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Note: This page contains sample records for the topic "numerical modeling performance" from the National Library of EnergyBeta (NLEBeta).
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1

Pacific Hindcast Performance of Three Numerical Wave Models  

Science Conference Proceedings (OSTI)

Although mean or integral properties of wave spectra are typically used to evaluate numerical wave model performance, one must look into the spectral details to identify sources of model deficiencies. This creates a significant problem, as basin-...

Jeffrey L. Hanson; Barbara A. Tracy; Hendrik L. Tolman; R. Douglas Scott

2009-08-01T23:59:59.000Z

2

Using Temporal Modes of Rainfall to Evaluate the Performance of a Numerical Weather Prediction Model  

Science Conference Proceedings (OSTI)

The authors demonstrate that much can be learned about the performance of a numerical weather prediction (NWP) model by examining the temporal modes of its simulated rainfall. Observations from the Weather Surveillance Radar-1988 Doppler (WSR-88D)...

Jason C. Knievel; David A. Ahijevych; Kevin W. Manning

2004-12-01T23:59:59.000Z

3

Numerical Modeling  

Science Conference Proceedings (OSTI)

Feb 28, 2011... or field repair, durability, weight and cost efficiency, and extreme climate. ... Cohesive zone model is implemented to investigate the interfacial ...

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  

DOE Green Energy (OSTI)

This report describes a technique of using a mass-consistent model to derive wind speeds over a microscale region of complex terrain. A serious limitation in the use of these numerical models is that the calculated wind field is highly sensitive to some input parameters, such as those specifying atmospheric stability. Because accurate values for these parameters are not usually known, confidence in the calculated winds is low. However, values for these parameters can be found by tuning the model to existing wind observations within a microscale area. This tuning is accomplished by using a single-variable, unconstrained optimization procedure that adjusts the unknown parameters so that the error between the observed winds and model calculations of these winds is minimized. Model verification is accomplished by using eight sets of hourly averaged wind data. These data are obtained from measurements made at approximately 30 sites covering a wind farm development in the Altamont Pass area. When the model is tuned to a small subset of the 30 sites, an accurate determination of the wind speeds was made for the remaining sites in six of the eight cases. (The two that failed were low wind speed cases.) Therefore, when this technique is used, numerical modeling shows great promise as a tool for microscale siting of wind turbines in complex terrain.

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

1985-09-01T23:59:59.000Z

6

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 the energy saving potential and economical benefits of microturbine and its combined production system, a simple mathematical model of microturbine is proposed. Part-load characteristics of main components are also considered for analyzing the unit's performance under off-design situations. The proposed model is validated by operational data of a commercially available micro- turbine from a reference. The result shows that the proposed mathematical model can preferably represent the quasi-static operational features of microturbine.

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

2006-01-01T23:59:59.000Z

7

A preliminary evaluation of the performance of wind tunnel and numerical modeling simulations of the wind flow over a wind farm  

SciTech Connect

This report is an analysis of physical and numerical model simulations of the wind flow over complex terrain. The specific area to which these models were applied is a wind farm in the Altamont Pass area of California. The physical model results were obtained from wind tunnel flow simulations, and the numerical model used was the optimizing version of the NOABL model. The goals of this analysis were (1) to evaluate the relative performance of the two models and (2) to uncover any clues that would point toward improvement of the wind tunnel modeling. The performances of the models were gauged by comparing model simulations to wind observations taken over the modeled area.

Barnard, J.C.; Wegley, H.L.

1987-01-01T23:59:59.000Z

8

Numerical modeling of the temperature illumination intensity dependent performance of CIS solar cells  

DOE Green Energy (OSTI)

In this paper, the temperature dependence of CIS solar cell illuminated I-V is studied numerically using ADEPT. The effects of having a second junction either at the interface or at the back contact are investigated. These two placements of the second junction result in two distinctive shapes of the I-V at low temperatures. Both of these distinctive shapes have been observed experimentally.

Lee, Y.J.; Gray, J.L. [Purdue Univ., Lafayette, IN (United States). School of Electrical Engineering

1994-12-31T23:59:59.000Z

9

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

10

Modeling the performance of a two-phase turbine using numerical methods and the results of nozzle, static cascade, and windage experiments  

DOE Green Energy (OSTI)

Performance models for a two-phase turbine were developed to verify the understanding of the loss mechanisms and to extrapolate from the single-nozzle test condition to a full-admission turbine. The numerical models for predicting the performance of the nozzle and the combined nozzle and rotor are described. Results from two-phase, static cascade tests and disk-friction and windage experiments are used to calibrate the performance model(s). Model predictions are compared with single-nozzle prototype-turbine test results, and extrapolations are made to a full-admission design. The modeling also provides predictions of performance for turbines with various blade geometries, inlet conditions, and droplet sizes. Thus the modeling provides insight into design improvements.

Comfort, W.J. III

1978-06-21T23:59:59.000Z

11

Waste glass melter numerical and physical modeling  

SciTech Connect

Results of physical and numerical simulation modeling of high-level liquid waste vitrification melters are presented. Physical modeling uses simulant fluids in laboratory testing. Visualization results provide insight into convective melt flow patterns from which information is derived to support performance estimation of operating melters and data to support numerical simulation. Numerical simulation results of several melter configurations are presented. These are in support of programs to evaluate melter operation characteristics and performance. Included are investigations into power skewing and alternating current electric field phase angle in a dual electrode pair reference design and bi-modal convective stability in an advanced design. 9 refs., 9 figs., 1 tab.

