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1

Applied large eddy simulation  

Science Journals Connector (OSTI)

...2971-2983. doi:10.1098/rsta.2008.0303 . Audio Supplement Audio Supplement Audio files from the Applied large eddy simulation...fidelity. | Whittle Laboratory, Department of Engineering, University of Cambridge, Cambridge CB2 1PZ...

2009-01-01T23:59:59.000Z

2

Implicit Large Eddy Simulation  

National Nuclear Security Administration (NNSA)

Implicit Implicit Large Eddy Simulation (ILES) for High Reynolds Number Flows Len Margolin Applied Physics Division Los Alamos National Laboratory Collaborators: 1. Bill Rider (LANL) 2. Piotr Smolarkiewicz (NCAR) 3. Andrzej Wysogrodski (NCAR) 4. Fernando Grinstein (NRL) len@lanl.gov 1 Implicit Large Eddy Simulation Outline: * What is ILES? * What are its advantages? * Historical perspective * Why does it work? * Some examples len@lanl.gov 2 What is ILES ILES is the direct application of a fluid solver to a high Reynolds number fluid flow with no explicit turbulence model. · The truncation terms of the algorithm serve as an effective model of the effects of the unresolved scales. · Fluid solvers based on Nonoscillatory Finite Volume (NFV) approximations work effectively for ILES. · Fluid solvers based on pseudospectral methods, leapfrog methods, advective form methods, etc. do not work

3

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

4

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

5

Large eddy simulation applications in gas turbines  

Science Journals Connector (OSTI)

...challenges. In SciDAC 2008 Conference, Seattle, USA. Jones, W.P. 2002Large eddy simulation of turbulent combustion processes. Comput. Phys. Commun. 147, 533-537. doi:10.1016/S0010-4655(02)00330-2 . Jones, W.P...

2009-01-01T23:59:59.000Z

6

Large Eddy Simulation of PBL Stratocumulus: Comparison of Multi...  

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

Large-Eddy Simulation of PBL Stratocumulus: Comparison of Multi-Dimensional and IPA Longwave Radiative Forcing D. B. Mechem and Y. L. Kogan Cooperative Institute for Mesoscale...

7

Large-Eddy Simulation for Green Energy and Propulsion Systems...  

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

Large-Eddy Simulation for Green Energy and Propulsion Systems PI Name: Umesh Paliath PI Email: paliath@ge.com Institution: General Electric Allocation Program: INCITE Allocation...

8

Large Eddy Simulation of Trade Wind Cumulus Clouds  

Science Journals Connector (OSTI)

A large eddy simulation (LES) model, used for studying the dry convective boundary layer, has been extended with an equation for the total water specific humidity and a condensation scheme to simulate the partly cloudy convective boundary layer. ...

J. W. M. Cuijpers; P. G. Duynkerke

1993-12-01T23:59:59.000Z

9

Large-Eddy Simulation of Swirling Pulverized-Coal Combustion  

Science Journals Connector (OSTI)

A Eulerian-Lagrangian large-eddy simulation (LES) with a Smagorinsky-Lilly sub-grid scale stress model, presumed-PDF fast chemistry and EBU gas combustion models, particle devolatilization and particle combustion

L. Y. Hu; L. X. Zhou; Y. H. Luo; C. S. Xu

2013-01-01T23:59:59.000Z

10

Using large eddy simulations to understand flow mixing | Argonne National  

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

large eddy simulations to understand flow mixing large eddy simulations to understand flow mixing March 4, 2013 Tweet EmailPrint In nuclear power plants, turbulent flow streams of different velocity and density mix rapidly at right angles in pipes. If those mixing flow streams are of different temperatures, thermal fluctuations result on the pipe wall. Such fluctuations can damage a pipe's structure and, ultimately, cause its failure. To better understand this phenomenon and to predict the effects, scientists have developed modeling methods known as large eddy simulations (LES). LES models only the energy-carrying large scales of motion, using a filtering mechanism to account for subgrid-scale motion. Thanks to recent advances in high-performance computing, the technique has become increasingly popular for simulating unsteady flows, allowing high fidelity

11

Applications of large eddy simulation methods to gyrokinetic turbulence  

SciTech Connect (OSTI)

The large eddy simulation (LES) approachsolving numerically the large scales of a turbulent system and accounting for the small-scale influence through a modelis 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.

Ban Navarro, A., E-mail: alejandro.banon.navarro@ipp.mpg.de; Happel, T. [Max-Planck-Institut fr Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)] [Max-Planck-Institut fr 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 fr Sonnensystemforschung, Max-Planck-Str. 2, D-37191 Katlenburg-Lindau (Germany); Max-Planck/Princeton Center for Plasma Physics (Germany); Jenko, F. [Max-Planck-Institut fr Plasmaphysik, EURATOM Association, D-85748 Garching (Germany) [Max-Planck-Institut fr 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

12

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:...

13

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

14

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.

15

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

16

Large Eddy Simulation of wind farm aerodynamics: A review  

Science Journals Connector (OSTI)

Abstract To study wind farm aerodynamics (WFA), the Wind Power industry currently relies on simple Engineering Models (EM) that simulate wind farms using basic principles of physics and empirically established approximations. \\{EMs\\} are fast and accurate for an overview of WFA and gauging mean power production, but cannot resolve phenomena like wake meandering, effect of atmospheric stratification on wake development, a turbine?s response to partial wake interaction and yawed inflows etc., and their relation with turbine loading, which require a first principle physics-based model, namely Computational Fluid Dynamics (CFD). Although advances in computer technology have promoted the application of CFD, the study of WFA is yet unworkable with Direct Numerical Simulation, which is the most comprehensive CFD technique. Thus, as a trade-off between cost and detail, researchers must resort to Large Eddy Simulation (LES) to garner thorough knowledge of WFA, which could in succession help the industry improve engineering models. This paper summarises the contributions of various LES investigations into WFA and how they have helped broaden our understanding of the subject. Additionally, the article touches upon the optimal use of LES and of the resultant data, and also the challenges faced by LES.

D. Mehta; A.H. van Zuijlen; B. Koren; J.G. Holierhoek; H. Bijl

2014-01-01T23:59:59.000Z

17

Large-eddy simulation of offshore wind farm  

Science Journals Connector (OSTI)

A hybrid numerical capability is developed for the simulation of offshore wind farms in which large-eddy simulation is performed for the wind turbulence and a potential flow based method is used for the simulation of the ocean wave field. The wind and wave simulations are dynamically coupled. The effect of wind turbines on the wind field is represented by an actuator disk model. This study focuses on the effect of wind-seas and the turbine motion is treated as negligibly small. A variety of fully-developed and fetch-limited wind-sea conditions and turbine spacings are considered in the study. Statistical analyses are performed for the simulation results with a focus on the mean wind profile kinetic energy budget in the wind field and the wind turbine power extraction rate. The results indicate that the waves have appreciable effect on the wind farm performance. The wind turbines obtain a higher wind power extraction rate under the fully developed wind-sea condition compared with that under the fetch-limited condition. This higher extraction rate is caused by the faster propagating waves and the lower sea-surface resistance on the wind when the wind-seas are fully developed. The wave-induced difference can be as high as 8% with the commonly used turbine spacing in commercial land-based wind farms s x = 7 (with s x being the ratio of streamwise turbine spacing to the turbine diameter). Such level of difference is noteworthy considering the previous understanding that direct wave-induced disturbance to the wind field decays exponentially away from wave surface.

2014-01-01T23:59:59.000Z

18

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

19

Linear eddy mixing based tabulation and artificial neural networks for large eddy simulations of turbulent flames  

SciTech Connect (OSTI)

A large eddy simulation (LES) sub-grid model is developed based on the artificial neural network (ANN) approach to calculate the species instantaneous reaction rates for multi-step, multi-species chemical kinetics mechanisms. The proposed methodology depends on training the ANNs off-line on a thermo-chemical database representative of the actual composition and turbulence (but not the actual geometrical problem) of interest, and later using them to replace the stiff ODE solver (direct integration (DI)) to calculate the reaction rates in the sub-grid. The thermo-chemical database is tabulated with respect to the thermodynamic state vector without any reduction in the number of state variables. The thermo-chemistry is evolved by stand-alone linear eddy mixing (LEM) model simulations under both premixed and non-premixed conditions, where the unsteady interaction of turbulence with chemical kinetics is included as a part of the training database. The proposed methodology is tested in LES and in stand-alone LEM studies of three distinct test cases with different reduced mechanisms and conditions. LES of premixed flame-turbulence-vortex interaction provides direct comparison of the proposed ANN method against DI and ANNs trained on thermo-chemical database created using another type of tabulation method. It is shown that the ANN trained on the LEM database can capture the correct flame physics with accuracy comparable to DI, which cannot be achieved by ANN trained on a laminar premix flame database. A priori evaluation of the ANN generality within and outside its training domain is carried out using stand-alone LEM simulations as well. Results in general are satisfactory, and it is shown that the ANN provides considerable amount of memory saving and speed-up with reasonable and reliable accuracy. The speed-up is strongly affected by the stiffness of the reduced mechanism used for the computations, whereas the memory saving is considerable regardless. (author)

Sen, Baris Ali; Menon, Suresh [School of Aerospace Engineering, Georgia Institute of Technology, 270 Ferst Drive, Atlanta, GA 30332-0150 (United States)

2010-01-15T23:59:59.000Z

20

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

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

Large Eddy Simulation of the Wind Field and Pollution Dispersion in Building Array  

Science Journals Connector (OSTI)

The air quality is one of the significant issues in sustainable development of modern city. In the paperthe Large Eddy Simulation (LES) is used to predict the wind field and pollution dispersion in residence dist...

R. F. Shi; G. X. Cui; C. X. Xu; Z. S. Zhang

2009-01-01T23:59:59.000Z

22

Large Eddy Simulation of Wind Turbulence forAppropriate Urban Environment  

Science Journals Connector (OSTI)

This study shows the numerical model which has the actual shape of the urban surface in order to analyze the wind turbulence in a city by large eddy simulation (LES) technique. Predictive accuracy of LES ... haza...

Tetsuro Tamura

2010-01-01T23:59:59.000Z

23

Using Large Eddy Simulations to Understand Combustion Instabilities in Gas Turbines  

Science Journals Connector (OSTI)

This paper presents a study of the stability of a swirled premixed combustion chamber both with and without reaction using Large Eddy Simulation and a numerical solver able to handle complex geometries. It is ...

Thierry Poinsot; Jrg Schlter

2002-01-01T23:59:59.000Z

24

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

25

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

26

Large-Eddy Simulation of Marine Atmospheric Boundary Layers above a Spectrum of Moving Waves  

Science Journals Connector (OSTI)

Momentum and scalar transport in the marine atmospheric boundary layer (MABL) is driven by a turbulent mix of winds, buoyancy, and surface gravity waves. To investigate the interaction between these processes, a large-eddy simulation (LES) model ...

Peter P. Sullivan; James C. McWilliams; Edward G. Patton

2014-11-01T23:59:59.000Z

27

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

28

Nesting large-eddy simulations within mesoscale simulations for wind energy applications  

SciTech Connect (OSTI)

With increasing demand for more accurate atmospheric simulations for wind turbine micrositing, for operational wind power forecasting, and for more reliable turbine design, simulations of atmospheric flow with resolution of tens of meters or higher are required. These time-dependent large-eddy simulations (LES), which resolve individual atmospheric eddies on length scales smaller than turbine blades and account for complex terrain, are possible with a range of commercial and open-source software, including the Weather Research and Forecasting (WRF) model. In addition to 'local' sources of turbulence within an LES domain, changing weather conditions outside the domain can also affect flow, suggesting that a mesoscale model provide boundary conditions to the large-eddy simulations. Nesting a large-eddy simulation within a mesoscale model requires nuanced representations of turbulence. Our group has improved the Weather and Research Forecasting model's (WRF) LES capability by implementing the Nonlinear Backscatter and Anisotropy (NBA) subfilter stress model following Kosovic (1997) and an explicit filtering and reconstruction technique to compute the Resolvable Subfilter-Scale (RSFS) stresses (following Chow et al, 2005). We have also implemented an immersed boundary method (IBM) in WRF to accommodate complex terrain. These new models improve WRF's LES capabilities over complex terrain and in stable atmospheric conditions. We demonstrate approaches to nesting LES within a mesoscale simulation for farms of wind turbines in hilly regions. Results are sensitive to the nesting method, indicating that care must be taken to provide appropriate boundary conditions, and to allow adequate spin-up of turbulence in the LES domain.

Lundquist, J K; Mirocha, J D; Chow, F K; Kosovic, B; Lundquist, K A

2008-09-08T23:59:59.000Z

29

Resolved Turbulence Characteristics in Large-Eddy Simulations Nested within Mesoscale Simulations Using the Weather Research and Forecasting Model  

Science Journals Connector (OSTI)

One-way concurrent nesting within the Weather Research and Forecasting Model (WRF) is examined for conducting large-eddy simulations (LES) nested within mesoscale simulations. Wind speed, spectra, and resolved turbulent stresses and turbulence ...

Jeff Mirocha; Branko Kosovi?; Gokhan Kirkil

2014-02-01T23:59:59.000Z

30

Effect of fluctuating wind direction on cross natural ventilation in buildings from large eddy simulation  

E-Print Network [OSTI]

wind direction, and the simulated results agree reasonably with the corresponding experimental data is the use of small-scale models in a wind tunnel to simulate natural ventilation. In general, the mean flow1 Effect of fluctuating wind direction on cross natural ventilation in buildings from large eddy

Chen, Qingyan "Yan"

31

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

32

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

33

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 and coupled with the LES solver of the gas phase. The equations used for each phase and the coupling terms

34

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

35

Large Eddy Simulation of spark ignition in a turbulent methane jet  

E-Print Network [OSTI]

and propagation and (4) stabilization. In the context of laser and electrical spark ignition (which is the scope applications of laser ignition and comparison with standard spark plug devices. Phuoc et al. [5] presentLarge Eddy Simulation of spark ignition in a turbulent methane jet G. Lacaze a , E. Richardson b

Paris-Sud XI, Université de

36

Persistent Contrails and Contrail Cirrus. Part I: Large-Eddy Simulations from Inception to Demise  

Science Journals Connector (OSTI)

Large-eddy simulations with size-resolved microphysics are used to model persistent aircraft contrails and contrail-induced cirrus from a few wing spans behind the aircraft until their demise after many hours. Schemes for dynamic local ice binning ...

D. C. Lewellen; O. Meza; W. W. Huebsch

2014-12-01T23:59:59.000Z

37

Large eddy simulation of flows in industrial compressors: a path from 2015 to 2035  

Science Journals Connector (OSTI)

...using two different turbine designs. J. Turbomach...eddy simulation for turbines: methodologies...eddy simulation of gas turbine compressors. Progr...T Poinsot. 2009 Development and assessment of a coupled strategy for conjugate heat...

2014-01-01T23:59:59.000Z

38

On integrating large eddy simulation and laboratory turbulent flow experiments  

Science Journals Connector (OSTI)

...effective simulation strategy mostly by necessity...its analysis and development, further understanding...directed research and development program at Los...multi-swirl gas turbine combustor. Proc...simulation of a gas turbine combustor flow...

2009-01-01T23:59:59.000Z

39

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

E-Print Network [OSTI]

the strength and ability to push forward and succeed. I owe you guys everything and nobody could ask for a better family. I love you all. iv NOMENCLATURE CFD Computational Fluid Dynamics DNS Direct Numerical Simulation RANS Reynolds Averaged Navier...-Stokes LES Large Eddy Simulation FEM Finite Element Method SEM Spectral Element Method SGS Sub-Grid Scale TLM Two Layer Method Re Reynolds Number Re Friction Reynolds Number U1 Characteristic Velocity GLL Gauss-Lobatto-Legendre Cs Smagorinski Coe...

Rabau, Joshua I

2013-05-01T23:59:59.000Z

40

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

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

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...

42

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

43

Computational modelling of transport phenomena in high energy materials processing application: large eddy simulation and parallelisation  

Science Journals Connector (OSTI)

A comprehensive three-dimensional numerical model is presented in order to address the coupled turbulent momentum, heat and species transport during molten metal-pool convection in association with continuous evolution of solid-liquid interface typically encountered in high energy materials processing applications. The turbulent aspect is handled by a large eddy simulation (LES) model and the phase changing phenomena is taken care of by a modified enthalpy-porosity technique. The proposed finite volume based LES model is subsequently parallelised for effective computational economy. To demonstrate the effectiveness of the present model, a systematic analysis is subsequently carried out to simulate a typical high power laser surface alloying process, where the effects of turbulent transport can actually be realised.

Dipankar Chatterjee

2011-01-01T23:59:59.000Z

44

Large-Eddy Simulation of Langmuir Turbulence in Pure Wind Seas  

Science Journals Connector (OSTI)

The scaling of turbulent kinetic energy (TKE) and its vertical component (VKE) in the upper ocean boundary layer, forced by realistic wind stress and surface waves including the effects of Langmuir circulations, is investigated using large-eddy ...

Ramsey R. Harcourt; Eric A. DAsaro

2008-07-01T23:59:59.000Z

45

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

46

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

47

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 than current models. As the market for wind energy grows, wind turbines and wind plants are becoming

48

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

49

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

50

LARGE EDDY SIMULATION AND REYNOLDS-AVERAGED NAVIER-STOKES APPROACHES OF RIB ROUGHENED CHANNEL  

E-Print Network [OSTI]

In this paper, rib roughened channel are investigated numerically by large eddy simulation (LES) and Reynolds-averaged Navier-Stokes (RANS) approaches. Results are compared with each other in streamlines and velocity components. During the present analysis, working domain is considered as three-dimensional (3-D) and the flow is assumed fully turbulent. Domain geometry and grids are generated by using a pre-processor of GAMBIT and then solved iteratively by a commercially available CFD code of FLUENT 6.2.16. Main purpose of this study is to show the capability of the CFD solver and the effect of the rib on the flow by comparing two different solution techniques.

unknown authors

51

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

52

Large-eddy simulation of flows over two-dimensional idealised street canyons with height variation  

Science Journals Connector (OSTI)

A series of large-eddy simulation (LES) models consisting of two-dimensional (2D) idealised street canyons with building height variability (BHV) are examined. Building blocks with two different heights are placed alternately in the computational domains, constructing repeated street canyons of building-height-to-street-width (aspect) ratio (AR) = 1, 0.5, 0.25 and 0.125 together with BHV = 0.2, 0.4 and 0.6. LES results show that the air exchange rate (ACH) increases with increasing aerodynamic resistance. Apart from AR, BHV is another factor affecting the aerodynamic resistance and thus the ACH. The (vertical) dispersion coefficient ?z of plume transport is also closely related to the aerodynamic resistance, suggesting that introducing BHV in urban areas could help improve the air quality.

Colman C.C. Wong; Chun-Ho Liu

2014-01-01T23:59:59.000Z

53

A large-eddy simulation study of wake propagation and power production in an array of tidal-current turbines  

Science Journals Connector (OSTI)

...production in an array of tidal-current turbines Matthew J. Churchfield Ye Li Patrick...performing large-eddy simulations of tidal turbine array flows. First, a horizontally periodic...those data are used as inflow into a tidal turbine array two rows deep and infinitely wide...

2013-01-01T23:59:59.000Z

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 LES September 2012 Abstract We report a large-eddy simulation (LES)/probability density function (PDF) study/PDF modeling approach, recent progress of LES of tur- bulent combustion is reviewed in [10]. In the modeling

55

Large-Eddy Simulation of a Residual Layer: Low-Level Jet, Convective Rolls, and KelvinHelmholtz Instability  

Science Journals Connector (OSTI)

Diurnal variations of an atmospheric boundary layer from 0900 LST on day 33 to 0600 LST on day 34 of the Wangara experiment are studied using a large-eddy simulation (LES) model that includes longwave radiation and baroclinicity. The present study ...

Mikio Nakanishi; Ryosuke Shibuya; Junshi Ito; Hiroshi Niino

2014-12-01T23:59:59.000Z

56

Large eddy simulation of flows in industrial compressors: a path from 2015 to 2035  

Science Journals Connector (OSTI)

...eddy simulation of flows in industrial compressors: a path from...flow that develops in such industrial machines is extremely hard...TM-2009-215627, NASA Glenn Research Center. 6 McMullan, WA , and GJ...Poinsot. 2009 Development and assessment of a coupled strategy for...

2014-01-01T23:59:59.000Z

57

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

58

Development and assessment of a coupled strategy for conjugate heat transfer with Large Eddy Simulation.  

E-Print Network [OSTI]

Development and assessment of a coupled strategy for conjugate heat transfer with Large Eddy is an important phenomenon in combustion chambers and a main design constraint in gas turbines. After combustion is to develop 3 hal-00803384,version1-22Mar2013 #12;and assess a suitable strategy based on LES to efficiently

Paris-Sud XI, Université de

59

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

60

Large-Eddy Simulation of Stratified Turbulence. Part II: Application of the Stretched-Vortex Model to the Atmospheric Boundary Layer  

Science Journals Connector (OSTI)

The buoyancy-adjusted stretched-vortex subgrid-scale (SGS) model is assessed for a number of large-eddy simulations (LESs) corresponding to diverse atmospheric boundary layer conditions. The cases considered are free convection, a moderately ...

Georgios Matheou; Daniel Chung

2014-12-01T23:59:59.000Z

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.


61

Coupled fluid-structure interaction simulation of floating offshore wind turbines and waves: a large eddy simulation approach  

Science Journals Connector (OSTI)

We develop a computational framework for simulating the coupled interaction of complex floating structures with large-scale ocean waves and atmospheric turbulent winds. The near-field approach features a partitioned fluid-structure interaction model (FSI) combining the curvilinear immersed boundary (CURVIB) method of Borazjani and Sotiropoulos (J. Comput. Phys. 2008) and the two-phase flow level set formulation of Kang and Sotiropoulos (Adv. in Water Res. 2012) and is capable of solving complex free-surface flows interacting non-linearly with complex real life floating structures. The near-field solver is coupled with a large-scale wave and wind model based on the two-fluid approach of Yang and Shen (J. Comput. Phys. 2011) which integrates a viscous Navier-Stokes solver with undulatory boundaries for the motion of the air and an efficient potential-flow based wave solver. The large-scale turbulent wind is incorporated from the far-field solver to the near-field solver by feeding into the latter inlet boundary conditions. The wave field is incorporated to the near-field solver by using the pressure-forcing method of Guo and Shen (J. Comput. Phys. 2009) which has been appropriately adapted to the level set method. The algorithm for coupling the two codes has been validated for a variety of wave cases including a broadband spectrum showing excellent agreement when compared to theoretical results. Finally, the capabilities of the numerical framework are demonstrated by carrying out large eddy simulation (LES) of a floating wind turbine interacting with realistic ocean wind and wave conditions.

Antoni Calderer; Xin Guo; Lian Shen; Fotis Sotiropoulos

2014-01-01T23:59:59.000Z

62

The prospect of using large eddy and detached eddy simulations in engineering design, and the research required to get there  

Science Journals Connector (OSTI)

...causality-breaking simulation allows for...governing equations are satisfied...equation. The process is illustrated...impact of Matlab, which democratized matrix manipulations...the design process? This is...causality-breaking simulation only need...TR-2008-13.pdf . 2 Amarasinghe...Navier-Stokes equations on up to...

