plane of the mixing layer, while the heavy-fluid mass fraction variance and its dissipation rate initially grow and then begin to decrease as mixing progresses and reduces density fluctuations. All terms in the transport equations generally grow or decay, with no qualitative change in their profile, except for the pressure flux contribution to the total turbulent kinetic energy flux, which changes sign early in time (a countergradient effect). The production-to-dissipation ratios corresponding to the turbulent kinetic energy and heavy-fluid mass fraction variance are large and vary strongly at small evolution times, decrease with time, and nearly asymptote as the flow enters a self-similar regime. The late-time turbulent kinetic energy production-to-dissipation ratio is larger than observed in shear-driven turbulent flows. The order of magnitude estimates of the terms in the transport equations are shown to be consistent with the DNS at late-time, and also confirms both the dominant terms and their evolutionary behavior. These results are useful for identifying the dynamically important terms requiring closure, and assessing the accuracy of the predictions of Reynolds-averaged Navier-Stokes and large-eddy simulation models of turbulent transport and mixing in transitional Rayleigh-Taylor instability-generated flow.

Schilling, Oleg [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Mueschke, Nicholas J. [Texas A and M Univ., College Station, TX (United States)

2010-10-18T23:59:59.000Z

439

Investigating Output Accuracy for a Discrete Event Simulation Model and an Agent Based Simulation Model  

E-Print Network [OSTI]

In this paper, we investigate output accuracy for a Discrete Event Simulation (DES) model and Agent Based Simulation (ABS) model. The purpose of this investigation is to find out which of these simulation techniques is the best one for modelling human reactive behaviour in the retail sector. In order to study the output accuracy in both models, we have carried out a validation experiment in which we compared the results from our simulation models to the performance of a real system. Our experiment was carried out using a large UK department store as a case study. We had to determine an efficient implementation of management policy in the store's fitting room using DES and ABS. Overall, we have found that both simulation models were a good representation of the real system when modelling human reactive behaviour.

Majid, Mazlina Abdul; Siebers, Peer-Olaf

2010-01-01T23:59:59.000Z

440

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. ???, XXXX, DOI:10.1029/, An EddyResolving Ocean Model for the Pacific1  

E-Print Network [OSTI]

for the Pacific1 Ocean: Part 1: Deep Convection and Its Relation to2 SST Anomalies3 A. B. Kara, E. J. Metzger, H­latitudes) HYbrid Coordinate Ocean Model (HYCOM),10 configured for the Pacific Ocean (north of 20 S) is used to satellite­based products over the Pacific22 Ocean. HYCOM simulation with no assimilation of any SST gives

Miami, University of

Note: This page contains sample records for the topic "large eddy simulation" 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

Simulating Microbial Community Patterning Using Biocellion  

SciTech Connect (OSTI)

Mathematical modeling and computer simulation are important tools for understanding complex interactions between cells and their biotic and abiotic environment: similarities and differences between modeled and observed behavior provide the basis for hypothesis forma- tion. Momeni et al. [5] investigated pattern formation in communities of yeast strains engaging in different types of ecological interactions, comparing the predictions of mathematical modeling and simulation to actual patterns observed in wet-lab experiments. However, simu- lations of millions of cells in a three-dimensional community are ex- tremely time-consuming. One simulation run in MATLAB may take a week or longer, inhibiting exploration of the vast space of parameter combinations and assumptions. Improving the speed, scale, and accu- racy of such simulations facilitates hypothesis formation and expedites discovery. Biocellion is a high performance software framework for ac- celerating discrete agent-based simulation of biological systems with millions to trillions of cells. Simulations of comparable scale and accu- racy to those taking a week of computer time using MATLAB require just hours using Biocellion on a multicore workstation. Biocellion fur- ther accelerates large scale, high resolution simulations using cluster computers by partitioning the work to run on multiple compute nodes. Biocellion targets computational biologists who have mathematical modeling backgrounds and basic C++ programming skills. This chap- ter describes the necessary steps to adapt the original Momeni et al.'s model to the Biocellion framework as a case study.

Kang, Seung-Hwa; Kahan, Simon H.; Momeni, Babak

2014-04-17T23:59:59.000Z

442

Simulations of Solar Active  

E-Print Network [OSTI]

sunspot fine structure as consequence of magneto- convective energy transport in umbra and penumbra. Large

443

Large Scale Energy Storage: From Nanomaterials to Large Systems  

E-Print Network [OSTI]

Large Scale Energy Storage: From Nanomaterials to Large Systems Wednesday October 26, 2011, Babbio energy storage devices. Specifically, this talk discusses 1) the challenges for grid scale of emergent technologies with ultralow costs on new energy storage materials and mechanisms. Dr. Jun Liu

Fisher, Frank

444

LARGE-APERTURE D- ACCELERATORS  

E-Print Network [OSTI]

Vignetted current profile at accelerator entrance aperture 'LARGE-APERTURE D" ACCELERATORS* 0. A. Anderson" " Lawrencen i a 9-1720 Abstract Accelerator designs are described for

Anderson, O.A.

2010-01-01T23:59:59.000Z

445

QUENCHES IN LARGE SUPERCONDUCTING MAGNETS  

E-Print Network [OSTI]

QUENCHES IN LARGE SUPERCONDUCTING MAGNETS. P. H. Eberhard,Study of an Unprotected Superconducting Coil Going Normal,"Method for Testing Superconducting Magnets," LBL Physics

Eberhard, P.H.

2010-01-01T23:59:59.000Z

446

Large Magnetization at Carbon Surfaces  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and Interfaces Sample6, 2011 CERN 73-11Large area avalancheLargeLargeLarge

447

Computational Geosciences 1 (1997) 271288 271 Pulsing of multiple nutrients as a strategy to achieve large  

E-Print Network [OSTI]

to achieve large biologically active zones during in situ carbon tetrachloride remediation Marlee E kinetic expressions describing microbial growth and carbon tetrachloride degradation under denitrifying significant biomass growth and contaminant destruction. Keywords: bioremediation, numerical simulation, carbon

Clement, Prabhakar

448

The CLAS12 large area RICH detector  

SciTech Connect (OSTI)

A large area RICH detector is being designed for the CLAS12 spectrometer as part of the 12 GeV upgrade program of the Jefferson Lab Experimental Hall-B. This detector is intended to provide excellent hadron identification from 3 GeV/c up to momenta exceeding 8 GeV/c and to be able to work at the very high design luminosity-up to 1035 cm2 s?1. Detailed feasibility studies are presented for two types of radiators, aerogel and liquid C6F14 freon, in conjunction with a highly segmented light detector in the visible wavelength range. The basic parameters of the RICH are outlined and the resulting performances, as defined by preliminary simulation studies, are reported.

