National Library of Energy BETA

Sample records for large-eddy simulation les

  1. Sandia Energy - Large Eddy Simulation (LES) of Engines

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

    Large Eddy Simulation (LES) of Engines Home Transportation Energy Predictive Simulation of Engines Reacting Flow Modeling Large Eddy Simulation (LES) of Engines Large Eddy...

  2. Sandia Energy - Large Eddy Simulation (LES) of Engines

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

    Large Eddy Simulation (LES) of Engines Home Transportation Energy Predictive Simulation of Engines Engine Combustion Modeling Large Eddy Simulation (LES) of Engines Large Eddy...

  3. Large Eddy Simulation (LES) of Engines

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

    Engine Combustion/Modeling/Large Eddy Simulation (LES) of Engines - Large Eddy Simulation (LES) of Enginesadmin2015-10-28T02:19:26+00:00 LES-SN-LES-Eng-Combustion-Modeling-2 The combination of High Performance Computing (HPC) and the Large Eddy Simulation (LES) technique has significant potential to provide new insights into the dynamics of IC-engine flow processes. At the CRF, we integrate the combined merits of HPC and LES in a manner that provides some of the highest-fidelity, most detailed

  4. Large Eddy Simulation (LES) of Engines

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

    Reacting Flow/Modeling/Large Eddy Simulation (LES) of Engines - Large Eddy Simulation (LES) of Enginesadmin2015-10-30T01:57:44+00:00 The combination of high-performance computing (HPC) and the large eddy simulation (LES) technique has significant potential to provide new insights into the dynamics of many types of turbulent combustion processes. The objective of LES development at the CRF is to fully integrate the combined merits of HPC and LES in a manner that provides some of the

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

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

    | Department of Energy Advanced Engine Combustion Research Large Eddy Simulation (LES) Applied to Advanced Engine Combustion Research 2012 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting PDF icon ace007_oefelein_2012_o.pdf More Documents & Publications Large Eddy Simulation (LES) Applied to Advanced Engine Combustion Research Large Eddy Simulation (LES) Applied to Low-Temperature and Diesel Engine Combustion Research

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

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

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

  7. Vehicle Technologies Office Merit Review 2015: Large Eddy Simulation (LES)

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

    Applied to Advanced Engine Combustion Research | Department of Energy Large Eddy Simulation (LES) Applied to Advanced Engine Combustion Research Vehicle Technologies Office Merit Review 2015: Large Eddy Simulation (LES) Applied to Advanced Engine Combustion Research Presentation given by Sandia National Laboratories at 2015 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about Large Eddy Simulation applied to advanced engine

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

    Office of Environmental Management (EM)

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

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

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

    ace007oefelein2010o.pdf More Documents & Publications Large Eddy Simulation (LES) Applied to Low-Temperature and Diesel Engine Combustion Research Large Eddy Simulation (LES)...

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

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

    Combustion Research | Department of Energy 10 DOE Vehicle Technologies and Hydrogen Programs Annual Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C. PDF icon ace007_oefelein_2010_o.pdf More Documents & Publications Large Eddy Simulation (LES) Applied to Low-Temperature and Diesel Engine Combustion Research Large Eddy Simulation (LES) Applied to Advanced Engine Combustion Research Large Eddy Simulation (LES) Applied to LTC/Diesel/Hydrogen Engine Combustion

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

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

    Combustion Research | Department of Energy Low-Temperature and Diesel Engine Combustion Research Large Eddy Simulation (LES) Applied to Low-Temperature and Diesel Engine Combustion Research 2011 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer Evaluation PDF icon ace007_oefelein_2011_o.pdf More Documents & Publications Large Eddy Simulation (LES) Applied to LTC/Diesel/Hydrogen Engine Combustion Research Large Eddy Simulation (LES) Applied

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

    Office of Environmental Management (EM)

    Combustion Research | Department of Energy Large Eddy Simulation (LES) Applied to LTC/Diesel/Hydrogen Engine Combustion Research Large Eddy Simulation (LES) Applied to LTC/Diesel/Hydrogen Engine Combustion Research 2009 DOE Hydrogen Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting, May 18-22, 2009 -- Washington D.C. PDF icon ace_07_oefelein.pdf More Documents & Publications Large Eddy Simulation (LES) Applied to Low-Temperature and Diesel Engine

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

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

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

  14. Vehicle Technologies Office Merit Review 2015: Large Eddy Simulation...

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

    Large Eddy Simulation (LES) Applied to Advanced Engine Combustion Research Vehicle Technologies Office Merit Review 2015: Large Eddy Simulation (LES) Applied to Advanced Engine...

  15. 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...

  16. Large Eddy Simulations of Combustor Liner Flows | Argonne Leadership...

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

    zone and turbine, current simulations will use wall-modeled large-eddy simulations (LES) to analyze flow in single and multi-cup combustors. An in-depth study of the detailed...

  17. 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...

  18. Large Eddy Simulation of Airfoil SelfNoise | Argonne Leadership Computing

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

    Facility Large Eddy Simulation of Airfoil SelfNoise Event Sponsor: Argonne Leadership Computing Facility Seminar Start Date: Feb 4 2016 - 10:30am Building/Room: Building 240/Room 4301 Location: Argonne National Laboratory Speaker(s): Joseph George Kocheemoolayil Speaker(s) Title: Stanford University Host: Ramesh Balakrishnan Over the past 15 years, significant strides have been made towards using large eddy simulations (LES) for predicting airfoil self-noise. However, they have largely been

  19. Large-eddy simulation of turbulent circular jet flows

    SciTech Connect (OSTI)

    Jones, S. C.; Sotiropoulos, F.; Sale, M. J.

    2002-07-01

    This report presents a numerical method for carrying out large-eddy simulations (LES) of turbulent free shear flows and an application of a method to simulate the flow generated by a nozzle discharging into a stagnant reservoir. The objective of the study was to elucidate the complex features of the instantaneous flow field to help interpret the results of recent biological experiments in which live fish were exposed to the jet shear zone. The fish-jet experiments were conducted at the Pacific Northwest National Laboratory (PNNL) under the auspices of the U.S. Department of Energy’s Advanced Hydropower Turbine Systems program. The experiments were designed to establish critical thresholds of shear and turbulence-induced loads to guide the development of innovative, fish-friendly hydropower turbine designs.

  20. Large-Eddy Simulation of Wind-Plant Aerodynamics: Preprint

    SciTech Connect (OSTI)

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

    2012-01-01

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

  1. Mesoscale and Large-Eddy Simulations for Wind Energy

    SciTech Connect (OSTI)

    Marjanovic, N

    2011-02-22

    Operational wind power forecasting, turbine micrositing, and turbine design require high-resolution simulations of atmospheric flow over complex terrain. The use of both Reynolds-Averaged Navier Stokes (RANS) and large-eddy (LES) simulations is explored for wind energy applications using the Weather Research and Forecasting (WRF) model. To adequately resolve terrain and turbulence in the atmospheric boundary layer, grid nesting is used to refine the grid from mesoscale to finer scales. This paper examines the performance of the grid nesting configuration, turbulence closures, and resolution (up to as fine as 100 m horizontal spacing) for simulations of synoptically and locally driven wind ramping events at a West Coast North American wind farm. Interestingly, little improvement is found when using higher resolution simulations or better resolved turbulence closures in comparison to observation data available for this particular site. This is true for week-long simulations as well, where finer resolution runs show only small changes in the distribution of wind speeds or turbulence intensities. It appears that the relatively simple topography of this site is adequately resolved by all model grids (even as coarse as 2.7 km) so that all resolutions are able to model the physics at similar accuracy. The accuracy of the results is shown in this paper to be more dependent on the parameterization of the land-surface characteristics such as soil moisture rather than on grid resolution.

  2. Large eddy simulation of unsteady lean stratified premixed combustion

    SciTech Connect (OSTI)

    Duwig, C.; Fureby, C.

    2007-10-15

    Premixed turbulent flame-based technologies are rapidly growing in importance, with applications to modern clean combustion devices for both power generation and aeropropulsion. However, the gain in decreasing harmful emissions might be canceled by rising combustion instabilities. Unwanted unsteady flame phenomena that might even destroy the whole device have been widely reported and are subject to intensive studies. In the present paper, we use unsteady numerical tools for simulating an unsteady and well-documented flame. Computations were performed for nonreacting, perfectly premixed and stratified premixed cases using two different numerical codes and different large-eddy-simulation-based flamelet models. Nonreacting simulations are shown to agree well with experimental data, with the LES results capturing the mean features (symmetry breaking) as well as the fluctuation level of the turbulent flow. For reacting cases, the uncertainty induced by the time-averaging technique limited the comparisons. Given an estimate of the uncertainty, the numerical results were found to reproduce well the experimental data in terms both of mean flow field and of fluctuation levels. In addition, it was found that despite relying on different assumptions/simplifications, both numerical tools lead to similar predictions, giving confidence in the results. Moreover, we studied the flame dynamics and particularly the response to a periodic pulsation. We found that above a certain excitation level, the flame dynamic changes and becomes rather insensitive to the excitation/instability amplitude. Conclusions regarding the self-growth of thermoacoustic waves were drawn. (author)

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

    SciTech Connect (OSTI)

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

    2008-09-08

    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.

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

    SciTech Connect (OSTI)

    Subramanian, V.; Domingo, P.; Vervisch, L.

    2010-03-15

    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)

  5. Applications of large-eddy simulation: Synthesis of neutral boundary layer models

    SciTech Connect (OSTI)

    Ohmstede, W.D.

    1987-12-01

    The object of this report is to describe progress made towards the application of large-eddy simulation (LES), in particular, to the study of the neutral boundary layer (NBL). The broad purpose of the study is to provide support to the LES project currently underway at LLNL. The specific purpose of this study is to lay the groundwork for the simulation of the SBL through the establishment and implementation of model criteria for the simulation of the NBL. The idealistic NBL is never observed in the atmosphere and therefore has little practical significance. However, it is of considerable theoretical interest for several reasons. The report discusses the concept of Rossby-number similarity theory as it applies to the NBL. A particular implementation of the concept is described. Then, the results from prior simulations of the NBL are summarized. Model design criteria for two versions of the Brost LES (BLES) model are discussed. The general guidelines for the development of Version 1 of the Brost model (BV1) were to implement the model with a minimum of modifications which would alter the design criteria as established by Brost. Two major modifications of BLES incorporated into BV1 pertain to the initialization/parameterization of the model and the generalization of the boundary conditions at the air/earth interface. 18 refs., 4 figs.

  6. Improving Parameterization of Entrainment Rate for Shallow Convection with Aircraft Measurements and Large-Eddy Simulation

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

    Lu, Chunsong; Liu, Yangang; Zhang, Guang J.; Wu, Xianghua; Endo, Satoshi; Cao, Le; Li, Yueqing; Guo, Xiaohao

    2016-02-01

    This work examines the relationships of entrainment rate to vertical velocity, buoyancy, and turbulent dissipation rate by applying stepwise principal component regression to observational data from shallow cumulus clouds collected during the Routine AAF [Atmospheric Radiation Measurement (ARM) Aerial Facility] Clouds with Low Optical Water Depths (CLOWD) Optical Radiative Observations (RACORO) field campaign over the ARM Southern Great Plains (SGP) site near Lamont, Oklahoma. The cumulus clouds during the RACORO campaign simulated using a large eddy simulation (LES) model are also examined with the same approach. The analysis shows that a combination of multiple variables can better represent entrainment ratemoreĀ Ā» in both the observations and LES than any single-variable fitting. Three commonly used parameterizations are also tested on the individual cloud scale. A new parameterization is therefore presented that relates entrainment rate to vertical velocity, buoyancy and dissipation rate; the effects of treating clouds as ensembles and humid shells surrounding cumulus clouds on the new parameterization are discussed. Physical mechanisms underlying the relationships of entrainment rate to vertical velocity, buoyancy and dissipation rate are also explored.Ā«Ā less

  7. Investigation of Rossby-number similarity in the neutral boundary layer using large-eddy simulation

    SciTech Connect (OSTI)

    Ohmstede, W.D.; Cederwall, R.T.; Meyers, R.E.

    1988-01-01

    One special case of particular interest, especially to theoreticians, is the steady-state, horizontally homogeneous, autobarotropic (PLB), hereafter referred to as the neutral boundary layer (NBL). The NBL is in fact a 'rare' atmospheric phenomenon, generally associated with high-wind situations. Nevertheless, there is a disproportionate interest in this problem because Rossby-number similarity theory provides a sound approach for addressing this issue. Rossby-number similarity theory has rather wide acceptance, but because of the rarity of the 'true' NBL state, there remains an inadequate experimental database for quantifying constants associated with the Rossby-number similarity concept. Although it remains a controversial issue, it has been proposed that large-eddy simulation (LES) is an alternative to physical experimentation for obtaining basic atmospherc 'data'. The objective of the study reported here is to investigate Rossby-number similarity in the NBL using LES. Previous studies have not addressed Rossby-number similarity explicitly, although they made use of it in the interpretation of their results. The intent is to calculate several sets of NBL solutions that are ambiguous relative to the their respective Rossby numbers and compare the results for similarity, or the lack of it. 14 refs., 1 fig.

  8. Practical application of large eddy simulation to film cooling flow analysis on gas turbine airfoils

    SciTech Connect (OSTI)

    Takata, T.; Takeishi, K.; Kawata, Y.; Tsuge, A.

    1999-07-01

    Large eddy simulation (LES) using body-fitted coordinates is applied to solve film cooling flow on turbine blades. The turbulent model was tuned using the experimental flow field and adiabatic film cooling effectiveness measurements for a single row of holes on a flat plate surface. The results show the interaction between the main stream boundary layer and injected film cooling air generates kidney and horseshoe shaped vortices. Comparison of the temperature distribution between experimental results and present analysis has been conducted. The non-dimensional temperature distribution at x/d = 1 is dome style and quantitatively agrees with experimental results. LES was also applied to solve film cooling on a turbine airfoil. If LES was applied to solve whole flow field domain large CPU time would make the solution impractical. LES, using body-fitted coordinates, is applied to solve the non-isotropic film cooling flow near the turbine blade. The cascade flow domain, with a pitch equal to one film cooling hole spacing, is solved using {kappa}-{epsilon} model. By using such a hybrid numerical method, CPU time is reduced and numerical accuracy is insured. The analytical results show the interaction between the flow blowing through film cooling holes and mainstream on the suction and pressure surfaces of the turbine airfoil. They also show the fundamental structure of the film cooling air flow is governed by arch internal secondary flow and horseshoe vortices which have a similar structure to film cooling air flow blowing through a cooling hole on a flat plate. In the flow field, the effect of turbulent structure on curvature (relaminarization) and flow pattern, involving the interaction between main flow and the cooling jet, are clearly shown. Film cooling effectiveness on the blade surface is predicted from the results of the thermal field calculation and is compared with the test result.

  9. Modifications to WRFs dynamical core to improve the treatment of moisture for large-eddy simulations

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

    Xiao, Heng; Endo, Satoshi; Wong, May; Skamarock, William C.; Klemp, Joseph B.; Fast, Jerome D.; Gustafson, Jr., William I.; Vogelmann, Andrew; Wang, Hailong; Liu, Yangang; et al

    2015-10-29

    Yamaguchi and Feingold (2012) note that the cloud fields in their large-eddy simulations (LESs) of marine stratocumulus using the Weather Research and Forecasting (WRF) model exhibit a strong sensitivity to time stepping choices. In this study, we reproduce and analyze this sensitivity issue using two stratocumulus cases, one marine and one continental. Results show that (1) the sensitivity is associated with spurious motions near the moisture jump between the boundary layer and the free atmosphere, and (2) these spurious motions appear to arise from neglecting small variations in water vapor mixing ratio (qv) in the pressure gradient calculation in themoreĀ Ā» acoustic sub-stepping portion of the integration procedure. We show that this issue is remedied in the WRF dynamical core by replacing the prognostic equation for the potential temperature Īø with one for the moist potential temperature Īøm=Īø(1+1.61qv), which allows consistent treatment of moisture in the calculation of pressure during the acoustic sub-steps. With this modification, the spurious motions and the sensitivity to the time stepping settings (i.e., the dynamic time step length and number of acoustic sub-steps) are eliminated in both of the example stratocumulus cases. In conclusion, this modification improves the applicability of WRF for LES applications, and possibly other models using similar dynamical core formulations, and also permits the use of longer time steps than in the original code.Ā«Ā less

  10. Modifications to WRFs dynamical core to improve the treatment of moisture for large-eddy simulations

    SciTech Connect (OSTI)

    Xiao, Heng; Endo, Satoshi; Wong, May; Skamarock, William C.; Klemp, Joseph B.; Fast, Jerome D.; Gustafson, Jr., William I.; Vogelmann, Andrew; Wang, Hailong; Liu, Yangang; Lin, Wuyin

    2015-10-29

    Yamaguchi and Feingold (2012) note that the cloud fields in their large-eddy simulations (LESs) of marine stratocumulus using the Weather Research and Forecasting (WRF) model exhibit a strong sensitivity to time stepping choices. In this study, we reproduce and analyze this sensitivity issue using two stratocumulus cases, one marine and one continental. Results show that (1) the sensitivity is associated with spurious motions near the moisture jump between the boundary layer and the free atmosphere, and (2) these spurious motions appear to arise from neglecting small variations in water vapor mixing ratio (qv) in the pressure gradient calculation in the acoustic sub-stepping portion of the integration procedure. We show that this issue is remedied in the WRF dynamical core by replacing the prognostic equation for the potential temperature Īø with one for the moist potential temperature Īøm=Īø(1+1.61qv), which allows consistent treatment of moisture in the calculation of pressure during the acoustic sub-steps. With this modification, the spurious motions and the sensitivity to the time stepping settings (i.e., the dynamic time step length and number of acoustic sub-steps) are eliminated in both of the example stratocumulus cases. In conclusion, this modification improves the applicability of WRF for LES applications, and possibly other models using similar dynamical core formulations, and also permits the use of longer time steps than in the original code.

  11. Large Eddy Simulation of Wind Turbine Wakes. Detailed Comparisons of Two Codes Focusing on Effects of Numerics and Subgrid Modeling

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

    Martinez-Tossas, Luis A.; Churchfield, Matthew J.; Meneveau, Charles

    2015-06-18

    In this work we report on results from a detailed comparative numerical study from two Large Eddy Simulation (LES) codes using the Actuator Line Model (ALM). The study focuses on prediction of wind turbine wakes and their breakdown when subject to uniform inflow. Previous studies have shown relative insensitivity to subgrid modeling in the context of a finite-volume code. The present study uses the low dissipation pseudo-spectral LES code from Johns Hopkins University (LESGO) and the second-order, finite-volume OpenFOAMcode (SOWFA) from the National Renewable Energy Laboratory. When subject to uniform inflow, the loads on the blades are found to bemoreĀ Ā» unaffected by subgrid models or numerics, as expected. The turbulence in the wake and the location of transition to a turbulent state are affected by the subgrid-scale model and the numerics.Ā«Ā less

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

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

    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 Meteorological Studies University of Oklahoma Norman, Oklahoma M. Ovtchinnikov Pacific Northwest National Laboratory A. B. Davis Los Alamos National Laboratory Los Alamos, New Mexico R. R. Cahalan National Aeronautics and Space Administration Goddard Space Flight Center Greenbelt, Maryland E. E. Takara and R. G. Ellingson

  13. Development of Quality Assessment Techniques for Large Eddy Simulation of Propulsion and Power Systems in Complex Geometries

    SciTech Connect (OSTI)

    Lacaze, Guilhem; Oefelein, Joseph

    2015-03-01

    Large-eddy-simulation (LES) is quickly becoming a method of choice for studying complex thermo-physics in a wide range of propulsion and power systems. It provides a means to study coupled turbulent combustion and flow processes in parameter spaces that are unattainable using direct-numerical-simulation (DNS), with a degree of fidelity that can be far more accurate than conventional engineering methods such as the Reynolds-averaged Navier-Stokes (RANS) approx- imation. However, development of predictive LES is complicated by the complex interdependence of different type of errors coming from numerical methods, algorithms, models and boundary con- ditions. On the other hand, control of accuracy has become a critical aspect in the development of predictive LES for design. The objective of this project is to create a framework of metrics aimed at quantifying the quality and accuracy of state-of-the-art LES in a manner that addresses the myriad of competing interdependencies. In a typical simulation cycle, only 20% of the computational time is actually usable. The rest is spent in case preparation, assessment, and validation, because of the lack of guidelines. This work increases confidence in the accuracy of a given solution while min- imizing the time obtaining the solution. The approach facilitates control of the tradeoffs between cost, accuracy, and uncertainties as a function of fidelity and methods employed. The analysis is coupled with advanced Uncertainty Quantification techniques employed to estimate confidence in model predictions and calibrate model's parameters. This work has provided positive conse- quences on the accuracy of the results delivered by LES and will soon have a broad impact on research supported both by the DOE and elsewhere.

  14. Large-eddy simulations of turbulent flow for grid-to-rod fretting in nuclear reactors

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

    Bakosi, J.; Christon, M. A.; Lowrie, R. B.; Pritchett-Sheats, L. A.; Nourgaliev, R. R.

    2013-07-12

    The grid-to-rod fretting (GTRF) problem in pressurized water reactors is a flow-induced vibration problem that results in wear and failure of the fuel rods in nuclear assemblies. In order to understand the fluid dynamics of GTRF and to build an archival database of turbulence statistics for various configurations, implicit large-eddy simulations of time-dependent single-phase turbulent flow have been performed in 3 Ɨ 3 and 5 Ɨ 5 rod bundles with a single grid spacer. To assess the computational mesh and resolution requirements, a method for quantitative assessment of unstructured meshes with no-slip walls is described. The calculations have been carriedmoreĀ Ā» out using Hydra-TH, a thermal-hydraulics code developed at Los Alamos for the Consortium for Advanced Simulation of Light water reactors, a United States Department of Energy Innovation Hub. Hydra-TH uses a second-order implicit incremental projection method to solve the singlephase incompressible Navier-Stokes equations. The simulations explicitly resolve the large scale motions of the turbulent flow field using first principles and rely on a monotonicity-preserving numerical technique to represent the unresolved scales. Each series of simulations for the 3 Ɨ 3 and 5 Ɨ 5 rod-bundle geometries is an analysis of the flow field statistics combined with a mesh-refinement study and validation with available experimental data. Our primary focus is the time history and statistics of the forces loading the fuel rods. These hydrodynamic forces are believed to be the key player resulting in rod vibration and GTRF wear, one of the leading causes for leaking nuclear fuel which costs power utilities millions of dollars in preventive measures. As a result, we demonstrate that implicit large-eddy simulation of rod-bundle flows is a viable way to calculate the excitation forces for the GTRF problem.Ā«Ā less

  15. 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

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

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

    Diagnosis of Differences Between Stratiform Clouds and Simulated by Large-Eddy Simulation and Single-Column Models S. J. Ghan and M. Ovtchinnikov Climate Physics Pacific Northwest National Laboratory Richland, Washington Introduction An adequate parameterization of cloud microphysics is essential for estimating the indirect aerosol effect in large-scale models. Such a parameterization must rely on a physically sound treatment of spatial variability that affects many microphysical processes in a

  17. Calibration and Forward Uncertainty Propagation for Large-eddy Simulations of Engineering Flows

    SciTech Connect (OSTI)

    Templeton, Jeremy Alan; Blaylock, Myra L.; Domino, Stefan P.; Hewson, John C.; Kumar, Pritvi Raj; Ling, Julia; Najm, Habib N.; Ruiz, Anthony; Safta, Cosmin; Sargsyan, Khachik; Stewart, Alessia; Wagner, Gregory

    2015-09-01

    The objective of this work is to investigate the efficacy of using calibration strategies from Uncertainty Quantification (UQ) to determine model coefficients for LES. As the target methods are for engineering LES, uncertainty from numerical aspects of the model must also be quantified. 15 The ultimate goal of this research thread is to generate a cost versus accuracy curve for LES such that the cost could be minimized given an accuracy prescribed by an engineering need. Realization of this goal would enable LES to serve as a predictive simulation tool within the engineering design process.

  18. Mean-state acceleration of cloud-resolving models and large eddy simulations

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

    Jones, C. R.; Bretherton, C. S.; Pritchard, M. S.

    2015-10-29

    In this study, large eddy simulations and cloud-resolving models (CRMs) are routinely used to simulate boundary layer and deep convective cloud processes, aid in the development of moist physical parameterization for global models, study cloud-climate feedbacks and cloud-aerosol interaction, and as the heart of superparameterized climate models. These models are computationally demanding, placing practical constraints on their use in these applications, especially for long, climate-relevant simulations. In many situations, the horizontal-mean atmospheric structure evolves slowly compared to the turnover time of the most energetic turbulent eddies. We develop a simple scheme to reduce this time scale separation to accelerate themoreĀ Ā» evolution of the mean state. Using this approach we are able to accelerate the model evolution by a factor of 2ā€“16 or more in idealized stratocumulus, shallow and deep cumulus convection without substantial loss of accuracy in simulating mean cloud statistics and their sensitivity to climate change perturbations. As a culminating test, we apply this technique to accelerate the embedded CRMs in the Superparameterized Community Atmosphere Model by a factor of 2, thereby showing that the method is robust and stable to realistic perturbations across spatial and temporal scales typical in a GCM.Ā«Ā less

  19. Large-eddy simulations of surface roughness parameter sensitivity to canopy-structure characteristics

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

    Maurer, K. D.; Bohrer, G.; Kenny, W. T.; Ivanov, V. Y.

    2015-04-30

    Surface roughness parameters, namely the roughness length and displacement height, are an integral input used to model surface fluxes. However, most models assume these parameters to be a fixed property of plant functional type and disregard the governing structural heterogeneity and dynamics. In this study, we use large-eddy simulations to explore, in silico, the effects of canopy-structure characteristics on surface roughness parameters. We performed a virtual experiment to test the sensitivity of resolved surface roughness to four axes of canopy structure: (1) leaf area index, (2) the vertical profile of leaf density, (3) canopy height, and (4) canopy gap fraction.moreĀ Ā» We found roughness parameters to be highly variable, but uncovered positive relationships between displacement height and maximum canopy height, aerodynamic canopy height and maximum canopy height and leaf area index, and eddy-penetration depth and gap fraction. We also found negative relationships between aerodynamic canopy height and gap fraction, as well as between eddy-penetration depth and maximum canopy height and leaf area index. We generalized our model results into a virtual "biometric" parameterization that relates roughness length and displacement height to canopy height, leaf area index, and gap fraction. Using a decade of wind and canopy-structure observations in a site in Michigan, we tested the effectiveness of our model-driven biometric parameterization approach in predicting the friction velocity over heterogeneous and disturbed canopies. We compared the accuracy of these predictions with the friction-velocity predictions obtained from the common simple approximation related to canopy height, the values calculated with large-eddy simulations of the explicit canopy structure as measured by airborne and ground-based lidar, two other parameterization approaches that utilize varying canopy-structure inputs, and the annual and decadal means of the surface roughness parameters at the site from meteorological observations. We found that the classical representation of constant roughness parameters (in space and time) as a fraction of canopy height performed relatively well. Nonetheless, of the approaches we tested, most of the empirical approaches that incorporate seasonal and interannual variation of roughness length and displacement height as a function of the dynamics of canopy structure produced more precise and less biased estimates for friction velocity than models with temporally invariable parameters.Ā«Ā less

  20. RACORO continental boundary layer cloud investigations. 2. Large-eddy simulations of cumulus clouds and evaluation with in-situ and ground-based observations

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

    Endo, Satoshi; Fridlind, Ann M.; Lin, Wuyin; Vogelmann, Andrew M.; Toto, Tami; Ackerman, Andrew S.; McFarquhar, Greg M.; Jackson, Robert C.; Jonsson, Haflidi H.; Liu, Yangang

    2015-06-19

    A 60-hour case study of continental boundary layer cumulus clouds is examined using two large-eddy simulation (LES) models. The case is based on observations obtained during the RACORO Campaign (Routine Atmospheric Radiation Measurement [ARM] Aerial Facility [AAF] Clouds with Low Optical Water Depths [CLOWD] Optical Radiative Observations) at the ARM Climate Research Facility's Southern Great Plains site. The LES models are driven by continuous large-scale and surface forcings, and are constrained by multi-modal and temporally varying aerosol number size distribution profiles derived from aircraft observations. We compare simulated cloud macrophysical and microphysical properties with ground-based remote sensing and aircraft observations.moreĀ Ā» The LES simulations capture the observed transitions of the evolving cumulus-topped boundary layers during the three daytime periods, and generally reproduce variations of droplet number concentration with liquid water content (LWC), corresponding to the gradient between the cloud centers and cloud edges at given heights. The observed LWC values fall within the range of simulated values; the observed droplet number concentrations are commonly higher than simulated, but differences remain on par with potential estimation errors in the aircraft measurements. Sensitivity studies examine the influences of bin microphysics versus bulk microphysics, aerosol advection, supersaturation treatment, and aerosol hygroscopicity. Simulated macrophysical cloud properties are found to be insensitive in this non-precipitating case, but microphysical properties are especially sensitive to bulk microphysics supersaturation treatment and aerosol hygroscopicity.Ā«Ā less

  1. RACORO continental boundary layer cloud investigations. 2. Large-eddy simulations of cumulus clouds and evaluation with in-situ and ground-based observations

    SciTech Connect (OSTI)

    Endo, Satoshi; Fridlind, Ann M.; Lin, Wuyin; Vogelmann, Andrew M.; Toto, Tami; Ackerman, Andrew S.; McFarquhar, Greg M.; Jackson, Robert C.; Jonsson, Haflidi H.; Liu, Yangang

    2015-06-19

    A 60-hour case study of continental boundary layer cumulus clouds is examined using two large-eddy simulation (LES) models. The case is based on observations obtained during the RACORO Campaign (Routine Atmospheric Radiation Measurement [ARM] Aerial Facility [AAF] Clouds with Low Optical Water Depths [CLOWD] Optical Radiative Observations) at the ARM Climate Research Facility's Southern Great Plains site. The LES models are driven by continuous large-scale and surface forcings, and are constrained by multi-modal and temporally varying aerosol number size distribution profiles derived from aircraft observations. We compare simulated cloud macrophysical and microphysical properties with ground-based remote sensing and aircraft observations. The LES simulations capture the observed transitions of the evolving cumulus-topped boundary layers during the three daytime periods, and generally reproduce variations of droplet number concentration with liquid water content (LWC), corresponding to the gradient between the cloud centers and cloud edges at given heights. The observed LWC values fall within the range of simulated values; the observed droplet number concentrations are commonly higher than simulated, but differences remain on par with potential estimation errors in the aircraft measurements. Sensitivity studies examine the influences of bin microphysics versus bulk microphysics, aerosol advection, supersaturation treatment, and aerosol hygroscopicity. Simulated macrophysical cloud properties are found to be insensitive in this non-precipitating case, but microphysical properties are especially sensitive to bulk microphysics supersaturation treatment and aerosol hygroscopicity.

  2. Large eddy simulations of surface roughness parameter sensitivity to canopy-structure characteristics

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

    Maurer, K. D.; Bohrer, G.; Ivanov, V. Y.

    2014-11-27

    Surface roughness parameters are at the core of every model representation of the coupling and interactions between land-surface and atmosphere, and are used in every model of surface fluxes. However, most models assume these parameters to be a fixed property of plant functional type and do not vary them in response to spatial or temporal changes to canopy structure. In part, this is due to the difficulty of reducing the complexity of canopy structure and its spatiotemporal dynamic and heterogeneity to less than a handful of parameters describing its effects of atmosphereā€“surface interactions. In this study we use large-eddy simulationsmoreĀ Ā» to explore, in silico, the effects of canopy structure characteristics on surface roughness parameters. We performed a virtual experiment to test the sensitivity of resolved surface roughness to four axes of canopy structure: (1) leaf area index, (2) the vertical profile of leaf density, (3) canopy height, and (4) canopy gap fraction. We found roughness parameters to be highly variable, but were able to find positive relationships between displacement height and maximum canopy height, aerodynamic canopy height and maximum canopy height and leaf area index, and eddy-penetration depth and gap fraction. We also found negative relationships between aerodynamic canopy height and gap fraction, and between eddy-penetration depth and maximum canopy height and leaf area index. Using a decade of wind and canopy structure observations in a site in Michigan, we tested the effectiveness of our model-resolved parameters in predicting the frictional velocity over heterogeneous and disturbed canopies. We compared it with three other semi-empirical models and with a decade of meteorological observations. We found that parameterizations with fixed representations of roughness performed relatively well. Nonetheless, some empirical approaches that incorporate seasonal and inter-annual changes to the canopy structure performed even better than models with temporally fixed parameters.Ā«Ā less

  3. Large Eddy Simulation of a Wind Turbine Airfoil at High Freestream-Flow Angle

    SciTech Connect (OSTI)

    2015-04-13

    A simulation of the airflow over a section of a wind turbine blade, run on the supercomputer Mira at the Argonne Leadership Computing Facility. Simulations like these help identify ways to make turbine blades more efficient.

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

    SciTech Connect (OSTI)

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

    2012-07-01

    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.

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

    SciTech Connect (OSTI)

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

    2014-08-01

    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 Alstomā€™s DOE project for measuring oxy-firing performance parameters in the BSF with this University of Utah project for large eddy simulation (LES) and validation/uncertainty quantification (V/UQ). The Utah work includes V/UQ with measurements in the single-burner facility where advanced strategies for O2 injection can be more easily controlled and data more easily obtained. Highlights of the work include: ā€¢ Simulations of Alstomā€™s 15 megawatt (MW) BSF, exploring the uncertainty in thermal boundary conditions. A V/UQ analysis showed consistency between experimental results and simulation results, identifying uncertainty bounds on the quantities of interest for this system (Subtask 9.1) ā€¢ A simulation study of the University of Utahā€™s oxy-fuel combustor (OFC) focused on heat flux (Subtask 9.2). A V/UQ analysis was used to show consistency between experimental and simulation results. ā€¢ 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. ā€¢ Collection of heat flux and temperature measurements in the University of Utahā€™s OFC for use is subtasks 9.2 and 9.3 (Subtask 9.4). Several replicates were carried to better assess the experimental error. Experiments were specifically designed for the generation of high-fidelity data from a turbulent oxy-coal flame for the validation of oxy-coal simulation models. Experiments were also conducted on the OFC to determine heat flux profiles using advanced strategies for O2 injection. This is important when considering retrofit of advanced O2 injection in retrofit configurations.

  6. Investigating wind turbine impacts on near-wake flow using profiling Lidar data and large-eddy simulations with an actuator disk model

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

    Mirocha, Jeffrey D.; Rajewski, Daniel A.; Marjanovic, Nikola; Lundquist, Julie K.; Kosovic, Branko; Draxl, Caroline; Churchfield, Matthew J.

    2015-08-27

    In this study, wind turbine impacts on the atmospheric flow are investigated using data from the Crop Wind Energy Experiment (CWEX-11) and large-eddy simulations (LESs) utilizing a generalized actuator disk (GAD) wind turbine model. CWEX-11 employed velocity-azimuth display (VAD) data from two Doppler lidar systems to sample vertical profiles of flow parameters across the rotor depth both upstream and in the wake of an operating 1.5 MW wind turbine. Lidar and surface observations obtained during four days of July 2011 are analyzed to characterize the turbine impacts on wind speed and flow variability, and to examine the sensitivity of thesemoreĀ Ā» changes to atmospheric stability. Significant velocity deficits (VD) are observed at the downstream location during both convective and stable portions of four diurnal cycles, with large, sustained deficits occurring during stable conditions. Variances of the streamwise velocity component, Ļƒu, likewise show large increases downstream during both stable and unstable conditions, with stable conditions supporting sustained small increases of Ļƒu , while convective conditions featured both larger magnitudes and increased variability, due to the large coherent structures in the background flow. Two representative case studies, one stable and one convective, are simulated using LES with a GAD model at 6 m resolution to evaluate the compatibility of the simulation framework with validation using vertically profiling lidar data in the near wake region. Virtual lidars were employed to sample the simulated flow field in a manner consistent with the VAD technique. Simulations reasonably reproduced aggregated wake VD characteristics, albeit with smaller magnitudes than observed, while Ļƒu values in the wake are more significantly underestimated. The results illuminate the limitations of using a GAD in combination with coarse model resolution in the simulation of near wake physics, and validation thereof using VAD data.Ā«Ā less

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

    SciTech Connect (OSTI)

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

    2014-06-01

    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.

  8. Intercomparison of Large-eddy Simulations of Arctic Mixed-phase Clouds: Importance of Ice Size Distribution Assumptions

    SciTech Connect (OSTI)

    Ovchinnikov, Mikhail; Ackerman, Andrew; Avramov, Alex; Cheng, Anning; Fan, Jiwen; Fridlind, Ann; Ghan, Steven J.; Harrington, Jerry Y.; Hoose, Corinna; Korolev, Alexei; McFarquhar, Greg; Morrison, H.; Paukert, Marco; Savre, Julien; Shipway, Ben; Shupe, Matthew D.; Solomon, Amy; Sulia, Kara

    2014-03-14

    Large-eddy simulations of mixed-phase Arctic clouds by 11 different models are analyzed with the goal of improving understanding and model representation of processes controlling the evolution of these clouds. In a case based on observations from the Indirect and Semi-Direct Aerosol Campaign (ISDAC), it is found that ice number concentration, Ni, exerts significant influence on the cloud structure. Increasing Ni leads to a substantial reduction in liquid water path (LWP) and potential cloud dissipation, in agreement with earlier studies. By comparing simulations with the same microphysics coupled to different dynamical cores as well as the same dynamics coupled to different microphysics schemes, it is found that the ice water path (IWP) is mainly controlled by ice microphysics, while the inter-model differences in LWP are largely driven by physics and numerics of the dynamical cores. In contrast to previous intercomparisons, all models here use the same ice particle properties (i.e., mass-size, mass-fall speed, and mass-capacitance relationships) and a common radiation parameterization. The constrained setup exposes the importance of ice particle size distributions (PSD) in influencing cloud evolution. A clear separation in LWP and IWP predicted by models with bin and bulk microphysical treatments is documented and attributed primarily to the assumed shape of ice PSD used in bulk schemes. Compared to the bin schemes that explicitly predict the PSD, schemes assuming exponential ice PSD underestimate ice growth by vapor deposition and overestimate mass-weighted fall speed leading to an underprediction of IWP by a factor of two in the considered case.

  9. ARM - LES ARM Symbiotic Simulation and Observation Workflow

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

    ThemesLES ARM Symbiotic Simulation and Observation Workflow LASSO Information LASSO Home LASSO Backgrounder Pilot Phase Begins for Routine Large-Eddy Simulations Pilot Project Timeline Presentations Science LASSO Implementation Strategy Related Information ARM Decadal Vision Archive of LASSO Information e-mail list LASSO Collaboration Letter Contacts William Gustafson, Lead Principal Investigator Andrew Vogelmann, Co-Principal Investigator Hanna Goss, Media Contact LES ARM Symbiotic Simulation

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

    SciTech Connect (OSTI)

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

    2013-10-01

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

  11. Comparison of the Dynamic Wake Meandering Model, Large-Eddy Simulation, and Field Data at the Egmond aan Zee Offshore Wind Plant: Preprint

    SciTech Connect (OSTI)

    Churchfield, M. J.; Moriarty, P. J.; Hao, Y.; Lackner, M. A.; Barthelmie, R.; Lundquist, J.; Oxley, G. S.

    2014-12-01

    The focus of this work is the comparison of the dynamic wake meandering model and large-eddy simulation with field data from the Egmond aan Zee offshore wind plant composed of 36 3-MW turbines. The field data includes meteorological mast measurements, SCADA information from all turbines, and strain-gauge data from two turbines. The dynamic wake meandering model and large-eddy simulation are means of computing unsteady wind plant aerodynamics, including the important unsteady meandering of wakes as they convect downstream and interact with other turbines and wakes. Both of these models are coupled to a turbine model such that power and mechanical loads of each turbine in the wind plant are computed. We are interested in how accurately different types of waking (e.g., direct versus partial waking), can be modeled, and how background turbulence level affects these loads. We show that both the dynamic wake meandering model and large-eddy simulation appear to underpredict power and overpredict fatigue loads because of wake effects, but it is unclear that they are really in error. This discrepancy may be caused by wind-direction uncertainty in the field data, which tends to make wake effects appear less pronounced.

  12. Implementation and assessment of turbine wake models in the Weather Research and Forecasting model for both mesoscale and large-eddy simulation

    SciTech Connect (OSTI)

    Singer, M; Mirocha, J; Lundquist, J; Cleve, J

    2010-03-03

    Flow dynamics in large wind projects are influenced by the turbines located within. The turbine wakes, regions characterized by lower wind speeds and higher levels of turbulence than the surrounding free stream flow, can extend several rotor diameters downstream, and may meander and widen with increasing distance from the turbine. Turbine wakes can also reduce the power generated by downstream turbines and accelerate fatigue and damage to turbine components. An improved understanding of wake formation and transport within wind parks is essential for maximizing power output and increasing turbine lifespan. Moreover, the influence of wakes from large wind projects on neighboring wind farms, agricultural activities, and local climate are all areas of concern that can likewise be addressed by wake modeling. This work describes the formulation and application of an actuator disk model for studying flow dynamics of both individual turbines and arrays of turbines within wind projects. The actuator disk model is implemented in the Weather Research and Forecasting (WRF) model, which is an open-source atmospheric simulation code applicable to a wide range of scales, from mesoscale to large-eddy simulation. Preliminary results demonstrate the applicability of the actuator disk model within WRF to a moderately high-resolution large-eddy simulation study of a small array of turbines.