2014-01-01T23:59:59.000Z

63

Large-Eddy Simulation Study of Wake Propagation and Power Production in an Array of Tidal-Current Turbines: Preprint  

SciTech Connect (OSTI)

This paper presents our initial work in performing large-eddy simulations of tidal turbine array flows. First, a horizontally-periodic precursor simulation is performed to create turbulent flow data. Then that data is used to determine the inflow into a tidal turbine array two rows deep and infinitely wide. The turbines are modeled using rotating actuator lines, and the finite-volume method is used to solve the governing equations. In studying the wakes created by the turbines, we observed that the vertical shear of the inflow combined with wake rotation causes lateral wake asymmetry. Also, various turbine configurations are simulated, and the total power production relative to isolated turbines is examined. Staggering consecutive rows of turbines in the simulated configurations allows the greatest efficiency using the least downstream row spacing. Counter-rotating consecutive downstream turbines in a non-staggered array shows a small benefit. This work has identified areas for improvement, such as the use of a larger precursor domain to better capture elongated turbulent structures, the inclusion of salinity and temperature equations to account for density stratification and its effect on turbulence, improved wall shear stress modeling, and the examination of more array configurations.

Churchfield, M. J.; Li, Y.; Moriarty, P. J.

2011-07-01T23:59:59.000Z

64

Large-Eddy Simulation Study of Wake Propagation and Power Production in an Array of Tidal-Current Turbines: Preprint  

SciTech Connect (OSTI)

This paper presents our initial work in performing large-eddy simulations of tidal turbine array flows. First, a horizontally-periodic precursor simulation is performed to create turbulent flow data. Then that data is used as inflow into a tidal turbine array two rows deep and infinitely wide. The turbines are modeled using rotating actuator lines, and the finite-volume method is used to solve the governing equations. In studying the wakes created by the turbines, we observed that the vertical shear of the inflow combined with wake rotation causes lateral wake asymmetry. Also, various turbine configurations are simulated, and the total power production relative to isolated turbines is examined. Staggering consecutive rows of turbines in the simulated configurations allows the greatest efficiency using the least downstream row spacing. Counter-rotating consecutive downstream turbines in a non-staggered array shows a small benefit. This work has identified areas for improvement, such as the use of a larger precursor domain to better capture elongated turbulent structures, the inclusion of salinity and temperature equations to account for density stratification and its effect on turbulence, improved wall shear stress modelling, and the examination of more array configurations.

Churchfield, M. J.; Li, Y.; Moriarty, P. J.

2012-07-01T23:59:59.000Z

65

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

66

The Dispersion of Silver Iodide Particles from Ground-Based Generators over Complex Terrain. Part II: WRF Large-Eddy Simulations versus Observations  

Science Journals Connector (OSTI)

A numerical modeling study has been conducted to explore the ability of the Weather Research and Forecasting (WRF) model-based large-eddy simulation (LES) with 100-m grid spacing to reproduce silver iodide (AgI) particle dispersion by comparing ...

Lulin Xue; Xia Chu; Roy Rasmussen; Daniel Breed; Bruce Boe; Bart Geerts

2014-06-01T23:59:59.000Z

67

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

68

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

69

Large eddy simulation of wind turbine wake dynamics in the stable boundary layer using the Weather Research and Forecasting Model  

Science Journals Connector (OSTI)

Recently an actuator disk parameterization was implemented in the Weather Research and Forecasting (WRF) Model for large eddy simulation (LES) of wind turbine wakes. To thoroughly verify this model simulations of various types of turbines and atmospheric conditions must be evaluated against corresponding experimental data. In this work numerical simulations are compared to nacelle-based scanning lidar measurements taken in stable atmospheric conditions during a field campaign conducted at a wind farm in the western United States. Using several wake characteristicssuch as the velocity deficit centerline location and wake widthas metrics for model verification the simulations show good agreement with the observations. Notable results include a high average velocity deficit decreasing from 73% at a downwind distance x of 1.2 rotor diameters (D) to 25% at x?=?6.6D resulting from a low average wind speed and therefore high average turbine thrust coefficient. Moreover the wake width expands from 1.4D at x?=?1.2D to 2.3D at x?=?6.6D. Finally new featuresnamely rotor tilt and drag from the nacelle and towerare added to the existing actuator disk model in WRF-LES. Compared to the rotor the effect of the tower and nacelle on the flow is relatively small but nevertheless important for an accurate representation of the entire turbine. Adding rotor tilt to the model causes the vertical location of the wake center to shift upward. Continued advancement of the actuator disk model in WRF-LES will help lead to optimized turbine siting and controls at wind farms.

Matthew L. Aitken; Branko Kosovi?; Jeffrey D. Mirocha; Julie K. Lundquist

2014-01-01T23:59:59.000Z

70

Experimental study of an active grid-generated shearless mixing layer and comparisons with large-eddy simulation  

Science Journals Connector (OSTI)

A shearless mixing layer characterized by interactions between two regions with different turbulence intensities but without mean shear is investigated experimentally in a wind tunnel. Reynolds numbers higher than those of prior studies [B. Gilbert Diffusion mixing in grid turbulence without mean shear J. Fluid Mech.100 349 (1980); S. Veeravalli and Z. Warhaft The shearless turbulent mixing layer J. Fluid Mech.207 191 (1989); B. Knaepen O. Debliquy and D. Carati Direct numerical simulation and large-eddy simulation of a shear-free mixing layer J. Fluid Mech.514 153 (2004); D. Tordella and M. Iovieno Numerical experiments on the intermediate asymptotics of shear-free turbulent transport and diffusion J. Fluid Mech.549 429 (2006); D. A. Briggs J. H. Ferziger J. R. Koseff and S. G. Monismith Entrainment in a shear-free turbulent mixing layer J. Fluid Mech.310 215 (1996)] are achieved by using an active grid with rotating winglets on one-half of its cross section. Stationary flow-conditioning fine meshes are used to avoid mean velocity gradients. Measurements are performed at five different downstream wind-tunnel locations using an X-type hot-wire probe and a stereoscopic particle image velocimetry system. The Reynolds numbers based on the Taylor microscale in the high- and low-kinetic energy regions are 170 and 88 respectively. The energy and integral length-scale ratios between the two regions are 4.27 and 1.73 respectively. The inlet turbulence in the upper and lower portions of the shearless mixing layer is not fully isotropic with the streamwise velocityfluctuations being between 6% and 13% higher than the cross-stream ones. Fundamental statistical properties of the flow are documented and analyzed at various scales using band-pass box-filtered velocities. Downstream evolution of variance and half-width of the mixing layer skewness and flatness factors as well as the statistics of two-point velocity increments at various displacements are presented. It is found that much of the deviations from Gaussian statistics originate from large-scale motions. The data are well suited to be used as initial condition for simulations and as test for large-eddy simulation(LES)models and codes. Comparison studies for three LESmodels including Smagorinsky dynamic Smagorinsky and dynamic mixed nonlinear models are implemented in simulations of temporally decaying shearless mixing layer using a pseudospectral code. Initial conditions are prescribed by matching the longitudinal energy spectra at all heights across the layer for both streamwise and cross-stream velocity components. LES with all three subgrid scale models tested underpredicts the kinetic energy and exhibits deviations from the measured non-Gaussian behaviors. Overall the dynamic Smagorinsky model predicts statistics slightly better than the other two models.

Hyung Suk Kang

2008-01-01T23:59:59.000Z

71

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

72

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

73

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

E-Print Network [OSTI]

the effects of array layout on the performance of offshore wind farms. Array layout is characterized by the spacing between wind turbines (along and across the prevailing wind direction) and by their alignment and is coupled with an actuator line model to simulate the effects of the rotating wind turbine blades. A control

74

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

75

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

76

A Large-Eddy Simulation Study of Wake Propagation and Power Production in an Array of Tidal-Current Turbines: Preprint  

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

Large-Eddy Simulation Study Large-Eddy Simulation Study of Wake Propagation and Power Production in an Array of Tidal- Current Turbines Preprint M.J. Churchfield, Y. Li, and P.J. Moriarty To be presented at the 9 th European Wave and Tidal Energy Conference 2011 Southhampton, England September 4 - 9, 2011 Conference Paper NREL/CP-5000-51765 July 2011 NOTICE The submitted manuscript has been offered by an employee of the Alliance for Sustainable Energy, LLC (Alliance), a contractor of the US Government under Contract No. DE-AC36-08GO28308. Accordingly, the US Government and Alliance retain a nonexclusive royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for US Government purposes. This report was prepared as an account of work sponsored by an agency of the United States government.

77

Large-eddy simulations of impinging over-expanded supersonic jet noise for launcher applications  

Science Journals Connector (OSTI)

During the lift-off phase of a space launcher powerful rocket motors generate harsh acoustic environment on the launch pad. Following the blast waves created at ignition jet noise is a major contributor to the acoustic loads received by the launcher and its payload. Recent simulations performed at ONERA to compute the noise emitted by solid rocket motors at lift-off conditions are described. Far-field noise prediction is achieved by associating a LES solution of the jet flow with an acoustics surface integral method. The computations are carried out with in-house codes CEDRE for the LES solution and KIM for Ffowcs Williams & Hawkings porous surface integration method. The test case is that of a gas generator fired vertically onto a 45 degrees inclined flat plate which impingement point is located 10 diameters from nozzle exit. Computations are run for varied numerical conditions such as turbulence modeling along the plate and different porous surfaces location and type. Results are discussed and compared with experimental acoustic measurements obtained by CNES at MARTEL facility.

2014-01-01T23:59:59.000Z

78

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 Alstoms 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 Alstoms 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 Utahs 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 Utahs 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

79

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

80

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]

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 an existing wind plant, augmenting previous studies of wind plant subsets. Wind turbines extract energy from

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

Implementation of a generalized actuator disk wind turbine model into the weather research and forecasting model for large-eddy simulation applications  

Science Journals Connector (OSTI)

A generalized actuator disk (GAD) wind turbine parameterization designed for large-eddy simulation (LES) applications was implemented into the Weather Research and Forecasting (WRF) model. WRF-LES with the GAD model enables numerical investigation of the effects of an operating wind turbine on and interactions with a broad range of atmospheric boundary layer phenomena. Numerical simulations using WRF-LES with the GAD model were compared with measurements obtained from the Turbine Wake and Inflow Characterization Study (TWICS-2011) the goal of which was to measure both the inflow to and wake from a 2.3-MW wind turbine. Data from a meteorological tower and two light-detection and ranging (lidar) systems one vertically profiling and another operated over a variety of scanning modes were utilized to obtain forcing for the simulations and to evaluate characteristics of the simulated wakes. Simulations produced wakes with physically consistent rotation and velocity deficits. Two surface heat flux values of 20?W m?2 and 100?W m?2 were used to examine the sensitivity of the simulated wakes to convective instability. Simulations using the smaller heat flux values showed good agreement with wake deficits observed during TWICS-2011 whereas those using the larger value showed enhanced spreading and more-rapid attenuation. This study demonstrates the utility of actuator models implemented within atmospheric LES to address a range of atmospheric science and engineering applications. Validated implementation of the GAD in a numerical weather prediction code such as WRF will enable a wide range of studies related to the interaction of wind turbines with the atmosphere and surface.

J. D. Mirocha; B. Kosovic; M. L. Aitken; J. K. Lundquist

2014-01-01T23:59:59.000Z

82

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]

Development and assessment of a coupled strategy for conjugate heat transfer with Large Eddy walls is an important phenomenon in combustion chambers and a main design constraint in gas turbines- tionally expensive method, the aim of this paper is to develop and assess a suitable strategy based on LES

Nicoud, Franck

83

A large-eddy simulation study of wake propagation and power production in an array of tidal-current turbines  

Science Journals Connector (OSTI)

...consecutive rows of turbines in the simulated...allows the greatest efficiency using the least...the next upstream turbines, an efficiency increase of about...performance and efficiency of a tidal turbine array. Table 1...

2013-01-01T23:59:59.000Z

84

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

85

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...

86

The Local Structure of Atmospheric Turbulence and Its Effect on the Smagorinsky Model for Large Eddy Simulation  

Science Journals Connector (OSTI)

Phenomena such as large-scale shear, buoyancy, and the proximity to the ground surface significantly affect interactions among scales in atmospheric boundary layer turbulent flows. Hence, these phenomena impact parameters that enter subgrid-scale ...

Marcelo Chamecki; Charles Meneveau; Marc B. Parlange

2007-06-01T23:59:59.000Z

87

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

88

Large eddy simulation applications in gas turbines  

Science Journals Connector (OSTI)

...exhaust plume development. The application...modelling in the gas turbine combustor...modelling strategies for the complex...flows in the gas turbine, as surveyed...of typical gas turbine parts necessitates...made in the development and application...

2009-01-01T23:59:59.000Z

89

Developing large eddy simulation for turbomachinery applications  

Science Journals Connector (OSTI)

...development. In Int. Conf. on Scientific and Engineering Computation, Singapore, July 2004...PhD thesis, Department of Mechanical Engineering, University of Sheffield, UK. Audio Supplement Audio Supplement Audio files from the Applied...

2009-01-01T23:59:59.000Z

90

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

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

Detached Eddy Simulation of a High-Lift Wing with Active Flow Control PI Name: Kenneth Jansen PI Email: jansenke@colorado.edu Institution: University of Colorado Allocation...

91

Lagrangian analysis of the vertical structure of eddies simulated in the Japan Basin of the Japan/East Sea  

E-Print Network [OSTI]

The output from an eddy-resolved multi-layered circulation model is used to analyze the vertical structure of simulated deep-sea eddies in the Japan Basin of the Japan/East Sea constrained by bottom topography. We focus on Lagrangian analysis of anticyclonic eddies, generated in the model in a typical year approximately at the place of the mooring and the hydrographic sections, where such eddies have been regularly observed in different years (1993--1997, 1999--2001). Using a quasi-3D computation of the finite-time Lyapunov exponents and displacements for a large number of synthetic tracers in each depth layer, we demonstrate how the simulated feature evolves of the eddy, that does not reach the surface in summer, into a one reaching the surface in fall. This finding is confirmed by computing deformation of the model layers across the simulated eddy in zonal and meridional directions and in the corresponding temperature cross sections. Computed Lagrangian tracking maps allow to trace the origin and fate of wa...

Prants, S V; Budyansky, M V; Uleysky, M Yu; Fyman, P A

2014-01-01T23:59:59.000Z

92

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

93

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

94

Adaptive Detached Eddy Simulation of a Vertical Tail with Active Flow  

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

Adaptive Detached Eddy Simulation of a Vertical Tail with Active Flow Control Adaptive Detached Eddy Simulation of a Vertical Tail with Active Flow Control Adaptive Detached Eddy Simulation of a Vertical Tail with Active Flow Control PI Name: Kenneth Jansen PI Email: jansenke@colorado.edu Institution: University of Colorado Allocation Program: INCITE Allocation Hours at ALCF: 40 Million Year: 2012 Research Domain: Engineering The use of fuel-and its accompanying costs-has become an increasing concern in many industries. Researchers are examining the issue of fuel reduction in commercial jet aircraft from the perspective of redesign. By redesigning the vertical tail of a commercial jet, they hope to reduce jet fuel use by 0.5%, resulting in annual savings of $300 million. Using -synthetic commercial jet aircraft, the team will perform a series

95

Mapping B1-induced eddy current effects near metallic structures in MR images: A comparison of simulation and experiment  

Science Journals Connector (OSTI)

Abstract Magnetic resonance imaging (MRI) in the presence of metallic structures is very common in medical and non-medical fields. Metallic structures cause MRI image distortions by three mechanisms: (1) static field distortion through magnetic susceptibility mismatch, (2) eddy currents induced by switched magnetic field gradients and (3) radio frequency (RF) induced eddy currents. Single point ramped imaging with T1 enhancement (SPRITE) MRI measurements are largely immune to susceptibility and gradient induced eddy current artifacts. As a result, one can isolate the effects of metal objects on the RF field. The RF field affects both the excitation and detection of the magnetic resonance (MR) signal. This is challenging with conventional MRI methods, which cannot readily separate the three effects. RF induced MRI artifacts were investigated experimentally at 2.4T by analyzing image distortions surrounding two geometrically identical metallic strips of aluminum and lead. The strips were immersed in agar gel doped with contrast agent and imaged employing the conical SPRITE sequence. B1 mapping with pure phase encode SPRITE was employed to measure the B1 field around the strips of metal. The strip geometry was chosen to mimic metal electrodes employed in electrochemistry studies. Simulations are employed to investigate the RF field induced eddy currents in the two metallic strips. The RF simulation results are in good agreement with experimental results. Experimental and simulation results show that the metal has a pronounced effect on the B1 distribution and B1 amplitude in the surrounding space. The electrical conductivity of the metal has a minimal effect.

S. Vashaee; F. Goora; M.M. Britton; B. Newling; B.J. Balcom

2015-01-01T23:59:59.000Z

96

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

97

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

98

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...

99

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...

100

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.


101

Large eddy simulation modelling of combustion for propulsion applications  

Science Journals Connector (OSTI)

...but also for power generation and for marine applications. The current trend is to...travel are the vehicle design and the propulsion system, and how to integrate them. Two types of propulsion systems, ramjets (Fry 2004) and scramjets...

2009-01-01T23:59:59.000Z

102

Large eddy simulation for aerodynamics: status and perspectives  

Science Journals Connector (OSTI)

...RANS-LES is the main strategy to drastically reduce...appear paradoxal since the development of advanced methods is...2.85 2.85-10 1 gas turbine Medic et al. (2008...computation of an entire gas turbine jet engine. In 45th...

2009-01-01T23:59:59.000Z

103

Examination of steam generator turbulence by large eddy simulation  

E-Print Network [OSTI]

coefficients were calculated and compared to experimental findings from Argonne National Laboratory. The calculation predicts several features that were exhibited in the experiment. The results, as compared to experiment, show that LES is capable...

Bagwell, Ted Glyn

2012-06-07T23:59:59.000Z

104

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

Broader source: Energy.gov [DOE]

2012 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting

105

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

106

Large-eddy simulation of multiphase flows in complex combustors  

E-Print Network [OSTI]

combustors and biomass gasifiers involv- ing swirling motions. The combustion chambers of propulsion systems of turbulent mixing and combustion dynamics. Our goal in the present work is to develop a computational tool combustion engines, liquid and solid propellant rocket motors, gas-turbine aircraft engines, cyclone

Mahesh, Krishnan

107

Weather Forecasting using GPU-based Large-Eddy Simulations  

Science Journals Connector (OSTI)

Since the advent of computers midway through the 20th century, computational resources have increased exponentially. It is likely they will continue to do so, especially when accounting for recent trends in multi-core processors. History has shown that ...

Jerme Schalkwijk; Harmen J.J. Jonker; A. Pier Siebesma; Erik van Meijgaard

108

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

109

Simulation of smoke plumes from large pool fires  

SciTech Connect (OSTI)

A large eddy simulation model of smoke plumes generated by large outdoor pool fires is presented. The plume is described in terms of steady-state convective transport by a uniform ambient wind of heated gases and particulate matter introduced into a stably stratified atmosphere by a continuously burning fire. The Navier-Stokes equations in the Boussinesq approximation are solved numerically with a constant eddy viscosity representing dissipation on length scales below the resolution limits of the calculation. The effective Reynolds number is high enough to permit direct simulation of the large scale mixing over two to three orders of magnitude in length scale. Particulate matter, or any nonreacting combustion product, is representing by Lagrangian particles that are advected by the fire-induced flow field. Background atmospheric motion is described in terms of the angular fluctuation of the prevailing wind and represented by random perturbations to the mean particle paths. Sample computations are presented and compared with plumes generated by large crude oil pool fires. Also presented is an assessment of the potential environmental hazard posed by burning marine oil spills.

Baum, H.R.; McGrattan, K.B.; Rehm, R.G. [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

1994-12-31T23:59:59.000Z

110

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)

Full span view of the flow past a vertical tail assembly of a commercial aircraft with active flow control at Re=360,000. Full span view of the flow past a vertical tail assembly of a commercial aircraft with active flow control at Re=360,000. Full span view of the flow past a vertical tail assembly of a commercial aircraft with active flow control at Re=360,000. This picture highlights the root and tip vortex along with the turbulent structures in the wake of a deflected rudder through isosurface of instantaneous Q criterion colored by speed on a locally adapted unstructured finite element mesh with 1.2 billion elements. Michel Rasquin, Argonne National Laboratory Adaptive Detached Eddy Simulation of a High-Lift Wing with Active Flow Control PI Name: Kenneth Jansen PI Email: jansenke@colorado.edu Institution: University of Colorado Allocation Program: INCITE Allocation Hours at ALCF:

111

Cyclonic eddies in the Gulf of Mexico: Observations by underwater gliders and simulations by numerical model  

Science Journals Connector (OSTI)

Circulation in the Gulf of Mexico (GoM) is dominated by the Loop Current (LC), and by Loop Current Eddies (LCEs) which form at irregular multi-month intervals by separation from the LC. Comparatively small cyclonic eddies (CEs) are thought to have ...

Daniel L. Rudnick; Ganesh Gopalakrishnan; Bruce D. Cornuelle

112

Sources of Eddy Energy Simulated by a Model of the Northeast Pacific Ocean  

Science Journals Connector (OSTI)

This paper examines the energy sources for eddy variability in the Gulf of Alaska using a numerical model and a novel form of data assimilation referred to as spectral nudging. Spectral nudging is distinguished from conventional nudging by its ...

Jennifer Shore; Michael W. Stacey; Daniel G. Wright

2008-10-01T23:59:59.000Z

113

Energy of Midlatitude Transient Eddies in Idealized Simulations of Changed Climates  

Science Journals Connector (OSTI)

As the climate changes, changes in static stability, meridional temperature gradients, and availability of moisture for latent heat release may exert competing effects on the energy of midlatitude transient eddies. This paper examines how the ...

Paul A. OGorman; Tapio Schneider

2008-11-01T23:59:59.000Z

114

An Energy-Constrained Parameterization of Eddy Buoyancy Flux  

Science Journals Connector (OSTI)

A parameterization for eddy buoyancy fluxes for use in coarse-grid models is developed and tested against eddy-resolving simulations. The development is based on the assumption that the eddies are adiabatic (except near the surface) and the ...

Paola Cessi

2008-08-01T23:59:59.000Z

115

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.

116

Energy spectra of quantum turbulence: Large-scale simulation and modeling  

Science Journals Connector (OSTI)

In a 20483 simulation of quantum turbulence within the Gross-Pitaevskii equation, it is demonstrated that the large-scale motions have a classical Kolmogorov-1941 energy spectrum E(k)?k?5/3, followed by an energy accumulation with E(k)? const at k about the reciprocal mean intervortex distance. This behavior was predicted by the L'vov-Nazarenko-Rudenko bottleneck model of gradual eddy-wave crossover [Lvov, Nazarenko, and Rudenko, J. Low Temp. Phys. 153, 140 (2008)], further developed in the paper.

Narimasa Sasa; Takuma Kano; Masahiko Machida; Victor S. Lvov; Oleksii Rudenko; Makoto Tsubota

2011-08-11T23:59:59.000Z

117

The prospect of using large eddy and detached eddy simulations in engineering design, and the research required to get there  

Science Journals Connector (OSTI)

...computer science in future...Research that advances our LES technology...flows, and recent research...realistic aerospace problems...approach. In Advances in DNS...52nd AIAA Aerospace Sciences Meeting...50th AIAA Aerospace Sciences Meeting...

2014-01-01T23:59:59.000Z

118

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

Science Journals Connector (OSTI)

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

Li Rongfeng; Zeng Qingcun; Ji Zhongzhen

1992-09-01T23:59:59.000Z

119

Simulation of large acceptance LINAC for muons  

SciTech Connect (OSTI)

There has been a recent need for muon accelerators not only for future Neutrino Factories and Muon Colliders but also for other applications in industry and medical use. We carried out simulations on a large-acceptance muon linac with a new concept 'mixed buncher/acceleration'. The linac can accept pions/muons from a production target with large acceptance and accelerate muon without any beam cooling which makes the initial section of muon-linac system very compact. The linac has a high impact on Neutrino Factory and Muon Collider (NF/MC) scenario since the 300-m injector section can be replaced by the muon linac of only 10-m length. The current design of the linac consists of the following components: independent 805-MHz cavity structure with 6- or 8-cm-radius aperture window; injection of a broad range of pion/muon energies, 10-100 MeV, and acceleration to 150 - 200 MeV. Further acceleration of the muon beam are relatively easy since the beam is already bunched.