M. Contalbrigo, E. Cisbani, P. Rossi

2011-05-01T23:59:59.000Z

449

Whole Building Energy Simulation  

Broader source: Energy.gov [DOE]

Whole building energy simulation, also referred to as energy modeling, can and should be incorporated early during project planning to provide energy impact feedback for which design considerations...

450

Simulated progress in double-beta decay  

SciTech Connect (OSTI)

A Monte Carlo code has been developed to accurately simulate double-beta decay measurements. Coincident gamma rays, beta spectra, and angular correlations have been added to adequately simulate a complete {sup 100}Mo nuclear decay and provide corrections to experimentally determined detector efficiencies. This code has been used to strip certain low-background spectra obtained in the Homestake gold mine in Lead, SD, for the purpose of extremely sensitive materials assay for the construction of new, large, enriched germanium detectors. Assays as low as 9 {mu}Bq/g of {sup 210}Pb in lead shielding were obtained.

Miley, H.S.; Arthur, R.J. [Pacific Northwest Lab., Richland, WA (United States); Avignone, F.T. [South Carolina Univ., Columbia, SC (United States)] [and others

1993-09-01T23:59:59.000Z

451

Physics results from dynamical overlap fermion simulations  

E-Print Network [OSTI]

I summarize the physics results obtained from large-scale dynamical overlap fermion simulations by the JLQCD and TWQCD collaborations. The numerical simulations are performed at a fixed global topological sector; the physics results in the theta-vacuum is reconstructed by correcting the finite volume effect, for which the measurement of the topological susceptibility is crucial. Physics applications we studied so far include a calculation of chiral condensate, pion mass, decay constant, form factors, as well as (vector and axial-vector) vacuum polarization functions and nucleon sigma term.

Shoji Hashimoto

2008-11-08T23:59:59.000Z

452

Issues in Numerical Simulation of Fire Suppression  

SciTech Connect (OSTI)

This paper outlines general physical and computational issues associated with performing numerical simulation of fire suppression. Fire suppression encompasses a broad range of chemistry and physics over a large range of time and length scales. The authors discuss the dominant physical/chemical processes important to fire suppression that must be captured by a fire suppression model to be of engineering usefulness. First-principles solutions are not possible due to computational limitations, even with the new generation of tera-flop computers. A basic strategy combining computational fluid dynamics (CFD) simulation techniques with sub-grid model approximations for processes that have length scales unresolvable by gridding is presented.

Tieszen, S.R.; Lopez, A.R.

1999-04-12T23:59:59.000Z

453

Simulation Supported Decision Making  

E-Print Network [OSTI]

.S. Navy Nuclear Program · Decades of dynamic operations of hundreds of nuclear power plants withoutSimulation Supported Decision Making Gene Allen Naval Surface Warfare Center Carderock Division SI: TO PASS ON WHAT I KNOW on SIMULATION · CAREER FOCUS: HOW TO USE COMPUTERS TO DO HELP MAKE BETTER DECISIONS

454

Radiation detector spectrum simulator  

DOE Patents [OSTI]

A small battery operated nuclear spectrum simulator having a noise source nerates pulses with a Gaussian distribution of amplitudes. A switched dc bias circuit cooperating therewith generates several nominal amplitudes of such pulses and a spectral distribution of pulses that closely simulates the spectrum produced by a radiation source such as Americium 241.

Wolf, Michael A. (Los Alamos, NM); Crowell, John M. (Los Alamos, NM)

1987-01-01T23:59:59.000Z

455

Radiation detector spectrum simulator  

DOE Patents [OSTI]

A small battery operated nuclear spectrum simulator having a noise source generates pulses with a Gaussian distribution of amplitudes. A switched dc bias circuit cooperating therewith to generate several nominal amplitudes of such pulses and a spectral distribution of pulses that closely simulates the spectrum produced by a radiation source such as Americium 241.

Wolf, M.A.; Crowell, J.M.

1985-04-09T23:59:59.000Z

456

Large Magnetization at Carbon Surfaces  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and Interfaces Sample6, 2011 CERN 73-11Large area avalancheLargeLarge

457

Large Magnetization at Carbon Surfaces  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and Interfaces Sample6, 2011 CERN 73-11Large areaLarge Magnetization atLarge

458

A Prototype Two-Decade Fully-Coupled Fine-Resolution CCSM Simulation  

SciTech Connect (OSTI)

A fully coupled global simulation using the Community Climate System Model (CCSM) was configured using grid resolutions of 0.1{sup o} for the ocean and sea-ice, and 0.25{sup o} for the atmosphere and land, and was run under present-day greenhouse gas conditions for 20 years. It represents one of the first efforts to simulate the planetary system at such high horizontal resolution. The climatology of the circulation of the atmosphere and the upper ocean were compared with observational data and reanalysis products to identify persistent mean climate biases. Intensified and contracted polar vortices, and too cold sea surface temperatures (SSTs) in the subpolar and mid-latitude Northern Hemisphere were the dominant biases produced by the model. Intense category 4 cyclones formed spontaneously in the tropical North Pacific. A case study of the ocean response to one such event shows the realistic formation of a cold SST wake, mixed layer deepening, and warming below the mixed layer. Too many tropical cyclones formed in the North Pacific however, due to too high SSTs in the tropical eastern Pacific. In the North Atlantic anomalously low SSTs lead to a dearth of hurricanes. Agulhas eddy pathways are more realistic than in equivalent stand-alone ocean simulations forced with atmospheric reanalysis.