Eyler, L.L.; Peters, R.D.; Lessor, D.L.; Lowery, P.S.; Elliott, M.L.

1991-10-01T23:59:59.000Z

12

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

13

Numerical Modeling and Optimization of Microstructure Evolution ...  

Science Conference Proceedings (OSTI)

Presentation Title, Numerical Modeling and Optimization of Microstructure Evolution ... A Hybrid Model on Low Energy Ion Beam Processing Leading to Phase ...

14

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

Science Conference Proceedings (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

15

Hurricane Track Prediction Using a Statistical Ensemble of Numerical Models  

Science Conference Proceedings (OSTI)

A new statistical ensemble prediction system for tropical cyclone tracks is presented. The system is based on a statistical analysis of the annual performance of numerical track prediction models, assuming that their position errors are ...

Harry C. Weber

2003-05-01T23:59:59.000Z

16

A Numerical Model of the Ventilated Thermocline  

Science Conference Proceedings (OSTI)

A steady state numerical solution is found for an idealized, rectangular ocean basin driven by wind and surface buoyancy flux. A three-dimensional primitive equation model is used. In agreement with recent analytical modeling, the thermocline in ...

Michael D. Cox; Kirk Bryan

1984-04-01T23:59:59.000Z

17

Numerical wind speed simulation model  

DOE Green Energy (OSTI)

A relatively simple stochastic model for simulating wind speed time series that can be used as an alternative to time series from representative locations is described in this report. The model incorporates systematic seasonal variation of the mean wind, its standard deviation, and the correlation speeds. It also incorporates systematic diurnal variation of the mean speed and standard deviation. To demonstrate the model capabilities, simulations were made using model parameters derived from data collected at the Hanford Meteorology Station, and results of analysis of simulated and actual data were compared.

Ramsdell, J.V.; Athey, G.F.; Ballinger, M.Y.

1981-09-01T23:59:59.000Z

18

Heat Sink Performance Analysis through Numerical Technique  

E-Print Network (OSTI)

The increase in dissipated power per unit area of electronic components sets higher demands on the performance of the heat sink. Also if we continue at our current rate of miniaturisation, laptops and other electronic devices can get heated up tremendously. Hence we require a better heat dissipating system to overcome the excess heat generating problem of using nanoelectronics, which is expected to power the next generation of computers. To handle the excessive and often unpredictable heating up of high performance electronic components like microprocessors, we need to predict the temperature profile of the heat sink used. This also helps us to select the best heat sink for the operating power range of any microprocessor. Understanding the temperature profile of a heat sink and a microprocessor helps us to handle its temperature efficiently for a range of loads. In this work, a method to estimate the normal response of a heat sink to various loads of a microprocessor is explained.

Aravindh, B Sri; Nair, T R Gopalakrishnan

2010-01-01T23:59:59.000Z

19

On a numerical model for gasification of biomass materials  

Science Conference Proceedings (OSTI)

In this paper, a thermochemical equilibrium model is used to predict the performance of a downdraft gasifier. Numerical results are shown to be in good agreement with those of the experiments. Different biomass materials are tested using the model and ... Keywords: biomass, gasification, mathematical modeling, renewable energy, thermochemical equilibrium

Mahdi Vaezi; Mohammad Passandideh-Fard; Mohammad Moghiman

2007-12-01T23:59:59.000Z

20

High-performance numerical optimization on multicore clusters  

Science Conference Proceedings (OSTI)

This paper presents a software infrastructure for high performance numerical optimization on clusters of multicore systems. At the core, a runtime system implements a programming and execution environment for irregular and adaptive task-based parallelism. ... Keywords: global optimization, message passing, numerical differentiation, task parallelism

Panagiotis E. Hadjidoukas; Constantinos Voglis; Vassilios V. Dimakopoulos; Isaac E. Lagaris; Dimitris G. Papageorgiou

2011-08-01T23:59:59.000Z

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

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.

22

Numerical modeling of liquid geothermal systems  

DOE Green Energy (OSTI)

A mathematical model describing the physical behavior of hot-water geothermal systems is presented. The model consists of a set of coupled partial differential equations for heat and mass transfer in porous media and an equation of state relating fluid density to temperature and pressure. The equations are solved numerically using an integrated finite difference method which can treat arbitrary nodal configurations in one, two, or three dimensions. The model is used to analyze cellular convection in permeable rock layers heated from below. Results for cases with constant fluid and rock properties are in good agreement with numerical and experimental results from other authors.

Sorey, M.L.

1978-01-01T23:59:59.000Z

23

Microcomputer Numerical Ocean Surface Wave Model  

Science Conference Proceedings (OSTI)

A numerical wean surface wave model has been developed specifically to operate on desktop super micro-computers. The model uses one or more local and moving grids within which waves of importance at a location of interest are generated. Within ...

Marshall D. Earle

1989-02-01T23:59:59.000Z

24

Efficient numerical modeling of borehole heat exchangers  

Science Conference Proceedings (OSTI)

This paper presents a finite element modeling technique for double U-tube borehole heat exchangers (BHE) and the surrounding soil mass. Focus is placed on presenting numerical analyses describing the capability of a BHE model, previously reported, to ... Keywords: BHE, Geothermal heat pumps, Geothermic, Heat transfer, Space heating

R. Al-Khoury; T. Kölbel; R. Schramedei

2010-10-01T23:59:59.000Z

25

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.