Miyadera, H [Los Alamos National Laboratory; Kurennoy, S [Los Alamos National Laboratory; Jason, A J [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

120

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

Broader source: Energy.gov [DOE]

2011 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer Evaluation

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 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

122

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

E-Print Network [OSTI]

-Stokes . . . . . . . . . . . . . 28 D. NEK5000 . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 E. Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 F. Mesh Generation . . . . . . . . . . . . . . . . . . . . . . . 36 III RESULTS AND DISCUSSION... in consumer vehicles and creating faster commercial jets. While discovering new energy resources in itself is an important concept, the rate of energy consumption, or power, is perhaps equally important. Power generation is what drives the modern world...

Camp, Joshua Lane

2012-07-16T23:59:59.000Z

123

Large-eddy simulation of evaporating spray in a coaxial combustor  

E-Print Network [OSTI]

on unstructured grids at conditions representative of gas-turbine combustors. ? 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.

124

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

E-Print Network [OSTI]

combustion engines, liquid and solid propellant rocket motors, gas-turbine aircraft engines, International. In gas turbine combustors, for example, the liquid fuel jet undergoes primary and secondary atomization on structured grids and do not lend themselves applicable to the complex geometries of engineering gas-turbine

Apte, Sourabh V.

125

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

126

Large eddy simulation for predicting turbulent heat transfer in gas turbines  

Science Journals Connector (OSTI)

...predicting turbulent heat transfer in gas turbines Danesh K. Tafti Long He K. Nagendra...of propulsion and power generation gas turbines. Accurate prediction of blade metal...compressed bypass air and allow higher turbine inlet temperature, increasing fuel efficiency...

2014-01-01T23:59:59.000Z

127

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

128

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

Broader source: Energy.gov [DOE]

2009 DOE Hydrogen Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting, May 18-22, 2009 -- Washington D.C.

129

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

E-Print Network [OSTI]

inside a SCRAMJET combustor, ignition and flame-holding capabilities are critical to the development-fueled SCRAMJET engine for Mach 6 flight condition. Following a LES approach, Lavante et al.4 succeed to recover

Paris-Sud XI, Université de

130

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

131

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

Broader source: Energy.gov [DOE]

2010 DOE Vehicle Technologies and Hydrogen Programs Annual Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C.

132

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

133

The emerging role of large eddy simulation in industrial practice: challenges and opportunities  

Science Journals Connector (OSTI)

...author over recent years. Particular...spoiler. In Advances in hybrid...43rd AIAA Aerospace Sciences Meeting and...eds) 2008 Advances in hybrid...approach. In Advances in DNS/LES...AIAA 39th Aerospace Science Meeting...

2009-01-01T23:59:59.000Z

134

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

135

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

136

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

137

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

138

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

139

Large-eddy Simulation of the Nighttime Stable Atmospheric Boundary Layer  

E-Print Network [OSTI]

Emissions from Landfills". Submitted to Environmentalflow rate on top of the landfill from 1400 LST onwards. Toplume dispersion over a landfill and good results are

Zhou, Bowen

2012-01-01T23:59:59.000Z

140

Large eddy simulation for predicting turbulent heat transfer in gas turbines  

Science Journals Connector (OSTI)

...wall functions|ribbed duct| 1. Background Gas turbine technology plays a critical role in civilian as well as...generation. One of the key challenges in the development of advanced gas turbines is effective thermal management in the high-pressure...

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.


141

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"

142

Performance of an Eddy DiffusivityMass Flux Scheme for Shallow Cumulus Boundary Layers  

Science Journals Connector (OSTI)

Comparisons between single-column (SCM) simulations with the total energymass flux boundary layer scheme (TEMF) and large-eddy simulations (LES) are shown for four cases from the Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) ...

Wayne M. Angevine; Hongli Jiang; Thorsten Mauritsen

2010-07-01T23:59:59.000Z

143

Vermont Yankee simulator qualification: large-break LOCA  

SciTech Connect (OSTI)

Yankee Atomic Electric Company (YAEC) has developed simulator benchmark capabilities for the Seabrook, Maine Yankee, and Vermont Yankee Nuclear Power Station (VYNPS) simulators. The goal is to establish that each simulator has a satisfactory real-time response for different scenarios that will enhance operator training. Vermont Yankee purchased a full-scope plane simulator for the VYNPS, a four-unit boiling water reactor with a Mark-I containment. The following seven benchmark cases were selected by YAEC and VYNPC to supplement the Simulator Acceptance Test Program: (1) control rod swap; (2) partial reactor scram; (3) recirculation pump trip; (4) main steam isolation valve (MSIV) closure without scram, (5) main steamline break, (6) small-break loss-of-coolant accident (LOCA), and (7) large-break LOCA. Five simulator benchmark sessions have been completed. Each session identified simulator capabilities and limitations that needed correction. This paper discusses results from the latest large-break LOCA case.

Loomis, J.N.; Fernandez, R.T.

1987-01-01T23:59:59.000Z

144

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

145

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

146

Transient simulation for large scale flow in bubble columns  

Science Journals Connector (OSTI)

Abstract The transient simulation of large scale bubbly flow in bubble columns using the unsteady Reynolds averaged Navier Stokes (URANS) equations is investigated in the present paper. An extensive set of bubble forces is used with different models for the bubble induced turbulence. Criteria are given to assess the independence of the simulation time and the time step length. Using these criteria it is shown that a simulation time, time step length and mesh independent solution can be obtained for complex bubbly flows using URANS equations under certain requirements. With the obtained setup the contribution of the resolved turbulence to the total turbulence and the influence of the bubble induced turbulence modeling on the resolved turbulence is investigated. Further, it is pointed out that the virtual mass force is not negligible. The simulations are compared to data from the literature at two different superficial velocities, which cover monodisperse and polydisperse bubbly flows.

T. Ziegenhein; R. Rzehak; D. Lucas

2015-01-01T23:59:59.000Z

147

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

148

Advanced coal gasifier designs using large-scale simulations  

SciTech Connect (OSTI)

Porting of the legacy code MFIX to a high performance computer (HPC) and the use of high resolution simulations for the design of a coal gasifier are described here. MFIX is based on a continuum multiphase flow model that considers gas and solids to form interpenetrating continua. Low resolution simulations of a commercial scale gasifier with a validated MFIX model revealed interesting physical phenomena with implications on the gasifier design, which prompted the study reported here. To be predictive, the simulations need to model the spatiotemporal variations in gas and solids volume fractions, velocities, temperatures with any associated phase change and chemical reactions. These processes occur at various time- and length-scales requiring very high spatial resolution and large number of iterations with small time-steps. We were able to perform perhaps the largest known simulations of gas-solids reacting flows, providing detailed information about the gas-solids flow structure and the pressure, temperature and species distribution in the gasifier. One key finding is the new features of the coal jet trajectory revealed with the high spatial resolution, which provides information on the accuracy of the lower resolution simulations. Methodologies for effectively combining high and low resolution simulations for design studies must be developed. From a computational science perspective, we found that global communication has to be reduced to achieve scalability to 1000s of cores, hybrid parallelization is required to effectively utilize the multicore chips, and the wait time in the batch queue significantly increases the actual time-to-solution. From our experience, development is required in the following areas: efficient solvers for heterogeneous, massively parallel systems; data analysis tools to extract information from large data sets; and programming environments for easily porting legacy codes to HPC.

Syamlal, M [National Energy Technology Laboratory (NETL); Guenther, Chris [National Energy Technology Laboratory (NETL); Gel, Aytekin [Aeolus Research Inc.; Pannala, Sreekanth [ORNL

2009-01-01T23:59:59.000Z

149

Eddie Bernice Johnson | Department of Energy  

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

Eddie Bernice Johnson About Us Eddie Bernice Johnson, (D-TX) - Congresswoman Representing the 30th District of Texas Eddie Bernice Johnson Congresswoman Eddie Bernice Johnson is...

150

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

151

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

152

Big Eddy-Knight  

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

(PDCI) Upgrade Project Whistling Ridge Energy Project Line Rebuild, Relocation and Substation Projects Wind Projects Big Eddy-Knight Transmission Project BPA has decided to...

153

Simulation of Turbulent Flow Inside and Above Wind Farms: Model Validation and Layout Effects  

Science Journals Connector (OSTI)

A recently-developed large-eddy simulation framework is validated and used to investigate turbulent flow within and above wind farms under neutral conditions. Two different layouts are considered, consisting of t...

Yu-Ting Wu; Fernando Port-Agel

2013-02-01T23:59:59.000Z

154

Cosmological Simulations for Large-Scale Sky Surveys | Argonne Leadership  

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

Instantaneous velocity magnitude in a flow through an open valve in a valve/piston assembly. Instantaneous velocity magnitude in a flow through an open valve in a valve/piston assembly. Instantaneous velocity magnitude in a flow through an open valve in a valve/piston assembly. Christos Altantzis, MIT, and Martin Schmitt, LAV. All the images were generated from their work at LAV. Cosmological Simulations for Large-Scale Sky Surveys PI Name: Christos Frouzakis PI Email: frouzakis@lav.mavt.ethz.ch Institution: Swiss Federal Institute of Technology Zurich Allocation Program: INCITE Allocation Hours at ALCF: 100 Million Year: 2014 Research Domain: Chemistry The combustion of coal and petroleum-based fuels supply most of the energy needed to meet the world's transportation and power generation demands. To address the anticipated petroleum shortage, along with increasing energy

155

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

156

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

157

Direct and Large-Eddy Simulation of Turbulent Flows on Composite Multi-Resolution Grids by the Lattice Boltzmann  

E-Print Network [OSTI]

by the Lattice Boltzmann Method Hatem Touil,1 Denis Ricot,2 and Emmanuel L´ev^eque1 1 Laboratoire de Physique de, the lattice Boltzmann method, originally designed for uniform structured grids, needs to be extended. The lattice Boltzmann scheme relies on the standard D3Q19 lattice in a cell-vertex representation, and uses

Paris-Sud XI, Université de

158

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

159

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

160

Large-eddy simulation of the plume generated by the fire at the Buncefield oil depot in December 2005  

Science Journals Connector (OSTI)

...generated by the Chisholm forest fire in Canada in 2001. It is possible that latent heating...means that very little of the incoming solar radiation is reflected. This is consistent...radiation in the atmosphere, short-wave (solar) and long-wave (terrestrial) radiation...

2009-01-01T23:59:59.000Z

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.


161

Under consideration for publication in J. Fluid Mech. 1 Large-eddy simulation of a bi-periodic  

E-Print Network [OSTI]

the hot products. However, the application of transpiration-based technology to gas turbines is impossible In gas turbines, the solid parts such as the turbine blades or the liner of the combustion chamber 2600. The numerical results for this fully developed, bi-periodic turbulent flow with effusion

Nicoud, Franck

162

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

E-Print Network [OSTI]

, L. Vervisch, P. Domingo, Combust. Flame 146 (2006), 635-648. 28. S. Navarro-Martinez, A. Kronenburg, F.D. Mare, Flow Turbul. Combust. 75 (2005), 245-274. 29. A. Triantafyllidis, E. Mastorakos, Flow Turbul. Combust. 84 (2010), 481-512. 30. M...

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

2014-06-25T23:59:59.000Z

163

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

164

Dynamical and Microphysical Evolution during Mixed-Phase Cloud Glaciation Simulated Using the Bulk Adaptive Habit Prediction Model  

Science Journals Connector (OSTI)

A bulk microphysics scheme predicting ice particle habit evolution has been implemented in the Weather Research and Forecasting Model. Large-eddy simulations are analyzed to study the effects of ice habit and number concentration on the bulk ice ...

Kara J. Sulia; Hugh Morrison; Jerry Y. Harrington

2014-11-01T23:59:59.000Z

165

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

166

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

167

Energy Flux to a Cyclonic Eddy off Cabo Frio, Brazil  

Science Journals Connector (OSTI)

To evaluate the energy flux from the mean flow of South Atlantic western boundary currents toward typical Cabo Frio eddies (at Brazilian southeast coast), the southwestern Atlantic circulation was simulated with the Princeton Ocean Model. ...

Manlio F. Mano; Afonso M. Paiva; Audalio R. Torres Jr.; Alvaro L. G. A. Coutinho

2009-11-01T23:59:59.000Z

168

Two-dimensional simulations of extreme floods on a large watershed  

E-Print Network [OSTI]

Two-dimensional simulations of extreme floods on a large watershed John F. England Jr. a,*, Mark L-dimensional, Runoff, Erosion and Export (TREX) model to simulate extreme floods on large watersheds in semi, validation and simulation of extreme storms and floods on the 12,000 km2 Arkansas River watershed above

Julien, Pierre Y.

169

Large-scale simulations on multiple Graphics Processing Units (GPUs) for the direct simulation Monte Carlo method  

Science Journals Connector (OSTI)

In this study, the application of the two-dimensional direct simulation Monte Carlo (DSMC) method using an MPI-CUDA parallelization paradigm on Graphics Processing Units (GPUs) clusters is presented. An all-device (i.e. GPU) computational approach is ... Keywords: Graphics Processing Unit (GPU), MPI-CUDA, Parallel direct simulation Monte Carlo, Rarefied gas dynamics, Very large-scale simulation

C. -C. Su; M. R. Smith; F. -A. Kuo; J. -S. Wu; C. -W. Hsieh; K. -C. Tseng

2012-10-01T23:59:59.000Z

170

High-Frequency Transient Eddies and Blocking  

Science Journals Connector (OSTI)

In this paper we investigate the role of high-frequency transient eddies in the maintenance of the blocking high which occurred over Europe on 16-25 February 1979. Time-filtering is used to decompose the atmospheric large-scale flow into ...

Eero Holopainen; Carl Fortelius

1987-06-01T23:59:59.000Z

171

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

E-Print Network [OSTI]

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

Shue, Nai-Shen

2012-01-01T23:59:59.000Z

172

Spice simulation of a large-signal model for quantum cascade laser  

Science Journals Connector (OSTI)

A large-signal spice model of QCL is described, which is based on a set of rate equations. This model can also perform both small- and large-signal simulations. The dynamic responses obtained by using Spice si...

Gui Chu Chen; Guang Han Fan; Shu Ti Li

2008-07-01T23:59:59.000Z

173

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

174

A Case Study of Radar Observations and WRF LES Simulations of the Impact of Ground-Based Glaciogenic Seeding on Orographic Clouds and Precipitation. Part I: Observations and Model Validations  

Science Journals Connector (OSTI)

Profiling airborne radar data and accompanying large-eddy-simulation (LES) modeling are used to examine the impact of ground-based glaciogenic seeding on cloud and precipitation in a shallow stratiform orographic winter storm. This storm occurred ...

Xia Chu; Lulin Xue; Bart Geerts; Roy Rasmussen; Daniel Breed

2014-10-01T23:59:59.000Z

175

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

176

Adaptive Optics Simulations for the European Extremely Large Telescope  

E-Print Network [OSTI]

Louarn, Sylvain Oberti, and A. Garcia-Rissman European Southern Observatory, Karl-Schwarzschild-Stra?e 2 large telescopes (ELTs) of primary mirror diameters 20-42 m are in the design stages, such as the thirty of view (FOV) with a single deformable mirror (DM). Due to the sky coverage constraints of NGS systems

Liske, Jochen

177

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

178

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

179

GridMate: A Portable Simulation Environment for Large-Scale Adaptive Scientific Applications  

E-Print Network [OSTI]

GridMate: A Portable Simulation Environment for Large-Scale Adaptive Scientific Applications: parashar@caip.rutgers.edu Abstract--In this paper, we present a portable sim- ulation environment GridMate for large-scale adaptive scientific applications in multi-site Grid environments. GridMate is a discrete

Li, Xiaolin "Andy"

180

A vectorial DEVS extension for large scale system modeling and parallel simulation  

Science Journals Connector (OSTI)

In this article we introduce an extension to the Discrete Event System (DEVS) formalism called Vectorial DEVS (VECDEVS) that allows to represent large scale systems in a graphic block diagram way. A pure VECDEVS model basically consist in an array of ... Keywords: DEVS, large scale modeling, load balancing, parallel simulation

Federico Bergero, Ernesto Kofman

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.


181

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

182

NAMD - The Engine for Large-Scale Classical MD Simulations of Biomolecular  

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

NAMD NAMD NAMD - The Engine for Large-Scale Classical MD Simulations of Biomolecular Systems Based on a Polarizable Force Field PI Name: Benoit Roux PI Email: roux@uchicago.edu Institution: Argonne National Laboratory & University of Chicago Allocation Program: ESP Allocation Hours at ALCF: 80 Million Year: 2010 to 2013 Research Domain: Biological Sciences Biology, at the atomic and molecular level, is governed by complex interactions involving a large number of key constituents, including water, ions, proteins, nucleic acids, and lipid membranes. The goal of this project is to develop new technologies to simulate virtual models of biomolecular systems with an unprecedented accuracy. Large-scale molecular dynamics (MD) simulations based on atomic models play an increasingly

183

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

E-Print Network [OSTI]

for large facilities with multiple buildings, however, has been relatively rare. Due to the immense size of certain facilities such as college campuses and correctional institutes, simulating energy consumption for the entire campus and reporting... Office Building", Oak Ridge National Laboratory, OFWL Report No. ORNLICON-363, Oak Ridge, TN. SAS Institute, Inc. 1990. "SASISTAT User's Guide", Cary, NC, Ver. 6,4th ed., Vol. 2. Torres-Nunci, N. 1989. "Simulation Modeling Energy Consumption...

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

1996-01-01T23:59:59.000Z

184

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

185

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.

186

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

187

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.

188

Next: effect of eddies on the Hadley circulation We talked about ways to incorporate eddy heat fluxes  

E-Print Network [OSTI]

Next: effect of eddies on the Hadley circulation We talked about ways to incorporate eddy heat ¡ An eddy-driven Hadley cell model #12;Effect of eddy fluxes Compare the dry dynamical core model run axisymmetrically versus with eddies ¡ Hadley cell is significantly stronger with eddies ¡ Suggests eddies

Frierson, Dargan

189

Large-scale Simulation of the Two-dimensional Kinetic Ising Model  

E-Print Network [OSTI]

Large-scale Simulation of the Two-dimensional Kinetic Ising Model Andreas Linke, Dieter W. Heermann-dimensional kinetic Ising model using a lattice of size 106 106 spins. We used Glauber as well as Metropolis dynamics for the Ising model because of its simplicity and its model character as a representant for a universality class

Heermann, Dieter W.

190

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

191

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

E-Print Network [OSTI]

Environmental, aesthetic and political pressures continue to push for siting offshore wind turbines beyond sightSimulation of large-amplitude motion of floating wind turbines using conservation of momentum Lei equations of motion (EOMs) of a floating wind turbine system using the theorem of conservation of angular

Sweetman, Bert

192

iTETRIS: A modular simulation platform for the large scale evaluation of cooperative ITS applications  

Science Journals Connector (OSTI)

Cooperative ITS systems are expected to improve road traffic safety and efficiency, and provide infotainment services on the move, through the dynamic exchange of messages between vehicles, and between vehicles and infrastructure nodes. The complexity of cooperative ITS systems and the interrelation between its components requires their extensive testing before deployment. The lack of simulation platforms capable to test, with high modelling accuracy, cooperative ITS systems and applications in large scale scenarios triggered the implementation of the EU-funded iTETRIS simulation platform. iTETRIS is a unique open source simulation platform characterized by a modular architecture that allows integrating two widely adopted traffic and wireless simulators, while supporting the implementation of cooperative ITS applications in a language-agnostic fashion. This paper presents in detail the iTETRIS simulation platform, and describes its architecture, standard compliant implementation, operation and new functionalities. Finally, the paper demonstrates iTETRIS large scale cooperative ITS evaluation capabilities through the implementation and evaluation of cooperative traffic congestion detection and bus lane management applications. The detailed description and implemented examples provide valuable information on how to use and exploit iTETRIS simulation potential.

Michele Rondinone; Julen Maneros; Daniel Krajzewicz; Ramon Bauza; Pasquale Cataldi; Fatma Hrizi; Javier Gozalvez; Vineet Kumar; Matthias Rckl; Lan Lin; Oscar Lazaro; Jrmie Leguay; Jrme Hrri; Sendoa Vaz; Yoann Lopez; Miguel Sepulcre; Michelle Wetterwald; Robbin Blokpoel; Fabio Cartolano

2013-01-01T23:59:59.000Z

193

Impact of Variable-Resolution Meshes on Midlatitude Baroclinic Eddies Using CAM-MPAS-A  

Science Journals Connector (OSTI)

The effects of a variable-resolution mesh on simulated midlatitude baroclinic eddies in idealized settings are examined. Both aquaplanet and HeldSuarez experiments are performed using the Model for Prediction Across Scales-Atmosphere (MPAS-A) ...

Sara A. Rauscher; Todd D. Ringler

2014-11-01T23:59:59.000Z

194

Impacts on ocean heat from transient mesoscale eddies in a hierarchy of climate models  

Science Journals Connector (OSTI)

We characterize impacts on heat in the ocean climate system from transient ocean mesoscale eddies. Our tool is a suite of centennial-scale 1990 radiatively forced numerical climate simulations from three GFDL coupled models comprising the CM2-O ...

Stephen M. Griffies; Michael Winton; Whit G. Anderson; Rusty Benson; Thomas L. Delworth; Carolina O. Dufour; John P. Dunne; Paul Goddard; Adele k. Morrison; Anthony Rosati; Andrew T. Wittenberg; Jianjun Yin; Rong Zhang

195

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

196

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 systems 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

197

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

198

Large-scale Validation of AMIP II Land-surface Simulations: Preliminary Results for Ten Models  

SciTech Connect (OSTI)

This report summarizes initial findings of a large-scale validation of the land-surface simulations of ten atmospheric general circulation models that are entries in phase II of the Atmospheric Model Intercomparison Project (AMIP II). This validation is conducted by AMIP Diagnostic Subproject 12 on Land-surface Processes and Parameterizations, which is focusing on putative relationships between the continental climate simulations and the associated models' land-surface schemes. The selected models typify the diversity of representations of land-surface climate that are currently implemented by the global modeling community. The current dearth of global-scale terrestrial observations makes exacting validation of AMIP II continental simulations impractical. Thus, selected land-surface processes of the models are compared with several alternative validation data sets, which include merged in-situ/satellite products, climate reanalyses, and off-line simulations of land-surface schemes that are driven by observed forcings. The aggregated spatio-temporal differences between each simulated process and a chosen reference data set then are quantified by means of root-mean-square error statistics; the differences among alternative validation data sets are similarly quantified as an estimate of the current observational uncertainty in the selected land-surface process. Examples of these metrics are displayed for land-surface air temperature, precipitation, and the latent and sensible heat fluxes. It is found that the simulations of surface air temperature, when aggregated over all land and seasons, agree most closely with the chosen reference data, while the simulations of precipitation agree least. In the latter case, there also is considerable inter-model scatter in the error statistics, with the reanalyses estimates of precipitation resembling the AMIP II simulations more than to the chosen reference data. In aggregate, the simulations of land-surface latent and sensible heat fluxes appear to occupy intermediate positions between these extremes, but the existing large observational uncertainties in these processes make this a provisional assessment. In all selected processes as well, the error statistics are found to be sensitive to season and latitude sector, confirming the need for finer-scale analyses which also are in progress.

Phillips, T J; Henderson-Sellers, A; Irannejad, P; McGuffie, K; Zhang, H

2005-12-01T23:59:59.000Z

199

Oceanic mass transport by mesoscale eddies  

Science Journals Connector (OSTI)

...time-mean ocean circulation transports fluid as a conveyor belt, but fluid parcels can also be trapped and transported discretely...continuously, mesoscale eddies can trap fluid parcels within the eddy core and transport them discretely...