McClean, Julie L. [Scripps Institute of Oceanography; Bader, David C [ORNL; Bryan, Frank O. [National Center for Atmospheric Research (NCAR); Maltrud, Matthew E. [Los Alamos National Laboratory (LANL); Dennis, John [National Center for Atmospheric Research (NCAR); Mirin, Arthur A. [Lawrence Livermore National Laboratory (LLNL); Jones, Philip W [Los Alamos National Laboratory (LANL); Vertenstein, Mariana [National Center for Atmospheric Research (NCAR); Ivanova, Detelina P. [Lawrence Livermore National Laboratory (LLNL); Kim, Yoo Yin [Scripps Institute of Oceanography; Boyle, James S. [Lawrence Livermore National Laboratory (LLNL); Jacob, Robert L. [Argonne National Laboratory (ANL); Norton, Nancy [IBM and National Center for Atmospheric Research; Craig, Anthony [National Center for Atmospheric Research (NCAR); Worley, Patrick H [ORNL

2011-01-01T23:59:59.000Z

459

UNIVERSITY OF SOUTHERN CALIFORNIA CSCI 653 (High Performance Computing and Simulations) : Fall 2013  

E-Print Network [OSTI]

UNIVERSITY OF SOUTHERN CALIFORNIA CSCI 653 (High Performance Computing and Simulations) : Fall 2013 Performance Computing and Simulations). My PhD work is in the area of resiliency for future Exascale High. 2 DESCRIPTION OF AN HPCS APPLICATION Simulation of Large Scale High Performance Computing System

Southern California, University of

460

Agent-based Simulation of Group Learning Maartje Spoelstra1,2  

E-Print Network [OSTI]

Agent-based Simulation of Group Learning Maartje Spoelstra1,2 and Elizabeth Sklar3 1 Dept of simulated learners that model the behaviour of humans acting in various learning environments, with the aims of the present simulation on the large body of existing research on "group learning" that has been conducted

Sklar, Elizabeth

Note: This page contains sample records for the topic "large eddy simulation" 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

Advanced Oil Recovery Technologies for Improved Recovery from Slope Basin Clastic Reservoirs, Nash Draw Brushy Canyon Pool, Eddy County, NM  

SciTech Connect (OSTI)

Advanced reservoir characterization techniques are being used at the Nash Draw Brushy Canyon Pool project to develop reservoir management strategies for optimizing oil recovery from this Delaware reservoir. The reservoir characterization, geologic modeling, 3-D seismic interpretation, and simulation studies have provided a detailed model of the Brushy Canyon zones. This model was used to predict the success of different reservoir management scenarios and to aid in determining the most favorable combination of targeted drilling, pressure maintenance, well stimulation, and well spacing to improve recovery from this reservoir.

Murphy, M.B.

1999-02-01T23:59:59.000Z

462

Large Sheet Process Consolidation Project  

E-Print Network [OSTI]

The purpose of this project is to reduce labor costs through the consolidation of large sheet processes into the Beta and Alpha manufacturing plants. The consolidation of equipment and departments will allow for the reduction of indirect labor...

Johnson, Keith

2005-12-16T23:59:59.000Z

463

The Description of Large Systems  

E-Print Network [OSTI]

In this paper we discuss the problems associated with the description and manipulation of large systems when their sources are not maintained as single fields. We show why and how tools that address these issues, such ...

Pitman, Kent

1984-09-01T23:59:59.000Z

464

FEA Simulations of Magnets with Grain Oriented Steel  

SciTech Connect (OSTI)

One of the potential successors of the Large Hadron Collider is a Muon Col- lider. Muons are short-lived particles, which therefore require fast acceleration. One potential avenue is a very fast cycling cyclotron, where the bending is sup- plied by a combination of fixed-field superconducting magnets and fast ramping normal conducting iron-cored coils. Due to the high ramping rate (around 1 kHz) eddy current and hysteresis losses are a concern. One way to overcome these is by using grain-oriented soft-iron, which promises superior magnetic properties in the direction of the grains. This note summarizes efforts to include the anisotropic material properties of grain-oriented steel in finite element analysis to predict the behaviour of the dipole magnets for this accelerator. It was found that including anisotropic material properties has a detrimental effect on model convergence. During this study it was not possible to include grain oriented steel with an accuracy necessary to study the field quality of a dipole magnet.

Witte H.

2012-08-06T23:59:59.000Z

465

Generation of large-scale winds in horizontally anisotropic convection  

E-Print Network [OSTI]

We simulate three-dimensional, horizontally periodic Rayleigh-B\\'enard convection between free-slip horizontal plates, rotating about a horizontal axis. When both the temperature difference between the plates and the rotation rate are sufficiently large, a strong horizontal wind is generated that is perpendicular to both the rotation vector and the gravity vector. The wind is turbulent, large-scale, and vertically sheared. Horizontal anisotropy, engendered here by rotation, appears necessary for such wind generation. Most of the kinetic energy of the flow resides in the wind, and the vertical turbulent heat flux is much lower on average than when there is no wind.

von Hardenberg, J; Provenzale, A; Spiegel, E A

2015-01-01T23:59:59.000Z

466

Duct thermal performance models for large commercial buildings  

SciTech Connect (OSTI)

Despite the potential for significant energy savings by reducing duct leakage or other thermal losses from duct systems in large commercial buildings, California Title 24 has no provisions to credit energy-efficient duct systems in these buildings. A substantial reason is the lack of readily available simulation tools to demonstrate the energy-saving benefits associated with efficient duct systems in large commercial buildings. The overall goal of the Efficient Distribution Systems (EDS) project within the PIER High Performance Commercial Building Systems Program is to bridge the gaps in current duct thermal performance modeling capabilities, and to expand our understanding of duct thermal performance in California large commercial buildings. As steps toward this goal, our strategy in the EDS project involves two parts: (1) developing a whole-building energy simulation approach for analyzing duct thermal performance in large commercial buildings, and (2) using the tool to identify the energy impacts of duct leakage in California large commercial buildings, in support of future recommendations to address duct performance in the Title 24 Energy Efficiency Standards for Nonresidential Buildings. The specific technical objectives for the EDS project were to: (1) Identify a near-term whole-building energy simulation approach that can be used in the impacts analysis task of this project (see Objective 3), with little or no modification. A secondary objective is to recommend how to proceed with long-term development of an improved compliance tool for Title 24 that addresses duct thermal performance. (2) Develop an Alternative Calculation Method (ACM) change proposal to include a new metric for thermal distribution system efficiency in the reporting requirements for the 2005 Title 24 Standards. The metric will facilitate future comparisons of different system types using a common ''yardstick''. (3) Using the selected near-term simulation approach, assess the impacts of duct system improvements in California large commercial buildings, over a range of building vintages and climates. This assessment will provide a solid foundation for future efforts that address the energy efficiency of large commercial duct systems in Title 24. This report describes our work to address Objective 1, which includes a review of past modeling efforts related to duct thermal performance, and recommends near- and long-term modeling approaches for analyzing duct thermal performance in large commercial buildings.

