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1

High performance computing and numerical modelling  

E-Print Network (OSTI)

Numerical methods play an ever more important role in astrophysics. This is especially true in theoretical works, but of course, even in purely observational projects, data analysis without massive use of computational methods has become unthinkable. The key utility of computer simulations comes from their ability to solve complex systems of equations that are either intractable with analytic techniques or only amenable to highly approximative treatments. Simulations are best viewed as a powerful complement to analytic reasoning, and as the method of choice to model systems that feature enormous physical complexity such as star formation in evolving galaxies, the topic of this 43rd Saas Fee Advanced Course. The organizers asked me to lecture about high performance computing and numerical modelling in this winter school, and to specifically cover the basics of numerically treating gravity and hydrodynamics in the context of galaxy evolution. This is still a vast field, and I necessarily had to select a subset ...

,

2014-01-01T23:59:59.000Z

2

24 More Years of Numerical Weather Prediction: A Model Performance Model  

E-Print Network (OSTI)

24 More Years of Numerical Weather Prediction: A Model Performance Model Gerard Cats May 26, 2008 Abstract For two formulations of currently usual numerical weather prediction models the evolution in such a model is much 1 #12;24 More Years of Numerical Weather Prediction Gerard Cats higher than in a sis

Stoffelen, Ad

3

Numeric-modeling sensitivity analysis of the performance of wind turbine arrays  

SciTech Connect

An evaluation of the numerical model created by Lissaman for predicting the performance of wind turbine arrays has been made. Model predictions of the wake parameters have been compared with both full-scale and wind tunnel measurements. Only limited, full-scale data were available, while wind tunnel studies showed difficulties in representing real meteorological conditions. Nevertheless, several modifications and additions have been made to the model using both theoretical and empirical techniques and the new model shows good correlation with experiment. The larger wake growth rate and shorter near wake length predicted by the new model lead to reduced interference effects on downstream turbines and hence greater array efficiencies. The array model has also been re-examined and now incorporates the ability to show the effects of real meteorological conditions such as variations in wind speed and unsteady winds. The resulting computer code has been run to show the sensitivity of array performance to meteorological, machine, and array parameters. Ambient turbulence and windwise spacing are shown to dominate, while hub height ratio is seen to be relatively unimportant. Finally, a detailed analysis of the Goodnoe Hills wind farm in Washington has been made to show how power output can be expected to vary with ambient turbulence, wind speed, and wind direction.

Lissaman, P.B.S.; Gyatt, G.W.; Zalay, A.D.

1982-06-01T23:59:59.000Z

4

The effect of simplifying the building description on the numerical modeling of its thermal performance  

SciTech Connect

A thermal building simulation program is a numerical model that calculates the response of the building envelopes to weather and human activity, simulates dynamic heating and cooling loads, and heating and cooling distribution systems, and models building equipment operation. The scope of the research is to supply the users of such programs with information about the dangers and benefits of simplifying the input to their models. The Introduction describes the advantages of modeling the heat transfer mechanisms in a building. The programs that perform this type of modeling have, however, limitations. The user is therefore often put in the situation of simplifying the floor plans of the building under study, but not being able to check the effects that this approximation introduces in the results of the simulation. Chapter 1 is a description of methods. It also introduces the floor plans for the office building under study and the ``reasonable`` floor plans simplifications. Chapter 2 presents DOE-2, the thermal building simulation program used in the sensitivity study. The evaluation of the accuracy of the DOE-2 program itself is also presented. Chapter 3 contains the sensitivity study. The complicated nature of the process of interpreting the temperature profile inside a space leads to the necessity of defining different building modes. The study compares the results from the model of the detailed building description with the results from the models of the same building having simplified floor plans. The conclusion is reached that a study of the effects of simplifying the floor plans of a building is important mainly for defining the cases in which this approximation is acceptable. Different results are obtained for different air conditioning/load regimes of the building. 9 refs., 24 figs.

Stetiu, C.

1993-07-01T23:59:59.000Z

5

Improving the Performance of Mass-Consistent Numerical Models Using Optimization Techniques  

Science Journals Connector (OSTI)

This paper describes a technique of using a mass-consistent model to derive wind speeds over a microscale region (about 4 km2) of complex terrain. A serious limitation of these numerical models is that the calculated wind field is highly ...

J. C. Barnard; H. L. Wegley; T. R. Hiester

1987-06-01T23:59:59.000Z

6

Short term performance comparisons between a solar thermosyphon water heater and two numerical models  

SciTech Connect

An experimental study of a solar thermosyphon domestic water heater was conducted in the indoor solar simulator facility at Colorado State University (Bickford, 1994). The system consisted of a closed-loop collector circuit filled with propylene glycol and water solution and a horizontal storage tank with an annular tank-in-tank heat exchanger. Short-term irradiated tests with and without timed draws were performed to assess overall performance and monitor collector flow rate, storage tank stratification, and heat exchanger temperature distribution. The measured performance was compared with the ``standard`` thermosyphon model in TRNSYS 13.1 (transient system simulation program). A revised TRNSYS model was developed by Graham Morrison at the University of New South Wales, Australia. The revised model specifically addressed the horizontal tank, closed-loop configuration. The standard TRNSYS version predicted solar gain within 17% of the measured values and differed dramatically from experimental collector temperatures, closed-loop flow rate, and tank stratification. This is not surprising since this model does not include the tank and tank heat exchanger. The revised TRNSYS model agreed more closely with experimental results. It predicted closed-loop flow at 8% lower than observed flow and collector temperature rise that was higher than the observed flow by approximately the same amount, resulting in extremely accurate prediction of collector output energy. Losses from the storage tank and piping were significantly underpredicted in both models, however.

Bickford, C.; Hittle, D.C. [Colorado State Univ., Fort Collins, CO (United States). Solar Energy Applications Lab.

1995-11-01T23:59:59.000Z

7

Numerical Modeling of the Distributed Electrochemistry and Performance of Solid Oxide Fuel Cells  

SciTech Connect

A cell-level distributed electrochemistry (DEC) modeling tool has been developed to enable prediction of solid oxide fuel cell performance by considering the coupled and spatially varying multi-physics that occur within the tri-layer. The approach calculates the distributed electrochemistry within the electrodes, which includes the charge transfer and electric potential fields, ion transport throughout the tri-layer, and gas distributions within the composite and porous electrodes. The thickness of the electrochemically active regions within the electrodes is calculated along with the distributions of charge transfer. The DEC modeling tool can examine the overall SOFC performance based on electrode microstructural parameters, such as particle size, pore size, porosity factor, electrolyte and electrode phase volume fractions, and triple-phase-boundary length. Recent developments in electrode fabrication methods have lead to increased interest in using graded and nano-structured electrodes to improve the electrochemical performance of SOFCs. This paper demonstrates how the DEC modeling tool can be used to help design novel electrode microstructures by optimizing a graded anode for high electrochemical performance.

Recknagle, Kurtis P.; Ryan, Emily M.; Khaleel, Mohammad A.

2011-12-01T23:59:59.000Z

8

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

Science Journals Connector (OSTI)

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

Xueli Luo; Christian Day; Horst Haas; Stylianos Varoutis

2011-01-01T23:59:59.000Z

9

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

SciTech Connect

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

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

2011-07-15T23:59:59.000Z

10

CDA6530: Performance Models of Computers and Networks (Fall 2013) Project 2: Using Matlab Simulink to derive numerical solution for differential equations  

E-Print Network (OSTI)

CDA6530: Performance Models of Computers and Networks (Fall 2013) Project 2: Using Matlab Simulink matlab simulink from the example of the simple worm propagation modeling in class. Now you are asked to derive the numerical solutions for more complicated differential equations. If you cannot access Matlab

Zou, Cliff C.

11

Numerical Modeling | Open Energy Information  

Open Energy Info (EERE)

Numerical Modeling Numerical Modeling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Numerical Modeling Details Activities (8) Areas (2) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Data and Modeling Techniques Exploration Sub Group: Modeling Techniques Parent Exploration Technique: Modeling Techniques Information Provided by Technique Lithology: Stratigraphic/Structural: Stress fields and magnitudes Hydrological: Visualization and prediction of the flow patterns and characteristics of geothermal fluids Thermal: Thermal conduction and convection patterns in the subsurface Dictionary.png Numerical Modeling: A computer model that is designed to simulate and reproduce the mechanisms of a particular system. Other definitions:Wikipedia Reegle

12

Numerical Modeling of HCCI Combustion  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Numerical Modeling of HCCI Combustion Salvador M. Aceves, Daniel L. Flowers, J. Ray Smith, Joel Martinez-Frias, Francisco Espinosa-Loza, Tim Ross, Bruce Buchholz, Nick...

13

Numerical Modelling of Interaction between  

E-Print Network (OSTI)

plasma in arc furnace used in toxic waste destruction Plasma etching semiconductor High intensity arc lamp Electrode temperature after 1ms of arcing with power density of 3x109 W.m-2 Electrode temperatureNumerical Modelling of Interaction between the Electric Arc and Electrodes Principal researcher: W

Sóbester, András

14

numerical modeling | OpenEI Community  

Open Energy Info (EERE)

07 07 Varnish cache server Home Groups Community Central Green Button Applications Developer Utility Rate FRED: FRee Energy Database More Public Groups Private Groups Features Groups Blog posts Content Stream Documents Discussions Polls Q & A Events Notices My stuff Energy blogs 429 Throttled (bot load) Error 429 Throttled (bot load) Throttled (bot load) Guru Meditation: XID: 2142233807 Varnish cache server numerical modeling Home Ocop's picture Submitted by Ocop(5) Member 18 April, 2013 - 13:41 MHK LCOE Reporting Guidance Draft Cost Current DOE LCOE numerical modeling Performance Tidal Wave To normalize competing claims of LCOE, DOE has developed-for its own use-a standardized cost and performance data reporting process to facilitate uniform calculation of LCOE from MHK device developers. This

15

Numerical  

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

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

16

Numerical Wave Modeling in Conditions with Strong Currents: Dissipation, Refraction, and Relative Wind  

Science Journals Connector (OSTI)

Currents effects on waves have led to many developments in numerical wave modeling over the past two decades, from numerical choices to parameterizations. The performance of numerical models in conditions with strong currents is reviewed here, and ...

Fabrice Ardhuin; Aron Roland; Franck Dumas; Anne-Claire Bennis; Alexei Sentchev; Philippe Forget; Judith Wolf; Françoise Girard; Pedro Osuna; Michel Benoit

2012-12-01T23:59:59.000Z

17

CDA6530: Performance Models of Computers and Networks (Fall 2012) Project 2: Using Matlab Simulink to derive numerical solution for differential equations  

E-Print Network (OSTI)

CDA6530: Performance Models of Computers and Networks (Fall 2012) Project 2: Using Matlab SimulinkCourse) You have learned matlab simulink from the example of the simple worm propagation modeling in class. If you cannot access Matlab Simulink, you can use an equivalent free software 'Xcos' (similar to Simulink

Zou, Cliff C.

18

CDA6530: Performance Models of Computers and Networks (Fall 2011) Project 2: Using Matlab Simulink to derive numerical solution for differential equations  

E-Print Network (OSTI)

CDA6530: Performance Models of Computers and Networks (Fall 2011) Project 2: Using Matlab Simulink learned matlab simulink from the example of the simple worm propagation modeling in class. Now you submit this project assignment via webcourse. You should attach a Winzip file containing a document (such

Zou, Cliff C.

19

CDA6530: Performance Models of Computers and Networks (Fall 2010) Project 2: Using Matlab Simulink to derive numerical solution for differential equations  

E-Print Network (OSTI)

CDA6530: Performance Models of Computers and Networks (Fall 2010) Project 2: Using Matlab Simulink submission deadline: 11/02 midnight) You have learned matlab simulink from the example of the simple worm differential equations. Submission: please submit this project assignment via webcourse. You should attach

Zou, Cliff C.

20

IR DIAL performance modeling  

SciTech Connect

We are developing a DIAL performance model for CALIOPE at LLNL. The intent of the model is to provide quick and interactive parameter sensitivity calculations with immediate graphical output. A brief overview of the features of the performance model is given, along with an example of performance calculations for a non-CALIOPE application.

Sharlemann, E.T.

1994-07-01T23:59:59.000Z

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


21

423A HIGH-PERFORMANCE COMPUTING/NUMERICAL The International Journal of High Performance Computing Applications,  

E-Print Network (OSTI)

423A HIGH-PERFORMANCE COMPUTING/NUMERICAL The International Journal of High Performance Computing and barriers in the development of high-performance computing (HPC) algorithms and software. The activity has computing, numerical analy- sis, roadmap, applications and algorithms, software 1 The High-performance

Higham, Nicholas J.

22

Numerical Modeling of Failure in Magnesium Alloys under Axial Compression and Bending for Crashworthiness Applications.  

E-Print Network (OSTI)

??Numerical modeling of failure was performed for magnesium alloys with circular and square cross-sections under axial compression. The failure criterion was employed using material model… (more)

Ali, Usman

2012-01-01T23:59:59.000Z

23

MPI-StarT: delivering network performance to numerical applications  

Science Journals Connector (OSTI)

We describe an MPI implementation for a cluster of SMPs interconnected by a high-performance interconnect. This work is a collaboration between a numerical applications programmer and a cluster interconnect architect. The collaboration started with the ... Keywords: MITMatlab, MPI, MPICH, SMP, StarT-X, clustering, performance

Parry Husbands; James C. Hoe

1998-11-01T23:59:59.000Z

24

Definition: Numerical Modeling | Open Energy Information  

Open Energy Info (EERE)

Definition Definition Edit with form History Facebook icon Twitter icon » Definition: Numerical Modeling Jump to: navigation, search Dictionary.png Numerical Modeling A computer model that is designed to simulate and reproduce the mechanisms of a particular system.[1] View on Wikipedia Wikipedia Definition A computer simulation, a computer model, or a computational model is a computer program, run on a single computer, or a network of computers, that attempts to simulate an abstract model of a particular system. Computer simulations have become a useful part of mathematical modeling of many natural systems in physics, astrophysics, chemistry and biology, human systems in economics, psychology, social science, and engineering. Simulation of a system is represented as the running of the system's model.

25

Comparing Aerodynamic Models for Numerical Simulation of  

E-Print Network (OSTI)

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

Peraire, Jaime

26

Numerical Modeling of Acoustic Timescale Detonation Initiation Using the Adaptive  

E-Print Network (OSTI)

Numerical Modeling of Acoustic Timescale Detonation Initiation Using the Adaptive Wavelet 2008 #12;This thesis entitled: Numerical Modeling of Acoustic Timescale Detonation Initiation Using. (Ph.D.) Numerical Modeling of Acoustic Timescale Detonation Initiation Using the Adaptive Wavelet

Vasilyev, Oleg V.

27

Numerical Modeling of Acoustic Timescale Detonation J.D. Regele  

E-Print Network (OSTI)

Numerical Modeling of Acoustic Timescale Detonation Initiation J.D. Regele , D.R. Kassoy and O to perform one and two-dimensional simulations of acoustic timescale detonation initiation using thermal overdriven detonation wave that decays to a steady-state CJ wave. A 1-D parametric study of acoustic

Vasilyev, Oleg V.

28

Numerical Models of Extragalactic Radio Sources  

Science Journals Connector (OSTI)

...unpublished data. THOMPSON, A...unpublished data. Numerical models...observatories provided an infrastructure that resulted in high-quality data for both the expert...on an Eulerian grid in time and space...magnetic field is a hybrid of the constrained...

JACK O. BURNS; MICHAEL L. NORMAN; DAVID A. CLARKE

1991-08-02T23:59:59.000Z

29

Numerical Modeling of PCCI Combustion | Department of Energy  

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

Modeling of HCCI and PCCI Combustion Processes Numerical Modeling of HCCI Combustion Bridging the Gap between Fundamental Physics and Chemistry and Applied Models for HCCI Engines...

30

NUMERICAL MODELING OF CATHODE CONTACT MATERIAL DENSIFICATION  

SciTech Connect

Numerical modeling was used to simulate the constrained sintering process of the cathode contact layer during assembly of solid oxide fuel cells (SOFCs). A finite element model based on the continuum theory for sintering of porous bodies was developed and used to investigate candidate low-temperature cathode contact materials. Constitutive parameters for various contact materials under investigation were estimated from dilatometry screening tests, and the influence of processing time, processing temperature, initial grain size, and applied compressive stress on the free sintering response was predicted for selected candidate materials. The densification behavior and generated stresses within a 5-cell planar SOFC stack during sintering, high temperature operation, and room temperature shutdown were predicted. Insufficient constrained densification was observed in the stack at the proposed heat treatment, but beneficial effects of reduced grain size, compressive stack preload, and reduced thermal expansion coefficient on the contact layer densification and stresses were observed.

Koeppel, Brian J.; Liu, Wenning N.; Stephens, Elizabeth V.; Khaleel, Mohammad A.

2011-11-01T23:59:59.000Z

31

Forecasting wave height probabilities with numerical weather prediction models  

E-Print Network (OSTI)

Forecasting wave height probabilities with numerical weather prediction models Mark S. Roulstona; Numerical weather prediction 1. Introduction Wave forecasting is now an integral part of operational weather methods for generating such forecasts from numerical model output from the European Centre for Medium

Stevenson, Paul

32

A high-resolution, cloud-assimilating numerical weather prediction model for solar irradiance forecasting  

E-Print Network (OSTI)

Multiscale Numerical Weather Prediction Model.   Progress assimilating numerical weather prediction model for solar customizable  numerical weather prediction model that is 

Mathiesen, Patrick; Collier, Craig; Kleissl, Jan

2013-01-01T23:59:59.000Z

33

Numerical Modelling of Geothermal Systems a Short Introduction | Open  

Open Energy Info (EERE)

Numerical Modelling of Geothermal Systems a Short Introduction Numerical Modelling of Geothermal Systems a Short Introduction Jump to: navigation, search OpenEI Reference LibraryAdd to library General: Numerical Modelling of Geothermal Systems a Short Introduction Authors Mauro Cacace, Björn Onno Kaiser and Yvonne Cherubini Published Helmholtz Association, The date "N/A" was not understood.The date "N/A" was not understood. DOI Not Provided Check for DOI availability: http://crossref.org Online Internet link for Numerical Modelling of Geothermal Systems a Short Introduction Citation Mauro Cacace,Björn Onno Kaiser,Yvonne Cherubini. N/A. Numerical Modelling of Geothermal Systems a Short Introduction. N/A. Helmholtz Association. N/Ap. Retrieved from "http://en.openei.org/w/index.php?title=Numerical_Modelling_of_Geothermal_Systems_a_Short_Introduction&oldid=688986"

34

Data Assimilation for Idealised Mathematical Models of Numerical Weather Prediction  

E-Print Network (OSTI)

Data Assimilation for Idealised Mathematical Models of Numerical Weather Prediction Supervisors). Background: Numerical Weather Prediction (NWP) has seen significant gains in accuracy in recent years due is directed at achieving real-world impact in numerical weather prediction by addressing fundamental issues

Wirosoetisno, Djoko

35

Numerical Modeling At Dixie Valley Geothermal Area (Iovenitti...  

Open Energy Info (EERE)

Iovenitti, Et Al., 2013) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Numerical Modeling At Dixie Valley Geothermal Area (Iovenitti, Et Al.,...

36

Numerical models of phosphate esters in the Chattahoochee River  

E-Print Network (OSTI)

A numerical model was constructed to assess the magnitude of organophosphoric acid triester sinks in the Chattahoochee River and to identify concentration patterns downstream of point source discharges. The model was built ...

Haffey, Samuel Fraad, 1973-

2004-01-01T23:59:59.000Z

37

Electrowetting-based microfluidics: mathematical modeling and numerical simulation  

Science Journals Connector (OSTI)

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

Michael Franklin / Ali Nadim

2013-01-01T23:59:59.000Z

38

Numerical modeling of dish-Stirling reflux solar receivers  

SciTech Connect

Using reflux solar receivers to collect solar energy for dish-Stirling electric power generation systems is currently being investigated by several organizations, including Sandia National Laboratories, Albuquerque, New Mexico. In support of this program, Sandia has developed two numerical models describing the energy transfer within and thermal performance of pool-boiler and heat-pipe receivers. Both models are applicable to axisymmetric geometries and they both consider the radiative and convective energy transfer within the receiver cavity, the conductive and convective energy transfer within the receiver cavity, the conductive and convective energy transfer from the receiver housing, and the energy transfer to the receiver working fluid. In these models, the radiative transfer within the receiver is analyzed using a two-band (solar and infrared) net-radiation formulation for enclosure radiation. Empirical convective correlations describe the convective heat transfer from the cavity to the surroundings. The primary difference between the models is the level of detail in modeling the heat conduction through the receiver walls. The more detailed model uses a two-dimensional finite control volume method, whereas the simpler model uses a one-dimensional thermal resistance approach. 20 refs., 7 figs., 2 tabs.

Hogan, R.E.

1990-01-01T23:59:59.000Z

39

Numerical Modeling At Coso Geothermal Area (1995) | Open Energy Information  

Open Energy Info (EERE)

Numerical Modeling At Coso Geothermal Area (1995) Numerical Modeling At Coso Geothermal Area (1995) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Numerical Modeling At Coso Geothermal Area (1995) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Numerical Modeling Activity Date 1995 Usefulness useful DOE-funding Unknown Exploration Basis Locate an active fault zone by analyzing seismic guided waves from microearthquake data Notes An active fault zone was located in the Coso geothermal field, California, by identifying and analyzing a fault-zone trapped Rayleigh-type guided wave from microearthquake data. The wavelet transform is employed to characterize guided-wave's velocity-frequency dispersion, and numerical methods are used to simulate the guided-wave propagation. The modeling

40

Numerical Modeling Of Basin And Range Geothermal Systems | Open Energy  

Open Energy Info (EERE)

Numerical Modeling Of Basin And Range Geothermal Systems Numerical Modeling Of Basin And Range Geothermal Systems Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Numerical Modeling Of Basin And Range Geothermal Systems Details Activities (3) Areas (3) Regions (0) Abstract: Basic qualitative relationships for extensional geothermal systems that include structure, heat input, and permeability distribution have been established using numerical models. Extensional geothermal systems, as described in this paper, rely on deep circulation of groundwater rather than on cooling igneous bodies for heat, and rely on extensional fracture systems to provide permeable upflow paths. A series of steady-state, two-dimensional simulation models is used to evaluate the effect of permeability and structural variations on an idealized, generic

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


41

Multi-scale problems, high performance computing and hybrid numerical methods  

E-Print Network (OSTI)

Multi-scale problems, high performance computing and hybrid numerical methods G. Balarac, G of High Performance Computing G. Balarac LEGI, CNRS and Universit´e de Grenoble, BP 53, 38041 Grenoble

Cottet, Georges-Henri

42

Multi-scale problems, high performance computing and hybrid numerical methods  

E-Print Network (OSTI)

Multi-scale problems, high performance computing and hybrid numerical methods G. Balarac, G of High Performance Computing (HPC) is not anymore restricted to academia and scientific grand challenges

Paris-Sud XI, Université de

43

Accelerating Energy Savings Performance Contracting Through Model...  

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

Accelerating Energy Savings Performance Contracting Through Model Statewide Programs Accelerating Energy Savings Performance Contracting Through Model Statewide Programs Provides...

44

Numerical Modeling At Raft River Geothermal Area (1983) | Open Energy  

Open Energy Info (EERE)

Raft River Geothermal Area (1983) Raft River Geothermal Area (1983) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Numerical Modeling At Raft River Geothermal Area (1983) Exploration Activity Details Location Raft River Geothermal Area Exploration Technique Numerical Modeling Activity Date 1983 Usefulness not indicated DOE-funding Unknown Notes The numerical modeling of the resistivity data is marginal for changes as small as those observed but the results suggest that changes of a few percent could be expected from a fracture zone extending from depth to within 100 m of the surface. References Sill, W. R. (1 September 1983) Resistivity measurements before and after injection Test 5 at Raft River KGRA, Idaho. Final report Retrieved from "http://en.openei.org/w/index.php?title=Numerical_Modeling_At_Raft_River_Geothermal_Area_(1983)&oldid=47387

45

Numerical Modeling At Coso Geothermal Area (2000) | Open Energy Information  

Open Energy Info (EERE)

Numerical Modeling At Coso Geothermal Area (2000) Numerical Modeling At Coso Geothermal Area (2000) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Numerical Modeling Activity Date 2000 Usefulness not indicated DOE-funding Unknown Exploration Basis Determine areas with fault patterns for geothermal development using Poisson's ratio and porosity Notes High-resolution, three-dimensional, compressional and shear wave velocity models, derived from microearthquake travel times, are used to map the distribution of Poisson's ratio and porosity at Coso Geothermal Area. Spatial resolution of the three-dimensional Poisson's ratio and porosity distributions is estimated to be 0.5 km horizontally and 0.8 km vertically. Model uncertainties, + or -1% in the interior and + or -2.3% around the

46

Numerical modelling of MILD combustion for coal  

Science Journals Connector (OSTI)

Emissions of nitrogen oxides from coal combustion are a major environmental problem because they have been shown to contribute to the formation of acid rain and photochemical smog. Moderate and Intensive Low oxygen Dilution (MILD) combustion is a promising technology for decreasing pollutant emissions and improving combustion efficiency. A combination of air preheating and fuel dilution with combustion products of low oxygen concentration are the main features of this technique. In the MILD combustion mode, preheated air and fuel are gradually mixed with large amounts of recirculated exhaust gas. The objective of the present work is to investigate the capability of present fuel NO mechanisms for pulverised coal combustion to predict the observed nitrogen oxide levels in MILD combustion mode. For this purpose, knowledge of the fate of coal nitrogen during the combustion process is vital. The interaction between turbulence and chemistry is modelled by an advanced Eddy Dissipation Concept (EDC). The NOx model is used to predict NO profiles that are compared to measurements obtained from semi-industrial scale experiments.

Ju Pyo Kim; U. Schnell; G. Scheffknecht; A.C. Benim

2007-01-01T23:59:59.000Z

47

Thermal contact algorithms in SIERRA mechanics : mathematical background, numerical verification, and evaluation of performance.  

SciTech Connect

We examine algorithms for the finite element approximation of thermal contact models. We focus on the implementation of thermal contact algorithms in SIERRA Mechanics. Following the mathematical formulation of models for tied contact and resistance contact, we present three numerical algorithms: (1) the multi-point constraint (MPC) algorithm, (2) a resistance algorithm, and (3) a new generalized algorithm. We compare and contrast both the correctness and performance of the algorithms in three test problems. We tabulate the convergence rates of global norms of the temperature solution on sequentially refined meshes. We present the results of a parameter study of the effect of contact search tolerances. We outline best practices in using the software for predictive simulations, and suggest future improvements to the implementation.

Copps, Kevin D.; Carnes, Brian R.

2008-04-01T23:59:59.000Z

48

Multidimensional numerical modeling of heat exchangers. [LMFBR  

SciTech Connect

A comprehensive, multidimensional, thermal-hydraulic model is developed for the analysis of shell-and-tube heat exchangers for liquid-metal services. For the shellside fluid, the conservation equations of mass, momentum, and energy for continuum fluids are modified using the concept of porosity, surface permeability and distributed resistance to account for the blockage effects due to the presence of heat-transfer tubes, flow baffles/shrouds, the support plates, etc. On the tubeside, the heat-transfer tubes are connected in parallel between the inlet and outlet plenums, and tubeside flow distribution is calculated based on the plenum-to-plenum pressure difference being equal for all tubes. It is assumed that the fluid remains single-phase on the shell side and may undergo phase-change on the tube side, thereby simulating the conditions of Liquid Metal Fast Breeder Reactor (LMFBR) intermediate heat exchangers (IHX) and steam generators (SG).

Sha, W.T.; Yang, C.I.; Kao, T.T.; Cho, S.M.

1982-01-01T23:59:59.000Z

49

Analytical-Numerical Modeling Of Komatiite Lava Emplacement And Thermal  

Open Energy Info (EERE)

Analytical-Numerical Modeling Of Komatiite Lava Emplacement And Thermal Analytical-Numerical Modeling Of Komatiite Lava Emplacement And Thermal Erosion At Perseverance, Western Australia Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Analytical-Numerical Modeling Of Komatiite Lava Emplacement And Thermal Erosion At Perseverance, Western Australia Details Activities (0) Areas (0) Regions (0) Abstract: We have applied a thermal-fluid dynamic-geochemical model to investigate the emplacement and erosional potential of Archean komatiite flows at Perseverance, Western Australia. Perseverance has been proposed as a site of large-scale thermal erosion by large-volume komatiite eruption(s), resulting in a 100-150-m-deep lava channel containing one of the world's largest komatiite-hosted Fe-Ni-Cu-(PGE) sulfide deposits. Using

50

Numerical Modeling of Brain Dynamics in Traumatic Situations -Impulsive Translations  

E-Print Network (OSTI)

.S.A. Abstract We numerically model the brain dy- namics during and after impulsive head translations using brain injuries appear among boxers and shaken babies despite minimal rotations of their heads. Modeling head translations also helps understand the brain dynamics during head rotations about an arbitrary

Burtscher, Martin

51

Numerical models of black body dominated GRBs: II. Emission properties  

E-Print Network (OSTI)

We extend an existing theoretical model to explain the class of Black-Body Dominated (BBD) gamma-ray bursts (GRBs), long lasting events characterized by the presence of a significant thermal component trailing the GRB prompt emission, and also by an absence of a traditional afterglow. GRB 101225A, the Christmas Burst, is a prototype of such class. It has been suggested that BBD-GRBs could be observed after a merger in a binary system consisting of a neutron star and a Helium core of a main sequence star. Using detailed relativistic hydrodynamic numerical simulations we model the propagation of ultrarelativistic jets through the environments created by such mergers. In this paper we focus on explaining the emission properties of the jet evolution computing the whole radiative signature (both thermal and non-thermal) of the jet dynamical evolution. A comprehensive parameter study of the jet/environment interaction has been performed and synthetic spectra and light curves are compared with the observational data...

Cuesta-Martínez, Carlos F; Mimica, Petar; Thöne, Christina C; de Ugarte-Postigo, Antonio

2014-01-01T23:59:59.000Z

52

CDA6530: Performance Models of Computers and Networks Chapter 4: Using Matlab for Performance  

E-Print Network (OSTI)

CDA6530: Performance Models of Computers and Networks Chapter 4: Using Matlab for Performance Interpreted language, easy to learn Use it to facilitate our simulation projects A good tool to plot .eps for Latex #12;3 Introduction MatLab : Matrix Laboratory Numerical Computations with matrices

Zou, Cliff C.

53

Numerical Modeling At Coso Geothermal Area (2010) | Open Energy Information  

Open Energy Info (EERE)

10) 10) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Numerical Modeling At Coso Geothermal Area (2010) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Numerical Modeling Activity Date 2010 Usefulness useful DOE-funding Unknown Exploration Basis To determine conditions when fractures nucleate Notes A numerical model was developed using Poly3D to simulate the distribution and magnitude of stress concentration in the vicinity of the borehole floor, and determine the conditions under which petal-centerline fractures nucleate. As a whole, the simulations have demonstrated that a borehole under the stress boundary conditions present at the Coso 58A-10 borehole is able to amplify the stress concentration to produce tension below the

54

Fuel Performance Code Benchmark for Uncertainty Analysis in Light Water Reactor Modeling.  

E-Print Network (OSTI)

??Fuel performance codes are used in the design and safety analysis of light water reactors. The differences in the physical models and the numerics of… (more)

Blyth, Taylor

2012-01-01T23:59:59.000Z

55

Numerical Modeling At Dixie Valley Geothermal Area (Benoit, 1999...  

Open Energy Info (EERE)

be interpreted. A large geothermal flow test was performed where there was 6 geothermal wells flowing at once and 8 idle wells being monitored. The conceptual model developed...

56

Numerical modeling and experimental validation of uniform microchamber filling in centrifugal microfluidics  

E-Print Network (OSTI)

microfluidics Jonathan Siegrist,*a Mary Amasia,a Navdeep Singh,b Debjyoti Banerjeeb and Marc Madoua Received 1st analysis of microchamber filling in centrifugal microfluidics is presented. In the development of micro on centrifugal microfluidic platforms, numerical modeling using the Volume of Fluids method is performed

Banerjee, Debjyoti

57

Mercury's thermo-chemical evolution from numerical models constrained  

E-Print Network (OSTI)

Mercury's thermo-chemical evolution from numerical models constrained by MESSENGER observations Globe de Paris, France #12;Basics facts about Mercury · Semi-major axis: 0.39 AU · 3:2 spin Earth!) · Black body temperature: 440 K #12;Exploration of Mercury Mariner10 ·First spacecraft to use

Cerveny, Vlastislav

58

Numerical Modeling of Internal Tide Generation along the Hawaiian Ridge  

Science Journals Connector (OSTI)

Internal M2 tides near Hawaii are investigated with a two-dimensional, two-layer numerical model. It is seen that along the Hawaiian Ridge barotropic tidal energy is transformed into baroclinic internal tides that propagate in both northeast and ...

S. K. Kang; M. G. G. Foreman; W. R. Crawford; J. Y. Cherniawsky

2000-05-01T23:59:59.000Z

59

Numerical modeling of magnetohydrodynamic activity in the Swarthmore Spheromak Experiment  

E-Print Network (OSTI)

Numerical modeling of magnetohydrodynamic activity in the Swarthmore Spheromak Experiment V. S resistive magnetohydrodynamic MHD simulation are compared to experimental data from the Swarthmore Spheromak is shown to reproduce global equilibrium magnetic field profiles of the spheromaks as well as much

Brown, Michael R.

60

Friction versus dilation revisited: Insights from theoretical and numerical models  

E-Print Network (OSTI)

Friction versus dilation revisited: Insights from theoretical and numerical models N. Makedonska,1 controlled by the frictional strength of the fault gouge, a granular layer that accumulates between the fault friction coefficient) of such granular layers is the systems resistance to dilation, a byprocess

Einat, Aharonov

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While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

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

SciTech Connect

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

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

2008-06-01T23:59:59.000Z

62

Numerical Modeling At Coso Geothermal Area (1997) | Open Energy Information  

Open Energy Info (EERE)

7) 7) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Numerical Modeling Activity Date 1997 Usefulness useful DOE-funding Unknown Exploration Basis Develop tool to identify low velocity zones by modeling fault-zone guided waves of microearthquakes Notes A numerical method has been employed to simulate the guided-wave propagation from microearthquakes through the fault zone. By comparing observed and synthetic waveforms the fault-zone width and its P-wave and S-wave velocity structure have been estimated. It is suggested that the identification and modeling of guided waves is an effective tool to locate fracture-induced, low-velocity fault-zone structures in geothermal fields. References Lou, M.; Rial, J.A. ; Malin, P.E. (1 July 1997) Modeling

63

Parameter-oriented Visualization of a Modelica Model with a Numerical Data Integration Feature  

Science Journals Connector (OSTI)

Abstract In model-based development, designers develop models of complex engineered systems from combinations of building blocks, and then simulate the system behavior. The design process is assisted by multi-domain system modeling and simulation tools. These tools should be able to allow users to understand and validate the simulated behavior in terms of parameters and their dependencies with effective use of quantitative information, such as simulation results, experiments, and catalog data, in the system model. This paper proposes a tool that displays the parameters and their dependencies in system models written in Modelica, and integrates these models with numerical data. The latter feature is useful for evaluating quantitative performance.

Hitoshi Komoto; Shinsuke Kondoh; Keijiro Masui; Akira Tezuka

2014-01-01T23:59:59.000Z

64

Numerical Modeling At Coso Geothermal Area (2006) | Open Energy Information  

Open Energy Info (EERE)

2006) 2006) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Numerical Modeling Activity Date 2006 Usefulness useful DOE-funding Unknown Exploration Basis Determine areas of high permeability using isotope transport and exchange analysis Notes Finite element models of single-phase, variable-density fluid flow, conductive- convective heat transfer, fluid-rock isotope exchange, and groundwater residence times were developed. Using detailed seismic reflection data and geologic mapping, a regional cross-sectional model was constructed that extends laterally from the Sierra Nevada to Wildhorse Mesa, west of the Argus Range. The findings suggest that active faults and seismogenic zones in and around the Coso geothermal area have much higher

65

Numerical Modeling At Coso Geothermal Area (2007) | Open Energy Information  

Open Energy Info (EERE)

Coso Geothermal Area (2007) Coso Geothermal Area (2007) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Numerical Modeling At Coso Geothermal Area (2007) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Numerical Modeling Activity Date 2007 Usefulness not indicated DOE-funding Unknown Exploration Basis To determine the importance of fracture networks for fluid migration in tectonically active regions such as the Coso Range. Notes A finite element analysis is used to establish the 3D state of stress within the tectonic setting of the Coso Range. The mean and differential stress distributions are used to infer fluid flow vectors and second order fracture likelihood and orientation. The results show that the Coso Range

66

ASSIMILATION OF DOPPLER RADAR DATA INTO NUMERICAL WEATHER MODELS  

SciTech Connect

During the year 2008, the United States National Weather Service (NWS) completed an eight fold increase in sampling capability for weather radars to 250 m resolution. This increase is expected to improve warning lead times by detecting small scale features sooner with increased reliability; however, current NWS operational model domains utilize grid spacing an order of magnitude larger than the radar data resolution, and therefore the added resolution of radar data is not fully exploited. The assimilation of radar reflectivity and velocity data into high resolution numerical weather model forecasts where grid spacing is comparable to the radar data resolution was investigated under a Laboratory Directed Research and Development (LDRD) 'quick hit' grant to determine the impact of improved data resolution on model predictions with specific initial proof of concept application to daily Savannah River Site operations and emergency response. Development of software to process NWS radar reflectivity and radial velocity data was undertaken for assimilation of observations into numerical models. Data values within the radar data volume undergo automated quality control (QC) analysis routines developed in support of this project to eliminate empty/missing data points, decrease anomalous propagation values, and determine error thresholds by utilizing the calculated variances among data values. The Weather Research and Forecasting model (WRF) three dimensional variational data assimilation package (WRF-3DVAR) was used to incorporate the QC'ed radar data into input and boundary conditions. The lack of observational data in the vicinity of SRS available to NWS operational models signifies an important data void where radar observations can provide significant input. These observations greatly enhance the knowledge of storm structures and the environmental conditions which influence their development. As the increase in computational power and availability has made higher resolution real-time model simulations possible, the need to obtain observations to both initialize numerical models and verify their output has become increasingly important. The assimilation of high resolution radar observations therefore provides a vital component in the development and utility of numerical model forecasts for both weather forecasting and contaminant transport, including future opportunities to improve wet deposition computations explicitly.

Chiswell, S.; Buckley, R.

2009-01-15T23:59:59.000Z

67

Numerical studies of a simple Coulomb blockade model  

E-Print Network (OSTI)

simple model of the Coulomb blockade is studied. In this model, two interacting electrons tunnel in a one-dimensional structure with two barriers in series. The two-particle, time-dependent Schrodinger equation is solved numerically. It is found... tunneling by the other, and the inside electron tunnels out only after the outside electron tunnels a second time. The distribution of the charge density for the two electrons is shown in a series of three-dimensional figures as a function of time. Also...

Shao, Jianfeng

2012-06-07T23:59:59.000Z

68

Experimental and numerical evaluation of electromagnetic acoustic transducer performance on steel materials  

E-Print Network (OSTI)

Experimental and numerical evaluation of electromagnetic acoustic transducer performance on steel 2011 Keywords: Electromagnetic Acoustic Transducers Magnetostriction Lorentz force Steel a b s t r a c of the test object. A wide variety of steel materials is employed in many industrial applications, so

Nagy, Peter B.

69

Numerical heat conduction in hydrodynamical models of colliding hypersonic flows  

E-Print Network (OSTI)

Hydrodynamical models of colliding hypersonic flows are presented which explore the dependence of the resulting dynamics and the characteristics of the derived X-ray emission on numerical conduction and viscosity. For the purpose of our investigation we present models of colliding flow with plane-parallel and cylindrical divergence. Numerical conduction causes erroneous heating of gas across the contact discontinuity which has implications for the rate at which the gas cools. We find that the dynamics of the shocked gas and the resulting X-ray emission are strongly dependent on the contrast in the density and temperature either side of the contact discontinuity, these effects being strongest where the postshock gas of one flow behaves quasi-adiabatically while the postshock gas of the other flow is strongly radiative. Introducing additional numerical viscosity into the simulations has the effect of damping the growth of instabilities, which in some cases act to increase the volume of shocked gas and can re-he...