Zhengguang Zhang; Wei Wang; Bo Qiu

2014-07-18T23:59:59.000Z

200

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

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.


201

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

202

Simulating flow separation from continuous surfaces: routes to overcoming the Reynolds number barrier  

Science Journals Connector (OSTI)

...exposition given in a recent paper by Tessicini et...LES. In Proc. 40th Aerospace Sciences Meeting, Reno, NV...large-eddy simulations. In Advances in turbulence R. Benzi1995pp...LES approach. In Advances in DNS/LES, 1st AFOSR...

2009-01-01T23:59:59.000Z

203

Nek5000 Ready to Use after Simulations of Important Pipe Flow Benchmark |  

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

Nek5000 Ready to Use after Simulations of Important Pipe Flow Nek5000 Ready to Use after Simulations of Important Pipe Flow Benchmark Nek5000 Ready to Use after Simulations of Important Pipe Flow Benchmark January 29, 2013 - 1:42pm Addthis Velocity magnitude in MATiS-H spacer grid with swirl-type vanes. Velocity magnitude in MATiS-H spacer grid with swirl-type vanes. As part of the on-going Nek5000 validation efforts, a series of large eddy simulations (LES) have been performed for thermal stratification in a pipe. Results were in good agreement with the experiment and the simulation data has provided insight into the physics of the flow. An additional series of simulations of the OECD-NEA MATiS-H benchmark has also been completed using intermediate- fidelity modeling approaches, such as k-epsilon, k-omega shear stress transport, and ID detached eddy simulation, as well as one

204

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

205

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

206

Eddy-Current-Induced Multipole Field Calculations  

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

Eddy-Current-Induced Multipole Field Calculations Eddy-Current-Induced Multipole Field Calculations September 29, 2003 1 Eddy-Current-Induced Multipole Field Calculations Nicholas S. Sereno, Suk H. Kim 1.0 Abstract Time-varying magnetic fields of magnets in booster accelerators induce substantial eddy currents in the vacuum chambers. The eddy currents in turn act to produce various multi- pole fields that act on the beam. These fields must be taken into account when doing a lat- tice design. In the APS booster, the relatively long dipole magnets (3 meters) are linearly ramped to accelerate the injected 325 MeV beam to 7 GeV. Substantial dipole and sextu- pole fields are generated in the elliptical vacuum chamber from the induced eddy currents. In this note, formulas for the induced dipole and sextupole fields are derived for elliptical and rectangular vacuum chambers for a time-varying dipole field. A discussion is given

207

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

208

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

209

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

210

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

211

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

E-Print Network [OSTI]

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 simulations of physical and chemical processes within a diesel engine remain a challenge due to the many

Im, Hong G.

212

PC-Based Modeling and Simulation of Large Marine Propulsion Plant  

Science Journals Connector (OSTI)

At present, most of marine engine room simulators (MERS) in the ... So a simulation system of a PC-Based marine propulsion plant has been developed for training. In ... paper, a transient simulation model for lar...

Sun Jianbo; Guo Chen

2010-01-01T23:59:59.000Z

213

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

214

Measurement and simulation of swirling coal combustion  

Science Journals Connector (OSTI)

Particle image velocimetry (PIV), thermocouples and flue gas analyzer are used to study swirling coal combustion and NO formation under different secondary-air ratios. EulerianLagrangian large-eddy simulation (LES) using the SmagorinskyLilly sub-grid scale stress model, presumed-PDF fast chemistry and eddy-break-up (EBU) gas combustion models, particle devolatilization and particle combustion models, are simultaneously used to simulate swirling coal combustion. Statistical LES results are validated by measurement results. Instantaneous LES results show that the coherent structures for swirling coal combustion are stronger than those for swirling gas combustion. Particles are shown to concentrate along the periphery of the coherent structures. Combustion flame is located in the high vorticity and high particle concentration zones. Measurement shows that secondary-air ratios have little effect on final NO formation at the exit of the combustor.

Liyuan Hu; Lixing Zhou; Yonghao Luo; Caisong Xu

2013-01-01T23:59:59.000Z

215

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

2012-06-07T23:59:59.000Z

216

Department of Energy Awards Eddy/Lea Regional Commission $300...  

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

Department of Energy Awards EddyLea Regional Commission 300,000 Grant Department of Energy Awards EddyLea Regional Commission 300,000 Grant Department of Energy Awards EddyLea...

217

Lagrangian study of transport and mixing in a mesoscale eddy street  

E-Print Network [OSTI]

We use dynamical systems approach and Lagrangian tools to study surface transport and mixing of water masses in a selected coastal region of the Japan Sea with moving mesoscale eddies associated with the Primorskoye Current. Lagrangian trajectories are computed for a large number of particles in an interpolated velocity field generated by a numerical regional multi-layer eddy-resolving circulation model. We compute finite-time Lyapunov exponents for a comparatively long period of time by the method developed and plot the Lyapunov synoptic map quantifying surface transport and mixing in that region. This map uncovers the striking flow structures along the coast with a mesoscale eddy street and repelling material lines. We propose new Lagrangian diagnostic tools --- the time of exit of particles off a selected box, the number of changes of the sign of zonal and meridional velocities --- to study transport and mixing by a pair of strongly interacting eddies often visible at sea-surface temperature satellite imag...

Prants, S V; Ponomarev, V I; Uleysky, M Yu; 10.1016/j.ocemod.2011.02.008

2012-01-01T23:59:59.000Z

218

Microsoft Word - EddyLea20020828.doc  

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

00,000 00,000 to Eddy/Lea Regional Commission Community Reuse Organization WASHINGTON, D.C. - The Department of Energy (DOE) has awarded $400,000 in the form of two competitive grants to the Eddy/Lea Regional Commission. The Eddy/Lea Regional Commission is the community reuse organization (CRO) serving the Department's Waste Isolation Pilot Plant (WIPP) in Carlsbad, New Mexico. The Energy Department is a good neighbor to the communities surrounding our sites, Secretary of Energy Spencer Abraham said. "We will continue to work with Eddy/Lea Regional Commission and other community reuse organizations around the country, to retain, expand or create jobs for workers affected by restructuring efforts." The Eddy/Lea Regional Commission applied for funding from the department's Office of Worker

219

Large scale simulations of solar type III radio bursts: flux density, drift rate, duration and bandwidth  

E-Print Network [OSTI]

Non-thermal electrons accelerated in the solar corona can produce intense coherent radio emission, known as solar type III radio bursts. This intense radio emission is often observed from hundreds of MHz in the corona down to the tens of kHz range in interplanetary space. It involves a chain of physical processes from the generation of Langmuir waves to nonlinear processes of wave-wave interaction. We develop a self-consistent model to calculate radio emission from a non-thermal electron population over large frequency range, including the effects of electron transport, Langmuir wave-electron interaction, the evolution of Langmuir waves due to non-linear wave-wave interactions, Langmuir wave conversion into electromagnetic emission, and finally escape of the electromagnetic waves. For the first time we simulate escaping radio emission over a broad frequency range from 500~MHz down to a few MHz and infer key properties of the radio emission observed: the onset (starting) frequency, {identification as fundament...

Ratcliffe, H; Reid, H A S

2014-01-01T23:59:59.000Z

220

Recent results and future challenges for large scale Particle-In-Cell simulations of plasma-based accelerator concepts  

SciTech Connect (OSTI)

The concept and designs of plasma-based advanced accelerators for high energy physics and photon science are modeled in the SciDAC COMPASS project with a suite of Particle-In-Cell codes and simulation techniques including the full electromagnetic model, the envelope model, the boosted frame approach and the quasi-static model. In this paper, we report the progress of the development of these models and techniques and present recent results achieved with large-scale parallel PIC simulations. The simulation needs for modeling the plasma-based advanced accelerator at the energy frontier is discussed and a path towards this goal is outlined.

Huang, C.; An, W.; Decyk, V.K.; Lu, W.; Mori, W.B.; Tsung, F.S.; Tzoufras, M.; Morshed, S.; Antomsen, T.; Feng, B.; Katsouleas, T; Fonseca, R.A.; Martins, S.F.; Vieira, J.; Silva, L.O.; Geddes, C.G.R.; Cormier-Michel, E; Vay, J.-L.; Esarey, E.; Leemans, W.P.; Bruhwiler, D.L.; Cowan, B.; Cary, J.R.; Paul, K.

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

Lagrangian study of transport and mixing in a mesoscale eddy street  

E-Print Network [OSTI]

We use dynamical systems approach and Lagrangian tools to study surface transport and mixing of water masses in a selected coastal region of the Japan Sea with moving mesoscale eddies associated with the Primorskoye Current. Lagrangian trajectories are computed for a large number of particles in an interpolated velocity field generated by a numerical regional multi-layer eddy-resolving circulation model. We compute finite-time Lyapunov exponents for a comparatively long period of time by the method developed and plot the Lyapunov synoptic map quantifying surface transport and mixing in that region. This map uncovers the striking flow structures along the coast with a mesoscale eddy street and repelling material lines. We propose new Lagrangian diagnostic tools --- the time of exit of particles off a selected box, the number of changes of the sign of zonal and meridional velocities --- to study transport and mixing by a pair of strongly interacting eddies often visible at sea-surface temperature satellite images in that region. We develop a technique to track evolution of clusters of particles, streaklines and material lines. The Lagrangian tools used allow us to reveal mesoscale eddies and their structure, to track different phases of the coastal flow, to find inhomogeneous character of transport and mixing on mesoscales and submesoscales and to quantify mixing by the values of exit times and the number of times particles wind around the eddy's center.

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

2012-02-02T23:59:59.000Z

222

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

223

Rotating concave eddy current probe  

DOE Patents [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

224

Using Cloud-Resolving Model Simulations of Deep Convection to Inform Cloud Parmaterizations in Large-Scale Models  

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

Using Cloud-Resolving Model Simulations Using Cloud-Resolving Model Simulations of Deep Convection to Inform Cloud Parameterizations in Large-Scale Models S. A. Klein National Oceanic and Atmospheric Administration Geophysical Fluid Dynamics Laboratory Princeton, New Jersey R. Pincus National Oceanic and Atmospheric Administration Cooperative Institute for Research in Environmental Science Climate Diagnostics Center Boulder, Colorado K. -M. Xu National Aeronautics and Space Administration Langley Research Center Hampton, Virginia Abstract 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

225

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

226

Modeling and Simulation of Advanced Nano-Scale Very Large Scale Integration Circuits  

E-Print Network [OSTI]

is one level beyond simulation and modeling to directly optimize design, but is also built upon accurate simulations and modeling. Two simple, yet efficient, buffering and gate sizing techniques are presented. On 20 industrial designs in 45nm and 65nm...

Zhou, Ying

2010-07-14T23:59:59.000Z

227

Microsoft Word - Big Eddy ROD.doc  

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

Administration's Administration's Big Eddy-Knight Transmission Project Record of Decision September 2011 Decision The Bonneville Power Administration (BPA) has decided to construct the Big Eddy-Knight Transmission Project in Wasco County, Oregon and Klickitat County, Washington. As described in the Big Eddy-Knight Transmission Project Final Environmental Impact Statement (EIS) (DOE/EIS-0421, July 2011), this project consists primarily of constructing a new, approximately 28-mile-long, 500-kilovolt (kV) transmission line and ancillary facilities between BPA's existing Big Eddy Substation in The Dalles, Oregon, to a proposed new Knight Substation that will be connected to an existing BPA line about 4 miles northwest of Goldendale, Washington. For the

228

Big Eddy-Knight Transmission Project  

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

BPA's existing Big Eddy Substation in The Dalles, Oregon, to a proposed new Knight Substation that would be connected to an existing BPA line about 4 miles northwest of...

229

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

230

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

231

Visualizing a Large-Scale Structure of Production Network by N-Body Simulation  

Science Journals Connector (OSTI)

......forming specialized production flows. An example...Air-Water Industrial Gas (17/18), Kyowa...Large-Scale Structure of Production Network 171 4...the computational cost is largest for the...the calculation cost being preferred...Large-Scale Structure of Production Network 173 Fig......

Yoshi Fujiwara

2009-03-01T23:59:59.000Z

232

A Domain Decomposition Approach for Large-Scale Simulations of Flow Processes in Hydrate-Bearing Geologic Media  

SciTech Connect (OSTI)

Simulation of the system behavior of hydrate-bearing geologic media involves solving fully coupled mass- and heat-balance equations. In this study, we develop a domain decomposition approach for large-scale gas hydrate simulations with coarse-granularity parallel computation. This approach partitions a simulation domain into small subdomains. The full model domain, consisting of discrete subdomains, is still simulated simultaneously by using multiple processes/processors. Each processor is dedicated to following tasks of the partitioned subdomain: updating thermophysical properties, assembling mass- and energy-balance equations, solving linear equation systems, and performing various other local computations. The linearized equation systems are solved in parallel with a parallel linear solver, using an efficient interprocess communication scheme. This new domain decomposition approach has been implemented into the TOUGH+HYDRATE code and has demonstrated excellent speedup and good scalability. In this paper, we will demonstrate applications for the new approach in simulating field-scale models for gas production from gas-hydrate deposits.

Zhang, Keni; Moridis, G.J.; Wu, Y.-S.; Pruess, K.

2008-07-01T23:59:59.000Z

233

The mass and angular momentum distribution of simulated massive early-type galaxies to large radii  

Science Journals Connector (OSTI)

......simulated halo mass functions...discrepancy are strong wind-driving feedback...relations of mass with radius and stellar velocity dispersion...shows stellar mass enclosed within...we showed the velocity fields of three...Especially the maps in Fig.-8......

Xufen Wu; Ortwin Gerhard; Thorsten Naab; Ludwig Oser; Inma Martinez-Valpuesta; Michael Hilz; Eugene Churazov; Natalya Lyskova

2014-01-01T23:59:59.000Z

234

Advanced simulation of electron heat transport in fusion plasmas  

SciTech Connect (OSTI)

Electron transport in burning plasmas is more important since fusion products first heat electrons. First-principles simulations of electron turbulence are much more challenging due to the multi-scale dynamics of the electron turbulence, and have been made possible by close collaborations between plasma physicists and computational scientists. The GTC simulations of collisionless trapped electron mode (CTEM) turbulence show that the electron heat transport exhibits a gradual transition from Bohm to gyroBohm scaling when the device size is increased. The deviation from the gyroBohm scaling can be induced by large turbulence eddies, turbulence spreading, and non-diffusive transport processes. Analysis of radial correlation function shows that CTEM turbulence eddies are predominantly microscopic but with a significant tail in the mesoscale. A comprehensive analysis of kinetic and fluid time scales shows that zonal flow shearing is the dominant decorrelation mechanism. The mesoscale eddies result from a dynamical process of linear streamers breaking by zonal flows and merging of microscopic eddies. The radial profile of the electron heat conductivity only follows the profile of fluctuation intensity on a global scale, whereas the ion transport tracks more sensitively the local fluctuation intensity. This suggests the existence of a nondiffusive component in the electron heat flux, which arises from the ballistic radial E x B drift of trapped electrons due to a combination of the presence of mesoscale eddies and the weak de-tuning of the toroidal precessional resonance that drives the CTEM instability. On the other hand, the ion radial excursion is not affected by the mesoscale eddies due to a parallel decorrelation, which is not operational for the trapped electrons because of a bounce averaging process associated with the electron fast motion along magnetic field lines. The presence of the nondiffusive component raises question on the applicability of the usual quasilinear theory for the CTEM electron transport. This is in contrast to the good agreement between the quasilinear transport theory and simulation results of the electron heat transport in electron temperature gradient (ETG) turbulence, which is regulated by a wave-particle decorrelation. Therefore, the transport in the CTEM turbulence is a fluid-like eddy mixing process even though the linear CTEM instability is driven by a kinetic resonance. In contrast, a kinetic process dominates the transport in the ETG turbulence, which is characterized by macroscopic streamers.

Lin, Zhihong [University of California, Irvine; Xiao, Y. [University of California, Irvine; Klasky, Scott A [ORNL; Lofstead, J. [Georgia Institute of Technology

2009-01-01T23:59:59.000Z

235

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

236

Large-Scale Earthquake Simulation: Computational Seismology and Complex Engineering Systems  

Science Journals Connector (OSTI)

Methods commonly used to generate artificial ground histories can't deal with the complex interactions that occur during earthquakes including the seismic source and wave's path site conditions and the presence of the built environment. To address this problem researchers in Carnegie Mellon University's Quake Group have used high-performance computing to simulate earthquakes at regional scales including complex engineering systems.

Ricardo Taborda; Jacobo Bielak

2011-01-01T23:59:59.000Z

237

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

238

Finite element simulation of moisture movement and solute transport in a large caisson  

SciTech Connect (OSTI)

The results of the solute transport experiments performed on compacted, crushed Bandelier Tuff in caisson B of the experimental cluster described by DePoorter (1981) are simulated. Both one- and three-dimensional simulations of solute transport have been performed using two selected finite element codes. Results of bromide and iodide tracer experiments conducted during near-steady flow conditions have been analyzed for pulse additions made on December 6, 1984, and followed over a period of up to 60 days. In addition, a pulse addition of nonconservative strontium tracer on September 28, 1984, during questionably steady flow conditions has been analyzed over a period of 240 days. One-dimensional finite element flow and transport simulations were carried out assuming the porous medium to be homogeneous and the injection source uniformly distributed. To evaluate effects of the nonuniform source distribution and also to investigate effects of inhomogeneous porous medium properties, three dimensional finite element analyses of transport were carried out. Implications of the three-dimensional effects for the design and analysis of future tracer studies are discussed.

Huyakorn, P.S.; Jones, B.G.; Parker, J.C.; Wadsworth, T.D.; White, H.O. Jr.

1987-04-01T23:59:59.000Z

239

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.

240

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

Science Journals Connector (OSTI)

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

Xueli Luo; Christian Day; Horst Haas; Stylianos Varoutis

2011-01-01T23:59:59.000Z

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241

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

SciTech Connect (OSTI)

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

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

2011-07-15T23:59:59.000Z

242

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

243

Numerical simulation of nucleation scavenging within smoke plumes above large fires  

SciTech Connect (OSTI)

This paper presents preliminary results from an on-going smoke plume research project. The goal is to determine reasonable estimates of vertical distribution of smoke in the early post-nuclear-exchange environment, accounting for the air circulations forced by large, intense fires and for the possible prompt removal of smoke due to various scavenging mechanisms within pyrogenic clouds. These estimates may facilitate improved global-scale calculations by providing more accurate initial smoke distributions than have previously been available. Early results suggest that scavenging of smoke particles due to their activation as condensation nuclei may significantly reduce the amount of smoke available for climate modification. It appears that this scavenging process operates most efficiently in the smoke plumes which rise to the highest altitudes. Even if overseeding inhibits cloud droplet coalescence, rain may still form due to the collection of cloud droplets by very large aerosol particles.

Bradley, M.M.

1986-12-01T23:59:59.000Z

244

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

245

What is Bayesian statistics? Sean R. Eddy  

E-Print Network [OSTI]

What is Bayesian statistics? Sean R. Eddy Howard Hughes Medical Institute & Department of Genetics and Bayesian probability theory. The table game. Alice and Bob are playing a game in which the first one to six and Bob except who won each point. Clearly, the probability that Alice wins a point is the fraction

Eddy, Sean

246

Japan/East Sea Intrathermocline Eddies  

Science Journals Connector (OSTI)

Intrathermocline eddies (ITE) with diameters of 100 km and of thickness greater than 100 m are observed within each of the three quasi-stationary meanders of the Tsushima Current of the Japan/East Sea. Within the ITE homogenous, anticyclonic ...

Arnold L. Gordon; Claudia F. Giulivi; Craig M. Lee; Heather Hunt Furey; Amy Bower; Lynne Talley

2002-06-01T23:59:59.000Z

247

A Parallel Tree code for large Nbody simulation: dynamic load balance and data distribution on CRAY T3D system  

E-Print Network [OSTI]

N-body algorithms for long-range unscreened interactions like gravity belong to a class of highly irregular problems whose optimal solution is a challenging task for present-day massively parallel computers. In this paper we describe a strategy for optimal memory and work distribution which we have applied to our parallel implementation of the Barnes & Hut (1986) recursive tree scheme on a Cray T3D using the CRAFT programming environment. We have performed a series of tests to find an " optimal data distribution " in the T3D memory, and to identify a strategy for the " Dynamic Load Balance " in order to obtain good performances when running large simulations (more than 10 million particles). The results of tests show that the step duration depends on two main factors: the data locality and the T3D network contention. Increasing data locality we are able to minimize the step duration if the closest bodies (direct interaction) tend to be located in the same PE local memory (contiguous block subdivison, high granularity), whereas the tree properties have a fine grain distribution. In a very large simulation, due to network contention, an unbalanced load arises. To remedy this we have devised an automatic work redistribution mechanism which provided a good Dynamic Load Balance at the price of an insignificant overhead.

U. Becciani; R. Ansaloni; V. Antonuccio-Delogu; G. Erbacci; M. Gambera; A. Pagliaro; -

1997-09-02T23:59:59.000Z

248

Simulation study of the interaction between large-amplitude HF radio waves and the ionosphere  

E-Print Network [OSTI]

The time evolution of a large-amplitude electromagnetic (EM) wave injected vertically into the overhead ionosphere is studied numerically. The EM wave has a carrier frequency of 5 MHz and is modulated as a Gaussian pulse with a width of ca 0.1 milliseconds and a vacuum amplitude of 1.5 V/m. The pulse is propagated through the neutral atmosphere to the critical points of the magnetosphere where the ordinary (O) and extraordinary (X) modes are reflected, and back to the neutral atmosphere. We observe mode conversion of the O mode to electrostatic waves, as well as harmonic generation at the turning points of both the X and O modes, where their amplitudes rise to several times the original ones. The study has relevance for ionospheric interaction experiments in combination with ground-based and satellite or rocket observations.

Eliasson, B; Eliasson, Bengt; Thid\\'e, Bo

2006-01-01T23:59:59.000Z

249

Assessment of eddy current effects on compression experiments in the TFTR tokamak  

SciTech Connect (OSTI)

The eddy current induced on the TFTR vacuum vessel during compression experiments is estimated based on a cylindrical model. It produces an error magnetic field that generates magnetic islands at the rational magnetic surfaces. The widths of these islands are calculated and found to have some effect on electron energy confinement. However, resistive MHD simulation results indicate that the island formation process can be slowed down by plasma rotation.

Wong, K.L.; Park, W.

1986-05-01T23:59:59.000Z

250

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

251

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

252

INNOVATIVE EDDY CURRENT PROBE FOR MICRO DEFECTS  

SciTech Connect (OSTI)

This paper reports the development of an innovative eddy current (EC) probe, and its application to micro-defects on the root of the Friction Stir Welding (FSW). The new EC probe presents innovative concept issues, allowing 3D induced current in the material, and a lift-off independence. Validation experiments were performed on aluminium alloys processed by FSW. The results clearly show that the new EC probe is able to detect and sizing surface defects about 60 microns depth.

Santos, Telmo G.; Vilaca, Pedro; Quintino, Luisa [IDMEC, Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Santos, Jorge dos [GKSS, Max-Planck-Street 1, D-21502 Geesthacht (Germany); Rosado, Luis [IST, UTL, Av. Rovisco Pais, 1049-001 Lisbon (Portugal)

2010-02-22T23:59:59.000Z

253

Effects of eddy currents due to a vacuum chamber wall in the airgap of a moving-magnet linear actuator  

SciTech Connect (OSTI)

This paper discusses the effects of eddy currents induced in an electrically conducting plate which is placed in the airgap of a linear synchronous actuator with moving permanent magnets. The eddy currents induced in this plate, which is part of a controlled atmosphere chamber, cause not only damping but also deteriorate the actuator performance by disturbing the position measurement with Hall sensors. Furthermore, feed-forward controllers are less effective due to the suppression of high frequent armature fields. These effects are analyzed with an analytical model and verified with finite element simulations and measurements.