26

Numerical Modeling of Centrifugally Cast HSS Rolls  

Science Conference Proceedings (OSTI)

This model will help to further understand the complex solidification behavior of the HSS roll. Performance of the HSS roll requires proper formation and ...

27

Photovoltaic array performance model.  

DOE Green Energy (OSTI)

This document summarizes the equations and applications associated with the photovoltaic array performance model developed at Sandia National Laboratories over the last twelve years. Electrical, thermal, and optical characteristics for photovoltaic modules are included in the model, and the model is designed to use hourly solar resource and meteorological data. The versatility and accuracy of the model has been validated for flat-plate modules (all technologies) and for concentrator modules, as well as for large arrays of modules. Applications include system design and sizing, 'translation' of field performance measurements to standard reporting conditions, system performance optimization, and real-time comparison of measured versus expected system performance.

Kratochvil, Jay A.; Boyson, William Earl; King, David L.

2004-08-01T23:59:59.000Z

28

Field-Object Design of a Numerical Weather Prediction Model for Uni- and Multiprocessors  

Science Conference Proceedings (OSTI)

The performance of a numerical weather model constructed from scalar, vector, and tensor field objects is evaluated on several workstation computers and on a message-passing multiprocessor.

D. K. Purnell; M. J. Revell; P. N. McGavin

1995-02-01T23:59:59.000Z

29

Radiation Boundary Conditions in Numerical Modeling  

Science Conference Proceedings (OSTI)

A two-dimensional anelastic model is used to study the propagation of errors arising from the use of open lateral boundaries. Reference experiments were performed using very large horizontal domains. Other experiments were carried out in smaller ...

Mark Hedley; M. K. Yau

1988-09-01T23:59:59.000Z

30

Physical and numerical modeling of Joule-heated melters  

SciTech Connect

The Joule-heated ceramic-lined melter is an integral part of the high level waste immobilization process under development by the US Department of Energy. Scaleup and design of this waste glass melting furnace requires an understanding of the relationships between melting cavity design parameters and the furnace performance characteristics such as mixing, heat transfer, and electrical requirements. Developing empirical models of these relationships through actual melter testing with numerous designs would be a very costly and time consuming task. Additionally, the Pacific Northwest Laboratory (PNL) has been developing numerical models that simulate a Joule-heated melter for analyzing melter performance. This report documents the method used and results of this modeling effort. Numerical modeling results are compared with the more conventional, physical modeling results to validate the approach. Also included are the results of numerically simulating an operating research melter at PNL. Physical Joule-heated melters modeling results used for qualiying the simulation capabilities of the melter code included: (1) a melter with a single pair of electrodes and (2) a melter with a dual pair (two pairs) of electrodes. The physical model of the melter having two electrode pairs utilized a configuration with primary and secondary electrodes. The principal melter parameters (the ratio of power applied to each electrode pair, modeling fluid depth, electrode spacing) were varied in nine tests of the physical model during FY85. Code predictions were made for five of these tests. Voltage drops, temperature field data, and electric field data varied in their agreement with the physical modeling results, but in general were judged acceptable. 14 refs., 79 figs., 17 tabs.

Eyler, L.L.; Skarda, R.J.; Crowder, R.S. III; Trent, D.S.; Reid, C.R.; Lessor, D.L.

1985-10-01T23:59:59.000Z

31

NUMERICAL MODELING OF CATHODE CONTACT MATERIAL DENSIFICATION  

Science Conference Proceedings (OSTI)

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

32

Numerical Model Studies of Long-Period Edge Waves  

Science Conference Proceedings (OSTI)

A numerical modeling study of aspects of the generation and propagation of long-period edge waves along a continental shelf is described. The numerical model is based on the traditional shallow-water dynamics. A scale analysis indicates that ...

F. A. Shillington; D. Van Foreest

1986-08-01T23:59:59.000Z

33

A Numerical Model for Combustion of Bubbling Thermoplastic ...  

Science Conference Proceedings (OSTI)

... the highly viscous nature of softening coal, the model ... unity in the region close to the ... dependent numerical model of burning thermoplastic materials ...

2004-12-27T23:59:59.000Z

34

Performance modeling of Beamlet  

SciTech Connect

Detailed modeling of beam propagation in Beamlet has been made to predict system performance. New software allows extensive use of optical component characteristics. This inclusion of real optical component characteristics has resulted in close agreement between calculated and measured beam distributions.

Auerbach, J.M.; Lawson, J.K.; Rotter, M.D.; Sacks, R.A.; Van Wonterghem, B.W.; Williams, W.H.

1995-06-27T23:59:59.000Z

35

A Vertically Nested Regional Numerical Weather Prediction Model with Second-Order Closure Physics  

Science Conference Proceedings (OSTI)

The model we describe involves a unique strategy in which a high vertical resolution grid is nested within the coarse vertical resolution grid of a regional numerical weather prediction (NWP) model. Physics computations performed on the high ...