Parkin, E R

2010-01-01T23:59:59.000Z

70

Numerical Modeling At Coso Geothermal Area (1999) | Open Energy Information  

Open Energy Info (EERE)

9) 9) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Numerical Modeling Activity Date 1999 Usefulness not indicated DOE-funding Unknown Exploration Basis To determine three-dimensional P and S waves velocity structures Notes High precision P and S wave travel times for 2104 microearthquakes with focus <6 km are used in a non-linear inversion to derive high-resolution 3-D compressional and shear velocity structures at the Coso Geothermal Area. Block size for the inversion is 0.2 km horizontally and 0.5 km vertically and inversions are investigated in the upper 5 km of the geothermal area. Spatial resolution, calculated by synthetic modeling of a cross model at critical locations, is estimated to be 0.35 km for Vp and 0.5 km for V s . In the 2 km southwest Sugarloaf region, we found low V p

71

Numerical modeling of hydraulic fracture problem in permeable medium using cohesive zone model  

E-Print Network (OSTI)

Numerical modeling of hydraulic fracture problem in permeable medium using cohesive zone model-off dominated. We demonstrate the ability of our cohesive zone model in simulating the hydraulic fracture in all these propagation regimes. Keywords: Hydraulic fracture, Cohesive zone model, Finite element analysis, Hydro

Paris-Sud XI, Université de

72

Numerical Modeling of WECS at Ecole Centrale de Nantes  

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

LHEEA LHEEA CNRS UMR 6598 Laboratoire de recherche en Hydrodynamique Énergétique et Environnement Atmosphérique Numerical modelling of Wave Energy Converters at LHEEA Lab Ecole Centrale de Nantes (France) Alain H. CLEMENT Senior researcher Ocean Energy and Ocean Waves Group NREL MHK Workshop - Broomfield (CO) - 9-10 July 2012 LHEEA CNRS UMR 6598 Laboratoire de recherche en Hydrodynamique Énergétique et Environnement Atmosphérique NREL MHK Workshop - Broomfield (CO) - 9-10 July 2012 The Ocean Energy and Waves group @ LHEEA Lab. LHEEA Lab. : Hydrodynamics, Energetics and Atmospheric Environment Staff : 100, Director : Prof. Pierre Ferrant

73

A residence-time-based transport approach for the groundwater pathway in performance assessment models  

Science Journals Connector (OSTI)

This paper presents the theoretical development and numerical implementation of a new modeling approach for representing the groundwater pathway in risk assessment or performance assessment model of a contaminant transport system. The model developed ... Keywords: Groundwater pathway, Mixing model, Performance assessment, Residence time distribution

Bruce A. Robinson; Shaoping Chu

2013-03-01T23:59:59.000Z

74

Numerical Modeling of Transient Basin and Range Extensional Geothermal  

Open Energy Info (EERE)

Transient Basin and Range Extensional Geothermal Transient Basin and Range Extensional Geothermal Systems Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Paper: Numerical Modeling of Transient Basin and Range Extensional Geothermal Systems Abstract A suite of models utilizing a range of bulkrock permeabilities were developed to analyze thetransient behavior of basin and range extensionalgeothermal systems, and particularly, the evolution ofthe system temperature with time. Each modelconsists of two mountain ranges (~1 km relief fromthe valley floor) separated by a thick sequence (about4 km) of clastic sediments derived from the adjacentranges, and a relatively permeable, high angle faultthat functions as a conduit for subsurface fluids. Thisgeometry is typical of Basin and Range extensionalsystems.We

75

Numerical Modeling of the Nucleation Conditions of Petal-Centerline  

Open Energy Info (EERE)

the Nucleation Conditions of Petal-Centerline the Nucleation Conditions of Petal-Centerline Fractures below a Borehole Floor, A Sensitivity Study and Application to the Coso Geothermal Field Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: Numerical Modeling of the Nucleation Conditions of Petal-Centerline Fractures below a Borehole Floor, A Sensitivity Study and Application to the Coso Geothermal Field Details Activities (1) Areas (1) Regions (0) Abstract: A boundary element model using Poly3D© has been developed to investigate the conditions in which the stress concentration below the floor of a borehole can cause tensile stress necessary to nucleate petal-centerline fractures. The remote stress state, borehole geometry, and traction boundary conditions on the borehole surface are taken from direct

76

The Numerical Modelling Research and Development Division is responsible for research into and develop-  

E-Print Network (OSTI)

into and develop- ment of numerical weather prediction models and other meteorological applications, that are opera in the field of numerical weather prediction: atmospheric and oceanographic modelling, physical and statistical132 The Numerical Modelling Research and Development Division is responsible for research

Haak, Hein

77

Evaluating the ability of a numerical weather prediction model to forecast tracer concentrations during ETEX 2  

E-Print Network (OSTI)

Evaluating the ability of a numerical weather prediction model to forecast tracer concentrations an operational numerical weather prediction model to forecast air quality are also investigated. These potential a numerical weather prediction (NWP) model independently of the CTM. The NWP output is typically archived

Dacre, Helen

78

USING LEARNING MACHINES TO CREATE SOLAR RADIATION MAPS FROM NUMERICAL WEATHER PREDICTION MODELS,  

E-Print Network (OSTI)

USING LEARNING MACHINES TO CREATE SOLAR RADIATION MAPS FROM NUMERICAL WEATHER PREDICTION MODELS simulation by means of a Numerical Weather Prediction Model (NWP), Skiron. After that, we have made spatial solar resource map. 2.1. Meteorological simulation The numerical weather prediction model used is SKIRON

Paris-Sud XI, Université de

79

Numerical Modeling of Thermal EOR: Comprehensive Coupling of an AMR-Based Model  

E-Print Network (OSTI)

Numerical Modeling of Thermal EOR: Comprehensive Coupling of an AMR-Based Model of Thermal Fluid.renard@ifpen.fr * Corresponding author Résumé -- Modélisation numérique d'EOR thermique : couplage complet entre un modèle d of Thermal EOR: Comprehensive Coupling of an AMR-Based Model of Thermal Fluid Flow and Geomechanics

Paris-Sud XI, Université de

80

Mathematical and Numerical Techniques in Energy and Environmental Modeling  

E-Print Network (OSTI)

and transport of ground- water contaminants and to design in situ remediation strategies. Three basic problem and optimize remediation of groundwater contaminants. Toward that end, one must be able to pre- dict the performance of the reservoir under various remediation schemes. To do this, a model of the reservoir and its

Ewing, Richard E.

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


81

Statistical Performance Modeling of SRAMs  

E-Print Network (OSTI)

Yield analysis is a critical step in memory designs considering a variety of performance constraints. Traditional circuit level Monte-Carlo simulations for yield estimation of Static Random Access Memory (SRAM) cell is quite time consuming due...

Zhao, Chang

2011-02-22T23:59:59.000Z

82

ASSESSMENT OF ECONOMIC PERFORMANCE OF MODEL PREDICTIVE  

E-Print Network (OSTI)

ASSESSMENT OF ECONOMIC PERFORMANCE OF MODEL PREDICTIVE CONTROL THROUGH VARIANCE/CONSTRAINT TUNING advanced process control (APC) strategies to deal with multivariable constrained control problems with an ultimate objective towards economic optimization. Any attempt to evaluate MPC performance should therefore

Huang, Biao

83

Integrated Numerical Modeling Process for Evaluating Automobile Climate Control Systems  

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

FCC-70 FCC-70 Integrated Numerical Modeling Process for Evaluating Automobile Climate Control Systems John Rugh National Renewable Energy Laboratory Copyright © 2002 Society of Automotive Engineers, Inc. ABSTRACT The air-conditioning (A/C) system compressor load can significantly impact the fuel economy and tailpipe emissions of conventional and hybrid electric automobiles. With the increasing emphasis on fuel economy, it is clear that the A/C compressor load needs to be reduced. In order to accomplish this goal, more efficient climate control delivery systems and reduced peak soak temperatures will be necessary to reduce the impact of vehicle A/C systems on fuel economy and tailpipe emissions. Good analytical techniques are important in identifying promising concepts. The goal at

84

A numerical model of aerosol scavenging: Part 1, Microphysics parameterization  

SciTech Connect

We have developed a three-dimensional numerical model (OCTET) to simulate the dynamics and microphysics of clouds and the transport, diffusion and precipitation scavenging of aerosol particles. In this paper we describe the cloud microphysics and scavenging parameterizations. The representation of cloud microphysics is a bulk- water parameterization which includes water vapor and five types of hydrometeors (cloud droplets, rain drops, ice crystals, snow, and graupel). A parallel parameterization represents the scavenging interactions between pollutant particles and hydrometeors including collection of particles because of condensation nucleation, Brownian and phoretic attachment, and inertial capture, resuspension because of evaporation and sublimation; and transfer interactions where particles collected by one type of hydrometeor are transferred to another type of freezing, melting, accretion, riming and autoconversion.

Molenkamp, C.R.; Bradley, M.M.

1991-09-01T23:59:59.000Z

85

The Dynamics of Deterministic Chaos in Numerical Weather Prediction Models  

E-Print Network (OSTI)

Atmospheric weather systems are coherent structures consisting of discrete cloud cells forming patterns of rows/streets, mesoscale clusters and spiral bands which maintain their identity for the duration of their appreciable life times in the turbulent shear flow of the planetary Atmospheric Boundary Layer. The existence of coherent structures (seemingly systematic motion) in turbulent flows has been well established during the last 20 years of research in turbulence. Numerical weather prediction models based on the inherently non-linear Navier-Stokes equations do not give realistic forecasts because of the following inherent limitations: (1) the non-linear governing equations for atmospheric flows do not have exact analytic solutions and being sensitive to initial conditions give chaotic solutions characteristic of deterministic chaos (2) the governing equations do not incorporate the dynamical interactions and co-existence of the complete spectrum of turbulent fluctuations which form an integral part of the large coherent weather systems (3) limitations of available computer capacity necessitates severe truncation of the governing equations, thereby generating errors of approximations (4) the computer precision related roundoff errors magnify the earlier mentioned uncertainties exponentially with time and the model predictions become unrealistic. The accurate modelling of weather phenomena therefore requires alternative concepts and computational techniques. In this paper a universal theory of deterministic chaos applicable to the formation of coherent weather structures in the ABL is presented.

A. Mary Selvam

2003-10-07T23:59:59.000Z

86

Sandia National Laboratories: PV Performance Modeling Collaborative  

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

being pursued in this collaborative include: PVPMC Website: (http:pvpmc.org) Matlab(tm) PV Performance Modeling Toolbox (PVLIB Toolbox can be downloaded on http:...

87

Sustainable heat extraction from abandoned mine tunnels: A numerical model  

Science Journals Connector (OSTI)

Abandoned mines are often associated with enduring liabilities which involve significant costs for decades after the decommissioning of the mine. Using a decommissioned mine as a geothermal resource can offset the environmental costs by supplying green heat to the communities living in and around the mine area. In this paper a numerical assessment of geothermal heat extraction from underground mine workings using an open loop geothermal system is carried out. In this study our focus is on fully flooded mines where the heat flow from the rock mass to the mine cavities is dominantly controlled by conduction in the rock mass. The sustainable heat flux into the mine workings is assessed using a transient two-dimensional axisymmetric heat transfer model. Finite volume method is applied to solve the model and simulate the transient temperature fields in the rock mass and within the water (flowing through cavities). The model is capable of controlling the rate of heat extraction through continuous adjustment of the rate of water flow through the mine. Sustainable rate of heat extraction is calculated for seasonally varied heat loads and for different project life cycles. It is shown that with proper resource management each kilometre of a typical deep underground mine tunnel can produce about 150?kW of usable heat in a sustainable manner. The model is validated by comparing its results with other published models and realistic data available from Springhill mine Nova Scotia Canada. It is found that the sustainable heat extraction is controlled dominantly by virgin rock temperature thermal conductivity of the rock mass and seasonal heat load variations.

S. A. Ghoreishi Madiseh; Mory M. Ghomshei; F. P. Hassani; F. Abbasy

2012-01-01T23:59:59.000Z

88

Performance modeling in the design process  

SciTech Connect

Here, in capsule form, are some lessons learned trying to integrate performance modeling into the design process. Performance modeling should play a central role in system design; ignore it at your peril. The role of performance modeling is not the same in all design projects. Clearly specify performance goals and what factors will affect performance; they try to model those factors. Obtaining the data for the models can be a major problem; ongoing measurement projects are always worthwhile. Prototypes can be valuable data gathering tools if they are instrumented for this purpose. Anticipate the effect of environment on the system you are designing, and the effects of the system on the environment. Including the performance analyst on the design team from the beginning; if he is perceived as an outsider, he is more likely to be ignored, especially if decisions have already been made.

Alexander, W.; Brice, R.

1982-01-01T23:59:59.000Z

89

Performance monitoring and numerical modelling of a deep circular excavation  

E-Print Network (OSTI)

is then filled into the trench from the bottom and displaces the bentonite liquid, which is pumped from the top to the storage tanks. To create a tight wall primary panels are built with a spacing and secondary panels are added in-between. The joints have...

Schwamb, Tina

2014-07-01T23:59:59.000Z

90

Develop a numerical model to evaluate furrow irrigation performance  

E-Print Network (OSTI)

of the ASAE. in many parts of the world, increased attention must be given to improving surface irrigation efficiency by minimizing deep percolation and surface runoff. To improve existing surface irrigation systems, an evaluation of how irrigauon water... of the ASAE. in many parts of the world, increased attention must be given to improving surface irrigation efficiency by minimizing deep percolation and surface runoff. To improve existing surface irrigation systems, an evaluation of how irrigauon water...

Jnad, Ihab

2012-06-07T23:59:59.000Z

91

NUMERICAL MODELING OF SPACE PLASMA FLOWS / ASTRONUM-2007 ASP Conference Series, Vol. 385, c 2008  

E-Print Network (OSTI)

model The ENLIL (Sumerian god of wind) code is a numerical model for simulations of background solar- energetic-particles (SEP) models (Luhmann et al. 2004). 3. Coupling with empirical coronal models Accurate

California at Berkeley, University of

92

NUMERICAL MODELING OF DEFORMATION AND FRACTURE OF WOOD INCLUDING HETEROGENEITY AND ANISOTROPY  

E-Print Network (OSTI)

NUMERICAL MODELING OF DEFORMATION AND FRACTURE OF WOOD INCLUDING HETEROGENEITY AND ANISOTROPY John A. Nairn Wood Science & Engineering, Oregon State University, USA Abstract The challenge in numerical modeling of wood is to have the model closely match the structure of a real specimen. The model

Nairn, John A.

93

PORFLOW Modeling Supporting The H-Tank Farm Performance Assessment  

SciTech Connect

Numerical simulations of groundwater flow and contaminant transport in the vadose and saturated zones have been conducted using the PORFLOW code in support of an overall Performance Assessment (PA) of the H-Tank Farm. This report provides technical detail on selected aspects of PORFLOW model development and describes the structure of the associated electronic files. The PORFLOW models for the H-Tank Farm PA, Rev. 1 were updated with grout, solubility, and inventory changes. The aquifer model was refined. In addition, a set of flow sensitivity runs were performed to allow flow to be varied in the related probabilistic GoldSim models. The final PORFLOW concentration values are used as input into a GoldSim dose calculator.

Jordan, J. M.; Flach, G. P.; Westbrook, M. L.

2012-08-31T23:59:59.000Z

94

Representing Cloud Processing of Aerosol in Numerical Models  

SciTech Connect

The satellite imagery in Figure 1 provides dramatic examples of how aerosol influences the cloud field. Aerosol from ship exhaust can serve as nucleation centers in otherwise cloud-free regions, forming ship tracks (top image), or can enhance the reflectance/albedo in already cloudy regions. This image is a demonstration of the first indirect effect, in which changes in aerosol modulate cloud droplet radius and concentration, which influences albedo. It is thought that, through the effects it has on precipitation (drizzle), aerosol can also affect the structure and persistence of planetary boundary layer (PBL) clouds. Regions of cellular convection, or open pockets of cloudiness (bottom image) are thought to be remnants of strongly drizzling PBL clouds. Pockets of Open Cloudiness (POCs) (Stevens et al. 2005) or Albrecht's ''rifts'' are low cloud fraction regions characterized by anomalously low aerosol concentrations, implying they result from precipitation. These features may in fact be a demonstration of the second indirect effect. To accurately represent these clouds in numerical models, we have to treat the coupled cloud-aerosol system. We present the following series of mesoscale and large eddy simulation (LES) experiments to evaluate the important aspects of treating the coupled cloud-aerosol problem. 1. Drizzling and nondrizzling simulations demonstrate the effect of drizzle on a mesoscale forecast off the California coast. 2. LES experiments with explicit (bin) microphysics gauge the relative importance of the shape of the aerosol spectrum on the 3D dynamics and cloud structure. 3. Idealized mesoscale model simulations evaluate the relative roles of various processes, sources, and sinks.

Mechem, D.B.; Kogan, Y.L.

2005-03-18T23:59:59.000Z

95

Numerical modeling of an all vanadium redox flow battery.  

SciTech Connect

We develop a capability to simulate reduction-oxidation (redox) flow batteries in the Sierra Multi-Mechanics code base. Specifically, we focus on all-vanadium redox flow batteries; however, the capability is general in implementation and could be adopted to other chemistries. The electrochemical and porous flow models follow those developed in the recent publication by [28]. We review the model implemented in this work and its assumptions, and we show several verification cases including a binary electrolyte, and a battery half-cell. Then, we compare our model implementation with the experimental results shown in [28], with good agreement seen. Next, a sensitivity study is conducted for the major model parameters, which is beneficial in targeting specific features of the redox flow cell for improvement. Lastly, we simulate a three-dimensional version of the flow cell to determine the impact of plenum channels on the performance of the cell. Such channels are frequently seen in experimental designs where the current collector plates are borrowed from fuel cell designs. These designs use a serpentine channel etched into a solid collector plate.

Clausen, Jonathan R.; Brunini, Victor E.; Moffat, Harry K.; Martinez, Mario J.

2014-01-01T23:59:59.000Z

96

Performance evaluation of mixed model assembly lines  

Science Journals Connector (OSTI)

Performance evaluation for a Mixed Model Assembly Line Balancing Problem is complicated as a multitude of factors affect operational objectives while the objectives themselves can not be represented easily. This paper reports a study of the effect of four factors namely number of workstations, number of models, demand pattern and stochastic variability of task times on performance measures used for representing the operational objectives. Analysis of Variance and Signal to Noise (S/N) ratio have been used to evaluate the ability of performance measures in representing the operational objectives and to identify the impact of the factors/interactions on the behaviour of performance measures.

Jonnalagedda V.L. Venkatesh; Balaji M. Dabade

2010-01-01T23:59:59.000Z

97

Numerical evaluation of the thermal performances of roof-mounted radiant barriers  

E-Print Network (OSTI)

This paper deals with the thermal performances of roof-mounted radiant barriers. Using dynamic simulations of a mathematical model of a whole test cell including a radiant barrier installed between the roof top and the ceiling, the thermal performance of the roof is calculated. The mean method is more particularly used to assess the thermal resistance of the building component and lead to a value which is compared to the one obtained for a mass insulation product such as polyurethane foam. On a further stage, the thermal mathematical model is replaced by a thermo-aeraulic model which is used to evaluate the thermal resistance of the roof as a function of the airflow rate. The results shows a better performance of the roof in this new configuration, which is widely used in practice. Finally, the mathematical relation between the thermal resistance and the airflow rate is proposed.

Miranville, Frédéric; Lucas, Franck; Johan, Seriacaroupin

2014-01-01T23:59:59.000Z

98

An Evaluation of Tropical Cyclone Genesis Forecasts from Global Numerical Models  

Science Journals Connector (OSTI)

Tropical cyclone (TC) forecasts rely heavily on output from global numerical models. While considerable research has investigated the skill of various models with respect to track and intensity, few studies have considered how well global models ...

Daniel J. Halperin; Henry E. Fuelberg; Robert E. Hart; Joshua H. Cossuth; Philip Sura; Richard J. Pasch

2013-12-01T23:59:59.000Z

99

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

Science Journals Connector (OSTI)

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

Xiufeng Gao; Chengwei Zhang; Jinjia Wei; Bo Yu

2009-09-01T23:59:59.000Z

100

Numerical modeling of mountain building: Interplay between erosion law and crustal rheology  

E-Print Network (OSTI)

Numerical modeling of mountain building: Interplay between erosion law and crustal rheology V. Cattin, and J. Lave´ (2004), Numerical modeling of mountain building: Interplay between erosion law by a 2D finite element model that incorporates the rheological layering of the crust and the main

Demouchy, Sylvie

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


101

Numerical Weather Prediction (NWP) and hybrid ARMA/ANN model to predict global radiation  

E-Print Network (OSTI)

Numerical Weather Prediction (NWP) and hybrid ARMA/ANN model to predict global radiation Cyril a hybrid ARMA/ANN model and data issued from a numerical weather prediction model (ALADIN). We particularly@gmail.com #12;Abstract. We propose in this paper an original technique to predict global radiation using

Paris-Sud XI, Université de

102

An efficient numerical terrestrial scheme (ENTS) for fast earth system modelling  

E-Print Network (OSTI)

An efficient numerical terrestrial scheme (ENTS) for fast earth system modelling Mark Williamson Working Paper 83 #12;An efficient numerical terrestrial scheme (ENTS) for fast earth system modelling Mark for long time period simulations and large ensemble studies in Earth system models of intermediate

Williamson, Mark

103

A component infrastructure for performance and power modeling of parallel scientific applications  

Science Journals Connector (OSTI)

Characterizing the performance of scientific applications is essential for effective code optimization, both by compilers and by high-level adaptive numerical algorithms. While maximizing power efficiency is becoming increasingly important in current ... Keywords: CCA, common component architecture, components, performance modeling, power modeling

Van Bui; Boyana Norris; Kevin Huck; Lois Curfman McInnes; Li Li; Oscar Hernandez; Barbara Chapman

2008-10-01T23:59:59.000Z

104

Numerical Methods for Multiphysics, Multiphase, and Multicomponent Models for Fuel Cells.  

E-Print Network (OSTI)

??In this dissertation, we design and analyze efficient numerical methods for obtaining accurate solutions to model problems arising in fuel cells. A basic fuel cell… (more)

Xue, Guangri

2008-01-01T23:59:59.000Z

105

A numerical procedure to model and monitor CO2 sequestration in ...  

E-Print Network (OSTI)

Sep 7, 2012 ... analyze storage integrity, providing early warning should any leakage occurs. A numerical procedure to model and monitor CO2 sequestration ...

santos

106

Numerical tools for musical instruments acoustics: analysing nonlinear physical models using continuation  

E-Print Network (OSTI)

self-sustained oscillations. Several physical models (clarinet and saxophone) are formulated the dynamical properties of self-sustained musical instruments using tra- ditional numerical techniques

Boyer, Edmond

107

About Energy Savings Performance Contracting Model Documents  

Energy.gov (U.S. Department of Energy (DOE))

This page provides more information about the creation of the Energy Savings Performance Contracting (ESPC) Model Documents to be used when developing or updating procurement and contracting documents for ESPC projects and programs.

108

Numerical model of planar heterojunction organic solar cells  

Science Journals Connector (OSTI)

We present a numerical study of the effects of the energy barrier between the lowest unoccupied molecular orbital of the acceptor layer and the cathode, the thicknesses of the donor layer and acceptor layer on th...

ChaoZhu Ma; YingQuan Peng; RunSheng Wang; RongHua Li…

2011-07-01T23:59:59.000Z

109

Performance Engineering in the Community Atmosphere Model  

SciTech Connect

The Community Atmosphere Model (CAM) is the atmospheric component of the Community Climate System Model (CCSM) and is the primary consumer of computer resources in typical CCSM simulations. Performance engineering has been an important aspect of CAM development throughout its existence. This paper briefly summarizes these efforts and their impacts over the past five years.

Worley, P; Mirin, A; Drake, J; Sawyer, W

2006-05-30T23:59:59.000Z

110

Manual sorting of numerals in an inflective language for language modelling  

Science Journals Connector (OSTI)

In speech recognition systems language models are used to estimate the probabilities of word sequences. In this paper special emphasis is given to numerals---words that express numbers. One reason for this is the fact that in a practical application ... Keywords: Language models, Manual sorting, Numerals, Speech recognition

Gregor Donaj; Zdravko Ka?i?

2014-09-01T23:59:59.000Z

111

Numerical Early Warning Model Research of Landfill Gas Permeation and Diffusion Considering Flow-Temperature Coupling  

Science Journals Connector (OSTI)

Based on seepage mechanics in porous medium gas and heat transfer theory, numerical early warning model is established, which is on quantitative description of migration and release of landfill gas and penetration and diffusion of energy, and dynamic ... Keywords: component, landfill gas, flow-temperature coupling, gas pressure and temperature distribution, numerical early warning model

Xue Qiang; Feng Xia-ting; Ma Shi-jin; Zhou Xiao-jun

2009-10-01T23:59:59.000Z

112

Time Step Sensitivity of Nonlinear Atmospheric Models: Numerical Convergence, Truncation Error Growth, and Ensemble Design  

E-Print Network (OSTI)

1973; Oran and Boris 1987; Murray 1989; Gershenfeld 1999). Weather and climate prediction models, which to the initial conditions, which is a major source of uncertainty in Numerical Weather Prediction (NWP; eTime Step Sensitivity of Nonlinear Atmospheric Models: Numerical Convergence, Truncation Error

Judd, Kevin

113

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

E-Print Network (OSTI)

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

Kirby, James T.

114

A Parameterization of Heterogeneous Land Surfaces for Atmospheric Numerical Models and Its Impact on Regional Meteorology  

Science Journals Connector (OSTI)

Natural land surfaces are usually heterogeneous over the resolvable scales considered in atmospheric numerical models. Therefore, model surface parameterizations that assume surface homogeneity may fail to represent the surface forcing ...

R. Avissar; R. A. Pielke

1989-10-01T23:59:59.000Z

115

NUMERICAL ANALYSIS OF A STEEPEST-DESCENT PDE MODEL FOR SURFACE RELAXATION BELOW THE ROUGHENING  

E-Print Network (OSTI)

NUMERICAL ANALYSIS OF A STEEPEST-DESCENT PDE MODEL FOR SURFACE RELAXATION BELOW THE ROUGHENING addresses a widely-used PDE model for the relaxation of a crystalline surface below the roughening

116

Assessment of Wind Power Potential for Two Contrasting Coastlines of South Africa Using a Numerical Model  

Science Journals Connector (OSTI)

A two-dimensional numerical model is used to predict near surface wind velocities, and consequently wind power, for five distinct synoptic regimes for contrasting east and west coasts of South Africa. The model results suggest that no one ...

R. D. Diab; M. Garstang

1984-12-01T23:59:59.000Z

117

Non-smooth Dynamics Using Differential-algebraic Equations Perspective: Modeling and Numerical Solutions  

E-Print Network (OSTI)

mathematical tools. On the other hand, the approach based on differential-algebraic equations gives more insight into the constitutive assumptions of a chosen model and easier to obtain numerical solutions. Bingham-type models in which the force cannot...

Gotika, Priyanka

2012-02-14T23:59:59.000Z

118

A 3D numerical model for Kepler's supernova remnant  

Science Journals Connector (OSTI)

......28, 1428 Buenos Aires, Argentina 3 Facultad de Ciencias Exactas...Universidad de Buenos Aires, Argentina We present new 3D numerical...density of 103 and an explosion energy of 7-1050-erg. The obtained...the gas pressure. The total energy density E is given by where......

J. C. Toledo-Roy; A. Esquivel; P. F. Velázquez; E. M. Reynoso

2014-01-01T23:59:59.000Z

119

A 3D numerical model for Kepler's supernova remnant  

Science Journals Connector (OSTI)

......synthetic X-ray maps from the numerical...considering an AGB mass-loss rate...Mo-yr1, a wind terminal velocity of 10-km-s1...of the AGB wind mass-loss rate, terminal velocity and ISM density...out of the wind bubble considerably...X-ray emission maps, taking into......

J. C. Toledo-Roy; A. Esquivel; P. F. Velázquez; E. M. Reynoso

2014-01-01T23:59:59.000Z

120

Critical review of glass performance modeling  

SciTech Connect

Borosilicate glass is to be used for permanent disposal of high-level nuclear waste in a geologic repository. Mechanistic chemical models are used to predict the rate at which radionuclides will be released from the glass under repository conditions. The most successful and useful of these models link reaction path geochemical modeling programs with a glass dissolution rate law that is consistent with transition state theory. These models have been used to simulate several types of short-term laboratory tests of glass dissolution and to predict the long-term performance of the glass in a repository. Although mechanistically based, the current models are limited by a lack of unambiguous experimental support for some of their assumptions. The most severe problem of this type is the lack of an existing validated mechanism that controls long-term glass dissolution rates. Current models can be improved by performing carefully designed experiments and using the experimental results to validate the rate-controlling mechanisms implicit in the models. These models should be supported with long-term experiments to be used for model validation. The mechanistic basis of the models should be explored by using modern molecular simulations such as molecular orbital and molecular dynamics to investigate both the glass structure and its dissolution process.

Bourcier, W.L. [Lawrence Livermore National Lab., CA (United States)

1994-07-01T23:59:59.000Z

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


121

Numerical study of primary steam superheating effects on steam ejector flow and its pumping performance  

Science Journals Connector (OSTI)

Abstract The effects of primary steam superheating on steam condensation in nozzle and the performance of steam ejector were investigated using CFD (computational fluid dynamics) method. Using a wet steam model being proposed in our previous study, simulations based on the primary steam with five superheated levels were performed, and the results demonstrate the superheating operation of the primary steam weakens the spontaneous condensation intensity and postpones its occurrence within the nozzle vicinity. Due to the droplets nucleation refinement for the condensation of superheated steam, the mixing process between the primary and the secondary fluids is improved. Consequently, a higher entrainment ratio is achieved. However, the superheating operation may not exceed 20 K, as its contribution on entrainment ratio improvement is not as significant as 0 K–20 K superheating, and too much superheating will requires more energy as input, which is not a practical solution to further improve the steam ejector pumping performance.

Xiaodong Wang; Jingliang Dong; Ao Li; Hongjian Lei; Jiyuan Tu

2014-01-01T23:59:59.000Z

122

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

E-Print Network (OSTI)

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

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

2014-01-05T23:59:59.000Z

123

Modeling well performance in compartmentalized gas reservoirs  

E-Print Network (OSTI)

index in estimating reservoir performance. • The optimization routine is done with VBA using Excel solver. Model Assumptions • The reservoir is in stabilized flow under pseudo-steady state conditions at constant pressure with no aquifer influx... is matched with a type curve to predict field performance. Fetkovich Decline Type Curves 11 is based on analytical solutions to flow equations for production at constant BHP and include both transient and boundary dominated flow periods. These log...

Yusuf, Nurudeen

2008-10-10T23:59:59.000Z

124

Modeling well performance in compartmentalized gas reservoirs  

E-Print Network (OSTI)

index in estimating reservoir performance. ? The optimization routine is done with VBA using Excel solver. Model Assumptions ? The reservoir is in stabilized flow under pseudo-steady state conditions at constant pressure with no aquifer influx... is matched with a type curve to predict field performance. Fetkovich Decline Type Curves 11 is based on analytical solutions to flow equations for production at constant BHP and include both transient and boundary dominated flow periods. These log...

Yusuf, Nurudeen

2009-05-15T23:59:59.000Z

125

A Hydro-Thermo-Mechanical Numerical Model For Hdr Geothermal Reservoir  

Open Energy Info (EERE)

Hydro-Thermo-Mechanical Numerical Model For Hdr Geothermal Reservoir Hydro-Thermo-Mechanical Numerical Model For Hdr Geothermal Reservoir Evaluation Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Hydro-Thermo-Mechanical Numerical Model For Hdr Geothermal Reservoir Evaluation Details Activities (0) Areas (0) Regions (0) Abstract: A two-dimensional numerical model of coupled fluid flow, heat transfer and rock mechanics in naturally fractured rock is developed. The model is applicable to assessments of hot dry rock (HDR) geothermal reservoir characterisation experiments, and to the study of hydraulic stimulations and the heat extraction potential of HDR reservoirs. Modelling assumptions are based on the characteristics of the experimental HDR reservoir in the Carnmenellis granite in Cornwall, S. W. England. In

126

Climate Modeling using High-Performance Computing  

SciTech Connect

The Center for Applied Scientific Computing (CASC) and the LLNL Climate and Carbon Science Group of Energy and Environment (E and E) are working together to improve predictions of future climate by applying the best available computational methods and computer resources to this problem. Over the last decade, researchers at the Lawrence Livermore National Laboratory (LLNL) have developed a number of climate models that provide state-of-the-art simulations on a wide variety of massively parallel computers. We are now developing and applying a second generation of high-performance climate models. Through the addition of relevant physical processes, we are developing an earth systems modeling capability as well.

Mirin, A A

2007-02-05T23:59:59.000Z

127

Radionuclide release rates from spent fuel for performance assessment modeling  

SciTech Connect

In a scenario of aqueous transport from a high-level radioactive waste repository, the concentration of radionuclides in water in contact with the waste constitutes the source term for transport models, and as such represents a fundamental component of all performance assessment models. Many laboratory experiments have been done to characterize release rates and understand processes influencing radionuclide release rates from irradiated nuclear fuel. Natural analogues of these waste forms have been studied to obtain information regarding the long-term stability of potential waste forms in complex natural systems. This information from diverse sources must be brought together to develop and defend methods used to define source terms for performance assessment models. In this manuscript examples of measures of radionuclide release rates from spent nuclear fuel or analogues of nuclear fuel are presented. Each example represents a very different approach to obtaining a numerical measure and each has its limitations. There is no way to obtain an unambiguous measure of this or any parameter used in performance assessment codes for evaluating the effects of processes operative over many millennia. The examples are intended to suggest by example that in the absence of the ability to evaluate accuracy and precision, consistency of a broadly based set of data can be used as circumstantial evidence to defend the choice of parameters used in performance assessments.

Curtis, D.B.

1994-11-01T23:59:59.000Z

128

EVALUATION OF NUMERICAL WEATHER PREDICTION IN MODELING CLOUD-RADIATION INTERACTIONS OVER THE SOUTHERN GREAT PLAINS  

E-Print Network (OSTI)

EVALUATION OF NUMERICAL WEATHER PREDICTION IN MODELING CLOUD- RADIATION INTERACTIONS OVER.bnl.gov ABSTRACT Numerical weather prediction (NWP) is the basis for present-day weather forecasts, and NWP- and satellite- based observations over the Southern Great Plains to evaluate how well cloud

Johnson, Peter D.

129

Modeling Topaz-II system performance  

SciTech Connect

The US acquisition of the Topaz-11 in-core thermionic space reactor test system from Russia provides a good opportunity to perform a comparison of the Russian reported data and the results from computer codes such as MCNP (Ref. 3) and TFEHX (Ref. 4). The comparison study includes both neutronic and thermionic performance analyses. The Topaz II thermionic reactor is modeled with MCNP using actual Russian dimensions and parameters. The computation of the neutronic performance considers several important aspects such as the fuel enrichment and location of the thermionic fuel elements (TFES) in the reactor core. The neutronic analysis included the calculation of both radial and axial power distribution, which are then used in the TFEHX code for electrical performance. The reactor modeled consists of 37 single-cell TFEs distributed in a 13-cm-radius zirconium hydride block surrounded by 8 cm of beryllium metal reflector. The TFEs use 90% enriched [sup 235]U and molybdenum coated with a thin layer of [sup 184]W for emitter surface. Electrons emitted are captured by a collector surface with a gap filled with cesium vapor between the collector and emitter surfaces. The collector surface is electrically insulated with alumina. Liquid NaK provides the cooling system for the TFEs. The axial thermal power distribution is obtained by dividing the TFE into 40 axial nodes. Comparison of the true axial power distribution with that produced by electrical heaters was also performed.

Lee, H.H.; Klein, A.C. (Oregon State Univ., Corvallis (United States))

1993-01-01T23:59:59.000Z

130

Experimental and numerical modeling of convective proppant transport  

SciTech Connect

Slurry-transport and -settling experiments were conducted to improve current descriptions of proppant transport, and the results were used to formulate a new slurry-transport model incorporated into a fully 3D fracture simulator. The model was tested and verified vs. experimental observations of slurry transport in a 4 x 16-ft slot model. Results of the study indicate that proppant-slurry transport can be modeled accurately by accounting for the effects of single-particle settling, density-driven flow, particle-velocity profiles, and slurry rheology.

Barree, R.D. [Marathon Oil Co., Littleton, CO (United States); Conway, M.W. [Stim-Lab Inc., Duncan, OK (United States)

1995-03-01T23:59:59.000Z

131

A Hydro-Thermo-Mechanical Numerical Model For Hdr Geothermal...  

Open Energy Info (EERE)

to the most hydraulically conductive fractures in two orthogonal and vertical fracture sets. The mathematical model representing the hydro-mechanical interactions that are...

132

Numerical modelling of plasticity induced by transcranial magnetic stimulation  

Science Journals Connector (OSTI)

We use neural field theory and spike-timing dependent plasticity to make a simple but biophysically reasonable model of long-term plasticity changes in the cortex due to transcranial magnetic stimulation (TMS). We show how common TMS protocols can be ... Keywords: Modelling, Neural field theory, Plasticity, Theta burst stimulation, Transcranial magnetic stimulation

M. T. Wilson; D. P. Goodwin; P. W. Brownjohn; J. Shemmell; J. N. Reynolds

2014-06-01T23:59:59.000Z

133

Numerical modelling and analysis of a room temperature magnetic  

E-Print Network (OSTI)

are separated by channels of a heat transfer fluid. The time-dependent model solves the momentum and continuity equations of the flow of the heat transfer fluid and the coupled energy equations of the heat transfer and it was concluded that the model has energy conservation and that the solution is independent of the chosen grid

134

Polya Dobreva, Monio Kartalev NUMERICAL MODELING OF THE MAGNETOSPHERE  

E-Print Network (OSTI)

main objective is a description of the magnetosphere. Regions, formed in solar wind flow around magnetic field model Problem formulation Dirichlet #12;Input parameters solar wind parameters ­ Dp, By, Bz(IMF) Dst index dipole inclination (tilt angle) The parameters are needed by Tsyganenko model

Mustakerov, Ivan

135

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

SciTech Connect

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

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

1995-07-01T23:59:59.000Z

136

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

SciTech Connect

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

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

2014-06-01T23:59:59.000Z

137

System Advisor Model: Flat Plate Photovoltaic Performance Modeling Validation Report  

SciTech Connect

The System Advisor Model (SAM) is a free software tool that performs detailed analysis of both system performance and system financing for a variety of renewable energy technologies. This report provides detailed validation of the SAM flat plate photovoltaic performance model by comparing SAM-modeled PV system generation data to actual measured production data for nine PV systems ranging from 75 kW to greater than 25 MW in size. The results show strong agreement between SAM predictions and field data, with annualized prediction error below 3% for all fixed tilt cases and below 8% for all one axis tracked cases. The analysis concludes that snow cover and system outages are the primary sources of disagreement, and other deviations resulting from seasonal biases in the irradiation models and one axis tracking issues are discussed in detail.

Freeman, J.; Whitmore, J.; Kaffine, L.; Blair, N.; Dobos, A. P.

2013-12-01T23:59:59.000Z

138

A LARGE SCALE CONTINUUM-DISCRETE NUMERICAL MODELLING: APPLICATION TO OVERBURDEN DAMAGE OF A SALT CAVERN  

E-Print Network (OSTI)

CAVERN SOULEY Mountaka1 , MERCERAT Diego2 , DRIAD-LEBEAU Lynda1 , BERNARD Pascal2 1 INERIS, Ecole des collapse). KEYWORDS: cavern, numerical modelling, continuum-discrete, overburden, damage. RÃ?SUMÃ?: Dans l

Boyer, Edmond

139

Thermoelectric Generators for Automotive Waste Heat Recovery Systems Part I: Numerical Modeling  

E-Print Network (OSTI)

Thermoelectric Generators for Automotive Waste Heat Recovery Systems Part I: Numerical Modeling telluride TEMs. Key words: Thermoelectric generators, waste heat recovery, automotive exhaust, skutterudites bismuth telluride are considered for thermoelectric modules (TEMs) for conversion of waste heat from

Xu, Xianfan

140

Applying methods of numerical modeling to optimize a plasma burner of atmospheric pressure  

Science Journals Connector (OSTI)

The shape of a plasma burner is optimized by the methods of numerical modeling. Vortex-free flow is created in the burner merely at the expense of selecting the external tube profile rather than by introductio...