Jansen, J. W.; Lomonova, E. A.; Rovers, J. M. M. [Department of Electrical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven (Netherlands)

2009-04-01T23:59:59.000Z

254

Dynamics of positive probes in underdense, strongly magnetized, EB drifting plasma: Particle-in-cell simulations  

SciTech Connect (OSTI)

Electron trapping, electron heating, space-charge wings, wake eddies, and current collection by a positive probe in EB drifting plasma were studied in three-dimensional electromagnetic particle-in-cell simulations. In these simulations, electrons and ions were magnetized with respect to the probe and the plasma was underdense (?{sub pe}large drift velocity (Mach 4.5 with respect to the ion acoustic speed) between the plasma and probe was created with background electric and magnetic fields. Four distinct regions developed in the presences of the positive probe: a quasi-trapped electron region, an electron-depletion wing, an ion-rich wing, and a wake region. We report on the observations of strong electron heating mechanisms, space-charge wings, ion cyclotron charge-density eddies in the wake, electron acceleration due to a magnetic presheath, and the current-voltage relationship.

Heinrich, Jonathon R.; Cooke, David L. [Air Force Research Laboratory, Kirtland Air Force Base, New Mexico 87117 (United States)] [Air Force Research Laboratory, Kirtland Air Force Base, New Mexico 87117 (United States)

2013-09-15T23:59:59.000Z

255

Direct measurements of the mean flow and eddy kinetic energy structure of the upper ocean circulation in the NE Atlantic  

E-Print Network [OSTI]

Direct measurements of the mean flow and eddy kinetic energy structure of the upper ocean, University of Bergen, Bergen, Norway Tom Rossby Graduate School of Oceanography, University of Rhode Island and variable wind-forcing, and strong and variable deep currents that lead to large uncertainties in the use

256

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.

257

Lattice Boltzmann simulation of solute transport in heterogeneous porous media with conduits to estimate macroscopic continuous time random walk model parameters  

SciTech Connect (OSTI)

Lattice Boltzmann models simulate solute transport in porous media traversed by conduits. Resulting solute breakthrough curves are fitted with Continuous Time Random Walk models. Porous media are simulated by damping flow inertia and, when the damping is large enough, a Darcy's Law solution instead of the Navier-Stokes solution normally provided by the lattice Boltzmann model is obtained. Anisotropic dispersion is incorporated using a direction-dependent relaxation time. Our particular interest is to simulate transport processes outside the applicability of the standard Advection-Dispersion Equation (ADE) including eddy mixing in conduits. The ADE fails to adequately fit any of these breakthrough curves.

Anwar, S.; Cortis, A.; Sukop, M.

2008-10-20T23:59:59.000Z

258

TERRITORIAL ASSEMBLAGES SIMULATION FOR TERRITORIAL INTELLIGENCE Eddie Soulier  

E-Print Network [OSTI]

information and use the technologies of information and communication through Intranet and Internet sites and multidisciplinary approach, which uses technologies of information and communication, integrates multi and technologies of information and communication (STIC) and on knowledge management. The connections

Paris-Sud XI, Université de

259

Eddy Influences on Hadley Circulations: Simulations with an Idealized GCM  

Science Journals Connector (OSTI)

An idealized GCM is used to investigate how the strength and meridional extent of the Hadley circulation depend on the planet radius, rotation rate, and thermal driving. Over wide parameter ranges, the strength and meridional extent of the Hadley ...

Christopher C. Walker; Tapio Schneider

2006-12-01T23:59:59.000Z

260

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

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

The Effective Static Stability Experienced by Eddies in a Moist Atmosphere  

E-Print Network [OSTI]

Water vapor directly affects the dynamics of atmospheric eddy circulations through the release of latent heat.

O'Gorman, Paul Ambrose

262

Eddy current characterization of metal foams  

SciTech Connect (OSTI)

Cellular materials are characterized by their relative density, pore shape and orientation, the average cell size, and the degree of pore interconnectivity which all depend upon the method and conditions used for processing. This has created an interest in non-invasive sensor techniques to characterize the foam structure. Multifrequency electrical impedance measurements were performed using an eddy current technique on open cell aluminum foam with systematically varied relative densities and pore sizes. The impedance was dominated at all frequencies by the amount of metal contained within a probed volume of foam and the tortuosity of the current path. At low frequency, the impedance data were found to be relatively insensitive to pore size variations enabling an independent measure of the relative density. At higher frequency, the data indicated a strong dependence on the cell size.

Dharmasena, K.P.; Wadley, H.N.G. [Univ. of Virginia, Charlottesville, VA (United States). Intelligent Processing of Materials Lab.

1998-12-31T23:59:59.000Z

263

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

264

Satellite Observations of Mesoscale Eddy-Induced Ekman Pumping  

Science Journals Connector (OSTI)

Three mechanisms for self-induced Ekman pumping in the interiors of mesoscale ocean eddies are investigated. The first arises from the surface stress that occurs because of differences between surface wind and ocean velocities, resulting in Ekman ...

Peter Gaube; Dudley B. Chelton; Roger M. Samelson; Michael G. Schlax; Larry W. ONeill

265

A continuous reading fluorescence meter for eddy diffusion studies  

E-Print Network [OSTI]

LIBRARY A AIS COLLEGE OF TEXAS A CONTINUOUS READINO FLUORESCENCE METER FOR EDDY DIFFUSION STUDIES BY Frank Wooten Moon, Jr. A Thesis Submitted to ths Qraduate Scbool of the Agricultural and Mechanical College oi' Texas in partial...

Moon, Frank Wooten

1956-01-01T23:59:59.000Z

266

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.

267

A Large-Scale Test of Free-Energy Simulation Estimates of ProteinLigand Binding Affinities  

Science Journals Connector (OSTI)

We have performed a large-scale test of alchemical perturbation calculations with the Bennett acceptance-ratio (BAR) approach to estimate relative affinities for the binding of 107 ligands to 10 different proteins. Employing 20- truncated spherical ...

Paulius Mikulskis; Samuel Genheden; Ulf Ryde

2014-09-29T23:59:59.000Z

268

Generation of acoustic-gravity waves in ionospheric HF heating experiments : simulating large-scale natural heat sources  

E-Print Network [OSTI]

In this thesis, we investigate the potential role played by large-scale anomalous heat sources (e.g. prolonged heat wave events) in generating acoustic-gravity waves (AGWs) that might trigger widespread plasma turbulence ...

Pradipta, Rezy

2012-01-01T23:59:59.000Z

269

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

E-Print Network [OSTI]

fault zone, and a confined area of both fresh and saline water zones. The Edwards Aquifer is also one of the most productive carbonate aquifers in the United States, with large porosity and high permeability due to limestone dissolution... fault zone, and a confined area of both fresh and saline water zones. The Edwards Aquifer is also one of the most productive carbonate aquifers in the United States, with large porosity and high permeability due to limestone dissolution...

Taucer, Philip Isaiah

2006-08-16T23:59:59.000Z

270

Stochastic variability of large-scale oceanic flows above topography anomalies Antoine Venaille,  

E-Print Network [OSTI]

, the ubiquity of red noise signals in time series of various oceanic metrics is generally thought to result from but with sufficient spatial resolution to simulate the "oceanic weather system", i.e. mesoscale eddies at scale from

271

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

272

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

Science Journals Connector (OSTI)

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

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

2011-01-01T23:59:59.000Z

273

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

274

Wind tunnel simulation of exhaust recirculation in an air-cooling system at a large power plant  

Science Journals Connector (OSTI)

The recirculation of hot exhaust air and its dependence on wind direction was investigated as a cause of reduced efficiency in an air-cooled condenser (ACC). A method of simulating exhaust air recirculation at an ACC platform using a wind tunnel is presented, and applied to a proposed ACC addition at an existing power plant. It was found that wind speed and the height of an ACC platform have a significant impact on recirculation. Wind direction was also found to be significant, due to the interference of the buildings adjacent to the ACC platform. The mechanisms that cause recirculation are presented and analyzed, and the characteristics of the recirculating flow are described. It was found that when considering additions to existing power plants, the distance of the new ACC and power plant from the original buildings and structures has only a minor effect on the recirculation of the added ACC platform. Wind tunnel simulation is recommended in the initial design stage of new or renovated power plants with ACC systems to minimize exhaust recirculation.

Zhifu Gu; Xuerei Chen; William Lubitz; Yan Li; Wenlin Luo

2007-01-01T23:59:59.000Z

275

Is it Cost-Effective to Replace Old Eddy-Current Drives? | Department...  

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

Is it Cost-Effective to Replace Old Eddy-Current Drives? Is it Cost-Effective to Replace Old Eddy-Current Drives? New pulse-width-modulated (PWM) adjustable speed drives (ASDs) may...

276

Mixed Layer Lateral Eddy Fluxes Mediated by Air-Sea Interaction  

E-Print Network [OSTI]

The modulation of airsea 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 airsea ...

Shuckburgh, Emily

277

Seasonal Mesoscale and Submesoscale Eddy Variability along the North Pacific Subtropical Countercurrent  

Science Journals Connector (OSTI)

Located at the center of the western North Pacific Subtropical Gyre, the Subtropical Countercurrent (STCC) is not only abundant in mesoscale eddies, but also exhibits prominent submesoscale eddy features. Output from a high-resolution OGCM ...

Bo Qiu; Shuiming Chen; Patrice Klein; Hideharu Sasaki; Yoshikazu Sasai

2014-12-01T23:59:59.000Z

278

Equatorial Pacific 13C Water Eddies in the Eastern Subtropical South Pacific Ocean  

Science Journals Connector (OSTI)

Argo float profile data are used to analyze warm, salty, weakly stratified, subthermocline eddies of tropical origin in the eastern subtropical South Pacific Ocean. These eddies contain anomalous signatures of the equatorial Pacific 13C Water ...

Gregory C. Johnson; Kristene E. McTaggart

2010-01-01T23:59:59.000Z

279

On the ratio between shifts in the eddy-driven jet and the Hadley cell edge  

Science Journals Connector (OSTI)

This study explores the relationship between latitudinal shifts in the eddy-driven jet and in the Hadley cell edge as depicted in models and ... 1 between the eddy-driven jet and the Hadley cell edge over the Sou...

Paul W. Staten; Thomas Reichler

2014-03-01T23:59:59.000Z

280

New Eddy Correlation System for ARM SGP Site  

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

New Eddy Correlation System for ARM SGP Site New Eddy Correlation System for ARM SGP Site M. S. Pekour Argonne National Laboratory Argonne, Illinois Background Eddy correlation (ECOR) systems are widely used for in situ measurement of the turbulent fluxes in the atmosphere. The ECOR technique is the most direct method for determining fluxes; vertical fluxes are obtained by correlating the vertical wind component with the horizontal wind component (momentum flux), temperature (sensible heat flux), water vapor density (latent heat flux), and a scalar admixture density (e.g., CO 2 flux). Typically, an ultrasonic anemometer-thermometer ("sonic anemometer") is used for rapid, high-precision, three-dimensional (3D) wind measurements, as well as for temperature fluctuation measurements. A fast-response humidity sensor, such as an infra-red gas analyzer (IRGA) is

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

Microsoft Word - Eddy-LeaCommission20030618.doc  

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

June 18, 2003 June 18, 2003 Department of Energy Awards Eddy/Lea Regional Commission $300,000 Grant WASHINGTON, DC - Secretary of Energy Spencer Abraham announced today that the Department of Energy will award $300,000 to the Eddy/Lea Regional Commission, the community reuse organization (CRO) for southern New Mexico. This grant will fund part of the commission's operating costs, as well as other specific projects, including continuing the business expansion and retention of a 28-block downtown area and assisting in efforts to create new jobs by recruiting new business and industry. "The Energy Department is a good neighbor to the communities surrounding our sites," Secretary Abraham said. "We will continue to work with the Eddy/Lea Regional Commission and

282

Simulated and measured data-line parasitic capacitance of amorphous silicon large-area image sensor arrays  

Science Journals Connector (OSTI)

Calculations and measurements of parasitic capacitance in active matrix sensor arrays used for light and x-ray imaging are presented. We focus on arrays with continuous sensor layers and base the calculations on actual structures used for x-ray and light imaging. Different cross sections of the pixel allow the various components of the capacitance from the thin film transistor the sensor and metal crossovers to be determined by numerical two-dimensional solution of Poissons equation. The calculations give the total and the individual components of the parasitic capacitance in the data line and allow us to evaluate their effect on electronic noise and imager sensitivity. The theoretical values are compared to measurements performed on arrays with 75 ?m pixel pitch showing agreement within 10%20%. The numerical simulations are used to determine the optimized array configuration that can reduce the parasitic capacitance to ?6 fF/pixel which is only 15% of the present values. The capacitance is compared for direct and indirect x-ray detectionimagers using PbI 2 and a- Si:H sensor layers respectively.

M. Mulato; J. P. Lu; R. A. Street

2001-01-01T23:59:59.000Z

283

A Novel and Scalable Spatio-Temporal Technique for Ocean Eddy Monitoring James H. Faghmous  

E-Print Network [OSTI]

Swirls of ocean currents known as ocean eddies are a crucial component of the ocean's dynamics, understanding past and current eddy activity is crucial for forecasting future ocean dynamics and, subseA Novel and Scalable Spatio-Temporal Technique for Ocean Eddy Monitoring James H. Faghmous , Yashu

Minnesota, University of

284

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.

285

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

286

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

287

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

288

The influence of mesoscale eddies on shallow water acoustic propagation  

Science Journals Connector (OSTI)

Acoustic propagation measurements in 150 m depth on the Florida escarpment observe the effects of the passage of a cyclonic eddy. As the stream core of the Florida Current meanders the eddy is formed and propagates along the shelf edge. The sequence over a roughly a fortnight is as follows: ahead of the eddy warm surface water and cold bottom water are swept onto the terrace forming a steep thermocline and corresponding strong downward refracting C(z). The gradient produce intense focused RBR arrivals and the thermocline becomes a duct for internal waves to propagate shoreward. At first the internal wave energy is minimal and propagation is stable and coherent. As the internal tides attempt to propagate on shelf the sound speed field and the acoustic signals become increasingly variable. The variability reaches a crescendo as the 200 m long internal tide is blocked from propagating on to the narrower shelf and begins to break and overturn producing small?scale variability. As the eddy passes nearly iso?thermal conditions are restored along with quiescent internal wave fields and reduced signal variability. Here the effects are quantized with data from fixed?system acoustic and oceanographic measurements demonstrating that the mesoscale determines acoustic propagation conditions days in advance.

2003-01-01T23:59:59.000Z

289

On the Use of Integrated Daylighting and Energy Simulations To Drive the Design of a Large Net-Zero Energy Office Building: Preprint  

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

522 522 August 2010 On the Use of Integrated Daylighting and Energy Simulations To Drive the Design of a Large Net-Zero Energy Office Building Preprint Rob Guglielmetti, Shanti Pless, and Paul Torcellini Presented at SimBuild 2010 New York, New York August 15-19, 2010 NOTICE The submitted manuscript has been offered by an employee of the Alliance for Sustainable Energy, LLC (Alliance), a contractor of the US Government under Contract No. DE-AC36-08GO28308. Accordingly, the US Government and Alliance retain a nonexclusive royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for US Government purposes. This report was prepared as an account of work sponsored by an agency of the United States government.

290

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"

291

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

292

Eddy County, New Mexico: Energy Resources | Open Energy Information  

Open Energy Info (EERE)

Eddy County, New Mexico: Energy Resources Eddy County, New Mexico: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 32.4170622°, -104.4723301° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":32.4170622,"lon":-104.4723301,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

293

Microsoft Word - CX-BigEddy-Ostrander_WEB.doc  

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

4 4 SUBJECT: Environmental Clearance Memorandum Elizabeth Johnson - TFR-The Dalles Natural Resource Specialist Proposed Action: Perform routine access road maintenance within the Big Eddy-Ostrander No. 1 transmission line corridor Budget Information: Work Order # 00261716 PP&A Project No.: PP&A 1706 Categorical Exclusion Applied (from Subpart D, 10 C.F.R. Part 1021): B1.3, Routine maintenance activities...for structures, rights-of-way, infrastructures such as roads, equipment... routine maintenance activities, corrective....are required to maintain... infrastructures...in a condition suitable for a facility to be used for its designed purpose. Proposed by: Bonneville Power Administration (BPA) Location: The project area is located along BPA's Big Eddy-Ostrander No. 1 transmission line

294

A stabilized proper orthogonal decomposition reduced-order model for large scale quasigeostrophic ocean circulation  

E-Print Network [OSTI]

In this paper, a stabilized proper orthogonal decomposition (POD) reduced-order model (ROM) is presented for the barotropic vorticity equation. We apply the POD-ROM model to mid-latitude simplified oceanic basins, which are standard prototypes of more realistic large-scale ocean dynamics. A mode dependent eddy viscosity closure scheme is used to model the effects of the discarded POD modes. A sensitivity analysis with respect to the free eddy viscosity stabilization parameter is performed for various POD-ROMs with different numbers of POD modes. The POD-ROM results are validated against the Munk layer resolving direct numerical simulations using a fully conservative fourth-order Arakawa scheme. A comparison with the standard Galerkin POD-ROM without any stabilization is also included in our investigation. Significant improvements in the accuracy over the standard Galerkin model are shown for a four-gyre ocean circulation problem. This first step in the numerical assessment of the POD-ROM shows that it could r...

San, Omer

2014-01-01T23:59:59.000Z

295

RECENT IMPROVEMENTS IN HIGH?FREQUENCY EDDY CURRENT CONDUCTIVITY SPECTROSCOPY  

Science Journals Connector (OSTI)

Due to its frequency?dependent penetration depth eddy current measurements are capable of mapping near?surface residual stress profiles based on the so?called piezoresistivity effect i.e. the stress?dependence of electric conductivity. To capture the peak compressive residual stress in moderately shot?peened (Almen 48A) nickel?base superalloys the eddy current inspection frequency has to go as high as 5080 MHz. Recently we have reported the development of a new high?frequency eddy current conductivity measuring system that offers an extended inspection frequency range up to 80 MHz. Unfortunately spurious self? and stray?capacitance effects render the complex coil impedance variation with lift?off more nonlinear as the frequency increases which makes it difficult to achieve accurate apparent eddy current conductivity (AECC) measurements with the standard four?point linear interpolation method beyond 25 MHz. In this paper we will demonstrate that reducing the coil size reduces its sensitivity to capacitive lift?off variations which is just the opposite of the better known inductive lift?off effect. Although reducing the coil size also reduces its absolute electric impedance and relative sensitivity to conductivity variations a smaller coil still yields better overall performance for residual stress assessment. In addition we will demonstrate the benefits of a semi?quadratic interpolation scheme that together with the reduced lift?off sensitivity of the smaller probe coil minimizes and in some cases completely eliminates the sensitivity of AECC measurements to lift?off uncertainties. These modifications allow us to do much more robust measurements up to as high as 80100 MHz with the required high relative accuracy of +/?0.1%.

Bassam A. Abu?Nabah; Peter B. Nagy

2008-01-01T23:59:59.000Z

296

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

297

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

298

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

299

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

300

Influence of mesoscale eddies on sound propagation in the northwest Pacific Ocean  

Science Journals Connector (OSTI)

The influence of a warm anticyclonic eddy occurring in the northwestern part of the Pacific Ocean near the Kuroshio flow on the sound...

V. A. Akulichev; L. K. Bugaeva; Yu. N. Morgunov; A. A. Solovev

2011-12-01T23:59:59.000Z

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.


301

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

302

Assessing thermal barrier coatings by eddy-current inversion  

Science Journals Connector (OSTI)

The nondestructive evaluation (NDE) of high-temperature coatings is one of the important factors in achieving a high level of structural integrity in advanced gas turbines. In this paper we demonstrate that sophisticated eddy-current techniques can be utilized to measure the thickness and remaining-life of high-temperature coatings. We discuss the difficult in-service case in which the time-temperature exposure of the combustion turbine blade has created a four-layered system in addition to the base metal.

Harold A. Sabbagh; Elias H. Sabbagh; R. Kim Murphy; John Nyenhuis

2002-01-01T23:59:59.000Z

303

Deep Eddy Energy and Topographic Rossby Waves in the Gulf of Mexico  

Science Journals Connector (OSTI)

Observations suggest the hypothesis that deep eddy kinetic energy (EKE) in the Gulf of Mexico can be accounted for by topographic Rossby waves (TRWs). It is presumed that the TRWs are forced by Loop Current (LC) pulsation, Loop Current eddy (LCE) ...

L-Y. Oey; H-C. Lee

2002-12-01T23:59:59.000Z

304

Extremely short impulse eddy current system for titanium and inconel samples testing  

SciTech Connect (OSTI)

This paper presents a new system for eddy current testing. The system enables tests with very short current impulses. Therefore, the frequency spectrum of the excitation signal is very wide. In this paper, a study of eddy current differential transducer for testing titanium element is also presented.

Chady, T.; Frankowski, P. [Faculty of Electrical Engineering, West Pomeranian University of Technology, Sikorskiego 37, 70-313 Szczecin (Poland)

2011-06-23T23:59:59.000Z

305

MEAN AND EDDY DYNAMICS OF THE MAIN THERMOCLINE GEOFFREY K. VALLIS  

E-Print Network [OSTI]

show a tendency to develop into a `two-fluid' state -- a pool of warm subtropical near surface water, the upper thermocline (below the surface mixed layer) is conservative and advectively dominated -- that is mesoscale eddies. The eddies are strongest in regions of western boundary currents, `mode water' regions

Vallis, Geoff

306

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

E-Print Network [OSTI]

of eddy energy. 1. Introduction Continental boundaries lead to a mean oceanic strati- fication with both vorticity gradient. In practical terms, this means that the oceanic available potential energy stored in east­west gradients of the pycnocline is more easily converted to eddy kinetic energy than that stored

Smith, K. Shafer

307

Eddy-driven Responses of the Hadley Cell and Jacob Haqq-Misra  

E-Print Network [OSTI]

Eddy-driven Responses of the Hadley Cell and Tropopause Jacob Haqq-Misra Department of Meteorology of eddies on the Hadley circulation and tropopause structure using an3 idealized three-dimensional general fluxes on the general circulation is necessary to reproduce an Earth-9 like Hadley cell. Additionally

Frierson, Dargan

308

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

309

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

310

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

E-Print Network [OSTI]

behind Gran Canaria [Sangra et al., 2007]. The relative importance of the wind and current in eddy that a sufficiently strong incident current ($0.2­0.7 m s?1 ) can induce eddy sepa- ration behind Gran Canaria

311

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

312

EIS-0421: Big Eddy-Knight Transmission Line | Department of Energy  

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

21: Big Eddy-Knight Transmission Line 21: Big Eddy-Knight Transmission Line EIS-0421: Big Eddy-Knight Transmission Line Overview BPA is proposing to build a new 500 kilovolt (kV) transmission line in Wasco County, Oregon and Klickitat County, Washington and a new substation in Klickitat County. The new BPA transmission line would extend generally northeast from BPA's existing Big Eddy Substation in The Dalles, Oregon, to a new substation (Knight Substation) proposed to be connected to an existing BPA line about 4 miles northwest of Goldendale, Washington. The proposed Big Eddy Knight Transmission Project is needed to increase transmission capacity to respond to requests for transmission service in this area. Public Comment Opportunities No public comment opportunities available at this time.

313

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.

314

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

315

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

316

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

317

Design and Research on Co-simulation Training System of Large-Scale Power Grid with Distribution Network Based on Intelligent Materials System  

Science Journals Connector (OSTI)

The power system training simulation software, exist in the market, ... flow calculation without the local details or equipment operation, or focus on one or two substations, but ignoring the power of the substat...