  13. Simulation of Post-Frontal Boundary Layers Observed During the...

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

    University of North Dakota Grand Forks, North Dakota Introduction Large-eddy simulation (LES) models have been widely employed in the study of radiatively forced cloud topped...

  14. LES Modeling for IC Engines | Department of Energy

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

    LES Modeling for IC Engines LES Modeling for IC Engines Large eddy simulation offers better accuracy and sensitivity to study cyclic variability, mode transition and mixing effects in engine design and operation PDF icon deer12_rutland.pdf More Documents & Publications Large Eddy Simulation (LES) Applied to Advanced Engine Combustion Research Optimization of Advanced Diesel Engine Combustion Strategies A Workshop to Identify Research Needs and Impacts in Predictive Simulation for Internal

  15. RACORO continental boundary layer cloud investigations. 2. Large-eddy

    Office of Scientific and Technical Information (OSTI)

    simulations of cumulus clouds and evaluation with in-situ and ground-based observations (Journal Article) | SciTech Connect 2. Large-eddy simulations of cumulus clouds and evaluation with in-situ and ground-based observations Citation Details In-Document Search This content will become publicly available on June 19, 2016 Title: RACORO continental boundary layer cloud investigations. 2. Large-eddy simulations of cumulus clouds and evaluation with in-situ and ground-based observations A

  16. LES ARM Symbiotic Simulation and Observation (LASSO) Implementation Strategy

    SciTech Connect (OSTI)

    Gustafson Jr., WI; Vogelmann, AM

    2015-09-01

    This document illustrates the design of the Large-Eddy Simulation (LES) ARM Symbiotic Simulation and Observation (LASSO) workflow to provide a routine, high-resolution modeling capability to augment the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facilityā€™s high-density observations. LASSO will create a powerful new capability for furthering ARMā€™s mission to advance understanding of cloud, radiation, aerosol, and land-surface processes. The combined observational and modeling elements will enable a new level of scientific inquiry by connecting processes and context to observations and providing needed statistics for details that cannot be measured. The result will be improved process understanding that facilitates concomitant improvements in climate model parameterizations. The initial LASSO implementation will be for ARMā€™s Southern Great Plains site in Oklahoma and will focus on shallow convection, which is poorly simulated by climate models due in part to cloudsā€™ typically small spatial scale compared to model grid spacing, and because the convection involves complicated interactions of microphysical and boundary layer processes.

  17. A filtered tabulated chemistry model for LES of premixed combustion

    SciTech Connect (OSTI)

    Fiorina, B.; Auzillon, P.; Darabiha, N.; Gicquel, O.; Veynante, D. [EM2C - CNRS, Ecole Centrale Paris, 92295 Chatenay Malabry (France); Vicquelin, R. [EM2C - CNRS, Ecole Centrale Paris, 92295 Chatenay Malabry (France); GDF SUEZ, Pole CHENE, Centre de Recherche et d'Innovation Gaz et Energies Nouvelles, 93211 Saint-Denis la Plaine (France)

    2010-03-15

    A new modeling strategy called F-TACLES (Filtered Tabulated Chemistry for Large Eddy Simulation) is developed to introduce tabulated chemistry methods in Large Eddy Simulation (LES) of turbulent premixed combustion. The objective is to recover the correct laminar flame propagation speed of the filtered flame front when subgrid scale turbulence vanishes as LES should tend toward Direct Numerical Simulation (DNS). The filtered flame structure is mapped using 1-D filtered laminar premixed flames. Closure of the filtered progress variable and the energy balance equations are carefully addressed in a fully compressible formulation. The methodology is first applied to 1-D filtered laminar flames, showing the ability of the model to recover the laminar flame speed and the correct chemical structure when the flame wrinkling is completely resolved. The model is then extended to turbulent combustion regimes by including subgrid scale wrinkling effects in the flame front propagation. Finally, preliminary tests of LES in a 3-D turbulent premixed flame are performed. (author)

  18. Simulating atmosphere flow for wind energy applications with WRF-LES

    SciTech Connect (OSTI)

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

    2008-01-14

    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.

  19. Adaptive LES Methodology for Turbulent Flow Simulations

    SciTech Connect (OSTI)

    Oleg V. Vasilyev

    2008-06-12

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

  20. Simulating flame lift-off characteristics of diesel and biodiesel fuels using detailed chemical-kinetic mechanisms and LES turbulence model.

    SciTech Connect (OSTI)

    Som, S; Longman, D. E.; Luo, Z; Plomer, M; Lu, T; Senecal, P.K.; Pomraning, E

    2012-01-01

    Combustion in direct-injection diesel engines occurs in a lifted, turbulent diffusion flame mode. Numerous studies indicate that the combustion and emissions in such engines are strongly influenced by the lifted flame characteristics, which are in turn determined by fuel and air mixing in the upstream region of the lifted flame, and consequently by the liquid breakup and spray development processes. From a numerical standpoint, these spray combustion processes depend heavily on the choice of underlying spray, combustion, and turbulence models. The present numerical study investigates the influence of different chemical kinetic mechanisms for diesel and biodiesel fuels, as well as Reynolds-averaged Navier-Stokes (RANS) and large eddy simulation (LES) turbulence models on predicting flame lift-off lengths (LOLs) and ignition delays. Specifically, two chemical kinetic mechanisms for n-heptane (NHPT) and three for biodiesel surrogates are investigated. In addition, the RNG k-{epsilon} (RANS) model is compared to the Smagorinsky based LES turbulence model. Using adaptive grid resolution, minimum grid sizes of 250 {micro}m and 125 {micro}m were obtained for the RANS and LES cases respectively. Validations of these models were performed against experimental data from Sandia National Laboratories in a constant volume combustion chamber. Ignition delay and flame lift-off validations were performed at different ambient temperature conditions. The LES model predicts lower ignition delays and qualitatively better flame structures compared to the RNG k-{epsilon} model. The use of realistic chemistry and a ternary surrogate mixture, which consists of methyl decanoate, methyl 9-decenoate, and NHPT, results in better predicted LOLs and ignition delays. For diesel fuel though, only marginal improvements are observed by using larger size mechanisms. However, these improved predictions come at a significant increase in computational cost.

  1. Combustion Energy Frontier Research Center Post-Doctoral Position in Advanced Combustion Simulations

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

    Energy Frontier Research Center (CEFRC) seeks outstanding applicants for the position of post-doctoral research associate to perform research at Cornell University and Sandia National Laboratories on advanced simulations of turbulent combustion. This position is as a Combustion Energy Research Fellow, as described at http://pcl.princeton.edu/efrc/fellow_Flyer.html . The project involves two simulation methodologies: direct numerical simulation (DNS); and large-eddy simulation (LES) using the

  2. Combustion Energy Frontier Research Center Post-Doctoral Position in Advanced Combustion Simulations

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

    EFRC seeks outstanding applicants for the position of post-doctoral research associate to perform research at Cornell University and Sandia National Laboratories on advanced simulations of turbulent combustion. The project involves two simulation methodologies: direct numerical simulation (DNS); and large-eddy simulation (LES) using the filtered density function (FDF) approach. DNS involves minimal modeling, but is restricted (by computational capabilities) to simple geometries and a moderate

  3. LES SOFTWARE FOR THE DESIGN OF LOW EMISSION COMBUSTION SYSTEMS FOR VISION 21 PLANTS

    SciTech Connect (OSTI)

    Clifford Smith

    2003-09-01

    Application and testing of the new combustion Large Eddy Simulation (LES) code for the design of advanced gaseous combustion systems is described in this 12th quarterly report. In this quarter, continued validation and testing of the combustion LES code was performed for the DOE-SimVal combustor. Also, beta testing by six consortium members was performed for various burner and combustor configurations. A list of suggested code improvements by the beta testers was itemized. Work will continue in FY04. A conditional modification to the contract will be granted. The additional work will focus on modeling/analyzing the SimVal experiments.

  4. Large Eddy Simulation of Stable Boundary Layer Turbulent Processes in Complex Terrain

    SciTech Connect (OSTI)

    Eric D. Skyllingstad

    2005-01-26

    Research was performed using a turbulence boundary layer model to study the behavior of cold, dense flows in regions of complex terrain. Results show that flows develop a balance between turbulent entrainment of warm ambient air and dense, cold air created by surface cooling. Flow depth and strength is a function of downslope distance, slope angle and angle changes, and the ambient air temperature.

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

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

    Department of Energy 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

  6. LES SOFTWARE FOR THE DESIGN OF LOW EMISSION COMBUSTION SYSTEMS FOR VISION 21 PLANTS

    SciTech Connect (OSTI)

    Steve Cannon; Baifang Zuo; Virgil Adumitroaie; Keith McDaniel; Cliff Smith

    2002-01-01

    Further development of a combustion Large Eddy Simulation (LES) code for the design of advanced gaseous combustion systems is described in this fifth quarterly report. CFD Research Corporation (CFDRC) is developing the LES module within the parallel, unstructured solver included in the commercial CFD-ACE+ software. In this quarter, in-situ adaptive tabulation (ISAT) for efficient chemical rate storage and retrieval was further tested in the LES code. The use of multiple trees and periodic tree dumping was investigated. Implementation of the Linear Eddy Model (LEM) for subgrid chemistry was finished for serial applications. Validation of the model on a backstep reacting case was performed. Initial calculations of the SimVal experiment were performed for various barrel lengths, equivalence ratio, combustor shapes, and turbulence models. The effects of these variables on combustion instability was studied. Georgia Tech continues the effort to parameterize the LEM over composition space so that a neural net can be used efficiently in the combustion LES code. Next quarter, the 2nd consortium meeting will be held at CFDRC. LES software development and testing will continue. Alpha testing of the code will be performed on cases of interest to the industrial consortium. Optimization of subgrid models will be pursued, particularly with the ISAT approach. Also next quarter, the demonstration of the neural net approach, for chemical kinetics speed-up in CFD-ACE+, should be accomplished.

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

    SciTech Connect (OSTI)

    Not Available

    2012-04-01

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

  8. LES SOFTWARE FOR THE DESIGN OF LOW EMISSION COMBUSTION SYSTEMS FOR VISION 21 PLANTS

    SciTech Connect (OSTI)

    Steven Cannon; Clifford Smith

    2003-04-01

    Application and testing of the new combustion Large Eddy Simulation (LES) code for the design of advanced gaseous combustion systems is described in this 10th quarterly report. CFD Research Corporation has developed the LES module within the parallel, unstructured solver included in the commercial CFD-ACE+ software. In this quarter, validation and testing of the combustion LES code was performed for the DOE-Simval combustor. Also, Beta testing by consortium members was performed for various burner and combustor configurations. In the two quarters ahead, CFDRC will validate the code on the new DOE SimVal experiments. Experimental data from DOE should be available in June 2003, though LES calculations are currently being performed. This will ensure a truly predictive test of the software. CFDRC will also provide help to the consortium members on running their cases, and incorporate improvements to the software suggested by the beta testers. The beta testers will compare their predictions with experimental measurements and other numerical calculations. At the end of this project (October, 2003), a final released version of the software will be available for licensing to the general public.

  9. A Study of Strain Rate Effects for Turbulent Premixed Flames with Application to LES of a Gas Turbine Combustor Model

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

    Kemenov, Konstantin A.; Calhoon, William H.

    2015-03-24

    Large-scale strain rate field, a resolved quantity which is easily computable in large-eddy simulations (LES), could have profound effects on the premixed flame properties by altering the turbulent flame speed and inducing local extinction. The role of the resolved strain rate has been investigated in a posterior LES study of GE lean premixed dry low NOx emissions LM6000 gas turbine combustor model. A novel approach which is based on the coupling of the lineareddy model with a one-dimensional counter-flow solver has been applied to obtain the parameterizations of the resolved premixed flame properties in terms of the reactive progress variable,moreĀ Ā» the local strain rate measure, and local Reynolds and Karlovitz numbers. The strain rate effects have been analyzed by comparing LES statistics for several models of the turbulent flame speed, i.e, with and without accounting for the local strain rate effects, with available experimental data. The sensitivity of the simulation results to the inflow velocity conditions as well as the grid resolution have been also studied. Overall, the results suggest the necessity to represent the strain rate effects accurately in order to improve LES modeling of the turbulent flame speed.Ā«Ā less

  10. A Study of Strain Rate Effects for Turbulent Premixed Flames with Application to LES of a Gas Turbine Combustor Model

    SciTech Connect (OSTI)

    Kemenov, Konstantin A.; Calhoon, William H.

    2015-03-24

    Large-scale strain rate field, a resolved quantity which is easily computable in large-eddy simulations (LES), could have profound effects on the premixed flame properties by altering the turbulent flame speed and inducing local extinction. The role of the resolved strain rate has been investigated in a posterior LES study of GE lean premixed dry low NOx emissions LM6000 gas turbine combustor model. A novel approach which is based on the coupling of the lineareddy model with a one-dimensional counter-flow solver has been applied to obtain the parameterizations of the resolved premixed flame properties in terms of the reactive progress variable, the local strain rate measure, and local Reynolds and Karlovitz numbers. The strain rate effects have been analyzed by comparing LES statistics for several models of the turbulent flame speed, i.e, with and without accounting for the local strain rate effects, with available experimental data. The sensitivity of the simulation results to the inflow velocity conditions as well as the grid resolution have been also studied. Overall, the results suggest the necessity to represent the strain rate effects accurately in order to improve LES modeling of the turbulent flame speed.

  11. LES SOFTWARE FOR THE DESIGN OF LOW EMISSION COMBUSTION SYSTEMS FOR VISION 21 PLANTS

    SciTech Connect (OSTI)

    Steven Cannon; Baifang Zuo; Virgil Adumitroaie; Keith McDaniel; Clifford Smith

    2002-04-30

    Further development of a combustion Large Eddy Simulation (LES) code for the design of advanced gaseous combustion systems is described in this sixth quarterly report. CFD Research Corporation (CFDRC) is developing the LES module within the parallel, unstructured solver included in the commercial CFD-ACE+ software. In this quarter, in-situ adaptive tabulation (ISAT) for efficient chemical rate storage and retrieval was implemented and tested within the Linear Eddy Model (LEM). ISAT type 3 is being tested so that extrapolation can be performed and further improve the retrieval rate. Further testing of the LEM for subgrid chemistry was performed for parallel applications and for multi-step chemistry. Validation of the software on backstep and bluff-body reacting cases were performed. Initial calculations of the SimVal experiment at Georgia Tech using their LES code were performed. Georgia Tech continues the effort to parameterize the LEM over composition space so that a neural net can be used efficiently in the combustion LES code. A new and improved Artificial Neural Network (ANN), with log-transformed output, for the 1-step chemistry was implemented in CFDRC's LES code and gave reasonable results. This quarter, the 2nd consortium meeting was held at CFDRC. Next quarter, LES software development and testing will continue. Alpha testing of the code will continue to be performed on cases of interest to the industrial consortium. Optimization of subgrid models will be pursued, particularly with the ISAT approach. Also next quarter, the demonstration of the neural net approach, for multi-step chemical kinetics speed-up in CFD-ACE+, will be accomplished.

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

    SciTech Connect (OSTI)

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

    2010-02-22

    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.

  13. Sandia Energy - Computational Fluid Dynamics Simulations Provide...

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

    from a VWiS large-eddy simulation. One of the primary roles of Sandia's Scaled Wind Farm Technology (SWiFT) facility will be to conduct detailed experiments on turbine wakes and...

  14. LES SOFTWARE FOR THE DESIGN OF LOW EMISSION COMBUSTION SYSTEMS FOR VISION 21 PLANTS

    SciTech Connect (OSTI)

    Steve Cannon; Virgil Adumitroaie; Keith McDaniel; Cliff Smith

    2001-05-01

    Further development of a Large Eddy Simulation (LES) code for the design of advanced gaseous combustion systems is described in this second quarterly report. CFD Research Corporation (CFDRC) is developing the LES module within the parallel, unstructured solver included in the commercial CFD-ACE+ software. CFDRC has implemented and tested Smagorinsky and localized dynamic subgrid turbulence models on a 2.1 million cell DOE-NETL combustor case and a 400,000 cell nonreacting backstep case. Both cases showed good agreement between predicted and experimental results. The large DOE-NETL case results provided better agreement with the measured oscillation frequency than previous attempts because massive parallel computing (on a cluster of 24 pcs) allowed the entire computational domain, including the swirler vanes and fuel spokes, to be modeled. Subgrid chemistry models, including the conditional moment closure (CMC) and linear eddy model (LEM), are being tested and implemented. Reduced chemical mechanisms have been developed for emissions, ignition delay, extinction, and flame propagation using a computer automated reduction method (CARM). A 19-species natural gas mechanism, based on GRI2.11 and Miller-NO{sub x}, was shown to predict rich NO{sub x} emissions better than any previously published mechanisms. The ability to handle this mechanism in CFD-ACE+ was demonstrated by implementing operator splitting and a stiff ODE solver (DVODE). Efficient tabulation methods, including in situ adaptation and artificial neural nets, are being studied and will be implemented in the LES code. The LES combustion code development and testing is on schedule. Next quarter, initial results (including the DOE-NETL unstable combustor) with the CMC and LEM subgrid chemistry models will be completed and summarized.

  15. Sibendu Som | Argonne National Laboratory

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

    of Nozzle Orifice Geometry Fuel Spray Modeling High-Fidelity Large Eddy Simulations (LES) Multi-Dimensional Modeling Simulation Approaches for Drop-in Biofuels Virtual Engine...

  16. ARM - Publications: Science Team Meeting Documents: Variance...

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

    in shallow cumulus topped mixed layers is studied using large-eddy simulation (LES) results. The simulations are based on a range of different shallow cumulus cases,...

  17. Research Highlight

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

    the ocean surface. The behavior of the GCCN parameterization in a large-eddy simulation (LES) framework is consistent with simulations employing explicit, size-resolving...

  18. ARM - Publications: Science Team Meeting Documents

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

    this study, a marine stratocumulus cloud was simulated by using a large eddy simulation (LES) model and a detailed microphysical bin model. Including infrared cooling as well as...

  19. ARM - Facility News Article

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

    priorities for enhancing the outcomes of running routine large-eddy simulation (LES) simulations as outlined in the report: Carry out a pilot study in which the issues...

  20. boehm-98.pdf

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

    a cirrus cloud model. Model The cirrus model is a two-dimensional large-eddy simulation (LES) model with coupled dynamics, radiative transfer, and microphysics modules. The...

  1. Sticky Thermals: Evidence for a Dominant Balance Between

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

    by studying thousands of cloud thermals in a high- resolution large-eddy simulation (LES) of deep convection. Schematically, the acceleration of a cloud thermal can be written...

  2. Modeling Precipitating Cumulus Congestus Observed by the ARM...

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

    (GCMs). Typically, results from cloud-resolving models (CRMs) or large-eddy simulation (LES) models serve as benchmarks for developing and tuning single-column models (SCMs),...

  3. BALTEX BRIDGE cloud liquid water network project: CLIWA-NET

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

    cloud types 432008 ARM-08 (Simplified) Working Strategy of GCSS Large Eddy Simulation (LES) Models Cloud Resolving Models (CRM) Single Column Model Versions of Climate Models...

  4. ARM - Publications: Science Team Meeting Documents

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

    University (b) Twelfth Atmospheric Radiation Measurement (ARM) Science Team Meeting LES (large eddy simulation) models can explicitly resolve large turbulent eddies, which...

  5. Research Highlight

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

    convection using a new technique for large-eddy simulations (LES) called "Eulerian direct measurement". These results were confirmed by Dawe and Austin (2011) using a related...

  6. LES SOFTWARE FOR THE DESIGN OF LOW EMISSION COMBUSTION SYSTEMS FOR VISION 21 PLANTS

    SciTech Connect (OSTI)

    Clifford E. Smith; Steven M. Cannon; Virgil Adumitroaie; David L. Black; Karl V. Meredith

    2005-01-01

    In this project, an advanced computational software tool was developed for the design of low emission combustion systems required for Vision 21 clean energy plants. Vision 21 combustion systems, such as combustors for gas turbines, combustors for indirect fired cycles, furnaces and sequestrian-ready combustion systems, will require innovative low emission designs and low development costs if Vision 21 goals are to be realized. The simulation tool will greatly reduce the number of experimental tests; this is especially desirable for gas turbine combustor design since the cost of the high pressure testing is extremely costly. In addition, the software will stimulate new ideas, will provide the capability of assessing and adapting low-emission combustors to alternate fuels, and will greatly reduce the development time cycle of combustion systems. The revolutionary combustion simulation software is able to accurately simulate the highly transient nature of gaseous-fueled (e.g. natural gas, low BTU syngas, hydrogen, biogas etc.) turbulent combustion and assess innovative concepts needed for Vision 21 plants. In addition, the software is capable of analyzing liquid-fueled combustion systems since that capability was developed under a concurrent Air Force Small Business Innovative Research (SBIR) program. The complex physics of the reacting flow field are captured using 3D Large Eddy Simulation (LES) methods, in which large scale transient motion is resolved by time-accurate numerics, while the small scale motion is modeled using advanced subgrid turbulence and chemistry closures. In this way, LES combustion simulations can model many physical aspects that, until now, were impossible to predict with 3D steady-state Reynolds Averaged Navier-Stokes (RANS) analysis, i.e. very low NOx emissions, combustion instability (coupling of unsteady heat and acoustics), lean blowout, flashback, autoignition, etc. LES methods are becoming more and more practical by linking together tens to hundreds of PCs and performing parallel computations with fine grids (millions of cells). Such simulations, performed in a few weeks or less, provide a very cost-effective complement to experimental testing. In 5 years, these same calculations can be performed in 24 hours or less due to the expected increase of computing power and improved numerical techniques. This project was a four-year program. During the first year, the project included the development and implementation of improved chemistry (reduced GRI mechanism), subgrid turbulence (localized dynamic), and subgrid combustion-turbulence interaction (Linear Eddy) models into the CFD-ACE+ code. University expertise (Georgia Tech and University of California, Berkeley) was utilized to help develop and implement these advanced submodels into the unstructured, parallel CFD flow solver, CFD-ACE+. Efficient numerical algorithms that rely on in situ look-up tables or artificial neural networks were implemented for chemistry calculations. In the second year, the combustion LES software was evaluated and validated using experimental data from lab-scale and industrial test configurations. This code testing (i.e., alpha testing) was performed by CFD Research Corporation's engineers. During the third year, six industrial and academic partners used the combustion LES code and exercised it on problems of their choice (i.e., beta testing). Final feedback and optimizations were then implemented into the final release (licensed) version of the combustion LES software to the general public. An additional one-year task was added for the fourth year of this program entitled, ''LES Simulations of SIMVAL Results''. For this task, CFDRC performed LES calculations of selected DoE SIMVAL cases, and compared predictions with measurements from NETL. In addition to comparisons with NOx and CO exit measurements, comparisons were made to measured pressure oscillations. Potential areas of improvement for combustion and turbulence models were identified. In conclusion, this program advanced the state-of-the-art in combustion LES an

  7. New Aerodynamics Simulations Provide Better Understanding of Wind Plant Underperformance and Loading (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2011-02-01

    Researchers at the National Renewable Energy Laboratory (NREL) develop a high-fidelity large-eddy simulation model designed to predict the performance of large wind plants with a higher degree of accuracy than current models.

  8. 2011_INCITE_Fact_Sheets.pdf | Department of Energy

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

    1_INCITE_Fact_Sheets.pdf 2011_INCITE_Fact_Sheets.pdf PDF icon 2011_INCITE_Fact_Sheets.pdf More Documents & Publications Advance Patent Waiver W(A)2006-028 Large Eddy Simulation (LES) Applied to LTC/Diesel/Hydrogen Engine Combustion Research Vehicle Technologies Office Merit Review 2015: Large Eddy Simulation (LES) Applied to Advanced Engine Combustion Research

  9. ARM - Publications: Science Team Meeting Documents

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

    as that of Large Eddy Simulation models, they provide a means for explicitly evaluating LES (LEO for LES). Further the radar observations can be used to examine the subgrid scale...

  10. 1

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

    (3D) broken field of marine clouds is simulated by using large-eddy simulation (LES) model. The obtained 3D cloud field is considered as a real 3D cloud field. Second, we...

  11. CNS 2008 Template

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

    andoua@westinghouse.com Abstract The purpose of the present study is to evaluate the feasibility of use of CFD Large Eddy Simulation (LES) modeling techniques in CD-adapco CFD code...

  12. OFFICE OF BIOLOGICAL AND ENVIRONMENTAL RESEARCH Climate and Environmen...

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

    Shallow convection systems over the SGP are amenable to large-eddy simulation (LES) with domains on the order of a few tens of kilometers. Their resolution is reasonably...

  13. Research Highlight

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

    by studying thousands of cloud thermals in a high-resolution large-eddy simulation (LES) of deep convection. Schematically, the acceleration of a cloud thermal can be written...

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

    SciTech Connect (OSTI)

    Sanjiva Lele

    2012-10-01

    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.

  15. LES SOFTWARE FOR THE DESIGN OF LOW EMISSION COMBUSTION SYSTEMS FOR VISION 21 PLANTS

    SciTech Connect (OSTI)

    Cannon, Steven M.; Adumitroaie, Virgil; McDaniel, Keith S.; Smith, Clifford E.

    2001-11-06

    In this project, an advanced computational software tool will be developed for the design of low emission combustion systems required for Vision 21 clean energy plants. This computational tool will utilize Large Eddy Simulation (LES) methods to predict the highly transient nature of turbulent combustion. The time-accurate software will capture large scale transient motion, while the small scale motion will be modeled using advanced subgrid turbulence and chemistry closures. This three-year project is composed of: Year 1--model development/implementation, Year 2--software alpha validation, and Year 3--technology transfer of software to industry including beta testing. In this first year of the project, subgrid models for turbulence and combustion are being developed through university research (Suresh Menon-Georgia Tech and J.-Y. Chen- UC Berkeley) and implemented into a leading combustion CFD code, CFD-ACE+. The commercially available CFDACE+ software utilizes unstructured , parallel architecture and 2nd-order spatial and temporal numerics. To date, the localized dynamic turbulence model and reduced chemistry models (up to 19 species) for natural gas, propane, hydrogen, syngas, and methanol have been incorporated. The Linear Eddy Model (LEM) for subgrid combustion-turbulence interaction has been developed and implementation into CFD-ACE+ has started. Ways of reducing run-time for complex stiff reactions is being studied, including the use of in situ tabulation and neural nets. Initial validation cases have been performed. CFDRC has also completed the integration of a 64 PC cluster to get highly scalable computing power needed to perform the LES calculations ({approx} 2 million cells) in several days. During the second year, further testing and validation of the LES software will be performed. Researchers at DOE-NETL are working with CFDRC to provide well-characterized high-pressure test data for model validation purposes. To insure practical, usable software is developed, a consortium of gas turbine and industrial burner manufacturers has been established to guide and direct the software development/validation effort. The consortium members include Siemens- Westinghouse, GE Power Systems, Pratt & Whitney, Rolls-Royce, Honeywell, Solar, Coen, McDermott, Vapor Power, Woodward FST, Parker Hannifin, John Zink, RamGen Power, Virginia Tech, DOE-NETL, Air Force Research Laboratory, DOE-ANL, and NASA GRC. Annual consortium meetings are being held in Huntsville, with the 2nd meeting scheduled for January 31-February 1, 2002. 2 Benefits of the program will include the ability to assess complex combustion challenges such as combustion instability, lean blowout, flashback, emissions and the effect of fuel type on performance. The software will greatly reduce development costs and the time cycle of combustor development. And perhaps the greatest benefit will be that the software will stimulate new, creative ideas to solve the combustion challenges of the Vision 21 plant.

  16. Bluff Body Flow Simulation Using a Vortex Element Method

    SciTech Connect (OSTI)

    Anthony Leonard; Phillippe Chatelain; Michael Rebel

    2004-09-30

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

  17. Microsoft PowerPoint - wrf_les_2007_zhu.ppt [Compatibility Mode]

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

    LES Testbed Prototype: ARM LES Testbed Prototype: Multi-Scale WRF Simulations of Boundary Layer Clouds Ping Zhu Florida International University Pavlos Kollias Brookhaven National Laboratory Bruce Albrecht University of Miami What is ARM-LES-Testbed ? It is structured to provide a framework for effectively organizing and using the extensive data generated by the ARM radars and other ARM observing systems for boundary layer cloud studies and for evaluating high resolution simulations. GCM/ PAR

  18. LASSO: Tying ARM Data and LES Modeling Together to Improve Climate Science

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

    LASSO: Tying ARM Data and LES Modeling Together to Improve Climate Science New Routine Modeling The pilot modeling project, called LASSO-the LES ARM Symbiotic Simulation and Observation workflow-is laying the groundwork to produce routine LES modeling at the ARM Southern Great Plains (SGP) megasite starting in 2017. The initial LASSO implementation will target shallow clouds and will later expand to other phenomena and ARM sites. A key to creating the next-generation Atmospheric Radiation

  19. Landfill Energy Systems LES | Open Energy Information

    Open Energy Info (EERE)

    Energy Systems LES Jump to: navigation, search Name: Landfill Energy Systems (LES) Place: Michigan Zip: 48393 Product: Landfill gas to energy systems project developer, gas...

  20. LES Modeling of High Resolution Satellite Cloud Spatial and Thermal

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

    Structure at ARM-SGP site: How well can we Simulate Clouds from Space? LES Modeling of High Resolution Satellite Cloud Spatial and Thermal Structure at ARM-SGP site: How well can we Simulate Clouds from Space? Dubey, Manvendra DOE/Los Alamos National Laboratory Chylek, Petr DOE/Los Alamos National Laboratory Reisner, Jon Los Alamos National Laboratory Porch, William Los Alamos National Laboratory Category: Cloud Properties We report high fidelity observations of the spatial and thermal

  1. CX-010779: Categorical Exclusion Determination

    Office of Energy Efficiency and Renewable Energy (EERE)

    Predictive Large Eddy Simulation (LES) Modeling and Validation for High-Pressure Turbulent Flames and Flashback in Hydrogen-Enriched Gas Turbine CX(s) Applied: A9, B3.6 Date: 08/23/2013 Location(s): Texas Offices(s): National Energy Technology Laboratory

  2. Modeling

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

    Engine Combustion/Modeling - Modelingadmin2015-10-28T01:54:52+00:00 Modelers at the CRF are developing high-fidelity simulation tools for engine combustion and detailed micro-kinetic, surface chemistry modeling tools for catalyst-based exhaust aftertreatment systems. The engine combustion modeling is focused on developing Large Eddy Simulation (LES). LES is being used with closely coupled key target experiments to reveal new understanding of the fundamental processes involved in engine

  3. ITP Chemicals: Technology Roadmap for Computational Fluid Dynamics, January

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

    1999 | Department of Energy Fluid Dynamics, January 1999 ITP Chemicals: Technology Roadmap for Computational Fluid Dynamics, January 1999 PDF icon cfd_roadmap.pdf More Documents & Publications 3-D Combustion Simulation Strategy Status, Future Potential, and Application Issues A Workshop to Identify Research Needs and Impacts in Predictive Simulation for Internal Combustion Engines (PreSICE) Vehicle Technologies Office Merit Review 2015: Large Eddy Simulation (LES) Applied to Advanced

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

    SciTech Connect (OSTI)

    Grinstein, Fernando F [Los Alamos National Laboratory

    2009-01-01

    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.

  5. LES' URENCO-USA Facility | Department of Energy

    Energy Savers [EERE]

    LES' URENCO-USA Facility LES' URENCO-USA Facility PowerPoint slides on LES's URENCO-USA Facility PDF icon LES' URENCO-USA Facility More Documents & Publications Excess Uranium Management 2014 Review of the Potential Impact of DOE Excess Uranium Inventory On the Commercial Markets Memorandum Memorializing Ex Parte Communication

  6. LEM-CF Premixed Tool Kit

    Energy Science and Technology Software Center (OSTI)

    2015-01-19

    The purpose of LEM-CF Premixed Tool Kit is to process premixed flame simulation data from the LEM-CF solver (https://fileshare.craft-tech.com/clusters/view/lem-cf) into a large-eddy simulation (LES) subgrid model database. These databases may be used with a user-defined-function (UDF) that is included in the Tool Kit. The subgrid model UDF may be used with the ANSYS FLUENT flow solver or other commercial flow solvers.

  7. ARM Dev Workshop Plenary Presentation Gustafson 201507.pptx

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

    Development of the LES ARM Symbiotic Simulation and Observation (LASSO) Workflow William I. Gustafson, Principal Investigator Pacific Northwest National Laboratory Andrew M. Vogelmann, Co-principal Investigator Brookhaven National Laboratory January 2014 Measurement Strategy Large-Eddy Simulation Scale (1 to 200 m) Cloud-Resolving Model Scale (1 to 4 km) Mesoscale Model Scale (4 to 20 km) Single-Column Model (100 km) General Circulation Model Scale (10 to 100 km, NCEP/ ECMWF Forcing) ARM

  8. Doug Longman | Argonne National Laboratory

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

    Doug Longman Section Manager - Engine Combustion Research News The complex chemistry of combustion Argonne, Achates Power and Delphi Automotive to investigate new approach to engines E-mail dlongman@anl.gov Projects Combustion Modeling with Detailed Chemistry Effect of Nozzle Orifice Geometry Fuel Spray Modeling High-Fidelity Large Eddy Simulations (LES) Multi-Dimensional Modeling Simulation Approaches for Drop-in Biofuels Virtual Engine Research Institute and Fuels Initiative

  9. LES ARM Symbiotic Simulation and Observation (LASSO) Implementation...

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

    Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research ... Geophysical Union ARM DOE Atmospheric Radiation Measurement ARSCL ARM Remotely-Sensed ...

  10. Modifications to WRFs dynamical core to improve the treatment of moisture

    Office of Scientific and Technical Information (OSTI)

    for large-eddy simulations (Journal Article) | SciTech Connect Journal Article: Modifications to WRFs dynamical core to improve the treatment of moisture for large-eddy simulations Citation Details In-Document Search Title: Modifications to WRFs dynamical core to improve the treatment of moisture for large-eddy simulations Yamaguchi and Feingold (2012) note that the cloud fields in their large-eddy simulations (LESs) of marine stratocumulus using the Weather Research and Forecasting (WRF)

  11. Sandia Optical Hydrogen-fueled Engine | Department of Energy

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

    09 DOE Hydrogen Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting, May 18-22, 2009 -- Washington D.C. PDF icon ace_03_kaiser.pdf More Documents & Publications Sandia Optical Hydrogen-fueled Engine Large Eddy Simulation (LES) Applied to LTC/Diesel/Hydrogen Engine Combustion Research Optimization of Direct-Injection H2 Combustion Engine Performance, Efficiency, and Emissions

  12. ARM - LASSO Presentations

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

    Presentations LASSO Information LASSO Home LASSO Backgrounder Pilot Phase Begins for Routine Large-Eddy Simulations Pilot Project Timeline Presentations Science LASSO Implementation Strategy Related Information ARM Decadal Vision Archive of LASSO Information e-mail list LASSO Collaboration Letter Contacts William Gustafson, Lead Principal Investigator Andrew Vogelmann, Co-Principal Investigator Hanna Goss, Media Contact LASSO Presentations ARM Radar Workshop, February 25, 2016 LES ARM Symbiotic

  13. The role of large eddy fluctuations in the Madison Dynamo Experiment

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

    magnetic field. We also examine the mean-field like effects of large-scale (stable) eddies in the Dudley- James 1989 two-vortex dynamo (that the MDE was based upon). Rotating ...

  14. 1

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

    numerical models. QJRMS., 125, 391-423. Stevens, B., C. -H. Moeng, and P. P. Sullivan, 1999: Large-eddy simulations of radiatively driven convection: Sensitivities to the...

  15. Modifications to WRFs dynamical core to improve the treatment...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Modifications to WRFs dynamical core to improve the treatment of moisture for large-eddy simulations Citation Details In-Document Search Title: Modifications to ...

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

    Office of Scientific and Technical Information (OSTI)

    show that the rate of turbulent dissipation is comparable to the convective luminosity. ... LARGE-EDDY SIMULATION; LAYERS; LUMINOSITY; MEAN-FIELD THEORY; MIXING; ...

  17. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... Large Eddy Simulation of Turbulence Chemistry Interactions in Reacting Flows: Experiences ... dissipation rate from one-dimensional (1D) or two-dimensional (2D) gradient measurements. ...

  18. Research Highlight

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

    per cm-3) droplet concentrations. Six realizations are shown for each droplet concentration. Large-eddy simulation time series output of daytime thin stratiform LWP for low...

  19. RACORO continental boundary layer cloud investigations. 3. Separation of parameterization biases in single-column model CAM5 simulations of shallow cumulus

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

    Lin, Wuyin; Liu, Yangang; Vogelmann, Andrew M.; Fridlind, Ann; Endo, Satoshi; Song, Hua; Feng, Sha; Toto, Tami; Li, Zhijin; Zhang, Minghua

    2015-06-19

    Climatically important low-level clouds are commonly misrepresented in climate models. The FAst-physics System TEstbed and Research (FASTER) project has constructed case studies from the Atmospheric Radiation Measurement (ARM) Climate Research Facility's Southern Great Plain site during the RACORO aircraft campaign to facilitate research on model representation of boundary-layer clouds. This paper focuses on using the single-column Community Atmosphere Model version 5 (SCAM5) simulations of a multi-day continental shallow cumulus case to identify specific parameterization causes of low-cloud biases. Consistent model biases among the simulations driven by a set of alternative forcings suggest that uncertainty in the forcing plays only amoreĀ Ā» relatively minor role. In-depth analysis reveals that the model's shallow cumulus convection scheme tends to significantly under-produce clouds during the times when shallow cumuli exist in the observations, while the deep convective and stratiform cloud schemes significantly over-produce low-level clouds throughout the day. The links between model biases and the underlying assumptions of the shallow cumulus scheme are further diagnosed with the aid of large-eddy simulations and aircraft measurements, and by suppressing the triggering of the deep convection scheme. It is found that the weak boundary layer turbulence simulated is directly responsible for the weak cumulus activity and the simulated boundary layer stratiform clouds. Increased vertical and temporal resolutions are shown to lead to stronger boundary layer turbulence and reduction of low-cloud biases.Ā«Ā less

  20. RACORO continental boundary layer cloud investigations. 3. Separation of parameterization biases in single-column model CAM5 simulations of shallow cumulus

    SciTech Connect (OSTI)

    Lin, Wuyin; Liu, Yangang; Vogelmann, Andrew M.; Fridlind, Ann; Endo, Satoshi; Song, Hua; Feng, Sha; Toto, Tami; Li, Zhijin; Zhang, Minghua

    2015-06-19

    Climatically important low-level clouds are commonly misrepresented in climate models. The FAst-physics System TEstbed and Research (FASTER) project has constructed case studies from the Atmospheric Radiation Measurement (ARM) Climate Research Facility's Southern Great Plain site during the RACORO aircraft campaign to facilitate research on model representation of boundary-layer clouds. This paper focuses on using the single-column Community Atmosphere Model version 5 (SCAM5) simulations of a multi-day continental shallow cumulus case to identify specific parameterization causes of low-cloud biases. Consistent model biases among the simulations driven by a set of alternative forcings suggest that uncertainty in the forcing plays only a relatively minor role. In-depth analysis reveals that the model's shallow cumulus convection scheme tends to significantly under-produce clouds during the times when shallow cumuli exist in the observations, while the deep convective and stratiform cloud schemes significantly over-produce low-level clouds throughout the day. The links between model biases and the underlying assumptions of the shallow cumulus scheme are further diagnosed with the aid of large-eddy simulations and aircraft measurements, and by suppressing the triggering of the deep convection scheme. It is found that the weak boundary layer turbulence simulated is directly responsible for the weak cumulus activity and the simulated boundary layer stratiform clouds. Increased vertical and temporal resolutions are shown to lead to stronger boundary layer turbulence and reduction of low-cloud biases.

  1. NETL F 451.1/1-1, Categorical Exclusion Designation Form

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

    EE0007278 Penn State University University Park, PA Sandia National Laboratory (CX form only applies to Sandia National Laboratory activities) EE/TDIC/ETD/EERE Team Nicholas D'Amico Development and Validation of Predictive Models for In-Cylinder Radiation... Large-eddy simulation (LES) will be performed by Sandia using a single unified code framework called RAPTOR. The Sandia contributions pertain to Tasks 2 and 5 of the Work Plan (RAPTOR-based tasks). Tasks 2 & 5 of work plan NICHOLAS

  2. Microsoft Word - Advanced Solution Verification of CFD Solutions for LES of GTRF_Rider_August23.docx

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

    VUQ.VVDA.P4.03 Jim Stewart SNL Completed: 8/31/2012 CASL-U-2012-0132-000 Advanced Solution Verification of CFD Solutions for LES o f R elevance t o GTRF Estimates. William J. Rider and James R. Kamm Sandia N ational L aboratories Albuquerque, NM 87185 August 31, 2012 SAND 2 012---7199P Summary The purpose of this work is to d emonstrate advanced solution verification (i.e., numerical error estimation) techniques on computational fluid dynamics simulations of interest to CASL. The specific case

  3. Locally Employed Staff (LES)/Foreign Service National (FSN) of the Year

    Office of Environmental Management (EM)

    Award | Department of Energy Locally Employed Staff (LES)/Foreign Service National (FSN) of the Year Award Locally Employed Staff (LES)/Foreign Service National (FSN) of the Year Award The Locally Employed Staff (LES)/Foreign Service National (FSN) of the Year Award is designed to recognize special contributions made by the Department's LES/FSN's in achieving the U.S. Department of Energy's (DOE) and United States Government's (USG) foreign policy goals and objectives. The LES/FSN of the

  4. Petascale algorithms for reactor hydrodynamics.

    SciTech Connect (OSTI)

    Fischer, P.; Lottes, J.; Pointer, W. D.; Siegel, A.