Wray, Craig P.

2003-10-01T23:59:59.000Z

467

Energy-Aware Routing in Sensor Networks: A Large Systems Approach  

E-Print Network [OSTI]

Energy-Aware Routing in Sensor Networks: A Large Systems Approach Longbi Lin, Ness B. Shroff, and R capacity. Index Terms-- Energy-Aware Routing, Sensor Network, Large System, Mathematical Programming/Optimization, Simulations I. INTRODUCTION Energy-aware routing problem in sensor networks has received significant attention

Paris-Sud XI, Université de

468

Wave-Based Sound Propagation in Large Open Scenes using an Equivalent Source Formulation  

E-Print Network [OSTI]

Wave-Based Sound Propagation in Large Open Scenes using an Equivalent Source Formulation RAVISH We present a novel approach for wave-based sound propagation suitable for large, open spaces spanning or simulation systems, present a significant chal- lenge for interactive, wave-based sound propagation

North Carolina at Chapel Hill, University of

469

A Topological Framework for the Interactive Exploration of Large Scale Turbulent Combustion  

E-Print Network [OSTI]

A Topological Framework for the Interactive Exploration of Large Scale Turbulent Combustion Peer a new topological framework for the analysis of large scale, time-varying, turbulent combustion consumption thresh- olds for an entire time-dependent combustion simulation. By computing augmented merge

Knowles, David William

470

Ris-R-Report Improved design for large wind turbine blades  

E-Print Network [OSTI]

for large wind turbine blades of fibre composites (Phase 4) - Summary report Division: 1 Materials Research of wind turbine blade involving geometric and material instabilities 30 5.2 Simulation of crack growthRisø-R-Report Improved design for large wind turbine blades of fibre composites (Phase 4) - Summary

471

Argonne simulation framework for intelligent transportation systems  

SciTech Connect (OSTI)

A simulation framework has been developed which defines a high-level architecture for a large-scale, comprehensive, scalable simulation of an Intelligent Transportation System (ITS). The simulator is designed to run on parallel computers and distributed (networked) computer systems; however, a version for a stand alone workstation is also available. The ITS simulator includes an Expert Driver Model (EDM) of instrumented ``smart`` vehicles with in-vehicle navigation units. The EDM is capable of performing optimal route planning and communicating with Traffic Management Centers (TMC). A dynamic road map data base is sued for optimum route planning, where the data is updated periodically to reflect any changes in road or weather conditions. The TMC has probe vehicle tracking capabilities (display position and attributes of instrumented vehicles), and can provide 2-way interaction with traffic to provide advisories and link times. Both the in-vehicle navigation module and the TMC feature detailed graphical user interfaces that includes human-factors studies to support safety and operational research. Realistic modeling of variations of the posted driving speed are based on human factor studies that take into consideration weather, road conditions, driver`s personality and behavior and vehicle type. The simulator has been developed on a distributed system of networked UNIX computers, but is designed to run on ANL`s IBM SP-X parallel computer system for large scale problems. A novel feature of the developed simulator is that vehicles will be represented by autonomous computer processes, each with a behavior model which performs independent route selection and reacts to external traffic events much like real vehicles. Vehicle processes interact with each other and with ITS components by exchanging messages. With this approach, one will be able to take advantage of emerging massively parallel processor (MPP) systems.

Ewing, T.; Doss, E.; Hanebutte, U.; Canfield, T.; Brown-VanHoozer, A.; Tentner, A.

1996-04-01T23:59:59.000Z

472

Xyce parallel electronic simulator : users' guide.  

SciTech Connect (OSTI)

This manual describes the use of the Xyce Parallel Electronic Simulator. Xyce has been designed as a SPICE-compatible, high-performance analog circuit simulator, and has been written to support the simulation needs of the Sandia National Laboratories electrical designers. This development has focused on improving capability over the current state-of-the-art in the following areas: (1) Capability to solve extremely large circuit problems by supporting large-scale parallel computing platforms (up to thousands of processors). Note that this includes support for most popular parallel and serial computers; (2) Improved performance for all numerical kernels (e.g., time integrator, nonlinear and linear solvers) through state-of-the-art algorithms and novel techniques. (3) Device models which are specifically tailored to meet Sandia's needs, including some radiation-aware devices (for Sandia users only); and (4) Object-oriented code design and implementation using modern coding practices that ensure that the Xyce Parallel Electronic Simulator will be maintainable and extensible far into the future. Xyce is a parallel code in the most general sense of the phrase - a message passing parallel implementation - which allows it to run efficiently on the widest possible number of computing platforms. These include serial, shared-memory and distributed-memory parallel as well as heterogeneous platforms. Careful attention has been paid to the specific nature of circuit-simulation problems to ensure that optimal parallel efficiency is achieved as the number of processors grows. The development of Xyce provides a platform for computational research and development aimed specifically at the needs of the Laboratory. With Xyce, Sandia has an 'in-house' capability with which both new electrical (e.g., device model development) and algorithmic (e.g., faster time-integration methods, parallel solver algorithms) research and development can be performed. As a result, Xyce is a unique electrical simulation capability, designed to meet the unique needs of the laboratory.

Mei, Ting; Rankin, Eric Lamont; Thornquist, Heidi K.; Santarelli, Keith R.; Fixel, Deborah A.; Coffey, Todd Stirling; Russo, Thomas V.; Schiek, Richard Louis; Warrender, Christina E.; Keiter, Eric Richard; Pawlowski, Roger Patrick

2011-05-01T23:59:59.000Z

473

Phenomenology from 100 large lattices  

E-Print Network [OSTI]

We present a status report on simulations being done on $32^3 \\times 64$ lattices at $\\beta = 6.0$ using quenched Wilson fermions. Phenomenologically relevant results for the spectrum, decay constants, the kaon B-parameter $B_K$, $B_7$, $B_8$, semi-leptonic and $B\\to K^* \\gamma$ form factors are given based on a statistical sample of 100 configurations.