Stephen D. Burk; William T. Thompson

1989-11-01T23:59:59.000Z

36

High Performance Computing: Modeling & Simulation  

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

High Performance Computing: Modeling & Simulation High Performance Computing: Modeling & Simulation Express Licensing Adaptive Real-Time Methodology for Optimizing Energy-Efficient...

37

Numerical models for high beta magnetohydrodynamic flow  

Science Conference Proceedings (OSTI)

The fundamentals of numerical magnetohydrodynamics for highly conducting, high-beta plasmas are outlined. The discussions emphasize the physical properties of the flow, and how elementary concepts in numerical analysis can be applied to the construction of finite difference approximations that capture these features. The linear and nonlinear stability of explicit and implicit differencing in time is examined, the origin and effect of numerical diffusion in the calculation of convective transport is described, and a technique for maintaining solenoidality in the magnetic field is developed. Many of the points are illustrated by numerical examples. The techniques described are applicable to the time-dependent, high-beta flows normally encountered in magnetically confined plasmas, plasma switches, and space and astrophysical plasmas. 40 refs.

Brackbill, J.U.

1987-01-01T23:59:59.000Z

38

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"

39

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

Open Energy Info (EERE)

Hydro-Thermo-Mechanical Numerical Model For Hdr Geothermal Reservoir Evaluation Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A...

40

Numerical Experiments on Consistent Horizontal and Vertical Resolution for Atmospheric Models and Observing Systems  

Science Conference Proceedings (OSTI)

Simple numerical experiments are performed in order to determine the effects of inconsistent combinations of horizontal and vertical resolution in both atmospheric models and observing systems. In both cases, we find that inconsistent spatial ...

Michael S. Fox-Rabinovitz; Richard S. Lindzen

1993-01-01T23:59:59.000Z

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.


41

Direct Numerical Simulation of the Turbulent Ekman Layer: Evaluation of Closure Models  

Science Conference Proceedings (OSTI)

A direct numerical simulation (DNS) at a Reynolds number of 1000 was performed for the neutral atmospheric boundary layer (ABL) using the Ekman layer approximation. The DNS results were used to evaluate several closure approximations that model ...

Stuart Marlatt; Scott Waggy; Sedat Biringen

2012-03-01T23:59:59.000Z

42

Explosive East Coast Cyclogenesis: Numerical Experimentation and Model-Based Diagnostics  

Science Conference Proceedings (OSTI)

Numerical experimentation of explosive East Coast cyclogenesis is performed using the Florida State University Global Spectral Model (FSUGSM). The three cases examined here are the Presidents'Day storm of 18–19 February 1979 and the North ...

John Manobianco

1989-11-01T23:59:59.000Z

43

Numerical Modeling of Meander and Eddy Formation in the Azores Current Frontal Zone  

Science Conference Proceedings (OSTI)

Numerical experiments with an 11-level primitive equation, finite-difference model in a periodic channel are performed to analyze the properties of unstable finite-amplitude disturbances in an idealized Azores Current. Release of available ...

Jürgen Kielmann; Rolf H. Käse

1987-04-01T23:59:59.000Z

44

A Benchmark Simulation for Moist Nonhydrostatic Numerical Models  

Science Conference Proceedings (OSTI)

A benchmark solution that facilitates testing the accuracy, efficiency, and efficacy of moist nonhydrostatic numerical model formulations and assumptions is presented. The solution is created from a special configuration of moist model processes ...

George H. Bryan; J. Michael Fritsch

2002-12-01T23:59:59.000Z

45

A Numerical Model for Low-Frequency Equatorial Dynamics  

Science Conference Proceedings (OSTI)

A fast, efficient numerical procedure for modeling the linear low-frequency motions on an equatorial beta plane is developed. The model is capable of simulating the seasonal and interannual variability in realistically shaped ocean basins forced ...

Mark A. Cane; Randall J. Patton

1984-12-01T23:59:59.000Z

46

The Fleet Numerical Oceanography Center Global Spectral Ocean Wave Model  

Science Conference Proceedings (OSTI)

The Spectral Ocean Wave Model (SOWM) has been an operational product at Fleet Numerical Oceanography Center since the mid 1970s; the Global Spectral Ocean Wave Model (GSOWM) was developed to replace it. An operational test of GSOWM, using buoy, ...

R. M. Clancy; J. E. Kaitala; L. F. Zambresky

1986-05-01T23:59:59.000Z

47

Numerical Simulation and Modelling of Electronic and Biochemical Systems  

Science Conference Proceedings (OSTI)

Numerical simulation and modelling are witnessing a resurgence. Designing systems with integrated wireless components, mixed-signal blocks and nanoscale, multi-GHz "digital" circuits is requiring extensive low-level modelling and simulation. Analysis ...

Jaijeet Roychowdhury

2009-02-01T23:59:59.000Z

48

Linear Spectral Numerical Model for Internal Gravity Wave Propagation  

Science Conference Proceedings (OSTI)

A three-dimensional linear spectral numerical model is proposed to simulate the propagation of internal gravity wave fluctuations in a stably stratified atmosphere. The model is developed to get first-order estimations of gravity wave ...