S. M. Perminov; V. N. Perminova…

1993-09-01T23:59:59.000Z

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


141

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

E-Print Network (OSTI)

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

Gonzalez-Ramirez, Noemi

2010-01-01T23:59:59.000Z

142

Numerical models of caldera deformation: Effects of multiphase and multicomponent hydrothermal fluid flow  

E-Print Network (OSTI)

and poroelastic deformation using a range of realistic physical parameters and processes. Hydrothermal fluidNumerical models of caldera deformation: Effects of multiphase and multicomponent hydrothermal. Although hydrothermal fluids have been discussed as a possible deformation agent, very few quantitative

143

Numerical Modeling of the Propagation Environment in the Atmospheric Boundary Layer over the Persian Gulf  

Science Journals Connector (OSTI)

Strong vertical gradients at the top of the atmospheric boundary layer affect the propagation of electromagnetic waves and can produce radar ducts. A three-dimensional, time-dependent, nonhydrostatic numerical model was used to simulate the ...

B. W. Atkinson; J-G. Li; R. S. Plant

2001-03-01T23:59:59.000Z

144

Numerical modeling of Persian Gulf salinity variations due to tidal effects  

Science Journals Connector (OSTI)

Numerical modeling of salinity changes in marine environment of Persian Gulf is investigated in this paper. Computer simulation ... in arbitrary and complex geometries, such as Persian Gulf domain. The results of...

S. R. Sabbagh Yazdi

2004-03-01T23:59:59.000Z

145

Numerically Solvable Model for Resonant Collisions of Electronswith Diatomic Molecules  

SciTech Connect

We describe a simple model for electron-molecule collisions that has one nuclear and one electronic degree of freedom and that can be solved to arbitrarily high precision, without making the Born-Oppenheimer approximation, by employing a combination of the exterior complex scaling method and a finite-element implementation of the discrete variable representation. We compare exact cross sections for vibrational excitation and dissociative attachment with results obtained using the local complex potential approximation as commonly applied in the ''boomerang'' model, and suggest how this two-dimensional model can be used to test the underpinnings of contemporary nonlocal approximations to resonant collisions.

Houfek, Karel; Rescigno, T.N.; McCurdy, C.W.

2006-01-27T23:59:59.000Z

146

Evaluation of Tropical Cyclone Center Identification Methods in Numerical Models  

Science Journals Connector (OSTI)

Identifying the center of a tropical cyclone in a high-resolution model simulation has a number of operational and research applications, including constructing a track, calculating azimuthal means and perturbations, and diagnosing vortex tilt. ...

Leon T. Nguyen; John Molinari; Diana Thomas

2014-11-01T23:59:59.000Z

147

A Numerical Model for the Equilibrium Shape of Electrified Raindrops  

Science Journals Connector (OSTI)

The model Beard Chuang, using the differential form of Laplace's formula, has been extended to raindrop shapes under the influence of vertical electric fields and drop charges. A finite volume method was used with a boundary-fitted coordinate ...

Catherine C. Chuang; Kenneth V. Beard

1990-06-01T23:59:59.000Z

148

A Two Pressure Numerical Model of Two Fluid Mixing \\Lambda  

E-Print Network (OSTI)

by comparison to the incompressible limit. For the purpose of this comparison, we present a newly obtained ana, for example in pipeline flow and the performance of inertial confinement fusion reactors; it is important behav­ ior of a multifluid mixture without direct simulation of all its microscopic details. From

New York at Stoney Brook, State University of

149

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

E-Print Network (OSTI)

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

Hoenninger, Corbett Reed

2012-06-07T23:59:59.000Z

150

Numerical modeling of hydrofracturing in a multilayer coal seam  

SciTech Connect

The mathematical model of the process for hydrodynamic fracturing in a multilayer coal seam is proposed. The model is based on the equation of continuity and Darcy's law. The filtration-temperature analogy allows solving the obtained non-linear, non-stationary problem in an axisymmetric statement for the pressure function as the heat-conductivity problem, by the finite-element method. The calculation results yield estimation of the radius of degassing borehole influence zone.

Nasedkina, A.A.; Trufanov, V.N. [Rostov State University, Rostov Na Donu (Russian Federation)

2006-01-15T23:59:59.000Z

151

A robotic crawler exploiting directional frictional interactions: experiments, numerics, and derivation of a reduced model  

E-Print Network (OSTI)

We present experimental and numerical results for a model crawler which is able to extract net positional changes from reciprocal shape changes, i.e. 'breathing-like' deformations, thanks to directional, frictional interactions with a textured solid substrate, mediated by flexible inclined feet. We also present a simple reduced model that captures the essential features of the kinematics and energetics of the gait, and compare its predictions with the results from experiments and from numerical simulations.

Giovanni Noselli; Antonio DeSimone

2014-08-26T23:59:59.000Z

152

Numerical modeling of fluid flow and heat transfer in a narrow Taylor-Couette-Poiseuille system  

E-Print Network (OSTI)

Numerical modeling of fluid flow and heat transfer in a narrow Taylor-Couette-Poiseuille system S [1, 2] widely validated in various rotor-stator cavities with throughflow [3­5] and heat transfer [6: RANS modeling, Reynolds Stress Model, Taylor-Couette-Poiseuille flow, turbulence, heat transfer. hal

Paris-Sud XI, Université de

153

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

E-Print Network (OSTI)

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

Paris-Sud XI, Université de

154

Foundation heat exchangers for residential ground source heat pump systems Numerical modeling and experimental validation  

SciTech Connect

A new type of ground heat exchanger that utilizes the excavation often made for basements or foundations has been proposed as an alternative to conventional ground heat exchangers. This article describes a numerical model that can be used to size these foundation heat exchanger (FHX) systems. The numerical model is a two-dimensional finite-volume model that considers a wide variety of factors, such as soil freezing and evapotranspiration. The FHX numerical model is validated with one year of experimental data collected at an experimental house located near Oak Ridge, Tennessee. The model shows good agreement with the experimental data-heat pump entering fluid temperatures typically within 1 C (1.8 F) - with minor discrepancies due to approximations, such as constant moisture content throughout the year, uniform evapotranspiration over the seasons, and lack of ground shading in the model.

Xing, Lu [Oklahoma State University; Cullin, James [Oklahoma State University; Spitler, Jeffery [Oklahoma State University; Im, Piljae [ORNL; Fisher, Daniel [Oklahoma State University

2011-01-01T23:59:59.000Z

155

A Numerical Model Without Truncation Error for a Steady-State Analysis of a Once-Through Steam Generator  

SciTech Connect

To overcome the drawbacks of conventional schemes for a numerical analysis of a steam generator (SG), an efficient numerical model has been developed to analyze the steady state of a once-through-type SG where the feedwater is heated to superheated steam. In the developed model, the temperature and enthalpy are defined at the boundary of a calculation cell, and the exact solutions for the temperature distribution in a calculation cell are utilized. This feature of the developed model frees calculation from the undesirable effects of numerical diffusion, and only a small number of nodes are required. Also, the developed model removes the ambiguity from the parameter values at the inlet and exit of a calculation.The BoSupSG-SS computer code was developed by using the analysis model, and it performed well with only three calculation nodes to analyze a superheated SG. The developed model can be effectively used for the cases where a fast one-dimensional calculation is required such as an SG or system design analysis.

Sim, Yoon Sub; Kim, Eui Kwang; Eoh, Jae Hyuk [Korea Atomic Energy Research Institute (Korea, Republic of)

2005-06-15T23:59:59.000Z

156

A numerical model of hydrothermal cooling and crustal accretion at a fast spreading mid-ocean ridge  

E-Print Network (OSTI)

: 7360 words, 11 figures. Keywords: Mid-ocean ridge processes; hydrothermal cooling; numerical modelA numerical model of hydrothermal cooling and crustal accretion at a fast spreading mid-ocean ridge present a steady state numerical representation of the sill model that explicitly includes hydrothermal

Toomey, Doug

157

Introduction Application of numerical models of ground water flow  

E-Print Network (OSTI)

(Portniaguine and Solomon 1998), and ground water temperature (Doussan et al. 1994). Compared to calibration depended on calibration methodology; models calibrated with multiple targets simulated q more accurately of Calibration Methodology on Ground Water Flow Predictions by James E. Saiers1, David P. Genereux2, and Carl H

Saiers, James

158

Joint physical and numerical modeling of water distribution networks.  

SciTech Connect

This report summarizes the experimental and modeling effort undertaken to understand solute mixing in a water distribution network conducted during the last year of a 3-year project. The experimental effort involves measurement of extent of mixing within different configurations of pipe networks, measurement of dynamic mixing in a single mixing tank, and measurement of dynamic solute mixing in a combined network-tank configuration. High resolution analysis of turbulence mixing is carried out via high speed photography as well as 3D finite-volume based Large Eddy Simulation turbulence models. Macroscopic mixing rules based on flow momentum balance are also explored, and in some cases, implemented in EPANET. A new version EPANET code was developed to yield better mixing predictions. The impact of a storage tank on pipe mixing in a combined pipe-tank network during diurnal fill-and-drain cycles is assessed. Preliminary comparison between dynamic pilot data and EPANET-BAM is also reported.

Zimmerman, Adam; O'Hern, Timothy John; Orear, Leslie Jr.; Kajder, Karen C.; Webb, Stephen Walter; Cappelle, Malynda A.; Khalsa, Siri Sahib; Wright, Jerome L.; Sun, Amy Cha-Tien; Chwirka, J. Benjamin; Hartenberger, Joel David; McKenna, Sean Andrew; van Bloemen Waanders, Bart Gustaaf; McGrath, Lucas K.; Ho, Clifford Kuofei

2009-01-01T23:59:59.000Z

159

Numerically Efficient Water Quality Modeling and Security Applications  

E-Print Network (OSTI)

to consider e ective tools and mitigation strategies to improve water network security. This work presents two components that have been integrated into EPA?s Water Security Toolkit, an open-source software package that includes a set of tools to help water... several advantages and potential uses that are aligned with current emerging water security applications. This computational framework is able to e ciently generate an explicit mathematical model that can be easily embedded into larger mathematical...

Mann, Angelica

2013-02-04T23:59:59.000Z

160

Two- and three-dimensional numerical models of internal tide generation at a continental slope  

Science Journals Connector (OSTI)

Some numerical models of internal tide generation at a continental slope are two-dimensional where the along-slope variation is neglected. The energy flux carried by internal tides computed using such two-dimensional models is often underestimated, compared with three-dimensional simulations of the same region, by a factor of 10 or more. The reason for this difference is investigated using both numerical and analytical models. It is shown that in numerical models, it is not the lack of the along-shelf forcing but the use of sponge or radiating conditions at the cross-shelf boundaries that leads to the severe underestimate of the offshore flux. To obtain realistic estimates of energy flux a three-dimensional model with an along-shelf scale of at least 5 internal tide wave lengths at the depth of maximum forcing is necessary.

K. Katsumata

2006-01-01T23:59:59.000Z

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


161

Global temperatures using satellite and numerical model assimilated data  

SciTech Connect

The Microwave Sounding Unit (MSU) aboard the National Oceanic and Atmospheric Administration (NOAA) series of polar orbiting satellites (TIROS-N to NOAA-11) have provided stable, precise measurements of vertically integrated, atmospheric temperature since December 1978. In this study, comparisons are made between the MSU channel measurements and those derived from the Global Data Assimilation System (GDAS) at the National Meteorological Center (NMC) over the period 1979 to 1990. Land areas rich in Radiosonde Observations (RAOBS) showed similar magnitudes of spatial variability between the NMC GDAS and the MSU temperatures. Excessive spatial variability can be noted in the GDAS over land areas where conventional data is poor. Over the ocean, however, the assimilation of satellite data into the model improves the spatial variability detected by the GDAS.

Basist, A.; Ropelewski, C.; Grody, N. (NOAA/NWS/NMC, Washington, DC (United States) NOAA/NESDIS, Washington, DC (United States))

1994-01-01T23:59:59.000Z

162

Numerical evaluation of the energetic performances of structured and random packed beds in regenerative thermal oxidizers  

Science Journals Connector (OSTI)

Regenerative thermal oxidizers (RTO) can be conveniently used to control volatile organic components (VOC) emissions, because of their thermal efficiency and cost effectiveness. In the RTO technology, beds of inert material are used in order to heat the polluted air by cooling burnt gases, through a sequence of cyclic operations which cut the fuel requirements. A computational 1D unsteady model, able to account for both structured and random packed bed regenerators, is developed and applied to realistic plant conditions. Process thermal efficiency and gas pressure drop are calculated as functions of the system geometry and operating parameters. The code can be usefully employed in the analysis and design of RTO systems and in order to choose the more suitable type of regenerator, structured or random packed bed (even considering various particle shapes). Energetic performances of both random and structured regenerators were compared, showing that the first ones exhibit a little higher thermal efficiency but also an elevated pressure drop, at a same value of exchange surface per unit volume of the bed. Random packed bed regenerators resulted less attractive from the energetic point of view and their usage is advisable if their lower cost satisfy economical requirements.

Mario Amelio; Pietropaolo Morrone

2007-01-01T23:59:59.000Z

163

An XFEM Model for Carbon Sequestration Journal: International Journal for Numerical Methods in Engineering  

E-Print Network (OSTI)

PeerReview Only An XFEM Model for Carbon Sequestration Journal: International Journal for Numerical method, Carbon Sequestration, Multiphase flow, XFEM, Multifield systems, Petrov-Galerkin httpScience (www.interscience.wiley.com). DOI: 10.1002/nme An XFEM Model for Carbon Sequestration Chris Ladubec

Gracie, Robert

164

Numerical and experimental validation of transient modelling for Scramjet active cooling with supercritical  

E-Print Network (OSTI)

Numerical and experimental validation of transient modelling for Scramjet active cooling of the engine. In order to simulate the behaviour of a complete actively cooled scramjet, a one for supercritical fuel under pyrolysis. This model is called RESPIRE (French acronym for Scramjet Cooling

Paris-Sud XI, Université de

165

NUMERICAL MODELING OF CIGS AND CdTe SOLAR CELLS: SETTING THE BASELINE  

E-Print Network (OSTI)

NUMERICAL MODELING OF CIGS AND CdTe SOLAR CELLS: SETTING THE BASELINE M. Gloeckler, A. Consequently specific baseline parameters for CIGS and CdTe are proposed. The modeling results important complications that are often found in experimental CIGS and CdTe solar cells. 1. INTRODUCTION

Sites, James R.

166

Laboratory experiments and numerical modeling of wave attenuation through artificial vegetation  

E-Print Network (OSTI)

? 5.1. Introduction to COULWAVE Boussinesq Model ................................................. 51? 5.2. Numerical Modeling of Vegetation Friction Factor .............................................. 53? CHAPTER VI - CONCLUSIONS... Additionally, vegetation directly increases the durability of shorelines through the root systems and enhances the storage of sand in dunes (Dean, 1978). Until recently the importance and function of wetlands was not well understood, and the amount...

Augustin, Lauren Nicole

2009-05-15T23:59:59.000Z

167

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

E-Print Network (OSTI)

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

Wisconsin at Madison, University of

168

Two-Dimensional Numerical Modeling of Radio-Frequency Ion Engine Discharge  

E-Print Network (OSTI)

Two-Dimensional Numerical Modeling of Radio-Frequency Ion Engine Discharge Michael Meng-Tsuan Tsay-Frequency Ion Engine Discharge Michael Meng-Tsuan Tsay, Manuel Martinez-Sanchez August 2010 SSL # 14 Modeling of Radio-Frequency Ion Engine Discharge by Michael Meng-Tsuan Tsay Submitted to the Department

169

From concentric eyewall to annular hurricane: A numerical study with the cloud-resolved WRF model  

E-Print Network (OSTI)

(secondary eyewall) in coincidence with a local tangential wind max- imum around the pre-existing eyewallFrom concentric eyewall to annular hurricane: A numerical study with the cloud-resolved WRF model Research and Forecasting (WRF) model, the transformation from a non- AH to an AH through a concentric

Wang, Bin

170

An active wave generating–absorbing boundary condition for VOF type numerical model  

Science Journals Connector (OSTI)

The objective of the present work is to discuss the implementation of an active wave generating–absorbing boundary condition for a numerical model based on the Volume Of Fluid (VOF) method for tracking free surfaces. First an overview of the development of VOF type models with special emphasis in the field of coastal engineering is given. A new type of numerical boundary condition for combined wave generation and absorption in the numerical model \\{VOFbreak2\\} is presented. The numerical boundary condition is based on an active wave absorption system that was first developed in the context of physical wave flume experiments, using a wave paddle. The method applies to regular and irregular waves. Velocities are measured at one location inside the computational domain. The reflected wave train is separated from the incident wave field in front of a structure by means of digital filtering and subsequent superposition of the measured velocity signals. The incident wave signal is corrected, so that the reflected wave is effectively absorbed at the boundary. The digital filters are derived theoretically and their practical design is discussed. The practical use of this numerical boundary condition is compared to the use of the absorption system in a physical wave flume. The effectiveness of the active wave generating–absorbing boundary condition finally is proved using analytical tests and numerical simulations with VOFbreak2.

Peter Troch; Julien De Rouck

1999-01-01T23:59:59.000Z

171

Estimation of the mean depth of boreal lakes for use in numerical weather prediction and climate modelling  

E-Print Network (OSTI)

in the numerical weather prediction (NWP) and climate models through parameterisation. For parameterisation, data. The effect of lakes should be parameterised in numerical weather prediction (NWP) and climate modellingEstimation of the mean depth of boreal lakes for use in numerical weather prediction and climate

Paris-Sud XI, Université de

172

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

E-Print Network (OSTI)

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

Grilli, Stéphan T.

173

A GIS-based open source pre-processor for georesources numerical modeling  

Science Journals Connector (OSTI)

Abstract TOUGH2 is an integral finite differences numerical simulator for non-isothermal multiphase flow in fractured porous media, which can manage complex spatial discretizations. Numerical simulation accuracy is affected, among other things, by grid resolution. Increasing the grid resolution requires computational and operating costs depending on the number of nodes and variables processed. The complexity of the management of the model increases when unstructured grids and local refinement are used. In order to improve the management and optimize the activities to update the model, an open source pre-processor has been developed using the open source codes GRASS GIS, \\{SQLite\\} and AMESH. Operations such as domain discretization, rock type assignment and mesh file generation have been automatized. Graphical interfaces allow for a user-friendly utilization. Operating errors and time required by pre-processing activities to generate and update locally refined unstructured grids have been reduced. Productivity in numerical modeling has been substantially increased.

P. Berry; S. Bonduá; V. Bortolotti; C. Cormio; E.M. Vasini

2014-01-01T23:59:59.000Z

174

Numerically Simulated Comparative Performance of a Scramjet and Shcramjet at Mach 11.  

E-Print Network (OSTI)

??This study investigates the design and aeropropulsive performance of a complete, hydrogen powered, shock-induced combustion ramjet (shcramjet) at a ?ight Mach number of 11 and… (more)

Chan, Jonathan

2010-01-01T23:59:59.000Z

175

Parareal in time 3D numerical solver for the LWR Benchmark neutron diffusion transient model  

E-Print Network (OSTI)

We present a parareal in time algorithm for the simulation of neutron diffusion transient model. The method is made efficient by means of a coarse solver defined with large time steps and steady control rods model. Using finite element for the space discretization, our implementation provides a good scalability of the algorithm. Numerical results show the efficiency of the parareal method on large light water reactor transient model corresponding to the Langenbuch-Maurer-Werner (LMW) benchmark [1].

Baudron, Anne-Marie A -M; Maday, Yvon; Riahi, Mohamed Kamel; Salomon, Julien

2014-01-01T23:59:59.000Z

176

Characterization of Texas lignite and numerical modeling of its in-situ gasification  

E-Print Network (OSTI)

CHARACTERIZATION OF TEXAS LIGNITE AND NUMERICAL MODELING OF ITS IN-SITU GASIFICATION A Thesis by YIH-JY WANG Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE December 1983 Major Subject: Geophysics CHARACTERIZATION OF TEXAS LIGNITE AND NUMERICAL MODELING OF ITS IN-SITU GASIFICATION A Thesis by YIH-JY WANG Approved as to style and content by: James E. Russell (Chairman of Committee) M. Caputo...

Wang, Yih-Jy

2012-06-07T23:59:59.000Z

177

A general numerical solution of dispersion relations for the nuclear optical model  

E-Print Network (OSTI)

A general numerical solution of the dispersion integral relation between the real and the imaginary parts of the nuclear optical potential is presented. Fast convergence is achieved by means of the Gauss-Legendre integration method, which offers accuracy, easiness of implementation and generality for dispersive optical model calculations. The use of this numerical integration method in the optical-model parameter search codes allows for a fast and accurate dispersive analysis. PACS number(s): 11.55.Fv, 24.10.Ht, 02.60.Jh

Roberto Capote; Alberto Molina; Jose Manuel Quesada

2001-05-09T23:59:59.000Z

178

Proceedings of the Numerical Modeling for Underground Nuclear Test Monitoring Symposium  

SciTech Connect

The purpose of the meeting was to discuss the state-of-the-art in numerical simulations of nuclear explosion phenomenology with applications to test ban monitoring. We focused on the uniqueness of model fits to data, the measurement and characterization of material response models, advanced modeling techniques, and applications of modeling to monitoring problems. The second goal of the symposium was to establish a dialogue between seismologists and explosion-source code calculators. The meeting was divided into five main sessions: explosion source phenomenology, material response modeling, numerical simulations, the seismic source, and phenomenology from near source to far field. We feel the symposium reached many of its goals. Individual papers submitted at the conference are indexed separately on the data base.

Taylor, S.R.; Kamm, J.R. [eds.

1993-11-01T23:59:59.000Z

179

Formal modelling of organisational goals based on performance indicators  

Science Journals Connector (OSTI)

Every organisation exists or is created for the achievement of one or more goals. To ensure continued success, the organisation should monitor its performance with respect to the formulated goals. In practice the performance of an organisation is often ... Keywords: Enterprise architectures, Formal modelling, Formal verification, Goals, Mathematical logic, Organisation modelling, Performance evaluation, Performance indicators

Viara Popova; Alexei Sharpanskykh

2011-04-01T23:59:59.000Z

180

Numerical modeling of heat transfer and fluid flow in rotor-stator cavities with throughflow  

E-Print Network (OSTI)

Numerical modeling of heat transfer and fluid flow in rotor-stator cavities with throughflow S in a rotor-stator cavity subjected to a superimposed throughflow with heat transfer. Nu- merical predictions field from the heat transfer process. The turbulent flux is approximated by a gradient hypothesis

Boyer, Edmond

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


181

Numerical Modeling and Experimental Study of Combustion and Soot Formation in a Direct Injection Diesel Engine  

Science Journals Connector (OSTI)

Numerical Modeling and Experimental Study of Combustion and Soot Formation in a Direct Injection Diesel Engine ... The major problems associated with diesel engines are the high levels of nitrogen oxides (NOX) and particulate emissions. ... (11)?Flagan, R. C.; Seinfeld, J. H. Fundamentals of Air Pollution Engineering; Prentice Hall Inc.:? New York, 1988. ...

T. L. Chan; X. B. Cheng

2007-04-10T23:59:59.000Z

182

Numerical Modeling of Nonlinear Surface Waves caused by Surface Effect Ships Dynamics and Kinematics  

E-Print Network (OSTI)

Numerical Modeling of Nonlinear Surface Waves caused by Surface Effect Ships Dynamics problems, particularly for high-speed Surface Effect Ships (SES) such as the recently proposed Harley FastShip and/or a surface-piercing body (ship), within the framework of potential flow theory. The three

Grilli, Stéphan T.

183

An improved numerical scheme for a coupled system to model soil erosion and polydispersed sediments transport  

E-Print Network (OSTI)

An improved numerical scheme for a coupled system to model soil erosion and polydispersed sediments, the positivity of both water depth and sediment concentrations. Recently, a well-balanced MUSCL-Hancock scheme step is required to ensure the positivity of sediment concentrations. The main result of this paper

Boyer, Edmond

184

LABORATORY OBSERVATIONS AND NUMERICAL MODELING OF THE EFFECTS OF AN ARRAY OF WAVE ENERGY CONVERTERS  

E-Print Network (OSTI)

1 LABORATORY OBSERVATIONS AND NUMERICAL MODELING OF THE EFFECTS OF AN ARRAY OF WAVE ENERGY of wave energy converters (WECs) on water waves through the analysis of extensive laboratory experiments absorption is a reasonable predictor of the effect of WECs on the far field. Keywords: wave- energy; spectral

Haller, Merrick

185

Numerical modeling of extreme rogue waves generated by directional energy focusing  

E-Print Network (OSTI)

Numerical modeling of extreme rogue waves generated by directional energy focusing Christophe angle of directional energy focusing. We find that an over- turning rogue wave can have different are characterized by their brief occurrence in space and time, resulting from a local focusing of wave energy

Grilli, Stéphan T.

186

Mathematical formulation and numerical modeling of wax deposition in pipelines from enthalpyporosity approach  

E-Print Network (OSTI)

Mathematical formulation and numerical modeling of wax deposition in pipelines from enthalpy and in the North Sea, the deposition of wax crystals in oil and gas pipelines becomes a major concern operational complexities. To pre- vent blockage of pipelines, wax deposits should be removed periodically

Firoozabadi, Abbas

187

NUMERICAL MODELING OF 3D ORGANIC SOLAR CELLS Presented to the  

E-Print Network (OSTI)

NUMERICAL MODELING OF 3D ORGANIC SOLAR CELLS _______________ A Thesis Presented to the Faculty Solar Cells by Anurag Kaushik Master of Science in Electrical Engineering San Diego State University and nanofabrication technologies offer a unique opportunity for meshing it with organic PV cell technology

Kassegne, Samuel Kinde

188

Modification of the Physics and Numerics in a Third-Generation Ocean Wave Model  

Science Journals Connector (OSTI)

The ocean wave model WAM was recently upgraded to improve the coupling between the sea state and the air flow and, in particular, enhance the growth of young wind sea over that of old wind sea. Prior to this change, numerous validations of the ...

Leslie C. Bender

1996-06-01T23:59:59.000Z

189

January 2, 2008 Numerical modeling of the effect of carbon dioxide  

E-Print Network (OSTI)

January 2, 2008 Numerical modeling of the effect of carbon dioxide sequestration on the rate souterrain de dioxyde de carbone sur la déformation des calcaires par dissolution sous contrainte: résultats;Abstract When carbon dioxide (CO2) is injected into an aquifer or a depleted geological reservoir, its

Boyer, Edmond

190

MODELING AND ADAPTIVE NUMERICAL TECHNIQUES FOR OXI-DATION OF CERAMIC COMPOSITES  

E-Print Network (OSTI)

. INTRODUCTION Oxidation shortens the life of ceramic matrix composites by, e.g., chang- ing the elasticMODELING AND ADAPTIVE NUMERICAL TECHNIQUES FOR OXI- DATION OF CERAMIC COMPOSITES S. Adjerid, M. Ai reaction 1-3 . Composite materials are protected by coatings; however, cracks that form as a result

Adjerid, Slimane

191

Numerical modeling of short pulse laser interaction with Au nanoparticle surrounded by water  

E-Print Network (OSTI)

for femtosecond laser excitation and time-resolved X-ray probing of gold nanoparticles demonstrates that the vaporNumerical modeling of short pulse laser interaction with Au nanoparticle surrounded by water Alexey, University of Virginia, USA Available online 3 February 2007 Abstract Short pulse laser interaction

Zhigilei, Leonid V.

192

COMPUTATIONAL CHALLENGES IN THE NUMERICAL TREATMENT OF LARGE AIR POLLUTION MODELS  

E-Print Network (OSTI)

COMPUTATIONAL CHALLENGES IN THE NUMERICAL TREATMENT OF LARGE AIR POLLUTION MODELS I. DIMOV , K. GEORGIEVy, TZ. OSTROMSKY , R. J. VAN DER PASz, AND Z. ZLATEVx Abstract. The air pollution, and especially the reduction of the air pollution to some acceptable levels, is an important environmental problem, which

Dimov, Ivan

193

Mathematical, physical and numerical principles essential for models of turbulent mixing  

SciTech Connect

We propose mathematical, physical and numerical principles which are important for the modeling of turbulent mixing, especially the classical and well studied Rayleigh-Taylor and Richtmyer-Meshkov instabilities which involve acceleration driven mixing of a fluid discontinuity layer, by a steady accerleration or an impulsive force.

Sharp, David Howland [Los Alamos National Laboratory; Lim, Hyunkyung [STONY BROOK UNIV; Yu, Yan [STONY BROOK UNIV; Glimm, James G [STONY BROOK UNIV

2009-01-01T23:59:59.000Z

194

NUMERICAL VERIFICATION OF THE RELAP-7 CORE CHANNEL SINGLE-PHASE MODEL  

SciTech Connect

The RELAP-7 code is the next generation of nuclear reactor system safety analysis code being developed at the Idaho National Laboratory (INL). All the physics in RELAP-7 are fully coupled and the errors resulted from the traditional operator-splitting approach are eliminated. By using 2nd order methods in both time and space and eliminating operator-splitting errors, the numerical error of RELAP-7 can be minimized. Numerical verification is the process to verify the orders of numerical methods. It is an important part of modern verification and validation process. The core channel component in RELAP-7 is designed to simulate coolant flow as well as the conjugated heat transfer between coolant flow and the fuel rod. A special treatment at fuel centerline to avoid numerical singularity for the cylindrical heat conduction in the continuous finite element mesh is discussed. One steady state test case and one fast power up transient test case are utilized for the verification of the core channel model with single-phase flow. Analytical solution for the fuel pin temperature and figures of merit such as peak clad temperature and peak fuel temperature are used to define numerical errors. These cases prove that the mass and energy are well conserved and 2nd order convergence rates for both time and space are achieved in the core channel model.

Haihua Zhao; Ling Zou; Hongbin Zhang; Richard Martineau

2014-06-01T23:59:59.000Z

195

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

E-Print Network (OSTI)

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

Zahn, Matthias

196

Numerical and Experimental Investigation into Propulsion and Cavitation Performance of Marine Propeller  

Science Journals Connector (OSTI)

This paper discusses the application of the CFD to transitional and cavitating flow around marine propellers. Especially the emphasis is put on the adaption of the 3 equations turbulence model for the non-cavi...

Nobuhiro Hasuike; Shosaburo Yamasaki…

2013-01-01T23:59:59.000Z

197

Performance Prediction for Parallel Numerical Software on the White Rose Grid  

E-Print Network (OSTI)

and Peter K. Jimack School of Computing, University of Leeds, UK {roman,pkj}@comp.leeds.ac.uk Abstract. Since different computer architectures have different performance characteristics, different levels automatic pre- dictive capabilities that will allow optimal de- cisions to be made concerning the selection

Jimack, Peter

198

Theory and numerical modeling of the accelerated expansion of laser-ablated materials near a solid surface  

Science Journals Connector (OSTI)

A self-similar theory and numerical hydrodynamic modeling is developed to investigate the effects of dynamic source and partial ionization on the acceleration of the unsteady expansion of laser-ablated material near a solid target surface. The dynamic source effect accelerates the expansion in the direction perpendicular to the target surface, while the dynamic partial ionization effect accelerates the expansion in all directions. The vaporized material during laser ablation provides a nonadiabatic dynamic source at the target surface into the unsteady expanding fluid. For studying the dynamic source effect, the self-similar theory begins with an assumed profile of plume velocity, u=v/vm=?+(1-?)?, where vm is the maximum expansion velocity, ? is a constant, and ?=x/vmt. The resultant profiles of plume density and plume temperature are derived. The relations obtained from the conservations of mass, momentum, and energy, respectively, all show that the maximum expansion velocity is inversely proportional to ?, where 1-? is the slope of plume velocity profile. The numerical hydrodynamic simulation is performed with the Rusanov method and the Newton Raphson method. The profiles and scalings obtained from numerical hydrodynamic modeling are in good agreement with the theory. The dynamic partial ionization requires ionization energy from the heat at the expansion front, and thus reduces the increase of front temperature. The reduction of thermal motion would increase the flow velocity to conserve the momentum. This dynamic partial ionization effect is studied with the numerical hydrodynamic simulation including the Saha equation. With these effects, ? is reduced from its value of conventional free expansion. This reduction on ? increases the flow velocity slope, decreases the flow velocity near the surface, and reduces the thermal motion of plume, such that the maximum expansion velocity is significantly increased over that found from conventional models. The result may provide an explanation for experimental observations of high-expansion front velocities even at low-laser fluence.

K. R. Chen; T. C. King; J. H. Hes; J. N. Leboeuf; D. B. Geohegan; R. F. Wood; A. A. Puretzky; J. M. Donato

1999-09-15T23:59:59.000Z

199

Software performance antipatterns: modeling and analysis  

Science Journals Connector (OSTI)

The problem of capturing performance problems is critical in the software design, mostly because the results of performance analysis (i.e. mean values, variances, and probability distributions) are difficult to be interpreted for providing feedback to ... Keywords: antipatterns, design alternatives, feedback generation, performance evaluation, software architecture

Vittorio Cortellessa; Antinisca Di Marco; Catia Trubiani

2012-06-01T23:59:59.000Z

200

Numerical study of the effects of upstream flow condition upon orifice flow meter performance  

SciTech Connect

Recent experimental work has shown that when the mean velocity profile upstream of an orifice plate has a deficit on the centerline and higher velocities at the outer edges of the pipe, the pressure drop across the orifice is greater than if the flow upstream is fully developed. It is proposed that this increase in [Delta]P is directly correlated with the radial distribution of momentum upstream of the orifice plate. In an effort to investigate how the upstream flow condition affects the pressure distribution along the pipe wall and to determine if the hypothesis is correct, Creare.X Inc. 's FLUENT numerical analysis program was used to simulate the effects. Two [beta] ratios (0.50 and 0.75) have been considered with various mean velocity inlet profiles. Inlet profiles include the 1/16th, 1/7th, 1/8th, 1/9th and 1/10th power law power law, uniform flow, and two linear distributions. The results indicate that there is a correlation between the second and third-order moments of momentum and the value of the discharge coefficient. This empirical correlation, after being fully verified by experimental data, can be used to estimate the change in the coefficient of discharge given the inlet velocity profile.

Morrison, G.L.; Panak, D.L.; DeOtte, R.E. Jr. (Texas A and M Univ., College Station, TX (United States). Mechanical Engineering Dept.)

1993-11-01T23:59:59.000Z

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


201

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

E-Print Network (OSTI)

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

Bourgeat, Alain; Smai, Farid

2010-01-01T23:59:59.000Z

202

Experimental and numerical investigation on air-side performance of fin-and-tube heat exchangers with various fin patterns  

SciTech Connect

Air-side heat transfer and friction characteristics of five kinds of fin-and-tube heat exchangers, with the number of tube rows (N = 12) and the diameter of tubes (D{sub o} = 18 mm), have been experimentally investigated. The test samples consist of five types of fin configurations: crimped spiral fin, plain fin, slit fin, fin with delta-wing longitudinal vortex generators (VGs) and mixed fin with front 6-row vortex-generator fin and rear 6-row slit fin. The heat transfer and friction factor correlations for different types of heat exchangers were obtained with the Reynolds numbers ranging from 4000 to 10000. It was found that crimped spiral fin provides higher heat transfer and pressure drop than the other four fins. The air-side performance of heat exchangers with the above five fins has been evaluated under three sets of criteria and it was shown that the heat exchanger with mixed fin (front vortex-generator fin and rear slit fin) has better performance than that with fin with delta-wing vortex generators, and the slit fin offers best heat transfer performance at high Reynolds numbers. Based on the correlations of numerical data, Genetic Algorithm optimization was carried out, and the optimization results indicated that the increase of VG attack angle or length, or decrease of VG height may enhance the performance of vortex-generator fin. The heat transfer performances for optimized vortex-generator fin and slit fin at hand have been compared with numerical method. (author)

Tang, L.H.; Zeng, M.; Wang, Q.W. [State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049 (China)

2009-07-15T23:59:59.000Z

203

Numerical estimation model of energy conversion for small hybrid solar–wind system  

Science Journals Connector (OSTI)

This article presents a numerical model which can estimate the energy conversions of separate and hybrid solar–wind systems under variable weather. The model integrates the equations associated with the characteristics of photovoltaic generation, wind energy conversion, energy balance, and battery bank, and uses the local database for radiation, wind speed, and ambient temperature. Once the equation associated with the characteristics of load is given, the numerical model can estimate the monthly and yearly powers output of the separate and hybrid solar–wind systems provided with different configurations. As a fundamental research, the presentations of daily profiles of solar radiation, wind energy, and ambient temperature are explained in detail, and the combination of the characteristics of wind energy conversion and battery bank is determined. The condition of hybrid action is shown, and the solutions are certain to be found. The operation strategies of separate and hybrid systems are also presented.

Shun Ching Lee

2012-01-01T23:59:59.000Z

204

Low Temperature Performance Characterization & Modeling | Department...  

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

Merit Review and Peer Evaluation Meeting, May 18-22, 2009 -- Washington D.C. esp04jansen.pdf More Documents & Publications Low Temperature Performance Characterization...

205

Modelling and simulating fire tube boiler performance  

E-Print Network (OSTI)

A model for a flue gas boiler covering the flue gas and the water-/steam side has been formulated. The model has been formulated as a number of sub models that are merged into an overall model for the complete boiler. Sub models have been defined for the furnace, the convection zone (split in 2: a zone submerged in water and a zone covered by steam), a model for the material in the boiler (the steel) and 2 models for resp. the water/steam zone (the boiling) and the steam. The dynamic model has been developed as a number of Differential-Algebraic-Equation system (DAE). Subsequently MatLab/Simulink has been applied for carrying out the simulations. To be able to verify the simulated results an experiments has been carried out on a full scale boiler plant.

Kim Sørensen; Claus M. S. Karstensen; Thomas Condra; Niels Houbak

206

Applying High Performance Computing to Analyzing by Probabilistic Model Checking  

E-Print Network (OSTI)

Applying High Performance Computing to Analyzing by Probabilistic Model Checking Mobile Cellular on the use of high performance computing in order to analyze with the proba- bilistic model checker PRISM. The Figure Generation Script 22 2 #12;1. Introduction We report in this paper on the use of high performance

Schneider, Carsten

207

Using GIS and numerical modeling to assess subsidence over abandoned mines  

SciTech Connect

The US Bureau of Mines (USBM) has been developing techniques to assess surface subsidence over abandoned coal mines. One technique has involved estimation of stress acting on every pillar of an abandoned mine then comparing it to pillar strength and floor bearing capacity. This required computations for several thousand pillars for one mine. Mine maps are digitized and saved as a computer drawing file. Then the tributary area loading each pillar was determined graphically and outlined. Geographic Information System (GIS) software was used to compute the ratio of pillar area to tributary area for each pillar and then divide the average overburden stress by this ratio to compute an estimated pillar stress. Numerical modeling was then used to analyze a two-dimensional cross section of the overburden and mine, and provide an independent estimate of stresses. Based on published data for floor bearing capacity and pillar load capacity, GIS was used to perform a mine-wide classification of pillars according to stress level. An example of this analysis and classification is presented in this paper for an abandoned coal mine in the Illinois Basin. The mine had been operated in the Herrin No. 6 Seam at a depth of 60 in with an average overburden stress of 1.4 MPa. It was found that pillars with estimated stresses greater than 5 MPa correlated with historical subsidence events. Due to the greater detail considered in this approach, it provides a fundamental basis for the assessment of subsidence risk since it incorporates the geometry of mine pillars and entries as well as the ultimate strength of the pillars and floor.

O`Connor, K.M. [GeoTDR, Inc., Apple Valley, MN (United States); Siekmeier, J.A. [Braun Intertec Corp., Minneapolis, MN (United States); Stache, J.

1996-12-31T23:59:59.000Z

208

A Knowledge Management Platform for Infrastructure Performance Modeling  

E-Print Network (OSTI)

Transportation Centers Program, in the interest of information exchange. The U.S. Government assumes no liability, utilization, evaluation and selection of performance models. Thus, the objective of the study is to build the capabilities of their own models. The platform advances infrastructure performance modeling because analysts

209

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

Science Journals Connector (OSTI)

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

Mohammad Lutfi Othman, Ishak Aris, Noor Izzri Abdul Wahab

2014-06-01T23:59:59.000Z

210

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

E-Print Network (OSTI)

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

d'Orléans, Université

211

Mathematical modelling approach for determining optimal machining parameters in turning with computer numerical control (CNC) machines  

Science Journals Connector (OSTI)

Due to advancement in the manufacturing technology the application of computer numerical control (CNC) machines have increased manifolds. The determination of machining parameters for optimal results in machining is a part of computer aided process planning. In computer numerical control (CNC) machining, determining optimum or appropriate cutting parameters can minimise machining errors such as tool breakage, tool deflection and tool wear, thus yielding a high productivity or minimum cost. Different mathematical models have been proposed by various researchers in the past for the determination of optimal machining parameters. The present paper attempt's to review the literature regarding 'machining parameter optimisation' for turning operation in CNC machines. Diverse contributing and important factors in mathematical modelling like, the economic criteria's, single and multi-pass turning, optimisation techniques and practical constraints deployed have been considered. A detailed discussion is presented regarding the topic and in the end conclusions are drawn.