    2008-01-01

    We describe recent algorithmic developments that have enabled large eddy simulations of reactor flows on up to P = 65, 000 processors on the IBM BG/P at the Argonne Leadership Computing Facility. Petascale computing is expected to play a pivotal role in the design and analysis of next-generation nuclear reactors. Argonne's SHARP project is focused on advanced reactor simulation, with a current emphasis on modeling coupled neutronics and thermal-hydraulics (TH). The TH modeling comprises a hierarchy of computational fluid dynamics approaches ranging from detailed turbulence computations, using DNS (direct numerical simulation) and LES (large eddy simulation), to full core analysis based on RANS (Reynolds-averaged Navier-Stokes) and subchannel models. Our initial study is focused on LES of sodium-cooled fast reactor cores. The aim is to leverage petascale platforms at DOE's Leadership Computing Facilities (LCFs) to provide detailed information about heat transfer within the core and to provide baseline data for less expensive RANS and subchannel models.

  5. Minimalist Model of Ice Microphysics in Mixed-phase Stratiform Clouds

    SciTech Connect (OSTI)

    Yang, F.; Ovchinnikov, Mikhail; Shaw, Raymond A.

    2013-07-28

    The question of whether persistent ice crystal precipitation from super cooled layer clouds can be explained by time-dependent, stochastic ice nucleation is explored using an approximate, analytical model, and a large-eddy simulation (LES) cloud model. The updraft velocity in the cloud defines an accumulation zone, where small ice particles cannot fall out until they are large enough, which will increase the residence time of ice particles in the cloud. Ice particles reach a quasi-steady state between growth by vapor deposition and fall speed at cloud base. The analytical model predicts that ice water content (wi) has a 2.5 power law relationship with ice number concentration ni. wi and ni from a LES cloud model with stochastic ice nucleation also confirm the 2.5 power law relationship. The prefactor of the power law is proportional to the ice nucleation rate, and therefore provides a quantitative link to observations of ice microphysical properties.

  6. A new class of finite element variational multiscale turbulence models for incompressible magnetohydrodynamics

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

    Sondak, D.; Shadid, J. N.; Oberai, A. A.; Pawlowski, R. P.; Cyr, E. C.; Smith, T. M.

    2015-04-29

    New large eddy simulation (LES) turbulence models for incompressible magnetohydrodynamics (MHD) derived from the variational multiscale (VMS) formulation for finite element simulations are introduced. The new models include the variational multiscale formulation, a residual-based eddy viscosity model, and a mixed model that combines both of these component models. Each model contains terms that are proportional to the residual of the incompressible MHD equations and is therefore numerically consistent. Moreover, each model is also dynamic, in that its effect vanishes when this residual is small. The new models are tested on the decaying MHD Taylor Green vortex at low and highmoreĀ Ā» Reynolds numbers. The evaluation of the models is based on comparisons with available data from direct numerical simulations (DNS) of the time evolution of energies as well as energy spectra at various discrete times. Thus a numerical study, on a sequence of meshes, is presented that demonstrates that the large eddy simulation approaches the DNS solution for these quantities with spatial mesh refinement.Ā«Ā less

  7. A new class of finite element variational multiscale turbulence models for incompressible magnetohydrodynamics

    SciTech Connect (OSTI)

    Sondak, D.; Shadid, J. N.; Oberai, A. A.; Pawlowski, R. P.; Cyr, E. C.; Smith, T. M.

    2015-04-29

    New large eddy simulation (LES) turbulence models for incompressible magnetohydrodynamics (MHD) derived from the variational multiscale (VMS) formulation for finite element simulations are introduced. The new models include the variational multiscale formulation, a residual-based eddy viscosity model, and a mixed model that combines both of these component models. Each model contains terms that are proportional to the residual of the incompressible MHD equations and is therefore numerically consistent. Moreover, each model is also dynamic, in that its effect vanishes when this residual is small. The new models are tested on the decaying MHD Taylor Green vortex at low and high Reynolds numbers. The evaluation of the models is based on comparisons with available data from direct numerical simulations (DNS) of the time evolution of energies as well as energy spectra at various discrete times. Thus a numerical study, on a sequence of meshes, is presented that demonstrates that the large eddy simulation approaches the DNS solution for these quantities with spatial mesh refinement.

  8. Wind Simulation

    Energy Science and Technology Software Center (OSTI)

    2008-12-31

    The Software consists of a spreadsheet written in Microsoft Excel that provides an hourly simulation of a wind energy system, which includes a calculation of wind turbine output as a power-curve fit of wind speed.

  9. Multi-scale thermalhydraulic analyses performed in Nuresim and Nurisp projects

    SciTech Connect (OSTI)

    Bestion, D.; Lucas, D.; Anglart, H.; Niceno, B.; Vyskocil, L.

    2012-07-01

    The NURESIM and NURISP successive projects of the 6. and 7. European Framework Programs joined the efforts of 21 partners for developing and validating a reference multi-physics and multi-scale platform for reactor simulation. The platform includes system codes, component codes, and also CFD or CMFD simulation tools. Fine scale CFD simulations are useful for a better understanding of physical processes, for the prediction of small scale geometrical effects and for solving problems that require a fine space and/or time resolution. Many important safety issues usually treated at the system scale may now benefit from investigations at a CFD scale. The Pressurized Thermal Shock is investigated using several simulation scales including Direct Numerical Simulation, Large Eddy Simulation, Very Large Eddy Simulation and RANS approaches. At the end a coupling of system code and CFD is applied. Condensation Induced Water-Hammer was also investigated at both CFD and 1-D scale. Boiling flow in a reactor core up to Departure from Nucleate Boiling or Dry-Out is investigated at scales much smaller than the classical subchannel analysis codes. DNS was used to investigate very local processes whereas CFD in both RANS and LES was used to simulate bubbly flow and Euler-Lagrange simulations were used for annular mist flow investigations. Loss of Coolant Accidents are usually treated by system codes. Some related issues are now revisited at the CFD scale. In each case the progress of the analysis is summarized and the benefit of the multi-scale approach is shown. (authors)

  10. RACORO continental boundary layer cloud investigations. Part I: Case study development and ensemble large-scale forcings

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

    Vogelmann, Andrew M.; Fridlind, Ann M.; Toto, Tami; Endo, Satoshi; Lin, Wuyin; Wang, Jian; Feng, Sha; Zhang, Yunyan; Turner, David D.; Liu, Yangang; et al

    2015-06-19

    Observation-based modeling case studies of continental boundary layer clouds have been developed to study cloudy boundary layers, aerosol influences upon them, and their representation in cloud- and global-scale models. Three 60-hour case study periods span the temporal evolution of cumulus, stratiform, and drizzling boundary layer cloud systems, representing mixed and transitional states rather than idealized or canonical cases. Based on in-situ measurements from the RACORO field campaign and remote-sensing observations, the cases are designed with a modular configuration to simplify use in large-eddy simulations (LES) and single-column models. Aircraft measurements of aerosol number size distribution are fit to lognormal functionsmoreĀ Ā» for concise representation in models. Values of the aerosol hygroscopicity parameter, Īŗ, are derived from observations to be ~0.10, which are lower than the 0.3 typical over continents and suggestive of a large aerosol organic fraction. Ensemble large-scale forcing datasets are derived from the ARM variational analysis, ECMWF forecasts, and a multi-scale data assimilation system. The forcings are assessed through comparison of measured bulk atmospheric and cloud properties to those computed in 'trial' large-eddy simulations, where more efficient run times are enabled through modest reductions in grid resolution and domain size compared to the full-sized LES grid. Simulations capture many of the general features observed, but the state-of-the-art forcings were limited at representing details of cloud onset, and tight gradients and high-resolution transients of importance. Methods for improving the initial conditions and forcings are discussed. The cases developed are available to the general modeling community for studying continental boundary clouds.Ā«Ā less

  11. RACORO continental boundary layer cloud investigations. Part I: Case study development and ensemble large-scale forcings

    SciTech Connect (OSTI)

    Vogelmann, Andrew M.; Fridlind, Ann M.; Toto, Tami; Endo, Satoshi; Lin, Wuyin; Wang, Jian; Feng, Sha; Zhang, Yunyan; Turner, David D.; Liu, Yangang; Li, Zhijin; Xie, Shaocheng; Ackerman, Andrew S.; Zhang, Minghua; Khairoutdinov, Marat

    2015-06-19

    Observation-based modeling case studies of continental boundary layer clouds have been developed to study cloudy boundary layers, aerosol influences upon them, and their representation in cloud- and global-scale models. Three 60-hour case study periods span the temporal evolution of cumulus, stratiform, and drizzling boundary layer cloud systems, representing mixed and transitional states rather than idealized or canonical cases. Based on in-situ measurements from the RACORO field campaign and remote-sensing observations, the cases are designed with a modular configuration to simplify use in large-eddy simulations (LES) and single-column models. Aircraft measurements of aerosol number size distribution are fit to lognormal functions for concise representation in models. Values of the aerosol hygroscopicity parameter, Īŗ, are derived from observations to be ~0.10, which are lower than the 0.3 typical over continents and suggestive of a large aerosol organic fraction. Ensemble large-scale forcing datasets are derived from the ARM variational analysis, ECMWF forecasts, and a multi-scale data assimilation system. The forcings are assessed through comparison of measured bulk atmospheric and cloud properties to those computed in 'trial' large-eddy simulations, where more efficient run times are enabled through modest reductions in grid resolution and domain size compared to the full-sized LES grid. Simulations capture many of the general features observed, but the state-of-the-art forcings were limited at representing details of cloud onset, and tight gradients and high-resolution transients of importance. Methods for improving the initial conditions and forcings are discussed. The cases developed are available to the general modeling community for studying continental boundary clouds.

  12. Hybrid Simulator

    Energy Science and Technology Software Center (OSTI)

    2005-10-15

    HybSim (short for Hybrid Simulator) is a flexible, easy to use screening tool that allows the user to quanti the technical and economic benefits of installing a village hybrid generating system and simulates systems with any combination of Ā—Diesel generator sets Ā—Photovoltaic arrays -Wind Turbines and -Battery energy storage systems Most village systems (or small population sites such as villages, remote military bases, small communities, independent or isolated buildings or centers) depend on diesel generationmoreĀ Ā» systems for their source of energy. HybSim allows the user to determine other "sources" of energy that can greatly reduce the dollar to kilo-watt hour ratio. Supported by the DOE, Energy Storage Program, HybSim was initially developed to help analyze the benefits of energy storage systems in Alaskan villages. Soon after its development, other sources of energy were added providing the user with a greater range of analysis opportunities and providing the village with potentially added savings. In addition to village systems, HybSim has generated interest for use from military institutions in energy provisions and USAID for international village analysis.Ā«Ā less

  13. Evaluation of a 1000 MW Commercial Ultra Super-Critical Coal...

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

    of instantaneous O2 mass fraction in a hypothetical commercial scale 1000 MW, Ultra Super-Critical (USC) coal boiler Large eddy simulation prediction of instantaneous O2 mass...

  14. ARM - Publications: Science Team Meeting Documents

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

    Large Eddy Simulations of Fair-Weather Cumulus Case at SGP Site Zhu, P. and Albrecht, B.A., University of Miami Twelfth Atmospheric Radiation Measurement (ARM) Science Team Meeting...

  15. Microsoft Word - L3 THM ITM P3 01 (Rev 2) - Solution Verification report (2-1-12)

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

    Solution Verification Applied to TransAT Large Eddy Simulations for Smooth Wall Channel Flow With Periodic Boundary Conditions, Revision 1 D. Chatzikyriakou, J. Buongiorno, Massachusetts Institute of Technology C. Narayanan, ASCOMP GmbH February 28, 2012 CASL-U-2011-0184-001 Solution Verification Applied to TransAT Large Eddy Simulations for Smooth Wall Channel Flow With Periodic Boundary Conditions REVISION 1 D. Chatzikyriakou 1 , J. Buongiorno 1* , C. Narayanan 2 1 Massachusetts Institute of

  16. Analysis of turbulent transport and mixing in transitional Rayleigh/Taylor unstable flow using direct numerical simulation data

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

    Schilling, Oleg; Mueschke, Nicholas J.

    2010-10-18

    Data from a 1152X760X1280 direct numerical simulation (DNS) of a transitional Rayleigh-Taylor mixing layer modeled after a small Atwood number water channel experiment is used to comprehensively investigate the structure of mean and turbulent transport and mixing. The simulation had physical parameters and initial conditions approximating those in the experiment. The budgets of the mean vertical momentum, heavy-fluid mass fraction, turbulent kinetic energy, turbulent kinetic energy dissipation rate, heavy-fluid mass fraction variance, and heavy-fluid mass fraction variance dissipation rate equations are constructed using Reynolds averaging applied to the DNS data. The relative importance of mean and turbulent production, turbulent dissipationmore »and destruction, and turbulent transport are investigated as a function of Reynolds number and across the mixing layer to provide insight into the flow dynamics not presently available from experiments. The analysis of the budgets supports the assumption for small Atwood number, Rayleigh/Taylor driven flows that the principal transport mechanisms are buoyancy production, turbulent production, turbulent dissipation, and turbulent diffusion (shear and mean field production are negligible). As the Reynolds number increases, the turbulent production in the turbulent kinetic energy dissipation rate equation becomes the dominant production term, while the buoyancy production plateaus. Distinctions between momentum and scalar transport are also noted, where the turbulent kinetic energy and its dissipation rate both grow in time and are peaked near the center plane of the mixing layer, while the heavy-fluid mass fraction variance and its dissipation rate initially grow and then begin to decrease as mixing progresses and reduces density fluctuations. All terms in the transport equations generally grow or decay, with no qualitative change in their profile, except for the pressure flux contribution to the total turbulent kinetic energy flux, which changes sign early in time (a countergradient effect). The production-to-dissipation ratios corresponding to the turbulent kinetic energy and heavy-fluid mass fraction variance are large and vary strongly at small evolution times, decrease with time, and nearly asymptote as the flow enters a self-similar regime. The late-time turbulent kinetic energy production-to-dissipation ratio is larger than observed in shear-driven turbulent flows. The order of magnitude estimates of the terms in the transport equations are shown to be consistent with the DNS at late-time, and also confirms both the dominant terms and their evolutionary behavior. These results are useful for identifying the dynamically important terms requiring closure, and assessing the accuracy of the predictions of Reynolds-averaged Navier-Stokes and large-eddy simulation models of turbulent transport and mixing in transitional Rayleigh-Taylor instability-generated flow.« less

  17. CGILS: Results from the First Phase of an International Project to Understand the Physical Mechanisms of Low Cloud Feedbacks in Single Column Models

    SciTech Connect (OSTI)

    Zhang, Minghua; Bretherton, Christopher S.; Blossey, Peter; Austin, Phillip A.; Bacmeister, J.; Bony, Sandrine; Brient, Florent; Cheedela, Suvarchal K.; Cheng, Anning; Del Genio, Anthony D.; De Roode, Stephan R.; Endo , Satoshi; Franklin, Charmaine N.; Golaz, Jean-Christophe; Hannay, Cecile; Heus, Thijs; Isotta, Francesco A.; Jean-Louis, Dufresne; Kang, In-Sik; Kawai, Hideaki; Koehler, M.; Larson, Vincent E.; Liu, Yangang; Lock, Adrian; Lohmann, U.; Khairoutdinov, Marat; Molod, Andrea M.; Neggers, Roel; Rasch, Philip J.; Sandu, Irina; Senkbeil, Ryan; Siebesma, A. P.; Siegenthaler-Le Drian, Colombe; Stevens, Bjorn; Suarez, Max; Xu, Kuan-Man; Von Salzen, Knut; Webb, Mark; Wolf, Audrey; Zhao, M.

    2013-12-26

    Large Eddy Models (LES) and Single Column Models (SCM) are used in a surrogate climate change 101 to investigate the physical mechanism of low cloud feedbacks in climate models. Enhanced surface-102 driven boundary layer turbulence and shallow convection in a warmer climate are found to be 103 dominant mechanisms in SCMs.

  18. Building a Particle Simulator

    SciTech Connect (OSTI)

    Weaver, Brian Phillip; Williams, Brian J.

    2015-10-06

    The purpose of this manuscript is to illustrate how to use the simulator we have developed to generate counts from simulated spectra.

  19. Reframing Accelerator Simulations

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

    Simulations Mori-1.png Key Challenges: Use advanced simulation tools to study the feasibility of plasma-based linear colliders and to optimize conceptual designs. Much of the...

  20. FUEL-FLEXIBLE GASIFICATION-COMBUSTION TECHNOLOGY FOR PRODUCTION OF H2 AND SEQUESTRATION-READY CO2

    SciTech Connect (OSTI)

    George Rizeq; Janice West; Arnaldo Frydman; Raul Subia; Vladimir Zamansky; Tomasz Wiltowski; Tom Miles; Bruce Springsteen

    2002-04-30

    Further development of a combustion Large Eddy Simulation (LES) code for the design of advanced gaseous combustion systems is described in this sixth quarterly report. CFD Research Corporation (CFDRC) is developing the LES module within the parallel, unstructured solver included in the commercial CFD-ACE+ software. In this quarter, in-situ adaptive tabulation (ISAT) for efficient chemical rate storage and retrieval was implemented and tested within the Linear Eddy Model (LEM). ISAT type 3 is being tested so that extrapolation can be performed and further improve the retrieval rate. Further testing of the LEM for subgrid chemistry was performed for parallel applications and for multi-step chemistry. Validation of the software on backstep and bluff-body reacting cases were performed. Initial calculations of the SimVal experiment at Georgia Tech using their LES code were performed. Georgia Tech continues the effort to parameterize the LEM over composition space so that a neural net can be used efficiently in the combustion LES code. A new and improved Artificial Neural Network (ANN), with log-transformed output, for the 1-step chemistry was implemented in CFDRC's LES code and gave reasonable results. This quarter, the 2nd consortium meeting was held at CFDRC. Next quarter, LES software development and testing will continue. Alpha testing of the code will continue to be performed on cases of interest to the industrial consortium. Optimization of subgrid models will be pursued, particularly with the ISAT approach. Also next quarter, the demonstration of the neural net approach, for multi-step chemical kinetics speed-up in CFD-ACE+, will be accomplished.

  1. Carbon Capture Simulation Initiative

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

    Capture Simulation Initiative Fact sheet More Information Research Team Members Key Contacts Carbon Capture Simulation Initiative The Carbon Capture Simulation Initiative (CCSI) is a partnership among national laboratories, industry, and academic institutions that is developing, demonstrating and deploying state-of-the-art computational modeling and simulation tools to accelerate the development of carbon capture technologies from discovery to development, demonstration, and ultimately the

  2. Subgrid models for mass and thermal diffusion in turbulent mixing

    SciTech Connect (OSTI)

    Sharp, David H; Lim, Hyunkyung; Li, Xiao - Lin; Gilmm, James G

    2008-01-01

    We are concerned with the chaotic flow fields of turbulent mixing. Chaotic flow is found in an extreme form in multiply shocked Richtmyer-Meshkov unstable flows. The goal of a converged simulation for this problem is twofold: to obtain converged solutions for macro solution features, such as the trajectories of the principal shock waves, mixing zone edges, and mean densities and velocities within each phase, and also for such micro solution features as the joint probability distributions of the temperature and species concentration. We introduce parameterized subgrid models of mass and thermal diffusion, to define large eddy simulations (LES) that replicate the micro features observed in the direct numerical simulation (DNS). The Schmidt numbers and Prandtl numbers are chosen to represent typical liquid, gas and plasma parameter values. Our main result is to explore the variation of the Schmidt, Prandtl and Reynolds numbers by three orders of magnitude, and the mesh by a factor of 8 per linear dimension (up to 3200 cells per dimension), to allow exploration of both DNS and LES regimes and verification of the simulations for both macro and micro observables. We find mesh convergence for key properties describing the molecular level of mixing, including chemical reaction rates between the distinct fluid species. We find results nearly independent of Reynolds number for Re 300, 6000, 600K . Methodologically, the results are also new. In common with the shock capturing community, we allow and maintain sharp solution gradients, and we enhance these gradients through use of front tracking. In common with the turbulence modeling community, we include subgrid scale models with no adjustable parameters for LES. To the authors' knowledge, these two methodologies have not been previously combined. In contrast to both of these methodologies, our use of Front Tracking, with DNS or LES resolution of the momentum equation at or near the Kolmogorov scale, but without resolving the Batchelor scale, allows a feasible approach to the modeling of high Schmidt number flows.

  3. Insights from modeling and observational evaluation of a precipitating continental cumulus event observed during the MC3E field campaign

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

    Mechem, David B.; Giangrande, Scott E.; Wittman, Carly S.; Borque, Paloma; Toto, Tami; Kollias, Pavlos

    2015-03-13

    A case of shallow cumulus and precipitating cumulus congestus sampled at the Atmospheric Radiation Measurement (ARM) Program Southern Great Plains (SGP) supersite is analyzed using a multi-sensor observational approach and numerical simulation. Observations from a new radar suite surrounding the facility are used to characterize the evolving statistical behavior of the precipitating cloud system. This is accomplished using distributions of different measures of cloud geometry and precipitation properties. Large-eddy simulation (LES) with size-resolved (bin) microphysics is employed to determine the forcings most important in producing the salient aspects of the cloud system captured in the radar observations. Our emphasis ismoreĀ Ā» on assessing the importance of time-varying vs. steady-state large-scale forcing on the model's ability to reproduce the evolutionary behavior of the cloud system. Additional consideration is given to how the characteristic spatial scale and homogeneity of the forcing imposed on the simulation influences the evolution of cloud system properties. Results indicate that several new scanning radar estimates such as distributions of cloud top are useful to differentiate the value of time-varying (or at least temporally well-matched) forcing on LES solution fidelity.Ā«Ā less

  4. Insights from modeling and observational evaluation of a precipitating continental cumulus event observed during the MC3E field campaign

    SciTech Connect (OSTI)

    Mechem, David B.; Giangrande, Scott E.; Wittman, Carly S.; Borque, Paloma; Toto, Tami; Kollias, Pavlos

    2015-03-13

    A case of shallow cumulus and precipitating cumulus congestus sampled at the Atmospheric Radiation Measurement (ARM) Program Southern Great Plains (SGP) supersite is analyzed using a multi-sensor observational approach and numerical simulation. Observations from a new radar suite surrounding the facility are used to characterize the evolving statistical behavior of the precipitating cloud system. This is accomplished using distributions of different measures of cloud geometry and precipitation properties. Large-eddy simulation (LES) with size-resolved (bin) microphysics is employed to determine the forcings most important in producing the salient aspects of the cloud system captured in the radar observations. Our emphasis is on assessing the importance of time-varying vs. steady-state large-scale forcing on the model's ability to reproduce the evolutionary behavior of the cloud system. Additional consideration is given to how the characteristic spatial scale and homogeneity of the forcing imposed on the simulation influences the evolution of cloud system properties. Results indicate that several new scanning radar estimates such as distributions of cloud top are useful to differentiate the value of time-varying (or at least temporally well-matched) forcing on LES solution fidelity.

  5. Electrical Circuit Simulation Code

    Energy Science and Technology Software Center (OSTI)

    2001-08-09

    Massively-Parallel Electrical Circuit Simulation Code. CHILESPICE is a massively-arallel distributed-memory electrical circuit simulation tool that contains many enhanced radiation, time-based, and thermal features and models. Large scale electronic circuit simulation. Shared memory, parallel processing, enhance convergence. Sandia specific device models.

  6. Weld arc simulator

    DOE Patents [OSTI]

    Burr, Melvin J. (Westminster, CO)

    1990-01-30

    An arc voltage simulator for an arc welder permits the welder response to a variation in arc voltage to be standardized. The simulator uses a linear potentiometer connected to the electrode to provide a simulated arc voltage at the electrode that changes as a function of electrode position.

  7. Flow topologies and turbulence scales in a jet-in-cross-flow

    SciTech Connect (OSTI)

    Oefelein, Joseph C.; Ruiz, Anthony M.; Lacaze, Guilhem

    2015-04-03

    This study presents a detailed analysis of the flow topologies and turbulence scales in the jet-in-cross-flow experiment of [Su and Mungal JFM 2004]. The analysis is performed using the Large Eddy Simulation (LES) technique with a highly resolved grid and time-step and well controlled boundary conditions. This enables quantitative agreement with the first and second moments of turbulence statistics measured in the experiment. LES is used to perform the analysis since experimental measurements of time-resolved 3D fields are still in their infancy and because sampling periods are generally limited with direct numerical simulation. A major focal point is the comprehensive characterization of the turbulence scales and their evolution. Time-resolved probes are used with long sampling periods to obtain maps of the integral scales, Taylor microscales, and turbulent kinetic energy spectra. Scalar-fluctuation scales are also quantified. In the near-field, coherent structures are clearly identified, both in physical and spectral space. Along the jet centerline, turbulence scales grow according to a classical one-third power law. However, the derived maps of turbulence scales reveal strong inhomogeneities in the flow. From the modeling perspective, these insights are useful to design optimized grids and improve numerical predictions in similar configurations.

  8. Flow topologies and turbulence scales in a jet-in-cross-flow

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

    Oefelein, Joseph C.; Ruiz, Anthony M.; Lacaze, Guilhem

    2015-04-03

    This study presents a detailed analysis of the flow topologies and turbulence scales in the jet-in-cross-flow experiment of [Su and Mungal JFM 2004]. The analysis is performed using the Large Eddy Simulation (LES) technique with a highly resolved grid and time-step and well controlled boundary conditions. This enables quantitative agreement with the first and second moments of turbulence statistics measured in the experiment. LES is used to perform the analysis since experimental measurements of time-resolved 3D fields are still in their infancy and because sampling periods are generally limited with direct numerical simulation. A major focal point is the comprehensivemoreĀ Ā» characterization of the turbulence scales and their evolution. Time-resolved probes are used with long sampling periods to obtain maps of the integral scales, Taylor microscales, and turbulent kinetic energy spectra. Scalar-fluctuation scales are also quantified. In the near-field, coherent structures are clearly identified, both in physical and spectral space. Along the jet centerline, turbulence scales grow according to a classical one-third power law. However, the derived maps of turbulence scales reveal strong inhomogeneities in the flow. From the modeling perspective, these insights are useful to design optimized grids and improve numerical predictions in similar configurations.Ā«Ā less

  9. Reactor refueling machine simulator

    SciTech Connect (OSTI)

    Rohosky, T.L.; Swidwa, K.J.

    1987-10-13

    This patent describes in combination: a nuclear reactor; a refueling machine having a bridge, trolley and hoist each driven by a separate motor having feedback means for generating a feedback signal indicative of movement thereof. The motors are operable to position the refueling machine over the nuclear reactor for refueling the same. The refueling machine also has a removable control console including means for selectively generating separate motor signals for operating the bridge, trolley and hoist motors and for processing the feedback signals to generate an indication of the positions thereof, separate output leads connecting each of the motor signals to the respective refueling machine motor, and separate input leads for connecting each of the feedback means to the console; and a portable simulator unit comprising: a single simulator motor; a single simulator feedback signal generator connected to the simulator motor for generating a simulator feedback signal in response to operation of the simulator motor; means for selectively connecting the output leads of the console to the simulator unit in place of the refueling machine motors, and for connecting the console input leads to the simulator unit in place of the refueling machine motor feedback means; and means for driving the single simulator motor in response to any of the bridge, trolley or hoist motor signals generated by the console and means for applying the simulator feedback signal to the console input lead associated with the motor signal being generated by the control console.

  10. Fast Analysis and Simulation Team | NISAC

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

    NISACFast Analysis and Simulation Team

  11. 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 century. Get Expertise David Harradine Physical Chemistry and Applied Spectroscopy Email Josh Smith Chemistry Communications Email The inherent knowledge of transformation has beguiled sorcerers and scientists alike. Data Analysis and Modeling & Simulation for the Chemical Sciences Project Description Almos every

  12. Device Simulation Tool - JCAP

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

    PAZ0036_v2.jpg Device Simulation Tool Research Why Solar Fuels Goals & Objectives Thrust 1 Thrust 2 Thrust 3 Thrust 4 Publications Research Highlights Videos Innovations User Facilities Expert Team Benchmarking Database Device Simulation Tool XPS Spectral Database Research Introduction Why Solar Fuels? Goals & Objectives Thrusts Thrust 1 Thrust 2 Thrust 3 Thrust 4 Library Publications Research Highlights Videos Resources User Facilities Expert Team Benchmarking Database Device Simulation

  13. Modeling & Simulation publications

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

    Modeling & Simulation Ā» Modeling & Simulation Publications Modeling & Simulation publications Research into alternative forms of energy, especially energy security, is one of the major national security imperatives of this century. Get Expertise David Harradine Physical Chemistry and Applied Spectroscopy Email Josh Smith Chemistry Email The inherent knowledge of transformation has beguiled sorcerers and scientists alike. D.A. Horner, F. Lambert, J.D. Kress, and L.A. Collins,

  14. Advanced Simulation Capability for

    Office of Environmental Management (EM)

    Advanced Simulation & Computing pro- grams as well as collaborating with the Offices of Science, Fossil Energy, and Nuclear Energy. Challenge Current groundwater and soil...

  15. Whole Building Energy Simulation

    Broader source: Energy.gov [DOE]

    Whole building energy simulation, also referred to as energy modeling, can and should be incorporated early during project planning to provide energy impact feedback for which design considerations...

  16. Les Houches Physics at TeV Colliders 2005 Beyond the Standard Model Working Group: Summary Report

    SciTech Connect (OSTI)

    Allanach, B.C.; Grojean, C.; Skands, P.; Accomando, E.; Azuelos, G.; Baer, H.; Balazs, C.; Belanger, G.; Benakli, K.; Boudjema, F.; Brelier, B.; Bunichev, V.; Cacciapaglia, G.; Carena, M.; Choudhury, D.; Delsart, P.-A.; De Sanctis, U.; Desch, K.; Dobrescu, B.A.; Dudko, L.; El Kacimi, M.; /Saclay, SPhT /CERN /Fermilab /INFN, Turin /Turin U. /Montreal U. /TRIUMF /Florida State U. /Argonne /Annecy, LAPTH /Paris, LPTHE /Moscow State U. /Cornell U., CIHEP /Delhi U. /Milan U. /INFN, Milan /Freiburg U. /Cadi Ayyad U., Marrakech /Orsay, LPT /Oslo U. /Lancaster U.

    2006-03-17

    The work contained herein constitutes a report of the ''Beyond the Standard Model'' working group for the Workshop ''Physics at TeV Colliders'', Les Houches, France, 2-20 May, 2005. We present reviews of current topics as well as original research carried out for the workshop. Supersymmetric and non-supersymmetric models are studied, as well as computational tools designed in order to facilitate their phenomenology.

  17. A Computational Study of the Aerodynamics and Aeroacoustics of a Flatback Airfoil Using Hybrid RANS-LES

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

    Computational Study of the Aerodynamics and Aeroacoustics of a Flatback Airfoil Using Hybrid RANS-LES Christopher Stone āˆ— Computational Science & Engineering, Athens, GA, 30606, USA Matthew Barone ā€  Sandia National Laboratories, Albuquerque, NM, 87185-1124, USA C. Eric Lynch ā€” and Marilyn J. Smith Ā§ Georgia Institute of Technology, Atlanta, Georgia, 30332-0150, USA This work compares the aerodynamic and aeroacoustic predictions for flatback air- foil geometries obtained by applying

  18. Radiation detector spectrum simulator

    DOE Patents [OSTI]

    Wolf, M.A.; Crowell, J.M.

    1985-04-09

    A small battery operated nuclear spectrum simulator having a noise source generates pulses with a Gaussian distribution of amplitudes. A switched dc bias circuit cooperating therewith to generate several nominal amplitudes of such pulses and a spectral distribution of pulses that closely simulates the spectrum produced by a radiation source such as Americium 241.

  19. Radio Channel Simulator (RCSM)

    Energy Science and Technology Software Center (OSTI)

    2007-01-31

    This is a simulation package for making site specific predictions of radio signal strength. The software computes received power at discrete grid points as a function of the transmitter location and propagation environment. It is intended for use with wireless network simulation packages and to support wireless network deployments.

  20. Radiation detector spectrum simulator

    DOE Patents [OSTI]

    Wolf, Michael A. (Los Alamos, NM); Crowell, John M. (Los Alamos, NM)

    1987-01-01

    A small battery operated nuclear spectrum simulator having a noise source nerates pulses with a Gaussian distribution of amplitudes. A switched dc bias circuit cooperating therewith generates several nominal amplitudes of such pulses and a spectral distribution of pulses that closely simulates the spectrum produced by a radiation source such as Americium 241.

  1. Damselfly Network Simulator

    Energy Science and Technology Software Center (OSTI)

    2014-04-01

    Damselfly is a model-based parallel network simulator. It can simulate communication patterns of High Performance Computing applications on different network topologies. It outputs steady-state network traffic for a communication pattern, which can help in studying network congestion and its impact on performance.

  2. Converting DYNAMO simulations to Powersim Studio simulations

    SciTech Connect (OSTI)

    Walker, La Tonya Nicole; Malczynski, Leonard A.

    2014-02-01

    DYNAMO is a computer program for building and running 'continuous' simulation models. It was developed by the Industrial Dynamics Group at the Massachusetts Institute of Technology for simulating dynamic feedback models of business, economic, and social systems. The history of the system dynamics method since 1957 includes many classic models built in DYANMO. It was not until the late 1980s that software was built to take advantage of the rise of personal computers and graphical user interfaces that DYNAMO was supplanted. There is much learning and insight to be gained from examining the DYANMO models and their accompanying research papers. We believe that it is a worthwhile exercise to convert DYNAMO models to more recent software packages. We have made an attempt to make it easier to turn these models into a more current system dynamics software language, Powersim © Studio produced by Powersim AS2 of Bergen, Norway. This guide shows how to convert DYNAMO syntax into Studio syntax.

  3. Global Feedback Simulator

    Energy Science and Technology Software Center (OSTI)

    2015-10-29

    GFS is a simulation engine that is used for the characterization of Accelerator performance parameters based on the machine layout, configuration and noise sources. It combines extensively tested Feedback models with a longitudinal phase space tracking simulator along with the interaction between the two via beam-based feedback using a computationally efficient simulation engine. The models include beam instrumentation, considerations on loop delays for in both the R and beam-based feedback loops, as well as themoreĀ Ā» ability to inject noise (both correlated and uncorrelated) at different points of the machine including a full characterization of the electron gun performance parameters.Ā«Ā less

  4. Global Feedback Simulator

    SciTech Connect (OSTI)

    2015-10-29

    GFS is a simulation engine that is used for the characterization of Accelerator performance parameters based on the machine layout, configuration and noise sources. It combines extensively tested Feedback models with a longitudinal phase space tracking simulator along with the interaction between the two via beam-based feedback using a computationally efficient simulation engine. The models include beam instrumentation, considerations on loop delays for in both the R and beam-based feedback loops, as well as the ability to inject noise (both correlated and uncorrelated) at different points of the machine including a full characterization of the electron gun performance parameters.

  5. Analysis of turbulent transport and mixing in transitional Rayleighā€“Taylor unstable flow using direct numerical simulation data

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

    Schilling, Oleg; Mueschke, Nicholas J.

    2010-10-18

    Data from a 1152X760X1280 direct numerical simulation (DNS) of a transitional Rayleigh-Taylor mixing layer modeled after a small Atwood number water channel experiment is used to comprehensively investigate the structure of mean and turbulent transport and mixing. The simulation had physical parameters and initial conditions approximating those in the experiment. The budgets of the mean vertical momentum, heavy-fluid mass fraction, turbulent kinetic energy, turbulent kinetic energy dissipation rate, heavy-fluid mass fraction variance, and heavy-fluid mass fraction variance dissipation rate equations are constructed using Reynolds averaging applied to the DNS data. The relative importance of mean and turbulent production, turbulent dissipationmoreĀ Ā» and destruction, and turbulent transport are investigated as a function of Reynolds number and across the mixing layer to provide insight into the flow dynamics not presently available from experiments. The analysis of the budgets supports the assumption for small Atwood number, Rayleigh/Taylor driven flows that the principal transport mechanisms are buoyancy production, turbulent production, turbulent dissipation, and turbulent diffusion (shear and mean field production are negligible). As the Reynolds number increases, the turbulent production in the turbulent kinetic energy dissipation rate equation becomes the dominant production term, while the buoyancy production plateaus. Distinctions between momentum and scalar transport are also noted, where the turbulent kinetic energy and its dissipation rate both grow in time and are peaked near the center plane of the mixing layer, while the heavy-fluid mass fraction variance and its dissipation rate initially grow and then begin to decrease as mixing progresses and reduces density fluctuations. All terms in the transport equations generally grow or decay, with no qualitative change in their profile, except for the pressure flux contribution to the total turbulent kinetic energy flux, which changes sign early in time (a countergradient effect). The production-to-dissipation ratios corresponding to the turbulent kinetic energy and heavy-fluid mass fraction variance are large and vary strongly at small evolution times, decrease with time, and nearly asymptote as the flow enters a self-similar regime. The late-time turbulent kinetic energy production-to-dissipation ratio is larger than observed in shear-driven turbulent flows. The order of magnitude estimates of the terms in the transport equations are shown to be consistent with the DNS at late-time, and also confirms both the dominant terms and their evolutionary behavior. Thus, these results are useful for identifying the dynamically important terms requiring closure, and assessing the accuracy of the predictions of Reynolds-averaged Navier-Stokes and large-eddy simulation models of turbulent transport and mixing in transitional Rayleigh-Taylor instability-generated flow.Ā«Ā less

  6. A Multi-Year Plan for Enhancing Turbulence Modeling in Hydra-TH Revised and Updated Version 2.0

    SciTech Connect (OSTI)

    Smith, Thomas M.; Berndt, Markus; Baglietto, Emilio; Magolan, Ben

    2015-10-01

    The purpose of this report is to document a multi-year plan for enhancing turbulence modeling in Hydra-TH for the Consortium for Advanced Simulation of Light Water Reactors (CASL) program. Hydra-TH is being developed to the meet the high- fidelity, high-Reynolds number CFD based thermal hydraulic simulation needs of the program. This work is being conducted within the thermal hydraulics methods (THM) focus area. This report is an extension of THM CASL milestone L3:THM.CFD.P10.02 [33] (March, 2015) and picks up where it left off. It will also serve to meet the requirements of CASL THM level three milestone, L3:THM.CFD.P11.04, scheduled for completion September 30, 2015. The objectives of this plan will be met by: maturation of recently added turbulence models, strategic design/development of new models and systematic and rigorous testing of existing and new models and model extensions. While multi-phase turbulent flow simulations are important to the program, only single-phase modeling will be considered in this report. Large Eddy Simulation (LES) is also an important modeling methodology. However, at least in the first year, the focus is on steady-state Reynolds Averaged Navier-Stokes (RANS) turbulence modeling.

  7. An ensemble constrained variational analysis of atmospheric forcing data and its application to evaluate clouds in CAM5: Ensemble 3DCVA and Its Application

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

    Tang, Shuaiqi; Zhang, Minghua; Xie, Shaocheng

    2016-01-05

    Large-scale atmospheric forcing data can greatly impact the simulations of atmospheric process models including Large Eddy Simulations (LES), Cloud Resolving Models (CRMs) and Single-Column Models (SCMs), and impact the development of physical parameterizations in global climate models. This study describes the development of an ensemble variationally constrained objective analysis of atmospheric large-scale forcing data and its application to evaluate the cloud biases in the Community Atmospheric Model (CAM5). Sensitivities of the variational objective analysis to background data, error covariance matrix and constraint variables are described and used to quantify the uncertainties in the large-scale forcing data. Application of the ensemblemoreĀ Ā» forcing in the CAM5 SCM during March 2000 intensive operational period (IOP) at the Southern Great Plains (SGP) of the Atmospheric Radiation Measurement (ARM) program shows systematic biases in the model simulations that cannot be explained by the uncertainty of large-scale forcing data, which points to the deficiencies of physical parameterizations. The SCM is shown to overestimate high clouds and underestimate low clouds. These biases are found to also exist in the global simulation of CAM5 when it is compared with satellite data.Ā«Ā less

  8. Dynamic Power Grid Simulation

    Energy Science and Technology Software Center (OSTI)

    2015-09-14

    GridDyn is a part of power grid simulation toolkit. The code is designed using modern object oriented C++ methods utilizing C++11 and recent Boost libraries to ensure compatibility with multiple operating systems and environments.

  9. Compressible Astrophysics Simulation Code

    Energy Science and Technology Software Center (OSTI)

    2007-07-18

    This is an astrophysics simulation code involving a radiation diffusion module developed at LLNL coupled to compressible hydrodynamics and adaptive mesh infrastructure developed at LBNL. One intended application is to neutrino diffusion in core collapse supernovae.

  10. Fundamentals of plasma simulation

    SciTech Connect (OSTI)

    Forslund, D.W.

    1985-01-01

    With the increasing size and speed of modern computers, the incredibly complex nonlinear properties of plasmas in the laboratory and in space are being successfully explored in increasing depth. Of particular importance have been numerical simulation techniques involving finite size particles on a discrete mesh. After discussing the importance of this means of understanding a variety of nonlinear plasma phenomena, we describe the basic elements of particle-in-cell simulation and their limitations and advantages. The differencing techniques, stability and accuracy issues, data management and optimization issues are discussed by means of a simple example of a particle-in-cell code. Recent advances in simulation methods allowing large space and time scales to be treated with minimal sacrifice in physics are reviewed. Various examples of nonlinear processes successfully studied by plasma simulation will be given.