J. Marty; F. Dalaudier

2010-05-01T23:59:59.000Z

49

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

50

Numerical modeling of dish-Stirling reflux solar receivers  

DOE Green Energy (OSTI)

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

51

Numerical investigations of the Schwinger model and selected quantum spin models  

E-Print Network (OSTI)

Numerical investigations of the XY model, the Heisenberg model and the J-J' Heisenberg model are conducted, using the exact diagonalisation, the numerical renormalisation and the density matrix renormalisation group approach. The low-lying energy levels are obtained and finite size scaling is performed to estimate the bulk limit values. The results are found to be consistent with the exact values. The DMRG results are found to be most promising. The Schwinger model is also studied using the exact diagonalisation and the strong coupling expansion. The massless, the massive model and the model with a background electric field are explored. Ground state energy, scalar and vector particle masses and order parameters are examined. The achieved values are observed to be consistent with previous results and theoretical predictions. Path to the future studies is outlined.

Marcin Szyniszewski

2013-03-03T23:59:59.000Z

52

Numerical Modeling of Orographically Forced Postfrontal Rain  

Science Conference Proceedings (OSTI)

A nonhydrostatic mesoscale model is used to simulate the dynamics and microphysics of postfrontal flow in the mountainous region of southeastern Australia. The aim of the paper is to determine if it is possible to use 2D models to simulate the ...

Deborah J. Abbs; Jørgen B. Jensen

1993-01-01T23:59:59.000Z

53

Performance of NMC's Regional Models  

Science Conference Proceedings (OSTI)

This paper details the performance characteristics of the two regional dynamical models used at the National Meteorological Center to forecast for North America. Strengths and weaknesses of these models—the limited-area fine-mesh (LFM) model and ...

Norman W. Junker; James E. Hoke; Richard H. Grumm

1989-09-01T23:59:59.000Z

54

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

55

A Lightning Parameterization for Numerical Cloud Models  

Science Conference Proceedings (OSTI)

A new lightning parameterization has been developed to enable cloud models to simulate the location and structure of individual lightning flashes more realistically. To do this, three aspects of previous parameterizations have been modified: 1) ...

Donald R. MacGorman; Jerry M. Straka; Conrad L. Ziegler

2001-03-01T23:59:59.000Z

56

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

57

A Numerical Study of Cirrus Clouds. Part I: Model Description  

Science Conference Proceedings (OSTI)

This article, the first of a two-part series, presents a detailed description of a two-dimensional numerical cloud model directed toward elucidating the physical processes governing the evolution of cirrus clouds. The two primary scientific ...

Hui-Chun Liu; Pao K. Wang; Robert E. Schlesinger

2003-04-01T23:59:59.000Z

58

Numerical Modeling of the Atmosphere with an Isentropic Vertical Coordinate  

Science Conference Proceedings (OSTI)

In constructing a numerical model of the atmosphere, we must choose an appropriate vertical coordinate. Among the various possibilities, isentropic vertical coordinates such as the ?-coordinate seem to have the greatest potential, in spite of the ...

Yueh-Jiuan G. Hsu; Akio Arakawa

1990-10-01T23:59:59.000Z

59

Numerical Modeling Studies of a Process of Lee Cyclogenesis  

Science Conference Proceedings (OSTI)

A process of lee cyclogenesis associated with backsheared baroclinic flow is studied using a fully nonlinear, primitive equation numerical model. A region of low pressure and a narrow baroclinic zone develop to the southwest of the mountain in ...

Yuh-Lang Lin; Donald J. Perkey

1989-12-01T23:59:59.000Z

60

Energy Trapping near the Equator in a Numerical Ocean Model  

Science Conference Proceedings (OSTI)

The trapped equatorial standing modes described theoretically by Gent (1979) are reproduced in a single vertical-mode numerical ocean model. integrations are carried out in domains whose longitudinal extents are characteristic of the widths of ...

Peter R. Gent; Albert J. Semtner Jr.

1980-06-01T23:59:59.000Z

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.


61

Two-Time-Step Oscillations in Numerical Weather Prediction Models  

Science Conference Proceedings (OSTI)

Spurious, nonamplifying, two-time-step oscillations are present in several numerical models of the atmosphere where the vertical diffusion is parameterized using a nonlinear diffusion equation. The problems become particularly pronounced when the ...

Ulla Hammarstrand

1997-12-01T23:59:59.000Z

62

Numerical Modeling of Gravity Wave Generation by Deep Tropical Convection  

Science Conference Proceedings (OSTI)

Although convective clouds are known to generate internal gravity waves, the mechanisms responsible are not well understood. The present study seeks to clarify the dynamics of wave generation using a high-resolution numerical model of deep ...

Todd P. Lane; Michael J. Reeder; Terry L. Clark

2001-05-01T23:59:59.000Z

63

Free Planetary Waves in Finite-Difference Numerical Models  

Science Conference Proceedings (OSTI)

The effects of spatial finite-differencing, viscosity and diffusion on unbounded planetary waves in numerical models are investigated using a quasi-geostrophic approximation to the midlatitude, ?-plane, shallow-water equations. The two-...

Roxana C. Wajsowicz

1986-04-01T23:59:59.000Z

64

An Eddy Resolving Numerical Model of the Ventilated Thermocline  

Science Conference Proceedings (OSTI)

A three-dimensional, primitive equation numerical model is used to study the effects of mesoscale eddies within the subtropical thermocline. Solutions are obtained for an ocean bounded by idealized topography are driven by simple wind and ...

Michael D. Cox

1985-10-01T23:59:59.000Z

65

Geothermal: Sponsored by OSTI -- A numerical model ofhydro-thermo...  