Bhaskar Naithani; Santram Chauhan

2012-01-01T23:59:59.000Z

212

Degradation Pathway Models for Photovoltaics Module Lifetime Performance  

E-Print Network (OSTI)

Degradation Pathway Models for Photovoltaics Module Lifetime Performance Nicholas R. Wheeler, Laura data from Underwriter Labs, featuring measurements taken on 18 identical photovoltaic (PV) modules in modules and their effects on module performance over lifetime. Index Terms--photovoltaics, statistical

Rollins, Andrew M.

213

Energy barriers of the Ising model on percolation clusters : a numerical study  

E-Print Network (OSTI)

L- 667 Energy barriers of the Ising model on percolation clusters : a numerical study R. Rammal fini de spins d'Ising ferromagnétiques. Cette méthode est illustrée dans le cas des amas de percolation puissance bien connue dans les réseaux euclidiens. Certaines conséquences de ces résultats pour le modèle d'Ising

Paris-Sud XI, Université de

214

Numerical-Model Investigation of the Hydrothermal Regime of a Straight-Through Shallow Cooling Pond  

SciTech Connect

A mathematic model based on solution of hydrodynamics and heat-transfer equations by the finite-element method is constructed to predict the hydrothermal regime of a straight-through shallow cooling pond, which provides cooling circulating water to a repository of spent nuclear fuel. Numerical experiments made it possible to evaluate the influence exerted by wind conditions and flow rate of water in the river on the temperature of the circulating water.

Sokolov, A. S. [JSC 'VNIIG im. B. E. Vedeneeva' (Russian Federation)] [JSC 'VNIIG im. B. E. Vedeneeva' (Russian Federation)

2013-11-15T23:59:59.000Z

215

An Investigation into Satellite Drag Modeling Performance  

E-Print Network (OSTI)

parameters, but with so much variability, capturing the small scale changes the atmosphere undergoes is difficult. Many techniques have been developed to fine tune atmospheric models to include these variations. One such technique is dynamic calibration... ............................................................................. 49 2.3.1 Atmospheric Modeling Upgrade ..................................................... 50 2.3.1.1 NRLMSISE-2000 Modification ...................................................... 50 2.3.1.2 DCA Corrections Modification...

Mance, Stephen

2010-03-23T23:59:59.000Z

216

Appendix MASS: Performance Assessment Modeling Assumptions  

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

Rock Units MASS-12.2 Historical Context of the Salado Conceptual Model MASS-12.3 The Fracture Model MASS-12.4 Flow in the DRZ MASS-12.5 Actinide Transport in the Salado MASS-13.0...

217

Model Documents for an Energy Savings Performance Contract Project...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

to help you launch energy efficiency projects through Energy Savings Performance Contracting (ESPC). Read about how these documents were developed. The ESPC Model Documents...

218

Numerical modeling of dust particle configurations in a cylindrical radio-frequency plasma reactor  

Science Journals Connector (OSTI)

In the present work, first, plasma phase variables in a cylindrical radio-frequency (rf) plasma reactor are numerically solved using the local field approximation model. Then, equilibrium configurations of a few interacting (sub-)micron-sized dust particles are obtained by integrating the particles equations for their motion and charge, accounting for the various forces acting on each particle in a three-dimensional Lagrangian framework. Direct comparison of the results with experiment demonstrates excellent qualitative agreement. Based on the ion focus phenomenon, a physical model is formulated and proven successful in simulating the vertically aligned structures.

M. Davoudabadi and F. Mashayek

2007-11-30T23:59:59.000Z

219

Numerical and analytical modeling of heat transfer between fluid and fractured rocks  

E-Print Network (OSTI)

Modeling of heat transfer between fluid and fractured rocks is of particular importance for energy extraction analysis in EGS, and therefore represents a critical component of EGS design and performance evaluation. In ...

Li, Wei, S.M. Massachusetts Institute of Technology

2014-01-01T23:59:59.000Z

220

Modeling Windows in Energy Plus with Simple Performance Indices  

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

Modeling Windows in Energy Plus with Simple Performance Indices Modeling Windows in Energy Plus with Simple Performance Indices Title Modeling Windows in Energy Plus with Simple Performance Indices Publication Type Report LBNL Report Number LBNL-2804E Year of Publication 2009 Authors Arasteh, Dariush K., Christian Kohler, and Brent T. Griffith Date Published 10/2009 Call Number LBNL-2804E Abstract The paper describes the development of a model specification for performance monitoring systems for commercial buildings. The specification focuses on four key aspects of performance monitoring: performance metrics measurement system requirements data acquisition and archiving data visualization and reporting The aim is to assist building owners in specifying the extensions to their control systems that are required to provide building operators with the information needed to operate their buildings more efficiently and to provide automated diagnostic tools with the information required to detect and diagnose faults and problems that degrade energy performance.

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


221

The numerical calculation of single-diode solar-cell modelling parameters  

Science Journals Connector (OSTI)

Abstract The accurate simulation of a photovoltaic solar cell requires the precise determination of modelling parameters specific to the device under study. For the case of the single diode model, five parameters must be determined; Iph, I0, Rs, Rsh, and n. Generally speaking these values may be calculated either by analytical or numerical methods. Although analytical approaches are simple and fast to carry out, the assumptions and simplifications they introduce in order to deal with the non-linear characteristics of a solar cell may result in modelling inaccuracies. In this study a new approach is presented to calculate all five parameter values numerically minimising assumptions and simplifications. The method proposed is based on solving the single diode current–voltage equation expressed using the Lambert W-function at five experimentally obtained points along the current–voltage curve. To solve the system of non-linear equations, the multi-dimensional variant of the Newton–Raphson method is applied. All necessary first order partial differential equations are provided in closed form. Experimental validation of the proposed method revealed an improvement in modelling accuracy over one commonly used analytical approach. Furthermore, using TRNSYS software to simulate the annual energy output we show that modelling photovoltaic systems with small variations in solar cell parameters can result in non-trivial variations in annual energy output highlighting the importance of their calculation.

F. Ghani; G. Rosengarten; M. Duke; J.K. Carson

2014-01-01T23:59:59.000Z

222

On the formulation, parameter identification and numerical integration of the EMMI model :plasticity and isotropic damage.  

SciTech Connect

In this report we present the formulation of the physically-based Evolving Microstructural Model of Inelasticity (EMMI) . The specific version of the model treated here describes the plasticity and isotropic damage of metals as being currently applied to model the ductile failure process in structural components of the W80 program . The formulation of the EMMI constitutive equations is framed in the context of the large deformation kinematics of solids and the thermodynamics of internal state variables . This formulation is focused first on developing the plasticity equations in both the relaxed (unloaded) and current configurations. The equations in the current configuration, expressed in non-dimensional form, are used to devise the identification procedure for the plasticity parameters. The model is then extended to include a porosity-based isotropic damage state variable to describe the progressive deterioration of the strength and mechanical properties of metals induced by deformation . The numerical treatment of these coupled plasticity-damage constitutive equations is explained in detail. A number of examples are solved to validate the numerical implementation of the model.

Bammann, Douglas J.; Johnson, G. C. (University of California, Berkeley, CA); Marin, Esteban B.; Regueiro, Richard A. (University of Colorado, Boulder, CO)

2006-01-01T23:59:59.000Z

223

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

Science Journals Connector (OSTI)

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

Du Lipeng; Tian Ruifeng; Zhang Pengfei; Sun Zhongning

2011-01-01T23:59:59.000Z

224

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

Science Journals Connector (OSTI)

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

A. García-Gutiérrez; A.F. Hernández; J.I. Martínez; M. Ceceñas; R. Ovando; I. Canchola

2015-01-01T23:59:59.000Z

225

Performance Modeling and Access Methods for Temporal Database Management Systems  

E-Print Network (OSTI)

implementation issues. Database systems with temporal support maintain history data on line together with current. Performance Modeling and Access Methods for Temporal Database Management Systems TR86-018 August. #12;Performance Modeling and Access Methods for Temporal Database Management Systems by Ilsoo Ahn

North Carolina at Chapel Hill, University of

226

Performance Modeling of Shared Memory Programsof SharedMemory Programs  

E-Print Network (OSTI)

nus edu sg/~teoymURL: www.comp.nus.edu.sg/ teoym 7th Workshop on High Performance Computing UPM Analysis l i l d l­ Analytical Model · Summary 1 November 2011 47th Workshop on High Performance Computing November 2011 57th Workshop on High Performance Computing (invited talk) #12;R l t d W kRelated Work

Teo, Yong-Meng

227

Developing an Energy Performance Modeling Startup Kit  

SciTech Connect

In 2011, the NAHB Research Center began the first part of the multi-year effort by assessing the needs and motivations of residential remodelers regarding energy performance remodeling. The scope is multifaceted - all perspectives will be sought related to remodeling firms ranging in size from small-scale, sole proprietor to national. This will allow the Research Center to gain a deeper understanding of the remodeling and energy retrofit business and the needs of contractors when offering energy upgrade services. To determine the gaps and the motivation for energy performance remodeling, the NAHB Research Center conducted (1) an initial series of focus groups with remodelers at the 2011 International Builders' Show, (2) a second series of focus groups with remodelers at the NAHB Research Center in conjunction with the NAHB Spring Board meeting in DC, and (3) quantitative market research with remodelers based on the findings from the focus groups. The goal was threefold, to: Understand the current remodeling industry and the role of energy efficiency; Identify the gaps and barriers to adding energy efficiency into remodeling; and Quantify and prioritize the support needs of professional remodelers to increase sales and projects involving improving home energy efficiency. This report outlines all three of these tasks with remodelers.

Wood, A.

2012-10-01T23:59:59.000Z

228

Numerical modelling of sandstone uniaxial compression test using a mix-mode cohesive fracture model  

E-Print Network (OSTI)

A mix-mode cohesive fracture model considering tension, compression and shear material behaviour is presented, which has wide applications to geotechnical problems. The model considers both elastic and inelastic displacements. Inelastic displacement comprises fracture and plastic displacements. The norm of inelastic displacement is used to control the fracture behaviour. Meantime, a failure function describing the fracture strength is proposed. Using the internal programming FISH, the cohesive fracture model is programmed into a hybrid distinct element algorithm as encoded in Universal Distinct Element Code (UDEC). The model is verified through uniaxial tension and direct shear tests. The developed model is then applied to model the behaviour of a uniaxial compression test on Gosford sandstone. The modelling results indicate that the proposed cohesive fracture model is capable of simulating combined failure behaviour applicable to rock.

Gui, Yilin; Kodikara, Jayantha

2015-01-01T23:59:59.000Z

229

A Numerical Model For The Dynamics Of Pyroclastic Flows At Galeras Volcano,  

Open Energy Info (EERE)

For The Dynamics Of Pyroclastic Flows At Galeras Volcano, For The Dynamics Of Pyroclastic Flows At Galeras Volcano, Colombia Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Numerical Model For The Dynamics Of Pyroclastic Flows At Galeras Volcano, Colombia Details Activities (0) Areas (0) Regions (0) Abstract: This paper presents a two-dimensional model for dilute pyroclastic flow dynamics that uses the compressible Navier-Stokes equation coupled with the Diffusion-Convection equation to take into account sedimentation. The model is applied to one of the slopes of Galeras Volcano to show: (1) the temperature evolution with the time; (2) dynamic pressure change; and (3) particle concentration along the computer domain from the eruption to the impact with a topographic barrier located more than 16 km

230

Nanofluid \\{PCMs\\} for thermal energy storage: Latent heat reduction mechanisms and a numerical study of effective thermal storage performance  

Science Journals Connector (OSTI)

Abstract The latent heat of fusion of paraffin-based nanofluids has been examined to investigate the use of enhanced phase change materials (PCMs) for thermal energy storage (TES) applications. The nanofluid approach has often been exploited to enhance thermal conductivity of PCMs, but the effects of particle addition on other thermal properties affecting TES are relatively ignored. An experimental study of paraffin-based nanofluids containing various particle sizes of multi-walled carbon nanotubes has been conducted to investigate the effect of nanoparticles on latent heat of fusion. Results demonstrated that the magnitude of nanofluid latent heat reduction increases for smaller diameter particles in suspension. Three possible mechanisms – interfacial liquid layering, Brownian motion, and particle clustering – were examined to explain further reduction in latent heat, through the weakening of molecular bond structures. Although additional research is required to explore detailed mechanisms, experimental evidence suggests that interfacial liquid layering and Brownian motion cannot explain the degree of latent heat reduction observed. A finite element model is also presented as a method of quantifying nanofluid PCM energy storage performance. Thermal properties based on modified effective medium theory and an empirical relation for latent heat of fusion were applied as model parameters to determine energy stored and extracted over a given period of time. The model results show that while micro-scale particle inclusions exhibit some performance enhancement, nanoparticles in \\{PCMs\\} provide no significant improvement in TES performance. With smaller particles, the enhancement in thermal conductivity is not significant enough to overcome the reduction in latent heat of fusion, and less energy is stored over the PCM charge period. Therefore, the nanofluid approach may not be justifiable for energy storage applications. However, since the model parameters are dependent on the material properties of the system observed, storage performance may vary for differing nanofluid materials.

Aitor Zabalegui; Dhananjay Lokapur; Hohyun Lee

2014-01-01T23:59:59.000Z

231

The VOLNA code for the numerical modelling of tsunami waves: generation, propagation and inundation  

E-Print Network (OSTI)

A novel tool for tsunami wave modelling is presented. This tool has the potential of being used for operational purposes: indeed, the numerical VOLNA code is able to handle the complete life-cycle of a tsunami (generation, propagation and run-up along the coast). The algorithm works on unstructured triangular meshes and, thus, can be run in arbitrary complex domains. It is often the case since natural coasts tend to be of fractal shape [Sapoval et al, 2004]. This paper contains the detailed description of the finite volume scheme implemented in the code. We explain the numerical treatment of the wet/dry transition. This point is crucial for accurate run-up computation. Most existing tsunami codes use semi-empirical techniques at this stage, which are not always sufficient. The main reason is that people evacuation is decided on the base of inundation maps which are produced with this type of numerical tools. Finally we present several realistic test cases that partially validate our algorithm. Comparisons wit...

Dutykh, Denys; Dias, Frédéric

2010-01-01T23:59:59.000Z

232

Performance and Optimization of Network Building Evacuation Models  

E-Print Network (OSTI)

Performance and Optimization of Network Building Evacuation Models Andrea Weiss, Dr. Jim Mac/G/C/C queues, a simulation program was used to model two buildings on the Umass Amherst campus: Machmer Hall expedient paths are taken. Research Objectives · Create a realistic model of buildings with large

Mountziaris, T. J.

233

Mixture Preparation and Nitric Oxide Formation in a GDI Engine studied by Combined Laser Diagnostics and Numerical Modeling  

SciTech Connect

Through the combination of advanced imaging laser diagnostics with multi-dimensional computer models, a new understanding of the performance of direct-injection gasoline engines is pursuit. The work focuses on the fuel injection process, the breakup of the liquid into a fine spray and the mixing of the fuel with the in-cylinder gases. Non-intrusive laser diagnostics will be used to measure the spatial distribution of droplets and vaporized fuel with very high temporal resolution. These data along with temperature measurements will be used to validate a new spray breakup model for gasoline direct-injection. Experimental data on near wall fuel distributions will be used for comparison with a model that predicts the spray-wall interaction and the dynamics of the liquid film on the surface. Quantitative measurements of local nitric oxide concentrations inside the combustion chamber will provide a critical test for a numerical simulation of the nitric oxide formation process. This model is based on a modified flamelet approach and will be used to study the effects of exhaust gas recirculation.

Volker Sick; Dennis N. Assanis

2002-11-27T23:59:59.000Z

234

Assimilation of Satellite Cloud and Precipitation Observations in Numerical Weather Prediction Models: Introduction to the JAS Special Collection  

Science Journals Connector (OSTI)

To date, the assimilation of satellite measurements in numerical weather prediction (NWP) models has focused on the clear atmosphere. But satellite observations in the visible, infrared, and microwave provide a great deal of information on clouds ...

Ronald M. Errico; George Ohring; Fuzhong Weng; Peter Bauer; Brad Ferrier; Jean-François Mahfouf; Joe Turk

2007-11-01T23:59:59.000Z

235

A viscous vortex single-mode bubble evolution model of Rayleigh-Taylor instability and its numerical study  

Science Journals Connector (OSTI)

This paper has developed a viscous single-mode bubble evolution model of Rayleigh-Taylor instabilities (RTIs), which is an extension of the single-mode potential models of Jacobs and Rikanati. The viscous vortex model explained the viscous effects of its early stage of RTI development for low Atwood number flow. Furthermore, direct numerical simulations of RTI are studied with Navier-Stokes equations and a transport-diffusive equation. Agreement between the theoretical model and the numerical results shows that simulations of these instabilities is feasible using the mathematical miscible fluid model simulating RTI.

Xu Zhang; Jinhong Liu

2013-01-01T23:59:59.000Z

236

Numerical Weather Prediction (NWP) and hybrid ARMA/ANN model to predict global radiation  

E-Print Network (OSTI)

We propose in this paper an original technique to predict global radiation using a hybrid ARMA/ANN model and data issued from a numerical weather prediction model (ALADIN). We particularly look at the Multi-Layer Perceptron. After optimizing our architecture with ALADIN and endogenous data previously made stationary and using an innovative pre-input layer selection method, we combined it to an ARMA model from a rule based on the analysis of hourly data series. This model has been used to forecast the hourly global radiation for five places in Mediterranean area. Our technique outperforms classical models for all the places. The nRMSE for our hybrid model ANN/ARMA is 14.9% compared to 26.2% for the na\\"ive persistence predictor. Note that in the stand alone ANN case the nRMSE is 18.4%. Finally, in order to discuss the reliability of the forecaster outputs, a complementary study concerning the confidence interval of each prediction is proposed

Voyant, Cyril; Paoli, Christophe; Nivet, Marie Laure

2012-01-01T23:59:59.000Z

237

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

Science Journals Connector (OSTI)

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

Uwe Schnell

2001-01-01T23:59:59.000Z

238

Comment on "Time Step Sensitivity of Nonlinear Atmospheric Models: Numerical Convergence, Truncation Error Growth, and Ensemble Design" Teixeira et al. (2007)  

E-Print Network (OSTI)

Comment on "Time Step Sensitivity of Nonlinear Atmospheric Models: Numerical Convergence, Truncation Error Growth, and Ensemble Design" Teixeira et al.

Lun-Shin Yao; Dan Hughes

2007-04-26T23:59:59.000Z

239

Models Used to Assess the Performance of Photovoltaic Systems  

Energy.gov (U.S. Department of Energy (DOE))

This report documents the various photovoltaic (PV) performance models and software developed and utilized by researchers at Sandia National Laboratories (SNL) in support of the Photovoltaics and Grid Integration Department. In addition to PV performance models, hybrid system and battery storage models are discussed. A hybrid system using other distributed sources and energy storage can help reduce the variability inherent in PV generation, and due to the complexity of combining multiple generation sources and system loads, these models are invaluable for system design and optimization.

240

Terahertz imaging system performance model for concealed-weapon identification  

Science Journals Connector (OSTI)

The U.S. Army Night Vision and Electronic Sensors Directorate (NVESD) and the U.S. Army Research Laboratory have developed a terahertz (THz) -band imaging system performance model...

Murrill, Steven R; Jacobs, Eddie L; Moyer, Steven K; Halford, Carl E; Griffin, Steven T; De Lucia, Frank C; Petkie, Douglas T; Franck, Charmaine C

2008-01-01T23:59:59.000Z

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


241

Models used to assess the performance of photovoltaic systems.  

SciTech Connect

This report documents the various photovoltaic (PV) performance models and software developed and utilized by researchers at Sandia National Laboratories (SNL) in support of the Photovoltaics and Grid Integration Department. In addition to PV performance models, hybrid system and battery storage models are discussed. A hybrid system using other distributed sources and energy storage can help reduce the variability inherent in PV generation, and due to the complexity of combining multiple generation sources and system loads, these models are invaluable for system design and optimization. Energy storage plays an important role in reducing PV intermittency and battery storage models are used to understand the best configurations and technologies to store PV generated electricity. Other researcher's models used by SNL are discussed including some widely known models that incorporate algorithms developed at SNL. There are other models included in the discussion that are not used by or were not adopted from SNL research but may provide some benefit to researchers working on PV array performance, hybrid system models and energy storage. The paper is organized into three sections to describe the different software models as applied to photovoltaic performance, hybrid systems, and battery storage. For each model, there is a description which includes where to find the model, whether it is currently maintained and any references that may be available. Modeling improvements underway at SNL include quantifying the uncertainty of individual system components, the overall uncertainty in modeled vs. measured results and modeling large PV systems. SNL is also conducting research into the overall reliability of PV systems.

Stein, Joshua S.; Klise, Geoffrey T.

2009-12-01T23:59:59.000Z

242

Execution-Less Performance Modeling Roman Iakymchuk and Paolo Bientinesi  

E-Print Network (OSTI)

Execution-Less Performance Modeling Roman Iakymchuk and Paolo Bientinesi AICES, RWTH Aachen occurring in higher- level algorithms--like a matrix factorization--is then pre- dicted by combining a priori; the prediction of performance therefore reduces to the pre- diction of Execution time. Our

243

Modeling the Performance and Energy of Storage Arrays  

E-Print Network (OSTI)

, it is desirable that techniques provide their energy savings while minimizing their impact on performance. DespiteModeling the Performance and Energy of Storage Arrays Sankaran Sivathanu Georgia Institute techniques for power optimization in storage. Given an ar- bitrary trace of disk requests, we split

Liu, Ling

244

High Performance Computing Modeling Advances Accelerator Science for High Energy Physics  

SciTech Connect

The development and optimization of particle accelerators are essential for advancing our understanding of the properties of matter, energy, space and time. Particle accelerators are complex devices whose behavior involves many physical effects on multiple scales. Therefore, advanced computational tools utilizing high-performance computing (HPC) are essential for accurately modeling them. In the past decade, the DOE SciDAC program has produced such accelerator-modeling tools, which have beem employed to tackle some of the most difficult accelerator science problems. In this article we discuss the Synergia beam-dynamics framework and its applications to high-intensity particle accelerator physics. Synergia is an accelerator simulation package capable of handling the entire spectrum of beam dynamics simulations. We present the design principles, key physical and numerical models in Synergia and its performance on HPC platforms. Finally, we present the results of Synergia applications for the Fermilab proton source upgrade, known as the Proton Improvement Plan (PIP).

Amundson, James; Macridin, Alexandru; Spentzouris, Panagiotis

2014-04-29T23:59:59.000Z

245

Agriculture model development to improve performance of the Community Land  

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

Agriculture model development to improve performance of the Community Land Agriculture model development to improve performance of the Community Land Model April 3, 2013 The important relationships between climate change and agriculture are uncertain, particularly the feedbacks related to the carbon cycle. Nevertheless, vegetation models have not yet considered the full impacts of management practices and nitrogen feedbacks on the carbon cycle. We are working to meet this need. We have integrated three crop types (corn, soybean, and spring wheat) into the Community Land Model (CLM). In developing the agriculture version of CLM, we added plant processes related to management practices and nitrogen cycling. A manuscript documenting our changes to CLM has been accepted for publication in Geoscientific Model Development Discussions ("Modeling

246

Combined Modeling of Acceleration, Transport, and Hydrodynamic Response in Solar Flares. I. The Numerical Model  

Science Journals Connector (OSTI)

Acceleration and transport of high-energy particles and fluid dynamics of atmospheric plasma are interrelated aspects of solar flares, but for convenience and simplicity they were artificially separated in the past. We present here self-consistently combined Fokker-Planck modeling of particles and hydrodynamic simulation of flare plasma. Energetic electrons are modeled with the Stanford unified code of acceleration, transport, and radiation, while plasma is modeled with the Naval Research Laboratory flux tube code. We calculated the collisional heating rate directly from the particle transport code, which is more accurate than those in previous studies based on approximate analytical solutions. We repeated the simulation of Mariska et al. with an injection of power law, downward-beamed electrons using the new heating rate. For this case, a ~10% difference was found from their old result. We also used a more realistic spectrum of injected electrons provided by the stochastic acceleration model, which has a smooth transition from a quasi-thermal background at low energies to a nonthermal tail at high energies. The inclusion of low-energy electrons results in relatively more heating in the corona (versus chromosphere) and thus a larger downward heat conduction flux. The interplay of electron heating, conduction, and radiative loss leads to stronger chromospheric evaporation than obtained in previous studies, which had a deficit in low-energy electrons due to an arbitrarily assumed low-energy cutoff. The energy and spatial distributions of energetic electrons and bremsstrahlung photons bear signatures of the changing density distribution caused by chromospheric evaporation. In particular, the density jump at the evaporation front gives rise to enhanced emission, which, in principle, can be imaged by X-ray telescopes. This model can be applied to investigate a variety of high-energy processes in solar, space, and astrophysical plasmas.

Wei Liu; Vahé Petrosian; John T. Mariska

2009-01-01T23:59:59.000Z

247

COMBINED MODELING OF ACCELERATION, TRANSPORT, AND HYDRODYNAMIC RESPONSE IN SOLAR FLARES. I. THE NUMERICAL MODEL  

SciTech Connect

Acceleration and transport of high-energy particles and fluid dynamics of atmospheric plasma are interrelated aspects of solar flares, but for convenience and simplicity they were artificially separated in the past. We present here self-consistently combined Fokker-Planck modeling of particles and hydrodynamic simulation of flare plasma. Energetic electrons are modeled with the Stanford unified code of acceleration, transport, and radiation, while plasma is modeled with the Naval Research Laboratory flux tube code. We calculated the collisional heating rate directly from the particle transport code, which is more accurate than those in previous studies based on approximate analytical solutions. We repeated the simulation of Mariska et al. with an injection of power law, downward-beamed electrons using the new heating rate. For this case, a {approx}10% difference was found from their old result. We also used a more realistic spectrum of injected electrons provided by the stochastic acceleration model, which has a smooth transition from a quasi-thermal background at low energies to a nonthermal tail at high energies. The inclusion of low-energy electrons results in relatively more heating in the corona (versus chromosphere) and thus a larger downward heat conduction flux. The interplay of electron heating, conduction, and radiative loss leads to stronger chromospheric evaporation than obtained in previous studies, which had a deficit in low-energy electrons due to an arbitrarily assumed low-energy cutoff. The energy and spatial distributions of energetic electrons and bremsstrahlung photons bear signatures of the changing density distribution caused by chromospheric evaporation. In particular, the density jump at the evaporation front gives rise to enhanced emission, which, in principle, can be imaged by X-ray telescopes. This model can be applied to investigate a variety of high-energy processes in solar, space, and astrophysical plasmas.

Liu Wei [Stanford-Lockheed Institute for Space Research, 466 Via Ortega, Cypress Hall, Stanford, CA 94305-4085 (United States); Petrosian, Vahe [Department of Physics, Stanford University, Stanford, CA 94305-4060 (United States); Mariska, John T. [Naval Research Laboratory, Code 7673, Washington, DC 20375-5000 (United States)

2009-09-10T23:59:59.000Z

248

Using numerical models of bow shocks to investigate the circumstellar medium of massive stars  

E-Print Network (OSTI)

Many massive stars travel through the interstellar medium at supersonic speeds. As a result they form bow shocks at the interface between the stellar wind. We use numerical hydrodynamics to reproduce such bow shocks numerically, creating models that can be compared to observations. In this paper we discuss the influence of two physical phenomena, interstellar magnetic fields and the presence of interstellar dust grains on the observable shape of the bow shocks of massive stars. We find that the interstellar magnetic field, though too weak to restrict the general shape of the bow shock, reduces the size of the instabilities that would otherwise be observed in the bow shock of a red supergiant. The interstellar dust grains, due to their inertia can penetrate deep into the bow shock structure of a main sequence O-supergiant, crossing over from the ISM into the stellar wind. Therefore, the dust distribution may not always reflect the morphology of the gas. This is an important consideration for infrared observati...

van Marle, Allard Jan; Cox, Nick; Meliani, Zakaria

2014-01-01T23:59:59.000Z

249

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

SciTech Connect

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

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

2005-06-01T23:59:59.000Z

250

Comparison of Predictive Models for Photovoltaic Module Performance: Preprint  

SciTech Connect

This paper examines three models used to estimate the performance of photovoltaic (PV) modules when the irradiances and PV cell temperatures are known. The results presented here were obtained by comparing modeled and measured maximum power (Pm) for PV modules that rely on different technologies.

Marion, B.

2008-05-01T23:59:59.000Z

251

"Performance and Optimization of Building Evacuation Models" Andrea Weiss  

E-Print Network (OSTI)

"Performance and Optimization of Building Evacuation Models" Andrea Weiss Faculty Mentor: Dr. James in ensuring safety of individuals inside a building. In order to determine the most efficient paths, models that can be made when representing a building. By breaking the rooms and hallways into smaller sections

Mountziaris, T. J.

252

An Updated Numerical Model Of The Larderello-Travale Geothermal System,  

Open Energy Info (EERE)

Of The Larderello-Travale Geothermal System, Of The Larderello-Travale Geothermal System, Italy Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: An Updated Numerical Model Of The Larderello-Travale Geothermal System, Italy Details Activities (0) Areas (0) Regions (0) Abstract: Larderello-Travale is one of the few geothermal systems in the world that is characterized by a reservoir pressure much lower than hydrostatic. This is a consequence of its natural evolution from an initial liquid-dominated to the current steam-dominated system. Beneath a nearly impermeable cover, the geothermal reservoir consists of carbonate-anhydrite formations and, at greater depth, by metamorphic rocks. The shallow reservoir has temperatures in the range of 220-250°C, and pressures of about 20 bar at a depth of 1000 m, while the deep metamorphic reservoir has

253

Numerical determination of OPE coefficients in the 3D Ising model from off-critical correlators  

E-Print Network (OSTI)

We propose a general method for the numerical evaluation of OPE coefficients in three dimensional Conformal Field Theories based on the study of the conformal perturbation of two point functions in the vicinity of the critical point. We test our proposal in the three dimensional Ising Model, looking at the magnetic perturbation of the $$, $$ and $$ correlators from which we extract the values of $C^{\\sigma}_{\\sigma\\epsilon}=1.07(3)$ and $C^{\\epsilon}_{\\epsilon\\epsilon}=1.45(30)$. Our estimate for $C^{\\sigma}_{\\sigma\\epsilon}$ agrees with those recently obtained using conformal bootstrap methods, while $C^{\\epsilon}_{\\epsilon\\epsilon}$, as far as we know, is new and could be used to further constrain conformal bootstrap analyses of the 3d Ising universality class.

Caselle, M; Magnoli, N

2015-01-01T23:59:59.000Z

254

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

E-Print Network (OSTI)

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

Kerley, Gerald I

2013-01-01T23:59:59.000Z

255

Improving the assessment of wave energy resources by means of coupled wave-ocean numerical modeling  

Science Journals Connector (OSTI)

Abstract Sea waves energy represents a renewable and sustainable energy resource, that nevertheless needs to be further investigated to make it more cost-effective and economically appealing. A key step in the process of Wave Energy Converters (WEC) deployment is the energy resource assessment at a sea site either measured or obtained through numerical model analysis. In these kind of studies, some approximations are often introduced, especially in the early stages of the process, viz. waves are assumed propagating in deep waters without underneath ocean currents. These aspects are discussed and evaluated in the Adriatic Sea and its northern part (Gulf of Venice) using locally observed and modeled wave data. In particular, to account for a “state of the art” treatment of the Wave–Current Interaction (WCI) we have implemented the Simulating \\{WAves\\} Nearshore (SWAN) model and the Regional Ocean Modeling System (ROMS), fully coupled within the Coupled Ocean Atmosphere Wave Sediment Transport (COAWST) system. COAWST has been applied to a computational grid covering the whole Adriatic Sea and off-line nested to a high-resolution grid in the Gulf of Venice. A 15-year long wave data set collected at the oceanographic tower “Acqua Alta”, located approximately 15 km off the Venice coast, has also been analyzed with the dual purpose of providing a reference to the model estimates and to locally assess the wave energy resource. By using COAWST, we have quantified for the first time to our best knowledge the importance of the WCI effect on wave power estimation. This can vary up to 30% neglecting the current effect. Results also suggest the Gulf of Venice as a suitable testing site for WECs, since it is characterized by periods of calm (optimal for safe installation and maintenance) alternating with severe storms, whose wave energy potentials are comparable to those ordinarily encountered in the energy production sites.

Francesco Barbariol; Alvise Benetazzo; Sandro Carniel; Mauro Sclavo

2013-01-01T23:59:59.000Z

256

Numerical calculation of AC substation grounding systems buried in a vertical multilayered earth model by higher-order basis function  

Science Journals Connector (OSTI)

To study the accuracy of numerical simulations for an AC substation grounding problem embedded in a vertical multilayered earth model, this paper proposes a novel algorithm combining the rapidly convergent one-dimensional Galerkin's BEM with higher-order ... Keywords: Green's function, high-order basic function, vertical multilayered earth model

Zhong-Xin Li; Jian-Bin Fan; Yu Yin

2012-05-01T23:59:59.000Z

257

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

E-Print Network (OSTI)

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

Boyer, Edmond

258

Numerical modeling of mixed sediment resuspension, transport, and deposition during the March 1998 episodic events in southern Lake  

E-Print Network (OSTI)

Numerical modeling of mixed sediment resuspension, transport, and deposition during the March 1998 2006; published 17 February 2007. [1] A two-dimensional sediment transport model capable of simulating sediment resuspension of mixed (cohesive plus noncohesive) sediment is developed and applied

259

Size-velocity correlations in high order moment methods for polydisperse evaporating sprays: modelling and numerical issues  

E-Print Network (OSTI)

, such as internal combustion engine ([1, 2] and references therein), gas turbine [3] or rocket booster [4]. Those developed the Eulerian Multi-Size Moment model (EMSM) which tackles the modelling and the numerical aspects of the disperse phase. The full strategy is evaluated in 1D and 2D cases and shows the ability of the CSVM and its

Paris-Sud XI, Université de

260

Human performance modeling for system of systems analytics.  

SciTech Connect

A Laboratory-Directed Research and Development project was initiated in 2005 to investigate Human Performance Modeling in a System of Systems analytic environment. SAND2006-6569 and SAND2006-7911 document interim results from this effort; this report documents the final results. The problem is difficult because of the number of humans involved in a System of Systems environment and the generally poorly defined nature of the tasks that each human must perform. A two-pronged strategy was followed: one prong was to develop human models using a probability-based method similar to that first developed for relatively well-understood probability based performance modeling; another prong was to investigate more state-of-art human cognition models. The probability-based modeling resulted in a comprehensive addition of human-modeling capability to the existing SoSAT computer program. The cognitive modeling resulted in an increased understanding of what is necessary to incorporate cognition-based models to a System of Systems analytic environment.

Dixon, Kevin R.; Lawton, Craig R.; Basilico, Justin Derrick; Longsine, Dennis E. (INTERA, Inc., Austin, TX); Forsythe, James Chris; Gauthier, John Henry; Le, Hai D.

2008-10-01T23:59:59.000Z

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


261

Human performance modeling for system of systems analytics :soldier fatigue.  

SciTech Connect

The military has identified Human Performance Modeling (HPM) as a significant requirement and challenge of future systems modeling and analysis initiatives as can be seen in the Department of Defense's (DoD) Defense Modeling and Simulation Office's (DMSO) Master Plan (DoD 5000.59-P 1995). To this goal, the military is currently spending millions of dollars on programs devoted to HPM in various military contexts. Examples include the Human Performance Modeling Integration (HPMI) program within the Air Force Research Laboratory, which focuses on integrating HPMs with constructive models of systems (e.g. cockpit simulations) and the Navy's Human Performance Center (HPC) established in September 2003. Nearly all of these initiatives focus on the interface between humans and a single system. This is insufficient in the era of highly complex network centric SoS. This report presents research and development in the area of HPM in a system-of-systems (SoS). Specifically, this report addresses modeling soldier fatigue and the potential impacts soldier fatigue can have on SoS performance.

Lawton, Craig R.; Campbell, James E.; Miller, Dwight Peter

2005-10-01T23:59:59.000Z

262

Performance Modeling for Exascale Autotuning: An Integrated Approach |  

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

Performance Modeling for Exascale Autotuning: An Integrated Approach Performance Modeling for Exascale Autotuning: An Integrated Approach Title Performance Modeling for Exascale Autotuning: An Integrated Approach Publication Type Miscellaneous Year of Publication 2013 Authors Balaprakash, P, Wild, SM, Hovland, PD Other Numbers ANL/MCS-P5000-0813 Abstract The usual suspects - shrinking integrated circuit feature sizes, heterogeneous nodes with many-core processors, deep memory hierarchies, an ever-present power wall, energy efficiency demands, and resiliency concerns - make exascale application and system co-design a daunting, complex task. Providing effective model-driven prediction and optimization capabilities at runtime and a software stack that includes model-informed autotuning are key to mitigating this complexity. We define autotuning for application-system co-design as a systematic process of navigating the space defined by other software and hardware parameters that affect the performance metrics of the application and the system. Autotuning should orchestrate hardware and software-provided knobs to reduce execution time, power draw, energy consumption, and other constituent features, such as memory footprints. Current autotuning approaches, however, are unlikely to be successful for application-system co-design at exascale: the number of parameters exposed at the hardware and software levels will be large, drastically increasing the decision space; rigorous approaches to optimizing multiple conflicting objectives simultaneously are absent; and there is a lack of multiple-metric performance models. Significant research is required to develop an integrated modeling, machine learning, and search approach in order to provide model-driven prediction and optimization capabilities at runtime.

263

Unified Performance and Power Modeling of Scientific Workloads  

SciTech Connect

It is expected that scientific applications executing on future large-scale HPC must be optimized not only in terms of performance, but also in terms of power consumption. As power and energy become increasingly constrained resources, researchers and developers must have access to tools that will allow for accurate prediction of both performance and power consumption. Reasoning about performance and power consumption in concert will be critical for achieving maximum utilization of limited resources on future HPC systems. To this end, we present a unified performance and power model for the Nek-Bone mini-application developed as part of the DOE's CESAR Exascale Co-Design Center. Our models consider the impact of computation, point-to-point communication, and collective communication

Song, Shuaiwen; Barker, Kevin J.; Kerbyson, Darren J.

2013-11-17T23:59:59.000Z

264

Coastal numerical modelling of tides: Sensitivity to domain size and remotely generated internal tide  

Science Journals Connector (OSTI)

The propagation of remotely generated superinertial internal tides constitutes a difficulty for the modelling of regional ocean tidal variability which we illustrate in several ways. First, the M2 tidal solution inside a control region located along the Southern California Bight coastline is monitored while the extent of the numerical domain is increased (up to 512 × 512  km). While the amplitude and phase of sea level averaged over the region is quasi-insensitive to domain size, a steady increase of kinetic energy, predominantly baroclinic, is observed with increasing domain size. The increasing flux of energy into the control region suggests that this trend is explained by the growing contribution from remote generation sites of internal tide which can propagate up to the control region. Increasing viscosities confirms this interpretation by lowering baroclinic energy levels and limiting their rate of increase with domain size. Doubling the grid spacing allows consideration of numerical domains 2 times larger. While the coarse grid has lower energy levels than the finer grid, the rate of energy increase with domain size appears to be slowing for the largest domain of the coarse grid simulations. Forcing the smallest domain with depth-varying tidal boundary conditions from the simulation in the largest domain produces energy levels inside the control region comparable to those in the control region for the largest domain, thereby confirming the feasibility of a nested approach. In contrast, simulations forced with a subinertial tidal constituent (K1) show that when the propagation of internal tide is limited, the control region kinetic energy is mostly barotropic and the magnitudes of variations of the kinetic energy with domain size are reduced.

Aurelien L. Ponte; Bruce D. Cornuelle

2013-01-01T23:59:59.000Z

265

Numerical modeling of air?to?sea transmission of light aircraft noise  

Science Journals Connector (OSTI)

Recent experiments at SIO have shown that the acoustic signature of a light aircraft can be detected by sensors in the water column as well as buried in the underlying sediment and a method for extracting the sound speed and attenuation from this Doppler shifted signal has been proposed. To test the accuracy of this geoacoustic inversion technique a numerical model of the air?water?sediment acoustic propagation including the effects of a high?speed airborne source has been developed based on the spectral method. Simulated acoustic data have been generated representing an aircraft flying over a microphone in the atmosphere a vertical line array in the ocean and a hydrophone buried 1?m deep in the sediment. The results of the geoacoustic inversion for sound speed and attenuation are compared to the known input parameter values of the model giving a sense of the relative errors that may be expected when applying the technique to experimental data. [Work supported by ONR.