  11. Theory Modeling and Simulation

    SciTech Connect (OSTI)

    Shlachter, Jack

    2012-08-23

    Los Alamos has a long history in theory, modeling and simulation. We focus on multidisciplinary teams that tackle complex problems. Theory, modeling and simulation are tools to solve problems just like an NMR spectrometer, a gas chromatograph or an electron microscope. Problems should be used to define the theoretical tools needed and not the other way around. Best results occur when theory and experiments are working together in a team.

  12. Xyce parallel electronic simulator.

    SciTech Connect (OSTI)

    Keiter, Eric Richard; Mei, Ting; Russo, Thomas V.; Rankin, Eric Lamont; Schiek, Richard Louis; Thornquist, Heidi K.; Fixel, Deborah A.; Coffey, Todd Stirling; Pawlowski, Roger Patrick; Santarelli, Keith R.

    2010-05-01

    This document is a reference guide to the Xyce Parallel Electronic Simulator, and is a companion document to the Xyce Users' Guide. The focus of this document is (to the extent possible) exhaustively list device parameters, solver options, parser options, and other usage details of Xyce. This document is not intended to be a tutorial. Users who are new to circuit simulation are better served by the Xyce Users' Guide.

  13. Energy Simulation Games Lesson

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

    Ken Walz Unit Title: Energy Efficiency and Renewable Energy (EERE) Subject: Physical, Env, and Social Sciences Lesson Title: Energy Simulation Games Grade Level(s): 6-12 Lesson Length: 1 hours (+ optional time outside class) Date(s): 7/14/2014 * Learning Goal(s) By the end of this lesson, students will have a deeper understanding of Energy Management, Policy, and Decision Making. * Connection to Energy/ Renewable Energy In this assignment you will be using two different energy simulation tools

  14. Modeling & Simulation | NISAC

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

    NISACModeling & Simulation content top Overview Posted by Admin on Feb 13, 2012 in | Comments 0 comments NISAC experts analyze-using modeling and simulation capabilities-critical infrastructure, along with their interdependencies, vulnerabilities, and complexities. Their analyses are used to aid decisionmakers with policy assessment, mitigation planning, education, and training and provide near-real-time assistance to crisis-response organizations. Infrastructure systems are large, complex,

  15. Advanced Simulation and Computing

    National Nuclear Security Administration (NNSA)

    NA-ASC-117R-09-Vol.1-Rev.0 Advanced Simulation and Computing PROGRAM PLAN FY09 October 2008 ASC Focal Point Robert Meisner, Director DOE/NNSA NA-121.2 202-586-0908 Program Plan Focal Point for NA-121.2 Njema Frazier DOE/NNSA NA-121.2 202-586-5789 A Publication of the Office of Advanced Simulation & Computing, NNSA Defense Programs i Contents Executive Summary ----------------------------------------------------------------------------------------------- 1 I. Introduction

  16. Computer simulation | Open Energy Information

    Open Energy Info (EERE)

    Computer simulation Jump to: navigation, search OpenEI Reference LibraryAdd to library Web Site: Computer simulation Author wikipedia Published wikipedia, 2013 DOI Not Provided...

  17. Computation & Simulation > Theory & Computation > Research >...

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

    it. Click above to view. computational2 computational3 In This Section Computation & Simulation Computation & Simulation Extensive combinatorial results and ongoing basic...

  18. Simple Electric Vehicle Simulation

    Energy Science and Technology Software Center (OSTI)

    1993-07-29

    SIMPLEV2.0 is an electric vehicle simulation code which can be used with any IBM compatible personal computer. This general purpose simulation program is useful for performing parametric studies of electric and series hybrid electric vehicle performance on user input driving cycles.. The program is run interactively and guides the user through all of the necessary inputs. Driveline components and the traction battery are described and defined by ASCII files which may be customized by themoreĀ Ā» user. Scaling of these components is also possible. Detailed simulation results are plotted on the PC monitor and may also be printed on a printer attached to the PC.Ā«Ā less

  19. Experiments ? Simulations = Better Nuclear Power Research

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

    Experiments + Simulations Better Nuclear Power Research Experiments Simulations Better Nuclear Power Research Atomic Level Simulations Enhance Characterization of Radiation...

  20. Simulating neural systems with Xyce.

    SciTech Connect (OSTI)

    Schiek, Richard Louis; Thornquist, Heidi K.; Mei, Ting; Warrender, Christina E.; Aimone, James Bradley; Teeter, Corinne; Duda, Alex M.

    2012-12-01

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

  1. CGILS: Results from the First Phase of an International Project to

    Office of Scientific and Technical Information (OSTI)

    Understand the Physical Mechanisms of Low Cloud Feedbacks in Single Column Models (Journal Article) | SciTech Connect CGILS: Results from the First Phase of an International Project to Understand the Physical Mechanisms of Low Cloud Feedbacks in Single Column Models Citation Details In-Document Search Title: CGILS: Results from the First Phase of an International Project to Understand the Physical Mechanisms of Low Cloud Feedbacks in Single Column Models Large Eddy Models (LES) and Single

  2. Battery Particle Simulation

    SciTech Connect (OSTI)

    2014-09-15

    Two simulations show the differences between a battery being drained at a slower rate, over a full hour, versus a faster rate, only six minutes (a tenth of an hour). In both cases battery particles go from being fully charged (green) to fully drained (red), but there are significant differences in the patterns of discharge based on the rate.

  3. Parallel Dislocation Simulator

    Energy Science and Technology Software Center (OSTI)

    2006-10-30

    ParaDiS is software capable of simulating the motion, evolution, and interaction of dislocation networks in single crystals using massively parallel computer architectures. The software is capable of outputting the stress-strain response of a single crystal whose plastic deformation is controlled by the dislocation processes.

  4. PEBBLES Mechanics Simulation Speedup

    SciTech Connect (OSTI)

    Joshua J. Cogliati; Abderrafi M. Ougouag

    2010-05-01

    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.

  5. scramjet engine simulations

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

    scramjet engine simulations - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management Programs

  6. Direct Numerical Simulation

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

    Numerical Simulation - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management Programs Advanced

  7. Advanced Wellbore Thermal Simulator

    Energy Science and Technology Software Center (OSTI)

    1992-03-04

    GEOTEMP2, which is based on the earlier GEOTEMP program, is a wellbore thermal simulator designed for geothermal well drilling and production applications. The code treats natural and forced convection and conduction within the wellbore and heat conduction within the surrounding rock matrix. A variety of well operations can be modeled including injection, production, forward and reverse circulation with gas or liquid, gas or liquid drilling, and two-phase steam injection and production. Well completion with severalmoreĀ Ā» different casing sizes and cement intervals can be modeled. The code allows variables, such as flow rate, to change with time enabling a realistic treatment of well operations. Provision is made in the flow equations to allow the flow areas of the tubing to vary with depth in the wellbore. Multiple liquids can exist in GEOTEMP2 simulations. Liquid interfaces are tracked through the tubing and annulus as one liquid displaces another. GEOTEMP2, however, does not attempt to simulate displacement of liquids with a gas or two-phase steam or vice versa. This means that it is not possible to simulate an operation where the type of drilling fluid changes, e.g. mud going to air. GEOTEMP2 was designed primarily for use in predicting the behavior of geothermal wells, but it is flexible enough to handle many typical drilling, production, and injection problems in the oil industry as well. However, GEOTEMP2 does not allow the modeling of gas-filled annuli in production or injection problems. In gas or mist drilling, no radiation losses are included in the energy balance. No attempt is made to model flow in the formation. Average execution time is 50 CP seconds on a CDC CYBER170. This edition of GEOTEMP2 is designated as Version 2.0 by the contributors.Ā«Ā less

  8. Predictive Simulation of Engines

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

    Predictive Simulation of Engines - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management Programs

  9. Lattice Boltzmann Simulation Optimization

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

    Boltzmann Simulation Optimization on Leading Multicore Platforms Selected as Best Paper in Application Track, IPDPS 2008, April 14-28, Miami, Florida, USA Samuel Williams ā€  , Jonathan Carter , Leonid Oliker John Shalf , Katherine Yelick ā€  CRD/NERSC, Lawrence Berkeley National Laboratory Berkeley, CA 94720 ā€  CS Division, University of California at Berkeley, Berkeley, CA 94720 {SWWilliams, JTCarter, LOliker, JShalf, KAYelick}@lbl.gov Abstract We present an auto-tuning approach to optimize

  10. Fast Analysis and Simulation Team | NISAC

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

    SheetsFast Analysis and Simulation Team content top Fast Analysis and Simulation Team

  11. A Reconstructed Discontinuous Galerkin Method for the Compressible Navier-Stokes Equations on Hybrid Grids

    SciTech Connect (OSTI)

    Xiaodong Liu; Lijun Xuan; Hong Luo; Yidong Xia

    2001-01-01

    A reconstructed discontinuous Galerkin (rDG(P1P2)) method, originally introduced for the compressible Euler equations, is developed for the solution of the compressible Navier- Stokes equations on 3D hybrid grids. In this method, a piecewise quadratic polynomial solution is obtained from the underlying piecewise linear DG solution using a hierarchical Weighted Essentially Non-Oscillatory (WENO) reconstruction. The reconstructed quadratic polynomial solution is then used for the computation of the inviscid fluxes and the viscous fluxes using the second formulation of Bassi and Reay (Bassi-Rebay II). The developed rDG(P1P2) method is used to compute a variety of flow problems to assess its accuracy, efficiency, and robustness. The numerical results demonstrate that the rDG(P1P2) method is able to achieve the designed third-order of accuracy at a cost slightly higher than its underlying second-order DG method, outperform the third order DG method in terms of both computing costs and storage requirements, and obtain reliable and accurate solutions to the large eddy simulation (LES) and direct numerical simulation (DNS) of compressible turbulent flows.

  12. Les Houches Guidebook to Monte Carlo generators for hadron collider physics

    SciTech Connect (OSTI)

    Dobbs, M.A

    2004-08-24

    Recently the collider physics community has seen significant advances in the formalisms and implementations of event generators. This review is a primer of the methods commonly used for the simulation of high energy physics events at particle colliders. We provide brief descriptions, references, and links to the specific computer codes which implement the methods. The aim is to provide an overview of the available tools, allowing the reader to ascertain which tool is best for a particular application, but also making clear the limitations of each tool.

  13. Structural Simulation Toolkit. Lunch & Learn

    SciTech Connect (OSTI)

    Moore, Branden J.; Voskuilen, Gwendolyn Renae; Rodrigues, Arun F.; Hammond, Simon David; Hemmert, Karl Scott

    2015-09-01

    This is a presentation outlining a lunch and learn lecture for the Structural Simulation Toolkit, supported by Sandia National Laboratories.

  14. Plasma Simulation Program

    SciTech Connect (OSTI)

    Greenwald, Martin

    2011-10-04

    Many others in the fusion energy and advanced scientific computing communities participated in the development of this plan. The core planning team is grateful for their important contributions. This summary is meant as a quick overview the Fusion Simulation Program's (FSP's) purpose and intentions. There are several additional documents referenced within this one and all are supplemental or flow down from this Program Plan. The overall science goal of the DOE Office of Fusion Energy Sciences (FES) Fusion Simulation Program (FSP) is to develop predictive simulation capability for magnetically confined fusion plasmas at an unprecedented level of integration and fidelity. This will directly support and enable effective U.S. participation in International Thermonuclear Experimental Reactor (ITER) research and the overall mission of delivering practical fusion energy. The FSP will address a rich set of scientific issues together with experimental programs, producing validated integrated physics results. This is very well aligned with the mission of the ITER Organization to coordinate with its members the integrated modeling and control of fusion plasmas, including benchmarking and validation activities. [1]. Initial FSP research will focus on two critical Integrated Science Application (ISA) areas: ISA1, the plasma edge; and ISA2, whole device modeling (WDM) including disruption avoidance. The first of these problems involves the narrow plasma boundary layer and its complex interactions with the plasma core and the surrounding material wall. The second requires development of a computationally tractable, but comprehensive model that describes all equilibrium and dynamic processes at a sufficient level of detail to provide useful prediction of the temporal evolution of fusion plasma experiments. The initial driver for the whole device model will be prediction and avoidance of discharge-terminating disruptions, especially at high performance, which are a critical impediment to successful operation of machines like ITER. If disruptions prove unable to be avoided, their associated dynamics and effects will be addressed in the next phase of the FSP.

  15. Plasma theory and simulation research

    SciTech Connect (OSTI)

    Birdsall, C.K.

    1989-01-01

    Our research group uses both theory and simulation as tools in order to increase the understanding of instabilities, heating, diffusion, transport and other phenomena in plasmas. We also work on the improvement of simulation, both theoretically and practically. Our focus has been more and more on the plasma edge (the sheath''), interactions with boundaries, leading to simulations of whole devices (someday a numerical tokamak).

  16. Bio-threat microparticle simulants

    DOE Patents [OSTI]

    Farquar, George Roy; Leif, Roald N

    2012-10-23

    A bio-threat simulant that includes a carrier and DNA encapsulated in the carrier. Also a method of making a simulant including the steps of providing a carrier and encapsulating DNA in the carrier to produce the bio-threat simulant.

  17. Bio-threat microparticle simulants

    DOE Patents [OSTI]

    Farquar, George Roy; Leif, Roald

    2014-09-16

    A bio-threat simulant that includes a carrier and DNA encapsulated in the carrier. Also a method of making a simulant including the steps of providing a carrier and encapsulating DNA in the carrier to produce the bio-threat simulant.

  18. Distributed Sensors Simulator

    Energy Science and Technology Software Center (OSTI)

    2003-08-30

    The Distributed Sensors Simulator (DSS) is an infrastructure that allows the user to debug and test software for distributed sensor networks without the commitment inherent in using hardware. The flexibility of DSS allows developers and researchers to investigate topological, phenomenological, networking, robustness, and scaling issues; explore arbitrary algorithms for DSNs; and is particularly useful as a proof-of-concept tool. The user provides data on node location and specifications, defines event phenomena, and plugs in the application(s)moreĀ Ā» to run. DSS in turn provides the virtual environmental embedding Ā— but exposed to the user like no true embedding could ever be.Ā«Ā less

  19. Animations/simulations

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

    Numeric data Data plots and fgures Genome/genetics data Interactive data maps Animations/simulations Still images and photos Find scientific research data resulting from DOE-funded research. u u u u u u Find www.osti.gov/dataexplorer Search DOE Data Explorer for Energy and Science Data + Advanced Search DOE/OSTI--C205 01/15 Explore DOE Data Explorer View the most recently added datasets or collections. Browse by titles or subjects. Discover the organizations sponsoring the data. Check out

  20. Fusion Simulation Program

    SciTech Connect (OSTI)

    Project Staff

    2012-02-29

    Under this project, General Atomics (GA) was tasked to develop the experimental validation plans for two high priority ISAs, Boundary and Pedestal and Whole Device Modeling in collaboration with the theory, simulation and experimental communities. The following sections have been incorporated into the final FSP Program Plan (www.pppl.gov/fsp), which was delivered to the US Department of Energy (DOE). Additional deliverables by GA include guidance for validation, development of metrics to evaluate success and procedures for collaboration with experiments. These are also part of the final report.

  1. Animations/simulations

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

    Numeric data Data plots and fgures Genome/genetics data Interactive data maps Animations/simulations Still images and photos Find scientifc research data resulting from DOE-funded research. u u u u u u Find www.osti.gov/dataexplorer Search DOE Data Explorer for Energy and Science Data + Advanced Search DOE/OSTI--C205 02/16 Explore DOE Data Explorer View the most recently added datasets or collections. Browse by titles or subjects. Discover the organizations sponsoring the data. Check out

  2. Confidence in Numerical Simulations

    SciTech Connect (OSTI)

    Hemez, Francois M.

    2015-02-23

    This PowerPoint presentation offers a high-level discussion of uncertainty, confidence and credibility in scientific Modeling and Simulation (M&S). It begins by briefly evoking M&S trends in computational physics and engineering. The first thrust of the discussion is to emphasize that the role of M&S in decision-making is either to support reasoning by similarity or to ā€œforecast,ā€ that is, make predictions about the future or extrapolate to settings or environments that cannot be tested experimentally. The second thrust is to explain that M&S-aided decision-making is an exercise in uncertainty management. The three broad classes of uncertainty in computational physics and engineering are variability and randomness, numerical uncertainty and model-form uncertainty. The last part of the discussion addresses how scientists ā€œthink.ā€ This thought process parallels the scientific method where by a hypothesis is formulated, often accompanied by simplifying assumptions, then, physical experiments and numerical simulations are performed to confirm or reject the hypothesis. ā€œConfidenceā€ derives, not just from the levels of training and experience of analysts, but also from the rigor with which these assessments are performed, documented and peer-reviewed.

  3. Laparoscopic simulation interface

    DOE Patents [OSTI]

    Rosenberg, Louis B.

    2006-04-04

    A method and apparatus for providing high bandwidth and low noise mechanical input and output for computer systems. A gimbal mechanism provides two revolute degrees of freedom to an object about two axes of rotation. A linear axis member is coupled to the gimbal mechanism at the intersection of the two axes of rotation. The linear axis member is capable of being translated along a third axis to provide a third degree of freedom. The user object is coupled to the linear axis member and is thus translatable along the third axis so that the object can be moved along all three degrees of freedom. Transducers associated with the provided degrees of freedom include sensors and actuators and provide an electromechanical interface between the object and a digital processing system. Capstan drive mechanisms transmit forces between the transducers and the object. The linear axis member can also be rotated about its lengthwise axis to provide a fourth degree of freedom, and, optionally, a floating gimbal mechanism is coupled to the linear axis member to provide fifth and sixth degrees of freedom to an object. Transducer sensors are associated with the fourth, fifth, and sixth degrees of freedom. The interface is well suited for simulations of medical procedures and simulations in which an object such as a stylus or a joystick is moved and manipulated by the user.

  4. Energy Simulator Residential Buildings

    Energy Science and Technology Software Center (OSTI)

    1992-02-24

    SERI-RES performs thermal energy analysis of residential or small commercial buildings and has the capability of modeling passive solar equipment such as rock beds, trombe walls, and phase change material. The analysis is accomplished by simulation. A thermal model of the building is created by the user and translated into mathematical form by the program. The mathematical equations are solved repeatedly at time intervals of one hour or less for the period of simulation. ThemoreĀ Ā» mathematical representation of the building is a thermal network with nonlinear, temperature-dependent controls. A combination of forward finite differences, Jacobian iteration, and constrained optimization techniques is used to obtain a solution. An auxiliary interactive editing program, EDITOR, is included for creating building descriptions. EDITOR checks the validity of the input data and also provides facilities for storing and referencing several types of building description files. Some of the data files used by SERI-RES need to be implemented as direct-access files. Programs are included to convert sequential files to direct-access files and vice versa.Ā«Ā less

  5. NII Simulator 1.0

    Energy Science and Technology Software Center (OSTI)

    2009-12-02

    The software listed here is a simulator for SAIC P7500 VACIS non intrusive inspection system. The simulator provides messages similar to those provided by this piece of equipment.To facilitate testing of the Second Line of Defense systems and similar software products from commercial software vendors, this software simulation application has been developed to simulate the P7500 that the Second Line of Defense communications software system must interface with. The primary use of this simulator ismoreĀ Ā» for testing of both Sandia developed and DOE contractor developed software.Ā«Ā less

  6. Transportation Anslysis Simulation System

    Energy Science and Technology Software Center (OSTI)

    2004-08-23

    TRANSIMS version 3.1 is an integrated set of analytical and simulation models and supporting databases. The system is designed to create a virtual metropolitan region with representation of each of the regionĀ’s individuals, their activities and the transportation infrastructure they use. TRANSIMS puts into practice a new, disaggregate approach to travel demand modeling using agent-based micro-simulation technology. TRANSIMS methodology creates a virtual metropolitan region with representation of the transportation infrastructure and the population, at themoreĀ Ā» level of households and individual travelers. Trips a planned to satisfy the populationĀ’s activity pattems at the individual traveler level. TRANSIMS then simulates the movement of travelers and vehicles across the transportation network using multiple modes, including car, transit, bike and walk, on a second-by-second basis. Metropolitan planners must plan growth of their cities according to the stringent transportation system planning requirements of the Interniodal Surface Transportation Efficiency Act of 1991, the Clean Air Act Amendments of 1990 and other similar laws and regulations. These require each state and its metropotitan regions to work together to develop short and long term transportation improvement plans. The plans must (1) estimate the future transportation needs for travelers and goods movements, (2) evaluate ways to manage and reduce congestion, (3) examine the effectiveness of building new roads and transit systems, and (4) limit the environmental impact of the various strategies. The needed consistent and accurate transportation improvement plans require an analytical capability that properly accounts for travel demand, human behavior, traffic and transit operations, major investments, and environmental effects. Other existing planning tools use aggregated information and representative behavior to predict average response and average use of transportation facilities. They do not account for individual traveler response to the dynamic transportation environment. In contrast, TRANSIMS provides disaggregated information that more explicitly represents the complex nature of humans interacting with the transportation system. It first generates a synthetic population that represents individuals and their households in the metropolitan region in a statistically valid way. The demographic makeup and spatial distribution of this synthetic population is derived from census data so that it matches that of the regionĀ’s real population. From survey data, a model is built of household and individual activities that may occur at home, in the workplace, school or shopping centers, for example. Trip plans including departure times, travel modes, and specific routes are created for each individual to get to his or her daily activities. TRANSIMS then simulates the movement of millions of individuals, following their trip plans throughout the transportation network, including their use of vehicles such as cars or buses, on a second-by-second basis. The virtual travel in TRANSIMS mimics the traveling and driving behavior of real people in the metropolitan region. The interactions of individual vehicles produce realistic traffic dynamics from which analysts can judge to performance of the transportation sysime and estimate vehicle emissions. Los Alamos, in cooperation with the Department of Transportation, Federal HIghway Administration and the local Metropolitan Planning Offices, has done TRANSIMS micro-simulations of auto traffic patterns in these two urban areas and completed associated scenario-based studies.Ā«Ā less

  7. Parameterizing correlations between hydrometeor species in mixed-phase Arctic clouds

    SciTech Connect (OSTI)

    Larson, Vincent E.; Nielsen, Brandon J.; Fan, Jiwen; Ovchinnikov, Mikhail

    2011-08-16

    Mixed-phase Arctic clouds, like other clouds, contain small-scale variability in hydrometeor fields, such as cloud water or snow mixing ratio. This variability may be worth parameterizing in coarse-resolution numerical models. In particular, for modeling processes such as accretion and aggregation, it would be useful to parameterize subgrid correlations among hydrometeor species. However, one difficulty is that there exist many hydrometeor species and many microphysical processes, leading to complexity and computational expense.Existing lower and upper bounds (inequalities) on linear correlation coefficients provide useful guidance, but these bounds are too loose to serve directly as a method to predict subgrid correlations. Therefore, this paper proposes an alternative method that is based on a blend of theory and empiricism. The method begins with the spherical parameterization framework of Pinheiro and Bates (1996), which expresses the correlation matrix in terms of its Cholesky factorization. The values of the elements of the Cholesky matrix are parameterized here using a cosine row-wise formula that is inspired by the aforementioned bounds on correlations. The method has three advantages: 1) the computational expense is tolerable; 2) the correlations are, by construction, guaranteed to be consistent with each other; and 3) the methodology is fairly general and hence may be applicable to other problems. The method is tested non-interactively using simulations of three Arctic mixed-phase cloud cases from two different field experiments: the Indirect and Semi-Direct Aerosol Campaign (ISDAC) and the Mixed-Phase Arctic Cloud Experiment (M-PACE). Benchmark simulations are performed using a large-eddy simulation (LES) model that includes a bin microphysical scheme. The correlations estimated by the new method satisfactorily approximate the correlations produced by the LES.

  8. VHDL Control Routing Simulator

    Energy Science and Technology Software Center (OSTI)

    1995-07-10

    The control router simulates a backplane consisting of up to 16 slot. Slot 0, reserved for a control module (cr-ctrl), generates the system clocks and provides the serial interface to the Gating Logic. The remaining 15 slots (1-15) contain routing modules (cr mod), each having up to 64 serial inputs and outputs with FIFOs. Messages to be transmitted to the Control Router are taken from text files. There are currently 17 such source files. InmoreĀ Ā» the model, the serial output of each source is connected to multiple receivers, so that there are 8 identical messages transmitted to the router for each message file entry.Ā«Ā less

  9. Non-detonable explosive simulators

    DOE Patents [OSTI]

    Simpson, R.L.; Pruneda, C.O.

    1994-11-01

    A simulator which is chemically equivalent to an explosive, but is not detonable. The simulator has particular use in the training of explosives detecting dogs and calibrating sensitive analytical instruments. The explosive simulants may be fabricated by different techniques, a first involves the use of standard slurry coatings to produce a material with a very high binder to explosive ratio without masking the explosive vapor, and the second involves coating inert beads with thin layers of explosive molecules. 5 figs.

  10. Non-detonable explosive simulators

    DOE Patents [OSTI]

    Simpson, Randall L. (Livermore, CA); Pruneda, Cesar O. (Livermore, CA)

    1994-01-01

    A simulator which is chemically equivalent to an explosive, but is not detonable. The simulator has particular use in the training of explosives detecting dogs and calibrating sensitive analytical instruments. The explosive simulants may be fabricated by different techniques, a first involves the use of standard slurry coatings to produce a material with a very high binder to explosive ratio without masking the explosive vapor, and the second involves coating inert beads with thin layers of explosive molecules.

  11. The promise of quantum simulation

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

    Muller, Richard P.; Blume-Kohout, Robin

    2015-07-21

    In this study, quantum simulations promise to be one of the primary applications of quantum computers, should one be constructed. This article briefly summarizes the history of quantum simulation in light of the recent result of Wang and co-workers, demonstrating calculation of the ground and excited states for a HeH+ molecule, and concludes with a discussion of why this and other recent progress in the field suggest that quantum simulations of quantum chemistry have a bright future.

  12. Parallel Power Grid Simulation Toolkit

    Energy Science and Technology Software Center (OSTI)

    2015-09-14

    ParGrid is a 'wrapper' that integrates a coupled Power Grid Simulation toolkit consisting of a library to manage the synchronization and communication of independent simulations. The included library code in ParGid, named FSKIT, is intended to support the coupling multiple continuous and discrete even parallel simulations. The code is designed using modern object oriented C++ methods utilizing C++11 and current Boost libraries to ensure compatibility with multiple operating systems and environments.

  13. Lubricant characterization by molecular simulation

    SciTech Connect (OSTI)

    Moore, J.D.; Cui, S.T.; Cummings, P.T.; Cochran, H.D.

    1997-12-01

    The authors have reported the calculation of the kinematic viscosity index of squalane from nonequilibrium molecular dynamics simulations. This represents the first accurate quantitative prediction of this measure of lubricant performance by molecular simulation. Using the same general alkane potential model, this computational approach offers the possibility of predicting the performance of potential lubricants prior to synthesis. Consequently, molecular simulation is poised to become an important tool for future lubricant development.

  14. BERNAS ION SOURCE DISCHARGE SIMULATION

    SciTech Connect (OSTI)

    RUDSKOY,I.; KULEVOY, T.V.; PETRENKO, S.V.; KUIBEDA, R.P.; SELEZNEV, D.N.; PERSHIN, V.I.; HERSHCOVITCH, A.; JOHNSON, B.M.; GUSHENETS, V.I.; OKS, E.M.; POOLE, H.J.

    2007-08-26

    The joint research and development program is continued to develop steady-state ion source of decaborane beam for ion implantation industry. Bemas ion source is the wide used ion source for ion implantation industry. The new simulation code was developed for the Bemas ion source discharge simulation. We present first results of the simulation for several materials interested in semiconductors. As well the comparison of results obtained with experimental data obtained at the ITEP ion source test-bench is presented.

  15. Power Plant Modeling and Simulation

    ScienceCinema (OSTI)

    None

    2010-01-08

    The National Energy Technology Laboratory's Office of Research and Development provides open source tools and expetise for modeling and simulating power plants and carbon sequestration technologies.

  16. EERE Energy Simulation Games Lesson

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

    the following two questions. Did you learn anything interesting about any of the energy technologies that you used during the simulations? Were there factors (pros or...

  17. Power Plant Modeling and Simulation

    SciTech Connect (OSTI)

    2008-07-21

    The National Energy Technology Laboratory's Office of Research and Development provides open source tools and expetise for modeling and simulating power plants and carbon sequestration technologies.

  18. simulations | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    simulations | National Nuclear Security Administration Facebook Twitter Youtube Flickr RSS People Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy...

  19. Watts Bar Operating Cycles Simulated...

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

    Coming in our next issue of Tech Notes: Fuel Performance Predictions with VERA Watts Bar Operating Cycles Simulated to Present Among the most important accomplishments during CASL...

  20. Distributed Energy Technology Simulator: Microturbine Demonstration...

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

    Simulator: Microturbine Demonstration, October 2001 Distributed Energy Technology Simulator: Microturbine Demonstration, October 2001 This 2001 paper discusses the National Rural ...

  1. Multidimensional simulation and chemical kinetics development...

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

    Multidimensional simulation and chemical kinetics development for high efficiency clean combustion engines Multidimensional simulation and chemical kinetics development for high...

  2. Nonequilibrium molecular dynamics simulations of confined fluids...

    Office of Scientific and Technical Information (OSTI)

    ... SIMULATION; RHEOLOGY; GOLD; SHEAR; PRESSURE DEPENDENCE; SPATIAL DISTRIBUTION; LUBRICANTS DECANE; COMPUTERIZED SIMULATION; RHEOLOGY; GOLD; COMPRESSION; SHEAR; PRESSURE ...

  3. The selection of turbulence models for prediction of room airflow

    SciTech Connect (OSTI)

    Nielsen, P.V.

    1998-10-01

    The airflow in buildings involves a combination of many different flow elements. It is, therefore, difficult to find an adequate, all-round turbulence model covering all aspects. Consequently, it is appropriate and economical to choose turbulence models according to the situation that is to be predicted. This paper discusses the use of different turbulence models and their advantages in given situations. As an example, it is shown that a simple zero-equation model can be used for the prediction of special situations as flow with a low level of turbulence. A zero-equation model with compensation for room dimensions and velocity level also is discussed. A {kappa}-{epsilon} model expanded by damping functions is used to improve the prediction of the flow in a room ventilated by displacement ventilation. The damping functions especially take into account the turbulence level and the vertical temperature gradient. Low Reynolds number models (LNR models) are used to improve the prediction of evaporation-controlled emissions from building material, which is shown by an example. Finally, large eddy simulation (LES) of room airflow is discussed and demonstrated.

  4. Fading channel simulator

    DOE Patents [OSTI]

    Argo, Paul E. (Los Alamos, NM); Fitzgerald, T. Joseph (Los Alamos, NM)

    1993-01-01

    Fading channel effects on a transmitted communication signal are simulated with both frequency and time variations using a channel scattering function to affect the transmitted signal. A conventional channel scattering function is converted to a series of channel realizations by multiplying the square root of the channel scattering function by a complex number of which the real and imaginary parts are each independent variables. The two-dimensional inverse-FFT of this complex-valued channel realization yields a matrix of channel coefficients that provide a complete frequency-time description of the channel. The transmitted radio signal is segmented to provide a series of transmitted signal and each segment is subject to FFT to generate a series of signal coefficient matrices. The channel coefficient matrices and signal coefficient matrices are then multiplied and subjected to inverse-FFT to output a signal representing the received affected radio signal. A variety of channel scattering functions can be used to characterize the response of a transmitter-receiver system to such atmospheric effects.

  5. Electricity Portfolio Simulation Model

    Energy Science and Technology Software Center (OSTI)

    2005-09-01

    Stakeholders often have competing interests when selecting or planning new power plants. The purpose of developing this preliminary Electricity Portfolio Simulation Model (EPSim) is to provide a first cut, dynamic methodology and approach to this problem, that can subsequently be refined and validated, that may help energy planners, policy makers, and energy students better understand the tradeoffs associated with competing electricity portfolios. EPSim allows the user to explore competing electricity portfolios annually from 2002 tomoreĀ Ā» 2025 in terms of five different criteria: cost, environmental impacts, energy dependence, health and safety, and sustainability. Four additional criteria (infrastructure vulnerability, service limitations, policy needs and science and technology needs) may be added in future versions of the model. Using an analytic hierarchy process (AHP) approach, users or groups of users apply weights to each of the criteria. The default energy assumptions of the model mimic Department of EnergyĀ’s (DOE) electricity portfolio to 2025 (EIA, 2005). At any time, the user can compare alternative portfolios to this reference case portfolio.Ā«Ā less

  6. S-SEED Simulator

    Energy Science and Technology Software Center (OSTI)

    2008-11-21

    This code simulates the transient response of two self-electrooptic-effect devices (SEEDs) connected in series to form an S-SEED pair as used in all-optical high-speed switching. Both optical beam propagation and carrier motion is assumed to be normal to the epi plane, so the code is inherently 1D in nature. For each SEED, an optical input in W/cm**2 is specified as a function of time (usually a step function input). The signal is absorbed during amoreĀ Ā» double pass through the intrinsic region, with a spatially-dependent absorption coefficient that is dependent on the transient local electric field. This absorption generates electron-hole pairs that then contribute to the device current, and a transient optical output is predicted. Carriers in the semiconductor layers are generated through thermal excitation or optical absorption, move under the action of diffusion and self-consistent electric fields updated at each time step by a 1D Poisson solver, and recombine at density-dependent rates. The different epi layers are independently specified by position, thickness, doping type and density, and thus space charge effects and junction capacitance are included automatically.Ā«Ā less

  7. Cantera Aerosol Dynamics Simulator

    Energy Science and Technology Software Center (OSTI)

    2004-09-01

    The Cantera Aerosol Dynamics Simulator (CADS) package is a general library for aerosol modeling to address aerosol general dynamics, including formation from gas phase reactions, surface chemistry (growth and oxidation), bulk particle chemistry, transport by Brownian diffusion, thermophoresis, and diffusiophoresis with linkage to DSMC studies, and thermal radiative transport. The library is based upon Cantera, a C++ Cal Tech code that handles gas phase species transport, reaction, and thermodynamics. The method uses a discontinuous galerkinmoreĀ Ā» formulation for the condensation and coagulation operator that conserves particles, elements, and enthalpy up to round-off error. Both O-D and 1-D time dependent applications have been developed with the library. Multiple species in the solid phase are handled as well. The O-D application, called Tdcads (Time Dependent CADS) is distributed with the library. Tdcads can address both constant volume and constant pressure adiabatic homogeneous problems. An extensive set of sample problems for Tdcads is also provided.Ā«Ā less

  8. Coal Preparation Plant Simulation

    Energy Science and Technology Software Center (OSTI)

    1992-02-25

    COALPREP assesses the degree of cleaning obtained with different coal feeds for a given plant configuration and mode of operation. It allows the user to simulate coal preparation plants to determine an optimum plant configuration for a given degree of cleaning. The user can compare the performance of alternative plant configurations as well as determine the impact of various modes of operation for a proposed configuration. The devices that can be modelled include froth flotationmoreĀ Ā» devices, washers, dewatering equipment, thermal dryers, rotary breakers, roll crushers, classifiers, screens, blenders and splitters, and gravity thickeners. The user must specify the plant configuration and operating conditions and a description of the coal feed. COALPREP then determines the flowrates within the plant and a description of each flow stream (i.e. the weight distribution, percent ash, pyritic sulfur and total sulfur, moisture, BTU content, recoveries, and specific gravity of separation). COALPREP also includes a capability for calculating the cleaning cost per ton of coal. The IBM PC version contains two auxiliary programs, DATAPREP and FORLIST. DATAPREP is an interactive preprocessor for creating and editing COALPREP input data. FORLIST converts carriage-control characters in FORTRAN output data to ASCII line-feed (X''0A'') characters.Ā«Ā less

  9. Coal Preparation Plant Simulation

    Energy Science and Technology Software Center (OSTI)

    1992-02-25

    COALPREP assesses the degree of cleaning obtained with different coal feeds for a given plant configuration and mode of operation. It allows the user to simulate coal preparation plants to determine an optimum plant configuration for a given degree of cleaning. The user can compare the performance of alternative plant configurations as well as determine the impact of various modes of operation for a proposed configuration. The devices that can be modelled include froth flotationmoreĀ Ā» devices, washers, dewatering equipment, thermal dryers, rotary breakers, roll crushers, classifiers, screens, blenders and splitters, and gravity thickeners. The user must specify the plant configuration and operating conditions and a description of the coal feed. COALPREP then determines the flowrates within the plant and a description of each flow stream (i.e. the weight distribution, percent ash, pyritic sulfur and total sulfur, moisture, BTU content, recoveries, and specific gravity of separation). COALPREP also includes a capability for calculating the cleaning cost per ton of coal.Ā«Ā less

  10. A stochastic extension of the explicit algebraic subgrid-scale models

    SciTech Connect (OSTI)

    Rasam, A. Brethouwer, G.; Johansson, A. V.

    2014-05-15

    The explicit algebraic subgrid-scale (SGS) stress model (EASM) of Marstorp et al. [“Explicit algebraic subgrid stress models with application to rotating channel flow,” J. Fluid Mech. 639, 403–432 (2009)] and explicit algebraic SGS scalar flux model (EASFM) of Rasam et al. [“An explicit algebraic model for the subgrid-scale passive scalar flux,” J. Fluid Mech. 721, 541–577 (2013)] are extended with stochastic terms based on the Langevin equation formalism for the subgrid-scales by Marstorp et al. [“A stochastic subgrid model with application to turbulent flow and scalar mixing,” Phys. Fluids 19, 035107 (2007)]. The EASM and EASFM are nonlinear mixed and tensor eddy-diffusivity models, which improve large eddy simulation (LES) predictions of the mean flow, Reynolds stresses, and scalar fluxes of wall-bounded flows compared to isotropic eddy-viscosity and eddy-diffusivity SGS models, especially at coarse resolutions. The purpose of the stochastic extension of the explicit algebraic SGS models is to further improve the characteristics of the kinetic energy and scalar variance SGS dissipation, which are key quantities that govern the small-scale mixing and dispersion dynamics. LES of turbulent channel flow with passive scalar transport shows that the stochastic terms enhance SGS dissipation statistics such as length scale, variance, and probability density functions and introduce a significant amount of backscatter of energy from the subgrid to the resolved scales without causing numerical stability problems. The improvements in the SGS dissipation predictions in turn enhances the predicted resolved statistics such as the mean scalar, scalar fluxes, Reynolds stresses, and correlation lengths. Moreover, the nonalignment between the SGS stress and resolved strain-rate tensors predicted by the EASM with stochastic extension is in much closer agreement with direct numerical simulation data.

  11. Offshore Wind Farm Model Development - Upcoming Release of the University

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

    of Minnesota's Virtual Wind Simulator | Department of Energy Offshore Wind Farm Model Development - Upcoming Release of the University of Minnesota's Virtual Wind Simulator Offshore Wind Farm Model Development - Upcoming Release of the University of Minnesota's Virtual Wind Simulator September 16, 2015 - 1:14pm Addthis Large-eddy simulation of wind farms with parameterization of wind turbines is emerging as a powerful tool for improving the performance and lowering the maintenance cost of

  12. Terascale Simulation Tolls and Technologies

    Energy Science and Technology Software Center (OSTI)

    2006-11-01

    The Terascale Simulation Tools and Technologies (TSTT) center is a collaboration between several universities and DOE laboratories, and is funded by the DOE Scientific Discovery for Advanced Computing (SciDAC) program. The primary objective of the (TSTT) center is to develop technologies taht enable application scientists to easily use multiple mesh and discretization strageties within a single simulation on terascale computeres. This is accomplished through the development of common functional interfaces to geometry, mesh, and othermoreĀ Ā» simulation data. This package is Sandia's implementation of these interfaces.Ā«Ā less

  13. The Xygra gun simulation tool.

    SciTech Connect (OSTI)

    Garasi, Christopher Joseph; Lamppa, Derek C.; Aubuchon, Matthew S.; Shirley, David Noyes; Robinson, Allen Conrad; Russo, Thomas V.

    2008-12-01

    Inductive electromagnetic launchers, or coilguns, use discrete solenoidal coils to accelerate a coaxial conductive armature. To date, Sandia has been using an internally developed code, SLINGSHOT, as a point-mass lumped circuit element simulation tool for modeling coilgun behavior for design and verification purposes. This code has shortcomings in terms of accurately modeling gun performance under stressful electromagnetic propulsion environments. To correct for these limitations, it was decided to attempt to closely couple two Sandia simulation codes, Xyce and ALEGRA, to develop a more rigorous simulation capability for demanding launch applications. This report summarizes the modifications made to each respective code and the path forward to completing interfacing between them.

  14. Simulating Afterburn with LLNL Hydrocodes

    SciTech Connect (OSTI)

    Daily, L D

    2004-06-11

    Presented here is a working methodology for adapting a Lawrence Livermore National Laboratory (LLNL) developed hydrocode, ALE3D, to simulate weapon damage effects when afterburn is a consideration in the blast propagation. Experiments have shown that afterburn is of great consequence in enclosed environments (i.e. bomb in tunnel scenario, penetrating conventional munition in a bunker, or satchel charge placed in a deep underground facility). This empirical energy deposition methodology simulates the anticipated addition of kinetic energy that has been demonstrated by experiment (Kuhl, et. al. 1998), without explicitly solving the chemistry, or resolving the mesh to capture small-scale vorticity. This effort is intended to complement the existing capability of either coupling ALE3D blast simulations with DYNA3D or performing fully coupled ALE3D simulations to predict building or component failure, for applications in National Security offensive strike planning as well as Homeland Defense infrastructure protection.