Tanmoy Bhattacharya; Rajan Gupta

1995-01-15T23:59:59.000Z

474

Large scale quantum mechanical enzymology  

E-Print Network [OSTI]

conventional QM methods but, due to the computational costs, as will be discussed later in this dissertation, the system sizes accessible with these approaches do not reach the requirements for studying biomolecular systems. A particularly successful brand... imaging allow certain structural information to be extracted, such as interatomic distances and torsion angles. In the all important quest for experimental agreement, it would be all too easy to assert that if simulations generate the same result...

Lever, Greg

2014-10-07T23:59:59.000Z

475

Theory Modeling and Simulation  

SciTech Connect (OSTI)

Los Alamos has a long history in theory, modeling and simulation. We focus on multidisciplinary teams that tackle complex problems. Theory, modeling and simulation are tools to solve problems just like an NMR spectrometer, a gas chromatograph or an electron microscope. Problems should be used to define the theoretical tools needed and not the other way around. Best results occur when theory and experiments are working together in a team.

Shlachter, Jack [Los Alamos National Laboratory

2012-08-23T23:59:59.000Z

476

Xyce parallel electronic simulator.  

SciTech Connect (OSTI)

This document is a reference guide to the Xyce Parallel Electronic Simulator, and is a companion document to the Xyce Users' Guide. The focus of this document is (to the extent possible) exhaustively list device parameters, solver options, parser options, and other usage details of Xyce. This document is not intended to be a tutorial. Users who are new to circuit simulation are better served by the Xyce Users' Guide.

Keiter, Eric Richard; Mei, Ting; Russo, Thomas V.; Rankin, Eric Lamont; Schiek, Richard Louis; Thornquist, Heidi K.; Fixel, Deborah A.; Coffey, Todd Stirling; Pawlowski, Roger Patrick; Santarelli, Keith R.

2010-05-01T23:59:59.000Z

477

Large Magnetization at Carbon Surfaces  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and Interfaces Sample6, 2011 CERN 73-11Large area avalancheLarge

478

Large Magnetization at Carbon Surfaces  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and Interfaces Sample6, 2011 CERN 73-11Large areaLarge Magnetization at

479

Large Magnetization at Carbon Surfaces  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-SeriesFlickrinformationPostdocs space CombinedValues shown forShadeandLargeLarge

480

National Geo-Database for Biofuel Simulations and Regional Analysis  

SciTech Connect (OSTI)

The goal of this project undertaken by GLBRC (Great Lakes Bioenergy Research Center) Area 4 (Sustainability) modelers is to develop a national capability to model feedstock supply, ethanol production, and biogeochemical impacts of cellulosic biofuels. The results of this project contribute to sustainability goals of the GLBRC; i.e. to contribute to developing a sustainable bioenergy economy: one that is profitable to farmers and refiners, acceptable to society, and environmentally sound. A sustainable bioenergy economy will also contribute, in a fundamental way, to meeting national objectives on energy security and climate mitigation. The specific objectives of this study are to: (1) develop a spatially explicit national geodatabase for conducting biofuel simulation studies; (2) model biomass productivity and associated environmental impacts of annual cellulosic feedstocks; (3) simulate production of perennial biomass feedstocks grown on marginal lands; and (4) locate possible sites for the establishment of cellulosic ethanol biorefineries. To address the first objective, we developed SENGBEM (Spatially Explicit National Geodatabase for Biofuel and Environmental Modeling), a 60-m resolution geodatabase of the conterminous USA containing data on: (1) climate, (2) soils, (3) topography, (4) hydrography, (5) land cover/ land use (LCLU), and (6) ancillary data (e.g., road networks, federal and state lands, national and state parks, etc.). A unique feature of SENGBEM is its 2008-2010 crop rotation data, a crucially important component for simulating productivity and biogeochemical cycles as well as land-use changes associated with biofuel cropping. We used the EPIC (Environmental Policy Integrated Climate) model to simulate biomass productivity and environmental impacts of annual and perennial cellulosic feedstocks across much of the USA on both croplands and marginal lands. We used data from LTER and eddy-covariance experiments within the study region to test the performance of EPIC and, when necessary, improve its parameterization. We investigated three scenarios. In the first, we simulated a historical (current) baseline scenario composed mainly of corn-, soybean-, and wheat-based rotations as grown existing croplands east of the Rocky Mountains in 30 states. In the second scenario, we simulated a modified baseline in which we harvested corn and wheat residues to supply feedstocks to potential cellulosic ethanol biorefineries distributed within the study area. In the third scenario, we simulated the productivity of perennial cropping systems such as switchgrass or perennial mixtures grown on either marginal or Conservation Reserve Program (CRP) lands. In all cases we evaluated the environmental impacts (e.g., soil carbon changes, soil erosion, nitrate leaching, etc.) associated with the practices. In summary, we have reported on the development of a spatially explicit national geodatabase to conduct biofuel simulation studies and provided initial simulation results on the potential of annual and perennial cropping systems to serve as feedstocks for the production of cellulosic ethanol. To accomplish this, we have employed sophisticated spatial analysis methods in combination with the process-based biogeochemical model EPIC. This work provided the opportunity to test the hypothesis that marginal lands can serve as sources of cellulosic feedstocks and thus contribute to avoid potential conflicts between bioenergy and food production systems. This work, we believe, opens the door for further analysis on the characteristics of cellulosic feedstocks as major contributors to the development of a sustainable bioenergy economy.

Izaurralde, Roberto C.; Zhang, Xuesong; Sahajpal, Ritvik; Manowitz, David H.

2012-04-01T23:59:59.000Z

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481

A NEW GENERATION CHEMICAL FLOODING SIMULATOR  

SciTech Connect (OSTI)

The premise of this research is that a general-purpose reservoir simulator for several improved oil recovery processes can and should be developed so that high-resolution simulations of a variety of very large and difficult problems can be achieved using state-of-the-art algorithms and computers. Such a simulator is not currently available to the industry. The goal of this proposed research is to develop a new-generation chemical flooding simulator that is capable of efficiently and accurately simulating oil reservoirs with at least a million gridblocks in less than one day on massively parallel computers. Task 1 is the formulation and development of solution scheme, Task 2 is the implementation of the chemical module, and Task 3 is validation and application. We have made significant progress on all three tasks and we are on schedule on both technical and budget. In this report, we will detail our progress on Tasks 1 through 3 for the first six months of the second year of the project.