2003-01-01T23:59:59.000Z

266

Numerical Modeling of Geomechanical Processes Related to CO{sub 2} Injection within Generic Reservoirs  

SciTech Connect

In this project generic anticline structures have been used for numerical modeling analyses to study the influence of geometrical parameters, fluid flow boundary conditions, in situ stress regime and inter-bedding friction coefficient on geomechanical risks such as fracture reactivation and fracture generation. The resulting stress states for these structures are also used to determine safe drilling directions and a methodology for wellbore trajection optimization is developed that is applicable for non-Andersonian stress states. The results of the fluid flow simulation show that the type of fluid flow boundary condition is of utmost importance and has significant impact on all injection related parameters. It is recommended that further research is conducted to establish a method to quantify the fluid flow boundary conditions for injection applications. The results of the geomechanical simulation show that in situ stress regime is a crucial, if not the most important, factor determining geomechanical risks. For extension and strike slip stress regimes anticline structures should be favored over horizontally layered basin as they feature higher ?P{sub c} magnitudes. If sedimentary basins are tectonically relaxed and their state of stress is characterized by the uni-axial strain model the basin is in exact frictional equilibrium and fluids should not be injected. The results also show that low inter bedding friction coefficients effectively decouple layers resulting in lower ?P{sub c} magnitudes, especially for the compressional stress regime.

Eckert, Andreas

2013-05-31T23:59:59.000Z

267

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

Science Journals Connector (OSTI)

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

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

2012-01-01T23:59:59.000Z

268

Three-dimensional numerical modeling of thermohaline and wind-driven circulations in the Persian Gulf  

Science Journals Connector (OSTI)

The Persian Gulf circulation is investigated with respect to the relevant forcing mechanism including wind stress and thermohaline surface fluxes by using a three-dimensional numerical hydrodynamic model. The model results show a correlation between the strength of the bottom layer outflow of the Persian Gulf and that of the Indian Ocean Surface Water (IOSW) inflow into the Gulf. The inflow of IOSW into the Gulf attain maximum values in May–June in conjunction with peak bottom outflow through the Hormuz Strait. The results of sensitivity experiment indicate that circulation is dominated by thermohaline flows at almost all parts of the Gulf. The heat fluxes play an essential role on the general circulation of the Persian Gulf. In spring and summer, the wind stress generates southeast-flowing surface currents of magnitude about 5 cm/s along the Saudi Arabia and Iranian coasts on the northern Gulf. In winter and autumn, due to weak static stability, the wind produces mesoscale eddies in most parts of the Gulf. In winter and spring the wind stress acts to reinforce the thermohaline circulation of deep outflow. Conversely, in summer and autumn the wind forcing acts in opposition to the thermohaline forcing and causes a bottom inflow from Oman Sea into the Gulf.

F. Hosseinibalam; S. Hassanzadeh; A. Rezaei-Latifi

2011-01-01T23:59:59.000Z

269

Theoretical and Numerical Analysis of a Class of Semi-Implicit Semi-Lagrangian Schemes Potentially Applicable to Atmospheric Models  

Science Journals Connector (OSTI)

In this paper, theoretical and numerical analyses of the properties of some complex semi-Lagrangian methods are performed to deal with the issues of the instability associated with the treatment of the nonlinear part of the forcing term. A class ...

Abdelaziz Beljadid; Abdolmajid Mohammadian; Martin Charron; Claude Girard

2014-12-01T23:59:59.000Z

270

Personal Computer-Based Model for Cool Storage Performance Simulation  

E-Print Network (OSTI)

PERSONAL COMPUTER-BASED MODEL FOR COOL STORAGE PERFORMANCE SIMULATION Leszek M. Kasprowicz, Jerold W. Jones, and James Hitzfelder The University of Texas at Austin ust tin, ABSTRACT A personal computer based hourly simulation model... can be achieved by applying cool storage systems which use stored energy for air-conditioning purposes during peak periods. Customers benefit from cool storage in two ways. First, demand charges are reduced since customers with sufficient thermal...

Kasprowicz, L. M.; Jones, J. W.; Hitzfelder, J.

1990-01-01T23:59:59.000Z

271

PERFORMANCE MODEL FOR MULTIBLADED WATER-PUMPING WIND-MILLS  

Science Journals Connector (OSTI)

ABSTRACT The steady and the dynamic equilibrium of a multibladed water-pumping wind-mill has been studied under the assumption of a simple model. Good agreement has been found between theoretical and experimental results. KEYWORDS Wind energy; water-pumping wind-mills; wind-mill design; wind-mill test; performance optimization.

R. Pallabazzer

1986-01-01T23:59:59.000Z

272

Cost and Performance Assumptions for Modeling Electricity Generation Technologies  

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

Cost and Performance Cost and Performance Assumptions for Modeling Electricity Generation Technologies Rick Tidball, Joel Bluestein, Nick Rodriguez, and Stu Knoke ICF International Fairfax, Virginia Subcontract Report NREL/SR-6A20-48595 November 2010 NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency & Renewable Energy, operated by the Alliance for Sustainable Energy, LLC. National Renewable Energy Laboratory 1617 Cole Boulevard Golden, Colorado 80401 303-275-3000 * www.nrel.gov Contract No. DE-AC36-08GO28308 Cost and Performance Assumptions for Modeling Electricity Generation Technologies Rick Tidball, Joel Bluestein, Nick Rodriguez, and Stu Knoke ICF International Fairfax, Virginia NREL Technical Monitor: Jordan Macknick

273

Summary Results for Brine Migration Modeling Performed by LANL LBNL and SNL for the UFD Program  

SciTech Connect

This report summarizes laboratory and field observations and numerical modeling related to coupled processes involving brine and vapor migration in geologic salt, focusing on recent developments and studies conducted at Sandia, Los Alamos, and Berkeley National Laboratories. Interest into the disposal of heat-generating waste in salt has led to interest into water distribution and migration in both run-of-mine crushed and intact geologic salt. Ideally a fully coupled thermal-hydraulic-mechanical-chemical simulation is performed using numerical models with validated constitutive models and parameters. When mechanical coupling is not available, mechanical effects are prescribed in hydraulic models as source, boundary, or initial conditions. This report presents material associated with developing appropriate initial conditions for a non-mechanical hydrologic simulation of brine migration in salt. Due to the strong coupling between the mechanical and hydrologic problems, the initial saturation will be low for the excavation disturbed zone surrounding the excavation. Although most of the material in this report is not new, the author hopes it is presented in a format making it useful to other salt researchers.

Kuhlman, Kristopher L.

2014-09-01T23:59:59.000Z

274

Numerical modeling of two-phase behavior in the PEFC gas diffusion layer  

SciTech Connect

A critical performance limitation in the polymer electrolye fuel cell (PEFC) is attributed to the mass transport loss originating from suboptimal liquid water transport and flooding phenomena. Liquid water can block the porous pathways in the fibrous gas diffusion layer (GDL) and the catalyst layer (CL), thus hindering oxygen transport from the flow field to the electrochemically actives sites in the catalyst layer. In this paper, the study of the two phase behavior and the durability implications due to the wetting characteristics in the carbon paper GDL are presented using a pore-scale modeling framework.

Mukherjee, Partha Pa223876 [Los Alamos National Laboratory; Kang, Qinjun [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory; Borup, Rod L [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

275

Numerical Modeling of the Stability of Face-Centered Cubic Metals with High Vacancy Concentration  

SciTech Connect

The objective of this research is to assess the possibility of forming an atomically porous structure in a low-density metal, e.g., Al with vacancies up to 0.20/lattice site; and to examine the effects of hydrogen and vacancy concentration on the stability of an atomically porous structure that has been experimentally produced in nickel. The approach involves numerical modeling using the Embedded-Atom Method (EAM). High vacancy concentrations cause the Al lattice to disorder at 300K. In contrast, Ni retains the face-centered-cubic structure at 300K for vacancy concentrations up to 0.15 Vac/lattice site. Unexpectedly, the lattice with 0.15 Vac/lattice site is more stable than the lattice with 0.10 or 0.20 Vac/lattice site. The Ni systems with 0.10 and 0.15 Vac/lattice site exhibit domains consisting of uniform lattice rotations. The Ni lattice with 0.15 Vac/lattice site is more stable with an initial distribution of random vacancies compared to ordered vacancies. The equilibrium lattice structures of Ni a d Al containing vacancies and H are less ordered to structures with vacancies only at 300K.

Brian P. Somerday; M. I. Baskes

1998-12-01T23:59:59.000Z

276

Reference Manual for the System Advisor Model's Wind Power Performance Model  

SciTech Connect

This manual describes the National Renewable Energy Laboratory's System Advisor Model (SAM) wind power performance model. The model calculates the hourly electrical output of a single wind turbine or of a wind farm. The wind power performance model requires information about the wind resource, wind turbine specifications, wind farm layout (if applicable), and costs. In SAM, the performance model can be coupled to one of the financial models to calculate economic metrics for residential, commercial, or utility-scale wind projects. This manual describes the algorithms used by the wind power performance model, which is available in the SAM user interface and as part of the SAM Simulation Core (SSC) library, and is intended to supplement the user documentation that comes with the software.

Freeman, J.; Jorgenson, J.; Gilman, P.; Ferguson, T.

2014-08-01T23:59:59.000Z

277

Maintenance personnel performance simulation (MAPPS) model: overview and evaluation efforts  

SciTech Connect

The development of the MAPPS model has been completed and the model is currently undergoing evaluation. These efforts are addressing a number of identified issues concerning practicality, acceptability, usefulness, and validity. Preliminary analysis of the evaluation data that has been collected indicates that MAPPS will provide comprehensive and reliable data for PRA purposes and for a number of other applications. The MAPPS computer simulation model provides the user with a sophisticated tool for gaining insights into tasks performed by NPP maintenance personnel. Its wide variety of input parameters and output data makes it extremely flexible for application to a number of diverse applications. With the demonstration of favorable model evaluation results, the MAPPS model will represent a valuable source of NPP maintainer reliability data and provide PRA studies with a source of data on maintainers that has previously not existed.

Knee, H.E.; Haas, P.M.; Siegel, A.I.; Bartter, W.D.; Wolf, J.J.; Ryan, T.G.

1984-01-01T23:59:59.000Z

278

Numerical modeling of deep groundwater flow and heat transport in the Williston Basin  

SciTech Connect

A numerical modeling approach has been used to evaluate quantitatively the effects of fluid flow on contemporary heat flow in an intracratonic basin. The authors have selected the Williston basin for this hydrodynamic study because of the opportunity it presents to assess the relation of deep groundwater flow to basin geothermics and the associated features of diagenesis and petroleum accumulation. The finite element method is used to solve the coupled equations of fluid flow and heat transport in two-dimensional sections of the basin. Both the fluid- and heat-flow regime are assumed to be at steady state, and the fluid flow is driven primarily by the water-table relief which is taken to be a subdued replica of land-surface topography. Buoyancy forces may also affect flow through fluid density gradients created by temperature and salinity effects. Three southwest-northwest oriented sections across the basin were modeled using available and estimated parameter data. The predicted flow patterns are most strongly affected by the topography, but the Devonian salt unit and Cretaceous shale unit exert some control. Cross-formational flow is especially important near the downdip, solution edge of the salt beds. Flow rates rarely exceed 0.5 m/year in the deep-central part of the basin, yet there does exist a marked effect on heat flow, albeit subdued by the blanket effect of the low-permeability Cretaceous shales. The regional effect of the topography-driven flow system is reflected in present-day salinity patterns and heat-flow data.

Garven, G.; Vigrass, L.

1985-01-01T23:59:59.000Z

279

A New Model to Simulate Energy Performance of VRF Systems  

SciTech Connect

This paper presents a new model to simulate energy performance of variable refrigerant flow (VRF) systems in heat pump operation mode (either cooling or heating is provided but not simultaneously). The main improvement of the new model is the introduction of the evaporating and condensing temperature in the indoor and outdoor unit capacity modifier functions. The independent variables in the capacity modifier functions of the existing VRF model in EnergyPlus are mainly room wet-bulb temperature and outdoor dry-bulb temperature in cooling mode and room dry-bulb temperature and outdoor wet-bulb temperature in heating mode. The new approach allows compliance with different specifications of each indoor unit so that the modeling accuracy is improved. The new VRF model was implemented in a custom version of EnergyPlus 7.2. This paper first describes the algorithm for the new VRF model, which is then used to simulate the energy performance of a VRF system in a Prototype House in California that complies with the requirements of Title 24 ? the California Building Energy Efficiency Standards. The VRF system performance is then compared with three other types of HVAC systems: the Title 24-2005 Baseline system, the traditional High Efficiency system, and the EnergyStar Heat Pump system in three typical California climates: Sunnyvale, Pasadena and Fresno. Calculated energy savings from the VRF systems are significant. The HVAC site energy savings range from 51 to 85percent, while the TDV (Time Dependent Valuation) energy savings range from 31 to 66percent compared to the Title 24 Baseline Systems across the three climates. The largest energy savings are in Fresno climate followed by Sunnyvale and Pasadena. The paper discusses various characteristics of the VRF systems contributing to the energy savings. It should be noted that these savings are calculated using the Title 24 prototype House D under standard operating conditions. Actual performance of the VRF systems for real houses under real operating conditions will vary.

Hong, Tianzhen; Pang, Xiufeng; Schetrit, Oren; Wang, Liping; Kasahara, Shinichi; Yura, Yoshinori; Hinokuma, Ryohei

2014-03-30T23:59:59.000Z

280

Wind assessment in complex terrain with the numeric model Aiolos implementation of the influence of roughness changes and stability  

E-Print Network (OSTI)

Wind assessment in complex terrain with the numeric model Aiolos ­ implementation of the influence of roughness changes and stability Ulrich Focken, Detlef Heinemann, Hans-Peter Waldl Department of Energy (EWA) gives good results for the wind potential estimation in flat areas. But besides many

Heinemann, Detlev

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


281

Numerical modelling of erosion processes in the Himalayas of Nepal: effects of spatial variations of rock strength and precipitation  

E-Print Network (OSTI)

Numerical modelling of erosion processes in the Himalayas of Nepal: effects of spatial variations of the morphology of mountain belts. Here we investigate the modalities of defor- mation in Central Nepal on a c that the pattern of uplift in Nepal is mainly dependent on both erodability and fault geometry, rather than

Demouchy, Sylvie

282

Thermodynamic Modeling and Numerical Simulation of Single-Shaft Microturbine Performance  

E-Print Network (OSTI)

A combined production system based on microturbine holds the promise of increasing energy utilization efficiency and improving environmental quality due to its many attractive merits as a distributed energy source technology. To analyze and evaluate...

Hao, X.; Zhang, G.; Zhou, J.; Chen, Y.

2006-01-01T23:59:59.000Z

283

Numerical modelling and experimental studies of thermal behaviour of building integrated thermal energy storage unit in a form of a ceiling panel  

Science Journals Connector (OSTI)

AbstractObjective The paper presents a new concept of building integrated thermal energy storage unit and novel mathematical and numerical models of its operation. This building element is made of gypsum based composite with microencapsulated PCM. The proposed heat storage unit has a form of a ceiling panel with internal channels and is, by assumption, incorporated in a ventilation system. Its task is to reduce daily variations of ambient air temperature through the absorption (and subsequent release) of heat in PCM, without additional consumption of energy. Methods The operation of the ceiling panel was investigated experimentally on a special set-up equipped with temperature sensors, air flow meter and air temperature control system. Mathematical and numerical models of heat transfer and fluid flow in the panel account for air flow in the panel as well as real thermal properties of the PCM composite, i.e.: thermal conductivity variation with temperature and hysteresis of enthalpy vs. temperature curves for heating and cooling. Proposed novel numerical simulator consists of two strongly coupled sub models: the first one – 1D – which deals with air flowing through the U-shaped channel and the second one – 3D – which deals with heat transfer in the body of the panel. Results Spatial and temporal air temperature variations, measured on the experimental set-up, were used to validate numerical model as well as to get knowledge of thermal performance of the panel operating in different conditions. Conclusion Preliminary results of experimental tests confirmed the ability of the proposed heat storage unit to effectively control the air temperature inside the building. However, detailed measurement of the temperature of PCM composite have shown some disadvantages of the panel used in the study, e.g. thickness of the walls and distribution of PCM should be optimized. This can be achieved with the aid of the numerical simulator developed in this research. Practical implications The proposed ceiling panel, optimised from the point of view of thermal performance in a given environmental conditions, can be used as a part of ventilation systems in residential and office buildings.

Maciej Jaworski; Piotr ?apka; Piotr Furma?ski

2014-01-01T23:59:59.000Z

284

A depth-averaged debris-flow model that includes the effects of evolving dilatancy. II. Numerical predictions and experimental tests  

Science Journals Connector (OSTI)

...Numerical predictions and experimental tests David L. George Richard M. Iverson e-mail...software package we call D-Claw. As tests of D-Claw, we compare model output with...our numerical solution technique, and tests of numerical predictions against experimental...

2014-01-01T23:59:59.000Z

285

A model for the transient performance simulation of solar cavity receivers  

Science Journals Connector (OSTI)

Abstract In this paper, a detailed model for the transient simulation of solar cavity receivers for concentrating solar power plants is presented. The proposed model aims to consider all the major phenomena influencing the performance of a cavity receiver, including radiation, convection and conduction heat transfer mechanisms. For the radiation heat exchange within the cavity, the radiosity method is implemented, where the view factor calculation for all the active and passive surfaces is performed by a ray tracing algorithm programmed in a free software environment for statistical computing, namely R. A one-dimensional modeling approach is used for the tubes constituting the receiver active panels, through which the heat transfer fluid (HTF) is pumped. The governing partial differential equations are solved numerically by applying the finite volume method. Convective heat losses are modeled through different correlations for natural and forced convection heat losses from the specific literature. Once the thermal behavior has been characterized, the geometry of the model is later fixed to check the consistency of the model and to study its dynamic characteristics. A specific 51.6 MWth, PS10 like receiver is used in this paper, although the implemented model has the flexibility to allow a variable number of panels and geometric configurations. At last, an adaptive neural controller, designed and trained offline, controls the outlet temperature of the molten salts to the desired operating value. Results for transient simulations are shown in the paper, demonstrating the plausibility of the estimations obtained with the developed model. The proposed model has been implemented in the Modelica language and based on the Modelica Standard Library (MSL) modeling approach.

Javier Samanes; Javier Garcia-Barberena

2014-01-01T23:59:59.000Z

286

EnKF Assimilation of High-Resolution, Mobile Doppler Radar Data of the 4 May 2007 Greensburg, Kansas, Supercell into a Numerical Cloud Model  

E-Print Network (OSTI)

Kalman filter (EnKF) technique into a non- hydrostatic, compressible numerical weather prediction model weather prediction (NWP) models to improve under- standing of convective storm dynamics is now a fairly, Kansas, Supercell into a Numerical Cloud Model ROBIN L. TANAMACHI,*,1,# LOUIS J. WICKER,@ DAVID C. DOWELL

Xue, Ming

287

Proceedings of the Workshop on Numerical Modeling of Thermohydrological Flow in Fractured Rock Masses, Feb. 19-20, 1980, Berkeley, CA  

E-Print Network (OSTI)

Mathematical modeling of thermal energy storage in aquifers:presented at the Thermal Energy storage in aquifers1979; Aquifer thermal energy storage—a numerical simulation

Witherspoon, P.A.

2010-01-01T23:59:59.000Z

288

Numerical Experiments on Soft X-ray Emission Optimization of Nitrogen Plasma in 3 kJ Plasma Focus SY-1 Using Modified Lee Model  

Science Journals Connector (OSTI)

The X-ray emission properties of nitrogen plasmas are numerically investigated using corona plasma equilibrium model. The X-ray emission intensities... ? , Ly ?

M. Akel; Sh. Al-Hawat; S. Lee

2009-12-01T23:59:59.000Z

289

Numerical modeling of combustion processes and pollutant formations in direct-injection diesel engines  

Science Journals Connector (OSTI)

The Representative Interactive Flamelet (RIF) concept has been applied to numerically simulate the combustion processes and pollutant formation in the direct injection...X formation including thermal NO path, pro...

Seong-Ku Kim; Joon Kyu Lee; Yong-Mo Kim; Jae-Hyun Ahn

2002-07-01T23:59:59.000Z

290

A numerical model of non-equilibrium thermal plasmas. I. Transport properties  

SciTech Connect

A self-consistent and complete numerical model for investigating the fundamental processes in a non-equilibrium thermal plasma system consists of the governing equations and the corresponding physical properties of the plasmas. In this paper, a new kinetic theory of the transport properties of two-temperature (2-T) plasmas, based on the solution of the Boltzmann equation using a modified Chapman-Enskog method, is presented. This work is motivated by the large discrepancies between the theories for the calculation of the transport properties of 2-T plasmas proposed by different authors in previous publications. In the present paper, the coupling between electrons and heavy species is taken into account, but reasonable simplifications are adopted, based on the physical fact that m{sub e}/m{sub h} Much-Less-Than 1, where m{sub e} and m{sub h} are, respectively, the masses of electrons and heavy species. A new set of formulas for the transport coefficients of 2-T plasmas is obtained. The new theory has important physical and practical advantages over previous approaches. In particular, the diffusion coefficients are complete and satisfy the mass conversation law due to the consideration of the coupling between electrons and heavy species. Moreover, this essential requirement is satisfied without increasing the complexity of the transport coefficient formulas. Expressions for the 2-T combined diffusion coefficients are obtained. The expressions for the transport coefficients can be reduced to the corresponding well-established expressions for plasmas in local thermodynamic equilibrium for the case in which the electron and heavy-species temperatures are equal.

Zhang XiaoNing; Xia WeiDong [Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Hefei, Anhui Province 230026 (China); Li HePing [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Murphy, Anthony B. [CSIRO Materials Science and Engineering, PO Box 218, Lindfield NSW 2070 (Australia)

2013-03-15T23:59:59.000Z

291

A numerical model of convective heat transfer in a three dimensional channel with baffles  

E-Print Network (OSTI)

to minimize the effects of the temperature. Chandrupatla and Sastri (1977) used a finite difference method to study laminar heat transfer and fluid flow for Non-Newtonian fluids. In the limiting case of Newtonian fluids their results showed good agreement... and Sastri (1977) for developing laminar flow in a rectangular smooth channel. Figure 4. 1 shows the numerically predicted centerline axial velocity compared with the experimental data of Goldstein and Kreid (1967). The agreement between the numerical...

Lopez Buso, Jorge Ricardo

2012-06-07T23:59:59.000Z

292

Numerical modeling of the transient behavior of a thermoelectric Electromagnetic Self-Induced Pump  

E-Print Network (OSTI)

. IMPROVED PUMP MODELS Momentum model theory Transient thermoelectric model theory CHAPTER IV MODELING METHODS AND RESULTS Lumped parameter model Hydraulic model Page ln tv v11 v111 14 18 21 24 29 29 . " 41 41 43 Thermoelectric model Full... " " " " " 17 Magnetic core structure 20 Momentum model component assembly illustration 32 10 Illustration of the effects that act on the thermoelectric elements " """" 37 12 Lumped parameter model flow chart Hydraulic model flow chart 42 44 13 Flow...

Djordjevic, Vladimir

2012-06-07T23:59:59.000Z

293

Toward a high performance distributed memory climate model  

SciTech Connect

As part of a long range plan to develop a comprehensive climate systems modeling capability, the authors have taken the Atmospheric General Circulation Model originally developed by Arakawa and collaborators at UCLA and have recast it in a portable, parallel form. The code uses an explicit time-advance procedure on a staggered three-dimensional Eulerian mesh. The authors have implemented a two-dimensional latitude/longitude domain decomposition message passing strategy. Both dynamic memory management and interprocessor communication are handled with macro constructs that are preprocessed prior to compilation. The code can be moved about a variety of platforms, including massively parallel processors, workstation clusters, and vector processors, with a mere change of three parameters. Performance on the various platforms as well as issues associated with coupling different models for major components of the climate system are discussed.

Wehner, M.F.; Ambrosiano, J.J.; Brown, J.C.; Dannevik, W.P.; Eltgroth, P.G.; Mirin, A.A. [Lawrence Livermore National Lab., CA (United States); Farrara, J.D.; Ma, C.C.; Mechoso, C.R.; Spahr, J.A. [Univ. of California, Los Angeles, CA (US). Dept. of Atmospheric Sciences

1993-02-15T23:59:59.000Z

294

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

Science Journals Connector (OSTI)

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

Sheng Chen; Jonas Tölke; Manfred Krafczyk

2009-07-14T23:59:59.000Z

295

Modeling Photovoltaic and Concentrating Solar Power Trough Performance, Cost, and Financing with Solar Advisor Model  

SciTech Connect

A comprehensive solar technology systems analysis model, the Solar Advisor Model (SAM), has been developed to support the federal R&D community and the solar industry by staff at the National Renewable Energy Laboratory (NREL) and Sandia National Laboratory. This model is able to model the finances, incentives, and performance of flat-plate photovoltaic (PV), concentrating PV, and concentrating solar power (specifically, parabolic troughs). The primary function of the model is to allow users to investigate the impact of variations in performance, cost, and financial parameters to better understand their impact on key figures of merit. Figures of merit related to the cost and performance of these systems include, but aren't limited to, system output, system efficiencies, levelized cost of energy, return on investment, and system capital and O&M costs. SAM allows users to do complex system modeling with an intuitive graphical user interface (GUI). In fact, all tables and graphics for this paper are taken directly from the model GUI. This model has the capability to compare different solar technologies within the same interface, making use of similar cost and finance assumptions. Additionally, the ability to do parametric and sensitivity analysis is central to this model. There are several models within SAM to model the performance of photovoltaic modules and inverters. This paper presents an overview of each PV and inverter model, introduces a new generic model, and briefly discusses the concentrating solar power (CSP) parabolic trough model. A comparison of results using the different PV and inverter models is also presented.

Blair, N.; Mehos, M.; Christensen, C.; Cameron, C.

2008-01-01T23:59:59.000Z

296

Performances of a thermal-storage module in a solar-energy power production perspective: A numerical assessment  

Science Journals Connector (OSTI)

A theoretical model has been developed to describe the cyclic behaviour of a latent-heat thermal-storage module. Attention has been focused on power production applications, where stability of the heat supply ...

C. Bellecci; M. Conti

297

NUMERICAL MODELING OF SPACE PLASMA FLOWS: ASTRONUM-2009 ASP Conference Series, Vol. 4xx, 2010  

E-Print Network (OSTI)

regions in the cold star forming molecular gas on scales from 50 pc down to a few astronomical units operating in the energy cascade in the inertial range of scales (e.g., Kritsuk et al. 2007a). The effective by numerical diffusivity of purely artificial nature. In simulations in- volving magnetic fields, the magnetic

Kritsuk, Alexei

298

Numerical model to determine the composition of H2ONaClCaCl2 fluid inclusions based on  

E-Print Network (OSTI)

Numerical model to determine the composition of H2O­NaCl­CaCl2 fluid inclusions based 2010 Abstract Natural fluids approximated by the H2O­NaCl­CaCl2 system are common in a wide range the compositions of fluid inclusions in the H2O­NaCl­CaCl2 sys- tem based on microthermometric and microanalytical

Bodnar, Robert J.

299

Use of high performance computing resources for underwater acoustic modeling.  

Science Journals Connector (OSTI)

The majority of standard underwater propagation models provide a two?dimensional (range and depth) acoustic field for a single frequency point source. Computational resource demand increases considerably when the three?dimensional acoustic field of a broad?band spatially extended source is of interest. An upgrade of the standard parabolic equationmodel RAM for use in a high?performance computing (HPC) environment is discussed. A benchmarked upgraded version of RAM is used in the Louisiana Optical Network Initiative HPC?environment to model the three?dimensional acoustic field of a seismic airgun array. Four?dimensional visualization (time and space) of the generated data volume is also addressed. [Research supported by the Louisiana Optical Network Initiative TeraGrid Fellowship and the Joint Industry Programme through the International Association of Oil and Gas Producers.

Anca M. Niculescu; Natalia A. Sidorovskaia; Peter Achi; Arslan M. Tashmukhambetov; George E. Ioup; Juliette W. Ioup

2009-01-01T23:59:59.000Z

300

Development of whole-building energy performance models as benchmarks for retrofit projects  

Science Journals Connector (OSTI)

This paper presents a systematic development process of whole-building energy models as performance benchmarks for retrofit projects. Statistical regression-based models and computational performance models are being used for retrofit projects in industry ...

Omer Tugrul Karaguzel; Khee Poh Lam

2011-12-01T23:59:59.000Z

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


301

Course Description The summer school will cover theoretical and numerical methods for modeling microstructure  

E-Print Network (OSTI)

and hands-on work using high performance computing. Syllabus: · Ginzburg-Landau theory and phase field of Physics & Faculty of Science, McGill University, CLUMEQ High Performance Computing Centre, Calcul Qubec

Fabry, Frederic

302

THE PENA BLANCA NATURAL ANALOGUE PERFORMANCE ASSESSMENT MODEL  

SciTech Connect

The Nopal I uranium mine in the Sierra Pena Blanca, Chihuahua, Mexico serves as a natural analogue to the Yucca Mountain repository. The Pena Blanca Natural Analogue Performance Assessment Model simulates the mobilization and transport of radionuclides that are released from the mine and transported to the saturated zone. The Pena Blanca Natural Analogue Performance Assessment Model uses probabilistic simulations of hydrogeologic processes that are analogous to the processes that occur at the Yucca Mountain site. The Nopal I uranium deposit lies in fractured, welded, and altered rhyolitic ash-flow tuffs that overlie carbonate rocks, a setting analogous to the geologic formations at the Yucca Mountain site. The Nopal I mine site has the following analogous characteristics as compared to the Yucca Mountain repository site: (1) Analogous source--UO{sub 2} uranium ore deposit = spent nuclear fuel in the repository; (2) Analogous geology--(i.e. fractured, welded, and altered rhyolitic ash-flow tuffs); (3) Analogous climate--Semiarid to arid; (4) Analogous setting--Volcanic tuffs overlie carbonate rocks; and (5) Analogous geochemistry--Oxidizing conditions Analogous hydrogeology: The ore deposit lies in the unsaturated zone above the water table.

G. Saulnier and W. Statham

2006-04-16T23:59:59.000Z

303

Control of household refrigerators. Part 1: Modeling temperature control performance  

SciTech Connect

Commercial household refrigerators use simple, cost-effective, temperature controllers to obtain acceptable control. A manually adjusted airflow damper regulates the freezer compartment temperature while a thermostat controls operation of the compressor and evaporator fan to regulate refrigerator compartment temperature. Dual compartment temperature control can be achieved with automatic airflow dampers that function independently of the compressor and evaporator fan thermostat, resulting in improved temperature control quality and energy consumption. Under dual control, freezer temperature is controlled by the thermostat while the damper controls refrigerator temperature by regulating airflow circulation. A simulation model is presented that analyzes a household refrigerator configured with a conventional thermostat and both manual and automatic dampers. The model provides a new paradigm for investigating refrigerator systems and temperature control performance relative to the extensive verification testing that is typically done by manufacturers. The effects of each type of control and damper configuration are compared with respect to energy usage, control quality, and ambient temperature shift criteria. The results indicate that the appropriate control configuration can have significant effects and can improve plant performance.

Graviss, K.J.; Collins, R.L.

1999-07-01T23:59:59.000Z

304

Advanced Numerical Weather Prediction Techniques for Solar Irradiance Forecasting : : Statistical, Data-Assimilation, and Ensemble Forecasting  

E-Print Network (OSTI)

Multiscale numerical weather prediction model. Progress inassimilating numerical weather prediction model for solarwith numerical weather prediction models. In: Solar Energy

Mathiesen, Patrick James

2013-01-01T23:59:59.000Z

305

A three-dimensional numerical model of dry convection in an ambient wind field  

E-Print Network (OSTI)

effects of the ambient wind field on convection. Nost of the numerical results are shown to correspond to empirical observations, while some results are unexpected but reasonable. Nechanical and thermal energy equations have been developed... to investigate the effects on convection of an The citations on the following pages follow the tyl of th J* J of ~At * h ' f ambient wind with a vertical shear He also examined the energy interactions between convective flow and nean flows. There were many...

Burgeson, John Carl

2012-06-07T23:59:59.000Z

306

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

E-Print Network (OSTI)

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

Jia, Dongxing 1984-

2012-11-15T23:59:59.000Z

307

Optimization of Computational Performance and Accuracy in 3?D Transient CFD Model for CFB Hydrodynamics Predictions  

Science Journals Connector (OSTI)

This work aims to present a pure 3?D CFD model accurate and efficient for the simulation of a pilot scale CFB hydrodynamics. The accuracy of the model was investigated as a function of the numerical parameters in order to derive an optimum model setup with respect to computational cost. The necessity of the in depth examination of hydrodynamics emerges by the trend to scale up CFBCs. This scale up brings forward numerous design problems and uncertainties which can be successfully elucidated by CFD techniques. Deriving guidelines for setting a computational efficient model is important as the scale of the CFBs grows fast while computational power is limited. However the optimum efficiency matter has not been investigated thoroughly in the literature as authors were more concerned for their models accuracy and validity. The objective of this work is to investigate the parameters that influence the efficiency and accuracy of CFB computational fluid dynamics models find the optimum set of these parameters and thus establish this technique as a competitive method for the simulation and design of industrial large scale beds where the computational cost is otherwise prohibitive. During the tests that were performed in this work the influence of turbulence modeling approach time and space density and discretization schemes were investigated on a 1.2 MWth CFB test rig. Using Fourier analysis dominant frequencies were extracted in order to estimate the adequate time period for the averaging of all instantaneous values. The compliance with the experimental measurements was very good. The basic differences between the predictions that arose from the various model setups were pointed out and analyzed. The results showed that a model with high order space discretization schemes when applied on a coarse grid and averaging of the instantaneous scalar values for a 20 sec period adequately described the transient hydrodynamic behaviour of a pilot CFB while the computational cost was kept low. Flow patterns inside the bed such as the core?annulus flow and the transportation of clusters were at least qualitatively captured.

I. Rampidis; A. Nikolopoulos; N. Koukouzas; P. Grammelis; E. Kakaras

2007-01-01T23:59:59.000Z

308

Numerical Modeling of Speckle Fields: Catching the Visible and the Invisible  

Science Journals Connector (OSTI)

The present paper deals with the numerical simulation of the diffracted field emanating from an optically rough surface illuminated by a spatially coherent white?light source. The colored speckle pattern which can be observed under these circumstances visualizes the 3D structure of the diffracted speckle field and what’s more it allows us appreciate the differences between diffraction regimes i.e. Fresnel rather than Fraunhofer regime. In the paper the 3D structure of near? and far?field diffraction fully developed speckle fields will be explored by numerical simulation in the Mathematica™ environment by using few highly?optimized functions implementing the Rayleigh?Sommerfeld formulation into the built?in FFT (Fast Fourier Transform) algorithm. In the applicability range of the Fresnel approximation the dimensionless Fresnel number fully describes the diffraction regime and the results of the numerical simulation can be simply mapped into the physical world by the appropriate scaling parameters at diffraction plane and along the propagation direction.

Andrea Poggialini; Luigi Bruno

2010-01-01T23:59:59.000Z

309

Mathematical formulation and numerical modeling of wax deposition in pipelines from enthalpy–porosity approach and irreversible thermodynamics  

Science Journals Connector (OSTI)

In the last 10 years, there have been a number of studies in modeling of the deposition processes in flowlines. Most of these models: (1) assume empirical or semi-empirical correlations to predict the pressure drop and temperature profile, (2) ignore the radial convection flow in the layer composed of the two-phase wax and oil (that is the gel layer), and (3) use Fick’s law to describe the diffusion flux of species towards the wall by using the chain rule to relate concentration gradient to temperature gradient. In this work, a rigorous mathematical model for the prediction of wax deposition in pipelines is presented for laminar flow. The transient deposition of each component is calculated from the solution of the coupled momentum, energy and, species balance equations, and a thermodynamic wax precipitation model at the local level. An enthalpy formulation based on a fixed-grid approach is used to approximate the convection flow in the gel layer. We do not use the chain rule to relate composition gradient to temperature gradient in Fick’s law to avoid violating the laws of irreversible thermodynamics. Our diffusion flux expression includes molecular diffusion (concentration gradient is driving force) and thermal diffusion (temperature gradient is driving force) with appropriate diffusion coefficients. This work also includes the description of the numerical solution of the governing equations. Numerical results and features of wax deposition as well as model verification with experimental data are presented in a separate paper.

R. Banki; H. Hoteit; A. Firoozabadi

2008-01-01T23:59:59.000Z

310

Adjoint Sensitivity Analysis for Numerical Weather Prediction  

E-Print Network (OSTI)

Sep 2, 2011 ... Adjoint Sensitivity Analysis for Numerical Weather Prediction: Applications to ... weather variables using numerical weather prediction models.

Alexandru Cioaca

2011-09-02T23:59:59.000Z

311

Current Capabilities of the Fuel Performance Modeling Code PARFUME  

SciTech Connect

The success of gas reactors depends upon the safety and quality of the coated particle fuel. A fuel performance modeling code (called PARFUME), which simulates the mechanical and physico-chemical behavior of fuel particles during irradiation, is under development at the Idaho National Engineering and Environmental Laboratory. Among current capabilities in the code are: 1) various options for calculating CO production and fission product gas release, 2) a thermal model that calculates a time-dependent temperature profile through a pebble bed sphere or a prismatic block core, as well as through the layers of each analyzed particle, 3) simulation of multi-dimensional particle behavior associated with cracking in the IPyC layer, partial debonding of the IPyC from the SiC, particle asphericity, kernel migration, and thinning of the SiC caused by interaction of fission products with the SiC, 4) two independent methods for determining particle failure probabilities, 5) a model for calculating release-to-birth (R/B) ratios of gaseous fission products, that accounts for particle failures and uranium contamination in the fuel matrix, and 6) the evaluation of an accident condition, where a particle experiences a sudden change in temperature following a period of normal irradiation. This paper presents an overview of the code.

G. K. Miller; D. A. Petti; J. T. Maki; D. L. Knudson

2004-09-01T23:59:59.000Z

312

Numerical modeling of buoyancy-driven flows in a rotating cylindrical cavity: Comparison of a finite element model with a spectral model  

SciTech Connect

A finite element model is developed for the prediction of the motion of rotating Boussinesq fluid driven by buoyancy. The computations are performed for the axisymmetric regime in an annular cavity for Reynolds number varying from 0 to 2,500. The results are compared with those of an earlier study of this problem using a spectral Tau-Chebyshev method. The good agreement found assesses the finite element model. Finally, a complementary convergence analysis gives the sensitivity of the model to mesh refinement.

Jaeger, M.; Medale, M.; Randriamanpianina, A. [Centre National de la Recherche Scientifique, Marseille (France)

1996-12-01T23:59:59.000Z

313

Direct-Steam Linear Fresnel Performance Model for NREL's System Advisor Model  

SciTech Connect

This paper presents the technical formulation and demonstrated model performance results of a new direct-steam-generation (DSG) model in NREL's System Advisor Model (SAM). The model predicts the annual electricity production of a wide range of system configurations within the DSG Linear Fresnel technology by modeling hourly performance of the plant in detail. The quasi-steady-state formulation allows users to investigate energy and mass flows, operating temperatures, and pressure drops for geometries and solar field configurations of interest. The model includes tools for heat loss calculation using either empirical polynomial heat loss curves as a function of steam temperature, ambient temperature, and wind velocity, or a detailed evacuated tube receiver heat loss model. Thermal losses are evaluated using a computationally efficient nodal approach, where the solar field and headers are discretized into multiple nodes where heat losses, thermal inertia, steam conditions (including pressure, temperature, enthalpy, etc.) are individually evaluated during each time step of the simulation. This paper discusses the mathematical formulation for the solar field model and describes how the solar field is integrated with the other subsystem models, including the power cycle and optional auxiliary fossil system. Model results are also presented to demonstrate plant behavior in the various operating modes.

Wagner, M. J.; Zhu, G.

2012-09-01T23:59:59.000Z

314

EMEP Intercomparison Study of Numerical Models for Long-Range Atmospheric Transport of Mercury  

E-Print Network (OSTI)

............................... Denmark...NERI G. Petersen, R. Ebinghaus .................. Germany...GKSS J. Pacyna and Oxidants Model, GKSS Research Center, GermanyADOM MSC-E heavy metal regional model, EMEP MSC

315

Initial Testing of a Numerical Ocean Circulation Model Using a Hybrid (Quasi-Isopycnic) Vertical Coordinate  

Science Journals Connector (OSTI)

An ocean circulation model, developed for the study of mesoscale to gyre-scale circulation and heat transport, is described and tested. The model employs density as vertical coordinate except in the immediate vicinity of possible coordinate ...