  15. Dynamic Simulation Nuclear Power Plants

    Energy Science and Technology Software Center (OSTI)

    1992-03-03

    DSNP (Dynamic Simulator for Nuclear Power-Plants) is a system of programs and data files by which a nuclear power plant, or part thereof, can be simulated. The acronym DSNP is used interchangeably for the DSNP language, the DSNP libraries, the DSNP precompiler, and the DSNP document generator. The DSNP language is a special-purpose, block-oriented, digital-simulation language developed to facilitate the preparation of dynamic simulations of a large variety of nuclear power plants. It is amoreĀ Ā» user-oriented language that permits the user to prepare simulation programs directly from power plant block diagrams and flow charts by recognizing the symbolic DSNP statements for the appropriate physical components and listing these statements in a logical sequence according to the flow of physical properties in the simulated power plant. Physical components of nuclear power plants are represented by functional blocks, or modules. Many of the more complex components are represented by several modules. The nuclear reactor, for example, has a kinetic module, a power distribution module, a feedback module, a thermodynamic module, a hydraulic module, and a radioactive heat decay module. These modules are stored in DSNP libraries in the form of a DSNP subroutine or function, a block of statements, a macro, or a combination of the above. Basic functional blocks such as integrators, pipes, function generators, connectors, and many auxiliary functions representing properties of materials used in nuclear power plants are also available. The DSNP precompiler analyzes the DSNP simulation program, performs the appropriate translations, inserts the requested modules from the library, links these modules together, searches necessary data files, and produces a simulation program in FORTRAN.Ā«Ā less

  16. Predictive Simulation | Department of Energy

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

    Predictive Simulation Predictive Simulation Empirical To First Principle Models Computing tools currently used in nuclear industry and regulatory practice are based primarily on empirical math models to approximate, or fit, existing experimental data. Many have a pedigree reaching back to the 1970s and 1980s and were designed to support decision making and evaluate everything from behavior of individual fuel pellets to severe accident scenarios for an entire power plant. Programs like SAPHIRE,

  17. Simulation and Non-Simulation Based Human Reliability Analysis Approaches

    SciTech Connect (OSTI)

    Boring, Ronald Laurids; Shirley, Rachel Elizabeth; Joe, Jeffrey Clark; Mandelli, Diego

    2014-12-01

    Part of the U.S. Department of Energy’s Light Water Reactor Sustainability (LWRS) Program, the Risk-Informed Safety Margin Characterization (RISMC) Pathway develops approaches to estimating and managing safety margins. RISMC simulations pair deterministic plant physics models with probabilistic risk models. As human interactions are an essential element of plant risk, it is necessary to integrate human actions into the RISMC risk model. In this report, we review simulation-based and non-simulation-based human reliability assessment (HRA) methods. Chapter 2 surveys non-simulation-based HRA methods. Conventional HRA methods target static Probabilistic Risk Assessments for Level 1 events. These methods would require significant modification for use in dynamic simulation of Level 2 and Level 3 events. Chapter 3 is a review of human performance models. A variety of methods and models simulate dynamic human performance; however, most of these human performance models were developed outside the risk domain and have not been used for HRA. The exception is the ADS-IDAC model, which can be thought of as a virtual operator program. This model is resource-intensive but provides a detailed model of every operator action in a given scenario, along with models of numerous factors that can influence operator performance. Finally, Chapter 4 reviews the treatment of timing of operator actions in HRA methods. This chapter is an example of one of the critical gaps between existing HRA methods and the needs of dynamic HRA. This report summarizes the foundational information needed to develop a feasible approach to modeling human interactions in the RISMC simulations.

  18. Clot Busting Simulations Test Potential Stroke Treatment

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

    Clot Busting Simulations Test Potential Stroke Treatment Clot Busting Simulations Test Potential Stroke Treatment September 24, 2013 Contact: Linda Vu, +1 510 495 2402, lvu@lbl.gov ...

  19. Energy Choice Simulator | Open Energy Information

    Open Energy Info (EERE)

    Choice Simulator Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Energy Choice Simulator AgencyCompany Organization: Great Plains Institute Sector: Energy Focus Area:...

  20. First trillion particle cosmological simulation completed

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

    public data release. A paper describes the research and data release. Significance of the research The Dark Sky Simulations are an ongoing series of cosmological simulations...

  1. Climate Change Simulations with CCSM & CESM

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

    Climate Change Simulations with CCSM & CESM Climate Change Simulations with CCSM & CESM Key Challenges: Perform fundamental research on the processes that influence the natural...

  2. Zero Power Reactor simulation | Argonne National Laboratory

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

    Zero Power Reactor simulation Share Description Ever wanted to see a nuclear reactor core in action? Here's a detailed simulation of the Zero Power Reactor experiment, run by...

  3. Vehicle & Systems Simulation & Testing | Department of Energy

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

    & Systems Simulation & Testing Vehicle & Systems Simulation & Testing 2011 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer...

  4. Dynamics of Molecular Clouds: Observations, Simulations, and...

    Office of Scientific and Technical Information (OSTI)

    Simulations, and NIF Experiments Citation Details In-Document Search Title: Dynamics of Molecular Clouds: Observations, Simulations, and NIF Experiments Authors: Kane, J ...

  5. ARM - Publications: Science Team Meeting Documents

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

    Sky Cover and Cloud Fraction Kassianov, E., Long, C., and Ovtchinnikov, M., Pacific Northwest National Laboratory Fourteenth Atmospheric Radiation Measurement (ARM) Science Team Meeting Previously (Kassianov et al., 2002), we examined the relationship between hemispherical sky cover and nadir-view cloud fraction by using model simulations. These simulations of ground-based hemispherical measurements were based on four-dimensional cloud fields produced by a large eddy simulation model. In

  6. TOPAS Tool for Particle Simulation

    Energy Science and Technology Software Center (OSTI)

    2013-05-30

    TOPAS lets users simulate the passage of subatomic particles moving through any kind of radiation therapy treatment system, can import a patient geometry, can record dose and other quantities, has advanced graphics, and is fully four-dimensional (3D plus time) to handle the most challenging time-dependent aspects of modern cancer treatments.TOPAS unlocks the power of the most accurate particle transport simulation technique, the Monte Carlo (MC) method, while removing the painstaking coding work such methods usedmoreĀ Ā» to require. Research physicists can use TOPAS to improve delivery systems towards safer and more effective radiation therapy treatments, easily setting up and running complex simulations that previously used to take months of preparation. Clinical physicists can use TOPAS to increase accuracy while reducing side effects, simulating patient-specific treatment plans at the touch of a button. TOPAS is designed as a Ā“user codeĀ” layered on top of the Geant4 Simulation Toolkit. TOPAS includes the standard Geant4 toolkit, plus additional code to make Geant4 easier to control and to extend Geant4 functionality. TOPAS aims to make proton simulation both Ā“reliableĀ” and Ā“repeatable.Ā” Ā“ReliableĀ” means both accurate physics and a high likelihood to simulate precisely what the user intended to simulate, reducing issues of wrong units, wrong materials, wrong scoring locations, etc. Ā“RepeatableĀ” means not just getting the same result from one simulation to another, but being able to easily restore a previously used setup and reducing sources of error when a setup is passed from one user to another. TOPAS control system incorporates key lessons from safety management, proactively removing possible sources of user error such as line-ordering mistakes In control files. TOPAS has been used to model proton therapy treatment examples including the UCSF eye treatment head, the MGH stereotactic alignment in radiosurgery treatment head and the MGH gantry treatment heads in passive scattering and scanning modes, and has demonstrated dose calculation based on patient-specific CT data.Ā«Ā less

  7. Visual Interface for Materials Simulations

    Energy Science and Technology Software Center (OSTI)

    2004-08-01

    VIMES (Visual Inteface for Materials Simulations) is a graphical user interface (GUI) for pre- and post-processing alomistic materials science calculations. The code includes tools for building and visualizing simple crystals, supercells, and surfaces, as well as tools for managing and modifying the input to Sandia materials simulations codes such as Quest (Peter Schultz, SNL 9235) and Towhee (Marcus Martin, SNL 9235). It is often useful to have a graphical interlace to construct input for materialsmoreĀ Ā» simulations codes and to analyze the output of these programs. VIMES has been designed not only to build and visualize different materials systems, but also to allow several Sandia codes to be easier to use and analyze. Furthermore. VIMES has been designed to be reasonably easy to extend to new materials programs. We anticipate that users of Sandia materials simulations codes will use VIMCS to simplify the submission and analysis of these simulations. VIMES uses standard OpenGL graphics (as implemented in the Python programming language) to display the molecules. The algorithms used to rotate, zoom, and pan molecules are all standard applications using the OpenGL libraries. VIMES uses the Marching Cubes algorithm for isosurfacing 3D data such as molecular orbitals or electron densities around the molecules.Ā«Ā less

  8. Mesoscale Simulations of Power Compaction

    SciTech Connect (OSTI)

    Lomov, I; Fujino, D; Antoun, T; Liu, B

    2009-08-06

    Mesoscale 3D simulations of metal and ceramic powder compaction in shock waves have been performed with an Eulerian hydrocode GEODYN. The approach was validated by simulating shock compaction of porous well-characterized ductile metal using Steinberg material model. Results of the simulations with handbook values for parameters of solid 2024 aluminum have good agreement with experimental compaction curves and wave profiles. Brittle ceramic materials are not so well studied as metals, so material model for ceramic (tungsten carbide) has been fitted to shock compression experiments of non-porous samples and further calibrated to match experimental compaction curves. Direct simulations of gas gun experiments with ceramic powder have been performed and showed good agreement with experimental data. Numerical shock wave profile has same character and thickness as measured with VISAR. Numerical results show reshock states above the single-shock Hugoniot line also observed in experiments. They found that to receive good quantitative agreement with experiment it is essential to perform 3D simulations.

  9. The DOE Atmospheric Radia4on Measurement Program's LES ARM Symbio4c Simula4on and Observa4on (LASSO) Workflow

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

    DOE Atmospheric Radia4on Measurement Program's LES ARM Symbio4c Simula4on and Observa4on (LASSO) Workflow Ini4aliza4on, Forcing and Mul4scale Data Assimila4on Zhijin Li JPL and UCLA Coauthors: Xiaoping Cheng (UCLA), William I. Gustafson Jr. and Heng Xiao (PNNL), Andrew Vogelmann, Satoshi Endo and Tami Toto (BNL) AGU Fall Mee*ng 2015, San Francisco, CA, December 14, 2015 The Atmospheric Radia4on Measurement (ARM) Facility for Integra4ng Modeling with Observa4ons Dense observa4ons are coupled with

  10. Special nuclear material simulation device

    DOE Patents [OSTI]

    Leckey, John H.; DeMint, Amy; Gooch, Jack; Hawk, Todd; Pickett, Chris A.; Blessinger, Chris; York, Robbie L.

    2014-08-12

    An apparatus for simulating special nuclear material is provided. The apparatus typically contains a small quantity of special nuclear material (SNM) in a configuration that simulates a much larger quantity of SNM. Generally the apparatus includes a spherical shell that is formed from an alloy containing a small quantity of highly enriched uranium. Also typically provided is a core of depleted uranium. A spacer, typically aluminum, may be used to separate the depleted uranium from the shell of uranium alloy. A cladding, typically made of titanium, is provided to seal the source. Methods are provided to simulate SNM for testing radiation monitoring portals. Typically the methods use at least one primary SNM spectral line and exclude at least one secondary SNM spectral line.

  11. Lattice Simulations and Infrared Conformality

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

    Appelquist, Thomas; Fleming, George T.; Lin, Meifeng; Neil, Ethan T.; Schaich, David A

    2011-09-01

    We examine several recent lattice-simulation data sets, asking whether they are consistent with infrared conformality. We observe, in particular, that for an SU(3) gauge theory with 12 Dirac fermions in the fundamental representation, recent simulation data can be described assuming infrared conformality. Lattice simulations include a fermion mass m which is then extrapolated to zero, and we note that this data can be fit by a small-m expansion, allowing a controlled extrapolation. We also note that the conformal hypothesis does not work well for two theories that are known or expected to be confining and chirally broken, and that itmoreĀ Ā» does work well for another theory expected to be infrared conformal.Ā«Ā less

  12. simulators | netl.doe.gov

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

    simulators DOE/BC-89/3/SP. Handbook for Personal Computer Version of BOAST II: A Three- Dimensional, Three-Phase Black Oil Applied Simulation Tool. Bartlesville Project Office. January 1989. 82 pp. NTIS Order No. DE89000725. FORTRAN source code and executable program. Min. Req.: IBM PC/AT, PS-2, or compatible computer with 640 Kbytes of memory. Download 464 KB Manual 75 KB Manual 404 KB Reference paper (1033-3,v1) by Fanchi, et al. Manual 83 KB Reference paper (1033-3,v2) by Fanchi, et al. BOAST

  13. MOOSE: Multiphysics Object-Oriented Simulation Environment

    ScienceCinema (OSTI)

    Gaston, Derek

    2014-05-30

    An overview of Idaho National Laboratory's MOOSE: Multiphysics Object-Oriented Simulation Environment

  14. Microgrid and Inverter Control and Simulator Software

    SciTech Connect (OSTI)

    2012-09-13

    A collection of software that can simulate the operation of an inverter on a microgrid or control a real inverter. In addition, it can simulate the control of multiple nodes on a microgrid." Application: Simulation of inverters and microgrids; control of inverters on microgrids." The MMI submodule is designed to control custom inverter hardware, and to simulate that hardware. The INVERTER submodule is only the simulator code, and is of an earlier generation than the simulator in MMI. The MICROGRID submodule is an agent-based simulator of multiple nodes on a microgrid which presents a web interface. The WIND submodule produces movies of wind data with a web interface.

  15. TaqMan PCR Simulator

    Energy Science and Technology Software Center (OSTI)

    2007-05-01

    TaqSim simulates various types of PRC reactions, including multiplex reactions. Given a set of primers and dearch databases, TaqSim identifies amplicons that match user defined criteria and can generate output files in a number of formats allowing it to serve as a front-end or back-end for other software.

  16. Solar Hot Water Hourly Simulation

    Energy Science and Technology Software Center (OSTI)

    2009-12-31

    The Software consists of a spreadsheet written in Microsoft Excel which provides an hourly simulation of a solar hot water heating system (including solar geometry, solar collector efficiency as a function of temperature, energy balance on storage tank and lifecycle cost analysis).

  17. Xyce parallel electronic simulator design.

    SciTech Connect (OSTI)

    Thornquist, Heidi K.; Rankin, Eric Lamont; Mei, Ting; Schiek, Richard Louis; Keiter, Eric Richard; Russo, Thomas V.

    2010-09-01

    This document is the Xyce Circuit Simulator developer guide. Xyce has been designed from the 'ground up' to be a SPICE-compatible, distributed memory parallel circuit simulator. While it is in many respects a research code, Xyce is intended to be a production simulator. As such, having software quality engineering (SQE) procedures in place to insure a high level of code quality and robustness are essential. Version control, issue tracking customer support, C++ style guildlines and the Xyce release process are all described. The Xyce Parallel Electronic Simulator has been under development at Sandia since 1999. Historically, Xyce has mostly been funded by ASC, the original focus of Xyce development has primarily been related to circuits for nuclear weapons. However, this has not been the only focus and it is expected that the project will diversify. Like many ASC projects, Xyce is a group development effort, which involves a number of researchers, engineers, scientists, mathmaticians and computer scientists. In addition to diversity of background, it is to be expected on long term projects for there to be a certain amount of staff turnover, as people move on to different projects. As a result, it is very important that the project maintain high software quality standards. The point of this document is to formally document a number of the software quality practices followed by the Xyce team in one place. Also, it is hoped that this document will be a good source of information for new developers.

  18. Fission Particle Emission Multiplicity Simulation

    Energy Science and Technology Software Center (OSTI)

    2006-09-27

    Simulates discrete neutron and gamma-ray emission from the fission of heavy nuclei that is either spontaneous or neutron induced. This is a function library that encapsulates the fission physics and is intended to be called Monte Carlo transport code.

  19. First trillion particle cosmological simulation completed

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

    First trillion particle cosmological simulation completed First trillion particle cosmological simulation completed A team of astrophysicists and computer scientists has created high-resolution cyber images of our cosmos. January 8, 2015 Simulation of the cosmic web of the dark matter mass distribution. This region represents about 1/10,000 of the total simulation volume. Simulation of the cosmic web of the dark matter mass distribution. This region represents about 1/10,000 of the total

  20. TASK 2: QUENCH ZONE SIMULATION

    SciTech Connect (OSTI)

    Fusselman, Steve

    2015-09-30

    Aerojet Rocketdyne (AR) has developed an innovative gasifier concept incorporating advanced technologies in ultra-dense phase dry feed system, rapid mix injector, and advanced component cooling to significantly improve gasifier performance, life, and cost compared to commercially available state-of-the-art systems. A key feature of the AR gasifier design is the transition from the gasifier outlet into the quench zone, where the raw syngas is cooled to ~ 400Ā°C by injection and vaporization of atomized water. Earlier pilot plant testing revealed a propensity for the original gasifier outlet design to accumulate slag in the outlet, leading to erratic syngas flow from the outlet. Subsequent design modifications successfully resolved this issue in the pilot plant gasifier. In order to gain greater insight into the physical phenomena occurring within this zone, AR developed a cold flow simulation apparatus with Coanda Research & Development with a high degree of similitude to hot fire conditions with the pilot scale gasifier design, and capable of accommodating a scaled-down quench zone for a demonstration-scale gasifier. The objective of this task was to validate similitude of the cold flow simulation model by comparison of pilot-scale outlet design performance, and to assess demonstration scale gasifier design feasibility from testing of a scaled-down outlet design. Test results did exhibit a strong correspondence with the two pilot scale outlet designs, indicating credible similitude for the cold flow simulation device. Testing of the scaled-down outlet revealed important considerations in the design and operation of the demonstration scale gasifier, in particular pertaining to the relative momentum between the downcoming raw syngas and the sprayed quench water and associated impacts on flow patterns within the quench zone. This report describes key findings from the test program, including assessment of pilot plant configuration simulations relative to actual results on the pilot plant gasifier and demonstration plant design recommendations, based on cold flow simulation results.

  1. A multiscale MDCT image-based breathing lung model with time-varying regional ventilation

    SciTech Connect (OSTI)

    Yin, Youbing, E-mail: youbing-yin@uiowa.edu [Department of Mechanical and Industrial Engineering, The University of Iowa, Iowa City, IA 52242 (United States) [Department of Mechanical and Industrial Engineering, The University of Iowa, Iowa City, IA 52242 (United States); IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA 52242 (United States); Department of Radiology, The University of Iowa, Iowa City, IA 52242 (United States); Choi, Jiwoong, E-mail: jiwoong-choi@uiowa.edu [Department of Mechanical and Industrial Engineering, The University of Iowa, Iowa City, IA 52242 (United States) [Department of Mechanical and Industrial Engineering, The University of Iowa, Iowa City, IA 52242 (United States); IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA 52242 (United States); Hoffman, Eric A., E-mail: eric-hoffman@uiowa.edu [Department of Radiology, The University of Iowa, Iowa City, IA 52242 (United States); Department of Biomedical Engineering, The University of Iowa, Iowa City, IA 52242 (United States); Department of Internal Medicine, The University of Iowa, Iowa City, IA 52242 (United States); Tawhai, Merryn H., E-mail: m.tawhai@auckland.ac.nz [Auckland Bioengineering Institute, The University of Auckland, Auckland (New Zealand); Lin, Ching-Long, E-mail: ching-long-lin@uiowa.edu [Department of Mechanical and Industrial Engineering, The University of Iowa, Iowa City, IA 52242 (United States) [Department of Mechanical and Industrial Engineering, The University of Iowa, Iowa City, IA 52242 (United States); IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA 52242 (United States)

    2013-07-01

    A novel algorithm is presented that links local structural variables (regional ventilation and deforming central airways) to global function (total lung volume) in the lung over three imaged lung volumes, to derive a breathing lung model for computational fluid dynamics simulation. The algorithm constitutes the core of an integrative, image-based computational framework for subject-specific simulation of the breathing lung. For the first time, the algorithm is applied to three multi-detector row computed tomography (MDCT) volumetric lung images of the same individual. A key technique in linking global and local variables over multiple images is an in-house mass-preserving image registration method. Throughout breathing cycles, cubic interpolation is employed to ensure C{sub 1} continuity in constructing time-varying regional ventilation at the whole lung level, flow rate fractions exiting the terminal airways, and airway deformation. The imaged exit airway flow rate fractions are derived from regional ventilation with the aid of a three-dimensional (3D) and one-dimensional (1D) coupled airway tree that connects the airways to the alveolar tissue. An in-house parallel large-eddy simulation (LES) technique is adopted to capture turbulent-transitional-laminar flows in both normal and deep breathing conditions. The results obtained by the proposed algorithm when using three lung volume images are compared with those using only one or two volume images. The three-volume-based lung model produces physiologically-consistent time-varying pressure and ventilation distribution. The one-volume-based lung model under-predicts pressure drop and yields un-physiological lobar ventilation. The two-volume-based model can account for airway deformation and non-uniform regional ventilation to some extent, but does not capture the non-linear features of the lung.

  2. Quantum simulations of physics problems

    SciTech Connect (OSTI)

    Somma, R. D.; Ortiz, G.; Knill, E. H.; Gubernatis, J. E.

    2003-01-01

    If a large Quantum Computer (QC) existed today, what type of physical problems could we efficiently simulate on it that we could not efficiently simulate on a classical Turing machine? In this paper we argue that a QC could solve some relevant physical 'questions' more efficiently. The existence of one-to-one mappings between different algebras of observables or between different Hilbert spaces allow us to represent and imitate any physical system by any other one (e.g., a bosonic system by a spin-1/2 system). We explain how these mappings can be performed, and we show quantum networks useful for the efficient evaluation of some physical properties, such as correlation functions and energy spectra.

  3. Stochastic Parallel PARticle Kinetic Simulator

    Energy Science and Technology Software Center (OSTI)

    2008-07-01

    SPPARKS is a kinetic Monte Carlo simulator which implements kinetic and Metropolis Monte Carlo solvers in a general way so that they can be hooked to applications of various kinds. Specific applications are implemented in SPPARKS as physical models which generate events (e.g. a diffusive hop or chemical reaction) and execute them one-by-one. Applications can run in paralle so long as the simulation domain can be partitoned spatially so that multiple events can be invokedmoreĀ Ā» simultaneously. SPPARKS is used to model various kinds of mesoscale materials science scenarios such as grain growth, surface deposition and growth, and reaction kinetics. It can also be used to develop new Monte Carlo models that hook to the existing solver and paralle infrastructure provided by the code.Ā«Ā less

  4. Building America House Simulation Protocols

    SciTech Connect (OSTI)

    Hendron, Robert; Engebrecht, Cheryn

    2010-09-01

    The House Simulation Protocol document was developed to track and manage progress toward Building America's multi-year, average whole-building energy reduction research goals for new construction and existing homes, using a consistent analytical reference point. This report summarizes the guidelines for developing and reporting these analytical results in a consistent and meaningful manner for all home energy uses using standard operating conditions.

  5. Consortium for Advanced Battery Simulation

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

    Battery Simulation - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management Programs Advanced

  6. Bus Rollover Testing and Simulation

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

    Bus Rollover Testing And Simulation Computational Structural Mechanics Collaborator Research Highlights - Florida State University & Florida Department of Transportation Current research conducted at FAMU-FSU College of Engineering pertains to comprehensive crashworthiness and safety assessment of a paratransit bus on a Chevrolet 138" wheelbase. The design process of passenger compartment structure in paratransit buses is not regulated by any of crashworthiness standards. FAMU-FSU

  7. Modeling and Simulation for Safeguards

    SciTech Connect (OSTI)

    Swinhoe, Martyn T.

    2012-07-26

    The purpose of this talk is to give an overview of the role of modeling and simulation in Safeguards R&D and introduce you to (some of) the tools used. Some definitions are: (1) Modeling - the representation, often mathematical, of a process, concept, or operation of a system, often implemented by a computer program; (2) Simulation - the representation of the behavior or characteristics of one system through the use of another system, especially a computer program designed for the purpose; and (3) Safeguards - the timely detection of diversion of significant quantities of nuclear material. The role of modeling and simulation are: (1) Calculate amounts of material (plant modeling); (2) Calculate signatures of nuclear material etc. (source terms); and (3) Detector performance (radiation transport and detection). Plant modeling software (e.g. FACSIM) gives the flows and amount of material stored at all parts of the process. In safeguards this allow us to calculate the expected uncertainty of the mass and evaluate the expected MUF. We can determine the measurement accuracy required to achieve a certain performance.

  8. The Adaptive Multi-scale Simulation Infrastructure

    SciTech Connect (OSTI)

    Tobin, William R.

    2015-09-01

    The Adaptive Multi-scale Simulation Infrastructure (AMSI) is a set of libraries and tools developed to support the development, implementation, and execution of general multimodel simulations. Using a minimal set of simulation meta-data AMSI allows for minimally intrusive work to adapt existent single-scale simulations for use in multi-scale simulations. Support for dynamic runtime operations such as single- and multi-scale adaptive properties is a key focus of AMSI. Particular focus has been spent on the development on scale-sensitive load balancing operations to allow single-scale simulations incorporated into a multi-scale simulation using AMSI to use standard load-balancing operations without affecting the integrity of the overall multi-scale simulation.

  9. Library Analog Semiconductor Devices SPICE Simulators

    Energy Science and Technology Software Center (OSTI)

    1996-07-23

    SPICE-SANDIA.LIB is a library of parameter sets and macromodels of semiconductor devices. They are used with Spice-based (SPICE is a program for electronic circuit analysis) simulators to simulate electronic circuits.

  10. Compact simulators can improve fossil plant operation

    SciTech Connect (OSTI)

    Fray, R.; Divakaruni, S.M. )

    1995-01-01

    This article examines new and affordable technology that can simulate operations in real time and is finding application across a broad spectrum of power plant designs. A significant breakthrough for utilities, compact simulator technology, has reduced the cost of replica simulators by a factor of five to 10. This affordable technology, combined with innovative software developments, can realistically simulate the operation of fossil power plants in real time on low-cost PC or workstation platforms.

  11. EC-130H Simulator Training Operations Facility

    High Performance Buildings Database

    Tucson, AZ The EC-130H Simulator Training Operations Facility at Davis-Monthan Air Force Base serves the mission of the 42nd Electronic Combat Squadron by providing state-of-the-art training facilities for students, instructors and support staff. Three simulator bays house one flight deck simulator and two mission crew simulators. Administrative and support areas are provided for day-to-day operations. These areas include offices, conference rooms, break rooms, and briefing rooms.

  12. Tool - Transportation System Simulation (POLARIS) | Argonne National

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

    Laboratory Tool - Transportation System Simulation (POLARIS) Tool - Transportation System Simulation (POLARIS) POLARIS is a high-performance, open-source agent-based modeling framework designed for simulating large-scale transportation systems. The suite includes a discrete-event engine, memory management, visualization capabilities, and an extensible repository of common transportation objects which allows the rapid development of simulation software that satisfy individual project needs. A

  13. Sandia National Laboratories: Advanced Simulation and Computing...

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

    ASC Advanced Simulation and Computing Computational Systems & Software Environment Crack Modeling The Computational Systems & Software Environment program builds integrated,...

  14. Experiments āœš Simulations = Better Nuclear Power Research

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

    Experiments + Simulations = Better Nuclear Power Research Experiments āœš Simulations = Better Nuclear Power Research Atomic Level Simulations Enhance Characterization of Radiation Damage July 31, 2015 Contact: Kathy Kincade, +1 510 495 2124, kkincade@lbl.gov Radiation Damage PNNL In a study featured on the cover of a Journal of Materials Research focus issue, an international research collaboration used molecular dynamics simulations run at NERSC to identify atomic-level details of early-stage

  15. Decades of Wind Turbine Load Simulation

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

    Decades of Wind Turbine Load Simulation Matthew Barone āˆ— , Joshua Paquette ā€  , Brian Resor ā€” Sandia National Laboratories Ā§ , Albuquerque, NM 87185 Lance Manuel Ā¶ University of Texas, Austin, TX 78712 A high-performance computer was used to simulate ninety-six years of operation of a five megawatt wind turbine. Over five million aero-elastic simulations were performed, with each simulation consisting of wind turbine operation for a ten minute period in turbulent wind conditions. These

  16. Advanced Modeling & Simulation | Department of Energy

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

    Advanced Modeling & Simulation Advanced Modeling & Simulation Advanced Modeling & Simulation ADVANCING THE STATE OF THE ART Innovation advances science. Historically, innovation resulted almost exclusively from fundamental theories combined with observation and experimentation over time. With advancements in engineering, computing power and visualization tools, scientists from all disciplines are gaining insights into physical systems in ways not possible with traditional approaches

  17. Simulated nuclear reactor fuel assembly

    DOE Patents [OSTI]

    Berta, Victor T. (Idaho Falls, ID)

    1993-01-01

    An apparatus for electrically simulating a nuclear reactor fuel assembly. It includes a heater assembly having a top end and a bottom end and a plurality of concentric heater tubes having electrical circuitry connected to a power source, and radially spaced from each other. An outer target tube and an inner target tube is concentric with the heater tubes and with each other, and the outer target tube surrounds and is radially spaced from the heater tubes. The inner target tube is surrounded by and radially spaced from the heater tubes and outer target tube. The top of the assembly is generally open to allow for the electrical power connection to the heater tubes, and the bottom of the assembly includes means for completing the electrical circuitry in the heater tubes to provide electrical resistance heating to simulate the power profile in a nuclear reactor. The embedded conductor elements in each heater tube is split into two halves for a substantial portion of its length and provided with electrical isolation such that each half of the conductor is joined at one end and is not joined at the other end.

  18. Simulated nuclear reactor fuel assembly

    DOE Patents [OSTI]

    Berta, V.T.

    1993-04-06

    An apparatus for electrically simulating a nuclear reactor fuel assembly. It includes a heater assembly having a top end and a bottom end and a plurality of concentric heater tubes having electrical circuitry connected to a power source, and radially spaced from each other. An outer target tube and an inner target tube is concentric with the heater tubes and with each other, and the outer target tube surrounds and is radially spaced from the heater tubes. The inner target tube is surrounded by and radially spaced from the heater tubes and outer target tube. The top of the assembly is generally open to allow for the electrical power connection to the heater tubes, and the bottom of the assembly includes means for completing the electrical circuitry in the heater tubes to provide electrical resistance heating to simulate the power profile in a nuclear reactor. The embedded conductor elements in each heater tube is split into two halves for a substantial portion of its length and provided with electrical isolation such that each half of the conductor is joined at one end and is not joined at the other end.

  19. General Reactive Atomistic Simulation Program

    Energy Science and Technology Software Center (OSTI)

    2004-09-22

    GRASP (General Reactive Atomistic Simulation Program) is primarily intended as a molecular dynamics package for complex force fields, The code is designed to provide good performance for large systems, either in parallel or serial execution mode, The primary purpose of the code is to realistically represent the structural and dynamic properties of large number of atoms on timescales ranging from picoseconds up to a microsecond. Typically the atoms form a representative sample of some material,moreĀ Ā» such as an interface between polycrystalline silicon and amorphous silica. GRASP differs from other parallel molecular dynamics codes primarily due to itĀ’s ability to handle relatively complicated interaction potentials and itĀ’s ability to use more than one interaction potential in a single simulation. Most of the computational effort goes into the calculation of interatomic forces, which depend in a complicated way on the positions of all the atoms. The forces are used to integrate the equations of motion forward in time using the so-called velocity Verlet integration scheme. Alternatively, the forces can be used to find a minimum energy configuration, in which case a modified steepest descent algorithm is used.Ā«Ā less

  20. Multiphysics simulations: challenges and opportunities.

    SciTech Connect (OSTI)

    Keyes, D.; McInnes, L. C.; Woodward, C.; Gropp, W.; Myra, E.; Pernice, M.

    2012-11-29

    This report is an outcome of the workshop Multiphysics Simulations: Challenges and Opportunities, sponsored by the Institute of Computing in Science (ICiS). Additional information about the workshop, including relevant reading and presentations on multiphysics issues in applications, algorithms, and software, is available via https://sites.google.com/site/icismultiphysics2011/. We consider multiphysics applications from algorithmic and architectural perspectives, where 'algorithmic' includes both mathematical analysis and computational complexity and 'architectural' includes both software and hardware environments. Many diverse multiphysics applications can be reduced, en route to their computational simulation, to a common algebraic coupling paradigm. Mathematical analysis of multiphysics coupling in this form is not always practical for realistic applications, but model problems representative of applications discussed herein can provide insight. A variety of software frameworks for multiphysics applications have been constructed and refined within disciplinary communities and executed on leading-edge computer systems. We examine several of these, expose some commonalities among them, and attempt to extrapolate best practices to future systems. From our study, we summarize challenges and forecast opportunities. We also initiate a modest suite of test problems encompassing features present in many applications.

  1. Multiphysics Object Oriented Simulation Environment

    Energy Science and Technology Software Center (OSTI)

    2014-02-12

    The Multiphysics Object Oriented Simulation Environment (MOOSE) software library developed at Idaho National Laboratory is a tool. MOOSE, like other tools, doesnĀ’t actually complete a task. Instead, MOOSE seeks to reduce the effort required to create engineering simulation applications. MOOSE itself is a software library: a blank canvas upon which you write equations and then MOOSE can help you solve them. MOOSE is comparable to a spreadsheet application. A spreadsheet, by itself, doesnĀ’t do anything.moreĀ Ā» Only once equations are entered into it will a spreadsheet application compute anything. Such is the same for MOOSE. An engineer or scientist can utilize the equation solvers within MOOSE to solve equations related to their area of study. For instance, a geomechanical scientist can input equations related to water flow in underground reservoirs and MOOSE can solve those equations to give the scientist an idea of how water could move over time. An engineer might input equations related to the forces in steel beams in order to understand the load bearing capacity of a bridge. Because MOOSE is a blank canvas it can be useful in many scientific and engineering pursuits.Ā«Ā less

  2. TSA RPM Simulator 1.0

    Energy Science and Technology Software Center (OSTI)

    2009-12-02

    The software listed here is a simulator for TSA Radiation Portal Monitors with version 1.10.1A firmware. The simulator provides messages similar to those provided by this piece of equipment.To facilitate testing of the Second Line of Defense systems and similar software products from commercial software vendors, this software simulation application has been developed that simulate the TSA Radiation Portal Monitor that Second Line of Defense communications software systems must interface with. The primary use ofmoreĀ Ā» this simulator is for testing of both Sandia developed and DOE contractor developed software.Ā«Ā less

  3. TSA RPM Simulator 1.0

    SciTech Connect (OSTI)

    2009-12-02

    The software listed here is a simulator for TSA Radiation Portal Monitors with version 1.10.1A firmware. The simulator provides messages similar to those provided by this piece of equipment.To facilitate testing of the Second Line of Defense systems and similar software products from commercial software vendors, this software simulation application has been developed that simulate the TSA Radiation Portal Monitor that Second Line of Defense communications software systems must interface with. The primary use of this simulator is for testing of both Sandia developed and DOE contractor developed software.

  4. Microgrid and Inverter Control and Simulator Software

    Energy Science and Technology Software Center (OSTI)

    2012-09-13

    A collection of software that can simulate the operation of an inverter on a microgrid or control a real inverter. In addition, it can simulate the control of multiple nodes on a microgrid." Application: Simulation of inverters and microgrids; control of inverters on microgrids." The MMI submodule is designed to control custom inverter hardware, and to simulate that hardware. The INVERTER submodule is only the simulator code, and is of an earlier generation than themoreĀ Ā»simulator in MMI. The MICROGRID submodule is an agent-based simulator of multiple nodes on a microgrid which presents a web interface. The WIND submodule produces movies of wind data with a web interface.Ā«Ā less

  5. Framework for Network Co-Simulation

    Energy Science and Technology Software Center (OSTI)

    2014-01-09

    The Framework for Network Co-Simulation (FNCS) uses a federated approach to integrate simulations which may have differing time scales. Special consideration is given to integration with a communication network simulation such that inter-simulation messages may be optionally routed through and delayed by such a simulation. In addition, FNCS uses novel time synchronization algorithms to accelerate co-simulation including the application of speculative multithreading. FNCS accomplishes all of these improvements with minimal end user intervention. Simulations canmoreĀ Ā» be integrated using FNCS while maintaining their original model input files simply by linking with the FNCS library and making appropriate calls into the FNCS API.Ā«Ā less

  6. Sandia Energy - Numerical Simulations of Hydrokinetics in the...

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

    Numerical Simulations of Hydrokinetics in the Roza Canal, Yakima Washington Home Renewable Energy Energy Water Power Computational Modeling & Simulation Numerical Simulations of...

  7. System Simulations of Hybrid Electric Vehicles with Focus on...

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

    System Simulations of Hybrid Electric Vehicles with Focus on Emissions System Simulations of Hybrid Electric Vehicles with Focus on Emissions Comparative simulations of hybrid ...

  8. Waste simulant development for evaluation of LLW melter system technology

    SciTech Connect (OSTI)

    Shade, J.W.

    1994-05-25

    This document describes the LLW simulant compositions, basis for the simulants, and recipes for preparing nonradioactive simulants for LLW melter tests.

  9. Simulation enabled safeguards assessment methodology

    SciTech Connect (OSTI)

    Bean, Robert; Bjornard, Trond; Larson, Tom

    2007-07-01

    It is expected that nuclear energy will be a significant component of future supplies. New facilities, operating under a strengthened international nonproliferation regime will be needed. There is good reason to believe virtual engineering applied to the facility design, as well as to the safeguards system design will reduce total project cost and improve efficiency in the design cycle. Simulation Enabled Safeguards Assessment MEthodology has been developed as a software package to provide this capability for nuclear reprocessing facilities. The software architecture is specifically designed for distributed computing, collaborative design efforts, and modular construction to allow step improvements in functionality. Drag and drop wire-frame construction allows the user to select the desired components from a component warehouse, render the system for 3D visualization, and, linked to a set of physics libraries and/or computational codes, conduct process evaluations of the system they have designed. (authors)

  10. Assessment of Molecular Modeling & Simulation

    SciTech Connect (OSTI)

    2002-01-03

    This report reviews the development and applications of molecular and materials modeling in Europe and Japan in comparison to those in the United States. Topics covered include computational quantum chemistry, molecular simulations by molecular dynamics and Monte Carlo methods, mesoscale modeling of material domains, molecular-structure/macroscale property correlations like QSARs and QSPRs, and related information technologies like informatics and special-purpose molecular-modeling computers. The panel's findings include the following: The United States leads this field in many scientific areas. However, Canada has particular strengths in DFT methods and homogeneous catalysis; Europe in heterogeneous catalysis, mesoscale, and materials modeling; and Japan in materials modeling and special-purpose computing. Major government-industry initiatives are underway in Europe and Japan, notably in multi-scale materials modeling and in development of chemistry-capable ab-initio molecular dynamics codes.

  11. Earthquake Simulator Finds Tremor Triggers

    SciTech Connect (OSTI)

    Johnson, Paul

    2015-03-27

    Using a novel device that simulates earthquakes in a laboratory setting, a Los Alamos researcher has found that seismic waves-the sounds radiated from earthquakes-can induce earthquake aftershocks, often long after a quake has subsided. The research provides insight into how earthquakes may be triggered and how they recur. Los Alamos researcher Paul Johnson and colleague Chris Marone at Penn State have discovered how wave energy can be stored in certain types of granular materials-like the type found along certain fault lines across the globe-and how this stored energy can suddenly be released as an earthquake when hit by relatively small seismic waves far beyond the traditional “aftershock zone” of a main quake. Perhaps most surprising, researchers have found that the release of energy can occur minutes, hours, or even days after the sound waves pass; the cause of the delay remains a tantalizing mystery.

  12. Electricity Generation Cost Simulation Model

    Energy Science and Technology Software Center (OSTI)

    2003-04-25

    The Electricity Generation Cost Simulation Model (GENSIM) is a user-friendly, high-level dynamic simulation model that calculates electricity production costs for variety of electricity generation technologies, including: pulverized coal, gas combustion turbine, gas combined cycle, nuclear, solar (PV and thermal), and wind. The model allows the user to quickly conduct sensitivity analysis on key variables, including: capital, O&M, and fuel costs; interest rates; construction time; heat rates; and capacity factors. The model also includes consideration ofmoreĀ Ā» a wide range of externality costs and pollution control options for carbon dioxide, nitrogen oxides, sulfur dioxide, and mercury. Two different data sets are included in the model; one from the U.S. Department of Energy (DOE) and the other from Platt's Research Group. Likely users of this model include executives and staff in the Congress, the Administration and private industry (power plant builders, industrial electricity users and electric utilities). The model seeks to improve understanding of the economic viability of various generating technologies and their emission trade-offs. The base case results using the DOE data, indicate that in the absence of externality costs, or renewable tax credits, pulverized coal and gas combined cycle plants are the least cost alternatives at 3.7 and 3.5 cents/kwhr, respectively. A complete sensitivity analysis on fuel, capital, and construction time shows that these results coal and gas are much more sensitive to assumption about fuel prices than they are to capital costs or construction times. The results also show that making nuclear competitive with coal or gas requires significant reductions in capital costs, to the $1000/kW level, if no other changes are made. For renewables, the results indicate that wind is now competitive with the nuclear option and is only competitive with coal and gas for grid connected applications if one includes the federal production tax credit of 1.8 cents/kwhr.Ā«Ā less

  13. New era for fossil power plant simulators

    SciTech Connect (OSTI)

    Hoffman, S.