Gary A. Pope; Kamy Sepehrnoori; Mojdeh Delshad

2003-04-01T23:59:59.000Z

482

On spurious behavior of CFD simulations  

SciTech Connect (OSTI)

Spurious behavior in underresolved grids and/or semi-implicit temporal discretizations for four computational fluid dynamics (CFD) simulations are studied. The numerical simulations consist of (a) a 1-D chemically relaxed nonequilibrium model, (b) the direct numerical simulation (DNS) of 2-D incompressible flow over a backward facing step, (c) a loosely-coupled approach for a 2-D fluid-structure interaction, and (d) a 3-D compressible unsteady flow simulation of vortex breakdown in delta wings. Using knowledge from dynamical systems theory, various types of spurious behaviors that are numerical artifacts were systematically identified. These studies revealed the various possible dangers of misinterpreting numerical simulation of realistic complex flows that are constrained by the available computing power. In large scale computations underresolved grids, semi-implicit procedures, loosely-coupled implicit procedures, and insufficiently long time integration in DNS are most often unavoidable. Consequently, care must be taken in both computation and in interpretation of the numerical data. The results presented confirm the important role that dynamical systems theory can play in the understanding of the nonlinear behavior of numerical algorithms and in aiding the identification of the sources of numerical uncertainties in CFD.

Yee, H.C. [National Aeronautics and Space Administration, Moffett Field, CA (United States). Ames Research Center; Torczynski, J.R. [Sandia National Labs., Albuquerque, NM (United States); Morton, S.A.; Visbal, M.R. [Wright Lab., Wright-Patterson AFB, OH (United States); Sweby, P.K. [Univ. of Reading (United Kingdom)

1997-05-01T23:59:59.000Z

483

Iterative methods for the solution of very large complex symmetric linear systems of equations in electrodynamics  

SciTech Connect (OSTI)

In the field of computational electrodynamics the discretization of Maxwell`s equations using the Finite Integration Theory (FIT) yields very large, sparse, complex symmetric linear systems of equations. For this class of complex non-Hermitian systems a number of conjugate gradient-type algorithms is considered. The complex version of the biconjugate gradient (BiCG) method by Jacobs can be extended to a whole class of methods for complex-symmetric algorithms SCBiCG(T, n), which only require one matrix vector multiplication per iteration step. In this class the well-known conjugate orthogonal conjugate gradient (COCG) method for complex-symmetric systems corresponds to the case n = 0. The case n = 1 yields the BiCGCR method which corresponds to the conjugate residual algorithm for the real-valued case. These methods in combination with a minimal residual smoothing process are applied separately to practical 3D electro-quasistatical and eddy-current problems in electrodynamics. The practical performance of the SCBiCG methods is compared with other methods such as QMR and TFQMR.

Clemens, M.; Weiland, T. [Technische Hochschule Darmstadt (Germany)

1996-12-31T23:59:59.000Z

484

Communication Simulations for Power System Applications  

SciTech Connect (OSTI)

New smart grid technologies and concepts, such as dynamic pricing, demand response, dynamic state estimation, and wide area monitoring, protection, and control, are expected to require considerable communication resources. As the cost of retrofit can be high, future power grids will require the integration of high-speed, secure connections with legacy communication systems, while still providing adequate system control and security. While considerable work has been performed to create co-simulators for the power domain with load models and market operations, limited work has been performed in integrating communications directly into a power domain solver. The simulation of communication and power systems will become more important as the two systems become more inter-related. This paper will discuss ongoing work at Pacific Northwest National Laboratory to create a flexible, high-speed power and communication system co-simulator for smart grid applications. The framework for the software will be described, including architecture considerations for modular, high performance computing and large-scale scalability (serialization, load balancing, partitioning, cross-platform support, etc.). The current simulator supports the ns-3 (telecommunications) and GridLAB-D (distribution systems) simulators. Ongoing and future work will be described, including planned future expansions for a traditional transmission solver. A test case using the co-simulator, utilizing a transactive demand response system created for the Olympic Peninsula and AEP gridSMART demonstrations, requiring two-way communication between distributed and centralized market devices, will be used to demonstrate the value and intended purpose of the co-simulation environment.

Fuller, Jason C.; Ciraci, Selim; Daily, Jeffrey A.; Fisher, Andrew R.; Hauer, Matthew L.

2013-05-29T23:59:59.000Z

485

Riddell Revolution Speed Adult Large  

E-Print Network [OSTI]

Available: Adult Football Helmet Detailed Ratings May 2012 Riddell 360 Sample 1 2 3 Size Adult Large Adult.237 0.239 Overall STAR 0.239 Best Available: A total of 15 adult football helmet models that have been values. Helmet Ratings #12;Adult Football Helmet Detailed Ratings May 2012 Schutt ION 4D Sample 1 2 3

Lu, Chang

486

High performance distributed simulation for interactive simulated vascular reconstruction  

E-Print Network [OSTI]

performance. 1 Introduction Interactive simulation environments are dynamic systems that combine simula- tion.1 Performance of interactive simulation environments The most important factor in the performance of a dynamic dynamic simulation environment. 1 1 2 2 3 visualization rendering simulation time rendering delay

Amsterdam, Universiteit van

487

Particle simulation of auroral double layers. Doctoral thesis  

SciTech Connect (OSTI)

Externally driven magnetic reconnection has been proposed as a possible mechanism for production of auroral electrons during magnetic substorms. Fluid simulations of magnetic reconnection lead to strong plasma flows towards the increasing magnetic field of the earth. These plasma flows must generate large scale potential drops to preserve global charge neutrality. We have examined currentless injection of plasma along a dipole magnetic field into a bounded region using both analytic techniques and particle simulation.

Smith, B.L.