Rainer Bleck; Douglas B. Boudra

1981-06-01T23:59:59.000Z

316

A Blended Soundproof-to-Compressible Numerical Model for Small- to Mesoscale Atmospheric Dynamics  

Science Journals Connector (OSTI)

A blended model for atmospheric flow simulations is introduced that enables seamless transition from fully compressible to pseudo-incompressible dynamics. The model equations are written in nonperturbation form and integrated using a well-balanced ...

Tommaso Benacchio; Warren P. O’Neill; Rupert Klein

2014-12-01T23:59:59.000Z

317

Numerical Modeling At Neal Hot Springs Geothermal Area (U.S....  

Open Energy Info (EERE)

model was created. The model was created on March 24th 2011 by a consulting reservoir engineer and presented to the DOE's independent reservoir engineer. Upon review the final...

318

THE STATE OF THE ART OF NUMERICAL MODELING OF THERMOHYDROLOGIC FLOW IN FRACTURED ROCK MASSES  

E-Print Network (OSTI)

improving production by hydraulic fracturing 8 the focus otfor fractures. (d) Hydraulic Fracturing: The model has been

Wang, J.S.Y.

2013-01-01T23:59:59.000Z

319

THE STATE OF THE ART OF NUMERICAL MODELING OF THERMOHYDROLOGIC FLOW IN FRACTURED ROCK MASSES  

E-Print Network (OSTI)

geothermal reservoir and wellbore model was used in the history-matching simulations for test wells in Cerro Prieto, Mexico,

Wang, J.S.Y.

2013-01-01T23:59:59.000Z

320

Numerical Modeling of Nonlinear Coupling between Lines/Beams with Multiple Floating Bodies  

E-Print Network (OSTI)

spring model and the three(3) dimensional FE beam model. The coupling of the TLP motion with the reaction force at the tie-down clamp is considered by using exact nonlinear dynamic equations of the motion with the reaction forces modeled with the spring...

Yang, Chan K.

2010-07-14T23:59:59.000Z

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


321

NUMERICAL EXPERIMENTS USING MESONH/FOREFIRE COUPLED ATMOSPHERIC-FIRE MODEL  

E-Print Network (OSTI)

model inputting the wind fields and outputting heat and vapour fluxes to the atmospheric model. Fore mesh. Another originality of the approach is the fire rate of spread model that integrates wind effect of has been developed to add locale atmosphere interaction to the family of fire area simulators

Boyer, Edmond

322

Evaluation of the numerical stability and sensitivity to material parameter variations for several unified constitutive models  

E-Print Network (OSTI)

Material Constants Used In Bodner's Model For Hastelloy-X at 1800' F . Naterial Constants Used In Walker's Model For Hastelloy-X at 1800' F . Material Constants Used In Krieg's Model For Hastelloy-X at 1800 F . Material Constants Used In Miller...'s Model For Hastelloy-X at 1800' F . Page 18 26 30 35 LIST OF FIGURES Fi gure Plots Used to Obtain Material Parameters For Bodner's Model . Page T6 Back Stress and True Stress-Strain Curve Used in Walker's Theory. Plot Used to Determine...

Imbrie, Peter Kenneth

1985-01-01T23:59:59.000Z

323

Performance modeling of the Ballard Mark IV solid polymer electrolyte fuel cell. 1: Mechanistic model development  

SciTech Connect

A parametric model predicting the performance of a solid polymer electrolyte, proton exchange membrane (PEM) fuel cell has been developed using a combination of mechanistic and empirical modeling techniques. This paper details the mechanistic model development. Mass transport properties are considered in the mechanistic development via Stefan-Maxwell equations. Thermodynamic equilibrium potentials are defined using the Nernst equation. Activation overvoltages are defined via a Tafel equation, and internal resistance are defined via the Nernst-Planck equation, leading to a definition of ohmic overvoltage via an Ohm's law equation. The mechanistic model cannot adequately model fuel cell performance, since several simplifying approximations have been used in order to facilitate model development. Additionally, certain properties likely to be observed in operational fuel cells, such as thermal gradients, have not been considered. Nonetheless, the insights gained from the mechanistic assessment of fuel cell processes were found to give the resulting empirical model a firmer theoretical basis than many of the models presently available in the literature. Correlation of the empirical model to actual experimental data was very good.

Amphlett, J.C.; Baumert, R.M.; Mann, R.F.; Peppley, B.A.; Roberge, P.R. (Royal Military College of Canada, Kingston, Ontario (Canada)); Harris, T.J. (Queen's Univ., Kingston, Ontario (Canada))

1995-01-01T23:59:59.000Z

324

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

SciTech Connect

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

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

2009-07-15T23:59:59.000Z

325

Numerical modelling of ground water flow using MODFLOW, Indian Journal of Science, 2013, 2(4), 86-92, www.discovery.org.in  

E-Print Network (OSTI)

management approaches. However, there should be no expectation of a single `true' model, and model outputsRESEARCH Kumar, Numerical modelling of ground water flow using MODFLOW, Indian Journal of Science management or impact of new development scenarios. However, if the modelling studies are not well designed

Kumar, C.P.

326

AMPS, a real-time mesoscale modeling system, has provided a decade of service for scientific and logistical needs and has helped advance polar numerical weather prediction  

E-Print Network (OSTI)

and logistical needs and has helped advance polar numerical weather prediction as well as understanding support for the USAP. The concern at the time was the numerical weather prediction (NWP) guidance-time implementation of the Weather Research and Forecasting model (WRF; Skamarock et al. 2008) to support the U

Howat, Ian M.

327

Development of a GPU-based high-performance radiative transfer model for the Infrared Atmospheric Sounding Interferometer (IASI)  

SciTech Connect

Satellite-observed radiance is a nonlinear functional of surface properties and atmospheric temperature and absorbing gas profiles as described by the radiative transfer equation (RTE). In the era of hyperspectral sounders with thousands of high-resolution channels, the computation of the radiative transfer model becomes more time-consuming. The radiative transfer model performance in operational numerical weather prediction systems still limits the number of channels we can use in hyperspectral sounders to only a few hundreds. To take the full advantage of such high-resolution infrared observations, a computationally efficient radiative transfer model is needed to facilitate satellite data assimilation. In recent years the programmable commodity graphics processing unit (GPU) has evolved into a highly parallel, multi-threaded, many-core processor with tremendous computational speed and very high memory bandwidth. The radiative transfer model is very suitable for the GPU implementation to take advantage of the hardware's efficiency and parallelism where radiances of many channels can be calculated in parallel in GPUs. In this paper, we develop a GPU-based high-performance radiative transfer model for the Infrared Atmospheric Sounding Interferometer (IASI) launched in 2006 onboard the first European meteorological polar-orbiting satellites, METOP-A. Each IASI spectrum has 8461 spectral channels. The IASI radiative transfer model consists of three modules. The first module for computing the regression predictors takes less than 0.004% of CPU time, while the second module for transmittance computation and the third module for radiance computation take approximately 92.5% and 7.5%, respectively. Our GPU-based IASI radiative transfer model is developed to run on a low-cost personal supercomputer with four GPUs with total 960 compute cores, delivering near 4 TFlops theoretical peak performance. By massively parallelizing the second and third modules, we reached 364x speedup for 1 GPU and 1455x speedup for all 4 GPUs, both with respect to the original CPU-based single-threaded Fortran code with the -O{sub 2} compiling optimization. The significant 1455x speedup using a computer with four GPUs means that the proposed GPU-based high-performance forward model is able to compute one day's amount of 1,296,000 IASI spectra within nearly 10 min, whereas the original single CPU-based version will impractically take more than 10 days. This model runs over 80% of the theoretical memory bandwidth with asynchronous data transfer. A novel CPU-GPU pipeline implementation of the IASI radiative transfer model is proposed. The GPU-based high-performance IASI radiative transfer model is suitable for the assimilation of the IASI radiance observations into the operational numerical weather forecast model.

Huang Bormin, E-mail: bormin@ssec.wisc.ed [Space Science and Engineering Center, University of Wisconsin, Madison (United States); Mielikainen, Jarno [Department of Computer Science, University of Eastern Finland, Kuopio (Finland); Oh, Hyunjong; Allen Huang, Hung-Lung [Space Science and Engineering Center, University of Wisconsin, Madison (United States)

2011-03-20T23:59:59.000Z

328

A GIS tool for the evaluation of the precipitation forecasts of a numerical weather prediction model using satellite data  

Science Journals Connector (OSTI)

In this study, the possibility of implementing Geographic Information Systems (GIS) for developing an integrated and automatic operational system for the real-time evaluation of the precipitation forecasts of the numerical weather prediction model BOLAM (BOlogna Limited Area Model) in Greece, is examined. In fact, the precipitation estimates derived by an infrared satellite technique are used for real-time qualitative and quantitative verification of the precipitation forecasts of the model BOLAM through the use of a GIS tool named as precipitation forecasts evaluator (PFE). The application of the developed tool in a case associated with intense precipitation in Greece, suggested that PFE could be a very important support tool for nowcasting and very short-range forecasting of such events.

Haralambos Feidas; Themistoklis Kontos; Nikolaos Soulakellis; Konstantinos Lagouvardos

2007-01-01T23:59:59.000Z

329

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

Science Journals Connector (OSTI)

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

K. Richter; H. Rosemann

2013-01-01T23:59:59.000Z

330

Waste Form Degradation Model Integration for Engineered Materials Performance  

Energy.gov (U.S. Department of Energy (DOE))

The collaborative approach to the glass and metallic waste form degradation modeling activities includes process model development (including first-principles approaches) and model integration—both...

331

Generation of baroclinic tide energy in a global three-dimensional numerical model with different spatial grid resolutions  

Science Journals Connector (OSTI)

Abstract We examine the global distribution of energy conversion rates from barotropic to baroclinic tides using a hydrostatic sigma-coordinate numerical model with a special attention to the dependence on the model grid resolution as well as the model topography resolution. A series of numerical experiments shows that the baroclinic tidal energy conversion rate increases almost exponentially with the decrease of the horizontal grid spacing, namely, from 1/5° to 1/20°. The baroclinic tidal energy conversion rates for the semidiurnal tidal constituents (M2, S2) are more sensitive to the horizontal grid spacing than those for the diurnal tidal constituents (K1, O1), reflecting the difference of their horizontal wavelengths. The sensitivity of the baroclinic tidal energy conversion rate to the horizontal grid spacing is also dependent on the generation sites of baroclinic tides; it becomes very sensitive in the regions characterized by geologically young seafloor having numerous small-scale rough topographic features such as the Mid-Atlantic Ridges, the eastern Pacific Ridges, and the Mid-Indian Ocean Ridges, whereas it is less sensitive in the regions such as the Indonesian Archipelago, and the western Pacific Ocean. The difference of the sensitivity can be best explained in terms of the value of the forcing function that is proportional to the square of the vertical velocity caused by barotropic tidal currents interacting with high-pass filtered bottom topography. Using the extrapolated value of the forcing function that takes into account all the topographic features generating baroclinic tides, we present the global distribution of the baroclinic tidal energy conversion rates in the limit of zero horizontal grid spacing.

Yoshihiro Niwa; Toshiyuki Hibiya

2014-01-01T23:59:59.000Z

332

Coalescing neutron stars - a step towards physical models III. Improved numerics and different neutron star masses and spins  

E-Print Network (OSTI)

(Abridged) In this paper we present a compilation of results from our most advanced neutron star merger simulations, including a description of the employed numerical procedures and a more complete overview over a large number of computed models. The three-dimensional hydrodynamic simulations were done with a code based on the Piecewise Parabolic Method with up to five levels of nested Cartesian grids. The simulations are basically Newtonian, but gravitational-wave emission and the corresponding back-reaction are taken into account. The use of a physical nuclear equation of state allows us to follow the thermodynamic history of the stellar medium and to compute the energy and lepton number loss due to the emission of neutrinos. The computed models differ concerning the neutron star masses and mass ratios, the neutron star spins, the numerical resolution expressed by the cell size of the finest grid and the number of grid levels, and the calculation of the temperature from the solution of the entropy equation instead of the energy equation. Our simulations show that the details of the gravitational-wave emission are still sensitive to the numerical resolution, even in our highest-quality calculations. The amount of mass which can be ejected from neutron star mergers depends strongly on the angular momentum of the system. Our results do not support the initial conditions of temperature and proton-to-nucleon ratio assumed in recent work for producing a solar r-process pattern for nuclei around and above the A approx 130 peak. The improved models confirm our previous conclusion that gamma-ray bursts are not powered by neutrino emission during the dynamical phase of the merging of two neutron stars.

M. Ruffert; H. -Th. Janka

2001-06-13T23:59:59.000Z

333

Computational performance of ultra-high-resolution capability in the Community Earth System Model  

Science Journals Connector (OSTI)

With the fourth release of the Community Climate System Model, the ability to perform ultra-high-resolution climate simulations is now possible, enabling eddy-resolving ocean and sea-ice models to be coupled to a finite-volume atmosphere model for a ... Keywords: Earth system modeling, Performance engineering, application optimization, climate modeling, high-resolution

John M. Dennis; Mariana Vertenstein; Patrick H. Worley; Arthur A. Mirin; Anthony P. Craig; Robert Jacob; Sheri Mickelson

2012-02-01T23:59:59.000Z

334

THE STATE OF THE ART OF NUMERICAL MODELING OF THERMOHYDROLOGIC FLOW IN FRACTURED ROCK MASSES  

E-Print Network (OSTI)

Doughty, 1979a, Aquifer thermal energy storage--a numericalical modeling of thermal energy storage in aquifers.Presented at the Thermal Energy Storage in Aquifers

Wang, J.S.Y.

2013-01-01T23:59:59.000Z

335

Analysis of vadose zone tritium transport from an underground storage tank release using numerical modeling and geostatistics  

SciTech Connect

Numerical and geostatistical analyses show that the artificial smoothing effect of kriging removes high permeability flow paths from hydrogeologic data sets, reducing simulated contaminant transport rates in heterogeneous vadose zone systems. therefore, kriging alone is not recommended for estimating the spatial distribution of soil hydraulic properties for contaminant transport analysis at vadose zone sites. Vadose zone transport if modeled more effectively by combining kriging with stochastic simulation to better represent the high degree of spatial variability usually found in the hydraulic properties of field soils. However, kriging is a viable technique for estimating the initial mass distribution of contaminants in the subsurface.

Lee, K.H.

1997-09-01T23:59:59.000Z

336

Numerical modeling of quasitransient backward Raman amplification of laser pulses in moderately undercritical plasmas with multicharged ions  

SciTech Connect

It was proposed recently that powerful optical laser pulses could be efficiently compressed through backward Raman amplification in ionized low density solids, in spite of strong damping of the resonant Langmuir wave. It was argued that, even for nonsaturated Landau damping of the Langmuir wave, the energy transfer from the pump laser pulse to the amplified seed laser pulse can nevertheless be highly efficient. This work numerically examines such regimes of strong damping, called quasitransient regimes, within the simplest model that takes into account the major effects. The simulations indicate that compression of powerful optical laser pulses in ionized low density solids indeed can be highly efficient.

Balakin, A. A.; Fraiman, G. M. [Institute of Applied Physics RAS, Nizhnii Novgorod 603950 (Russian Federation); Fisch, N. J. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08540 (United States); Malkin, V. M. [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08540 (United States); Toroker, Z. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

2011-10-15T23:59:59.000Z

337

Establishment of Stress-Permeabilty relationship of fractured rock mass by numerical modeling  

Office of Scientific and Technical Information (OSTI)

Accepted for publication in International Journal of Rock Mechanics & Mining Sciences Accepted for publication in International Journal of Rock Mechanics & Mining Sciences Stress-Dependent Permeability of Fractured Rock Masses: A Numerical Study Ki-Bok Min *1 , J Rutqvist 2 , Chin-Fu Tsang 2 , and Lanru Jing 1 1 Engineering Geology and Geophysics Research Group, Royal Institute of Technology (KTH), Stockholm, Sweden 2 Earth Sciences Division, Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA, USA * corresponding author. Tel.: +46-8-790-7919; fax: +46-8-790-6810. E-mail address: kibok@kth.se (Ki-Bok Min) 1 Abstract We investigate the stress-dependent permeability issue in fractured rock masses considering the effects of nonlinear normal deformation and shear dilation of fractures using a two-dimensional

338

Intercomparison of Single-Column Numerical Models for the Prediction of Radiation Fog  

E-Print Network (OSTI)

layers of the atmosphere. Current NWP models poorly forecast the life cycle of fog, and improved NWP models exist in the surface boundary layer before the fog onset, particularly in cases with light winds before improving the analysis and prediction of fog (e.g., Benjamin et al. 2004; Fowler et al. 2006

Ribes, Aurélien

339

Geothermics 33 (2004) 457476 Numerical modeling of transient Basin and Range  

E-Print Network (OSTI)

.Drillingindicateshightemperatures(>190 C)at2.5­3.0 kmdepth along a strike length of at least 20 km along the west side of the valley model consists of two mountain ranges (1 km relief from the valley floor) separated by a thick sequence exist on a steady-state basis. The models show some features seen in Dixie Valley, Naveda

Southern Methodist University

340

A two-dimensional numerical model of dry convection with three-dimensional dynamics  

E-Print Network (OSTI)

symmetric model to simulate a bucyant mass of fluid embedded in an ambient The format and style of this thesis follow those of the Journal of Atmos heric Sciences. fluid of uniform density. The results from Ogura's model exhibited the shape preserving...

Weyman, James Charles

1978-01-01T23:59:59.000Z

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


341

NUMERICAL MODELLING OF AUTOGENOUS HEALING AND RECOVERY OF MECHANICAL PROPERTIES IN ULTRA-HIGH  

E-Print Network (OSTI)

, hydro-chemo- mechanical coupling ABSTRACT Cracks, caused by shrinkage or external loading, reduce. In this study, a hydro-chemo-mechanical model was developed to simulate autogenous healing by further hydration into water was modelled based on micro-mechanical observations. The diffusion process has been simulated

Boyer, Edmond

342

THE PENA BLANCA NATURAL ANALOGUE PERFORMANCE ASSESSMENT MODEL  

SciTech Connect

The Nopal I uranium mine in the Sierra Pena Blanca, Chihuahua, Mexico serves as a natural analogue to the Yucca Mountain repository. The Pena Blanca Natural Analogue Performance Assessment Model simulates the mobilization and transport of radionuclides that are released from the mine and transported to the saturated zone. the Pena Blanca Natural Analogue Model uses probabilistic simulations of hydrogeologic processes that are analogous to the processes that occur at the Yucca Mountain site. The Nopal I uranium deposit lies in fractured, welded, and altered rhyolitic ash flow tuffs that overlie carbonate rocks, a setting analogous to the geologic formations at the Yucca Mountain site. The Nopal I mine site has the following characteristics as compared to the Yucca Mountain repository site. (1) Analogous source: UO{sub 2} uranium ore deposit = spent nuclear fuel in the repository; (2) Analogous geologic setting: fractured, welded, and altered rhyolitic ash flow tuffs overlying carbonate rocks; (3) Analogous climate: Semiarid to arid; (4) Analogous geochemistry: Oxidizing conditions; and (5) Analogous hydrogeology: The ore deposit lies in the unsaturated zone above the water table. The Nopal I deposit is approximately 8 {+-} 0.5 million years old and has been exposed to oxidizing conditions during the last 3.2 to 3.4 million years. The Pena Blanca Natural Analogue Model considers that the uranium oxide and uranium silicates in the ore deposit were originally analogous to uranium-oxide spent nuclear fuel. The Pena Blanca site has been characterized using field and laboratory investigations of its fault and fracture distribution, mineralogy, fracture fillings, seepage into the mine adits, regional hydrology, and mineralization that shows the extent of radionuclide migration. Three boreholes were drilled at the Nopal I mine site in 2003 and these boreholes have provided samples for lithologic characterization, water-level measurements, and water samples for laboratory analysis of the saturated zone water chemistry. The results of the field investigations and laboratory analyses of rock and water samples collected at Nopal I are used to calibrate the Pena Blanca Natural Analogue Model.

G.J. Saulnier Jr; W. Statham

2006-03-10T23:59:59.000Z

343

Coupled numerical modelling of power loss generation in busbar system of low-voltage switchgear  

Science Journals Connector (OSTI)

Abstract This paper presents a coupled mathematical model of the heat transfer processes in an electric switchgear. The considered problem required the computation of the detailed distribution of the power losses and all the heat transfer modes (radiation, convection, and conduction) within a unit. In this complex thermal analysis, different definitions of electric busbar heating were considered and compared. The most advanced model, which couples the thermal and electromagnetic fields in two ways, was also compared with the simplified approaches. First, the direct current loading of the busbar, which neglected the alternating current effects, was considered. Second, models that included only one method of coupling were calculated for different assumed average busbar temperatures. Finally, the model with the two-way coupling, which took the eddy currents and proximity effects into account, was simulated using an iteration loop between the electromagnetic and fluid flow solvers. This study employed a geometrical model of industrial low-voltage switchgear. The presented mathematical model was also validated against temperature measurements carried out by a certified laboratory. The obtained results show that a fully coupled model produces very satisfactory agreement between computed and experimental data.

Mateusz Bedkowski; Jacek Smolka; Krzysztof Banasiak; Zbigniew Bulinski; Andrzej J. Nowak; Tomasz Tomanek; Adam Wajda

2014-01-01T23:59:59.000Z

344

Ventilation performance prediction for buildings: Model Assessment Qingyan Chena,b,*  

E-Print Network (OSTI)

1 Ventilation performance prediction for buildings: Model Assessment Qingyan Chena,b,* , Kisup Leeb building, but cannot provide detailed flow information in a room. The zonal model can be useful when a user ventilation systems for buildings requires a suitable model to assess system performance. The performance can

Chen, Qingyan "Yan"

345

Efficient Conservative Numerical Schemes for 1D Nonlinear Spherical Diffusion Equations with Applications in Battery Modeling  

E-Print Network (OSTI)

Mathematical models of batteries which make use of the intercalation of a species into a solid phase need to solve the corresponding mass transfer problem. Because solving this equation can significantly add to the ...

Zeng, Yi

346

Numerical simulations and predictive models of undrained penetration in soft soils  

E-Print Network (OSTI)

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

Shi, Han

2005-11-01T23:59:59.000Z

347

NUMERICAL MODELING FOR THE FORMATION MECHANISM OF 3D TOPOGRAPHY ON MICROBIAL MAT SURFACES  

E-Print Network (OSTI)

though, that nutrient limitation coupled with fluid motion may play a key role as a physical control. Under this model, competitions of nutrients were setup among growing microbial communities, which later evolve into specially arranged, 3D mats. However...

Patel, Harsh Jay

2013-09-27T23:59:59.000Z

348

Mathematical Modelling and Numerical Simulation of Marine Ecosystems With Applications to Ice Algae.  

E-Print Network (OSTI)

??Sea-ice ecosystem modelling is a novel field of research. In this thesis, the main organism studied is sea-ice algae. A basic introduction to algae and… (more)

Wickramage, Shyamila Iroshi Perera

2013-01-01T23:59:59.000Z

349

Numerical modeling of the ignition of a liquid hydrocarbon layer by a radiant heat pulse  

Science Journals Connector (OSTI)

A gas-phase model of radiative ignition of a flammable liquid is developed, allowing for absorption of the radiant flux in the gas phase. Using motor fuels (gasoline and diesel fuel), as examples, we demonstra...

Yu. V. Agabekov; F. G. Yagafarov

350

Detailed numerical modeling of chemical and thermal nonequilibrium in hypersonic flows  

SciTech Connect

Interest in hypersonic flows has created a large demand for physicochemical models for air flow computations around reentry bodies. Detailed physicochemical models for air in chemical and thermal nonequilibrium are needed for a realistic prediction of hypersonic flowfields. In this paper we develop a model, based on elementary physicochemical processes, for a detailed description of chemical nonequilibrium together with the excitation of internal DOFs. This model is implemented in a 2D Navier-Stokes code in order to show the strong influence of thermal nonequilibrium on the flowfields. The algorithm presented here is based on a fully conservative discretization of the inviscid fluxes in the conservation equations and uses the chain rule conservation law form for the viscous fluxes. The large system of ordinary differential and algebraic equations resulting from the spatial discretization is solved by a time-accurate semiimplicit extrapolation method. 34 refs.

Riedel, U.; Maas, U.; Warnatz, J. (Stuttgart Univ. (Germany))

1993-03-01T23:59:59.000Z

351

A numerical model for ultimate soil resistance to an untrenched pipeline under ocean currents  

Science Journals Connector (OSTI)

One of the main concerns for pipeline on-bottom stability design is to properly predict ultimate soil resistance in severe ocean environments. A plane-strain finite element model ... the partially-embedded pipeli...

Fu-ping Gao ???; Xi-ting Han ???; Shu-ming Yan ???

2012-06-01T23:59:59.000Z

352

Numerical Modeling of the Transient Thermal Interference of Vertical U-Tube Haet Exchangers  

E-Print Network (OSTI)

installation separation range. Non-homogenous media were modeled by varying backfill thermal conductivity. Maximum heat transfer was achieved with a fictitious backfill thermal conductivity of 1,000 W/m-K, while measured bentonite backfill conductivities were...

Muraya, Norman K.

353

Photochemical Numerics for Global-Scale Modeling: Fidelity and GCM Testing  

Science Journals Connector (OSTI)

Atmospheric photochemistry lies at the heart of global-scale pollution problems, but it is a nonlinear system embedded in nonlinear transport and so must be modeled in three dimensions. Total earth grids are massive and kinetics require dozens of ...

Scott Elliott; Xuepeng Zhao; Richard P. Turco; Chih-Yue Jim Kao; Mei Shen

1995-03-01T23:59:59.000Z

354

Development and numerical implementation of nonlinear viscoelastic-viscoplastic model for asphalt materials  

E-Print Network (OSTI)

pavements is illustrated using finite element simulations. The constitutive model developed in this study can describe the behavior of asphalt materials (asphalt binder, asphalt mastic and mixtures) under various testing conditions. This study also achieved...

Huang, Chien-Wei

2009-05-15T23:59:59.000Z

355

Evaluation of Precipitation from Numerical Weather Prediction Models and Satellites Using Values Retrieved from Radars  

Science Journals Connector (OSTI)

Precipitation is evaluated from two weather prediction models and satellites, taking radar-retrieved values as a reference. The domain is over the central and eastern United States, with hourly accumulated precipitation over 21 days for the ...

Slavko Vasi?; Charles A. Lin; Isztar Zawadzki; Olivier Bousquet; Diane Chaumont

2007-11-01T23:59:59.000Z

356

NUMERICAL MODEL OF TRANSIENT TWO-PHASE FLOW IN A WELLBORE  

E-Print Network (OSTI)

Wellbore storage in geothermal wells: presented at 1979two-phase flow in a geothermal well has been modelled with asteam water flow in geothermal wells: Journal of Petroleum

Miller, Constance W.

2012-01-01T23:59:59.000Z

357

The numerical solution of a nickel-cadmium battery cell model using the method of lines  

E-Print Network (OSTI)

systems of ODE's, this scheme may be preferable. 3. Conduction in Two Connected Slabs with Different Thermal Conductivities The mathematical modeling of the Ni-Cd battery cell results in a multi-domain problem. Solution of multi domain PDE's using... systems of ODE's, this scheme may be preferable. 3. Conduction in Two Connected Slabs with Different Thermal Conductivities The mathematical modeling of the Ni-Cd battery cell results in a multi-domain problem. Solution of multi domain PDE's using...

Hailu, Teshome

2012-06-07T23:59:59.000Z

358

A Global Time-Dependent Model of Thunderstorm Electricity. Part I: Mathematical Properties of the Physical and Numerical Models  

Science Journals Connector (OSTI)

A time-dependent model that simulates the interaction of a thunderstorm with its electrical environment is introduced. The model solves the continuity equation of the Maxwell current density that includes conduction, displacement, and source ...

G. L. Browning; I. Tzur; R. G. Roble

1987-08-01T23:59:59.000Z

359

Satellite Data Assimilation in Numerical Weather Prediction Models. Part I: Forward Radiative Transfer and Jacobian Modeling in Cloudy Atmospheres  

Science Journals Connector (OSTI)

Satellite data assimilation requires rapid and accurate radiative transfer and radiance gradient models. For a vertically stratified scattering and emitting atmosphere, the vector discrete-ordinate radiative transfer model (VDISORT) was developed ...

Fuzhong Weng; Quanhua Liu

2003-11-01T23:59:59.000Z

360

Numerical modeling of a 2K J-T heat exchanger used in Fermilab Vertical Test Stand VTS-1  

SciTech Connect

Fermilab Vertical Test Stand-1 (VTS-1) is in operation since 2007 for testing the superconducting RF cavities at 2 K. This test stand has single layer coiled finned tubes heat exchanger before J-T valve. A finite difference based thermal model has been developed in Engineering Equation Solver (EES) to study its thermal performance during filling and refilling to maintain the constant liquid level of test stand. The model is also useful to predict its performance under other various operating conditions and will be useful to design the similar kind of heat exchanger for future needs. Present paper discusses the different operational modes of this heat exchanger and its thermal characteristics under these operational modes. Results of this model have also been compared with the experimental data gathered from the VTS-1 heat exchanger and they are in good agreement with the present model.

Gupta, Prabhat Kumar [Raja Ramanna Centre for Advanced Technology (RRCAT), Indore (MP), India; Rabehl, Roger [FNAL

2014-07-01T23:59:59.000Z

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


361

Effects of Localized Energy Extraction in an Idealized, Energetically Complete Numerical Model of an Ocean-Estuary Tidal System  

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

localized energy extraction in an localized energy extraction in an idealized, energetically complete numerical model of an ocean-estuary tidal system MHK Instrumentation, Measurement & Computer Modeling Workshop, Broomfield CO, July 10 2012 Mitsuhiro Kawase and Marisa Gedney Northwest National Marine Renewable Energy Center / School of Oceanography University of Washington Seattle WA 98195 United States * Far-field (Estuary-wide) - Changes in the tidal range - Changes in tidal currents ï‚— Near-field (Vicinity of the Device) ï‚— Flow redirection ï‚— Interaction with marine life ï‚— Impact on bottom sediments and benthos Environmental Effects of Tidal Energy Extraction * Reduction in tidal range can permanently expose/submerge tidal flats, altering nearshore habitats * Reduction in kinetic energy of

362

Accelerating Energy Savings Performance Contracting Through Model Statewide Programs  

Energy.gov (U.S. Department of Energy (DOE))

Provides suggestions on how to accelerateEnergy Savings Performance Contracting programs and information about the types of assistance provided under the 'Accelerated Energy Savings Performance Contracting' initiative. Author: Energy Services Coalition

363

Synthesis of Numerical Methods for Modeling Wave Energy Converter-Point Absorbers: Preprint  

SciTech Connect

During the past few decades, wave energy has received significant attention among all ocean energy formats. Industry has proposed hundreds of prototypes such as an oscillating water column, a point absorber, an overtopping system, and a bottom-hinged system. In particular, many researchers have focused on modeling the floating-point absorber as the technology to extract wave energy. Several modeling methods have been used such as the analytical method, the boundary-integral equation method, the Navier-Stokes equations method, and the empirical method. However, no standardized method has been decided. To assist the development of wave energy conversion technologies, this report reviews the methods for modeling the floating-point absorber.

Li, Y.; Yu, Y. H.

2012-05-01T23:59:59.000Z

364

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

Science Journals Connector (OSTI)

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

Isaac K. Gamwo; Yong Liu

2010-03-10T23:59:59.000Z

365

Temporal characteristics of resonant surface polaritons in superlensing planar double-negative slabs: Development of analytical schemes and numerical models  

Science Journals Connector (OSTI)

The temporal behavior of electric fields in arbitrary double-negative planar slabs is systematically investigated in this paper, from both analytical and numerical perspectives. Concerning infinite slabs, a set of exact expressions for an exponential current excitation is derived through an efficient complex analysis, and an integrated study of surface polariton frequencies is performed. Subsequently, the significant case of a source with a random spatial profile is explored in order to obtain rigorous relations for the field and transient phenomena damping time with respect to problem parameters. On the other hand, a robust finite-difference time-domain methodology is introduced for the comprehensive examination of finite slabs, whose numerical simulations dictate the adoption of a resonatorlike discipline. This inevitable, yet very instructive, convention is physically justified by the almost perfect surface mode reflections at the edges of the slab. In this manner, the proposed formulation reveals a prominent increase in the excited polariton amplitude, relative to the corresponding infinite arrangements, which leads to larger transient times.

Dimitrios L. Sounas; Nikolaos V. Kantartzis; Theodoros D. Tsiboukis

2007-10-17T23:59:59.000Z

366

Efficient Dynamic Modeling, Numerical Optimal Control and Experimental Results for Various Gaits  

E-Print Network (OSTI)

. A fully three- dimensional dynamical model of Sony's four-legged robot is used to state an optimal control robots is still a challenge. For a given gait pattern, landing time and point of each leg are prescribed, i.e. they depend on parameters. The trajectory of each joint between lift-off and landing

Stryk, Oskar von

367

Numerical Modelling of Tide-Surge Interaction in the Bay of Bengal  

Science Journals Connector (OSTI)

...tropical cyclone led to severe inland flooding. This is one of the few events for which...response are correctly reproduced. A model simulation is also made of the surge that occurred...level and eyewitness accounts of inland flooding. The principal requirement for the operational...

1985-01-01T23:59:59.000Z

368

Mathematical Modelling and Numerical Analysis Will be set by the publisher Modelisation Mathematique et Analyse Numerique  

E-Print Network (OSTI)

´ematique et Analyse Num´erique A NULL CONTROLLABILITY DATA ASSIMILATION METHODOLOGY APPLIED TO A LARGE SCALE assimilation refers to any methodology that uses partial observational data and the dynamics of a system for estimating the model state or its parameters. We consider here a non classical approach to data assimilation

Osses, Axel

369

Electrochimica Acta 51 (2006) 31393150 Direct numerical simulation (DNS) modeling of PEFC electrodes  

E-Print Network (OSTI)

Elsevier Ltd. All rights reserved. Keywords: Polymer electrolyte fuel cell; Cathode catalyst layer; Pore. The fuel (i.e. hydrogen) and oxidant (i.e. oxygen) react electrochemically in the active catalyst layers) model is developed to achieve pore-level description of polymer electrolyte fuel cell (PEFC) electrodes

370

Model Validation and Spatial Interpolation by Combining Observations with Outputs from Numerical  

E-Print Network (OSTI)

""r,c,rn The authors are for hel]JfuI #12;Abstract Constructing maps of pollution levels is vital for air quality concentrations. Key tlJords: air pollution, Ba~yesian inference, change of support, likelihood approaches, Matern Resolutions 2.5 Modeling a Nonstationary Covariance . 3 Estimation 3.1 Algorithm 4 Application: Air Pollution

Washington at Seattle, University of

371

Analysis of mid-tropospheric carbon monoxide data using a three- dimensional Global atmospheric Chemistry numerical Model  

SciTech Connect

The GChM atmospheric chemistry and transport model has been used to analyze the mid-tropospheric CO dataset obtained from NASA`s Measurement of Air Pollution by Satellites (MAPS) program. Fourteen simulations with a 3.75 horizontal resolution have been performed, including a base case and 13 sensitivity runs. The model reproduces many, but not all, of the major features of the MAPS dataset. Locations of peak CO mixing ratios associated with biomass burning as observed in the MAPS experiment are slightly farther south than the model result, indicating either greater horizontal transport than present in the model representation or a spatial difference between the location of modeled biomass fires and actual fires. The current version of GChM was shown to be relatively insensitive to the magnitude of the prescribed NO{sub x} and O{sub 3} global distributions and very insensitive to the depth of the mixed layer as parameterized in the model. Cloud convective transport was shown to play an important role in venting boundary layer CO to the free troposphere. This result agrees with prior meteorological analyses of the MAPS dataset that have-indirectly inferred the presence of convective activity through satellite-based information. Work is continuing to analyze the results of these simulations further and to perform more detailed comparisons between model results and MAPS data.

Easter, R.C.; Saylor, R.D.; Chapman, E.G.

1993-12-01T23:59:59.000Z

372

Development and validation of a vertically two-dimensional mesoscale numerical model  

E-Print Network (OSTI)

because the model is dry. The equations are as follows: dv " ? 1 1 d dv f k X V ? ? Vp ? g Vz + ? ~ ? (pK ? ), (2) dt P pH ds m ds pgH do dn d o + 'it ~ pV + ? (ns) + p V ~ VH = 0 dt ds P H (4) dT . H Q sg ? + d t C p C p pRT The symbols... of the model. The remaining variables have been previously defined. 15 The finite difference equations are as follows: ~ H (o V (i, k) = H(i+1) * ( p(i+1, k) + p(i, k) ) * u(i+1, k) ? H(i) * ( p(i, k) + p (i-l, k) ) * u(i, k) / ( 2 a DX ) = DV(i k) (I...

Walters, Michael Kent

2012-06-07T23:59:59.000Z

373

Storm surge analysis using numerical and statistical techniques and comparison with NWS model SLOSH  

E-Print Network (OSTI)

. Most of the coastal basins that make up the estuaries along the Texas Gulf coast are very shallow, with depths that are often no more than a meter. In addition to the shallow bay depths, the topography of coastal lands is that of flat coastal plains... stress for a well-developed hurricane moving towards Texas coast ........................................................................................ 28 Fig. 3-1 SLOSH model basins for the East and Gulf coastlines of the U...

Aggarwal, Manish

2005-11-01T23:59:59.000Z

374

Numerical modeling of a thermohydrochemical (T-H-C) coupling and the implications to radionuclide transport.  

SciTech Connect

Thermohydrochemical (T-H-C) processes result from the placement of heat-generating radioactive materials in unsaturated, fractured geologic materials. The placement of materials in the proposed Yucca Mountain repository will result in complex environmental conditions. Simple models are developed liking the thermohydrological effects simulated with TOUGHZ to system chemistry, with an example presented for chloride. Perturbations to near-field chemistry could have a significant impact on the migration of actinides and fission products in geologic materials. Various conceptual models to represent fractures are utilized in TOUGHZ simulations of thermohydrological processes. The simulated moisture redistribution is then coupled to simple chemical models to demonstrate the potential magnitude of T-H-C processes. The concentration of chloride in solution (returning to the engineered barrier system) is demonstrated, in extreme cases, to exceed 100,000 mg/L. The implication is that the system (typically ambient chemical and hydrological conditions) in which radionuclide transport is typically simulated and measured may be significantly different from the perturbed system.

Esh, D. W.; Scheetz, B. E.

1999-09-21T23:59:59.000Z

375

Numerical Model for the Deformation of Nucleated Cells by Optical Stretchers  

E-Print Network (OSTI)

In this paper, we seek to model the deformation of nucleated cells by single diode-laser bar optical stretchers. We employ a recently developed computational model, the Dynamic Ray-Tracing method, to determine the stress distribution induced by the applied optical forces on a capsule encapsulating a nucleus of different optical properties. These forces are shape dependent and can deform real non-rigid objects; thus resulting in a dynamically changing optical stress distribution with cell and nucleus deformation. Chinese hamster ovary cell is a common biological cell that is of interest to the biomedical community because of their use in recombinant protein therapeutics and is an example of a nucleated cell. To this end, we model chinese hamster ovary cells as two three-dimensional elastic capsules of variable inner capsule size immersed in a fluid where the hydrodynamic forces are calculated using the Immersed Boundary Method. Our results show that the presence of a nucleus has a major effect on the force dis...

Sraj, Ihab; Marr, David W M; Eggleton, Charles D

2015-01-01T23:59:59.000Z

376

Numerical Model for the Deformation of Nucleated Cells by Optical Stretchers  

E-Print Network (OSTI)

In this paper, we seek to model the deformation of nucleated cells by single diode-laser bar optical stretchers. We employ a recently developed computational model, the Dynamic Ray-Tracing method, to determine the stress distribution induced by the applied optical forces on a capsule encapsulating a nucleus of different optical properties. These forces are shape dependent and can deform real non-rigid objects; thus resulting in a dynamically changing optical stress distribution with cell and nucleus deformation. Chinese hamster ovary cell is a common biological cell that is of interest to the biomedical community because of their use in recombinant protein therapeutics and is an example of a nucleated cell. To this end, we model chinese hamster ovary cells as two three-dimensional elastic capsules of variable inner capsule size immersed in a fluid where the hydrodynamic forces are calculated using the Immersed Boundary Method. Our results show that the presence of a nucleus has a major effect on the force distribution on the cell surface and the net deformation. Scattering and gradient forces are reported for different nucleus sizes and the effect of nucleus size on the cell deformation is discussed.