    1995-09-01

    At a time when the utility industry is focusing on products and services that can enhance competitiveness, affordable fossil plant simulators are a welcome technology. In just a few years, these simulators have progressed from being an expensive tool that few utilities could afford to being a technology that many utilities feel they can`t do without. Offering a variety of benefits in the areas of fossil plant training and engineering, today`s simulators are flexible, effective, and much less expensive than their counterparts in the 1980s. A vigorous EPRI development and demonstration effort has advanced simulators beyond operator issues to a new era of application, ranging from the training of engineers to the design and testing of power plant technologies. And the technologies that have resulted from simulator development and enhancement will have beneficial uses beyond plant simulation. 8 figs.

  14. Emulation to simulate low resolution atmospheric data

    SciTech Connect (OSTI)

    Hebbur Venkata Subba Rao, Vishwas [ORNL; Archibald, Richard K [ORNL; Evans, Katherine J [ORNL

    2012-08-01

    Climate simulations require significant compute power, they are complex and therefore it is time consuming to simulate them. We have developed an emulator to simulate unknown climate datasets. The emulator uses stochastic collocation and multi-dimensional in- terpolation to simulate the datasets. We have used the emulator to determine various physical quantities such as temperature, short and long wave cloud forcing, zonal winds etc. The emulation gives results which are very close to those obtained by simulations. The emulator was tested on 2 degree atmospheric datasets. The work evaluates the pros and cons of evaluating the mean first and inter- polating and vice versa. To determine the physical quantities, we have assumed them to be a function of time, longitude, latitude and a random parameter. We have looked at parameters that govern high stable clouds, low stable clouds, timescale for convection etc. The emulator is especially useful as it requires negligible compute times when compared to the simulation itself.

  15. Operational forecasting based on a modified Weather Research and Forecasting model

    SciTech Connect (OSTI)

    Lundquist, J; Glascoe, L; Obrecht, J

    2010-03-18

    Accurate short-term forecasts of wind resources are required for efficient wind farm operation and ultimately for the integration of large amounts of wind-generated power into electrical grids. Siemens Energy Inc. and Lawrence Livermore National Laboratory, with the University of Colorado at Boulder, are collaborating on the design of an operational forecasting system for large wind farms. The basis of the system is the numerical weather prediction tool, the Weather Research and Forecasting (WRF) model; large-eddy simulations and data assimilation approaches are used to refine and tailor the forecasting system. Representation of the atmospheric boundary layer is modified, based on high-resolution large-eddy simulations of the atmospheric boundary. These large-eddy simulations incorporate wake effects from upwind turbines on downwind turbines as well as represent complex atmospheric variability due to complex terrain and surface features as well as atmospheric stability. Real-time hub-height wind speed and other meteorological data streams from existing wind farms are incorporated into the modeling system to enable uncertainty quantification through probabilistic forecasts. A companion investigation has identified optimal boundary-layer physics options for low-level forecasts in complex terrain, toward employing decadal WRF simulations to anticipate large-scale changes in wind resource availability due to global climate change.

  16. Combined statistical and dynamical assessment of simulated

    Office of Scientific and Technical Information (OSTI)

    vegetation-rainfall in North Africa during the mid-Holocene* (Journal Article) | SciTech Connect Combined statistical and dynamical assessment of simulated vegetation-rainfall in North Africa during the mid-Holocene* Citation Details In-Document Search Title: Combined statistical and dynamical assessment of simulated vegetation-rainfall in North Africa during the mid-Holocene* A negative feedback of vegetation cover on subsequent annual precipitation is simulated for the mid-Holocene over

  17. Molecular Dynamics Simulation Studies of Electrolytes and

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

    Electrolyte/Electrode Interfaces | Department of Energy Dynamics Simulation Studies of Electrolytes and Electrolyte/Electrode Interfaces Molecular Dynamics Simulation Studies of Electrolytes and Electrolyte/Electrode Interfaces 2010 DOE Vehicle Technologies and Hydrogen Programs Annual Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C. PDF icon es058_smith_2010_p.pdf More Documents & Publications Molecular dynamics simulation and ab intio studies of electrolytes

  18. Clot Busting Simulations Test Potential Stroke Treatment

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

    Clot Busting Simulations Test Potential Stroke Treatment Clot Busting Simulations Test Potential Stroke Treatment September 24, 2013 Contact: Linda Vu, +1 510 495 2402, lvu@lbl.gov Calvariasetup.jpg The array transducer in position above the calvaria (skull). Shown are the ends of the array elements above the computational model of the skull. Researchers are using computer simulations to investigate how ultrasound and tiny bubbles injected into the bloodstream might break up blood clots,

  19. Explosive simulants for testing explosive detection systems

    DOE Patents [OSTI]

    Kury, John W. (Danville, CA); Anderson, Brian L. (Lodi, CA)

    1999-09-28

    Explosives simulants that include non-explosive components are disclosed that facilitate testing of equipment designed to remotely detect explosives. The simulants are non-explosive, non-hazardous materials that can be safely handled without any significant precautions. The simulants imitate real explosives in terms of mass density, effective atomic number, x-ray transmission properties, and physical form, including moldable plastics and emulsions/gels.

  20. Distributed Energy Technology Simulator: Microturbine Demonstration,

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

    October 2001 | Department of Energy Simulator: Microturbine Demonstration, October 2001 Distributed Energy Technology Simulator: Microturbine Demonstration, October 2001 This 2001 paper discusses the National Rural Energy Cooperative Association's (NRECA's) and Sandia National Laboratories' support of an effort to develop a device that will simulate the technical and economic performance of distributed energy technologies. NRECA's Cooperative Research Network (CRN) is taking the lead in this

  1. Advanced Simulation Capability for Environmental Management (ASCEM) |

    Energy Savers [EERE]

    Department of Energy Advanced Simulation Capability for Environmental Management (ASCEM) Advanced Simulation Capability for Environmental Management (ASCEM) Advanced Simulation Capability for Environmental Management (ASCEM) ASCEM is being developed to provide a tool and approach to facilitate robust and standardized development of performance and risk assessments for cleanup and closure activities throughout the EM complex. The ASCEM team is composed of scientists from eight National

  2. House Simulation Protocols Report | Department of Energy

    Energy Savers [EERE]

    Residential Buildings Ā» Building America Ā» House Simulation Protocols Report House Simulation Protocols Report Report cover Building America's House Simulation Protocols report is designed to assist researchers in tracking the progress of multiyear, whole-building energy reduction against research goals for new and existing homes. These protocols are preloaded into BEopt and use a consistent approach for defining a reference building, so that all projects can be compared to each other. The

  3. House Simulation Protocols (Building America Benchmark) - Building...

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

    profile for House Simulation Protocols. See an example of this Top Innovation in action. Find more case studies of Building America projects across the country that ...

  4. Multiscale Simulations of Human Pathologies | Argonne Leadership...

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

    apex. Inset shows the time evolution of thrombus formation. George Karniadakis, Brown University Multiscale Simulations of Human Pathologies PI Name: George Karniadakis PI...

  5. MOOSE simulating nuclear reactor CRUD buildup

    ScienceCinema (OSTI)

    None

    2014-07-21

    This simulation uses multiple physical models to show how the buildup of boron deposits on reactor fuel can affect performance and the reactor's power profile.

  6. MOOSE simulating nuclear reactor CRUD buildup

    SciTech Connect (OSTI)

    2014-02-06

    This simulation uses multiple physical models to show how the buildup of boron deposits on reactor fuel can affect performance and the reactor's power profile.

  7. Parallel Implementation of Power System Dynamic Simulation

    SciTech Connect (OSTI)

    Jin, Shuangshuang; Huang, Zhenyu; Diao, Ruisheng; Wu, Di; Chen, Yousu

    2013-07-21

    Dynamic simulation of power system transient stability is important for planning, monitoring, operation, and control of electrical power systems. However, modeling the system dynamics and network involves the computationally intensive time-domain solution of numerous differential and algebraic equations (DAE). This results in a transient stability implementation that may not maintain the real-time constraints of an online security assessment. This paper presents a parallel implementation of the dynamic simulation on a high-performance computing (HPC) platform using parallel simulation algorithms and computation architectures. It enables the simulation to run even faster than real time, enabling the “look-ahead” capability of upcoming stability problems in the power grid.

  8. Erratum: Connection between Newtonian simulations and general...

    Office of Scientific and Technical Information (OSTI)

    RELATIVITY THEORY; MANY-BODY PROBLEM; SIMULATION FIELD THEORIES; INVARIANCE PRINCIPLES; MECHANICS; RELATIVITY THEORY Word Cloud More Like This Full Text Journal Articles DOI:...

  9. Advanced simulation capability for environmental management ...

    Office of Scientific and Technical Information (OSTI)

    environmental management (ASCEM): An overview of initial results Citation Details In-Document Search Title: Advanced simulation capability for environmental management (ASCEM): An ...

  10. Radio Channel Simulator - Energy Innovation Portal

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

    (RCSim) is a simulation package for making site-specific predictions of radio signal strength. The software computes received power at discrete grid points as a function...

  11. Interoperable Technologies for Advanced Petascale Simulations...

    Office of Scientific and Technical Information (OSTI)

    power plant fuel rods. We have implemented the fluid-structure interaction for 3D windmill and parachute simulations. We have continued our collaboration with PNNL, BNL, LANL,...

  12. Dynamics of Molecular Clouds: Observations, Simulations, and...

    Office of Scientific and Technical Information (OSTI)

    Conference: Dynamics of Molecular Clouds: Observations, Simulations, and NIF Experiments Citation Details In-Document Search Title: Dynamics of Molecular Clouds: Observations,...

  13. Modeling-Computer Simulations | Open Energy Information

    Open Energy Info (EERE)

    the risk of inaccurate predictions.1 Potential Pitfalls Uncertainties in initial reservoir conditions and other model inputs can cause inaccuracies in simulations, which...

  14. Communication: Quantum molecular dynamics simulation of liquid...

    Office of Scientific and Technical Information (OSTI)

    Communication: Quantum molecular dynamics simulation of liquid para-hydrogen by nuclear and electron wave packet approach Citation Details In-Document Search Title: Communication:...

  15. Advancing Internal Combustion Engine Simulations using Sensitivity...

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

    Advancing Internal Combustion Engine Simulations using Sensitivity Analysis PI Name: Sibendu Som PI Email: ssom@anl.gov Institution: Argonne National Laboratory Allocation Program:...

  16. Sandia National Laboratories: Advanced Simulation and Computing...

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

    Crack Modeling The Physics & Engineering Models program provides the models and databases used in simulations supporting the U.S. stockpile. These models and databases...

  17. Sandia National Laboratories: Advanced Simulation Computing:...

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

    These collaborations help solve the challenges of developing computing platforms and simulation tools across a number of disciplines. Computer Science Research Institute The...

  18. Coiled Fiber Pulsed Laser Simulator

    Energy Science and Technology Software Center (OSTI)

    2009-01-29

    This suite of codes simulates the transient output pulse from an optically-pumped coiled fiber amplifier. The input pulse is assumed to have a Gaussian time dependence and a spatial dependence that may be Gaussian or an eigenmode of the straight of bent fiber computed using bend10 or bend20. Only one field component is used (semivectorial approximation). The fully-spatially-dependent fiber gain profile is specified is subroutines "inversion" and "interp_inversion" and is presently read from a datamoreĀ Ā» file, although other means of specifying fiber gain could be reallized through modification of these subroutines. The input pulse is propagated through the fiber, including the following physical effects: spatial and temporal gain saturation, self-focusing, bend losses, and confinement from a user-defined fiber index profile. The user can follow the propagation progress with 3D graphics that show an intensity profile via user-modifiable cutting planes through the time space axes. A restart capability is also included. Approximate solutions in the frequency domain may be obtained much faster using the auxilliary codes bendbpm10 (full vector), bendbpm20 (semivectoral), and bendbpm21 (semivectoral with gain sheet spproximation for gain and self-focusing). These codes all include bend loss and spatial (but not temporal) gain saturation.Ā«Ā less

  19. Simulation and sequential dynamical systems

    SciTech Connect (OSTI)

    Mortveit, H.S.; Reidys, C.M.

    1999-06-01

    Computer simulations have a generic structure. Motivated by this the authors present a new class of discrete dynamical systems that captures this structure in a mathematically precise way. This class of systems consists of (1) a loopfree graph {Upsilon} with vertex set {l_brace}1,2,{hor_ellipsis},n{r_brace} where each vertex has a binary state, (2) a vertex labeled set of functions (F{sub i,{Upsilon}}:F{sub 2}{sup n} {yields} F{sub 2}{sup n}){sub i} and (3) a permutation {pi} {element_of} S{sub n}. The function F{sub i,{Upsilon}} updates the state of vertex i as a function of the states of vertex i and its {Upsilon}-neighbors and leaves the states of all other vertices fixed. The permutation {pi} represents the update ordering, i.e., the order in which the functions F{sub i,{Upsilon}} are applied. By composing the functions F{sub i,{Upsilon}} in the order given by {pi} one obtains the dynamical system (equation given in paper), which the authors refer to as a sequential dynamical system, or SDS for short. The authors will present bounds for the number of functionally different systems and for the number of nonisomorphic digraphs {Gamma}[F{sub {Upsilon}},{pi}] that can be obtained by varying the update order and applications of these to specific graphs and graph classes.

  20. Simulating Collisions for Hydrokinetic Turbines

    SciTech Connect (OSTI)

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

    2013-10-01

    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.

  1. Transient simulation of absorption machines

    SciTech Connect (OSTI)

    Anand, D.K.; Allen, R.W.; Kumar, B.

    1982-08-01

    This paper presents a model for a water-cooled Lithium-Bromide/water absorption chiller and predicts its transient response both during the start-up phase and during the shutoff period. The simulation model incorporates such influencing factors as the thermodynamic properties of the working fluid, the absorbent, the heat-transfer configuration of different components of the chiller and related physical data. The time constants of different components are controlled by a set of key parameters that have been identified in this study. The results show a variable but at times significant amount of time delay before the chiller capacity gets close to its steady-state value. The model is intended to provide an insight into the mechanism of build-up to steady-state performance. By recognizing the significant factors contributing to transient degradation, steps can be taken to reduce such degradation. The evaluation of the residual capacity in the shut-off period will yield more realistic estimates of chiller COP for a chiller satisfying dynamic space cooling load.

  2. Transient simulation of absorption machines

    SciTech Connect (OSTI)

    Anand, D.K.; Allen, R.W.; Kumar, B.

    1982-08-01

    This paper presents a model for a water-cooled Lithium-Bromide/water absorption chiller and predicts its transient response both during the start-up phase and during the shutoff period. The simulation model incorporates such influencing factors as the thermodynamic properties of the working fluid, the absorbent, the heat-transfer configuration of different components of the chiller and related physical data. The time constants of different components are controlled by a set of key parameters that have been identified in this study. The results show a variable but at times significant amount of time delay before the chiller capacity gets close to its steadystate value. The model is intended to provide an insight into the mechanism of build-up to steady-state performance. By recognizing the significant factors contributing to transient degradation, steps can be taken to reduce such degradation. The evaluation of the residual capacity in the shut-off period will yield more realistic estimates of chiller COP for a chiller satisfying dynamic space cooling load.

  3. International symposium on fuel rod simulators: development and application

    SciTech Connect (OSTI)

    McCulloch, R.W.

    1981-05-01

    Separate abstracts are included for each of the papers presented concerning fuel rod simulator operation and performance; simulator design and evaluation; clad heated fuel rod simulators and fuel rod simulators for cladding investigations; fuel rod simulator components and inspection; and simulator analytical modeling. Ten papers have previously been input to the Energy Data Base.

  4. Posters Radar/Radiometer Retrievals of Cloud Liquid Water and

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

    1 Posters Radar/Radiometer Retrievals of Cloud Liquid Water and Drizzle: Analysis Using Data from a Three-Dimensional Large Eddy Simulation of Marine Stratocumulus Clouds G. Feingold Cooperative Institute for Research in Environmental Sciences University of Colorado Boulder, Colorado A. S. Frisch National Oceanic and Atmospheric Administration Environmental Technology Laboratory Boulder, Colorado B. Stevens and W. R. Cotton Colorado State University Fort Collins, Colorado Introduction Marine

  5. Research Highlight

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

    Is Cumulus Drag a Rayleigh Drag? Download a printable PDF Submitter: Romps, D., Lawrence Berkeley National Laboratory Area of Research: Cloud Processes Working Group(s): Cloud Life Cycle Journal Reference: Romps DM. 2013. "Rayleigh damping in the free troposphere." Journal of the Atmospheric Sciences, , . ACCEPTED. Hovmoller diagrams of wind profiles in a large-eddy simulation of deep convection. Note the different damping rates and descent speeds for different wavelengths. In toy

  6. ARM - Feature Stories and Releases Article

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

    15, 2015 [Facility News, Feature Stories and Releases] Pilot Phase Begins for Routine Large-Eddy Simulations Bookmark and Share William Gustafson, Pacific Northwest National Laboratory William Gustafson, Pacific Northwest National Laboratory Researchers target observation and modeling together for a new level of scientific analysis on climate When it comes to clouds, the Earth's energy budget, and tiny aerosols, scientists don't have all the answers. However, each atmospheric model improvement

  7. ARM - LASSO Pilot Project Timeline

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

    Pilot Project Timeline LASSO Information LASSO Home LASSO Backgrounder Pilot Phase Begins for Routine Large-Eddy Simulations Pilot Project Timeline Presentations Science LASSO Implementation Strategy Related Information ARM Decadal Vision Archive of LASSO Information e-mail list LASSO Collaboration Letter Contacts William Gustafson, Lead Principal Investigator Andrew Vogelmann, Co-Principal Investigator Hanna Goss, Media Contact LASSO Pilot Project Timeline As the pilot phase progresses toward

  8. Improving Entrainment Rate Parameterization

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

    Entrainment Rate Parameterization For original submission and image(s), see ARM Research Highlights http://www.arm.gov/science/highlights/ Research Highlight Parameterization of entrainment rate is critical for improving representation of cloud- and convection-related processes in climate models; however, much remains unclear. This work seeks to improve understanding and parameterization of entrainment rate by use of aircraft observations and large-eddy simulations of shallow cumulus clouds over

  9. Trace Replay and Network Simulation Tool

    Energy Science and Technology Software Center (OSTI)

    2015-03-23

    TraceR is a trace reply tool built upon the ROSS-based CODES simulation framework. TraceR can be used for predicting network performances and understanding network behavior by simulating messaging in High Performance Computing applications on interconnection networks.

  10. Method for simulating discontinuous physical systems

    DOE Patents [OSTI]

    Baty, Roy S. (Albuquerque, NM); Vaughn, Mark R. (Albuquerque, NM)

    2001-01-01

    The mathematical foundations of conventional numerical simulation of physical systems provide no consistent description of the behavior of such systems when subjected to discontinuous physical influences. As a result, the numerical simulation of such problems requires ad hoc encoding of specific experimental results in order to address the behavior of such discontinuous physical systems. In the present invention, these foundations are replaced by a new combination of generalized function theory and nonstandard analysis. The result is a class of new approaches to the numerical simulation of physical systems which allows the accurate and well-behaved simulation of discontinuous and other difficult physical systems, as well as simpler physical systems. Applications of this new class of numerical simulation techniques to process control, robotics, and apparatus design are outlined.

  11. Simulations of carbon fiber composite delamination tests

    SciTech Connect (OSTI)

    Kay, G

    2007-10-25

    Simulations of mode I interlaminar fracture toughness tests of a carbon-reinforced composite material (BMS 8-212) were conducted with LSDYNA. The fracture toughness tests were performed by U.C. Berkeley. The simulations were performed to investigate the validity and practicality of employing decohesive elements to represent interlaminar bond failures that are prevalent in carbon-fiber composite structure penetration events. The simulations employed a decohesive element formulation that was verified on a simple two element model before being employed to perform the full model simulations. Care was required during the simulations to ensure that the explicit time integration of LSDYNA duplicate the near steady-state testing conditions. In general, this study validated the use of employing decohesive elements to represent the interlaminar bond failures seen in carbon-fiber composite structures, but the practicality of employing the elements to represent the bond failures seen in carbon-fiber composite structures during penetration events was not established.

  12. Cluster computing software for GATE simulations

    SciTech Connect (OSTI)

    Beenhouwer, Jan de; Staelens, Steven; Kruecker, Dirk; Ferrer, Ludovic; D'Asseler, Yves; Lemahieu, Ignace; Rannou, Fernando R.

    2007-06-15

    Geometry and tracking (GEANT4) is a Monte Carlo package designed for high energy physics experiments. It is used as the basis layer for Monte Carlo simulations of nuclear medicine acquisition systems in GEANT4 Application for Tomographic Emission (GATE). GATE allows the user to realistically model experiments using accurate physics models and time synchronization for detector movement through a script language contained in a macro file. The downside of this high accuracy is long computation time. This paper describes a platform independent computing approach for running GATE simulations on a cluster of computers in order to reduce the overall simulation time. Our software automatically creates fully resolved, nonparametrized macros accompanied with an on-the-fly generated cluster specific submit file used to launch the simulations. The scalability of GATE simulations on a cluster is investigated for two imaging modalities, positron emission tomography (PET) and single photon emission computed tomography (SPECT). Due to a higher sensitivity, PET simulations are characterized by relatively high data output rates that create rather large output files. SPECT simulations, on the other hand, have lower data output rates but require a long collimator setup time. Both of these characteristics hamper scalability as a function of the number of CPUs. The scalability of PET simulations is improved here by the development of a fast output merger. The scalability of SPECT simulations is improved by greatly reducing the collimator setup time. Accordingly, these two new developments result in higher scalability for both PET and SPECT simulations and reduce the computation time to more practical values.

  13. Morphology of Gas Release in Physical Simulants

    SciTech Connect (OSTI)

    Daniel, Richard C.; Burns, Carolyn A.; Crawford, Amanda D.; Hylden, Laura R.; Bryan, Samuel A.; MacFarlan, Paul J.; Gauglitz, Phillip A.

    2014-07-03

    This report documents testing activities conducted as part of the Deep Sludge Gas Release Event Project (DSGREP). The testing described in this report focused on evaluating the potential retention and release mechanisms of hydrogen bubbles in underground radioactive waste storage tanks at Hanford. The goal of the testing was to evaluate the rate, extent, and morphology of gas release events in simulant materials. Previous, undocumented scoping tests have evidenced dramatically different gas release behavior from simulants with similar physical properties. Specifically, previous gas release tests have evaluated the extent of release of 30 Pa kaolin and 30 Pa bentonite clay slurries. While both materials are clays and both have equivalent material shear strength using a shear vane, it was found that upon stirring, gas was released immediately and completely from bentonite clay slurry while little if any gas was released from the kaolin slurry. The motivation for the current work is to replicate these tests in a controlled quality test environment and to evaluate the release behavior for another simulant used in DSGREP testing. Three simulant materials were evaluated: 1) a 30 Pa kaolin clay slurry, 2) a 30 Pa bentonite clay slurry, and 3) Rayleigh-Taylor (RT) Simulant (a simulant designed to support DSGREP RT instability testing. Entrained gas was generated in these simulant materials using two methods: 1) application of vacuum over about a 1-minute period to nucleate dissolved gas within the simulant and 2) addition of hydrogen peroxide to generate gas by peroxide decomposition in the simulants over about a 16-hour period. Bubble release was effected by vibrating the test material using an external vibrating table. When testing with hydrogen peroxide, gas release was also accomplished by stirring of the simulant.

  14. SLUDGE BATCH 6/TANK 51 SIMULANT CHEMICAL PROCESS CELL SIMULATIONS

    SciTech Connect (OSTI)

    Koopman, David; Best, David

    2010-04-28

    Qualification simulant testing was completed to determine appropriate processing conditions and assumptions for the Sludge Batch 6 (SB6) Shielded Cells demonstration of the DWPF flowsheet using the qualification sample from Tank 51 for SB6 after SRNL washing. It was found that an acid addition window of 105-139% of the DWPF acid equation (100-133% of the Koopman minimum acid equation) gave acceptable Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) results for nitrite destruction and hydrogen generation. Hydrogen generation occurred continuously after acid addition in three of the four tests. The three runs at 117%, 133%, and 150% stoichiometry (Koopman) were all still producing around 0.1 lb hydrogen/hr at DWPF scale after 42 hours of boiling in the SRAT. The 150% acid run reached 110% of the DWPF SRAT limit of 0.65 lb H{sub 2}/hr, and the 133% acid run reached 75% of the DWPF SME limit of 0.223 lb H{sub 2}/hr. Conversely, nitrous oxide generation was subdued compared to previous sludge batches, staying below 25 lb/hr in all four tests or about a fourth as much as in comparable SB4 testing. Two other processing issues were noted. First, incomplete mercury suspension impacted mercury stripping from the SRAT slurry. This led to higher SRAT product mercury concentrations than targeted (>0.45 wt% in the total solids). Associated with this issue was a general difficulty in quantifying the mass of mercury in the SRAT vessel as a function of time, especially as acid stoichiometry increased. About ten times more mercury was found after drying the 150% acid SME product to powder than was indicated by the SME product sample results. Significantly more mercury was also found in the 133% acid SME product samples than was found during the SRAT cycle sampling. It appears that mercury is segregating from the bulk slurry in the SRAT vessel, as mercury amalgam deposits for example, and is not being resuspended by the agitators. The second processing issue was significant ammonium ion formation as the acid stoichiometry was increased due to the high noble metal-high mercury feed conditions. Ammonium ion was found partitioned between the SRAT product slurry and the condensate from the lab-scale off-gas chiller downstream of the SRAT condenser. The ammonium ion was produced from nitrate ion by formic acid. Formate losses increased with increasing acid stoichiometry reaching 40% at the highest stoichiometry tested. About a third of the formate loss at higher acid stoichiometries appeared to be due to ammonia formation. The full extent of ammonia formation was not determined in these tests, since uncondensed ammonia vapor was not quantified; but total formation was bounded by the combined loss of nitrite and nitrate. Nitrate losses during ammonia formation led to nitrite-to-nitrate conversion values that were negative in three of the four tests. The negative results were an artifact of the calculation that assumes negligible SRAT nitrate losses. The sample data after acid addition indicated that some of the initial nitrite was converted to nitrate, so the amount of nitrate destroyed included nitrite converted to nitrate plus some of the added nitrate from the sludge and nitric acid. It is recommended that DWPF investigate the impact of SME product ammonium salts on melter performance (hydrogen, redox). It was recommended that the SB6 Shielded Cells qualification run be performed at 115% acid stoichiometry and allow about 35 hours of boiling for mercury stripping at the equivalent of a 5,000 lb/hr boil-up rate.

  15. Simulation of water flow in terrestrial systems

    Energy Science and Technology Software Center (OSTI)

    2008-12-18

    ParFlow is a parallel, variabley saturated groundwater flow code that is especially suitable for large scale problem. ParFlow simulates the three-dimensional saturated and variably saturated subsurface flow in heterogeneous porous media in three spatial dimensions. ParFlow's developemt and appkication has been on-ging for more than 10 uear. ParFlow has recently been extended to coupled surface-subsurface flow to enabel the simulation of hillslope runoff and channel routing in a truly integrated fashion. ParFlow simulates the three-dimensionalmoreĀ Ā» varably saturated subsurface flow in strongly heterogeneous porous media in three spatial dimension.Ā«Ā less

  16. FUEL ASSEMBLY SHAKER TEST SIMULATION

    SciTech Connect (OSTI)

    Klymyshyn, Nicholas A.; Sanborn, Scott E.; Adkins, Harold E.; Hanson, Brady D.

    2013-05-30

    This report describes the modeling of a PWR fuel assembly under dynamic shock loading in support of the Sandia National Laboratories (SNL) shaker test campaign. The focus of the test campaign is on evaluating the response of used fuel to shock and vibration loads that a can occur during highway transport. Modeling began in 2012 using an LS-DYNA fuel assembly model that was first created for modeling impact scenarios. SNL’s proposed test scenario was simulated through analysis and the calculated results helped guide the instrumentation and other aspects of the testing. During FY 2013, the fuel assembly model was refined to better represent the test surrogate. Analysis of the proposed loads suggested the frequency band needed to be lowered to attempt to excite the lower natural frequencies of the fuel assembly. Despite SNL’s expansion of lower frequency components in their five shock realizations, pretest predictions suggested a very mild dynamic response to the test loading. After testing was completed, one specific shock case was modeled, using recorded accelerometer data to excite the model. Direct comparison of predicted strain in the cladding was made to the recorded strain gauge data. The magnitude of both sets of strain (calculated and recorded) are very low, compared to the expected yield strength of the Zircaloy-4 material. The model was accurate enough to predict that no yielding of the cladding was expected, but its precision at predicting micro strains is questionable. The SNL test data offers some opportunity for validation of the finite element model, but the specific loading conditions of the testing only excite the fuel assembly to respond in a limited manner. For example, the test accelerations were not strong enough to substantially drive the fuel assembly out of contact with the basket. Under this test scenario, the fuel assembly model does a reasonable job of approximating actual fuel assembly response, a claim that can be verified through direct comparison of model results to recorded test results. This does not offer validation for the fuel assembly model in all conceivable cases, such as high kinetic energy shock cases where the fuel assembly might lift off the basket floor to strike to basket ceiling. This type of nonlinear behavior was not witnessed in testing, so the model does not have test data to be validated against.a basis for validation in cases that substantially alter the fuel assembly response range. This leads to a gap in knowledge that is identified through this modeling study. The SNL shaker testing loaded a surrogate fuel assembly with a certain set of artificially-generated time histories. One thing all the shock cases had in common was an elimination of low frequency components, which reduces the rigid body dynamic response of the system. It is not known if the SNL test cases effectively bound all highway transportation scenarios, or if significantly greater rigid body motion than was tested is credible. This knowledge gap could be filled through modeling the vehicle dynamics of a used fuel conveyance, or by collecting acceleration time history data from an actual conveyance under highway conditions.

  17. Simulating the Next Generation of Energy Technologies

    Broader source: Energy.gov [DOE]

    Computer simulations offer a huge potential for the auto industry to allow us to make modifications to engines faster and cheaper -- and come up with the most energy efficient solution.

  18. Refinery burner simulation design architecture summary.

    SciTech Connect (OSTI)

    Pollock, Guylaine M.; McDonald, Michael James; Halbgewachs, Ronald D.

    2011-10-01

    This report describes the architectural design for a high fidelity simulation of a refinery and refinery burner, including demonstrations of impacts to the refinery if errors occur during the refinery process. The refinery burner model and simulation are a part of the capabilities within the Sandia National Laboratories Virtual Control System Environment (VCSE). Three components comprise the simulation: HMIs developed with commercial SCADA software, a PLC controller, and visualization software. All of these components run on different machines. This design, documented after the simulation development, incorporates aspects not traditionally seen in an architectural design, but that were utilized in this particular demonstration development. Key to the success of this model development and presented in this report are the concepts of the multiple aspects of model design and development that must be considered to capture the necessary model representation fidelity of the physical systems.

  19. Molecular dynamics simulation studies of electrolytes andelectrolyte...

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

    Review and Peer Evaluation Meeting, May 18-22, 2009 -- Washington D.C. PDF icon es40smith.pdf More Documents & Publications Molecular Dynamics Simulation Studies of Electrolytes ...

  20. Interoperable Technologies for Advanced Petascale Simulations...

    Office of Scientific and Technical Information (OSTI)

    We have simulated a step in the reprocessing and separation of spent fuels from nuclear power plant fuel rods. We have implemented the fluid-structure interaction for 3D windmill ...

  1. Posters Comparison Between General Circulation Model Simulation...

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

    GCM used for this study is from the Max-Planck Institute and the University of Hamburg, Germany (ECHAM3); it is described in detail by Roeckner et al. (1992). The simulation for...

  2. Running Parallel Discrete Event Simulators on Sierra

    SciTech Connect (OSTI)

    Barnes, P. D.; Jefferson, D. R.

    2015-12-03

    In this proposal we consider porting the ROSS/Charm++ simulator and the discrete event models that run under its control so that they run on the Sierra architecture and make efficient use of the Volta GPUs.

  3. Thermal Simulation of Advanced Powertrain Systems

    Broader source: Energy.gov [DOE]

    Under this project, the Volvo complete vehicle model was modified to include engine and exhaust system thermal outputs and cooling system to enable WHR simulations from a system perspective.

  4. Transportation System Simulation | Argonne National Laboratory

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

    Transportation System Simulation Transportation System Simulation Today's transportation systems are becoming more and more complex, with integration of communication technologies, vehicle automation and innovative mobility solutions. The advent of connected and autonomous vehicles (CAVs) will see no shortage of new technologies aimed at transforming transportation. While some will likely succeed and others fail, to truly understand their potential and their impacts on the larger transportation

  5. Sandia National Laboratories: Electromagnetic Environments Simulator (EMES)

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

    Electromagnetic Environments Simulator (EMES) The Electromagnetic Environments Simulator (EMES) is a large transverse electromagnetic (TEM) cell that propagates a uniform, planar electromagnetic wave through the cell volume where test items are placed. EMES can be used for continuous wave (CW) Electromagnetic Radiation (EMR) and transient Electromagnetic Pulse (EMP) testing. The electric field is vertically polarized between the center conductor and the floor. If it is desired to illuminate test

  6. modeling-and-simulation-with-ls-dyna

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

    Modeling and Simulation with LS-DYNAĀ®: INSIGHTS INTO MODELING WITH A GOAL OF PROVIDING CREDIBLE PREDICTIVE SIMULATIONS Feb. 11-12, 2010 Argonne TRACC Dr. Ronald F. Kulak Announcement pdficon small This email address is being protected from spambots. You need JavaScript enabled to view it. Most applications of LS-DYNA are for complex, and often combined, physics where nonlinearities due to large deformations and material response, including failure, are the norm. Often the goal of such

  7. Observations and simulations improve space weather models

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

    Observations improve space weather models Observations and simulations improve space weather models Researchers used data from the Van Allen Probes to improve a three-dimensional model created by Los Alamos scientists called DREAM3D. June 25, 2014 NASA's Van Allen Probes sample the Earth's magnetosphere. NASA's Van Allen Probes sample the Earth's magnetosphere. The work demonstrated that DREAM3D accurately simulated the behavior of a complex and dynamic event in the radiation belt that was

  8. Validation and Uncertainty Characterization for Energy Simulation

    Energy Savers [EERE]

    Validation and Uncertainty Characterization for Energy Simulation (#1530) Philip Haves (LBNL) Co-PI's: Ron Judkoff (NREL), Joshua New (ORNL), Ralph Muehleisen (ANL) BTO Merit Review - April 16/17, 2015 Model Discrepancy Experiment Simulation Problem Statement 2 Sources of differences: ļµ Uncertainty: ļ± model algorithms ļ± input parameters ļ± modeler decisions ļµ Variability: ļ± weather ļ± occupancy ļ± operation Source: Energy performance of LEED-NC buildings, NBI, 2008 as-built vs.

  9. Observations and simulations improve space weather models

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

    Observations improve space weather models Observations and simulations improve space weather models Researchers used data from the Van Allen Probes to improve a three-dimensional model created by Los Alamos scientists called DREAM3D. June 25, 2014 NASA's Van Allen Probes sample the Earth's magnetosphere. NASA's Van Allen Probes sample the Earth's magnetosphere. The work demonstrated that DREAM3D accurately simulated the behavior of a complex and dynamic event in the radiation belt that was

  10. Mesoscale Simulations of Coarsening in GB Networks

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

    Mukul Kumar is the Principal Investigator for Mesoscale Simulations of Coarsening in GB Networks LLNL BES Programs Highlight Mesoscale Simulations of Coarsening in GB Networks The Phase Field Model evolves a grain boundary network with realistic network correlations, as seeded by a group-theory-based Monte Carlo model M. Tang, B. W. Reed, and M. Kumar, J. Appl. Phys. 112, 043505 (2012) V. Bulatov, B. W. Reed, and M. Kumar; "Grain boundary energy function for FCC metals," Physical

  11. Molecular dynamics simulation studies of electrolytes and

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

    electrolyte/electrode interfaces | Department of Energy studies of electrolytes and electrolyte/electrode interfaces Molecular dynamics simulation studies of electrolytes and electrolyte/electrode interfaces 2009 DOE Hydrogen Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting, May 18-22, 2009 -- Washington D.C. PDF icon es_40_smith.pdf More Documents & Publications Molecular Dynamics Simulation Studies of Electrolytes and Electrolyte/Electrode

  12. Interoperable Technologies for Advanced Petascale Simulations (Technical

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

    Report) | SciTech Connect Technical Report: Interoperable Technologies for Advanced Petascale Simulations Citation Details In-Document Search Title: Interoperable Technologies for Advanced Petascale Simulations Our final report on the accomplishments of ITAPS at Stony Brook during period covered by the research award includes component service, interface service and applications. On the component service, we have designed and implemented a robust functionality for the Lagrangian tracking of

  13. 3-D simulations of multiple beam klystrons

    SciTech Connect (OSTI)

    Smithe, David N.; Bettenhausen, Mike; Ludeking, Larry; Caryotakis, G.; Sprehn, Daryl; Scheitrum, Glenn [Mission Research Corporation, 8560 Cinderbed Rd., Suite 700, Newington, Virginia 22122 (United States); Stanford Linear Accelerator Center, 2575 Sand Hill Rd., Menlo Park, California 94025 (United States)

    1999-05-07

    The MAGIC3D simulation code is being used to assess the multi-dimensional physics issues relating to the design and operation of multiple beam klystrons. Investigations, to date, include a detailed study of the mode structure of the cavities in the 19-beam hexagonally packed geometry and a study of the velocity spread caused by the cavity mode's field profile. Some attempts to minimize this effect are investigated. Additional simulations have provided quantification of the beam loading Q in a dual input cavity, and optimization of a dual output cavity. An important goal of the simulations is an accurate picture of beam transport along the length of the MBK. We have quantified the magnitude and spatial variation of the beam-line space charge interactions within a cavity gap. Present simulations have demonstrated the transport of the beam through three cavities (the present limits of our simulation size) without difficulty; additional length simulations are expected. We have also examined unbalanced beam-line scenarios, e.g., one beam-line suppressed, and find little disturbance to the transport in individual cavity tests, with results for multiple cavity transport expected.

  14. Role of Modeling and Simulation in Scientific Discovery | Department of

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

    Energy Role of Modeling and Simulation in Scientific Discovery Role of Modeling and Simulation in Scientific Discovery January 29, 2013 - 10:14am Addthis Role of Modeling and Simulation in Scientific Discovery What are the key facts? Modeling and simulation supplement theory and experimentation, improving the scientific method. Industry that has embraced modeling and simulation has realized huge savings in cost and time in getting thier products to market. Modeling and simulation should

  15. Communication Simulations for Power System Applications

    SciTech Connect (OSTI)

    Fuller, Jason C.; Ciraci, Selim; Daily, Jeffrey A.; Fisher, Andrew R.; Hauer, Matthew L.

    2013-05-29

    New smart grid technologies and concepts, such as dynamic pricing, demand response, dynamic state estimation, and wide area monitoring, protection, and control, are expected to require considerable communication resources. As the cost of retrofit can be high, future power grids will require the integration of high-speed, secure connections with legacy communication systems, while still providing adequate system control and security. While considerable work has been performed to create co-simulators for the power domain with load models and market operations, limited work has been performed in integrating communications directly into a power domain solver. The simulation of communication and power systems will become more important as the two systems become more inter-related. This paper will discuss ongoing work at Pacific Northwest National Laboratory to create a flexible, high-speed power and communication system co-simulator for smart grid applications. The framework for the software will be described, including architecture considerations for modular, high performance computing and large-scale scalability (serialization, load balancing, partitioning, cross-platform support, etc.). The current simulator supports the ns-3 (telecommunications) and GridLAB-D (distribution systems) simulators. Ongoing and future work will be described, including planned future expansions for a traditional transmission solver. A test case using the co-simulator, utilizing a transactive demand response system created for the Olympic Peninsula and AEP gridSMART demonstrations, requiring two-way communication between distributed and centralized market devices, will be used to demonstrate the value and intended purpose of the co-simulation environment.

  16. Sandia Energy - Molecular Dynamics Simulations Predict Fate of...

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

    Molecular Dynamics Simulations Predict Fate of Uranium in Sediments Home Highlights - Energy Research Molecular Dynamics Simulations Predict Fate of Uranium in Sediments Previous...

  17. ASCR Workshop on Turbulent Flow Simulations at the Exascale:...

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

    ASCR Workshop on Turbulent Flow Simulations at the Exascale: Opportunities and Challenges ASCR Workshop on Turbulent Flow Simulations at the Exascale: Opportunities and Challenges...

  18. Simulation Tools for Modeling Thermal Spallation Drilling on...

    Office of Scientific and Technical Information (OSTI)

    Simulation Tools for Modeling Thermal Spallation Drilling on Multiple Scales Citation Details In-Document Search Title: Simulation Tools for Modeling Thermal Spallation Drilling on ...

  19. Office Of Nuclear Energy Annual Review Meeting Dynamic Simulation...

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

    models with user friendly interfaces (Excel Web) allow common simulation environment ... PRISM (first) plant model completed n Excel Based Simulation Tool Completed (see ...

  20. ORNL). Consortium for Advanced Simulation of Light Water Reactors

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

    Simulation of Light Water Reactors (CASL) was established by the US Department of Energy in 2010 to advance modeling and simulation capabilities for nuclear reactors. CASL's...

  1. Sandia Energy - WEC-Sim (Wave Energy Converter SIMulator)

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

    WEC-Sim (Wave Energy Converter SIMulator) Home Stationary Power Energy Conversion Efficiency Water Power WEC-Sim (Wave Energy Converter SIMulator) WEC-Sim (Wave Energy Converter...