BaiShan Mei; XiPing Zhang; Jie Xu

2011-01-01T23:59:59.000Z

318

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

319

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

320

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

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

Eddy?Current Inspection of Cracking in Land?Based Gas Turbine Blades  

Science Journals Connector (OSTI)

There has been a growing need in the electric utility industry to assess the remaining life of blades in gas turbines. It is quite important to nondestructively comprehend the depths of surface?breaking cracks in blades. Flexible eddy current array probes have been developed to overcome the major limitations of existing eddy current inspection systems. The use of an array of sensors allows cracks of all lengths to be detected and will ultimately allow real time data imaging to provide rapid inspection and easy interpretation. For this study using eddy current techniques crack detection equipment has been developed and applied to gas turbine Stage 1 blades for field use.

H. Fukutomi; T. Ogata

2004-01-01T23:59:59.000Z

322

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

323

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

324

Six-Week Time Series Of Eddy Covariance Co2 Flux At Mammoth Mountain,  

Open Energy Info (EERE)

Six-Week Time Series Of Eddy Covariance Co2 Flux At Mammoth Mountain, Six-Week Time Series Of Eddy Covariance Co2 Flux At Mammoth Mountain, California- Performance Evaluation And Role Of Meteorological Forcing Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Six-Week Time Series Of Eddy Covariance Co2 Flux At Mammoth Mountain, California- Performance Evaluation And Role Of Meteorological Forcing Details Activities (1) Areas (1) Regions (0) Abstract: CO2 and heat fluxes were measured over a six-week period (09/08/2006 to 10/24/2006) by the eddy covariance (EC) technique at the Horseshoe Lake tree kill (HLTK), Mammoth Mountain, CA, a site with complex terrain and high, spatially heterogeneous CO2 emission rates. EC CO2 fluxes ranged from 218 to 3500 g m- 2 d- 1 (mean = 1346 g m- 2 d- 1). Using footprint modeling, EC CO2 fluxes were compared to CO2 fluxes measured by

325

Multidecadal variability of the overturning circulation in presence of eddy turbulence.  

Science Journals Connector (OSTI)

At low resolution, idealized ocean circulation models forced by prescribed differential surface heat fluxes show spontaneous multidecadal variability depending critically on eddy diffusivity coefficients. The existence of this critical threshold ...

Thierry Huck; Olivier Arzel; Florian Svellec

326

Role of Resolved and Parameterized Eddies in the Labrador Sea Balance of Heat and Buoyancy  

Science Journals Connector (OSTI)

Deep convection in the Labrador Sea is an important component of the global ocean ventilation. The associated loss of heat to the atmosphere from the interior of the sea is thought to be mostly supplied by mesoscale eddies, generated either ...

Oleg A. Saenko; Frdric Dupont; Duo Yang; Paul G. Myers; Igor Yashayaev; Gregory C. Smith

2014-12-01T23:59:59.000Z

327

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

328

Spatial and temporal variability of major ocean currents and mesoscale eddies  

Science Journals Connector (OSTI)

A global picture of ocean current variability may be obtained by analyzing surface drift currents in terms of their mean and eddy ... both quantities are found in the western boundary currents and in the equatori...

Walter Ding

1978-01-01T23:59:59.000Z

329

Meso-scale eddies affect near-surface turbulent exchange: evidence from lidar and tower measurements  

Science Journals Connector (OSTI)

The eddy-covariance technique tends to underestimate the turbulent heat fluxes, which results in the non-closure of the surface energy balance. This study shows experimental evidence that meso-scale turbulent organized structures, which are ...

Fabian Eder; Marius Schmidt; Thomas Damian; Katja Trumner; Matthias Mauder

330

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

331

Implementation of a Stochastic Eddy-Diffusivity/Mass-Flux Parameterization into the Navy Global Environmental Model  

Science Journals Connector (OSTI)

A unified boundary layer and shallow convection parameterization based on a stochastic eddy-diffusivity/mass-flux (EDMF) approach is implemented and tested in the Navy Global Environmental Model (NAVGEM). The primary goals of this work are to ...

Kay Suelj; Timothy F. Hogan; Joo Teixeira

2014-12-01T23:59:59.000Z

332

A Modeling Study of Circulation and Eddies in the Persian Gulf  

Science Journals Connector (OSTI)

The circulation and mesoscale eddies in the Persian Gulf are investigated using results from a high-resolution (?1 km) Hybrid Coordinate Ocean Model (HYCOM). The circulation in the Persian Gulf is composed of two spatial scales: basin scale and ...

Prasad G. Thoppil; Patrick J. Hogan

2010-09-01T23:59:59.000Z

333

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

334

Efficient Geomechanical Simulations of Large-Scale Naturally Fractured Reservoirs Using the Fast Multipole-Displacement Discontinuity Method (FM-DDM)  

E-Print Network [OSTI]

....................................................................... 63 5.2.2. FED model evaluation Cases 5 and 6 .......................................................... 66 5.2.3. FPDD model evaluation Case 7 .................................................................. 73 6. NUMERICAL APPLICATIONS... to injection Case 3. ......... 89 6.4. Fluid injection and production in large-scale poroelastic shales Case 4. ........... 92 7. CONCLUSIONS AND RECOMMENDATIONS ....................................................... 99 7.1. Conclusions...

Verde Salas, Alexander Jos

2014-04-28T23:59:59.000Z

335

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

336

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

337

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

338

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.

339

Parameterization of mixed layer eddies. III: Implementation and impact in global ocean climate simulations  

E-Print Network [OSTI]

., 2007; Price et al., 2008). A front stores poten- tial energy in the horizontal juxtaposition of dense, Massachusetts Institute of Technology, Cambridge, MA, USA e NOAA Geophysical Fluid Dynamics Laboratory n f o Article history: Available online 17 September 2010 Keywords: Submesoscale Parameterization

Ferrari, Raffaele

340

Parameterization of mixed layer eddies. III: Implementation and impact in global ocean climate simulations  

E-Print Network [OSTI]

., 2007; Price et al., 2008). A front stores poten- tial energy in the horizontal juxtaposition of dense, Massachusetts Institute of Technology, Cambridge, MA, USA e NOAA Geophysical Fluid Dynamics Laboratory n f o Article history: Available online xxxx Keywords: Submesoscale Parameterization Mixed layer

Ferrari, Raffaele

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

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 is a cost-shared field demonstration project in the US Department of Energy Class II Program. A major goal of the Class III Program is to stimulate the use of advanced technologies to increase ultimate recovery from slope-basin clastic reservoirs. Advanced characterization techniques are being used at the Nash Draw project to develop reservoir management strategies for optimizing oil recovery from this Delaware reservoir. Analysis, interpretation, and integration of recently acquired geologic, 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 is being 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 simulation, and well spacing to improve recovery from this reservoir.

Murphy, Mark B.

1999-02-24T23:59:59.000Z

342

Microsoft Word - CX-Big Eddy-TroutdaleUpgradeFY12_WEB.doc  

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

Erich Orth Erich Orth Project Manager - TEP-TPP-3 Proposed Action: Big Eddy - Troutdale No. 1 230 kV Transmission Line Upgrade Categorical Exclusion Applied (from Subpart D, 10 C.F.R. Part 1021): Appendix B4.13, Upgrading and Rebuilding Existing Powerlines. Location: Wasco, Hood River and Clackamas counties, OR Proposed by: Bonneville Power Administration (BPA) Description of the Proposed Action: The project, as proposed, is the thermal upgrade of the BPA Big Eddy - Troutdale No.1 230 kV Transmission Line: Background BPA's Big Eddy - Troutdale No. 1 230-kV transmission line is one of three major transmission lines that cross the Oregon Cascade Mountains. These lines transport The Dalles hydro generation and northwest wind generation output in the east to load centers west of the Cascades, like

343

Computer programs for the acquisition and analysis of eddy-current array probe data  

SciTech Connect (OSTI)

Objective of the Improved Eddy-Curent ISI (in-service inspection) for Steam Generators Tubing program is to upgrade and validate eddy-current inspections, including probes, instrumentation, and data processing techniques for ISI of new, used, and repaired steam generator tubes; to improve defect detection, classification and characterization as affected by diameter and thickness variations, denting, probe wobble, tube sheet, tube supports, copper and sludge deposits, even when defect types and other variables occur in combination; to transfer this advanced technology to NRC`s mobile NDE laboratory and staff. This report documents computer programs that were developed for acquisition of eddy-current data from specially designed 16-coil array probes. Complete code as well as instructions for use are provided.

Pate, J.R.; Dodd, C.V.

1996-07-01T23:59:59.000Z

344

GEOPHYSICAL RESEARCH LETTERS, VOL. ???, XXXX, DOI:10.1029/, Role of eddies in the interannual variability of Hadley cell  

E-Print Network [OSTI]

variability of Hadley cell strength Rodrigo Caballero Meteorology and Climate Centre, School of Mathematical that extratropical eddies strongly affect the Hadley cell mass flux. Here, we use reanalysis data to assess the role of eddy mo- mentum transport in the interannual variability of northern hemisphere winter Hadley cell

Caballero, Rodrigo

345

On the ratio between shifts in the eddy-driven jet and the Hadley Paul W. Staten Thomas Reichler  

E-Print Network [OSTI]

On the ratio between shifts in the eddy-driven jet and the Hadley cell edge Paul W. Staten · Thomas and in the Hadley cell edge as depicted in models and reanalyses. We cal- culate an interannual shift ratio of approximately 1.5:1 between the eddy-driven jet and the Hadley cell edge over the Southern Hemisphere during

Reichler, Thomas

346

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.

347

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

348

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

349

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

350

High-fidelity simulations of unsteady civil aircraft aerodynamics: stakes and perspectives. Application of zonal detached eddy simulation  

Science Journals Connector (OSTI)

...pacing item in aerospace engineering and...Deck, S . 2012 Recent improvements of...In 50th AIAA Aerospace Sciences Meeting. AIAA...configuration. In Advances in Hybrid RANS-LES...Methods in Applied Sciences and Engineering...

2014-01-01T23:59:59.000Z

351

High-fidelity simulations of unsteady civil aircraft aerodynamics: stakes and perspectives. Application of zonal detached eddy simulation  

Science Journals Connector (OSTI)

...achieved and therefore less gas emissions are produced by the...Flightpath 2050, Europe's vision for aviation. Technical report...and D Mavriplis. 2013 CFD vision 2030 study: a path to revolutionary...and X Yang. 2014 LES for turbines: methodologies, cost and future...

2014-01-01T23:59:59.000Z

352

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

353

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

354

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

355

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

356

Using a High-Frequency Fluorescent Oxygen Probe in Atmospheric Eddy Covariance Applications  

Science Journals Connector (OSTI)

During the years 201013, atmospheric eddy covariance measurement of oxygen was performed at the marine site stergarnsholm in the Baltic Sea. The fast response optode Microx TX3 was used with two different types of tapered sensors. In spite of ...

Andreas Andersson; Anna Rutgersson; Erik Sahle

2014-11-01T23:59:59.000Z

357

Evaluation of outer flaws in titanium alloys using eddy current measuring system  

SciTech Connect (OSTI)

In this paper results of shallow outer flaw detection in thick titanium alloy specimens is presented. In order to increase efficiency of inspections of minor defects an eddy current measuring system with a lock-in amplifier was used. The measurements were carried out for flat and cylindrical specimens with artificial flaws.

Chady, T.; Psuj, G.; Kowalczyk, J. [Department of Electrical and Computer Engineering, West Pomeranian University of Technology in Szczecin, ul. Sikorskiego 37, 70-313 Szczecin (Poland)

2011-06-23T23:59:59.000Z

358

Exploring the eddy current excitation invariance to infer about defect characteristics  

SciTech Connect (OSTI)

This paper explores the excitation probe excitation field invariance when the eddy current method is applied to detect, localize and characterize material defects in conductive nonmagnetic media. The cases relative to rotational symmetry in circular solenoidal probes and translation symmetry in constant field probes are presented. The experimental data shows that this theoretical treatment is useful to preview the behavior of these probes.

Ribeiro, A. Lopes; Ramos, H. G. [I and M Group, Instituto de Telecomunicacoes, Lisboa, Portugal Instituto Superior Tecnico, DEEC, Lisboa (Portugal)

2011-06-23T23:59:59.000Z

359

The Role of Eddies in the Southern Ocean Temperature Response to the Southern Annular Mode  

E-Print Network [OSTI]

of the model show an increase in eddy kinetic energy that peaks 2­3 yr after a positive anomaly in the SAM this temperature response. This response is also evident in the coarse-resolution implementation of the model to cold SST anomalies at these latitudes. Further north, between 258 and 458S, easterly wind anomalies

Stevens, David

360

An Unusual Aerial Photograph of an Eddy Circulation in Marine Stratocumulus Clouds  

Science Journals Connector (OSTI)

An aerial photograph of a cyclonic, von Karman-like vortex in the marine stratocumulus clouds off the California coast, taken by a commercial pilot near Grover Beach, is presented. It is believed that this is the first photograph of such an eddy, ...

Bradley M. Muller; Christopher G. Herbster; Frederick R. Mosher

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

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

362

Eddy kinetic energy and small-scale sea level height variability  

E-Print Network [OSTI]

the two are obtained for the long- and short-wave (compared to the grid scale) portions of the ocean power is established between the ocean near-surface geostrophic ki- netic energy and the small-scale variance of its an important dynamical attribute of the ocean, is often used to describe its mesoscale variability, or eddy

363

The relationship between the ITCZ and the Southern Hemispheric eddy-driven jet  

E-Print Network [OSTI]

in the asymmetry of the Hadley cells: as the ITCZ shifts away from the Equator, the cross-equatorial Hadley cell of the Hadley cells. [3] While it is well established that the eddy-driven midlat- itude jet and the tropical Hadley circulation can mutually influence each other, the mechanisms and the causal relations behind

Hartmann, Dennis

364

Propagation of Wind Energy into the Deep Ocean through a Fully Turbulent Mesoscale Eddy Field  

Science Journals Connector (OSTI)

The authors analyze the 3D propagation of wind-forced near-inertial motions in a fully turbulent mesoscale eddy field with a primitive equation numerical model. Although the wind stress is uniform, the near-inertial motion field quickly becomes ...

Eric Danioux; Patrice Klein; Pascal Rivire

2008-10-01T23:59:59.000Z

365

Radiative Impacts on the Growth of a Population of Drops within Simulated Summertime Arctic Stratus  

Science Journals Connector (OSTI)

The impact of solar heating and infrared cooling on the growth of a population of drops is studied with two numerical modeling frameworks. An eddy-resolving model (ERM) simulation of Arctic stratus clouds is used to generate a dataset of 500 ...

Jerry Y. Harrington; Graham Feingold; William R. Cotton

2000-03-01T23:59:59.000Z

366

Nearby boundaries create eddies near microscopic filter feeders  

Science Journals Connector (OSTI)

...28 microm apart, with the Vorticella midway between the two slides and without the...and simulations, with the Vorticella midway between two slides and with h = 127 28...coverslip (grey box), which is inserted midway between two slides, a distance h apart...

2010-01-01T23:59:59.000Z

367

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

368

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

369

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

370

Large-scale adaptive mantle convection simulation  

Science Journals Connector (OSTI)

......International Conference for High Performance Computing, Networking, Storage...International Conference for High Performance Computing, Networking, Storage...International Conference for High Performance Computing, Networking, Storage......

Carsten Burstedde; Georg Stadler; Laura Alisic; Lucas C. Wilcox; Eh Tan; Michael Gurnis; Omar Ghattas

2013-01-01T23:59:59.000Z

371

Supplement Analysis for the Transmission System Vegetation Management Program FEIS (DOE/EIS-0285/SA-147 (Big Eddy-Chenoweth NO. 1&2, Big Eddy - Midway & Chenoweth-Goldendale)  

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

1, 2003 1, 2003 REPLY TO ATTN OF: KEP-4 SUBJECT: Supplement Analysis for the Transmission System Vegetation Management Program FEIS (DOE/EIS-0285/SA-147 (Big Eddy-Chenoweth NO. 1 &2, Big Eddy - Midway & Chenoweth- Goldendale) Elizabeth Johnson Natural Resource Specialist - TFR/The Dalles Proposed Action: Vegetation Management for the Big Eddy-Chenoweth NO. 1 &2 Substation to Substation, Big Eddy - Midway Substation to 2/3) & Chenoweth-Goldendale (Substation to 2/3). Location: Project location is within Wasco County, Oregon & Klickitat County, Washington and is within the Redmond Region. Proposed by: Bonneville Power Administration (BPA). Description of the Proposal: BPA proposes to clear targeted vegetation within the right-of-way.

372

Microsoft Word - FEIS-0421-SA-01-Big Eddy-KnightDesignAdjustmentFY12_WEB.doc  

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

KEP-4 KEP-4 SUBJECT: Supplement Analysis for the Big Eddy-Knight Transmission Project Final EIS (DOE/EIS-0421/SA-1) Emmanuel Jaramillo Project Manager - TEP-TPP-1 Proposed Action: Big Eddy-Knight Transmission Project design adjustments Proposed by: Bonneville Power Administration (BPA) Location: Wasco County, Oregon and Klickitat County, Washington Background: In 2011, BPA completed the Big Eddy-Knight Transmission Project Final Environmental Impact Statement (EIS) (DOE/EIS-0421) and issued a Record of Decision (ROD) documenting its decision to build and operate the Big Eddy-Knight transmission line. Construction of the transmission line began in fall 2011 and is currently underway. Through construction and further detailed design work, project adjustments have been identified. The

373

Eddy-current testing of the hardness, wear resistance, and thickness of coatings prepared by gas-powder laser cladding  

Science Journals Connector (OSTI)

The possibility of applying the eddy-current method to estimate the composition, hardness, abrasive wear-resistance, and wear resistance under sliding friction conditions of chromium-nickel and chromium-nickel-co...

A. V. Makarov; E. S. Gorkunov; I. Yu. Malygina

2009-11-01T23:59:59.000Z

374

An Eddy Parameterization Based on Maximum Entropy Production with Application to Modeling of the Arctic Ocean Circulation  

Science Journals Connector (OSTI)

An eddy parameterization derived from statistical mechanics of potential vorticity is applied for inviscid shallow-water equations. The solution of a variational problem based on the maximum entropy production (MEP) principle provides, with some ...

Igor Polyakov

2001-08-01T23:59:59.000Z

375

TRU Solutions Announces $20,500 in Scholarships For Eddy and Lea County Students  

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

Sherry Reese Sherry Reese Public Outreach (505) 234-7592 http://www.wipp.ws Waste Isolation Pilot Plant P.O. Box 2078 Carlsbad, New Mexico 88221 TRU Solutions News For Immediate Release TRU Solutions Announces $20,500 in Scholarships For Eddy and Lea County Students CARLSBAD, N.M., February 18, 2003 - Steve Warren, Washington TRU Solutions (WTS) General Manager, has announced up to $20,500 in scholarships for Eddy and Lea County students in 2003. Applications are available now from area high school and college counselors. WTS, formerly Westinghouse TRU Solutions, will award the scholarships this spring in conjunction with area high schools, the Carlsbad Foundation and several non-profit organizations. Scholarships are available in any of the following three areas of study at an accredited

376

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

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

4, 2013 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 Replacement Project PP&A Project No.: 2500 Categorical Exclusion Applied (from Subpart D, 10 C.F.R. Part 1021): B1.3 Routine maintenance Location: Big Eddy-Redmond No. 1 transmission line in Deschutes County, Oregon, at the following locations: Mile Structure Township Range Section 35 6 5 14 24 36 6 5 14 25 36 7 5 14 25 36 8 5 14 25 37 6 5 14 36 40 9 6 15 18 43 2 6 15 29 48 4 7 1 21 49 1 7 1 21 50 6 7 15 33 51 8 8 15 5 52 8 8 15 8 53 3 8 15 8 54 2 8 15 17 56 1 8 1 30 58 2 9 14 1

377

Microsoft Word - John_Day-Big_Eddy_2-CX.doc  

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

Mark Kjelland Mark Kjelland Project Manager - TEP-TPP-3 Proposed Action: John Day-Big Eddy No. 2 500-kV Transmission Line Reconductor Budget Information: Work Order 232282 Task 01 Categorical Exclusion Applied (from Subpart D, 10 C.F.R. Part 1021): B4.6 Additions or modifications to electric power transmission facilities that would not affect the environment beyond the previously developed facility area including...tower modifications, changing insulators, and replacement of poles, circuit breakers, conductors, transformers and crossarms. Location: Sherman and Wasco counties, Oregon Proposed by: Bonneville Power Administration (BPA) Description of the Proposed Action: BPA proposes to reconductor 3 approximately 1-mile long sections of the John Day-Big Eddy No. 2 500-kV transmission line. The project involves removing the

378

Microsoft Word - CX-BigEddy-Redmond-ConductorMaintenance-FY13_WEB  

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

4, 2013 4, 2013 REPLY TO ATTN OF: KEP-4 SUBJECT: Environmental Clearance Memorandum Stacy Hensley Project Manager - TEP-CSB-2 Proposed Action: Conductor maintenance on Bonneville Power Administration's (BPA) Big Eddy-Redmond transmission line Categorical Exclusion Applied (from Subpart D, 10 C.F.R. Part 1021): B1.3 Routine maintenance activities Location: Approximately six miles southeast of The Dalles in Wasco County, Oregon. T1N, R14E, Sec 4, 5, 9, 20, 28, 29, and 33 Proposed by: BPA Description of the Proposed Action: BPA proposes to perform routine maintenance on the Big Eddy-Redmond, 230-kilovolt transmission line conductor. The proposed work includes re-sagging the transmission line, and replacing the transmission line hardware and transmission

379

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

380

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

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

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

382

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

383

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

384

Supplement Analysis for the Transmission System Vegetation Management Program FEIS (DOE/EIS-0285/SA-151-Big Eddy-Ostrander 1  

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

8, 2003 8, 2003 REPLY TO ATTN OF: KEP-4 SUBJECT: Supplement Analysis for the Transmission System Vegetation Management Program FEIS (DOE/EIS-0285/SA-151-Big Eddy-Ostrander 1 Ed Tompkins Natural Resource Specialist-TFO/LMT Proposed Action: Removal of danger trees along the Big Eddy-Ostrander-1 transmission line corridor. This corridor also includes segments of the Big Eddy-Troutdale, Ostrander-Troutdale, Big Eddy-McLoughlin and Bid Eddy-Chemawa transmission lines. Referencing the Big-Eddy- Ostrander-1 transmission line, the project extends from tower 39/3 to 72/2. The portion of the ROW extending from 39/3 west to 44/5+313 falls within the Zigzag Ranger District of the Mt. Hood National Forest, Clackamas County, Oregon. All work conducted

385

Measurements of electromagnetic properties of LCT (Large Coil Task) coils in IFSMTF (International Fusion Superconducting Magnet Test Facility)  

SciTech Connect (OSTI)

Participants in the international Large Coil Task (LCT) have designed, built, and tested six different toroidal field coils. Each coil has a 2.5- by 3.5-m, D-shaped bore and a current between 10 and 18 kA and is designed to demonstrate stable operation at 8 T, with a superimposed averaged pulsed field of 0.14 T in 1.0 s and simulated nuclear heating. Testing of the full six-coil toroidal array began early in 1986 and was successfully completed on September 3, 1987, in the International Fusion Superconducting Magnet Test Facility (IFSMTF) at Oak Ridge National Laboratory (ORNL). This paper summarizes electromagnetic properties of LCT coils measured in different modes of energization and fast dump. Effects of mutual coupling and induced eddy currents are analyzed and discussed. Measurements of the ac loss caused by the superimposed pulsed fields are summarized. Finally, the interpretation of the test results and their relevance to practical fusion are presented. 11 refs., 10 figs., 4 tab.