Ihab Sraj; Joshua Francois; David W. M. Marr; Charles D. Eggleton

2015-01-15T23:59:59.000Z

377

Summary Results for Brine Migration Modeling Performed by LANL, LBNL and SNL for the Used Fuel Disposition Program  

Energy.gov (U.S. Department of Energy (DOE))

The report summarizes laboratory and field observations and numerical modeling related to coupledprocesses involving brine and vapor migration in geologic salt, focusing on recent developments and...

378

Memory consistency models for high performance distributed computing  

E-Print Network (OSTI)

This thesis develops a mathematical framework for specifying the consistency guarantees of high performance distributed shared memory multiprocessors. This framework is based on computations, which specify the operations ...

Luchangco, Victor

2001-01-01T23:59:59.000Z

379

NREL Software Models Performance of Wind Plants (Fact Sheet)...  

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

effects of weather patterns, turbulence, and complex terrain on the performance of wind turbines and plants. SOWFA simulates fluid dynam- ics on scales from regional weather to...

380

The preparation of landslide map by Landslide Numerical Risk Factor (LNRF) model and Geographic Information System (GIS)  

Science Journals Connector (OSTI)

Abstract One of the risks to threaten mountainous areas is that hillslope instability caused damage to lands. One of the most dangerous instabilities is mass movement and much movement occurs due to slip. The aim of this study is zonation of landslide hazards in a basin of the Ardebil province, the eastern slopes of Sabalan, Iran. Geological and geomorphologic conditions, climate and type of land use have caused susceptibility of this watershed to landslides. Firstly, maps of the main factors affecting landslide occurrence including slope, distance from faults, lithology, elevation and precipitation were prepared and digitized. Then, by using interpretation of aerial photos and satellite images and field views, the ground truth map of landslides was prepared. Each basic layer (factor) and landslide map were integrated to compute the numeric value of each factor with the help of a Landslide Numerical Risk Factor (LNRF) model and landslide occurrence percent obtained in different units from each of the maps. Finally, with overlapping different data layers, a landslide hazard zonation map was prepared. Results showed that 67.85% of the basin has high instability, 7.76% moderate instability and 24.39% low instability.

Ali Mohammadi Torkashvand; Akram Irani; Jaliledin Sorur

2014-01-01T23:59:59.000Z

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


381

Numerical modelling of salinity variations due to wind and thermohaline forcing in the Persian Gulf  

Science Journals Connector (OSTI)

Salinity is an important component of the marine system. Due to shallow nature of the Persian Gulf, the salinity has been influenced by both wind driven and surface thermohaline fluxes (heat and moisture fluxes). In this study, the seasonal distribution of salinity and its variations due to wind stress and thermohaline forcing are investigated by using a three-dimensional hydrodynamic model, Coupled Hydrodynamical–Ecological Model for Regional and Shelf Seas (COHERENS). The simulation results show that the salinity in the Persian Gulf experiences dramatic spatial and temporal variations. The influence of the thermohaline forcing is considerably more than the wind stress on the salinity. The effect of the surface thermohaline fluxes over the salinity field is generally to increase the salinity for almost all the water column during the year. This effect is high during September–November where the evaporative surface salinity flux dominates over inflow of low-salinity values of Indian Ocean Surface Water. The wind forcing at the most regions of the Persian Gulf, in particular at the United Arab Emirate (UAE) coast and Bahrain–Qatar shelf, freshens the water all the year round. The wind and thermohaline forcing in March–June have strong potential to generate stratification in salinity structure. The model predictions, which are successful in simulating many features of observed pattern, indicate that the surface water of the Gulf is saltier in winter than that in spring and early summer. Both heat fluxes and wind stress play an important role for this seasonal cycle of the surface salinity.

S. Hassanzadeh; F. Hosseinibalam; A. Rezaei-Latifi

2011-01-01T23:59:59.000Z

382

Safety, Dependability and Performance Analysis of Extended AADL Models  

Science Journals Connector (OSTI)

......analysis Failure mode and effects analysis (FMEA) and fault tree analysis (FTA), model...Wesupporttwopopularhazardanalysistechniques:FMEA and FTA. Both techniques are realized...symbolic model checking [33, 34]. (i) FMEA is an inductive technique that starts by......

Marco Bozzano; Alessandro Cimatti; Joost-Pieter Katoen; Viet Yen Nguyen; Thomas Noll; Marco Roveri

2011-05-01T23:59:59.000Z

383

Performance and Portability of an Air Quality Model Donald Dabdub  

E-Print Network (OSTI)

and planning for the control of air pollution episodes. The California Institute of Technology (CIT) photochemical model is one such air quality model. It is used to predict the pollution dynamics in the South Coast Air Basin of California. It has also been modified to model pollution in South Korea, Mexico

Manohar, Rajit

384

Modeling and numerical analysis of the bond behavior of masonry elements strengthened with SRP/SRG  

Science Journals Connector (OSTI)

Abstract Steel Reinforced Polymers (SRPs) and Steel Reinforced Grout (SRG) strengthening systems have been recently introduced as an alternative solution to the traditional systems based on the use of fiber reinforced polymers materials (FRPs). Few studies on SRP/SRG are available in the current literature and all have shown the potentialities of SRP/SRG in improving structural performances of masonry and concrete elements and, at the same time, their difference with respect to \\{FRPs\\} particularly in terms of bond behavior. Aim of the present paper is to propose a simple approach devoted to study the bond behavior of masonry structures strengthened with SRP/SRG systems. The approach, based on experimental evidences and theoretical considerations mainly consists of deriving approximate bond stress-slip laws for the strengthening/support interface layer, able to reproduce the local bond stresses transferring mechanism. Finite Element (FE) analyses are then developed with reference to the experimental tests available in the current literature by adopting the bond stress-slip laws obtained through the proposed approach. The deduced results show the reliability of the proposed approach in simulating the bond behavior of masonry elements strengthened with SRP/SRG and the possibility to investigate further peculiarities characterizing this kind of strengthening systems.

Ernesto Grande; Maura Imbimbo; Elio Sacco

2013-01-01T23:59:59.000Z

385

BLACK-BOX MODELLING OF HVAC SYSTEM: IMPROVING THE PERFORMANCES OF NEURAL NETWORKS  

E-Print Network (OSTI)

BLACK-BOX MODELLING OF HVAC SYSTEM: IMPROVING THE PERFORMANCES OF NEURAL NETWORKS Eric FOCK Ile de La Réunion - FRANCE ABSTRACT This paper deals with neural networks modelling of HVAC systems of HVAC system can be modelled using manufacturer design data presented as derived performance maps

Boyer, Edmond

386

VALIDATION OF PV PERFORMANCE MODELS USING SATELLITE-BASED IRRADIANCE MEASUREMENTS: A CASE STUDY  

E-Print Network (OSTI)

performance model results are affected when satellite- based weather data is used in place of ground from a relatively small number of locations. In contrast, satellite-based radiation and weather data (e performance models using both ground and satellite-based weather inputs and compare model results

Perez, Richard R.

387

Improving Face Recognition Performance Using a Hierarchical Bayesian Model  

E-Print Network (OSTI)

which can result in an improved recognition performance over already existing baseline approaches. We use Kernelized Fisher Discriminant Analysis (KFLD) as our baseline as it is superior to PCA in a way that it produces well separated classes even under...

Shikaripur Nadig, Ashwini

2010-04-27T23:59:59.000Z

388

Accelerating Energy Savings Performance Contracting Through Model Statewide Programs  

Energy.gov (U.S. Department of Energy (DOE))

Provides information on Energy Savings Performance Contracing (ESPC), including links to best practices and tools as well as the Accelerated ESCP initiative and types of assistance available. Author: Energy Services Coalition

389

Case Studies Comparing System Advisor Model (SAM) Results to Real Performance Data: Preprint  

SciTech Connect

NREL has completed a series of detailed case studies comparing the simulations of the System Advisor Model (SAM) and measured performance data or published performance expectations. These case studies compare PV measured performance data with simulated performance data using appropriate weather data. The measured data sets were primarily taken from NREL onsite PV systems and weather monitoring stations.

Blair, N.; Dobos, A.; Sather, N.

2012-06-01T23:59:59.000Z

390

Methodology for Modeling Building Energy Performance across the Commercial Sector  

SciTech Connect

This report uses EnergyPlus simulations of each building in the 2003 Commercial Buildings Energy Consumption Survey (CBECS) to document and demonstrate bottom-up methods of modeling the entire U.S. commercial buildings sector (EIA 2006). The ability to use a whole-building simulation tool to model the entire sector is of interest because the energy models enable us to answer subsequent 'what-if' questions that involve technologies and practices related to energy. This report documents how the whole-building models were generated from the building characteristics in 2003 CBECS and compares the simulation results to the survey data for energy use.

Griffith, B.; Long, N.; Torcellini, P.; Judkoff, R.; Crawley, D.; Ryan, J.

2008-03-01T23:59:59.000Z

391

Advanced Fuel Performance: Modeling and Simulation Light Water...  

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

models, and will be designed for implementa- tion not only on today's leadership- class computers, but also for advanced architecture platforms now under de- velopment by DOE, as...

392

Carbon monoxide in the solar atmosphere I. Numerical method and two-dimensional models  

E-Print Network (OSTI)

The radiation hydrodynamic code CO5BOLD has been supplemented with the time-dependent treatment of chemical reaction networks. Advection of particle densities due to the hydrodynamic flow field is also included. The radiative transfer is treated frequency-independently, i.e. grey, so far. The upgraded code has been applied to two-dimensional simulations of carbon monoxide (CO) in the non-magnetic solar photosphere and low chromosphere. For this purpose a reaction network has been constructed, taking into account the reactions which are most important for the formation and dissociation of CO under the physical conditions of the solar atmosphere. The network has been strongly reduced to 27 reactions, involving the chemical species H, H2, C, O, CO, CH, OH, and a representative metal. The resulting CO number density is highest in the cool regions of the reversed granulation pattern at mid-photospheric heights and decreases strongly above. There, the CO abundance stays close to a value of 8.3 on the usual logarithmic abundance scale with [H]=12 but is reduced in hot shock waves which are a ubiquitous phenomenon of the model atmosphere. For comparison, the corresponding equilibrium densities have been calculated, based on the reaction network but also under assumption of instantaneous chemical equilibrium by applying the Rybicki & Hummer (RH) code by Uitenbroek (2001). Owing to the short chemical timescales, the assumption holds for a large fraction of the atmosphere, in particular the photosphere. In contrast, the CO number density deviates strongly from the corresponding equilibrium value in the vicinity of chromospheric shock waves. Simulations with altered reaction network clearly show that the formation channel via hydroxide (OH) is the most important one under the conditions of the solar atmosphere.

S. Wedemeyer-Boehm; I. Kamp; J. Bruls; B. Freytag

2005-03-23T23:59:59.000Z

393

Optimization of numerical weather/wave prediction models based on information geometry and computational techniques  

Science Journals Connector (OSTI)

The last years a new highly demanding framework has been set for environmental sciences and applied mathematics as a result of the needs posed by issues that are of interest not only of the scientific community but of today's society in general: global warming renewable resources of energy natural hazards can be listed among them. Two are the main directions that the research community follows today in order to address the above problems: The utilization of environmental observations obtained from in situ or remote sensing sources and the meteorological-oceanographic simulations based on physical-mathematical models. In particular trying to reach credible local forecasts the two previous data sources are combined by algorithms that are essentially based on optimization processes. The conventional approaches in this framework usually neglect the topological-geometrical properties of the space of the data under study by adopting least square methods based on classical Euclidean geometry tools. In the present work new optimization techniques are discussed making use of methodologies from a rapidly advancing branch of applied Mathematics the Information Geometry. The latter prove that the distributions of data sets are elements of non-Euclidean structures in which the underlying geometry may differ significantly from the classical one. Geometrical entities like Riemannian metrics distances curvature and affine connections are utilized in order to define the optimum distributions fitting to the environmental data at specific areas and to form differential systems that describes the optimization procedures. The methodology proposed is clarified by an application for wind speed forecasts in the Kefaloniaisland Greece.

2014-01-01T23:59:59.000Z

394

An integrated performance model for high temperature gas cooled reactor coated particle fuel  

E-Print Network (OSTI)

The performance of coated fuel particles is essential for the development and deployment of High Temperature Gas Reactor (HTGR) systems for future power generation. Fuel performance modeling is indispensable for understanding ...

Wang, Jing, 1976-

2004-01-01T23:59:59.000Z

395

Cooperative Energy Efficiency Modeling and Performance Analysis in Co-Channel Interference Cellular Networks  

Science Journals Connector (OSTI)

......Communications Cooperative Energy Efficiency Modeling and Performance...cooperative communications, energy efficiency is becoming increasingly...but also the green-house gas emission and carbon...most cases, high energy efficiency performance should......

Jing Zhang; Xi Yang; Qi Yao; Xiaohu Ge; Minho Jo; Guoqiang Mao

2013-08-01T23:59:59.000Z

396

Performance Modeling and Simulation Studies of MAC Protocols in Sensor Network Performance  

E-Print Network (OSTI)

tree R used for performance evaluation. II. ENERGY EFFICIENT WAKE-UP AND DATA COLLECTION Data Sahota Ratnesh Kumar Ahmed Kamal Dept. of Electrical and Computer Engineering, Iowa State University for the purpose of achieving energy savings. In addition, MAC layer is designed which uses these multiple power

Kumar, Ratnesh

397

A NEW MODEL FOR PERFORMANCE PREDICTION OF HARD ROCK TBMS.  

E-Print Network (OSTI)

methods to accu- rately predict the penetration rate of a TBM in a given geology. These models are mainly, and the penetration rate. A good example of this is the Norwegian (NTH) hard rock diagnostic system and predictor penetration rate. This group of models 1.ResearchAssociakandGraduacStudentinMiningErrg.Dept. 2.Directorof

398

Runtime Performance Modeling and Measurement of Adaptive Distributed Object Applications  

Science Journals Connector (OSTI)

Distributed applications that can adapt at runtime to changing quality of service (QoS) require a model of the expected QoS and of the possible application adaptations. QoS models in turn require runtime measurements, both in-band and out-of-band, from ...

John A. Zinky; Joseph P. Loyall; Richard Shapiro

2002-10-01T23:59:59.000Z

399

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

SciTech Connect

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

Malapaka, Shiva Kumar; Mueller, Wolf-Christian [Max-Planck Institute for Plasma Physics, Boltzmannstrasse 2, D-85748 Garching bei Muenchen (Germany)

2013-09-01T23:59:59.000Z

400

ON THE IMPACT OF SUPER RESOLUTION WSR-88D DOPPLER RADAR DATA ASSIMILATION ON HIGH RESOLUTION NUMERICAL MODEL FORECASTS  

SciTech Connect

Assimilation of radar velocity and precipitation fields into high-resolution model simulations can improve precipitation forecasts with decreased 'spin-up' time and improve short-term simulation of boundary layer winds (Benjamin, 2004 & 2007; Xiao, 2008) which is critical to improving plume transport forecasts. Accurate description of wind and turbulence fields is essential to useful atmospheric transport and dispersion results, and any improvement in the accuracy of these fields will make consequence assessment more valuable during both routine operation as well as potential emergency situations. During 2008, the United States National Weather Service (NWS) radars implemented a significant upgrade which increased the real-time level II data resolution to 8 times their previous 'legacy' resolution, from 1 km range gate and 1.0 degree azimuthal resolution to 'super resolution' 250 m range gate and 0.5 degree azimuthal resolution (Fig 1). These radar observations provide reflectivity, velocity and returned power spectra measurements at a range of up to 300 km (460 km for reflectivity) at a frequency of 4-5 minutes and yield up to 13.5 million point observations per level in super-resolution mode. The migration of National Weather Service (NWS) WSR-88D radars to super resolution is expected to improve warning lead times by detecting small scale features sooner with increased reliability; however, current operational mesoscale model domains utilize grid spacing several times larger than the legacy data resolution, and therefore the added resolution of radar data is not fully exploited. The assimilation of super resolution reflectivity and velocity data into high resolution numerical weather model forecasts where grid spacing is comparable to the radar data resolution is investigated here to determine the impact of the improved data resolution on model predictions.

Chiswell, S

2009-01-11T23:59:59.000Z

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


401

Improvement of Electrocatalyst Performance in Hydrogen Fuel Cells by Multiscale Modelling.  

E-Print Network (OSTI)

??The work in this thesis addresses the improvement of electrocatalyst performance inhydrogen PEM fuel cells. An agglomerate model for a catalyst layer was coupled witha… (more)

Marthosa, Sutida

2012-01-01T23:59:59.000Z

402

Wind resource assessment using numerical weather prediction models and multi-criteria decision making technique: case study (Masirah Island, Oman)  

Science Journals Connector (OSTI)

The Authority for Electricity Regulation in Oman has recently announced the implementation of a 500 kW wind farm pilot project in Masirah Island. Detailed wind resource assessment is then required to identify the most suitable location for this project. This paper presents wind resource assessment using nested ensemble numerical weather prediction (NWP) model's approach at 2.8 km resolution and multi-criteria decision making (MCDM) technique. A case study based on the proposed approach is conducted over Masirah Island, Oman. The resource assessment over the island was based on the mean wind speed and wind power distribution over the entire island at different heights. In addition, important criteria such as turbulence intensity and peak hour matching are also considered. The NWP model results were verified against the available 10 m wind data observations from the meteorological station in the northern part of the island. The resource assessment criteria were evaluated using MCDM technique to score the locations over the island based on their suitability for wind energy applications. Two MCDM approaches namely equally weighted and differently weighted criteria were implemented in this paper.

Sultan Al-Yahyai; Yassine Charabi; Abdullah Al-Badi; Adel Gastli

2013-01-01T23:59:59.000Z

403

Modeling the Performance of Engineered Systems for Closure and Near-Surface Disposal  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

performance cleanup closure performance cleanup closure M E Environmental Management Environmental Management Performance Assessment Community of Practice Technical Exchange July 13-14, 2009 Modeling the Performance of Engineered Systems for Closure and Near-Surface Disposal - Overview and Focused Discussions David S. Kosson CRESP and Vanderbilt University Tank Waste Corporate Board Meeting July 29, 2009 1 safety performance cleanup closure M E Environmental Management Environmental Management Agenda * Overview of DOE Performance Assessment Practices * Focused Discussions - Role of PA Process in Risk Communication and Decisions - Modeling Improvements - PA Assumption Validation - Uncertainty Evaluation - Evolving EPA Developments - Related IAEA Activities * Looking forward

404

A Comparison of HCCI Engine Performance Data and Kinetic Modeling...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

- Better chance to predict emissions CFD model - Most true to flow, mixing, and heat loss processes 5 Managed by UT-Battelle for the Department of Energy ORNL HCCI engine...

405

Hybrid Model for Building Performance Diagnosis and Optimal Control  

E-Print Network (OSTI)

and two capacitances, is used to simulate building envelope whose parameters are determined in frequency domain using the theoretical frequency characteristics of the envelope. Internal mass is represented by a 2R2C thermal network model, which consists...

Wang, S.; Xu, X.

2003-01-01T23:59:59.000Z

406

Modeling maintenance projects risk effects on ERP performance  

Science Journals Connector (OSTI)

Worldwide organizations have made important efforts to replace their legacy information applications by ERP (Enterprise Resource Planning) solutions. However, a suitable system implementation does not guarantee the ERP adoption success. This also depends ... Keywords: ERP maintenance, Simulations, Soft computing, Software project risks, System performance

Cristina López; Jose L. Salmeron

2014-03-01T23:59:59.000Z

407

Model Energy Savings Performance Contract, Schedules, and Exhibits  

Energy.gov (U.S. Department of Energy (DOE))

The Energy Savings Performance Contract defines the project, establishing how it will be implemented during construction and how it will be managed through the entire term of the agreement, addressing construction details, roles and responsibilities of the ESCO and Institution, and guaranteed savings through measurement and verification.

408

Numerical Analyses of CERN 200GeV/A Heavy-Ion Collisions Based on a Hydrodynamical Model with Phase Transition  

E-Print Network (OSTI)

We numerically analyze recent high energy heavy-ion collision experiments based on a hydrodynamical model with phase transition and discuss a systematic change of initial state of QGP-fluid depending on colliding-nuclei's mass. In a previous paper, we formulated a (3+1)-dimensional hydrodynamical model for quark-gluon plasma with phase transition and discussed numerically the space-time evolution in detail. We here compare the numerical solution with the hadronic distributions given by CERN WA80 and NA35. Systematic analyses of the experiments with various colliding nuclei enable us to discuss the dependences of the initial parameters of the hydrodynamical model on colliding nuclei's mass. Furthermore, extrapolating the present experiments, we derive the possible hadronic distributions for lead-lead 150GeV/A collision.

Shin Muroya; Hiroki Nakamura; Mikio Namiki

1995-02-02T23:59:59.000Z

409

Hybrid Model of Existing Buildings for Transient Thermal Performance Estimation  

E-Print Network (OSTI)

. The model parameters, Cim,1, Rim,1, Cim,2, Rim,2, of the building internal mass can be optimized by minimizing the difference between the measured cooling energy consumption and the model predicted ICEBO2006, Shenzhen, China Control Systems... parameters (Cim,1, Rim,1, Cim,2, Rim,2) constitute the chromosome of an individual, the assumed ranges of these parameters are the search space for these parameters. Initializing the four parameters produces the initial population to start a GA run...

Xu, X.; Wang, S.

2006-01-01T23:59:59.000Z

410

Modeling the Impact of Product Portfolio on the Economic and Environmental Performance of Recycling Systems  

E-Print Network (OSTI)

hrough the development of a general model of electronics recycling systems, the effect of product portfolio choices on economic and environmental system performance is explored. The general model encompasses the three main ...

Dahmus, Jeffrey B.

411

Numerical Modelling of Oxy-Fuel Combustion in a Full-Scale Tangentially-Fired Pulverised Coal Boiler  

Science Journals Connector (OSTI)

Abstract This paper presents a computational fluid dynamics (CFD) modelling study to investigate Victorian brown coal combustion in a 550 MW utility boiler under the air-fired (standard) and three oxy-fuel-fired cases. The standard case was modelled based on the real operating conditions of Loy Yang A power plant located in the state of Victoria, Australia. A level of confidence of the present CFD model was achieved validating four parameters of the standard combustion case, as well as the previous preliminary CFD studies which were conducted on a lab-scale (100 kW) unit firing lignite and propane under oxy-fuel-fired scenarios. The oxy-fuel combustion cases are known as OF25 (25vol. % O2 concentration), OF27 (27vol. % O2 concentration), and OF29 (29vol. % O2 concentration). The predictions of OF29 combustion case were considerably similar to the standard firing results in terms of gas temperature levels and radiative heat transfer compared with OF25 and OF27 combustion scenarios. This similarity was because of increasing the residence time of pulverised coal (PC) in the combustion zone and O2 concentration in feed oxidizer gases. Furthermore, a significant increase in the CO2 concentrations and a noticeable decrease in the nitric oxides (NOx) formation were noted under all oxy-fuel combustion conditions. This numerical study of oxy-fuel combustion in a full-scale tangentially-fired PC boiler is important prior to its execution in real-life power plants.

Audai Hussein Al-Abbas; Jamal Naser; David Dodds; Aaron Blicblau

2013-01-01T23:59:59.000Z

412

Abstract--Eventually, prediction of transformer thermal performance for dynamic loading will be made using models  

E-Print Network (OSTI)

1 Abstract--Eventually, prediction of transformer thermal performance for dynamic loading will be made using models distilled from measure data, rather than models derived from transformer heat for measuring the acceptability of transformer thermal models. For a model to be acceptable, it must have

413

18 Modeling high-performance HBTs D.L. Pulfrey  

E-Print Network (OSTI)

an acceptable base resistance. A short base width leads directly to an improved cut-off frequency, fT , which, when coupled with the lower base resistance, leads to an improved oscillation frequency, fmax. These consideration is also given to the incorporation of the compact model for JC into a large-signal equivalent

Pulfrey, David L.

414

Duct Thermal Performance Models for Large Commercial Buildings  

E-Print Network (OSTI)

Energy Technologies Division Indoor Environment Department Lawrence Berkeley National Laboratory Berkeley Secretary for Energy Efficiency and Renewable Energy, Building Technologies Program, of the U.S. Department) for his assistance in defining the duct surface heat transfer models described in the body of this report

415

Analytic Models of Workload Behavior and Pipeline Performance Mark S. Squillante  

E-Print Network (OSTI)

Analytic Models of Workload Behavior and Pipeline Performance Mark S. Squillante IBM Research,sinhag@ece.neu.edu Abstract The evaluation of pipeline performance and the analysis of different design alternatives and cost process requires accurate models of both the pipeline or­ ganization and the characteristics

Kaeli, David R.

416

Probabilistic Modeling and Evaluation of the Performance, Emissions, and Cost of Texaco Gasifier-  

E-Print Network (OSTI)

Probabilistic Modeling and Evaluation of the Performance, Emissions, and Cost of Texaco Gasifier.0 DOCUMENTATION OF THE PLANT PERFORMANCE SIMULATION MODEL IN ASPEN OF THE COAL-FUELED TEXACO-GASIFIER BASED IGCC to the Gasifier............................... 40 3.2.2 Gasification

Frey, H. Christopher

417

MODELING THE EFFECT OF FLOW FIELD DESIGN ON PEM FUEL CELL PERFORMANCE  

E-Print Network (OSTI)

MODELING THE EFFECT OF FLOW FIELD DESIGN ON PEM FUEL CELL PERFORMANCE Jeffrey Glandt, Sirivatch University of South Carolina Columbia, SC 29208 vanzee@engr.sc.edu Key words: PEM fuel cell, flow field or printed in its publications. #12;2 MODELING THE EFFECT OF FLOW FIELD DESIGN ON PEM FUEL CELL PERFORMANCE

Van Zee, John W.

418

Guilt-based handling of software performance antipatterns in palladio architectural models  

Science Journals Connector (OSTI)

Antipatterns are conceptually similar to patterns in that they document recurring solutions to common design problems. Software performance antipatterns document common performance problems in the design as well as their solutions. The definition of ... Keywords: Architectural feedback, Palladio architectural models, Software performance antipatterns

Catia Trubiani, Anne Koziolek, Vittorio Cortellessa, Ralf Reussner

2014-09-01T23:59:59.000Z

419

Modeling the Logistics Performance in Developing Countries: An exploratory study of Moroccan context  

E-Print Network (OSTI)

1 Modeling the Logistics Performance in Developing Countries: An exploratory study of Moroccan to raise their levels of logistics performance. This article is a research progress; it presents, Technological Practices, Supply Chain performance, Morocco. 1. INTRODUCTION: Logistic in Morocco is still

Paris-Sud XI, Université de

420

Seismic performance of polymer modified concretes in flexure-modelling  

Science Journals Connector (OSTI)

Considerable research has been carried out in the recent years in the development of models to simulate the inelastic responses of reinforced concrete elements. The enhancement of ductility and the post-peak behaviour are of special interest for the seismic design of structures. Polymer modified fibre concretes are found to be ideal for seismic application with its inherent structural characteristics. An experimental investigation has been undertaken to understand the flexural behaviour of the polymer-modified fibre concrete modified with natural rubber latex. The results are compared with the response of normal strength concrete beam. Analytical modelling of the beams were carried out in a user friendly finite element software to accurately predict the monotonic behaviour of the beams which is considered to be the envelope of cyclic curve. The strains developed were found and are compared with the theoretical results.

R. Sreekala; K. Muthumani; N. Gopalakrishnan; K. Sathish Kumar; G.V. Rama Rao; Nagesh R. Iyer

2012-01-01T23:59:59.000Z

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


421

A Linear Parabolic Trough Solar Collector Performance Model  

E-Print Network (OSTI)

: 1 bar (winter) Pressure in solar collection loop: 10 bar (Summer), 5 bar (winter) Pressure in main chilled water loop : 1 bar (summer) TIC TIC TIC TIC Space Thermostat May 18,06 Parabolic Solar Trough Collector: 52.44 m^2 / 4 modules... & winter) Chilled/Heat Water Storage Current Existing Future Installation Current Installation TIC TIC EIC Temperature indicator controller Energy indicator controller Fig. 1 IW solar heating and cooling system 1.3 EES Model In order to understand...

Qu, M.; Archer, D.; Masson, S.

2006-01-01T23:59:59.000Z

422

Sensitivity of Concentrating Solar Power Trough Performance, Cost and Financing with Solar Advisor Model  

SciTech Connect

A comprehensive solar technology systems analysis model, the Solar Advisor Model (SAM) was developed to support the federal R&D community and the solar industry. This model, developed by staff at NREL and Sandia National Laboratory, is able to model the costs, finances, and performance of concentrating solar power and photovoltaics (PV). Currently, parabolic troughs and concentrating PV are the two concentrating technologies modeled within the SAM environment.

Blair, N.; Mehos, M.; Christensen, C.

2008-03-01T23:59:59.000Z

423

Numerical studies of the high power microwave breakdown in gas using the fluid model with a modified electron energy distribution function  

SciTech Connect

A modified electron energy distribution function (EEDF) is introduced into the fluid model and its effects on the high power microwave (HPM) breakdown in air and argon are investigated. A proper numerical scheme for the finite-difference time-domain method is employed to solve the fluid model. Numerical simulations show that the HPM breakdown time in argon predicted by the fluid model with the modified EEDF agrees well with the results of Particle-in-cell-Monte Carlo collision simulations, while the Maxwellian EEDF results in faster HPM breakdown when the mean electron energy is less than 20 eV. We also confirm that the Maxwellian EEDF can be used in the fluid model for simulating the air breakdown at the low frequencies based on the reported experiments.

Zhao Pengcheng; Liao Cheng; Lin Chenbin; Chang Lei; Fu Haijun [Institute of Electromagnetics, Southwest Jiaotong University, Chengdu 610031 (China)

2011-10-15T23:59:59.000Z

424

Modeling Photovoltaic and Concentrating Solar Power Trough Performance, Cost, and Financing with the Solar Advisor Model: Preprint  

SciTech Connect

A comprehensive solar technology systems analysis model, the Solar Advisor Model (SAM), has been developed to support the federal R&D community and the solar industry by staff at the National Renewable Energy Laboratory (NREL) and Sandia National Laboratory. This model is able to model the finances, incentives, and performance of flat-plate photovoltaic (PV), concentrating PV, and concentrating solar power (specifically, parabolic troughs). The primary function of the model is to allow users to investigate the impact of variations in performance, cost, and financial parameters to better understand their impact on key figures of merit. Figures of merit related to the cost and performance of these systems include, but aren't limited to, system output, system efficiencies, levelized cost of energy, return on investment, and system capital and O&M costs. There are several models within SAM to model the performance of photovoltaic modules and inverters. This paper presents an overview of each PV and inverter model, introduces a new generic model, and briefly discusses the concentrating solar power (CSP) parabolic trough model. A comparison of results using the different PV and inverter models is also presented.

Blair, N.; Mehos, M.; Christensen, C.; Cameron, C.

2008-05-01T23:59:59.000Z

425

Accounting for the effects of rehabilitation actions on the reliability of flexible pavements: performance modeling and optimization  

E-Print Network (OSTI)

A performance model and a reliability-based optimization model for flexible pavements that accounts for the effects of rehabilitation actions are developed. The developed performance model can be effectively implemented in all the applications...

Deshpande, Vighnesh Prakash

2009-05-15T23:59:59.000Z

426

Results and Comparison from the SAM Linear Fresnel Technology Performance Model: Preprint  

SciTech Connect

This paper presents the new Linear Fresnel technology performance model in NREL's System Advisor Model. The model predicts the financial and technical performance of direct-steam-generation Linear Fresnel power plants, and can be used to analyze a range of system configurations. This paper presents a brief discussion of the model formulation and motivation, and provides extensive discussion of the model performance and financial results. The Linear Fresnel technology is also compared to other concentrating solar power technologies in both qualitative and quantitative measures. The Linear Fresnel model - developed in conjunction with the Electric Power Research Institute - provides users with the ability to model a variety of solar field layouts, fossil backup configurations, thermal receiver designs, and steam generation conditions. This flexibility aims to encompass current market solutions for the DSG Linear Fresnel technology, which is seeing increasing exposure in fossil plant augmentation and stand-alone power generation applications.

Wagner, M. J.

2012-04-01T23:59:59.000Z

427

Development of a housing performance evaluation model for multi-family residential buildings in Korea  

Science Journals Connector (OSTI)

This paper presents the development and application of a housing performance evaluation model for multi-family residential buildings in Korea. This model is intended to encourage initiatives toward achieving better housing performance and to support a homebuyer's decision-making on housing comparison and selection. Forty-one objective and feasible housing performance indicators, which were selected from the review of existing evaluation models and interviews with experts, are classified into a series of categories. The weights of each category and indicator are calculated by using the analytic hierarchy process (AHP) analysis, and a weight is converted into credit. Next, the performance grades are divided into four levels, and evaluation criteria are suggested based on statutory performance value or the one frequently met in practice. Finally, the evaluation program and the application procedure are established through the field case study. This model can be used for objective and practical evaluation and comparison of residential housing alternatives.

Sun-Sook Kim; In-Ho Yang; Myoung-Souk Yeo; Kwang-Woo Kim

2005-01-01T23:59:59.000Z

428

Validated Model-Based Performance Prediction of Multi-Core Software Routers  

E-Print Network (OSTI)

Terms--measurement, simulation, intra-node model, re- source contention, model validation, software components. Leveraged by high flexibility and low costs of software developments in comparison with hardwareValidated Model-Based Performance Prediction of Multi-Core Software Routers Torsten Meyer1

Carle, Georg

429

Analytical Model for RF Power Performance of Deeply Scaled CMOS Devices  

E-Print Network (OSTI)

predictions from the model with measured load-pull data on 45 nm CMOS devices. II. MODEL DESCRIPTION The power by the load resistor. Fig. 1: Circuit diagram of a reduced conduction angle RF power amplifier. Fig. 2Analytical Model for RF Power Performance of Deeply Scaled CMOS Devices Usha Gogineni1 , Jesús del

del Alamo, Jesús A.

430

A Simulation Model for the Performance Evaluation for Migrating a Legacy Paulo Pinheiro da Silva  

E-Print Network (OSTI)

A Simulation Model for the Performance Evaluation for Migrating a Legacy System Paulo Pinheiro da a simulation model using CAPPLES. Peculiarities of the legacy system migration that affects the simulation of perfor- mance evaluation during migration. CAPPLES is based on simulation models. Indeed, analytical

Pinheiro da Silva, Paulo

431

Smart Grid Cybersecurity: Job Performance Model Report and Phase 1 Overview  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Cybersecurity: Job Performance Model Report and Phase 1 Cybersecurity: Job Performance Model Report and Phase 1 Overview (August 2012) Smart Grid Cybersecurity: Job Performance Model Report and Phase 1 Overview (August 2012) In the spring of 2011, the U.S. Department of Energy awarded a project to Pacific Northwest National Laboratory in partnership with the National Board of Information Security Examiners to develop a set of guidelines to enhance development of the smart grid cybersecurity workforce and provide a foundation for future certifications. The project has three phases. The first phase produced an exploratory Job Performance Model based on a factor analysis of responses to a multi-page survey, the Job Analysis Questionnaire (JAQ). The second phase of the project will seek to validate the exploratory model in laboratory simulation studies of a small group of

432

Discrimination between 1/f noise models in junctions field effect transistors and metal?oxide?semiconductor field effect transistors: Numerical results  

Science Journals Connector (OSTI)

The integrals given by Park e t a l. in an earlier paper [J. Appl. Phys. 52 296 (1981)] on 1/f noise are expressed in closed forms and evaluated numerically. The results show how the field dependent mobility affects the number fluctuation model and how the field dependent mobility and the field dependence of Hooge’s parameter ? affects the mobility fluctuation model. The latter effect is very strong and results in a large decrease in the noise spectrum at larger values of drain bias when compared with the elementary theory that neglects these field dependences. For relatively short channels the mobility fluctuation model gives a peak in the noise well before saturation in agreement with the experiments of Park e t a l. The effects of the field dependent mobility and of the field dependent ? on the noise resistance at saturation are evaluated numerically.

A. van der Ziel; R. J. J. Zijlstra; H. S. Park

1981-01-01T23:59:59.000Z

433

Integrated cluster analysis and artificial neural network modeling for steam-assisted gravity drainage performance prediction in heterogeneous reservoirs  

Science Journals Connector (OSTI)

Abstract Evaluation of steam-assisted gravity drainage (SAGD) performance that involves detailed compositional simulations is usually deterministic, cumbersome, expensive (manpower and time consuming), and not quite suitable for practical decision making and forecasting, particularly when dealing with high-dimensional data space consisting of large number of operational and geological parameters. Data-driven modeling techniques, which entail comprehensive data analysis and implementation of machine learning methods for system forecast, provide an attractive alternative. In this paper, artificial neural network (ANN) is employed to predict SAGD production in heterogeneous reservoirs, an important application that is lacking in existing literature. Numerical flow simulations are performed to construct a training data set consists of various attributes describing characteristics associated with reservoir heterogeneities and other relevant operating parameters. Empirical Arps decline parameters are tested successfully for parameterization of cumulative production profile and considered as outputs of the ANN models. Sensitivity studies on network configurations are also investigated. Principal components analysis (PCA) is performed to reduce the dimensionality of the input vector, improve prediction quality, and limit over-fitting. In a case study, reservoirs with distinct heterogeneity distributions are fed to the model. It is shown that robustness and accuracy of the prediction capability are greatly enhanced when cluster analysis are performed to identify internal data structures and groupings prior to ANN modeling. Both deterministic and fuzzy-based clustering techniques are compared, and separate ANN model is constructed for each cluster. The model is then tested using a validation data set (cases that have not been used during the training stage). The proposed approach can be integrated directly into most existing reservoir management routines. In addition, incorporating techniques for dimensionality reduction and clustering with ANN demonstrates the viability of this approach for analyzing large field data set. Given that quantitative ranking of operating areas, robust forecasting, and optimization of heavy oil recovery processes are major challenges faced by the industry, the proposed research highlights the significant potential of applying effective data-driven modeling approaches in analyzing other solvent-additive steam injection projects.

Ehsan Amirian; Juliana Y. Leung; Stefan Zanon; Peter Dzurman

2015-01-01T23:59:59.000Z

434

Evaluation of numerical weather prediction for intra-day solar forecasting in the continental United States  

E-Print Network (OSTI)

for numerical weather prediction and climate models.   Abstract:  Numerical weather prediction (NWP) models are Model output statistics (MOS), Numerical Weather Prediction (

Mathiesen, Patrick; Kleissl, Jan

2011-01-01T23:59:59.000Z

435

The use of numerical models in support of site characterization and performance assessment studies for geological repositories  

E-Print Network (OSTI)

Research Contracts (work programme linked to limited funding) to the following countries and institutions: Brazil (BRA); Centro de Desenvolvimento da Tecnologia Nuclear (

Neerdael, B.

2011-01-01T23:59:59.000Z

436

Dynamic modeling and performance of the first cell of a multi-effect distillation plant  

Science Journals Connector (OSTI)

Abstract This paper describes a model to simulate the thermal transient behavior of the first cell of a solar-assisted multi-effect distillation (MED) plant. It has been designed according to the experience with an experimental solar thermal desalination system erected at CIEMAT-Plataforma Solar de Almería (PSA). The non-linear first principles model has been developed using the object-oriented Modelica language. It includes two submodels corresponding to the effect and the preheater of the first cell of the MED plant. Both submodels have been calibrated and validated with experimental data. The numerical predictions show a good agreement with measured data.

Alberto de la Calle; Javier Bonilla; Lidia Roca; Patricia Palenzuela

2014-01-01T23:59:59.000Z

437

Thermal mass performance in residential construction : an energy analysis using a cube model  

E-Print Network (OSTI)

Given the pervasiveness of energy efficiency concerns in the built environment, this research aims to answer key questions regarding the performance of thermal mass construction. The work presents the Cube Model, a simplified ...

Ledwith, Alison C. (Alison Catherine)

2012-01-01T23:59:59.000Z

438

High-performance Earth system modeling with NASA/GSFC’s Land Information System  

Science Journals Connector (OSTI)

The Land Information System software (LIS; http://lis.gsfc.nasa.gov/, 2006) has been developed to support high-performance land surface modeling and data assimilation. LIS integrates parallel and distributed comp...

C. D. Peters-Lidard; P. R. Houser; Y. Tian…

2007-09-01T23:59:59.000Z

439

Structural Models and Endogeneity in Corporate Finance: The Link Between Managerial Ownership and Corporate Performance  

E-Print Network (OSTI)

This paper presents a parsimonious, structural model that isolates primary economic determinants of the level and dispersion of managerial ownership, firm scale, and performance and the empirical associations among them. ...