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

A numerical model of hydro-thermo-mechanical coupling in a fractured rock mass Geothermal Technologies Legacy Collection HelpFAQ | Site Map | Contact Us | Admin Log On HomeBasic...

66

Gulf of Mexico numerical model. Project summary  

DOE Green Energy (OSTI)

An efficient three-dimensional, time dependent prognostic model of the Gulf of Mexico has been developed. The model is driven by winds and surface heat flux derived from climatological, atmospheric surface data, the result of an intensive data analysis study. Mean velocity, temperature, salinity, turbulence kinetic energy and turbulence macroscale are the prognostic variables. Lateral boundary conditions for temperature and salinity and geostrophically derived velocity at the Straits of Yucatan and Florida are obtained from climatological ocean data. An analytical second moment turbulence closure scheme embedded within the model provides realistic surface mixed layer dynamics. Free surface elevation distributions are calculated with an algorithm which calculates the external (tidal) mode separately from the internal mode. The external mode, an essentially two-dimensional calculation, requires a short integrating timestep whereas the more costly, three-dimensional, internal mode can be executed with a long step. The result is a fully three-dimensional code which includes a free surface at no sacrifice in computer cost compared to rigid lid models.

Blumberg, A. F.; Mellor, G. L.; Herring, H. J.

1981-02-01T23:59:59.000Z

67

Mathematical Models in Landscape Ecology: Stability Analysis and Numerical Tests  

Science Conference Proceedings (OSTI)

In the present paper a review of some mathematical models for the ecological evaluation of environmental systems is considered. Moreover a new model, capable to furnish more detailed information at the level of landscape units, is proposed. Numerical ... Keywords: 34D05, 92F05, Landscape ecology, Mathematical models, Stability analysis

Federica Gobattoni; Giuliana Lauro; Roberto Monaco; Raffaele Pelorosso

2013-06-01T23:59:59.000Z

68

A Numerical Study of Water Injection on Transonic Compressor Rotor Performance.  

E-Print Network (OSTI)

??In this study, numerical simulations of two-phase flow in a transonic compressor rotor (NASA Rotor 37) were performed. Both flow and droplets governing equations were… (more)

Szabo, Istvan

2008-01-01T23:59:59.000Z

69

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

70

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

E-Print Network (OSTI)

of numerical weather prediction solar irradiance forecasts of numerical weather prediction for intra?day solar numerical weather prediction model for solar irradiance 

Mathiesen, Patrick; Collier, Craig; Kleissl, Jan

2013-01-01T23:59:59.000Z

71

Judging Air Quality Model Performance  

Science Conference Proceedings (OSTI)

Under the direction of the AMS Steering Committee for the EPA Cooperative Agreement on air quality modeling, a small group of scientists was convened to review and recommend procedures to evaluate the performance of air quality models. Particular ...

Douglas G. Fox

1981-05-01T23:59:59.000Z

72

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

73

Numerical predictions of railgun performance including the effects of ablation and arc drag  

SciTech Connect

Thermal radiation from plasma armatures in railguns may cause vaporization and partial ionization of the rail and insulator materials. This causes an increase in mass of the arc, which has an adverse effect on projectile velocity. Viscous drag on the arc also has a deleterious effect, particularly at high velocities. These loss mechanisms are modeled in the Los Alamos Railgun Estimator code. Simulations were performed and numerical results were compared with experimental data for a wide range of tests performed at the Los Alamos and Lawrence Livermore National Laboratories, the Ling Temco Vought Aerospace and Defense Company, and the Center for Electromechanics at the University of Texas at Austin. The effects of ablation and arc drag on railgun performance are discussed. Parametric studies illustrate the effects of some design parameters on projectile velocity and launcher efficiency. Some strategies for reducing the effects of ablation are proposed.

Schnurr, N.M.; Kerrisk, J.F.; Parker, J.V.

1986-01-01T23:59:59.000Z

74

NUMERICAL FLOW AND TRANSPORT SIMULATIONS SUPPORTING THE SALTSTONE FACILITY PERFORMANCE ASSESSMENT  

SciTech Connect

The Saltstone Disposal Facility Performance Assessment (PA) is being revised to incorporate requirements of Section 3116 of the Ronald W. Reagan National Defense Authorization Act for Fiscal Year 2005 (NDAA), and updated data and understanding of vault performance since the 1992 PA (Cook and Fowler 1992) and related Special Analyses. A hybrid approach was chosen for modeling contaminant transport from vaults and future disposal cells to exposure points. A higher resolution, largely deterministic, analysis is performed on a best-estimate Base Case scenario using the PORFLOW numerical analysis code. a few additional sensitivity cases are simulated to examine alternative scenarios and parameter settings. Stochastic analysis is performed on a simpler representation of the SDF system using the GoldSim code to estimate uncertainty and sensitivity about the Base Case. This report describes development of PORFLOW models supporting the SDF PA, and presents sample results to illustrate model behaviors and define impacts relative to key facility performance objectives. The SDF PA document, when issued, should be consulted for a comprehensive presentation of results.

Flach, G.

2009-02-28T23:59:59.000Z

75

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

76

A Numerical Model for Prediction of Road Temperature and Ice  

Science Conference Proceedings (OSTI)

A numerical model for the prediction of road temperature and ice has been tested on data from a Danish road station. The model is based on the solution of the equation of heat conduction in the ground and the surface energy-balance equation.