Shen, S.S.; Baylor, L.R.; Dresner, L.; Fehling, D.T.; Lubell, M.S.; Lue, J.W.; Luton, J.N.; McManamy, T.J.; Wilson, C.T.; Wintenberg, R.E.

1987-01-01T23:59:59.000Z

386

Flaws Identification Using Eddy Current Differential Transducer and Artificial Neural Networks  

SciTech Connect (OSTI)

In this paper we present a multi-frequency excitation eddy current differential transducer and dynamic neural models which were used to detect and identify artificial flaws in thin conducting plates. Plates are made of Inconel600. EDM notches have relative depth from 10% to 80% and length from 2 mm to 7 mm. All flaws were located on the opposite surface of the examined specimen. Measured signals were used as input for training and verifying dynamic neural networks with a moving window. Wide range of ANN (Artificial Neural Network) structures are examined for different window length and different number of frequency components in excitation signal. Observed trends are presented in this paper.

Chady, T.; Lopato, P. [Szczecin University of Technology. al Piastow 17, 70-310 Szczecin (Poland)

2006-03-06T23:59:59.000Z

387

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

388

LES Modeling for IC Engines  

Broader source: Energy.gov [DOE]

Large eddy simulation offers better accuracy and sensitivity to study cyclic variability, mode transition and mixing effects in engine design and operation

389

Sandia National Laboratories: Transportation Energy  

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

Facilities, News, News & Events, Research & Capabilities, Systems Analysis, Transportation Energy By combining advanced theory and high-fidelity large eddy simulation,...

390

ARM - Data Announcements Article  

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

neutral interface for comparison in fine detail of high-resolution large eddy simulation model output with representative observations through radar Doppler spectra forward...

391

ARM - Publications: Science Team Meeting Documents  

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

statistical properties of several cumulus cloud scenes created by a large eddy simulation model. Progressively greater degrees of tilt and stretching were imposed on these...

392

ARM - Publications: Science Team Meeting Documents  

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

measurements were based on four-dimensional cloud fields produced by a large eddy simulation model. In particular, we demonstrated that 15-minute averages of frequently sampled...

393

Taking the 'Large' out of Large Hadron Collider: Computational Breakthrough  

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

Home » News & Publications » News » Science News » Taking the 'Large' out of Large Hadron Collider Taking the 'Large' out of Large Hadron Collider Computational breakthrough hastens modeling of 'tabletop accelerators' August 9, 2010 | Tags: Accelerator Science Contact: Margie Wylie | mwylie@lbl.gov | 510-486-7421 mori1 This 3D simulation shows how laser pulses create plasma wakes that propel electrons forward, much as a surfer is propelled forward by an ocean wave. Laser wakefield acceleration promises electron accelerators that are thousands of times more powerful than, yet a fraction the size of, conventional radio frequency devices. Particle accelerators like the Large Hadron Collider (LHC) at CERN are the big rock stars of high-energy physics-really big. The LHC cost nearly

394

Direct Simulations of Wind-Driven Breaking Ocean Waves with Data Assimilation  

E-Print Network [OSTI]

A formulation is developed to assimilate ocean-wave data into the Numerical Flow Analysis (NFA) code. NFA is a Cartesian-based implicit Large-Eddy Simulation (LES) code with Volume of Fluid (VOF) interface capturing. The sequential assimilation of data into NFA permits detailed analysis of ocean-wave physics with higher bandwidths than is possible using either other formulations, such as High-Order Spectral (HOS) methods, or field measurements. A framework is provided for assimilating the wavy and vortical portions of the flow. Nudging is used to assimilate wave data at low wavenumbers, and the wave data at high wavenumbers form naturally through nonlinear interactions, wave breaking, and wind forcing. Similarly, the vertical profiles of the mean vortical flow in the wind and the wind drift are nudged, and the turbulent fluctuations are allowed to form naturally. As a demonstration, the results of a HOS of a JONSWAP wave spectrum are assimilated to study short-crested seas in equilibrium with the wind. Log pr...

Dommermuth, Douglas G; Tran, Vu H; Valenciano, Miguel A

2014-01-01T23:59:59.000Z

395

Modeling & Simulation  

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

Modeling & Simulation Modeling & Simulation Research into alternative forms of energy, especially energy security, is one of the major national security imperatives of this...

396

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

397

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

398

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

399

Sorption-caused attenuation and delay of water-vapor signals in eddy-covariance sampling tubes and filters  

Science Journals Connector (OSTI)

Adsorption and desorption (together sorption) processes in sampling tubes and filters of eddy-covariance stations cause attenuation and delay of water-vapor signals, leading to underestimation of water-vapor fluxes by tens of per cent. The aim of ...

Annika Nordbo; Pekka Keklinen; Erkki Siivola; Ivan Mammarella; Jussi Timonen; Timo Vesala

400

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

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

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

402

A Portable Eddy Covariance System for the Measurement of EcosystemAtmosphere Exchange of CO2, Water Vapor, and Energy  

Science Journals Connector (OSTI)

To facilitate the study of flux heterogeneity within a region, the authors have designed and field-tested a portable eddy covariance system to measure exchange of CO2, water vapor, and energy between the land surface and the atmosphere. The ...

D. P. Billesbach; M. L. Fischer; M. S. Torn; J. A. Berry

2004-04-01T23:59:59.000Z

403

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

404

Eddy-Mediated Regime Transitions in the Seasonal Cycle of a Hadley Circulation and Implications for Monsoon Dynamics  

E-Print Network [OSTI]

Eddy-Mediated Regime Transitions in the Seasonal Cycle of a Hadley Circulation and Implications symmetric boundary conditions, the Hadley cells undergo transitions between two regimes distinguishable. The center of the summer and equinox Hadley cell lies in a latitude zone of upper-level westerlies

Bordoni, Simona

405

The Interannual Relationship between the Latitude of the Eddy-Driven Jet and the Edge of the Hadley Cell  

Science Journals Connector (OSTI)

A strong correlation between the latitudes of the eddy-driven jet and of the Hadley cell edge, on interannual time scales, is found to exist during austral summer, in both the NCEPNCAR reanalysis and the models participating in the Coupled Model ...

Sarah M. Kang; Lorenzo M. Polvani

2011-01-01T23:59:59.000Z

406

Regime Transitions of Steady and Time-Dependent Hadley Circulations: Comparison of Axisymmetric and Eddy-Permitting Simulations  

E-Print Network [OSTI]

Regime Transitions of Steady and Time-Dependent Hadley Circulations: Comparison of Axisymmetric August 2009, in final form 25 November 2009) ABSTRACT Steady-state and time-dependent Hadley circulations is progressively displaced off the equator or varied in time to study how the Hadley circulation responds

Bordoni, Simona

407

Regime transitions of steady and time-dependent Hadley circulations: Comparison of axisymmetric and eddy-permitting simulations  

E-Print Network [OSTI]

Regime transitions of steady and time-dependent Hadley circulations: Comparison of axisymmetric of the Atmospheric Sciences. Revised 25 November 2009) ABSTRACT Steady-state and time-dependent Hadley circulations is progressively displaced off the equator or varied in time to study how the Hadley circulation responds

Heaton, Thomas H.

408

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

409

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

410

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

411

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

412

Running Large Scale Jobs  

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

Running Large Scale Jobs Running Large Scale Jobs Users face various challenges with running and scaling large scale jobs on peta-scale production systems. For example, certain...

413

Large power grid analysis using domain decomposition  

E-Print Network [OSTI]

Large power grid analysis using domain decomposition Quming Zhou, Kai Sun, Kartik Mohanram, Danny C referred to as the power grid. The power grid for a modern integrated circuit may consist of several grid is traditionally described as a large-scale linear system. Simulation of power grids usually

Mohanram, Kartik

414

Challenges in Merger Simulation Analysis  

E-Print Network [OSTI]

In this paper, we share our experience with merger simulations using a Random Coefficient Logit model on the demand side and assuming a static Bertrand game on the supply side. Drawing largely from our work in Knittel and ...

Knittel, Christopher Roland

415

Simulating atmosphere flow for wind energy applications with WRF-LES  

SciTech Connect (OSTI)

Forecasts of available wind energy resources at high spatial resolution enable users to site wind turbines in optimal locations, to forecast available resources for integration into power grids, to schedule maintenance on wind energy facilities, and to define design criteria for next-generation turbines. This array of research needs implies that an appropriate forecasting tool must be able to account for mesoscale processes like frontal passages, surface-atmosphere interactions inducing local-scale circulations, and the microscale effects of atmospheric stability such as breaking Kelvin-Helmholtz billows. This range of scales and processes demands a mesoscale model with large-eddy simulation (LES) capabilities which can also account for varying atmospheric stability. Numerical weather prediction models, such as the Weather and Research Forecasting model (WRF), excel at predicting synoptic and mesoscale phenomena. With grid spacings of less than 1 km (as is often required for wind energy applications), however, the limits of WRF's subfilter scale (SFS) turbulence parameterizations are exposed, and fundamental problems arise, associated with modeling the scales of motion between those which LES can represent and those for which large-scale PBL parameterizations apply. To address these issues, we have implemented significant modifications to the ARW core of the Weather Research and Forecasting model, including the Nonlinear Backscatter model with Anisotropy (NBA) SFS model following Kosovic (1997) and an explicit filtering and reconstruction technique to compute the Resolvable Subfilter-Scale (RSFS) stresses (following Chow et al, 2005).We are also modifying WRF's terrain-following coordinate system by implementing an immersed boundary method (IBM) approach to account for the effects of complex terrain. Companion papers presenting idealized simulations with NBA-RSFS-WRF (Mirocha et al.) and IBM-WRF (K. A. Lundquist et al.) are also presented. Observations of flow through the Altamont Pass (Northern California) wind farm are available for validation of the WRF modeling tool for wind energy applications. In this presentation, we use these data to evaluate simulations using the NBA-RSFS-WRF tool in multiple configurations. We vary nesting capabilities, multiple levels of RSFS reconstruction, SFS turbulence models (the new NBA turbulence model versus existing WRF SFS turbulence models) to illustrate the capabilities of the modeling tool and to prioritize recommendations for operational uses. Nested simulations which capture both significant mesoscale processes as well as local-scale stable boundary layer effects are required to effectively predict available wind resources at turbine height.

Lundquist, J K; Mirocha, J D; Chow, F K; Kosovic, B; Lundquist, K A

2008-01-14T23:59:59.000Z

416

Model simulations on the long-term dispersal of 137Cs released into the Pacific Ocean off Fukushima  

Science Journals Connector (OSTI)

A sequence of global ocean circulation models, with horizontal mesh sizes of 0.5, 0.25and 0.1, are used to estimate the long-term dispersion by ocean currents and mesoscale eddies of a slowly decaying tracer (half-life of 30years, comparable to that of 137Cs) from the local waters off the Fukushima Dai-ichi Nuclear Power Plants. The tracer was continuously injected into the coastal waters over some weeks; its subsequent spreading and dilution in the Pacific Ocean was then simulated for 10years. The simulations do not include any data assimilation, and thus, do not account for the actual state of the local ocean currents during the release of highly contaminated water from the damaged plants in MarchApril 2011. An ensemble differing in initial current distributions illustrates their importance for the tracer patterns evolving during the first months, but suggests a minor relevance for the large-scale tracer distributions after 23years. By then the tracer cloud has penetrated to depths of more than 400m, spanning the western and central North Pacific between 25N and 55N, leading to a rapid dilution of concentrations. The rate of dilution declines in the following years, while the main tracer patch propagates eastward across the Pacific Ocean, reaching the coastal waters of North America after about 56years. Tentatively assuming a value of 10PBq for the net 137Cs input during the first weeks after the Fukushima incident, the simulation suggests a rapid dilution of peak radioactivity values to about 10Bqm?3 during the first two years, followed by a gradual decline to 12Bqm?3 over the next 47 years. The total peak radioactivity levels would then still be about twice the pre-Fukushima values.

Erik Behrens; Franziska U Schwarzkopf; Joke F Lbbecke; Claus W Bning

2012-01-01T23:59:59.000Z

417

Simulation Tools  

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

Building simulation tool screen capture Building simulation tool screen capture Simulation Tools Researchers develop whole-building energy simulation software programs that allow architects and building engineers to design or retrofit buildings for maximum energy efficiency and occupant comfort. Programs developed by researchers include: the EnergyPlus whole building simulation program, the Modelica Buildings library for rapid prototyping and controls design, the Building Controls Virtual Test Bed for co-simulation and for model-based operation, and the GenOpt generic optimization program. Contacts Philip Haves PHaves@lbl.gov (510) 486-6512 Michael Wetter MWetter@lbl.gov (510) 486-6990 Links Simulation Research Group Batteries and Fuel Cells Buildings Energy Efficiency Applications Commercial Buildings

418

Distributed Simulation and Simulation Practice  

Science Journals Connector (OSTI)

The possibilities of distributed simulation have been discussed for well over a decade, yet there is only limited evidence of its implementation, particularly within industry. The reasons for this are discussed by identifying the potential applications ... Keywords: Distributed simulation, complexity, innovation, simulation practice

Stewart Robinson

2005-01-01T23:59:59.000Z

419

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.

420

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

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.


421

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. Motivation and objectives This report discusses our progress towards developing a numerical algorithm, and solver capable of performing large-eddy simulation in geometries as complex as the combustor of a gas-turbine

Apte, Sourabh V.

422

Automated Link 16 Testing using DEVS and XML Eddie Mak, Saurabh Mittal, Moon-Ho Hwang  

E-Print Network [OSTI]

Center of Integrative Modeling and Simulation (ACIMS) ECE Department, University of Arizona Tucson, AZ in order to maintain their effectiveness. DoD acquisition policy requires using modeling and simulation, the DEVS modeling and simulation (M&S) framework, the System Entity Structure (SES), and the Extensible

423

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

424

The Dimits Shift in More Realistic Gyrokinetic Plasma Turbulence Simulations  

SciTech Connect (OSTI)

In simulations of turbulent plasma transport due to long wavelength, (k?pi ? 1), electrostatic drift-type instabilities we find that a nonlinear upshift of the effective threshold persists. This `Dimits shift' represents the difference between the linear threshold, at the onset of instability, and the nonlinear threshold, where transport increases suddenly as the driving temperature gradient is increased. As the drive increases, the magnitudes of turbulent eddies and zonal ows grow until the zonal flows become nonlinearly unstable to 'tertiary' modes and their sheared ows no longer grow fast enough to strongly limit eddy size. The tertiary mode threshold sets the effective nonlinear threshold for the heat transport, and the Dimits shift arises when this occurs at a zonal flow magnitude greater than that needed to limit transport near the linear threshold. Nextgeneration tokamaks will likely benefit from the higher effective threshold for turbulent transport, and transport models should incorporate suitable corrections to linear thresholds. These gyrokinetic simulations are more realistic than previous reports of a Dimits shift because they include nonadiabatic electron dynamics, strong collisional damping of zonal flows, and finite electron and ion collisionality together with realistic shaped magnetic geometry. Reversing previously reported results based on idealized adiabatic electrons, we find that increasing collisionality reduces the heat flux because collisionality reduces the nonadiabatic electron drive.

D.R. Mikkelsen and W. Dorland

2008-07-23T23:59:59.000Z

425

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

426

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

427

Single molecule pulling with large time steps  

Science Journals Connector (OSTI)

Recently, we presented a generalization of the Jarzynski nonequilibrium work theorem for phase space mappings. The formalism shows that one can determine free energy differences from approximate trajectories obtained from molecular dynamics simulations in which very large time steps are used. In this work we test the method by simulating the force-induced unfolding of a deca-alanine helix in vacuum. The excellent agreement between results obtained with a small, conservative time step of 0.5fs and results obtained with a time step of 3.2fs (i.e., close to the stability limit) indicates that the large-time-step approach is practical for such complex biomolecules. We further adapt the method of Hummer and Szabo for the simulation of single molecule force spectroscopy experiments to the large-time-step method. While trajectories generated with large steps are approximate and may be unphysicalin the simulations presented here we observe a violation of the equipartition theoremthe computed free energies are exact in principle. In terms of efficiency, the optimum time step for the unfolding simulations lies in the range 13fs.

Harald Oberhofer; Christoph Dellago; Stefan Boresch

2007-06-06T23:59:59.000Z

428

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

429

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

430

Estimating dependence of the turbulent length scales on model resolution based on a priori analysis  

Science Journals Connector (OSTI)

The Reynolds Averaged Navier-Stokes Simulation (RANS) and the Large-Eddy Simulation (LES) have been widely used to parameterize unresolved turbulent motions for the atmospheric boundary layer. However, there is an intermediate model resolution, ...

Yuji KITAMURA

431

Scaling Laws for the Heterogeneously Heated Free Convective Boundary Layer  

Science Journals Connector (OSTI)

The heterogeneously heated free convective boundary layer (CBL) is investigated by means of dimensional analysis and results from large-eddy simulations (LES) and direct numerical simulations (DNS). The investigated physical model is a CBL that ...

Chiel C. van Heerwaarden; Juan Pedro Mellado; Alberto De Lozar

2014-11-01T23:59:59.000Z

432

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

433

Magnetohydrodynamic Turbulence Simulations on the Earth Simulator Using the Lattice Boltzmann  

E-Print Network [OSTI]

Magnetohydrodynamic Turbulence Simulations on the Earth Simulator Using the Lattice Boltzmann Method ABSTRACT Highly optimized large-scale lattice Boltzmann simulations of 3D magnetohydrodynamic-Krylov algorithms. Lattice Boltzmann (LB) schemes are an alternate approach that circumvent the resolution problems

Oliker, Leonid

434

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

435

On the Feasibility of Eddy Current Characterization of the Near-Surface Residual Stress Distribution in Nickel-Base Superalloys  

SciTech Connect (OSTI)

In light of its frequency-dependent penetration depth, the measurement of eddy current conductivity has been suggested as a possible means to allow the nondestructive evaluation of subsurface residual stresses in shot-peened specimens. This technique is based on the so-called electroelastic effect, i.e., the stress-dependence of the electrical conductivity. Unfortunately, the relatively small ({approx}1%) change in electrical conductivity caused by the presence of compressive residual stresses is often distorted, or even completely overshadowed, by the accompanying conductivity loss caused by cold work and surface roughness effects. Recently, it was observed that, in contrast with most other materials, shot-peened Waspaloy and IN100 specimens exhibit an apparent increase in electrical conductivity at increasing inspection frequencies. This observation by itself indicates that in these materials the measured conductivity change is probably dominated by residual stress effects, since both surface roughness and increased dislocation density are known to decrease rather than increase the conductivity and the presence of crystallographic texture does not affect the electrical conductivity of these materials, which crystallize in cubic symmetry. Our preliminary experiments indicate that probably there exists a unique 'window of opportunity' for eddy current NDE in nickel-base superalloys. We identified five major effects that contribute to this fortunate constellation of material properties, which will be reviewed in this presentation.

Blodgett, Mark P. [Metals, Ceramics, and NDE Division, AFRL, Wright-Patterson Air Force Base, Dayton, Ohio 45433-7817 (United States); Nagy, Peter B. [Department of Aerospace Engineering and Engineering Mechanics, University of Cincinnati, Cincinnati, Ohio 45221-0070 (United States)

2004-02-26T23:59:59.000Z

436

Comprehensive Approaches to Multiphase Flows in Geophysics - Application to nonisothermal, nonhomogenous, unsteady, large-scale, turbulent dusty clouds I. Hydrodynamic and Thermodynamic RANS and LES Models  

SciTech Connect (OSTI)

The objective of this manuscript is to fully derive a geophysical multiphase model able to ''accommodate'' different multiphase turbulence approaches; viz., the Reynolds Averaged Navier-Stokes (RANS), the Large Eddy Simulation (LES), or hybrid RANSLES. This manuscript is the first part of a larger geophysical multiphase project--lead by LANL--that aims to develop comprehensive modeling tools for large-scale, atmospheric, transient-buoyancy dusty jets and plume (e.g., plinian clouds, nuclear ''mushrooms'', ''supercell'' forest fire plumes) and for boundary-dominated geophysical multiphase gravity currents (e.g., dusty surges, diluted pyroclastic flows, dusty gravity currents in street canyons). LES is a partially deterministic approach constructed on either a spatial- or a temporal-separation between the large and small scales of the flow, whereas RANS is an entirely probabilistic approach constructed on a statistical separation between an ensemble-averaged mean and higher-order statistical moments (the so-called ''fluctuating parts''). Within this specific multiphase context, both turbulence approaches are built up upon the same phasic binary-valued ''function of presence''. This function of presence formally describes the occurrence--or not--of any phase at a given position and time and, therefore, allows to derive the same basic multiphase Navier-Stokes model for either the RANS or the LES frameworks. The only differences between these turbulence frameworks are the closures for the various ''turbulence'' terms involving the unknown variables from the fluctuating (RANS) or from the subgrid (LES) parts. Even though the hydrodynamic and thermodynamic models for RANS and LES have the same set of Partial Differential Equations, the physical interpretations of these PDEs cannot be the same, i.e., RANS models an averaged field, while LES simulates a filtered field. In this manuscript, we also demonstrate that this multiphase model fully fulfills the second law of thermodynamics and fulfills the necessary requirements for a well-posed initial-value problem. In the next manuscripts, we will further develop specific closures for multiphase RANS, LES, and hybrid-LES.

S. Dartevelle

2005-09-05T23:59:59.000Z

437

Hybrid LESRANS: back scatter from a scale-similarity model used as forcing  

Science Journals Connector (OSTI)

...model is used as forcing in hybrid LES-RANS, stimulating the...support by Swedish National Infrastructure for Computing (SNIC) for...issues/large_eddies.xhtml Hybrid LES-RANS: back scatter from...other way around as forcing in hybrid large eddy simulation-Reynolds-averaged...

2009-01-01T23:59:59.000Z

438

Faster PDE-based simulations using robust composite linear solvers  

Science Journals Connector (OSTI)

Many large-scale scientific simulations require the solution of nonlinear partial differential equations (PDEs). The effective solution of such nonlinear PDEs depends to a large extent on efficient and robust sparse linear system solution. In this paper, ... Keywords: Newton-Krylov methods, composite methods, large-scale PDE-based simulations, multi-algorithms, sparse linear solution

S. Bhowmick; P. Raghavan; L. McInnes; B. Norris

2004-04-01T23:59:59.000Z

439

Cosmological Simulations for Large-Scale Sky Surveys | Argonne...  

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

on all HPC systems. In particular, on the IBM BGQ system, HACC has reached very high levels of performance-almost 14 petaflops (the highest ever recorded by a science code)...

440

Simulation of SMES connected to a large scale system  

E-Print Network [OSTI]

Transaction on Magnetics, Vol. MAG-17, No. 5, September 1981. [13] R. I. Schermer, et al. , "Design and Operation of the 30-MJ Superconducting Magnetic Energy Storage System of the Bonneville Power Administration Bus, " Los Alamos National Laboratory... Transaction on Magnetics, Vol. MAG-17, No. 5, September 1981. [13] R. I. Schermer, et al. , "Design and Operation of the 30-MJ Superconducting Magnetic Energy Storage System of the Bonneville Power Administration Bus, " Los Alamos National Laboratory...

Gulde, James Ernst

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.


441

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...

442

The Application of Neural Networks to Electric Power Grid Simulation  

Science Journals Connector (OSTI)

A neural network approach is being developed to enable real time simulations for large scale dynamic system simulations of the electric power grid. If the grid is decomposed into several...

Emily T. Swain; Yunlin Xu; Rong Gao

2006-01-01T23:59:59.000Z

443

Controlling individual agents in high-density crowd simulation  

Science Journals Connector (OSTI)

Simulating the motion of realistic, large, dense crowds of autonomous agents is still a challenge for the computer graphics community. Typical approaches either resemble particle simulations (where agents lack orientation controls) or are conservative ...