1992-06-01T23:59:59.000Z

488

Simulation of LMFBR  

SciTech Connect (OSTI)

The title of this session is taken to imply the system-wide thermohydraulic simulation of liquid metal fast breeder reactors (LMFBR). One is interested in predicting the temperatures, pressures, and the coolant flow rates throughout the entire plant including the reactor core, the primary and secondary sodium heat transport circuits, the steam generating system as well as other auxiliary circuits. Such a simulation is needed for (1) scoping studies (i.e., in the pre-design phase of a plant), (2) detailed design development, (3) the safety analysis (post-design development phase), and (4) the operator training and plant operation. This session emphasizes the simulation of LMFBRs for only two key categories of transients: operational disturbances or events and the post-shutdown heat removal.

Agrawal, A.K.

1982-01-01T23:59:59.000Z

489

Liquid filtration simulation  

SciTech Connect (OSTI)

We have a developed a computer code that simulates 3-D filtration of suspended particles in fluids in realistic filter structures. This code, being the most advanced filtration simulation package developed to date, provides LLNL and DOE with new capabilities to address problems in cleaning liquid wastes, medical fluid cleaning, and recycling liquids. The code is an integrated system of commercially available and LLNL-developed software; the most critical are the computational fluid dynamics (CFD) solver and the particle transport program. For the CFD solver, we used a commercial package based on Navier-Stokes equations and a LLNL-developed package based on Boltzman-lattice gas equations. For the particle transport program, we developed a cod based on the 3-D Langevin equation of motion and the DLVO theory of electrical interactions. A number of additional supporting packages were purchased or developed to integrate the simulation tasks and to provide visualization output.

Corey, I.; Bergman, W.

1996-06-01T23:59:59.000Z

490

Large mode-volume, large beta, photonic crystal laser resonator  

SciTech Connect (OSTI)

We propose an optical resonator formed from the coupling of 13, L2 defects in a triangular-lattice photonic crystal slab. Using a tight-binding formalism, we optimized the coupled-defect cavity design to obtain a resonator with predicted single-mode operation, a mode volume five times that of an L2-cavity mode and a beta factor of 0.39. The results are confirmed using finite-difference time domain simulations. This resonator is very promising for use as a single mode photonic crystal vertical-cavity surface-emitting laser with high saturation output power compared to a laser consisting of one of the single-defect cavities.

Dezfouli, Mohsen Kamandar; Dignam, Marc M. [Department of Physics, Engineering Physics and Astronomy, Queen’s University, Kingston, ON K7L 3N6 (Canada)

2014-12-15T23:59:59.000Z

491

Simulation of three-dimensional shear flow around a nozzle-afterbody at high speeds  

SciTech Connect (OSTI)

In this paper, turbulent shear flows at supersonic and hypersonic speeds around a nozzle-afterbody are simulated. The three-dimensional, Reynolds-averaged Navier-Stokes equations are solved by a finite-volume and implicit method. The convective and the pressure terms are differenced by an upwind-biased algorithm. The effect of turbulence is incorporated by a modified Baldwin-Lomax eddy viscosity model. The success of the standard Baldwin-Lomax model for this flow type is shown by comparing it to a laminar case. These modifications made to the model are also shown to improve flow prediction when compared to the standard Baldwin-Lomax model. These modifications to the model reflect the effects of high compressibility, multiple walls, vortices near walls, and turbulent memory effects in the shear layer. This numerically simulated complex flowfield includes a supersonic duct flow, a hypersonic flow over an external double corner, a flow through a non-axisymmetric, internal-external nozzle, and a three-dimensional shear layer. The specific application is for the flow around the nozzle-afterbody of a generic hypersonic vehicle powered by a scramjet engine. The computed pressure distributions compared favorably with the experimentally obtained surface and off-surface flow surveys.

Baysal, O.; Hoffman, W.B. (Mechanical Engineering and Mechanics Dept., Old Dominion Univ., Norfolk, VA (United States))

1992-06-01T23:59:59.000Z

492

Theoretical Tools for Large Scale Structure  

E-Print Network [OSTI]

We review the main theoretical aspects of the structure formation paradigm which impinge upon wide angle surveys: the early universe generation of gravitational metric fluctuations from quantum noise in scalar inflaton fields; the well understood and computed linear regime of CMB anisotropy and large scale structure (LSS) generation; the weakly nonlinear regime, where higher order perturbation theory works well, and where the cosmic web picture operates, describing an interconnected LSS of clusters bridged by filaments, with membranes as the intrafilament webbing. Current CMB+LSS data favour the simplest inflation-based $\\Lambda$CDM models, with a primordial spectral index within about 5% of scale invariant and $\\Omega_\\Lambda \\approx 2/3$, similar to that inferred from SNIa observations, and with open CDM models strongly disfavoured. The attack on the nonlinear regime with a variety of N-body and gas codes is described, as are the excursion set and peak-patch semianalytic approaches to object collapse. The ingredients are mixed together in an illustrative gasdynamical simulation of dense supercluster formation.

J. R. Bond; L. Kofman; D. Pogosyan; J. Wadsley

1998-10-06T23:59:59.000Z

493

Large Component Removal/Disposal  

SciTech Connect (OSTI)

This paper describes the removal and disposal of the large components from Maine Yankee Atomic Power Plant. The large components discussed include the three steam generators, pressurizer, and reactor pressure vessel. Two separate Exemption Requests, which included radiological characterizations, shielding evaluations, structural evaluations and transportation plans, were prepared and issued to the DOT for approval to ship these components; the first was for the three steam generators and one pressurizer, the second was for the reactor pressure vessel. Both Exemption Requests were submitted to the DOT in November 1999. The DOT approved the Exemption Requests in May and July of 2000, respectively. The steam generators and pressurizer have been removed from Maine Yankee and shipped to the processing facility. They were removed from Maine Yankee's Containment Building, loaded onto specially designed skid assemblies, transported onto two separate barges, tied down to the barges, th en shipped 2750 miles to Memphis, Tennessee for processing. The Reactor Pressure Vessel Removal Project is currently under way and scheduled to be completed by Fall of 2002. The planning, preparation and removal of these large components has required extensive efforts in planning and implementation on the part of all parties involved.

Wheeler, D. M.

2002-02-27T23:59:59.000Z

494

Adaptive optics simulation performance improvements using reconfigurable logic  

E-Print Network [OSTI]

A technique used to accelerate an adaptive optics simulation platform using reconfigurable logic is described. The performance of parts of this simulation have been improved by up to 600 times (reducing computation times by this factor) by implementing algorithms within hardware and enables adaptive optics simulations to be carried out in a reasonable timescale. This demonstrates that it is possible to use reconfigurable logic to accelerate computational codes by very large factors when compared with conventional software approaches, and this has relevance for many computationally intensive applications. The use of reconfigurable logic for high performance computing is currently in its infancy and has never before been applied to this field.