Bent H. Sass

1992-12-01T23:59:59.000Z

77

Introduction Application of numerical models of ground water flow  

E-Print Network (OSTI)

Introduction Application of numerical models of ground water flow almost always involves some sort (Yeh 1986; Poeter and Hill 1997; Hill et al. 1998). Other data beside hydraulic head have been used in calibration of ground water models, including rates of ground water exchange with streams and other surface

Saiers, James

78

The geomagnetic secularvariation timescale in observations and numerical dynamo models  

E-Print Network (OSTI)

The geomagnetic secularvariation timescale in observations and numerical dynamo models Florian March 2011; published 5 May 2011. [1] The knowledge of the spatial power spectra of the main geomagnetic for recent satellite field models. In the broader context of geomagnetic data assimilation, tSV could provide

Aubert, Julien

79

Methodology for updating numerical predictions of excavation performance  

E-Print Network (OSTI)

Due to the usual limitations in site investigations and measurements of soil properties, simplified constitutive models are routinely used in geotechnical analyses for the design of excavation support systems. However, ...

Corral Jofré, Gonzalo Andrés

2013-01-01T23:59:59.000Z

80

A Model Comparison: Numerical Simulations of the North and Equatorial Atlantic Oceanic Circulation in Depth and Isopycnic Coordinates  

Science Conference Proceedings (OSTI)

A series of medium-resolution (1°) numerical simulations for the equatorial and North Atlantic basin have been performed with two primitive equation models, one employing depth and the other density as the vertical coordinate. The models have ...

Eric P. Chassignet; Linda T. Smith; Rainer Bleck; Frank O. Bryan

1996-09-01T23:59:59.000Z

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.


81

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

82

Numerical modeling and experimental testing of a solar grill  

SciTech Connect

The sun provides a free, nonpolluting and everlasting source of energy. Considerable research has been carried out to utilize solar energy for purposes such as water heating, high temperature ovens, and conversion to electrical energy. One of the interesting forms for utilizing solar energy is cooking. The main disadvantage of solar energy systems has been the low efficiency attained in most of its practical applications. It is expected, however, that due to continuing decreases in the availability of other energy sources such as oil and coal, along with the safety problems associated with nuclear energy, man's need for utilization of solar energy will increase, thus leading him to find the ways and means to develop adequate and efficient solar-powered systems. In camps, where tents are used to accommodate people, cooking is done via conventional gas stoves. This usually takes place in extremely crowded areas which become highly fireprone. Solar oven cookers seem to be a viable alternative considering both economy and safety. Among the various forms of solar cookers, the oven-type solar cooker is known to be the best in terms of efficiency. One of the most practical and efficient forms of solar oven cookers is the outdoor portable solar grill (Bar-B-Q), developed by Khalifa et al. The solar grill is a light and portable unit that utilizes solar energy to grill meat. One of the best types of grilling with this cooker is the well-known Shish Kebab or Bar-B-Q. A detailed description for the design of the solar grill is provided as follows. This paper is aimed at providing experimental results and formulating a numerical model for the solar grill. Results of the two approaches are then compared to verify the validity of the numerical simulation. An experimental and theoretical investigation was conducted on the solar grill in order to study the factors that affect its design and performance.

Olwi, I.; Khalifa, A. (King Abdulaziz Univ., Jeddah (Saudi Arabia))

1993-02-01T23:59:59.000Z

83

Numerical models for the evaluation of geothermal systems  

DOE Green Energy (OSTI)

We have carried out detailed simulations of various fields in the USA (Bada, New Mexico; Heber, California); Mexico (Cerro Prieto); Iceland (Krafla); and Kenya (Olkaria). These simulation studies have illustrated the usefulness of numerical models for the overall evaluation of geothermal systems. The methodology for modeling the behavior of geothermal systems, different approaches to geothermal reservoir modeling and how they can be applied in comprehensive evaluation work are discussed.

Bodvarsson, G.S.; Pruess, K.; Lippmann, M.J.

1986-08-01T23:59:59.000Z

84

Near-fault earthquake ground motion prediction by a high-performance spectral element numerical code  

Science Conference Proceedings (OSTI)

Near-fault effects have been widely recognised to produce specific features of earthquake ground motion, that cannot be reliably predicted by 1D seismic wave propagation modelling, used as a standard in engineering applications. These features may have a relevant impact on the structural response, especially in the nonlinear range, that is hard to predict and to be put in a design format, due to the scarcity of significant earthquake records and of reliable numerical simulations. In this contribution a pilot study is presented for the evaluation of seismic ground-motions in the near-fault region, based on a high-performance numerical code for 3D seismic wave propagation analyses, including the seismic fault, the wave propagation path and the near-surface geological or topographical irregularity. For this purpose, the software package GeoELSE is adopted, based on the spectral element method. The set-up of the numerical benchmark of 3D ground motion simulation in the valley of Grenoble (French Alps) is chosen to study the effect of the complex interaction between basin geometry and radiation mechanism on the variability of earthquake ground motion.