Coles, Jeffrey L.; Lemmon, Michael L.; Meschke, Felix

2012-01-01T23:59:59.000Z

440

Model studies to investigate the effects of fixed streamlines on water flooding performance  

E-Print Network (OSTI)

MODEL STUDIES TO INVESTIGATE THE EFFECTS OF FIXED STREAMLINES ON WATER FLOODING PERFORMANCE A Thesis by Axel Venton Green Submitted to the Graduate College of the Texas ASrM University in partial fulfillment of the requirements...

Green, Axel Venton

1964-01-01T23:59:59.000Z

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


441

Testing Linear Diagnostics of Ensemble Performance on a Simplified Global Circulation Model  

E-Print Network (OSTI)

Ensemble weather forecast systems are used to account for the uncertainty in the initial conditions of the atmosphere and the chaotic dynamics of the models. It has been previously found that forecast performance of an ensemble forecast system...

Nelson, Ethan

2011-04-21T23:59:59.000Z

442

Modeling of Performance, Cost, and Financing of Concentrating Solar, Photovoltaic, and Solar Heat Systems (Poster)  

SciTech Connect

This poster, submitted for the CU Energy Initiative/NREL Symposium on October 3, 2006 in Boulder, Colorado, discusses the modeling, performance, cost, and financing of concentrating solar, photovoltaic, and solar heat systems.

Blair, N.; Mehos, M.; Christiansen, C.

2006-10-03T23:59:59.000Z

443

Systems, methods and computer-readable media for modeling cell performance fade of rechargeable electrochemical devices  

DOE Patents (OSTI)

A system includes an electrochemical cell, monitoring hardware, and a computing system. The monitoring hardware periodically samples performance characteristics of the electrochemical cell. The computing system determines cell information from the performance characteristics of the electrochemical cell. The computing system also develops a mechanistic level model of the electrochemical cell to determine performance fade characteristics of the electrochemical cell and analyzing the mechanistic level model to estimate performance fade characteristics over aging of a similar electrochemical cell. The mechanistic level model uses first constant-current pulses applied to the electrochemical cell at a first aging period and at three or more current values bracketing a first exchange current density. The mechanistic level model also is based on second constant-current pulses applied to the electrochemical cell at a second aging period and at three or more current values bracketing the second exchange current density.

Gering, Kevin L

2013-08-27T23:59:59.000Z

444

Nonlinear time-domain performance model for a wave energy converter...  

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

Time-Domain Performance Model for a Wave Energy Converter in Three Dimensions Ryan G. Coe and Diana L. Bull Water Power Technologies Sandia National Labs Albuquerque, NM 87185-1124...

445

Simulation of heavy oil reservoir performance using a non-Newtonian flow model  

E-Print Network (OSTI)

SIMULATION OF HEAVY OIL RESERVOIR PERFORMANCE USING A NON-NEWTONIAN FLOW MODEL A Thesis by GENE MASAO NARAHARA Submitted to the Graduate College of Texas AILM University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE December 1983 Major Subject: Petroleum Engineering SIMULATION OF HEAVY OIL RESERVOIR PERFORMANCE USING A NON-NEWTONIAN FLOW MODEL A Thesis by GENE MASAO NARAHARA Approved as to style and content by: lng . U an of Committee) R. . Morse...

Narahara, Gene Masao

1983-01-01T23:59:59.000Z

446

Genetic icing effects on forward flight performance of a model helicopter rotor  

E-Print Network (OSTI)

GENERIC ICING EFFECTS ON FORWARD FLIGHT PERFORMANCE OF A MODEL HELICOPTER ROTOR A Thesis ANA FIORELLA TINETTI-SANCHEZ Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE December 1987 Major Subject: Aerospace Engineering GENERIC ICING EFFECTS ON FORWARD FLIGHT PERFORMANCE OF A MODEL HELICOPTER ROTOR A Thesis by ANA FIORELLA TINETTI-SANCHEZ Approved as to style and content by: Kenneth D. Korkan...

Tinetti-Sanchez, Ana Fiorella

2012-06-07T23:59:59.000Z

447

Numerical Modeling of Footpoint-driven Magneto-acoustic Wave Propagation in a Localized Solar Flux Tube  

Science Journals Connector (OSTI)

In this paper, we present and discuss results of two-dimensional simulations of linear and nonlinear magneto-acoustic wave propagation through an open magnetic flux tube embedded in the solar atmosphere expanding from the photosphere through to the transition region and into the low corona. Our aim is to model and analyze the response of such a magnetic structure to vertical and horizontal periodic motions originating in the photosphere. To carry out the simulations, we employed our MHD code SAC (Sheffield Advanced Code). A combination of the VALIIIC and McWhirter solar atmospheres and coronal density profiles were used as the background equilibrium model in the simulations. Vertical and horizontal harmonic sources, located at the footpoint region of the open magnetic flux tube, are incorporated in the calculations, to excite oscillations in the domain of interest. To perform the analysis we have constructed a series of time-distance diagrams of the vertical and perpendicular components of the velocity with respect to the magnetic field lines at each height of the computational domain. These time-distance diagrams are subject to spatio-temporal Fourier transforms allowing us to build ?-k dispersion diagrams for all of the simulated regions in the solar atmosphere. This approach makes it possible to compute the phase speeds of waves propagating throughout the various regions of the solar atmosphere model. We demonstrate the transformation of linear slow and fast magneto-acoustic wave modes into nonlinear ones, i.e., shock waves, and also show that magneto-acoustic waves with a range of frequencies efficiently leak through the transition region into the solar corona. It is found that the waves interact with the transition region and excite horizontally propagating surface waves along the transition region for both types of drivers. Finally, we estimate the phase speed of the oscillations in the solar corona and compare it with the phase speed derived from observations.

V. Fedun; S. Shelyag; R. Erdélyi

2011-01-01T23:59:59.000Z

448

Development of a High-Performance Office Building Simulation Model for a Hot and Humid Climate  

E-Print Network (OSTI)

to the field measured data and was presented in the previous publication (Cho and Haberl, 2008a). The calibrated simulation model was further extended to an ASHRAE 90.1 code-compliant model, which was used as the baseline model for the development of a... high-performance (energy-efficient) model. However, the code-compliant model did not use the as-built building geometry of the JBC building; rather, it used a simplified geometry. The simplified- geometry, code-compliant simulation model...

Cho, S.; Haberl, J.

449

Use of ARM observations and numerical models to determine radiative and latent heating profiles of mesoscale convective systems for general circulation models  

SciTech Connect

We examined cloud radar data in monsoon climates, using cloud radars at Darwin in the Australian monsoon, on a ship in the Bay of Bengal in the South Asian monsoon, and at Niamey in the West African monsoon. We followed on with a more in-depth study of the continental MCSs over West Africa. We investigated whether the West African anvil clouds connected with squall line MCSs passing over the Niamey ARM site could be simulated in a numerical model by comparing the observed anvil clouds to anvil structures generated by the Weather Research and Forecasting (WRF) mesoscale model at high resolution using six different ice-phase microphysical schemes. We carried out further simulations with a cloud-resolving model forced by sounding network budgets over the Niamey region and over the northern Australian region. We have devoted some of the effort of this project to examining how well satellite data can determine the global breadth of the anvil cloud measurements obtained at the ARM ground sites. We next considered whether satellite data could be objectively analyzed to so that their large global measurement sets can be systematically related to the ARM measurements. Further differences were detailed between the land and ocean MCS anvil clouds by examining the interior structure of the anvils with the satellite-detected the CloudSat Cloud Profiling Radar (CPR). The satellite survey of anvil clouds in the Indo-Pacific region was continued to determine the role of MCSs in producing the cloud pattern associated with the MJO.

Houze, Jr., Robert A. [University of Washington Dept. of Atmospheric Sciences

2013-11-13T23:59:59.000Z

450

Effects of the Training Dataset Characteristics on the Performance of Nine Species Distribution Models  

E-Print Network (OSTI)

Effects of the Training Dataset Characteristics on the Performance of Nine Species Distribution species need to be fitted to a training dataset before practical use. The training dataset of this paper is to study the effect of the training dataset characteristics on model performance and to compare

Kratochvíl, Lukas

451

Performance of numerical approximation on the calculation of two-center two-electron integrals over non-integer Slater-type orbitals using elliptical coordinates  

E-Print Network (OSTI)

The two-center two-electron Coulomb and hybrid integrals arising in relativistic and nonrelativistic ab-initio calculations of molecules are evaluated over the non-integer Slater-type orbitals via ellipsoidal coordinates. These integrals are expressed through new molecular auxiliary functions and calculated with numerical Global-adaptive method according to parameters of non-integer Slatertype orbitals. The convergence properties of new molecular auxiliary functions are investigated and the results obtained are compared with results found in the literature. The comparison for two-center twoelectron integrals is made with results obtained from one-center expansions by translation of wavefunction to same center with integer principal quantum number and results obtained from the Cuba numerical integration algorithm, respectively. The procedures discussed in this work are capable of yielding highly accurate two-center two-electron integrals for all ranges of orbital parameters.

Ali Ba?c?; Philip E. Hoggan

2014-05-21T23:59:59.000Z

452

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

E-Print Network (OSTI)

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

Peterson, Daniel Alan

2010-01-01T23:59:59.000Z

453

Numerical Analysis of the Solar Chimney Power Plant with Energy Storage Layer  

Science Journals Connector (OSTI)

Numerical simulations have been performed to analyze the characteristics of heat transfer and air flow in the solar chimney power plant system with energy storage layer. Different mathematical models for the coll...

Ming Tingzhen; Liu Wei; Pan Yuan

2009-01-01T23:59:59.000Z

454

Numerical and physical modelling of microstructure evolution – new approach to the development and optimisation of cold rolling and annealing technology of IF steel strips  

Science Journals Connector (OSTI)

Modelling of cold rolling and continuous annealing of the IF steel is the objective of the paper. Experimental plastometric tests were performed to determine flow stress in the temperature range characteristic for cold rolling. Physical simulations of the annealing were performed at various heating rates to various temperatures. The kinetics of recrystallization model based on the additivity rule was identified on the basis of the experimental results. In connection with the finite element model of cold rolling, the complex model for the whole manufacturing cycle is obtained. This model can be used for optimisation of cold rolling and annealing technology of IF steel strips.

R. KUZIAK; R. MOLENDA; M. PIETRZYK

2008-01-01T23:59:59.000Z

455

Performance Evaluation of Adaptive Ramp-Metering Algorithms Using Microscopic Traffic Simulation Model  

E-Print Network (OSTI)

to implementation on the target freeway network. In this paper, a capability-enhanced PARAMICS simulation model has evaluation; Simulation models; Algorithms. Introduction Ramp metering has been recognized as an effectivePerformance Evaluation of Adaptive Ramp-Metering Algorithms Using Microscopic Traffic Simulation

Levinson, David M.

456

Performance Modeling and Optimization of a High Energy CollidingBeam Simulation Code  

SciTech Connect

An accurate modeling of the beam-beam interaction is essential to maximizing the luminosity in existing and future colliders. BeamBeam3D was the first parallel code that can be used to study this interaction fully self-consistently on high-performance computing platforms. Various all-to-all personalized communication (AAPC) algorithms dominate its communication patterns, for which we developed a sequence of performance models using a series of micro-benchmarks. We find that for SMP based systems the most important performance constraint is node-adapter contention, while for 3D-Torus topologies good performance models are not possible without considering link contention. The best average model prediction error is very low on SMP based systems with of 3% to 7%. On torus based systems errors of 29% are higher but optimized performance can again be predicted within 8% in some cases. These excellent results across five different systems indicate that this methodology for performance modeling can be applied to a large class of algorithms.

Shan, Hongzhang; Strohmaier, Erich; Qiang, Ji; Bailey, David H.; Yelick, Kathy

2006-06-01T23:59:59.000Z

457

Use of ARM observations and numerical models to determine radiative and latent heating profiles of mesoscale convective systems for general circulation models  

SciTech Connect

This three-year project, in cooperation with Professor Bob Houze at University of Washington, has been successfully finished as planned. Both ARM (the Atmospheric Radiation Measurement Program) data and cloud-resolving model (CRM) simulations were used to identify the water budgets of clouds observed in two international field campaigns. The research results achieved shed light on several key processes of clouds in climate change (or general circulation models), which are summarized below. 1. Revealed the effect of mineral dust on mesoscale convective systems (MCSs) Two international field campaigns near a desert and a tropical coast provided unique data to drive and evaluate CRM simulations, which are TWP-ICE (the Tropical Warm Pool International Cloud Experiment) and AMMA (the African Monsoon Multidisciplinary Analysis). Studies of the two campaign data were contrasted, revealing that much mineral dust can bring about large MCSs via ice nucleation and clouds. This result was reported as a PI presentation in the 3rd ASR Science Team meeting held in Arlington, Virginia in March 2012. A paper on the studies was published in the Journal of the Atmospheric Sciences (Zeng et al. 2013). 2. Identified the effect of convective downdrafts on ice crystal concentration Using the large-scale forcing data from TWP-ICE, ARM-SGP (the Southern Great Plains) and other field campaigns, Goddard CRM simulations were carried out in comparison with radar and satellite observations. The comparison between model and observations revealed that convective downdrafts could increase ice crystal concentration by up to three or four orders, which is a key to quantitatively represent the indirect effects of ice nuclei, a kind of aerosol, on clouds and radiation in the Tropics. This result was published in the Journal of the Atmospheric Sciences (Zeng et al. 2011) and summarized in the DOE/ASR Research Highlights Summaries (see http://www.arm.gov/science/highlights/RMjY5/view). 3. Used radar observations to evaluate model simulations In cooperation with Profs. Bob Houze at University of Washington and Steven Rutledge at Colorado State University, numerical model results were evaluated with observations from W- and C-band radars and CloudSat/TRMM satellites. These studies exhibited some shortcomings of current numerical models, such as too little of thin anvil clouds, directing the future improvement of cloud microphysics parameterization in CRMs. Two papers of Powell et al (2012) and Zeng et al. (2013), summarizing these studies, were published in the Journal of the Atmospheric Sciences. 4. Analyzed the water budgets of MCSs Using ARM data from TWP-ICE, ARM-SGP and other field campaigns, the Goddard CRM simulations were carried out to analyze the water budgets of clouds from TWP-ICE and AMMA. The simulations generated a set of datasets on clouds and radiation, which are available http://cloud.gsfc.nasa.gov/. The cloud datasets were available for modelers and other researchers aiming to improve the representation of cloud processes in multi-scale modeling frameworks, GCMs and climate models. Special datasets, such as 3D cloud distributions every six minutes for TWP-ICE, were requested and generated for ARM/ASR investigators. Data server records show that 86,206 datasets were downloaded by 120 users between April of 2010 and January of 2012. 5. MMF simulations The Goddard MMF (multi-scale modeling framework) has been improved by coupling with the Goddard Land Information System (LIS) and the Goddard Earth Observing System Model, Version 5 (GOES5). It has also been optimized on NASA HEC supercomputers and can be run over 4000 CPUs. The improved MMF with high horizontal resolution (1 x 1 degree) is currently being applied to cases covering 2005 and 2006. The results show that the spatial distribution pattern of precipitation rate is well simulated by the MMF through comparisons with satellite retrievals from the CMOPRH and GPCP data sets. In addition, the MMF results were compared with three reanalyses (MERRA, ERA-Interim and CFSR). Although the MMF tends

Tao, Wei-Kuo; Houze, Robert, A., Jr.; Zeng, Xiping

2013-03-14T23:59:59.000Z

458

Statistical and Realistic Numerical Model Investigations of Anthropogenic and Climatic Factors that Influence Hypoxic Area Variability in the Gulf of Mexico  

E-Print Network (OSTI)

, Steven DiMarco George Jackson Committee Members, Robert Hetland Thomas Bianchi Piers Chapman Steven Davis Head of Department, Piers Chapman May 2012 Major Subject: Oceanography iii ABSTRACT Statistical and Realistic Numerical Model... Investigations of Anthropogenic and Climatic Factors that Influence Hypoxic Area Variability in the Gulf of Mexico. (May 2012) Yang Feng, B. S., Ocean University of China; M.S., Ocean University of China Co?Chairs of Advisory Committee: Dr. Steven Di...

Feng, Yang

2012-07-16T23:59:59.000Z

459

A Distributed Electrochemistry Modeling Tool for Simulating SOFC Performance and Degradation  

SciTech Connect

This report presents a distributed electrochemistry (DEC) model capable of investigating the electrochemistry and local conditions with the SOFC MEA based on the local microstructure and multi-physics. The DEC model can calculate the global current-voltage (I-V) performance of the cell as determined by the spatially varying local conditions through the thickness of the electrodes and electrolyte. The simulation tool is able to investigate the electrochemical performance based on characteristics of the electrode microstructure, such as particle size, pore size, electrolyte and electrode phase volume fractions, and triple-phase-boundary length. It can also investigate performance as affected by fuel and oxidant gas flow distributions and other environmental/experimental conditions such as temperature and fuel gas composition. The long-term objective for the DEC modeling tool is to investigate factors that cause electrode degradation and the decay of SOFC performance which decrease longevity.

Recknagle, Kurtis P.; Ryan, Emily M.; Khaleel, Mohammad A.

2011-10-13T23:59:59.000Z

460

Systems, methods and computer-readable media to model kinetic performance of rechargeable electrochemical devices  

DOE Patents (OSTI)

A system includes an electrochemical cell, monitoring hardware, and a computing system. The monitoring hardware samples performance characteristics of the electrochemical cell. The computing system determines cell information from the performance characteristics. The computing system also analyzes the cell information of the electrochemical cell with a Butler-Volmer (BV) expression modified to determine exchange current density of the electrochemical cell by including kinetic performance information related to pulse-time dependence, electrode surface availability, or a combination thereof. A set of sigmoid-based expressions may be included with the modified-BV expression to determine kinetic performance as a function of pulse time. The determined exchange current density may be used with the modified-BV expression, with or without the sigmoid expressions, to analyze other characteristics of the electrochemical cell. Model parameters can be defined in terms of cell aging, making the overall kinetics model amenable to predictive estimates of cell kinetic performance along the aging timeline.

Gering, Kevin L.

2013-01-01T23:59:59.000Z

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


461

User's Manual for Data for Validating Models for PV Module Performance  

SciTech Connect

This user's manual describes performance data measured for flat-plate photovoltaic (PV) modules installed in Cocoa, Florida, Eugene, Oregon, and Golden, Colorado. The data include PV module current-voltage curves and associated meteorological data for approximately one-year periods. These publicly available data are intended to facilitate the validation of existing models for predicting the performance of PV modules, and for the development of new and improved models. For comparing different modeling approaches, using these public data will provide transparency and more meaningful comparisons of the relative benefits.

Marion, W.; Anderberg, A.; Deline, C.; Glick, S.; Muller, M.; Perrin, G.; Rodriguez, J.; Rummel, S.; Terwilliger, K.; Silverman, T. J.

2014-04-01T23:59:59.000Z

462

Training Quench Performance and Quench Location of the Short Superconducting Dipole Models for the LHC  

E-Print Network (OSTI)

The short model program, started in October 1995 to study and validate design variants and assembly of the main LHC dipoles, has achieved its last phase. The last models were focused on the validation of specific design choices to be implemented in the series production, and to the study of the training performance of the coil heads. This paper reports on the manufacturing features of the recent twin-aperture short models, reviews the results of the cold tests and presents a summary of the training quench performance and quench location.

Sanfilippo, S; Tommasini, D; Venturini-Delsolaro, W

2002-01-01T23:59:59.000Z

463

Grid Reliability Performance Metrics Using Phasor Data and Model-less Algorithms,  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Reliability Performance Metrics Using Reliability Performance Metrics Using Phasor Data and Model-less Algorithms, Prototype Development and Field Test Carlos Martinez - Advanced Systems Researchers (ASR) cmartinez@asresearchers.com June 27-28 2013 Washington, DC DOE/OE Transmission Reliability Program 2 Project Objective LOAD-GENERATION CONTROL RELIABILITY PERFORMANCE REALTIME MONITORING GRID RELIABILITY PERFORMANCE PHASOR BASED AND MODELESS REALTIME MONITORING RESEARCH, PROTOTYPE AND FIELD TEST ALL APPLICATIONS IN PRODUCTION PROJECT OBJECTIVES 3 Project Analytics Approach 4 Accomplishments to be Completed in FY 2013 * Deliver to MISO the Extended Prototype Functional Specification * Complete Research, Test and Validation of Grid Post- Disturbance Reliability Metrics

464

Modeling and performance of a single-electron-beam two-FEL system  

Science Journals Connector (OSTI)

The use of a single electron beam to power a master oscillator and power amplifier was demonstrated in the Rocketdyne/Stanford experiment. This article concentrates on the performance of the downstream element under the assumption of higher performance upstream elements such as might be possible for the high-brightness systems being developed in the Los Alamos and Rocketdyne/Duke programs. The modeling covers the performance of the initial high-extraction efficiency system, the filtering, transport, and refocusing of electrons into a second wiggler, and the performance of the second system. The Rocketdyne 3D simulation code FELOPT was used in the FEL calculations.

Ralph A. Cover

1991-01-01T23:59:59.000Z

465

Observational Learning of a Bimanual Coordination Task: Understanding Movement Feature Extraction, Model Performance Level, and Perspective Angle  

E-Print Network (OSTI)

offset between the two hands. Video recordings of two models practicing over three days were used to make three videos for the study; an expert performance, discovery performance, and instruction performance video. The discovery video portrayed a decrease...

Dean, Noah J.

2010-07-14T23:59:59.000Z

466

Methodology for Constructing Reduced-Order Power Block Performance Models for CSP Applications: Preprint  

SciTech Connect

The inherent variability of the solar resource presents a unique challenge for CSP systems. Incident solar irradiation can fluctuate widely over a short time scale, but plant performance must be assessed for long time periods. As a result, annual simulations with hourly (or sub-hourly) timesteps are the norm in CSP analysis. A highly detailed power cycle model provides accuracy but tends to suffer from prohibitively long run-times; alternatively, simplified empirical models can run quickly but don?t always provide enough information, accuracy, or flexibility for the modeler. The ideal model for feasibility-level analysis incorporates both the detail and accuracy of a first-principle model with the low computational load of a regression model. The work presented in this paper proposes a methodology for organizing and extracting information from the performance output of a detailed model, then using it to develop a flexible reduced-order regression model in a systematic and structured way. A similar but less generalized approach for characterizing power cycle performance and a reduced-order modeling methodology for CFD analysis of heat transfer from electronic devices have been presented. This paper builds on these publications and the non-dimensional approach originally described.

Wagner, M.

2010-10-01T23:59:59.000Z

467

A Comparison of HCCI Engine Performance Data and Kinetic Modeling Results over a Wide Rangeof Gasoline Range Surrogate Fuel Blends  

Energy.gov (U.S. Department of Energy (DOE))

Kinetic models of fuels are needed to allow the simulation of engine performance for research, design, or verification purposes.

468

Advanced modeling and simulation to design and manufacture high performance and reliable advanced microelectronics and microsystems.  

SciTech Connect

An interdisciplinary team of scientists and engineers having broad expertise in materials processing and properties, materials characterization, and computational mechanics was assembled to develop science-based modeling/simulation technology to design and reproducibly manufacture high performance and reliable, complex microelectronics and microsystems. The team's efforts focused on defining and developing a science-based infrastructure to enable predictive compaction, sintering, stress, and thermomechanical modeling in ''real systems'', including: (1) developing techniques to and determining materials properties and constitutive behavior required for modeling; (2) developing new, improved/updated models and modeling capabilities, (3) ensuring that models are representative of the physical phenomena being simulated; and (4) assessing existing modeling capabilities to identify advances necessary to facilitate the practical application of Sandia's predictive modeling technology.

Nettleship, Ian (University of Pittsburgh, Pittsburgh, PA); Hinklin, Thomas; Holcomb, David Joseph; Tandon, Rajan; Arguello, Jose Guadalupe, Jr. (,; .); Dempsey, James Franklin; Ewsuk, Kevin Gregory; Neilsen, Michael K.; Lanagan, Michael (Pennsylvania State University, University Park, PA)

2007-07-01T23:59:59.000Z

469

Development of a Model Specification for Performance MonitoringSystems for Commercial Buildings  

SciTech Connect

The paper describes the development of a model specification for performance monitoring systems for commercial buildings. The specification focuses on four key aspects of performance monitoring: (1) performance metrics; (2) measurement system requirements; (3) data acquisition and archiving; and (4) data visualization and reporting. The aim is to assist building owners in specifying the extensions to their control systems that are required to provide building operators with the information needed to operate their buildings more efficiently and to provide automated diagnostic tools with the information required to detect and diagnose faults and problems that degrade energy performance. The paper reviews the potential benefits of performance monitoring, describes the specification guide and discusses briefly the ways in which it could be implemented. A prototype advanced visualization tool is also described, along with its application to performance monitoring. The paper concludes with a description of the ways in which the specification and the visualization tool are being disseminated and deployed.

Haves, Philip; Hitchcock, Robert J.; Gillespie, Kenneth L.; Brook, Martha; Shockman, Christine; Deringer, Joseph J.; Kinney,Kristopher L.

2006-08-01T23:59:59.000Z

470

Study of the comprehensive risk analysis of dam-break flooding based on the numerical simulation of flood routing. Part II: Model application and results  

Science Journals Connector (OSTI)

The present model and methodology described in Part I of this work are applied to perform a comprehensive risk analysis of the dam-break flood of five reservoirs in the Haihe River ... The results indicate that t...

Zhengyin Zhou; Xiaoling Wang; Ruirui Sun; Xuefei Ao; Xiaopei Sun…

2014-06-01T23:59:59.000Z

471

Numerical investigation of the physical model of a high-power electromagnetic wave in a magnetically insulated transmission line  

SciTech Connect

An efficient numerical code for simulating the propagation of a high-power electromagnetic pulse in a vacuum transmission line is required to study the physical phenomena occurring in such a line, to analyze the operation of present-day megavolt generators at an {approx}10-TW power level, and to design such new devices. The main physical theoretical principles are presented, and the stability of flows in the near-threshold region at the boundary of the regime of magnetic self-insulation is investigated based on one-dimensional telegraph equations with electron losses. Numerical (difference) methods-specifically, a method of characteristics and a finite-difference scheme-are described and their properties and effectiveness are compared by analyzing the high-frequency modes.

Samokhin, A. A. [Troitsk Institute for Innovation and Fusion Research (Russian Federation)

2010-02-15T23:59:59.000Z

472

Peer review presentation on systems performance modeling and solar advisor support.  

SciTech Connect

Accurate Performance Models are Critical to Project Development and Technology Evaluation - Accuracy and Uncertainty of Commonly-Used Models Unknown and Models Disagree. A Model Evaluation Process Has Been Developed with Industry, and High-Quality Weather and System Performance Data Sets Have Been Collected: (1) Evaluation is Underway using Residual Analysis of Hourly and Sub-Hourly Data for Clear and Diffuse Climates to Evaluate and Improve Models; and (2) Initial Results Have Been or Will Soon Be Presented at Key Conferences. Evaluation of Widely-Used Module, Inverter, and Irradiance Models, Including Those in SAM, PVWatts, and PVSyst, Will Be Completed This Year. Stochastic Modeling Has Been Performed to Support Reliability Task and Will Add Value to Parametric Analysis. An Industry Workshop will be Held This Fall To Review Results, Set Priorities. Support and Analysis has been Provided for TPP's, SETP, and PV Community. Goals for Future Work Include: (1) Improving Understanding of and Validating System Derate Factors; and (2) Developing a Dynamic Electrical Model of Arrays with Shaded or Mismatched Modules to Support Transient Analysis of Large Fields.

Cameron, Christopher P.

2010-05-01T23:59:59.000Z

473

Nuclear Energy Advanced Modeling and Simulation Waste Integrated Performance and Safety Codes (NEAMS Waste IPSC).  

SciTech Connect

The objective of the U.S. Department of Energy Office of Nuclear Energy Advanced Modeling and Simulation Waste Integrated Performance and Safety Codes (NEAMS Waste IPSC) is to provide an integrated suite of computational modeling and simulation (M&S) capabilities to quantitatively assess the long-term performance of waste forms in the engineered and geologic environments of a radioactive-waste storage facility or disposal repository. Achieving the objective of modeling the performance of a disposal scenario requires describing processes involved in waste form degradation and radionuclide release at the subcontinuum scale, beginning with mechanistic descriptions of chemical reactions and chemical kinetics at the atomic scale, and upscaling into effective, validated constitutive models for input to high-fidelity continuum scale codes for coupled multiphysics simulations of release and transport. Verification and validation (V&V) is required throughout the system to establish evidence-based metrics for the level of confidence in M&S codes and capabilities, including at the subcontiunuum scale and the constitutive models they inform or generate. This Report outlines the nature of the V&V challenge at the subcontinuum scale, an approach to incorporate V&V concepts into subcontinuum scale modeling and simulation (M&S), and a plan to incrementally incorporate effective V&V into subcontinuum scale M&S destined for use in the NEAMS Waste IPSC work flow to meet requirements of quantitative confidence in the constitutive models informed by subcontinuum scale phenomena.

Schultz, Peter Andrew

2011-12-01T23:59:59.000Z

474

Empirical Performance Model-Driven Data Layout Optimization and Library Call Selection for Tensor Contraction Expressions  

SciTech Connect

Empirical optimizers like ATLAS have been very effective in optimizing computational kernels in libraries. The best choice of parameters such as tile size and degree of loop unrolling is determined by executing different versions of the computation. In contrast, optimizing compilers use a model-driven approach to program transformation. While the model-driven approach of optimizing compilers is generally orders of magnitude faster than ATLAS-like library generators, its effectiveness can be limited by the accuracy of the performance models used. In this paper, we describe an approach where a class of computations is modeled in terms of constituent operations that are empirically measured, thereby allowing modeling of the overall execution time. The performance model with empirically determined cost components is used to perform data layout optimization together with the selection of library calls and layout transformations in the context of the Tensor Contraction Engine, a compiler for a high-level domain-specific language for expressing computational models in quantum chemistry. The effectiveness of the approach is demonstrated through experimental measurements on representative computations from quantum chemistry.

Lu, Qingda; Gao, Xiaoyang; Krishnamoorthy, Sriram; Baumgartner, Gerald; Ramanujam, J.; Sadayappan, Ponnuswamy

2012-03-01T23:59:59.000Z

475

Fuel performance models for high-temperature gas-cooled reactor core design  

SciTech Connect

Mechanistic fuel performance models are used in high-temperature gas-cooled reactor core design and licensing to predict failure and fission product release. Fuel particles manufactured with defective or missing SiC, IPyC, or fuel dispersion in the buffer fail at a level of less than 5 x 10/sup -4/ fraction. These failed particles primarily release metallic fission products because the OPyC remains intact on 90% of the particles and retains gaseous isotopes. The predicted failure of particles using performance models appears to be conservative relative to operating reactor experience.

Stansfield, O.M.; Simon, W.A.; Baxter, A.M.

1983-09-01T23:59:59.000Z

476

Development of long-term performance models for radioactive waste forms  

SciTech Connect

The long-term performance of solid radioactive waste is measured by the release rate of radionuclides into the environment, which depends on corrosion or weathering rates of the solid waste form. The reactions involved depend on the characteristics of the solid matrix containing the radioactive waste, the radionuclides of interest, and their interaction with surrounding geologic materials. This chapter describes thermo-hydro-mechanical and reactive transport models related to the long-term performance of solid radioactive waste forms, including metal, ceramic, glass, steam reformer and cement. Future trends involving Monte-Carlo simulations and coupled/multi-scale process modeling are also discussed.

Bacon, Diana H.; Pierce, Eric M.

2011-03-22T23:59:59.000Z

477

Validation of PV performance models using satellite-based irradiance measurements : a case study.  

SciTech Connect

Photovoltaic (PV) system performance models are relied upon to provide accurate predictions of energy production for proposed and existing PV systems under a wide variety of environmental conditions. Ground based meteorological measurements are only available from a relatively small number of locations. In contrast, satellite-based radiation and weather data (e.g., SUNY database) are becoming increasingly available for most locations in North America, Europe, and Asia on a 10 x 10 km grid or better. This paper presents a study of how PV performance model results are affected when satellite-based weather data is used in place of ground-based measurements.

Stein, Joshua S.; Parkins, Andrew (Clean Power Research); Perez, Richard (University at Albany)

2010-05-01T23:59:59.000Z

478

Florian SEITZ: Atmospheric and oceanic impacts to Earth rotations numerical studies with a dynamic Earth system model  

E-Print Network (OSTI)

with a dynamic Earth system model (completed in October 2004) Variations of Earth rotation are caused Earth system model DyMEG has been developed. It is based on the balance of angular momentum

Schuh, Harald

479

Numerical studies of a one-dimensional three-spin spin-glass model with long-range interactions  

E-Print Network (OSTI)

We study a p-spin spin-glass model to understand if the finite-temperature glass transition found in the mean-field regime of p-spin models, and used to model the behavior of structural glasses, persists in the nonmean-field regime. By using a three...

Larson, Derek; Katzgraber, Helmut G.; Moore, M. A.; Young, A. P.

2010-01-01T23:59:59.000Z

480

Energy Modeling of a High Performance Building in the U.A.E. for Sustainability Certification  

E-Print Network (OSTI)

voluntary LEED program. BUILDING CONCEPT AND MODELING Modeling The simulation tool used to analyze the energy per- formance of the Sheikh Zayed Desert Learning Centre is TRNSYS version 16.01 (Solar Energy Laboratory, Univ. of Wisconsin-Madison 2004...). TRNSYS is a dynamic simulation platform for simulating systems over time pe- riods from days to years at time-steps of seconds to hours. TRNSYS meets the requirements for LEED certification of energy performance through the whole building simu...

Jones, M.; Ledinger, S.

2010-01-01T23:59:59.000Z

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


481

Soil moisture in complex terrain: quantifying effects on atmospheric boundary layer flow and providing improved surface boundary conditions for mesoscale models  

E-Print Network (OSTI)

compressible numerical weather prediction model incompressible numerical weather prediction model withcompressible numerical weather prediction model in

Daniels, Megan Hanako

2010-01-01T23:59:59.000Z

482

1 MODELING THE PERFORMANCE OF ULTRAVIOLET REACTOR IN EULERIAN AND LAGRANGIAN FRAMEWORKS  

E-Print Network (OSTI)

CFD models for simulating the performance of ultraviolet (UV) reactors for micro-organism inactivation were developed in Eulerian and Lagrangian frameworks, taking into account hydrodynamics, kinetics, and radiation field within UV reactor. In the Lagrangian framework, micro-organisms were treated as discrete particles where the trajectory was predicted by integrating the force balance on the particle. In the Eulerian framework, the conservation equation of species (microorganisms) was solved along with the transport equations. The fluid flow was characterized experimentally using particle image velocimetry (PIV) flow visualization techniques and modeled using CFD for a UV reactor prototype model. The performance of annular UV reactors with an inlet parallel and perpendicular to the reactor axis were investigated. The results indicated that the fluid flow distribution within the reactor volume can significantly affect the reactor performance. Both the Eulerian and Lagrangian models were used to obtain complimentary information on the reactors; while the Lagrangian method provided an estimation of the UV-fluence distribution and the trajectory of species, the Eulerian approach showed the concentration distribution and local photo-reaction rates. The combined information can be used to predict and monitor reactor performance and to improve the reactor design.

Angelo Sozzi; Fariborz Taghipour

2006-01-01T23:59:59.000Z

483

Performance Optimization by Wire and Buffer Sizing Under the Transmission Line Model \\Lambda  

E-Print Network (OSTI)

Performance Optimization by Wire and Buffer Sizing Under the Transmission Line Model \\Lambda Tai to the time­of­flight delay of a line, it is necessary to consider the transmission line behavior for de­ lay on this formula, we show the property that the minimum delay for a transmission line with reflection occurs when

Chen, Tai-Chen

484

High-Performance Torque Control for Switched Reluctance Motor Based on Online Fuzzy Neural Network Modeling  

Science Journals Connector (OSTI)

A novel high performance torque control scheme for switched reluctance motors(SRMs) is proposed based on online fuzzy neural network modeling and adaptive sliding-mode current control. Firstly, an adaptive neural fuzzy inference system(ANFIS) is designed ... Keywords: switched reluctance motor, torque control, adaptive neural fuzzy inference system, adaptive sliding mode control

Xuelian Yao; Ruiyun Qi; Zhiquan Deng; Jun Cai

2010-10-01T23:59:59.000Z

485

Modeling Process Characteristics and Performance of Fixed and Fluidized Bed Regenerative Thermal Oxidizer  

Science Journals Connector (OSTI)

Modeling Process Characteristics and Performance of Fixed and Fluidized Bed Regenerative Thermal Oxidizer ... (7)?Cheng, W.-H.; Chou, M.-S.; Lee, W.-S.; Huang, B.-J. Applications of Low-Temperature Regenerative Thermal Oxidizers to Treat Volatile Organic Compounds. ...

Pietropaolo Morrone; Francesco P. Di Maio; Alberto Di Renzo; Mario Amelio

2006-05-26T23:59:59.000Z

486

Analysis of Molten Carbonate Fuel Cell Performance Using a Three-Phase Homogeneous Model  

E-Print Network (OSTI)

temperatures, nickel oxide dissolves in the melt. This slow loss of active material contributes to an increase as compared to nickel oxide. The search for alternate cathode materials could be simplified through the use-phase homogeneous model was developed to simulate the performance of the molten carbonate fuel cell MCFC cathode

Popov, Branko N.

487

Performance modeling and cell design for high concentration methanol fuel cells  

E-Print Network (OSTI)

) it reduces the fuel efficiency (methanol is reacted without producing electrical current). We canChapter 50 Performance modeling and cell design for high concentration methanol fuel cells C. E The direct methanol fuel cell (DMFC) has become a lead- ing contender to replace the lithium-ion (Li

488

Modeling the Performance, Emissions, and Cost of an Entrained-Flow Gasification Combined Cycle System Using  

E-Print Network (OSTI)

1 Modeling the Performance, Emissions, and Cost of an Entrained-Flow Gasification Combined Cycle-based Integrated Gasification Combined Cycle (IGCC) system using ASPEN. ASPEN is a steady-state chemical process-flow Integrated Gasification Combined Cycle (IGCC) system. This study aims at developing a base case analysis

Frey, H. Christopher

489

Propagating Uncertainty in Solar Panel Performance for Life Cycle Modeling in Early Stage Design  

E-Print Network (OSTI)

Propagating Uncertainty in Solar Panel Performance for Life Cycle Modeling in Early Stage Design. This work is conducted in the context of an amorphous photovoltaic (PV) panel, using data gathered from the National Solar Radiation Database, as well as realistic data collected from an experimental hardware setup

Yang, Maria

490

Industrial environmental performance evaluation: A Markov-based model considering data uncertainty  

Science Journals Connector (OSTI)

Commonly, operational aspects of an industrial process are not included when evaluating the process environmental performance. These aspects are important as operational failures can intensify adverse environmental impacts or can diminish the chance ... Keywords: Decision-making, Environmental model, Industrial process, Maintenance, Markov chain, Uncertainty

Samaneh Shokravi, Alan J. R. Smith, Colin R. Burvill

2014-10-01T23:59:59.000Z

491

A unified model for the detailed investigation of membrane modules and RO plants performance  

Science Journals Connector (OSTI)

In this work a straightforward procedure for the detailed investigation of the performance of the membrane modules and RO plants has been suggested. The analysis is based on analytical equations for a two dimensional flow of two components and determines the permeate flow rate and the quality of the produced water. A software was developed, based in the proposed mathematical model, which can predict the brine and permeate characteristics for every individual membrane module in the pressure vessels in an RO plant, regardless of the type of the membranes. The predictions of the proposed software were verified by experimental data for a 380 m3/d RO plant, with 8'' membrane module made by FilmTec. An excellent agreement was found between the prediction of the suggested model and the experimental data. The membrane performance predictions of the developed software were also compared and verified with the predictions made by commercial softwares of different membrane producers. The model can make prediction for any parameter at any point of the process. An equation for the permeate pressure in the membrane envelop was developed and the permeate pressure profile was presented and suggestions were made for possible weak points of the membrane envelops. It is believed that the analytical model which is presented in this work is a simple, accurate and quick procedure for modeling the RO plants performance and it can be applied in any type of membrane modul

S.A. Avlonitis; M. Pappas; K. Moutesidis

2007-01-01T23:59:59.000Z

492

Modeling and controller performance assessment for a switched reluctance motor drive based on setpoint relay  

Science Journals Connector (OSTI)

This paper considers the implementation of a current control method for switched reluctance motors (SRMs) and presents a novel approach to the accurate on-line modeling of an SRM drive. A simple autotuning technique for the SRM drives using a PWM controller is considered. Furthermore, conventi