Alastair Basden

2006-11-09T23:59:59.000Z

495

Muon simulation codes MUSIC and MUSUN for underground physics  

E-Print Network [OSTI]

The paper describes two Monte Carlo codes dedicated to muon simulations: MUSIC (MUon SImulation Code) and MUSUN (MUon Simulations UNderground). MUSIC is a package for muon transport through matter. It is particularly useful for propagating muons through large thickness of rock or water, for instance from the surface down to underground/underwater laboratory. MUSUN is designed to use the results of muon transport through rock/water to generate muons in or around underground laboratory taking into account their energy spectrum and angular distribution.

V. A. Kudryavtsev

2008-10-25T23:59:59.000Z

496

Expert systems for design and simulation  

SciTech Connect (OSTI)

We discuss work in progress on two expert systems. We are developing systems that use artificial intelligence techniques to simplify the use of large simulation codes and to help design complicated physical devices. The simulation codes are used in analyzing and designing weapons, and the devices are themselves part of weapon systems. But we focus not only on the particular applications, but also on the broader issues common to design problems: large solution spaces and tentative reasoning. We also discuss some practical difficulties encountered during the project. One expert system provides an interface between users and several simulation codes. It checks input for errors, builds input files for the codes, and submits jobs to a central computing facility. The other expert system helps turn a description of a device into a particular design. Currently this expert system includes three major parts: a translator of descriptions into designs, a graphics interface that presents the design to the user and allows him to manipulate it, and a refiner of designs. The latter is the ''smartest'' part of the system, and the target of much of our present efforts.

Aldridge, J.; Cerutti, J.; Draisin, W.; Steuerwalt, M.

1985-01-01T23:59:59.000Z

497

Advanced simulation of intelligent transportation systems  

SciTech Connect (OSTI)

A large-scale, comprehensive, scaleable simulation of an Intelligent Transportation System (ITS) has been developed which is capable of running on parallel computers and distributed (networked) computer systems. The simulator currently models instrumented {open_quotes}smart{close_quotes} vehicles with in-vehicle navigation units capable of optimal route planning and Traffic Management Centers (TMC). The TMC has probe vehicle tracking capabilities (display position and attributes of instrumented vehicles), and can provide two-way interaction with traffic to provide advisories and link times. Both the in-vehicle navigation module and the TMC feature detailed graphical user interfaces to support human-factors studies. The prototype has been developed on a distributed system of networked UNIX computers but is designed to run on parallel computers, such as ANL`s IBM SP-2, for large-scale problems. A novel feature of this approach is that vehicles are represented by autonomous computer processes which exchange messages with other processes. The vehicles have a behavior model which governs route selection and driving behavior, and can react to external traffic events much like real vehicles. With this approach, the simulation is scaleable to take advantage of emerging massively parallel processor (MPP) systems.

Ewing, T.; Doss, E.; Hanebutte, U.; Tentner, A. [Argonne National Lab., IL (United States)

1996-11-01T23:59:59.000Z

498

Simulation of geothermal subsidence  

SciTech Connect (OSTI)

The results of an assessment of existing mathematical models for subsidence simulation and prediction are summarized. The following subjects are discussed: the prediction process, physical processes of geothermal subsidence, computational models for reservoir flow, computational models for deformation, proficiency assessment, and real and idealized case studies. (MHR)

Miller, I.; Dershowitz, W.; Jones, K.; Myer, L.; Roman, K.; Schauer, M.

1980-03-01T23:59:59.000Z

499

FASTBUS simulation tools  

SciTech Connect (OSTI)

A generalized model of a FASTBUS master is presented. The model is used with simulation tools to aid in the specification, design, and production of FASTBUS slave modules. The model provides a mechanism to interact with the electrical schematics and software models to predict performance. The model is written in the IEEE std 1076-1987 hardware description language VHDL. A model of the ATC logic is also presented. VHDL was chosen to provide portability to various platforms and simulation tools. The models, in conjunction with most commercially available simulators, will perform all of the transactions specified in IEEE std 960-1989. The models may be used to study the behavior of electrical schematics and other software models and detect violations of the FASTBUS protocol. For example, a hardware design of a slave module could be studied, protocol violations detected and corrected before committing money to prototype development. The master model accepts a stream of high level commands from an ASCII file to initiate FASTBUS transactions. The high level command language is based on the FASTBUS standard routines listed in IEEE std 1177-1989. Using this standard-based command language to direct the model of the master, hardware engineers can simulate FASTBUS transactions in the language used by physicists and programmers to operate FASTBUS systems. 15 refs., 6 figs.

Dean, T.D. (Stanford Linear Accelerator Center, Menlo Park, CA (United States)); Haney, M.J. (Illinois Univ., Urbana, IL (United States))

1991-10-01T23:59:59.000Z

500

Enabling immersive simulation.  

SciTech Connect (OSTI)

The object of the 'Enabling Immersive Simulation for Complex Systems Analysis and Training' LDRD has been to research, design, and engineer a capability to develop simulations which (1) provide a rich, immersive interface for participation by real humans (exploiting existing high-performance game-engine technology wherever possible), and (2) can leverage Sandia's substantial investment in high-fidelity physical and cognitive models implemented in the Umbra simulation framework. We report here on these efforts. First, we describe the integration of Sandia's Umbra modular simulation framework with the open-source Delta3D game engine. Next, we report on Umbra's integration with Sandia's Cognitive Foundry, specifically to provide for learning behaviors for 'virtual teammates' directly from observed human behavior. Finally, we describe the integration of Delta3D with the ABL behavior engine, and report on research into establishing the theoretical framework that will be required to make use of tools like ABL to scale up to increasingly rich and realistic virtual characters.

McCoy, Josh (University of California Santa Cruz, Santa Cruz, CA); Mateas, Michael (University of California Santa Cruz, Santa Cruz, CA); Hart, Derek H.; Whetzel, Jonathan; Basilico, Justin Derrick; Glickman, Matthew R.; Abbott, Robert G.

2009-02-01T23:59:59.000Z