N. Pelechano; J. M. Allbeck; N. I. Badler

2007-08-01T23:59:59.000Z

444

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

445

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

446

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

447

Satellite-Based Modeling of the Carbon Fluxes in Mature Black Spruce Forests in Alaska: A Synthesis of the Eddy Covariance Data and Satellite Remote Sensing Data  

Science Journals Connector (OSTI)

Scaling up of observed point data to estimate regional carbon fluxes is an important issue in the context of the global terrestrial carbon cycle. In this study, the authors proposed a new model to scale up the eddy covariance data to estimate ...

Masahito Ueyama; Yoshinobu Harazono; Kazuhito Ichii

2010-10-01T23:59:59.000Z

448

Subinertial dynamics of densitydriven flows in a continuously stratified fluid on a sloping bottom. II. Isolated eddies and radiating cold domes  

Science Journals Connector (OSTI)

...eddies and radiating cold domes Francis J. Poulin Gordon E. Swaters Applied Mathematics...and radiating cold domes By Francis J. Poulin and Gordon E. Swaters Applied Mathematics...Introduction This paper is a continuation of Poulin & Swaters (1999), hereafter referred...

1999-01-01T23:59:59.000Z

449

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.

450

Meet with Large Businesses  

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

Meet with Large Businesses Meet with Large Businesses and learn about upcoming acquisitions! * Federal Energy Management Program (FEMP) * National Renewable Energy Laboratory (NREL) * Small Business Administration (SBA) * U.S. Department of Energy / Energy, Efficiency, and Renewable Energy (EERE) * U.S. Department of Energy / Golden Field Office (GFO) * Western Area Power Administration (WAPA) * Colorado Procurement Technical Assistance Center (PTAC)

451

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

452

Numerical Simulation in a Supercirtical CFB Boiler  

Science Journals Connector (OSTI)

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

Yanjun Zhang; Xiang Gaol; Zhongyang Luo

2010-01-01T23:59:59.000Z

453

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

454

Model Validation with Hybrid Dynamic Simulation  

SciTech Connect (OSTI)

AbstractModel 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

455

Building Performance Simulation  

E-Print Network [OSTI]

Y (2008). DeSTAn integrated building simulation toolkit,Part ? : Fundamentals. Building Simulation, 1: 95 ? 110.Y (2008). DeSTAn integrated building simulation toolkit,

Hong, Tianzhen

2014-01-01T23:59:59.000Z

456

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

457

Digestion Simulations  

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

Digestion Simulations Digestion Simulations Name: Lisa Location: N/A Country: N/A Date: N/A Question: My 5th grade students are beginning an experiment next week and their hypothesis involves edibility(edibleness?). Is there a way to replicate the stomach in, say, a bottle?? Are there ways to test for edibleness(?) without actually ingesting the experiment yourself? Replies: I would not recommend the idea of a bottle stomach. The stomach digests only proteins anyway with HCl [pH 1.0] which is very, very strong acid that will burn seriously if in contact with skin. The intestine is just as much responsible for digestion of lipids [bile], carbohydrates and remaining proteins using enzymes, many of these you do not want to be handling, let alone purchase. As a high school teacher, I have lab exercises dealing with digestion, but I can not recommend any of these unless you are set up with a functional science laboratory and all the safety equipment necessary.

458

COLLABORATIVE: FUSION SIMULATION PROGRAM  

SciTech Connect (OSTI)

New York University, Courant Institute of Mathematical Sciences, participated in the ???¢????????Fusion Simulation Program (FSP) Planning Activities???¢??????? [http://www.pppl.gov/fsp], with C.S. Chang as the institutional PI. FSP???¢????????s mission was to enable scientific discovery of important new plasma phenomena with associated understanding that emerges only upon integration. This requires developing a predictive integrated simulation capability for magnetically-confined fusion plasmas that are properly validated against experiments in regimes relevant for producing practical fusion energy. Specific institutional goal of the New York University was to participate in the planning of the edge integrated simulation, with emphasis on the usage of large scale HPCs, in connection with the SciDAC CPES project which the PI was leading. New York University successfully completed its mission by participating in the various planning activities, including the edge physics integration, the edge science drivers, and the mathematical verification. The activity resulted in the combined report that can be found in http://www.pppl.gov/fsp/Overview.html. Participation and presentations as part of this project are listed in a separation file.

Chang, Choong Seock

2012-06-05T23:59:59.000Z

459

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

460

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

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

On the Evolution of Thermonuclear Flames on Large Scales  

Science Journals Connector (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 in 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 processes and basic characteristics of the flow are discussed. We find that the flame surface creation strength is associated with the Rayleigh-Taylor timescale. Also, in fully developed turbulence, the flame surface destruction strength scales as 1/L3, where L is the turbulent driving scale. The results of our investigation provide support for Khokhlov's self-regulating model of turbulent thermonuclear flames. Based on these results, one can revise and extend the original model. The revision uses a local description of the flame surface enhancement and the evolution of the flame surface since the onset of turbulence, rendering it free from the assumption of an instantaneous steady state of turbulence. This new model can be applied to the initial transient phase of the flame evolution, where the self-regulation mechanism yet to be fully established. Details of this new model will be presented in a forthcoming paper.

Ju Zhang; O. E. Bronson Messer; Alexei M. Khokhlov; Tomasz Plewa

2007-01-01T23:59:59.000Z

462

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

463

The Large Hadron Collider  

Science Journals Connector (OSTI)

...fully from the space available in...the machine construction. The superconducting...for a single sector, the whole...therefore, as the heating increases...was made, a sector was powered...is a slight heating during ramp...Collider. | The construction of the Large...the limited space available in...

2012-01-01T23:59:59.000Z

464

Supplement Analysis for the Transmission System Vegetation Management Program FEIS (DOE/EIS-0285/SA-132 (Big Eddy-Ostrander #1)(3/19/03)  

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

9, 2003 9, 2003 REPLY TO ATTN OF: KEP-4 SUBJECT: Supplement Analysis for the Transmission System Vegetation Management Program FEIS (DOE/EIS-0285/SA-132 (Big Eddy-Ostrander #1) Libby Johnson Natural Resource Specialist - TFR/THE DALLES Proposed Action: Vegetation Management for portion of the Big Eddy - Ostrander #1 500 kV transmission line located from tower structure 31/2 to 39/3. Location: Project location is in BPA Redmond Region in Hood River County, Oregon. Proposed by: Bonneville Power Administration (BPA). Description of the Proposal: BPA proposes to clear targeted vegetation within the Right-of- Ways along access roads and around towers that may impede the operation and maintenance of the subject transmission lines. See Section 1.4 of the attached checklists for a complete

465

Simulation speedup of ns-3 using checkpoint and restore  

Science Journals Connector (OSTI)

Given that large-scale network simulations are a significant part of active research [6], and that such simulations are known to be computationally and resource intensive, it is still of interest to find innovative ways to achieve faster execution times ... Keywords: DMTCP, MPI, checkpoint, ns-3, restore, simulation

Kyle Harrigan; George Riley

2014-05-01T23:59:59.000Z

466

Grid resolution effects on LES of a piloted methane-air flame K. A. Kemenov  

E-Print Network [OSTI]

not only for canonical geome- tries like laboratory jet flames but also for complex ones like gas-turbine in the flame shows some residual grid dependence. Introduction Large Eddy Simulation (LES) has proved

467

LES of a Spatially Developing Atmospheric Boundary Layer: Application of a Fringe Method for the Stratocumulus to Shallow Cumulus Cloud Transition  

Science Journals Connector (OSTI)

An arrangement of a large-eddy simulation (LES) is described that facilitates a spatially developing thermally stratified atmospheric boundary layer (ABL). When the inflow and outflow boundary conditions are specified, the LES of stably stratified ...

M. Inoue; G. Matheou; J. Teixeira

2014-09-01T23:59:59.000Z

468

Lagrangian investigation of the precipitation efficiency of convective clouds  

Science Journals Connector (OSTI)

The precipitation efficiency of cumulus-congestus clouds is investigated with a new Lagrangian particle framework for large-eddy simulations. The framework is designed to track particles representative of individual water molecules. A Monte-Carlo ...

Wolfgang Langhans; Kyongmin Yeo; David M. Romps

469

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...

470

Development of a genetic algorithm tracking technique for the particle image velocimetry and comparison with other tracking models  

E-Print Network [OSTI]

particles between sequential frames. The new tracking method was compared with three other existing tracking methods to evaluate their efficiency, i.e., reliability and yield. Synthetic data from a Large Eddy Simulation (LES) computational fluid dynamic...

Yoon, Churl

2012-06-07T23:59:59.000Z

471

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

472

Assessing net ecosystem carbon exchange of U S terrestrial ecosystems by integrating eddy covariance flux measurements and satellite observations  

SciTech Connect (OSTI)

More accurate projections of future carbon dioxide concentrations in the atmosphere and associated climate change depend on improved scientific understanding of the terrestrial carbon cycle. Despite the consensus that U.S. terrestrial ecosystems provide a carbon sink, the size, distribution, and interannual variability of this sink remain uncertain. Here we report a terrestrial carbon sink in the conterminous U.S. at 0.63 pg C yr 1 with the majority of the sink in regions dominated by evergreen and deciduous forests and savannas. This estimate is based on our continuous estimates of net ecosystem carbon exchange (NEE) with high spatial (1 km) and temporal (8-day) resolutions derived from NEE measurements from eddy covariance flux towers and wall-to-wall satellite observations from Moderate Resolution Imaging Spectroradiometer (MODIS). We find that the U.S. terrestrial ecosystems could offset a maximum of 40% of the fossil-fuel carbon emissions. Our results show that the U.S. terrestrial carbon sink varied between 0.51 and 0.70 pg C yr 1 over the period 2001 2006. The dominant sources of interannual variation of the carbon sink included extreme climate events and disturbances. Droughts in 2002 and 2006 reduced the U.S. carbon sink by 20% relative to a normal year. Disturbances including wildfires and hurricanes reduced carbon uptake or resulted in carbon release at regional scales. Our results provide an alternative, independent, and novel constraint to the U.S. terrestrial carbon sink.

Zhuang, Qianlai [Purdue University; Law, Beverly E. [Oregon State University; Baldocchi, Dennis [University of California, Berkeley; Ma, Siyan [University of California, Berkeley; Chen, Jiquan [University of Toledo, Toledo, OH; Richardson, Andrew [Harvard University; Melillo, Jerry [Marine Biological Laboratory; Davis, Ken J. [Pennsylvania State University; Hollinger, D. [USDA Forest Service; Wharton, Sonia [University of California, Davis; Falk, Matthias [University of California, Davis; Paw, U. Kyaw Tha [University of California, Davis; Oren, Ram [Duke University; Katulk, Gabriel G. [Duke University; Noormets, Asko [North Carolina State University; Fischer, Marc [Lawrence Berkeley National Laboratory (LBNL); Verma, Shashi [University of Nebraska; Suyker, A. E. [University of Nebraska, Lincoln; Cook, David R. [Argonne National Laboratory (ANL); Sun, G. [USDA Forest Service; McNulty, Steven G. [USDA Forest Service; Wofsy, Steve [Harvard University; Bolstad, Paul V [University of Minnesota; Burns, Sean [University of Colorado, Boulder; Monson, Russell K. [University of Colorado, Boulder; Curtis, Peter [Ohio State University, The, Columbus; Drake, Bert G. [Smithsonian Environmental Research Center, Edgewater, MD; Foster, David R. [Harvard University; Gu, Lianhong [ORNL; Hadley, Julian L. [Harvard University; Litvak, Marcy [University of New Mexico, Albuquerque; Martin, Timothy A. [University of Florida, Gainesville; Matamala, Roser [Argonne National Laboratory (ANL); Meyers, Tilden [NOAA, Oak Ridge, TN; Oechel, Walter C. [San Diego State University; Schmid, H. P. [Indiana University; Scott, Russell L. [USDA ARS; Torn, Margaret S. [Lawrence Berkeley National Laboratory (LBNL)

2011-01-01T23:59:59.000Z

473

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...

474

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 identication 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 identication is possible. We show that unique identication becomes less likely as p increases.

Chilton, Lawrence K.; Walsh, Stephen J.

2008-10-03T23:59:59.000Z

475

Archive Reference Buildings by Building Type: Large office | Department of  

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

Large office Large office Archive Reference Buildings by Building Type: Large office Here you will find past versions of the reference buildings for new construction commercial buildings, organized by building type and location. A summary of building types and climate zones is available for reference. Current versions are also available. You can download ZIP files that contain the following: An EnergyPlus software input file (.idf) An html file showing the results from the EnergyPlus simulation (.html) A spreadsheet that summarizes the inputs and results for each location (.xls) The EnergyPlus TMY2 weather file (.epw). benchmark-v1.0_3.0-large_office.zip benchmark-v1.1_3.1-large_office.zip benchmark-new-v1.2_4.0-large_office.zip More Documents & Publications Archive Reference Buildings by Building Type: Large Hotel

476

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 1320 T. The latest generations of fusion machines producing hot plasma also use large superconducting magnet systems.

Vdrine, P

2014-01-01T23:59:59.000Z

477

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

478

On the nature of oceanic eddies shed by the Island of Gran Canaria  

Science Journals Connector (OSTI)

We use hydrographic and buoy data to compare the initial temperature fields and Lagrangian evolution of water parcels in two vortices generated by the southward flowing Canary Current passing around the island of Gran Canaria Island. One vortex is anticyclonic, shed in June 1998 as the result of an incident current of about 0.05ms?1, and the second one is cyclonic, shed in June 2005 with the impinging current estimated as 0.03ms?1. The two vortices exhibit contrasting characteristics yet display some important similarities. The isopycnals are depressed in the core of the anticyclonic vortex, at least down to a depth of 700m, whilst they dome up in the core of the cyclonic vortex but only down to 450m. In the top 300m the depression/doming of the isotherms is similar for both vortices, with a maximum vertical displacement of the isotherm of about 80m, which correspond to temperature anomalies of some 2.5C at a given depth. A simple method is developed to obtain the initial orbital velocity field from the temperature data, from which we estimate peak values of 0.7 and 0.5ms?1 for the anticyclonic and cyclonic vortices, respectively. The buoys, three for the anticyclonic vortex and two for the cyclonic one, were drougued at 100m depth, below the surface mixed layer, and their initial velocities are consistent with the above values. In both vortices, the buoys revolve either within a central core, where the rotation rate remains stable and large for several weeks, or in an outer ring, where the rotation rate is significantly smaller and displays large radial fluctuations. Within the inner core the anticyclonic vortex has significant inward radial velocity, while the cyclonic vortex has near-zero radial mean motions. The cyclonic vortex rotates more slowly than the anticyclonic, their initial periods being 4.5 and 2.5 days, respectively. A simple axisymmetric model with radial diffusion (coefficient Kh?25m2s?1) and advection reproduces the observations reasonably well, the diffusive effect being more important than that resulting from the observed radial advection. The model also supports the hypothesis that the rotation rate of cyclonic vortices is less than that of anticyclonic vortices, as otherwise they would become inertially unstable. Both the buoys data and sea surface temperature images confirm that the vortices evolve from youth to maturity, as the cores shrink and the outer rings expands, and then to a decay stage, as the core rotation rates decrease, though frequent interactions with other mesoscale structures result in more accelerated aging. Despite these interaction they last many months as coherent structures south of the Canary Islands.

P. Sangr; M. Auladell; A. Marrero-Daz; J.L. Pelegr; E. Fraile-Nuez; A. Rodrguez-Santana; J.M. Martn; E. Mason; A. Hernndez-Guerra

2007-01-01T23:59:59.000Z

479

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

480

Mixed Mode Simulation Tools  

E-Print Network [OSTI]

ANSYS CFX, ANSYS Fluent, Autodesk Simulation CFD (formerly CFDesign), Autodesk Vasari, FloVENT, Flowdesigner,

Gandhi, Priya; Brager, Gail; Dutton, Spencer

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.


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 computing 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.

Gary A. Pope; Kamy Sepehrnoori; Mojdeh Delshad

2002-09-30T23:59:59.000Z

482

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

483

Modeling needs for very large systems.  

SciTech Connect (OSTI)

Most system performance models assume a point measurement for irradiance and that, except for the impact of shading from nearby obstacles, incident irradiance is uniform across the array. Module temperature is also assumed to be uniform across the array. For small arrays and hourly-averaged simulations, this may be a reasonable assumption. Stein is conducting research to characterize variability in large systems and to develop models that can better accommodate large system factors. In large, multi-MW arrays, passing clouds may block sunlight from a portion of the array but never affect another portion. Figure 22 shows that two irradiance measurements at opposite ends of a multi-MW PV plant appear to have similar irradiance (left), but in fact the irradiance is not always the same (right). Module temperature may also vary across the array, with modules on the edges being cooler because they have greater wind exposure. Large arrays will also have long wire runs and will be subject to associated losses. Soiling patterns may also vary, with modules closer to the source of soiling, such as an agricultural field, receiving more dust load. One of the primary concerns associated with this effort is how to work with integrators to gain access to better and more comprehensive data for model development and validation.

Stein, Joshua S.

2010-10-01T23:59:59.000Z

484

Robot Hardware Simulator  

E-Print Network [OSTI]

Robotics Simulator is to perform simulations of many heterogeneous types of robots all working within a single, virtual environment. The main components of this project are Robot Simulator, Environment Control Panel and Environment Simulator. Robot simulator consists of three parts: a robot hardware simulator, a robot control program, which will be user supplied, and an environment-based robot object. Robot control program can work with various robot hardware simulators via standard API. The robot hardware simulator will interface to the environment via requests for data from its sensor or requests for action from its actuators. The environment-based robots will be responsible for controlling the individual sensors, based on robot hardware simulator requests, and providing the appropriate data to the sensors, Environment control panel will be a standalone system that connects to the environment simulator to monitor and control the current simulation The environment simulator is the central component in the system. The environment simulator is responsible for keeping track of the actual state of the environment, including each robot. The environment simulator receives requests from simulated robots to read sensors, initiate actuators, and to send and receive communication.

unknown authors

485

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

486

Archive Reference Buildings by Building Type: Large Hotel | Department of  

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

Large Hotel Large Hotel Archive Reference Buildings by Building Type: Large Hotel Here you will find past versions of the reference buildings for new construction commercial buildings, organized by building type and location. A summary of building types and climate zones is available for reference. Current versions are also available. You can download ZIP files that contain the following: An EnergyPlus software input file (.idf) An html file showing the results from the EnergyPlus simulation (.html) A spreadsheet that summarizes the inputs and results for each location (.xls) The EnergyPlus TMY2 weather file (.epw). benchmark-v1.0_3.0-large_hotel.zip benchmark-v1.1_3.1-large_hotel.zip benchmark-new-v1.2_4.0-large_hotel.zip More Documents & Publications Archive Reference Buildings by Building Type: Small Hotel

487

A Novel Simulation System for Marine Main Diesel Propulsion Remote Control  

Science Journals Connector (OSTI)

The purpose of the paper is to develop a novel simulation system for ship propulsion plant. The nonlinear mathematical model of main propulsion system of a large container ship is established, consisting of the large low speed two-stroke diesel engine, ... Keywords: simulation system, large-scale low-speed two-stroke diesel engine, marine main diesel propulsion

Yang Yang; Chen Guo; Jian-bo Sun; De-wen Yan

2011-11-01T23:59:59.000Z

488

In-situ repairs of pipelines using metal arc welding under oil (MAW-UO) aided by eddy current crack detection  

Science Journals Connector (OSTI)

Metal arc welding under oil (MAW-UO) is a new process developed to make in-situ internal repairs of in-service oil industry pipelines tanks and vessels without the need to evacuate the service from the containing fluid. High nickel alloy welding wires were used to produce a tough relatively soft austenitic weld metal; with reduced weld metal hardness porosity residual strain and cracking susceptibility. Eddy current sensors were able to detect cracks under oil which then can be repaired in-situ using MAW-UO. The in-situ under oil crack detection and arc weld repair process will be described.

2012-01-01T23:59:59.000Z

489

X/motif based relational database in digital simulators application for protective relay testing  

E-Print Network [OSTI]

With the increase in complexity of digital simulator use for protective relay testing, the large volume of data during simulation and relay testing is generated. The management of these data is a challenging problem. This thesis describes a...

Qi, Xiaoxia

2012-06-07T23:59:59.000Z

490

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

491

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

492

Miller experiments in atomistic computer simulations  

Science Journals Connector (OSTI)

...checked that the average energy of a simulation...which, under the effect of the field...and it continuously fuels the formation of more...due to catalytic effects originated on the steric...1986 ) Chemical effects of large impacts on the Earth...5131 . 20 Martins Z Price MC Goldman N Sephton...

Antonino Marco Saitta; Franz Saija

2014-01-01T23:59:59.000Z

493

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

494

Modeling open boundaries in dissipative MHD simulation  

Science Journals Connector (OSTI)

The truncation of large physical domains to concentrate computational resources is necessary or desirable in simulating many natural and man-made plasma phenomena. Three open boundary condition (BC) methods for such domain truncation of dissipative magnetohydrodynamics ... Keywords: Approximate Riemann, Artificial boundary, Calderon method, Dissipative, Lacuna, Lacunae, MHD, Magnetohydrodynamics, Non-reflecting boundary, Nonlinear, Open boundary, hyperbolic-parabolic

E. T. Meier; A. H. Glasser; V. S. Lukin; U. Shumlak

2012-04-01T23:59:59.000Z

495

Rabi multi-sector reservoir simulation model  

SciTech Connect (OSTI)

To ensure optimum ultimate recovery of the 46 meter thick oil rim of the Rabi Field in Gabon, a full field simulation model was required. Due to it`s size and complexity, with local cusping, coning and geological circumstances dominating individual well behavior, a single full field model would be too large for existing hardware. A method was developed to simulate the full field with 5 separate sector models, whilst allowing the development in one sector model to have an effect on the boundary conditions of another sector. In this manner, the 13 x 4.5 km field could be simulated with a horizontal well spacing down to 175 meter. This paper focuses on the method used to attach single 3-phase tank cells to a sector simulation grid in order to represent non-simulated parts of the field. It also describes the history matching methodology and how to run a multisector model in forecasting mode. This method can be used for any reservoir, where size and complexity require large reservoir simulation models that normally could not be modeled within the constraints of available computer facilities. Detailed studies can be conducted on specific parts of a field, whilst allowing for dynamic flow and pressure effects caused by the rest of the field.

Bruijnzeels, C.; O`Halloran, C.

1995-12-31T23:59:59.000Z

496

Model Validation with Hybrid Dynamic Simulation  

SciTech Connect (OSTI)

AbstractModel 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

497

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

498

An object-oriented paradigm for simulating postal distribution centers  

Science Journals Connector (OSTI)

Discrete-event simulation is an established tool for the design and management of large-scale mail sortation and distribution systems. Because the design of distribution facilities integrates many of the same or functionally similar components, adopting ...

K. Preston White, Jr.; Brian Barney; Scott Keller; Robert Schwieters; Jacqueline Villasenor; William S. Terry; Richard G. Fairbrother; Richard D. Saxton

2001-12-01T23:59:59.000Z

499

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

500

NREL: Computational Science - Wind Energy Simulations  

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

Wind Energy Simulations Wind Energy Simulations Scientists in the Computational Science Center at the National Renewable Energy Laboratory (NREL) are performing wind-farm computational fluid dynamics (CFD) and structural dynamics simulations that will provide a better understanding of the interactions of wind turbine wakes with one another, with the surrounding winds, and with the loads they impose on turbine blades and other components. Large-scale wind power generation deployment is a realistic and largely inevitable proposition as energy security, supply uncertainties, and global climate concerns drive the U.S. to develop diverse sources of domestic, clean, and renewable energy. The U.S. is currently on a path to produce 20% of its electricity from wind energy by 2030, which is a 10-fold increase