  2. Sandia Energy - Ice-Sheet Simulation Code Matures, Leveraging...

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

    and as the land ice component of coupled climate simulations in DOE's Earth System Model. The land ice component is responsible for simulating the evolution of the...

  3. A Holistic Approach to Modeling and Simulation for Resilience...

    Office of Scientific and Technical Information (OSTI)

    A Holistic Approach to Modeling and Simulation for Resilience and Power Configuration. Citation Details In-Document Search Title: A Holistic Approach to Modeling and Simulation for...

  4. NOx Adsorbers for Heavy Duty Truck Engines - Testing and Simulation...

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

    Adsorbers for Heavy Duty Truck Engines - Testing and Simulation NOx Adsorbers for Heavy Duty Truck Engines - Testing and Simulation This report provides the results of an ...

  5. Benchmarking of measurement and simulation of transverse rms...

    Office of Scientific and Technical Information (OSTI)

    Benchmarking of measurement and simulation of transverse rms-emittance growth Citation Details In-Document Search Title: Benchmarking of measurement and simulation of transverse ...

  6. Development of a model colloidal system for rheology simulation...

    Office of Scientific and Technical Information (OSTI)

    Development of a model colloidal system for rheology simulation. Citation Details In-Document Search Title: Development of a model colloidal system for rheology simulation. You...

  7. Development of Numerical Simulation Capabilities for In Situ...

    Office of Scientific and Technical Information (OSTI)

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

  8. Electro-thermal-mechanical Simulation and Reliability for Plug...

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

    More Documents & Publications Electro-thermal-mechanical Simulation and Reliability for Plug-in Vehicle Converters and Inverters Electro-thermal-mechanical Simulation...

  9. PROJECT PROFILE: Rapid QSTS Simulations for High-Resolution Comprehens...

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

    This project will accelerate QSTS simulation using methods such as event-based simulation, linear power flow approximation, parallel processing of power flow solutions separable by ...

  10. An Integrated Platform for Engine Performance Simulations and...

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

    An Integrated Platform for Engine Performance Simulations and Optimization under Diesel Conditions The direct injection stochastic reactor model is capable of accurate simulation ...

  11. Numerical simulations for low energy nuclear reactions including...

    Office of Scientific and Technical Information (OSTI)

    Numerical simulations for low energy nuclear reactions including direct channels to validate statistical models Citation Details In-Document Search Title: Numerical simulations for...

  12. Simulation and Theory of Ions at Atmospherically Relevant Aqueous...

    Office of Scientific and Technical Information (OSTI)

    Simulation and Theory of Ions at Atmospherically Relevant Aqueous Liquid-Air Interfaces Citation Details In-Document Search Title: Simulation and Theory of Ions at Atmospherically...

  13. Los Alamos computer simulation improves offshore drill rig safety

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

    March 24, 2015 A simulation of vortex induced motion shows how ocean currents affect offshore oil rigs. A simulation of vortex induced motion shows how ocean currents affect ...

  14. ACCOLADES: A Scalable Workflow Framework for Large-Scale Simulation...

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

    ACCOLADES: A Scalable Workflow Framework for Large-Scale Simulation and Analyses of Automotive Engines Title ACCOLADES: A Scalable Workflow Framework for Large-Scale Simulation and...

  15. Energy Efficient Biomolecular Simulations with FPGA-based Reconfigurab...

    Office of Scientific and Technical Information (OSTI)

    Energy Efficient Biomolecular Simulations with FPGA-based Reconfigurable Computing Citation Details In-Document Search Title: Energy Efficient Biomolecular Simulations with...

  16. Home Energy Score Update: New Simulation Training and Credential...

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

    Update: New Simulation Training and Credential Requirements for Assessors Home Energy Score Update: New Simulation Training and Credential Requirements for Assessors Home Energy...

  17. Computer Simulations Indicate Calcium Carbonate Has a Dense Liquid...

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

    Computer Simulations Indicate Calcium Carbonate Has a Dense Liquid Phase Computer Simulations Indicate Calcium Carbonate Has a Dense Liquid Phase Berkeley Lab research could help...

  18. Level-2 Milestone 4468: Lorenz Simulation Interface Beta Release...

    Office of Scientific and Technical Information (OSTI)

    Level-2 Milestone 4468: Lorenz Simulation Interface Beta Release Citation Details In-Document Search Title: Level-2 Milestone 4468: Lorenz Simulation Interface Beta Release You...

  19. 3-D Combustion Simulation Strategy Status, Future Potential,...

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

    Combustion Simulation Strategy Status, Future Potential, and Application Issues 3-D Combustion Simulation Strategy Status, Future Potential, and Application Issues 2004 Diesel...

  20. Other: Multiscale Simulation of Blood Flow in Brain Arteries...

    Office of Scientific and Technical Information (OSTI)

    Other: Multiscale Simulation of Blood Flow in Brain Arteries with an Aneurysm Citation Details Title: Multiscale Simulation of Blood Flow in Brain Arteries with an Aneurysm

  1. Overview of Vehicle and Systems Simulation and Testing | Department...

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

    s000slezak2012o.pdf More Documents & Publications Overview of Vehicle and Systems Simulation and Testing Overview of Vehicle and Systems Simulation and Testing Vehicle...

  2. Vehicle Technologies Office: 2014 Vehicle and Systems Simulation...

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

    Vehicle and Systems Simulation and Testing Annual Progress Report Vehicle Technologies Office: 2014 Vehicle and Systems Simulation and Testing Annual Progress Report The Vehicle...

  3. Trillion Particle Simulation on Hopper Honored with Best Paper

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

    Trillion Particle Simulation on Hopper Honored with Best Paper Trillion Particle Simulation on Hopper Honored with Best Paper Berkeley Lab Researchers Bridge Gap to Exascale May...

  4. Post Fukushima tsunami simulations for Malaysian coasts

    SciTech Connect (OSTI)

    Koh, Hock Lye; Teh, Su Yean; Abas, Mohd Rosaidi Che

    2014-10-24

    The recent recurrences of mega tsunamis in the Asian region have rekindled concern regarding potential tsunamis that could inflict severe damage to affected coastal facilities and communities. The 11 March 2011 Fukushima tsunami that crippled nuclear power plants in Northern Japan has further raised the level of caution. The recent discovery of petroleum reserves in the coastal water surrounding Malaysia further ignites the concern regarding tsunami hazards to petroleum facilities located along affected coasts. Working in a group, federal government agencies seek to understand the dynamics of tsunami and their impacts under the coordination of the Malaysian National Centre for Tsunami Research, Malaysian Meteorological Department. Knowledge regarding the generation, propagation and runup of tsunami would provide the scientific basis to address safety issues. An in-house tsunami simulation models known as TUNA has been developed by the authors to assess tsunami hazards along affected beaches so that mitigation measures could be put in place. Capacity building on tsunami simulation plays a critical role in the development of tsunami resilience. This paper aims to first provide a simple introduction to tsunami simulation towards the achievement of tsunami simulation capacity building. The paper will also present several scenarios of tsunami dangers along affected Malaysia coastal regions via TUNA simulations to highlight tsunami threats. The choice of tsunami generation parameters reflects the concern following the Fukushima tsunami.

  5. Geochemical Reaction Mechanism Discovery from Molecular Simulation

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

    Stack, Andrew G.; Kent, Paul R. C.

    2014-11-10

    Methods to explore reactions using computer simulation are becoming increasingly quantitative, versatile, and robust. In this review, a rationale for how molecular simulation can help build better geochemical kinetics models is first given. We summarize some common methods that geochemists use to simulate reaction mechanisms, specifically classical molecular dynamics and quantum chemical methods and discuss their strengths and weaknesses. Useful tools such as umbrella sampling and metadynamics that enable one to explore reactions are discussed. Several case studies wherein geochemists have used these tools to understand reaction mechanisms are presented, including water exchange and sorption on aqueous species and mineralmoreĀ Ā» surfaces, surface charging, crystal growth and dissolution, and electron transfer. The impact that molecular simulation has had on our understanding of geochemical reactivity are highlighted in each case. In the future, it is anticipated that molecular simulation of geochemical reaction mechanisms will become more commonplace as a tool to validate and interpret experimental data, and provide a check on the plausibility of geochemical kinetic models.Ā«Ā less

  6. Proline puckering parameters for collagen structure simulations

    SciTech Connect (OSTI)

    Wu, Di

    2015-03-15

    Collagen is made of triple helices rich in proline residues, and hence is influenced by the conformational motions of prolines. Because the backbone motions of prolines are restricted by the helical structures, the only side chain motionā€”proline puckeringā€”becomes an influential factor that may affect the stability of collagen structures. In molecular simulations, a proper proline puckering population is desired so to yield valid results of the collagen properties. Here we design the proline puckering parameters in order to yield suitable proline puckering populations as demonstrated in the experimental results. We test these parameters in collagen and the proline dipeptide simulations. Compared with the results of the PDB and the quantum calculations, we propose the proline puckering parameters for the selected collagen model simulations.

  7. LHC RF System Time-Domain Simulation

    SciTech Connect (OSTI)

    Mastorides, T.; Rivetta, C.

    2010-09-14

    Non-linear time-domain simulations have been developed for the Positron-Electron Project (PEP-II) and the Large Hadron Collider (LHC). These simulations capture the dynamic behavior of the RF station-beam interaction and are structured to reproduce the technical characteristics of the system (noise contributions, non-linear elements, and more). As such, they provide useful results and insight for the development and design of future LLRF feedback systems. They are also a valuable tool for the study of diverse longitudinal beam dynamics effects such as coupled-bunch impedance driven instabilities and single bunch longitudinal emittance growth. Results from these studies and related measurements from PEP-II and LHC have been presented in multiple places. This report presents an example of the time-domain simulation implementation for the LHC.

  8. An optical simulation of shared memory

    SciTech Connect (OSTI)

    Goldberg, L.A.; Matias, Y.; Rao, S.

    1994-06-01

    We present a work-optimal randomized algorithm for simulating a shared memory machine (PRAM) on an optical communication parallel computer (OCPC). The OCPC model is motivated by the potential of optical communication for parallel computation. The memory of an OCPC is divided into modules, one module per processor. Each memory module only services a request on a timestep if it receives exactly one memory request. Our algorithm simulates each step of an n lg lg n-processor EREW PRAM on an n-processor OCPC in O(lg lg n) expected delay. (The probability that the delay is longer than this is at most n{sup {minus}{alpha}} for any constant {alpha}). The best previous simulation, due to Valiant, required {Theta}(lg n) expected delay.

  9. Numerical simulations of strong incompressible magnetohydrodynamic turbulence

    SciTech Connect (OSTI)

    Mason, J.; Cattaneo, F.; Perez, J. C.; Boldyrev, S.

    2012-05-15

    Magnetised plasma turbulence pervades the universe and is likely to play an important role in a variety of astrophysical settings. Magnetohydrodynamics (MHD) provides the simplest theoretical framework in which phenomenological models for the turbulent dynamics can be built. Numerical simulations of MHD turbulence are widely used to guide and test the theoretical predictions; however, simulating MHD turbulence and accurately measuring its scaling properties is far from straightforward. Computational power limits the calculations to moderate Reynolds numbers and often simplifying assumptions are made in order that a wider range of scales can be accessed. After describing the theoretical predictions and the numerical approaches that are often employed in studying strong incompressible MHD turbulence, we present the findings of a series of high-resolution direct numerical simulations. We discuss the effects that insufficiencies in the computational approach can have on the solution and its physical interpretation.

  10. Crashworthiness simulations with DYNA3D

    SciTech Connect (OSTI)

    Schauer, D.A.; Hoover, C.G.; Kay, G.J.; Lee, A.S.; De Groot, A.J.

    1996-04-01

    Current progress in parallel algorithm research and applications in vehicle crash simulation is described for the explicit, finite element algorithms in DYNA3D. Problem partitioning methods and parallel algorithms for contact at material interfaces are the two challenging algorithm research problems that are addressed. Two prototype parallel contact algorithms have been developed for treating the cases of local and arbitrary contact. Demonstration problems for local contact are crashworthiness simulations with 222 locally defined contact surfaces and a vehicle/barrier collision modeled with arbitrary contact. A simulation of crash tests conducted for a vehicle impacting a U-channel small sign post embedded in soil has been run on both the serial and parallel versions of DYNA3D. A significant reduction in computational time has been observed when running these problems on the parallel version. However, to achieve maximum efficiency, complex problems must be appropriately partitioned, especially when contact dominates the computation.

  11. Multi-physics microstructural simulation of sintering.

    SciTech Connect (OSTI)

    Tikare, Veena

    2010-06-01

    Simulating the detailed evolution of microstructure at the mesoscale is increasingly being addressed by a number of methods. Discrete element modeling and Potts kinetic Monte Carlo have achieved success in capturing different aspects of sintering well. Discrete element cannot treat the details of neck formation and other shape evolution, especially when considering particles of arbitrary shapes. Potts kMC treats the micorstructural evolution very well, but cannot incorporate complex stress states that form especially during differential sintering. A model that is capable of simulating microstructural evolution during sintering at the mesoscale and can incorporate differential stresses is being developed. This multi-physics model that can treat both interfacial energies and the inter-particle stresses will be introduced. It will be applied to simulate microstructural evolution while resolving individual particles and the stresses that develop between them due to local shrinkage. Results will be presented and the future development of this model will be discussed.

  12. Xyce parallel electronic simulator : users' guide.

    SciTech Connect (OSTI)

    Mei, Ting; Rankin, Eric Lamont; Thornquist, Heidi K.; Santarelli, Keith R.; Fixel, Deborah A.; Coffey, Todd Stirling; Russo, Thomas V.; Schiek, Richard Louis; Warrender, Christina E.; Keiter, Eric Richard; Pawlowski, Roger Patrick

    2011-05-01

    This manual describes the use of the Xyce Parallel Electronic Simulator. Xyce has been designed as a SPICE-compatible, high-performance analog circuit simulator, and has been written to support the simulation needs of the Sandia National Laboratories electrical designers. This development has focused on improving capability over the current state-of-the-art in the following areas: (1) Capability to solve extremely large circuit problems by supporting large-scale parallel computing platforms (up to thousands of processors). Note that this includes support for most popular parallel and serial computers; (2) Improved performance for all numerical kernels (e.g., time integrator, nonlinear and linear solvers) through state-of-the-art algorithms and novel techniques. (3) Device models which are specifically tailored to meet Sandia's needs, including some radiation-aware devices (for Sandia users only); and (4) Object-oriented code design and implementation using modern coding practices that ensure that the Xyce Parallel Electronic Simulator will be maintainable and extensible far into the future. Xyce is a parallel code in the most general sense of the phrase - a message passing parallel implementation - which allows it to run efficiently on the widest possible number of computing platforms. These include serial, shared-memory and distributed-memory parallel as well as heterogeneous platforms. Careful attention has been paid to the specific nature of circuit-simulation problems to ensure that optimal parallel efficiency is achieved as the number of processors grows. The development of Xyce provides a platform for computational research and development aimed specifically at the needs of the Laboratory. With Xyce, Sandia has an 'in-house' capability with which both new electrical (e.g., device model development) and algorithmic (e.g., faster time-integration methods, parallel solver algorithms) research and development can be performed. As a result, Xyce is a unique electrical simulation capability, designed to meet the unique needs of the laboratory.

  13. Terascale High-Fidelity Simulations of Turbulent Combustion with Detailed Chemistry: Spray Simulations

    SciTech Connect (OSTI)

    Rutland, Christopher J.

    2009-04-26

    The Terascale High-Fidelity Simulations of Turbulent Combustion (TSTC) project is a multi-university collaborative effort to develop a high-fidelity turbulent reacting flow simulation capability utilizing terascale, massively parallel computer technology. The main paradigm of the approach is direct numerical simulation (DNS) featuring the highest temporal and spatial accuracy, allowing quantitative observations of the fine-scale physics found in turbulent reacting flows as well as providing a useful tool for development of sub-models needed in device-level simulations. Under this component of the TSTC program the simulation code named S3D, developed and shared with coworkers at Sandia National Laboratories, has been enhanced with new numerical algorithms and physical models to provide predictive capabilities for turbulent liquid fuel spray dynamics. Major accomplishments include improved fundamental understanding of mixing and auto-ignition in multi-phase turbulent reactant mixtures and turbulent fuel injection spray jets.

  14. Nonlinear simulations to optimize magnetic nanoparticle hyperthermia

    SciTech Connect (OSTI)

    Reeves, Daniel B. Weaver, John B.

    2014-03-10

    Magnetic nanoparticle hyperthermia is an attractive emerging cancer treatment, but the acting microscopic energy deposition mechanisms are not well understood and optimization suffers. We describe several approximate forms for the characteristic time of Néel rotations with varying properties and external influences. We then present stochastic simulations that show agreement between the approximate expressions and the micromagnetic model. The simulations show nonlinear imaginary responses and associated relaxational hysteresis due to the field and frequency dependencies of the magnetization. This suggests that efficient heating is possible by matching fields to particles instead of resorting to maximizing the power of the applied magnetic fields.

  15. SLUDGE BATCH 6 PHASE II FLOWSHEET SIMULATIONS

    SciTech Connect (OSTI)

    Koopman, D.; Best, D.

    2010-03-30

    Two Sludge Receipt and Adjustment Tank (SRAT) runs were used to demonstrate that a fairly wide window of acid stoichiometry was available for processing SB6 Phase II flowsheet simulant (Tank 40 simulant) while still meeting the dual goals of acceptable nitrate destruction and controlled hydrogen generation. Phase II was an intermediate flowsheet study for the projected composition of Tank 40 after transfer of SB6/Tank 51 sludge to the heel of SB5. The composition was based on August 2009 projections. A window of about 50% in total acid was found between acceptable nitrite destruction and excessive hydrogen generation.

  16. Simulations Reveal Unusual Death for Ancient Stars

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

    Simulations Reveal Unusual Death for Ancient Stars Simulations Reveal Unusual Death for Ancient Stars Findings made possible with NERSC resources and Berkeley Lab Code September 29, 2014 Contact: Linda Vu, +1 510 495 2402, lvu@lbl.gov SMSweb.jpg This image is a slice through the interior of a supermassive star of 55,500 solar masses along the axis of symmetry. It shows the inner helium core in which nuclear burning is converting helium to oxygen, powering various fluid instabilities (swirling

  17. Monte Carlo simulation for the transport beamline

    SciTech Connect (OSTI)

    Romano, F.; Cuttone, G.; Jia, S. B.; Varisano, A.; Attili, A.; Marchetto, F.; Russo, G.; Cirrone, G. A. P.; Schillaci, F.; Scuderi, V.; Carpinelli, M.

    2013-07-26

    In the framework of the ELIMED project, Monte Carlo (MC) simulations are widely used to study the physical transport of charged particles generated by laser-target interactions and to preliminarily evaluate fluence and dose distributions. An energy selection system and the experimental setup for the TARANIS laser facility in Belfast (UK) have been already simulated with the GEANT4 (GEometry ANd Tracking) MC toolkit. Preliminary results are reported here. Future developments are planned to implement a MC based 3D treatment planning in order to optimize shots number and dose delivery.

  18. Xyce parallel electronic simulator release notes.

    SciTech Connect (OSTI)

    Keiter, Eric Richard; Hoekstra, Robert John; Mei, Ting; Russo, Thomas V.; Schiek, Richard Louis; Thornquist, Heidi K.; Rankin, Eric Lamont; Coffey, Todd Stirling; Pawlowski, Roger Patrick; Santarelli, Keith R.

    2010-05-01

    The Xyce Parallel Electronic Simulator has been written to support, in a rigorous manner, the simulation needs of the Sandia National Laboratories electrical designers. Specific requirements include, among others, the ability to solve extremely large circuit problems by supporting large-scale parallel computing platforms, improved numerical performance and object-oriented code design and implementation. The Xyce release notes describe: Hardware and software requirements New features and enhancements Any defects fixed since the last release Current known defects and defect workarounds For up-to-date information not available at the time these notes were produced, please visit the Xyce web page at http://www.cs.sandia.gov/xyce.

  19. Parallel Performance of a Combustion Chemistry Simulation

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

    Skinner, Gregg; Eigenmann, Rudolf

    1995-01-01

    We used a description of a combustion simulation's mathematical and computational methods to develop a version for parallel execution. The result was a reasonable performance improvement on small numbers of processors. We applied several important programming techniques, which we describe, in optimizing the application. This work has implications for programming languages, compiler design, and software engineering.

  20. Design and Simulation of Hybridization Experiments

    Energy Science and Technology Software Center (OSTI)

    1995-11-28

    DB EXP DESIGN is a suite of three UNIX shell-like programs, DWC which computes oligomer composition of DNA texts using directed acyclic word data structures; DWO, which simulates hybridization experiments; and DMI, which calculates the information contenet of individual probes, their mutual information content, and their joint information content through estimation of Markov trees.

  1. EM Leads with Advanced Simulation Capability Technology

    Broader source: Energy.gov [DOE]

    WASHINGTON, D.C. ā€“ Since 2010, EMā€™s Office of Soil and Groundwater Remediation has initiated technology development programs such as the Advanced Simulation Capability for Environmental Management (ASCEM) and the Applied Field Research Initiatives to enhance characterization and remediation technologies and create cost savings.

  2. A Hierarchical Evaluation of Regional Climate Simulations

    SciTech Connect (OSTI)

    Leung, Lai-Yung R.; Ringler, Todd; Collins, William D.; Taylor, Mark; Ashfaq, Moetasim

    2013-08-20

    Global climate models (GCMs) are the primary tools for predicting the evolution of the climate system. Through decades of development, GCMs have demonstrated useful skill in simulating climate at continental to global scales. However, large uncertainties remain in projecting climate change at regional scales, which limit our ability to inform decisions on climate change adaptation and mitigation. To bridge this gap, different modeling approaches including nested regional climate models (RCMs), global stretch-grid models, and global high-resolution atmospheric models have been used to provide regional climate simulations (Leung et al. 2003). In previous efforts to evaluate these approaches, isolating their relative merits was not possible because factors such as dynamical frameworks, physics parameterizations, and model resolutions were not systematically constrained. With advances in high performance computing, it is now feasible to run coupled atmosphere-ocean GCMs at horizontal resolution comparable to what RCMs use today. Global models with local refinement using unstructured grids have become available for modeling regional climate (e.g., Rauscher et al. 2012; Ringler et al. 2013). While they offer opportunities to improve climate simulations, significant efforts are needed to test their veracity for regional-scale climate simulations.

  3. Xyce parallel electronic simulator : reference guide.

    SciTech Connect (OSTI)

    Mei, Ting; Rankin, Eric Lamont; Thornquist, Heidi K.; Santarelli, Keith R.; Fixel, Deborah A.; Coffey, Todd Stirling; Russo, Thomas V.; Schiek, Richard Louis; Warrender, Christina E.; Keiter, Eric Richard; Pawlowski, Roger Patrick

    2011-05-01

    This document is a reference guide to the Xyce Parallel Electronic Simulator, and is a companion document to the Xyce Users Guide. The focus of this document is (to the extent possible) exhaustively list device parameters, solver options, parser options, and other usage details of Xyce. This document is not intended to be a tutorial. Users who are new to circuit simulation are better served by the Xyce Users Guide. The Xyce Parallel Electronic Simulator has been written to support, in a rigorous manner, the simulation needs of the Sandia National Laboratories electrical designers. It is targeted specifically to run on large-scale parallel computing platforms but also runs well on a variety of architectures including single processor workstations. It also aims to support a variety of devices and models specific to Sandia needs. This document is intended to complement the Xyce Users Guide. It contains comprehensive, detailed information about a number of topics pertinent to the usage of Xyce. Included in this document is a netlist reference for the input-file commands and elements supported within Xyce; a command line reference, which describes the available command line arguments for Xyce; and quick-references for users of other circuit codes, such as Orcad's PSpice and Sandia's ChileSPICE.

  4. Fusion Simulation Program Definition. Final report

    SciTech Connect (OSTI)

    Cary, John R.

    2012-09-05

    We have completed our contributions to the Fusion Simulation Program Definition Project. Our contributions were in the overall planning with concentration in the definition of the area of Software Integration and Support. We contributed to the planning of multiple meetings, and we contributed to multiple planning documents.

  5. Multiphysics Object-Oriented Simulation Environment (MOOSE)

    ScienceCinema (OSTI)

    None

    2013-05-28

    Nuclear reactor operators can expand safety margins with more precise information about how materials behave inside operating reactors. INL's new simulation platform makes such studies easier & more informative by letting researchers "plug-n-play" their mathematical models, skipping years of computer code development.

  6. Vehicle & Systems Simulation & Testing

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

    Sustainable Transportation Vehicle & Systems Simulation & Testing Lee Slezak, David Anderson June 16, 2014 2 Outline * Goals and Objectives * Challenges and Strategy * Current Portfolio * Strategies * Sample Project Targets & Objectives * Budget * Accomplishments * 2013 Progress * Collaborations * Competitively Awarded Projects * Summary * Contacts 3 Goals and Objectives Accelerate market penetration of advanced vehicles and systems to displace petroleum consumption, reduce GHG

  7. Advanced Simulation and Computing Business Plan

    SciTech Connect (OSTI)

    Rummel, E.

    2015-07-09

    To maintain a credible nuclear weapons program, the National Nuclear Security Administrationā€™s (NNSAā€™s) Office of Defense Programs (DP) needs to make certain that the capabilities, tools, and expert staff are in place and are able to deliver validated assessments. This requires a complete and robust simulation environment backed by an experimental program to test ASC Program models. This ASC Business Plan document encapsulates a complex set of elements, each of which is essential to the success of the simulation component of the Nuclear Security Enterprise. The ASC Business Plan addresses the hiring, mentoring, and retaining of programmatic technical staff responsible for building the simulation tools of the nuclear security complex. The ASC Business Plan describes how the ASC Program engages with industry partnersā€”partners upon whom the ASC Program relies on for todayā€™s and tomorrowā€™s high performance architectures. Each piece in this chain is essential to assure policymakers, who must make decisions based on the results of simulations, that they are receiving all the actionable information they need.

  8. Center for Advanced Modeling and Simulation Intern

    ScienceCinema (OSTI)

    Gertman, Vanessa

    2013-05-28

    Some interns just copy papers and seal envelopes. Not at INL! Check out how Vanessa Gertman, an INL intern working at the Center for Advanced Modeling and Simulation, spent her summer working with some intense visualization software. Lots more content like this is available at INL's facebook page http://www.facebook.com/idahonationallaboratory.

  9. Simulation and Risk Assessment for Carbon Storage | Department of Energy

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

    Carbon Capture and Storage Ā» Simulation and Risk Assessment for Carbon Storage Simulation and Risk Assessment for Carbon Storage Research in simulation and risk assessment is focused on development of advanced simulation models of the subsurface and integration of the results into a risk assessment that includes both technical and programmatic risks. Simulation models are critical for predicting the flow of the CO2 in the target formations, chemical changes that may occur in the reservoir, and

  10. LANL researchers simulate helium bubble behavior in fusion reactors

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

    Researchers simulate helium bubble behavior LANL researchers simulate helium bubble behavior in fusion reactors A team performed simulations to understand more fully how tungsten behaves in such harsh conditions, particularly in the presence of implanted helium that forms bubbles in the material. August 4, 2015 Simulation snapshots of the helium bubble just before bursting. Colors indicate tungsten atoms (red) and helium atoms (blue). Simulation snapshots of the helium bubble just before

  11. Advanced ST Plasma Scenario Simulations for NSTX

    SciTech Connect (OSTI)

    C.E. Kessel; E.J. Synakowski; D.A. Gates; R.W. Harvey; S.M. Kaye; T.K. Mau; J. Menard; C.K. Phillips; G. Taylor; R. Wilson; the NSTX Research Team

    2004-10-28

    Integrated scenario simulations are done for NSTX [National Spherical Torus Experiment] that address four primary milestones for developing advanced ST configurations: high {beta} and high {beta}{sub N} inductive discharges to study all aspects of ST physics in the high-beta regime; non-inductively sustained discharges for flattop times greater than the skin time to study the various current-drive techniques; non-inductively sustained discharges at high {beta} for flattop times much greater than a skin time which provides the integrated advanced ST target for NSTX; and non-solenoidal start-up and plasma current ramp-up. The simulations done here use the Tokamak Simulation Code (TSC) and are based on a discharge 109070. TRANSP analysis of the discharge provided the thermal diffusivities for electrons and ions, the neutral-beam (NB) deposition profile, and other characteristics. CURRAY is used to calculate the High Harmonic Fast Wave (HHFW) heating depositions and current drive. GENRAY/CQL3D is used to establish the heating and CD [current drive] deposition profiles for electron Bernstein waves (EBW). Analysis of the ideal-MHD stability is done with JSOLVER, BALMSC, and PEST2. The simulations indicate that the integrated advanced ST plasma is reachable, obtaining stable plasmas with {beta} {approx} 40% at {beta}{sub N}'s of 7.7-9, I{sub P} = 1.0 MA, and B{sub T} = 0.35 T. The plasma is 100% non-inductive and has a flattop of 4 skin times. The resulting global energy confinement corresponds to a multiplier of H{sub 98(y,2)} = 1.5. The simulations have demonstrated the importance of HHFW heating and CD, EBW off-axis CD, strong plasma shaping, density control, and early heating/H-mode transition for producing and optimizing these plasma configurations.

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

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

    Plimpton, Steve; Thompson, Aidan; Crozier, Paul

    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.

  13. The Integrated Plasma Simulator: A Flexible Python Framework for Coupled Multiphysics Simulation

    SciTech Connect (OSTI)

    Foley, Samantha S [ORNL; Elwasif, Wael R [ORNL; Bernholdt, David E [ORNL

    2011-11-01

    High-fidelity coupled multiphysics simulations are an increasingly important aspect of computational science. In many domains, however, there has been very limited experience with simulations of this sort, therefore research in coupled multiphysics often requires computational frameworks with significant flexibility to respond to the changing directions of the physics and mathematics. This paper presents the Integrated Plasma Simulator (IPS), a framework designed for loosely coupled simulations of fusion plasmas. The IPS provides users with a simple component architecture into which a wide range of existing plasma physics codes can be inserted as components. Simulations can take advantage of multiple levels of parallelism supported in the IPS, and can be controlled by a high-level ``driver'' component, or by other coordination mechanisms, such as an asynchronous event service. We describe the requirements and design of the framework, and how they were implemented in the Python language. We also illustrate the flexibility of the framework by providing examples of different types of simulations that utilize various features of the IPS.

  14. Synchrotron-based EUV lithography illuminator simulator

    DOE Patents [OSTI]

    Naulleau, Patrick P.

    2004-07-27

    A lithographic illuminator to illuminate a reticle to be imaged with a range of angles is provided. The illumination can be employed to generate a pattern in the pupil of the imaging system, where spatial coordinates in the pupil plane correspond to illumination angles in the reticle plane. In particular, a coherent synchrotron beamline is used along with a potentially decoherentizing holographic optical element (HOE), as an experimental EUV illuminator simulation station. The pupil fill is completely defined by a single HOE, thus the system can be easily modified to model a variety of illuminator fill patterns. The HOE can be designed to generate any desired angular spectrum and such a device can serve as the basis for an illuminator simulator.

  15. Simulating Biomolecules on the Petascale Supercomputers

    SciTech Connect (OSTI)

    Alam, Sadaf R [ORNL; Agarwal, Pratul K [ORNL; Geist, Al [ORNL

    2007-11-01

    Computing continues to make a signicant impact on biology. A variety of computational techniques have allowed rapid developments in design of experiments as well as collection, storage and analysis of experimental data. These developments have and are leading to novel insights into a variety of biological processes. The strength of computing in biology, however, comes from the ability to investigate those aspects of biological processes that are either dicult or are beyond the reach of experimental techniques. Particularly in the last 3 decades, availability of increasing computing power has had a signicant impact on the fundamental understanding of the biomolecules at the molecular level. Molecular biochemists and biophysicists, through theoretical multi-scale modeling and computational simulations, have been able to obtain atomistic level understanding of biomolecular structure, dynamics, folding and function. The protein folding problem, in particular, has attracted considerable interest from a variety of researchers and simulation scientists.

  16. Forcing continuous reconnection in hybrid simulations

    SciTech Connect (OSTI)

    Laitinen, T. V. Janhunen, P.; Jarvinen, R.; Kallio, E.

    2014-07-15

    We have performed hybrid simulations of driven continuous reconnection with open boundary conditions. Reconnection is started by a collision of two subsonic plasma fronts with opposite magnetic fields, without any specified magnetic field configuration as initial condition. Due to continued forced plasma inflow, a current sheet co-located with a dense and hot plasma sheet develops. The translational symmetry of the current sheet is broken by applying a spatial gradient in the inflow speed. We compare runs with and without localized resistivity: reconnection is initiated in both cases, but localized resistivity stabilizes it and enhances its efficiency. The outflow speed reaches about half of Alfvén speed. We quantify the conversion of magnetic energy to kinetic energy of protons and to Joule heating and show that with localized resistivity, kinetic energy of protons is increased on average five-fold in the reconnection in our simulation case.

  17. Boundary Plasma Turbulence Simulations for Tokamaks

    SciTech Connect (OSTI)

    Xu, X.; Umansky, M.; Dudson, B.; Snyder, P

    2008-05-15

    The boundary plasma turbulence code BOUT models tokamak boundary-plasma turbulence in a realistic divertor geometry using modified Braginskii equations for plasma vorticity, density (ni), electron and ion temperature (T{sub e}; T{sub i}) and parallel momenta. The BOUT code solves for the plasma fluid equations in a three dimensional (3D) toroidal segment (or a toroidal wedge), including the region somewhat inside the separatrix and extending into the scrape-off layer; the private flux region is also included. In this paper, a description is given of the sophisticated physical models, innovative numerical algorithms, and modern software design used to simulate edge-plasmas in magnetic fusion energy devices. The BOUT code's unique capabilities and functionality are exemplified via simulations of the impact of plasma density on tokamak edge turbulence and blob dynamics.

  18. Geometric Modeling, Radiation Simulation, Rendering, Analysis Package

    Energy Science and Technology Software Center (OSTI)

    1995-01-17

    RADIANCE is intended to aid lighting designers and architects by predicting the light levels and appearance of a space prior to construction. The package includes programs for modeling and translating scene geometry, luminaire data and material properties, all of which are needed as input to the simulation. The lighting simulation itself uses ray tracing techniques to compute radiance values (ie. the quantity of light passing through a specific point in a specific direction), which aremoreĀ Ā» typically arranged to form a photographic quality image. The resulting image may be analyzed, displayed and manipulated within the package, and converted to other popular image file formats for export to other packages, facilitating the production of hard copy output.Ā«Ā less

  19. Muon Simulation at the Daya Bay SIte

    SciTech Connect (OSTI)

    Mengyun, Guan; Jun, Cao; Changgen, Yang; Yaxuan, Sun; Luk, Kam-Biu

    2006-05-23

    With a pretty good-resolution mountain profile, we simulated the underground muon background at the Daya Bay site. To get the sea-level muon flux parameterization, a modification to the standard Gaisser's formula was introduced according to the world muon data. MUSIC code was used to transport muon through the mountain rock. To deploy the simulation, first we generate a statistic sample of sea-level muon events according to the sea-level muon flux distribution formula; then calculate the slant depth of muon passing through the mountain using an interpolation method based on the digitized data of the mountain; finally transport muons through rock to get underground muon sample, from which we can get results of muon flux, mean energy, energy distribution and angular distribution.

  20. Future Directions in Simulating Solar Geoengineering

    SciTech Connect (OSTI)

    Kravitz, Benjamin S.; Robock, Alan; Boucher, Olivier

    2014-08-05

    Solar geoengineering is a proposed set of technologies to temporarily alleviate some of the consequences of anthropogenic greenhouse gas emissions. The Geoengineering Model Intercomparison Project (GeoMIP) created a framework of geoengineering simulations in climate models that have been performed by modeling centers throughout the world (B. Kravitz et al., The Geoengineering Model Intercomparison Project (GeoMIP), Atmospheric Science Letters, 12(2), 162-167, doi:10.1002/asl.316, 2011). These experiments use state-of-the-art climate models to simulate solar geoengineering via uniform solar reduction, creation of stratospheric sulfate aerosol layers, or injecting sea spray into the marine boundary layer. GeoMIP has been quite successful in its mission of revealing robust features and key uncertainties of the modeled effects of solar geoengineering.

  1. National Infrastructure Simulation and Analysis Center Overview

    SciTech Connect (OSTI)

    Berscheid, Alan P.

    2012-07-30

    National Infrastructure Simulation and Analysis Center (NISAC) mission is to: (1) Improve the understanding, preparation, and mitigation of the consequences of infrastructure disruption; (2) Provide a common, comprehensive view of U.S. infrastructure and its response to disruptions - Scale & resolution appropriate to the issues and All threats; and (3) Built an operations-tested DHS capability to respond quickly to urgent infrastructure protection issues.

  2. best simulation techniques to optimize future scramjets

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

    simulation techniques to optimize future scramjets - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste

  3. Linac Coherent Light Source Monte Carlo Simulation

    Energy Science and Technology Software Center (OSTI)

    2006-03-15

    This suite consists of codes to generate an initial x-ray photon distribution and to propagate the photons through various objects. The suite is designed specifically for simulating the Linac Coherent Light Source, and x-ray free electron laser (XFEL) being built at the Stanford Linear Accelerator Center. The purpose is to provide sufficiently detailed characteristics of the laser to engineers who are designing the laser diagnostics.

  4. WEC-Sim (Wave Energy Converter SIMulator)

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

    (Wave Energy Converter SIMulator) - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management Programs

  5. Numerical recipes for mold filling simulation

    SciTech Connect (OSTI)

    Kothe, D.; Juric, D.; Lam, K.; Lally, B.

    1998-07-01

    Has the ability to simulate the filling of a mold progressed to a point where an appropriate numerical recipe achieves the desired results? If results are defined to be topological robustness, computational efficiency, quantitative accuracy, and predictability, all within a computational domain that faithfully represents complex three-dimensional foundry molds, then the answer unfortunately remains no. Significant interfacial flow algorithm developments have occurred over the last decade, however, that could bring this answer closer to maybe. These developments have been both evolutionary and revolutionary, will continue to transpire for the near future. Might they become useful numerical recipes for mold filling simulations? Quite possibly. Recent progress in algorithms for interface kinematics and dynamics, linear solution methods, computer science issues such as parallelization and object-oriented programming, high resolution Navier-Stokes (NS) solution methods, and unstructured mesh techniques, must all be pursued as possible paths toward higher fidelity mold filling simulations. A detailed exposition of these algorithmic developments is beyond the scope of this paper, hence the authors choose to focus here exclusively on algorithms for interface kinematics. These interface tracking algorithms are designed to model the movement of interfaces relative to a reference frame such as a fixed mesh. Current interface tracking algorithm choices are numerous, so is any one best suited for mold filling simulation? Although a clear winner is not (yet) apparent, pros and cons are given in the following brief, critical review. Highlighted are those outstanding interface tracking algorithm issues the authors feel can hamper the reliable modeling of today`s foundry mold filling processes.

  6. Regional Transportation Simulation Tool for Emergency Planning

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

    rtstep-diag TRACC RESEARCH Computational Fluid Dynamics Computational Structural Mechanics Transportation Systems Modeling Regional Transportation Simulation Tool for Emergency Evacuation Planning (Click to play movie) Large-scale evacuations from major cities during no-notice events - such as chemical or radiological attacks, hazardous material spills, or earthquakes - have an obvious impact on large regions rather than on just the directly affected area. The scope of impact includes the

  7. Building America House Simulation Protocols (Revised)

    SciTech Connect (OSTI)

    Hendron, R.; Engebrecht, C.

    2010-10-01

    The House Simulation Protocol document was developed to track and manage progress toward Building America's multi-year, average whole-building energy reduction research goals for new construction and existing homes, using a consistent analytical reference point. This report summarizes the guidelines for developing and reporting these analytical results in a consistent and meaningful manner for all home energy uses using standard operating conditions.

  8. Methodology for Validating Building Energy Analysis Simulations

    SciTech Connect (OSTI)

    Judkoff, R.; Wortman, D.; O'Doherty, B.; Burch, J.

    2008-04-01

    The objective of this report was to develop a validation methodology for building energy analysis simulations, collect high-quality, unambiguous empirical data for validation, and apply the validation methodology to the DOE-2.1, BLAST-2MRT, BLAST-3.0, DEROB-3, DEROB-4, and SUNCAT 2.4 computer programs. This report covers background information, literature survey, validation methodology, comparative studies, analytical verification, empirical validation, comparative evaluation of codes, and conclusions.

  9. Dynamics Simulation in a Wave Environment

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

    Coupled Dynamic Simulation in a Wave Environment (Navatek, AEGIR, and WECs) Marine and Hydrokinetics Instrumentation Workshop 9 July 2012 David Kring, Navatek Ltd. Presentation Overview * Introduction to Navatek * AEGIR brief: resistance, seakeeping, global and local loads a 3D, NURBS-based, high-order, Rankine boundary element method ... from same lab as at MIT as WAMIT and SWAN, with pFFT acceleration coupling with controls, structures, aerodynamics, power take-offs * Some WEC applications at

  10. Beam-beam simulations for separated beams

    SciTech Connect (OSTI)

    Furman, Miguel A.

    2000-04-10

    We present beam-beam simulation results from a strong-strong gaussian code for separated beams for the LHC and RHIC. The frequency spectrum produced by the beam-beam collisions is readily obtained and offers a good opportunity for experimental comparisons. Although our results for the emittance blowup are preliminary, we conclude that, for nominal parameter values, there is no significant difference between separated beams and center-on-center collisions.

  11. NREL: National Residential Efficiency Measures Database - Simulation

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

    Protocols Simulation Protocols One overarching objective in providing this publicly-available, centralized resource of residential building retrofit measures is to improve the technical consistency and accuracy of the results of software programs. To this end, NREL has also developed a set of recommendations regarding modeling inputs and assumptions derived from two decades of residential buildings research via the Building America Research Program. Section III of the Building America House

  12. Loading relativistic Maxwell distributions in particle simulations

    SciTech Connect (OSTI)

    Zenitani, Seiji

    2015-04-15

    Numerical algorithms to load relativistic Maxwell distributions in particle-in-cell (PIC) and Monte-Carlo simulations are presented. For stationary relativistic Maxwellian, the inverse transform method and the Sobol algorithm are reviewed. To boost particles to obtain relativistic shifted-Maxwellian, two rejection methods are proposed in a physically transparent manner. Their acceptance efficiencies are ?50% for generic cases and 100% for symmetric distributions. They can be combined with arbitrary base algorithms.

  13. Engineering report for simulated riser installation

    SciTech Connect (OSTI)

    Brevick, C.H., Westinghouse Hanford

    1996-05-09

    The simulated riser installation field tests demonstrated that new access ports (risers) can be installed safely, quickly, and economically in the concrete domes of existing underground single- shell waste storage tanks by utilizing proven rotary drilling equipment and vacuum excavation techniques. The new riser installation will seal against water intrusion, provide as table riser anchored to the tank dome, and be installed in accordance with ALARA principles. The information contained in the report will apply to actual riser installation activity in the future.

  14. MHK Reference Model: Relevance to Computer Simulation

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

    Diana Bull Sandia National Laboratories July 9 th , 2012 SAND Number: 2012-5508P MHK Reference Model: Relevance to Computer Simulation Reference Model Partners Oregon State University /NNMREC University of Washington St. Anthony Falls Laboratory-UMinn Florida Atlantic University / SNMREC Cardinal Engineering WEC Design Operational Waves Profile Design of WEC--Performance Structural Design of WEC PTO Design Survival Waves Structural Design of WEC--Survivability Brake Design Anchor and Mooring

  15. advanced simulation and computing | National Nuclear Security

    National Nuclear Security Administration (NNSA)

    Administration simulation and computing | National Nuclear Security Administration Facebook Twitter Youtube Flickr RSS People Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response Recapitalizing Our Infrastructure Countering Nuclear Terrorism About Our Programs Our History Who We Are Our Leadership Our Locations Budget Our Operations Library Bios Congressional Testimony Fact Sheets Newsletters Press Releases Photo Gallery Jobs Apply for Our Jobs

  16. Theory, Modeling and Simulation Annual Report 2000

    SciTech Connect (OSTI)

    Dixon, David A; Garrett, Bruce C; Straatsma, TP; Jones, Donald R; Studham, Scott; Harrison, Robert J; Nichols, Jeffrey A

    2001-11-01

    This annual report describes the 2000 research accomplishments for the Theory, Modeling, and Simulation (TM and S) directorate, one of the six research organizations in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). EMSL is a U.S. Department of Energy (DOE) national scientific user facility and is the centerpiece of the DOE commitment to providing world-class experimental, theoretical, and computational capabilities for solving the nation's environmental problems.

  17. Theory, Modeling and Simulation Annual Report 2000

    SciTech Connect (OSTI)

    Dixon, David A.; Garrett, Bruce C.; Straatsma, Tp; Jones, Donald R.; Studham, Ronald S.; Harrison, Robert J.; Nichols, Jeffrey A.

    2001-11-01

    This annual report describes the 2000 research accomplishments for the Theory, Modeling, and Simulation (TM&S) directorate, one of the six research organizations in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). EMSL is a U.S. Department of Energy (DOE) national scientific user facility and is the centerpiece of the DOE commitment to providing world-class experimental, theoretical, and computational capabilities for solving the nation's environmental problems.

  18. Status report on high fidelity reactor simulation.

    SciTech Connect (OSTI)

    Palmiotti, G.; Smith, M.; Rabiti, C.; Lewis, E.; Yang, W.; Leclere,M.; Siegel, A.; Fischer, P.; Kaushik, D.; Ragusa, J.; Lottes, J.; Smith, B.

    2006-12-11

    This report presents the effort under way at Argonne National Laboratory toward a comprehensive, integrated computational tool intended mainly for the high-fidelity simulation of sodium-cooled fast reactors. The main activities carried out involved neutronics, thermal hydraulics, coupling strategies, software architecture, and high-performance computing. A new neutronics code, UNIC, is being developed. The first phase involves the application of a spherical harmonics method to a general, unstructured three-dimensional mesh. The method also has been interfaced with a method of characteristics. The spherical harmonics equations were implemented in a stand-alone code that was then used to solve several benchmark problems. For thermal hydraulics, a computational fluid dynamics code called Nek5000, developed in the Mathematics and Computer Science Division for coupled hydrodynamics and heat transfer, has been applied to a single-pin, periodic cell in the wire-wrap geometry typical of advanced burner reactors. Numerical strategies for multiphysics coupling have been considered and higher-accuracy efficient methods proposed to finely simulate coupled neutronic/thermal-hydraulic reactor transients. Initial steps have been taken in order to couple UNIC and Nek5000, and simplified problems have been defined and solved for testing. Furthermore, we have begun developing a lightweight computational framework, based in part on carefully selected open source tools, to nonobtrusively and efficiently integrate the individual physics modules into a unified simulation tool.

  19. Mesh infrastructure for coupled multiprocess geophysical simulations

    SciTech Connect (OSTI)

    Garimella, Rao V.; Perkins, William A.; Buksas, Mike W.; Berndt, Markus; Lipnikov, Konstantin; Coon, Ethan; Moulton, John D.; Painter, Scott L.

    2014-01-01

    We have developed a sophisticated mesh infrastructure capability to support large scale multiphysics simulations such as subsurface flow and reactive contaminant transport at storage sites as well as the analysis of the effects of a warming climate on the terrestrial arctic. These simulations involve a wide range of coupled processes including overland flow, subsurface flow, freezing and thawing of ice rich soil, accumulation, redistribution and melting of snow, biogeochemical processes involving plant matter and finally, microtopography evolution due to melting and degradation of ice wedges below the surface. In addition to supporting the usual topological and geometric queries about the mesh, the mesh infrastructure adds capabilities such as identifying columnar structures in the mesh, enabling deforming of the mesh subject to constraints and enabling the simultaneous use of meshes of different dimensionality for subsurface and surface processes. The generic mesh interface is capable of using three different open source mesh frameworks (MSTK, MOAB and STKmesh) under the hood allowing the developers to directly compare them and choose one that is best suited for the application's needs. We demonstrate the results of some simulations using these capabilities as well as present a comparison of the performance of the different mesh frameworks.

  20. Software Framework for Advanced Power Plant Simulations

    SciTech Connect (OSTI)

    John Widmann; Sorin Munteanu; Aseem Jain; Pankaj Gupta; Mark Moales; Erik Ferguson; Lewis Collins; David Sloan; Woodrow Fiveland; Yi-dong Lang; Larry Biegler; Michael Locke; Simon Lingard; Jay Yun

    2010-08-01

    This report summarizes the work accomplished during the Phase II development effort of the Advanced Process Engineering Co-Simulator (APECS). The objective of the project is to develop the tools to efficiently combine high-fidelity computational fluid dynamics (CFD) models with process modeling software. During the course of the project, a robust integration controller was developed that can be used in any CAPE-OPEN compliant process modeling environment. The controller mediates the exchange of information between the process modeling software and the CFD software. Several approaches to reducing the time disparity between CFD simulations and process modeling have been investigated and implemented. These include enabling the CFD models to be run on a remote cluster and enabling multiple CFD models to be run simultaneously. Furthermore, computationally fast reduced-order models (ROMs) have been developed that can be 'trained' using the results from CFD simulations and then used directly within flowsheets. Unit operation models (both CFD and ROMs) can be uploaded to a model database and shared between multiple users.

  1. Mesh infrastructure for coupled multiprocess geophysical simulations

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

    Garimella, Rao V.; Perkins, William A.; Buksas, Mike W.; Berndt, Markus; Lipnikov, Konstantin; Coon, Ethan; Moulton, John D.; Painter, Scott L.

    2014-01-01

    We have developed a sophisticated mesh infrastructure capability to support large scale multiphysics simulations such as subsurface flow and reactive contaminant transport at storage sites as well as the analysis of the effects of a warming climate on the terrestrial arctic. These simulations involve a wide range of coupled processes including overland flow, subsurface flow, freezing and thawing of ice rich soil, accumulation, redistribution and melting of snow, biogeochemical processes involving plant matter and finally, microtopography evolution due to melting and degradation of ice wedges below the surface. In addition to supporting the usual topological and geometric queries about themoreĀ Ā» mesh, the mesh infrastructure adds capabilities such as identifying columnar structures in the mesh, enabling deforming of the mesh subject to constraints and enabling the simultaneous use of meshes of different dimensionality for subsurface and surface processes. The generic mesh interface is capable of using three different open source mesh frameworks (MSTK, MOAB and STKmesh) under the hood allowing the developers to directly compare them and choose one that is best suited for the application's needs. We demonstrate the results of some simulations using these capabilities as well as present a comparison of the performance of the different mesh frameworks.Ā«Ā less

  2. Xyce(Ā™) Parallel Electronic Simulator

    Energy Science and Technology Software Center (OSTI)

    2013-10-03

    The Xyce Parallel Electronic Simulator simulates electronic circuit behavior in DC, AC, HB, MPDE and transient mode using standard analog (DAE) and/or device (PDE) device models including several age and radiation aware devices. It supports a variety of computing platforms (both serial and parallel) computers. Lastly, it uses a variety of modern solution algorithms dynamic parallel load-balancing and iterative solvers.! ! Xyce is primarily used to simulate the voltage and current behavior of a circuitmoreĀ Ā» network (a network of electronic devices connected via a conductive network). As a tool, it is mainly used for the design and analysis of electronic circuits.! ! Kirchoff's conservation laws are enforced over a network using modified nodal analysis. This results in a set of differential algebraic equations (DAEs). The resulting nonlinear problem is solved iteratively using a fully coupled Newton method, which in turn results in a linear system that is solved by either a standard sparse-direct solver or iteratively using Trilinos linear solver packages, also developed at Sandia National Laboratories.Ā«Ā less

  3. Real Time Simulation of Power Grid Disruptions

    SciTech Connect (OSTI)

    Chinthavali, Supriya; Dimitrovski, Aleksandar D; Fernandez, Steven J; Groer, Christopher S; Nutaro, James J; Olama, Mohammed M; Omitaomu, Olufemi A; Shankar, Mallikarjun; Spafford, Kyle L; Vacaliuc, Bogdan

    2012-11-01

    DOE-OE and DOE-SC workshops (Reference 1-3) identified the key power grid problem that requires insight addressable by the next generation of exascale computing is coupling of real-time data streams (1-2 TB per hour) as the streams are ingested to dynamic models. These models would then identify predicted disruptions in time (2-4 seconds) to trigger the smart grid s self healing functions. This project attempted to establish the feasibility of this approach and defined the scientific issues, and demonstrated example solutions to important smart grid simulation problems. These objectives were accomplished by 1) using the existing frequency recorders on the national grid to establish a representative and scalable real-time data stream; 2) invoking ORNL signature identification algorithms; 3) modeling dynamically a representative region of the Eastern interconnect using an institutional cluster, measuring the scalability and computational benchmarks for a national capability; and 4) constructing a prototype simulation for the system s concept of smart grid deployment. The delivered ORNL enduring capability included: 1) data processing and simulation metrics to design a national capability justifying exascale applications; 2) Software and intellectual property built around the example solutions; 3) demonstrated dynamic models to design few second self-healing.

  4. Characterization and Simulation of Gunfire with Wavelets

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

    Smallwood, David O.

    1999-01-01

    Gunfire is used as an example to show how the wavelet transform can be used to characterize and simulate nonstationary random events when an ensemble of events is available. The structural response to nearby firing of a high-firing rate gun has been characterized in several ways as a nonstationary random process. The current paper will explore a method to describe the nonstationary random process using a wavelet transform. The gunfire record is broken up into a sequence of transient waveforms each representing the response to the firing of a single round. A wavelet transform is performed on each of thesemoreĀ Ā» records. The gunfire is simulated by generating realizations of records of a single-round firing by computing an inverse wavelet transform from Gaussian random coefficients with the same mean and standard deviation as those estimated from the previously analyzed gunfire record. The individual records are assembled into a realization of many rounds firing. A second-order correction of the probability density function is accomplished with a zero memory nonlinear function. The method is straightforward, easy to implement, and produces a simulated record much like the measured gunfire record.Ā«Ā less

  5. Memory Optimization for Phase-field Simulations

    SciTech Connect (OSTI)

    Derek Gaston; John Peterson; Andrew Slaughter; Cody Permann; David Andrs

    2014-08-01

    Phase-field simulations are computationally and memory intensive applications. Many of the phase-field simulations being conducted in support of NEAMS were not capable of running on “normal clusters” with 2-4GB of RAM per core, and instead required specialized “big-memory” clusters with 64GB per core. To address this issue, the MOOSE team developed a new Python-based utility called MemoryLogger, and applied it to locate, diagnose, and eradicate memory bottlenecks within the MOOSE framework. MemoryLogger allows for a better understanding of the memory usage of an application being run in parallel across a cluster. Memory usage information is captured for every individual process in a parallel job, and communicated to the head node of the cluster. Console text output from the application itself is automatically matched with this memory usage information to produce a detailed picture of memory usage over time, making it straightforward to identify the subroutines which contribute most to the application’s peak memory usage. The information produced by the MemoryLogger quickly and effectively narrows the search for memory optimizations to the most data-intensive parts of the simulation.

  6. DWPF Simulant CPC Studies For SB8

    SciTech Connect (OSTI)

    Newell, J. D.

    2013-09-25

    Prior to processing a Sludge Batch (SB) in the Defense Waste Processing Facility (DWPF), flowsheet studies using simulants are performed. Typically, the flowsheet studies are conducted based on projected composition(s). The results from the flowsheet testing are used to 1) guide decisions during sludge batch preparation, 2) serve as a preliminary evaluation of potential processing issues, and 3) provide a basis to support the Shielded Cells qualification runs performed at the Savannah River National Laboratory (SRNL). SB8 was initially projected to be a combination of the Tank 40 heel (Sludge Batch 7b), Tank 13, Tank 12, and the Tank 51 heel. In order to accelerate preparation of SB8, the decision was made to delay the oxalate-rich material from Tank 12 to a future sludge batch. SB8 simulant studies without Tank 12 were reported in a separate report.1 The data presented in this report will be useful when processing future sludge batches containing Tank 12. The wash endpoint target for SB8 was set at a significantly higher sodium concentration to allow acceptable glass compositions at the targeted waste loading. Four non-coupled tests were conducted using simulant representing Tank 40 at 110-146% of the Koopman Minimum Acid requirement. Hydrogen was generated during high acid stoichiometry (146% acid) SRAT testing up to 31% of the DWPF hydrogen limit. SME hydrogen generation reached 48% of of the DWPF limit for the high acid run. Two non-coupled tests were conducted using simulant representing Tank 51 at 110-146% of the Koopman Minimum Acid requirement. Hydrogen was generated during high acid stoichiometry SRAT testing up to 16% of the DWPF limit. SME hydrogen generation reached 49% of the DWPF limit for hydrogen in the SME for the high acid run. Simulant processing was successful using previously established antifoam addition strategy. Foaming during formic acid addition was not observed in any of the runs. Nitrite was destroyed in all runs and no N2O was detected during SME processing. Mercury behavior was consistent with that seen in previous SRAT runs. Mercury was stripped below the DWPF limit on 0.8 wt% for all runs. Rheology yield stress fell within or below the design basis of 1-5 Pa. The low acid Tank 40 run (106% acid stoichiometry) had the highest yield stress at 3.78 Pa.

  7. Epidemilogical Simulation System, Version 2.4

    Energy Science and Technology Software Center (OSTI)

    2004-01-30

    EpiSims uses a detailed simulation of disease spread to evaluate demographically and geographically targeted biological threat reduction strategies. Abstract: EpiSims simulates the spread of disease and analyzes the consequences of intervention strategies in a large urban area at the level of individuals. The simulation combines models of three dynamical systems: urban social networks, disease transmission, and within-host progression of a disease. Validated population mobility and activity generation technology provides the social network models, Disease modelsmoreĀ Ā» are based on fusion of expert opinion and available data. EpiSims provides a previously unavailable detailed representation of the course of an outbreak in urban area. A letter of August 16, 2002 from the Office of Homeland Security states: "Ability of EpiSims to provide comprehensive data on daily activity patterns of individuals makes it far superior to traditional SIR models Ā— clearly had an impact on pre-attack smallpox vaccination policy." EpiSims leverages a unique Los Alamos National Laboratory resource Ā— the population mobility and activity data developed by TRANSIMS (Transportation Analysis and SiMulation System) Ā— to create epidemiological analyses at an unprecedented level of detail. We create models of microscopic (individual-level) physical and biological processes from which, through simulation, emerge the macroscopic (urban regional level) quantities that are the inputs to alternative models. For example, the contact patterns of individuals in different demographic groups determine the overall mixing rates those groups. The characteristics of a person-to-person transmission together with their contact patterns determine the reproductive numbers Ā— how many people will be infected on average by each case. Mixing rates and reproductive numbers are the basic parameters of other epidemiological models. Because interventions Ā— and peopleĀ’s reactions to them Ā— are ultimately applied at the individual level, EpiSims is uniquely suited to evaluate their macroscopic consequences. For example, the debate over the logistics of targeted vaccination for smallpox, and thus the magnitude of the threat it poses, can best be resolved through an individual- based approach. EpiSims is the only available analytical tool using the individual-based approach that can scale to populations of a million or more without introducing ad-hoc assumptions about the nature of the social network. Impact: The first study commissioned for the EpiSims project was to analyze the effectiveness of targeted vaccination and isolation strategies in the aftermath of a covert release of smallpox at a crowded urban location. In particular we compared casualties and resources required for targeted strategies with those in the case of large-scale quarantine and/or mass vaccination campaigns. We produced this analysis in a sixty-day effort, while prototype software was still under development and delivered it to the Office of Homeland Security in June 2002. More recently, EpiSims provided casualty estimates and cost/benefit analyses for various proposed responses to an attack with pneumonic plague during the TOPOFF-2 exercise. Capabilities: EpiSims is designed to simulate human-human transmissible disease, but it is part of a suite of tools that naturally allow it to estimate individual exposures to air-borne or water-borne spread. Combined with data on animal density and mobility, EpiSims could simulate diseases spread by non-human vectors. EpiSims incorporates reactions of individuals, and is particularly powerful if those reactions are correlated with demographics. It provides a standard for modeling scenarios that cuts across agencies.Ā«Ā less

  8. Simulator procurement guidelines for fossil power plants: Final report

    SciTech Connect (OSTI)

    Lewis-Clapper, R.C.; Colby, F.J.; Gaddy, C.D.; Stone, H.P. II

    1994-12-01

    EPRI compact simulators are more effective, more flexible, and less expensive than conventional simulators. As a result, these simulators can benefit utilities in many ways, ranging from improving heat rate and decreasing O and M costs to reducing control system retrofit costs. Similarly, simulator applications range from operator training to engineering analyses and new product testing. These guidelines help utilities efficiently develop simulator specifications and procure these simulators. The guidelines cover the three phases of the procurement process: (1) pre-specification, (2) specification development, and (3) post-specification. For each phase, the guidelines include specific steps to take and use examples to point out how to avoid problems. Guideline appendices include a generic simulator specification. To help transfer the information in the guidelines to the industry, EPRI has also developed a simulator procurement workshop and a six-hour videotape series based on the workshop.

  9. New Algorithm Enables Faster Simulations of Ultrafast Processes

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

    Ultrafast Processes Opens the Door for Real-Time Simulations in Atomic-Level Materials ... Numerical simulations in real time provide the best way to study these processes, but such ...

  10. HEAVY-DUTY TRUCK EMISSIONS AND FUEL CONSUMPTION SIMULATING REAL...

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

    HEAVY-DUTY TRUCK EMISSIONS AND FUEL CONSUMPTION SIMULATING REAL-WORLD DRIVING IN LABORATORY CONDITIONS HEAVY-DUTY TRUCK EMISSIONS AND FUEL CONSUMPTION SIMULATING REAL-WORLD DRIVING ...

  11. Large-Scale Atomistic Simulations of Material Failure

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

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

    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.

  12. The Paul Trap Simulator Experiment (PTSX) | Princeton Plasma...

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

    The Paul Trap Simulator Experiment (PTSX) The Paul Trap Simulator Experiment (PTSX) at the U.S. Department of Energy's Princeton Plasma Physics Laboratory doesn't trap people named...

  13. Sandia Energy - Upper Rio Grande Simulation Model (URGSiM)

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

    Upper Rio Grande Simulation Model (URGSiM) Home Climate & Earth Systems WaterEnergy Nexus Decision Models for Integrating EnergyWater Systems Modeling Upper Rio Grande Simulation...

  14. Transient Simulation of a 2007 Prototype Heavy-Duty Engine |...

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

    Simulation of a 2007 Prototype Heavy-Duty Engine Transient Simulation of a 2007 Prototype Heavy-Duty Engine 2004 Diesel Engine Emissions Reduction (DEER) Conference PresentationL...

  15. Microworlds, Simulators, and Simulation: Framework for a Benchmark of Human Reliability Data Sources

    SciTech Connect (OSTI)

    Ronald Boring; Dana Kelly; Carol Smidts; Ali Mosleh; Brian Dyre

    2012-06-01

    In this paper, we propose a method to improve the data basis of human reliability analysis (HRA) by extending the data sources used to inform HRA methods. Currently, most HRA methods are based on limited empirical data, and efforts to enhance the empirical basis behind HRA methods have not yet yielded significant new data. Part of the reason behind this shortage of quality data is attributable to the data sources used. Data have been derived from unrelated industries, from infrequent risk-significant events, or from costly control room simulator studies. We propose a benchmark of four data sources: a simplified microworld simulator using unskilled student operators, a full-scope control room simulator using skilled student operators, a full-scope control room simulator using licensed commercial operators, and a human performance modeling and simulation system using virtual operators. The goal of this research is to compare findings across the data sources to determine to what extent data may be used and generalized from cost effective sources.

  16. New Algorithm Enables Faster Simulations of Ultrafast Processes

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

    Algorithm Enables Faster Simulations of Ultrafast Processes New Algorithm Enables Faster Simulations of Ultrafast Processes Opens the Door for Real-Time Simulations in Atomic-Level Materials Research February 20, 2015 Contact: Rachel Berkowitz, 510-486-7254, rberkowitz@lbl.gov femtosecondalgorithm copy Model of ion (Cl) collision with atomically thin semiconductor (MoSe2). Collision region is shown in blue and zoomed in; red points show initial positions of Cl. The simulation calculates the

  17. Tool - Vehicle System Simulation (Autonomie) | Argonne National Laboratory

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

    Tool - Vehicle System Simulation (Autonomie) Tool - Vehicle System Simulation (Autonomie) Autonomie s a most powerful and robust system simulation tool for vehicle energy consumption and performance analysis. Developed in collaboration with General Motors, Autonomie is a MATLABĀ©-based software environment and framework for automotive control-system design, simulation, and analysis. Its application covers energy consumption, performance analysis throughout the entire vehicle development process

  18. Conduit - Scientific Data Exchange Library for HPC Simulations

    Energy Science and Technology Software Center (OSTI)

    2014-10-22

    Conduit is a C++ software library that helps software developers with data representation and data exchange in scientific simulations

  19. A comparison of numerical simulations and analytical theory of...

    Office of Scientific and Technical Information (OSTI)

    English Subject: 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CAPTURE; CHIRALITY; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; COUPLING; CRYSTALS; DIPOLES;...

  20. MCNP simulations of material exposure experiments (u) (Technical Report) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect MCNP simulations of material exposure experiments (u) Citation Details In-Document Search Title: MCNP simulations of material exposure experiments (u) Simulations of proposed material exposure experiments were performed using MCNP6. The experiments will expose ampules containing different materials of interest with radiation to observe the chemical breakdown of the materials. Simulations were performed to map out dose in materials as a function of distance from the source,

  1. De Novo Ultrascale Atomistic Simulations On High-End Parallel

    Office of Scientific and Technical Information (OSTI)

    Supercomputers (Journal Article) | SciTech Connect De Novo Ultrascale Atomistic Simulations On High-End Parallel Supercomputers Citation Details In-Document Search Title: De Novo Ultrascale Atomistic Simulations On High-End Parallel Supercomputers We present a de novo hierarchical simulation framework for first-principles based predictive simulations of materials and their validation on high-end parallel supercomputers and geographically distributed clusters. In this framework, high-end

  2. A Fast Monte Carlo Simulation for the International Linear Collider

    Office of Scientific and Technical Information (OSTI)

    Detector (Technical Report) | SciTech Connect A Fast Monte Carlo Simulation for the International Linear Collider Detector Citation Details In-Document Search Title: A Fast Monte Carlo Simulation for the International Linear Collider Detector The following paper contains details concerning the motivation for, implementation and performance of a Java-based fast Monte Carlo simulation for a detector designed to be used in the International Linear Collider. This simulation, presently included

  3. Analyzing and Visualizing Cosmological Simulations with ParaView (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Journal Article: Analyzing and Visualizing Cosmological Simulations with ParaView Citation Details In-Document Search Title: Analyzing and Visualizing Cosmological Simulations with ParaView The advent of large cosmological sky surveys - ushering in the era of precision cosmology - has been accompanied by ever larger cosmological simulations. The analysis of these simulations, which currently encompass tens of billions of particles and up to a trillion particles in

  4. An Integrated Platform for Engine Performance Simulations and Optimization

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

    under Diesel Conditions | Department of Energy An Integrated Platform for Engine Performance Simulations and Optimization under Diesel Conditions An Integrated Platform for Engine Performance Simulations and Optimization under Diesel Conditions The direct injection stochastic reactor model is capable of accurate simulation of combustion under diesel conditions and can also be used to simulate and test different fuels. PDF icon p-17_pasternak.pdf More Documents & Publications Ricardo's

  5. SimFS: A Large Scale Parallel File System Simulator

    Energy Science and Technology Software Center (OSTI)

    2011-08-30

    The software provides both framework and tools to simulate a large-scale parallel file system such as Lustre.

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

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Northern Basin & Range Region (Pritchett, 2004) Exploration Activity...

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

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Central Nevada Seismic Zone Region (Pritchett, 2004) Exploration...

  8. Modeling-Computer Simulations At Geysers Area (Goff & Decker...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Geysers Area (Goff & Decker, 1983) Exploration Activity Details...

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

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Dixie Valley Geothermal Area (Wisian & Blackwell, 2004) Exploration...

  10. Modeling-Computer Simulations At Raft River Geothermal Area ...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Raft River Geothermal Area (1980) Exploration Activity Details...

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

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations (Lewicki & Oldenburg, 2004) Exploration Activity Details Location...

  12. Modeling-Computer Simulations At Desert Peak Area (Wisian & Blackwell...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Desert Peak Area (Wisian & Blackwell, 2004) Exploration Activity...

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

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations (Combs, Et Al., 1999) Exploration Activity Details Location Unspecified...

  14. Modeling-Computer Simulations At Yellowstone Region (Laney, 2005...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Yellowstone Region (Laney, 2005) Exploration Activity Details Location...

  15. Modeling-Computer Simulations At Raft River Geothermal Area ...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Raft River Geothermal Area (1979) Exploration Activity Details...

  16. Modeling-Computer Simulations At Raft River Geothermal Area ...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Raft River Geothermal Area (1977) Exploration Activity Details...

  17. Modeling-Computer Simulations (Ozkocak, 1985) | Open Energy Informatio...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations (Ozkocak, 1985) Exploration Activity Details Location Unspecified...

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

    Open Energy Info (EERE)

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

  19. Modeling-Computer Simulations At Stillwater Area (Wisian & Blackwell...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Stillwater Area (Wisian & Blackwell, 2004) Exploration Activity...

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

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Valles Caldera - Redondo Geothermal Area (Wilt & Haar, 1986)...

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

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Dixie Valley Geothermal Area (Kennedy & Soest, 2006) Exploration...

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

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations (Ranalli & Rybach, 2005) Exploration Activity Details Location...

  3. Modeling-Computer Simulations At Raft River Geothermal Area ...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Raft River Geothermal Area (1983) Exploration Activity Details...

  4. Hybrid Power System Simulation Model | Open Energy Information

    Open Energy Info (EERE)

    URI: cleanenergysolutions.orgcontenthybrid-power-system-simulation-model, Language: English Policies: Deployment Programs DeploymentPrograms: Technical Assistance This...

  5. Modeling and Simulation for Nuclear Reactors Hub | Department of Energy

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

    Modeling and Simulation for Nuclear Reactors Hub Modeling and Simulation for Nuclear Reactors Hub August 1, 2010 - 4:20pm Addthis Scientists and engineers are working to help the nuclear industry make reactors more efficient through computer modeling and simulation. Scientists and engineers are working to help the nuclear industry make reactors more efficient through computer modeling and simulation. The Department's Energy Innovation Hubs are helping to advance promising areas of energy science

  6. Revamped Simulation Tool to Power Up Wave Energy Development | Department

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

    of Energy Revamped Simulation Tool to Power Up Wave Energy Development Revamped Simulation Tool to Power Up Wave Energy Development May 21, 2015 - 2:40pm Addthis Revamped Simulation Tool to Power Up Wave Energy Development Alison LaBonte Marine and Hydrokinetic Technology Manager When engineers want to model new technologies, there's often nothing better than simulation tools. Designing technologies to harness energy from ocean waves is especially complex because engineers have to build them

  7. Simulation and optimization of ultra thin photovoltaics.

    SciTech Connect (OSTI)

    Cruz-Campa, Jose Luis

    2010-12-01

    Sandia National Laboratories (SNL) conducts pioneering research and development in Micro-Electro-Mechanical Systems (MEMS) and solar cell research. This dissertation project combines these two areas to create ultra-thin small-form-factor crystalline silicon (c-Si) solar cells. These miniature solar cells create a new class of photovoltaics with potentially novel applications and benefits such as dramatic reductions in cost, weight and material usage. At the beginning of the project, unusually low efficiencies were obtained in the research group. The intention of this research was thus to investigate the main causes of the low efficiencies through simulation, design, fabrication, and characterization. Commercial simulation tools were used to find the main causes of low efficiency. Once the causes were identified, the results were used to create improved designs and build new devices. In the simulations, parameters were varied to see the effect on the performance. The researched parameters were: resistance, wafer lifetime, contact separation, implant characteristics (size, dosage, energy, ratio between the species), contact size, substrate thickness, surface recombination, and light concentration. Out of these parameters, it was revealed that a high quality surface passivation was the most important for obtaining higher performing cells. Therefore, several approaches for enhancing the passivation were tried, characterized, and tested on cells. In addition, a methodology to contact and test the performance of all the cells presented in the dissertation under calibrated light was created. Also, next generation cells that could incorporate all the optimized layers including the passivation was designed, built, and tested. In conclusion, through this investigation, solar cells that incorporate optimized designs and passivation schemes for ultrathin solar cells were created for the first time. Through the application of the methods discussed in this document, the efficiency of the solar cells increased from below 1% to 15% in Microsystems Enabled Photovoltaic (MEPV) devices.

  8. A brightness exceeding simulated Langmuir limit

    SciTech Connect (OSTI)

    Nakasuji, Mamoru

    2013-08-15

    When an excitation of the first lens determines a beam is parallel beam, a brightness that is 100 times higher than Langmuir limit is measured experimentally, where Langmuir limits are estimated using a simulated axial cathode current density which is simulated based on a measured emission current. The measured brightness is comparable to Langmuir limit, when the lens excitation is such that an image position is slightly shorter than a lens position. Previously measured values of brightness for cathode apical radii of curvature 20, 60, 120, 240, and 480 ?m were 8.7, 5.3, 3.3, 2.4, and 3.9 times higher than their corresponding Langmuir limits, respectively, in this experiment, the lens excitation was such that the lens and the image positions were 180 mm and 400 mm, respectively. From these measured brightness for three different lens excitation conditions, it is concluded that the brightness depends on the first lens excitation. For the electron gun operated in a space charge limited condition, some of the electrons emitted from the cathode are returned to the cathode without having crossed a virtual cathode. Therefore, method that assumes a Langmuir limit defining method using a Maxwellian distribution of electron velocities may need to be revised. For the condition in which the values of the exceeding the Langmuir limit are measured, the simulated trajectories of electrons that are emitted from the cathode do not cross the optical axis at the crossover, thus the law of sines may not be valid for high brightness electron beam systems.

  9. Accelerating Subsurface Transport Simulation on Heterogeneous Clusters

    SciTech Connect (OSTI)

    Villa, Oreste; Gawande, Nitin A.; Tumeo, Antonino

    2013-09-23

    Reactive transport numerical models simulate chemical and microbiological reactions that occur along a flowpath. These models have to compute reactions for a large number of locations. They solve the set of ordinary differential equations (ODEs) that describes the reaction for each location through the Newton-Raphson technique. This technique involves computing a Jacobian matrix and a residual vector for each set of equation, and then solving iteratively the linearized system by performing Gaussian Elimination and LU decomposition until convergence. STOMP, a well known subsurface flow simulation tool, employs matrices with sizes in the order of 100x100 elements and, for numerical accuracy, LU factorization with full pivoting instead of the faster partial pivoting. Modern high performance computing systems are heterogeneous machines whose nodes integrate both CPUs and GPUs, exposing unprecedented amounts of parallelism. To exploit all their computational power, applications must use both the types of processing elements. For the case of subsurface flow simulation, this mainly requires implementing efficient batched LU-based solvers and identifying efficient solutions for enabling load balancing among the different processors of the system. In this paper we discuss two approaches that allows scaling STOMP's performance on heterogeneous clusters. We initially identify the challenges in implementing batched LU-based solvers for small matrices on GPUs, and propose an implementation that fulfills STOMP's requirements. We compare this implementation to other existing solutions. Then, we combine the batched GPU solver with an OpenMP-based CPU solver, and present an adaptive load balancer that dynamically distributes the linear systems to solve between the two components inside a node. We show how these approaches, integrated into the full application, provide speed ups from 6 to 7 times on large problems, executed on up to 16 nodes of a cluster with two AMD Opteron 6272 and a Tesla M2090 per node.

  10. Shock-to-Detonation Transition simulations

    SciTech Connect (OSTI)

    Menikoff, Ralph

    2015-07-14

    Shock-to-detonation transition (SDT) experiments with embedded velocity gauges provide data that can be used for both calibration and validation of high explosive (HE) burn models. Typically, a series of experiments is performed for each HE in which the initial shock pressure is varied. Here we describe a methodology for automating a series of SDT simulations and comparing numerical tracer particle velocities with the experimental gauge data. Illustrative examples are shown for PBX 9502 using the HE models implemented in the xRage ASC code at LANL.

  11. A queuing model for road traffic simulation

    SciTech Connect (OSTI)

    Guerrouahane, N.; Aissani, D.; Bouallouche-Medjkoune, L.; Farhi, N.

    2015-03-10

    We present in this article a stochastic queuing model for the raod traffic. The model is based on the M/G/c/c state dependent queuing model, and is inspired from the deterministic Godunov scheme for the road traffic simulation. We first propose a variant of M/G/c/c state dependent model that works with density-flow fundamental diagrams rather than density-speed relationships. We then extend this model in order to consider upstream traffic demand as well as downstream traffic supply. Finally, we show how to model a whole raod by concatenating raod sections as in the deterministic Godunov scheme.

  12. WEC-Sim (Wave Energy Converter - SIMulator)

    Energy Science and Technology Software Center (OSTI)

    2014-11-26

    WEC-Sim (Wave Energy Converter SIMulator) is a code developed by Sandia National Laboratories and the National Renewable Energy Laboratory to model wave energy converters (WECs) when they are subject to operational waves. The code is a time-domain modeling tool developed in MATLAB/Simulink using the multi-body dynamics solver SimMechanics. In WEC-Sim, WECs are modeled by connecting rigid bodies to one another with joint or constraint blocks from the WEC-Sim library. WEC-Sim is a publicly available, open-sourcemoreĀ Ā» code to model WECs.Ā«Ā less

  13. Statistical simulation ?of the magnetorotational dynamo

    SciTech Connect (OSTI)

    Squire, J.; Bhattacharjee, A.

    2014-08-01

    We analyze turbulence and dynamo induced by the magnetorotational instability (MRI) using quasi-linear statistical simulation methods. We find that homogenous turbulence is unstable to a large scale dynamo instability, which saturates to an inhomogenous equilibrium with a very strong dependence on the magnetic Prandtl number (Pm). Despite its enormously reduced nonlinearity, the quasi-linear model exhibits the same qualitative scaling of angular momentum transport with Pm as fully nonlinear turbulence. This demonstrates the relationship of recent convergence problems to the large scale dynamo and suggests possible methods for studying astrophysically relevant regimes at very low or high Pm.

  14. 2014 Building America House Simulation Protocols

    SciTech Connect (OSTI)

    Wilson, E.; Engebrecht-Metzger, C.; Horowitz, S.; Hendron, R.

    2014-03-01

    As BA has grown to include a large and diverse cross-section of the home building and retrofit industries, it has become more important to develop accurate, consistent analysis techniques to measure progress towards the program's goals. The House Simulation Protocol (HSP) document provides guidance to program partners and managers so they can compare energy savings for new construction and retrofit projects. The HSP provides the program with analysis methods that are proven to be effective and reliable in investigating the energy use of advanced energy systems and of entire houses.

  15. 2014 Building America House Simulation Protocols

    SciTech Connect (OSTI)

    Wilson, E.; Engebrecht, C. Metzger; Horowitz, S.; Hendron, R.

    2014-03-01

    As Building America has grown to include a large and diverse cross-section of the home building and retrofit industries, it has become more important to develop accurate, consistent analysis techniques to measure progress towards the program's goals. The House Simulation Protocol (HSP) document provides guidance to program partners and managers so they can compare energy savings for new construction and retrofit projects. The HSP provides the program with analysis methods that are proven to be effective and reliable in investigating the energy use of advanced energy systems and of entire houses.

  16. ADVANCED SIMULATION CAPABILITY FOR ENVIRONMENTAL MANAGEMENT

    Office of Scientific and Technical Information (OSTI)

    ADVANCED SIMULATION CAPABILITY FOR ENVIRONMENTAL MANAGEMENT (ASCEM): AN OVERVIEW OF INITIAL RESULTS Mark Williamson,* Juan Meza,ā€  David Moulton,ā€” Ian Gorton,Ā§ Mark Freshley,Ā§ Paul Dixon,ā€” Roger Seitz,Ā¶ Carl Steefel,ā€  Stefan Finsterle,ā€  Susan Hubbard,ā€  Ming Zhu,* Kurt Gerdes,* Russ Patterson,# and Yvette T. Collazo* *U.S. Department of Energy, Office of Environmental Management, Washington, DC, USA ā€ Lawrence Berkeley National Laboratory, Berkeley, CA, USA ā€”Los Alamos National

  17. 2014 International Workshop on Grid Simulator Testing

    Broader source: Energy.gov [DOE]

    The National Renewable Energy Laboratory (NREL) and Clemson University will host the second International Workshop on Grid Simulator Testing of Energy Systems and Wind Turbine Powertrains at the Duke Energy Electric Grid Research, Innovations and Development Center at 1253 Supply Street, North Charleston, South Carolina. The purpose of the workshop is to discuss the research and testing needs involved in grid compliance testing of utility-scale wind turbine generators. Information regarding the workshop can be found at: http://www.nrel.gov/esi/pdfs/201406_egrid_workshop_flyer.pdf.

  18. Geomechanical Simulation of Fluid-Driven Fractures

    SciTech Connect (OSTI)

    Makhnenko, R.; Nikolskiy, D.; Mogilevskaya, S.; Labuz, J.

    2012-11-30

    The project supported graduate students working on experimental and numerical modeling of rock fracture, with the following objectives: (a) perform laboratory testing of fluid-saturated rock; (b) develop predictive models for simulation of fracture; and (c) establish educational frameworks for geologic sequestration issues related to rock fracture. These objectives were achieved through (i) using a novel apparatus to produce faulting in a fluid-saturated rock; (ii) modeling fracture with a boundary element method; and (iii) developing curricula for training geoengineers in experimental mechanics, numerical modeling of fracture, and poroelasticity.

  19. BUSINESS PLAN ADVANCED SIMULATION AND COMPUTING

    National Nuclear Security Administration (NNSA)

    i BUSINESS PLAN ADVANCED SIMULATION AND COMPUTING 2015 NA-ASC-104R-15-Vol.1-Rev.0 ii Prepared by LLNL under Contract DE-AC52-07NA27344. This document was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor Lawrence Livermore National Security, LLC, nor any of their employees makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any

  20. WEC-Sim (Wave Energy Converter - SIMulator)

    SciTech Connect (OSTI)

    2014-11-26

    WEC-Sim (Wave Energy Converter SIMulator) is a code developed by Sandia National Laboratories and the National Renewable Energy Laboratory to model wave energy converters (WECs) when they are subject to operational waves. The code is a time-domain modeling tool developed in MATLAB/Simulink using the multi-body dynamics solver SimMechanics. In WEC-Sim, WECs are modeled by connecting rigid bodies to one another with joint or constraint blocks from the WEC-Sim library. WEC-Sim is a publicly available, open-source code to model WECs.