Paolucci, Roberto [Department of Structural Engineering, Politecnico di Milano P.za Leonardo da Vinci 32, 20133, Milano (Italy); Stupazzini, Marco [Department of Structural Engineering, Politecnico di Milano P.za Leonardo da Vinci 32, 20133, Milano (Italy); EUCENTRE, v. Ferrata 1, Pavia (Italy)

2008-07-08T23:59:59.000Z

85

Forecasting the Skill of a Regional Numerical Weather Prediction Model  

Science Conference Proceedings (OSTI)

It is demonstrated that the skill of short-term regional numerical forecasts can be predicted on a day-to-day basis. This was achieved by using a statistical regression scheme with the model forecast errors (MFE) as the predictands and the ...

L. M. Leslie; K. Fraedrich; T. J. Glowacki

1989-03-01T23:59:59.000Z

86

Numerical Ocean Prediction Models—Goal for the 1980s  

Science Conference Proceedings (OSTI)

Based on the experience of numerical weather prediction during the 1950s and 1960s as a model, a case is presented for the development of an ocean prediction capability during the 1980s. Examples selected from recent research at the Naval ...

Russell L. Elsberry; Roland W. Garwood Jr.

1980-12-01T23:59:59.000Z

87

Numerical Discretization of Rotated Diffusion Operators in Ocean Models  

Science Conference Proceedings (OSTI)

A method to improve the behavior of the numerical discretization of a rotated diffusion operator such as, for example, the isopycnal diffusion parameterization used in large-scale ocean models based on the so-called z-coordinate system is ...

J-M. Beckers; H. Burchard; E. Deleersnijder; P. P. Mathieu

2000-08-01T23:59:59.000Z

88

Numerical Modeling of Internal Tide Generation along the Hawaiian Ridge  

Science Conference Proceedings (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

89

The Free Kelvin Wave in Finite-Difference Numerical Models  

Science Conference Proceedings (OSTI)

The effects of viscosity and finite- differencing on free Kelvin waves in numerical models (which employ the Arakawa B- or C-grid difference schemes) are investigated using the f-plane shallow-water equations with offshore finite-difference grids,...

William W. Hsieh; Michael K. Davey; Roxana C. Wajsowicz

1983-08-01T23:59:59.000Z

90

Thesis A Numerical Model of Hydro-Thermo- Mechanical Coupling...  

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

1 31 53-T Thesis A Numerical Model of Hydro-Thermo- Mechanical Coupling in a Fractured Rock Mass ECEIVED Los Alamos N A T I O N A L L A B O R A T O R Y Los Alamos National...

91

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

92

Performance and numerical accuracy evaluation of heterogeneous multicore systems for Krylov orthogonal basis computation  

Science Conference Proceedings (OSTI)

We study the numerical behavior of heterogeneous systems such as CPU with GPU or IBM Cell processors for some orthogonalization processes. We focus on the influence of the different floating arithmetic handling of these accelerators with Gram-Schmidt ... Keywords: numerical algorithms for CS&E, parallel and distributed computing, performance analysis

Jérôme Dubois; Christophe Calvin; Serge Petiton

2010-06-01T23:59:59.000Z

93

Air Conditioner Compressor Performance Model  

SciTech Connect

During the past three years, the Western Electricity Coordinating Council (WECC) Load Modeling Task Force (LMTF) has led the effort to develop the new modeling approach. As part of this effort, the Bonneville Power Administration (BPA), Southern California Edison (SCE), and Electric Power Research Institute (EPRI) Solutions tested 27 residential air-conditioning units to assess their response to delayed voltage recovery transients. After completing these tests, different modeling approaches were proposed, among them a performance modeling approach that proved to be one of the three favored for its simplicity and ability to recreate different SVR events satisfactorily. Funded by the California Energy Commission (CEC) under its load modeling project, researchers at Pacific Northwest National Laboratory (PNNL) led the follow-on task to analyze the motor testing data to derive the parameters needed to develop a performance models for the single-phase air-conditioning (SPAC) unit. To derive the performance model, PNNL researchers first used the motor voltage and frequency ramping test data to obtain the real (P) and reactive (Q) power versus voltage (V) and frequency (f) curves. Then, curve fitting was used to develop the P-V, Q-V, P-f, and Q-f relationships for motor running and stalling states. The resulting performance model ignores the dynamic response of the air-conditioning motor. Because the inertia of the air-conditioning motor is very small (H<0.05), the motor reaches from one steady state to another in a few cycles. So, the performance model is a fair representation of the motor behaviors in both running and stalling states.

Lu, Ning; Xie, YuLong; Huang, Zhenyu

2008-09-05T23:59:59.000Z

94

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

95

Physical and Numerical Models of Pore-Scale Trapping of CO2  

Science Conference Proceedings (OSTI)

Numerical simulations of deep geological carbon sequestration are being used to design field-scale implementations, predict their long-term performance, and evaluate associated risks. However, conventional field-scale simulators are unable to explicitly resolve the pore-scale processes that exert significant control on the migration and fate of supercritical CO2 in the subsurface. A combination of physical and numerical experiments with explicit pore-scale resolution are being performed in order to identify conditions under which continuum model approximations may fail, and to propose alternative simulation approaches that can be used in such cases.

Scheibe, Timothy D.; Tartakovsky, Alexandre M.; Bandara, Uditha C.; Palmer, Bruce J.; Oostrom, Martinus; Zhang, Changyong; Bonneville, Alain HR

2011-11-18T23:59:59.000Z

96

Integrating Numerical Computation into the Modeling Instruction Curriculum  

E-Print Network (OSTI)

We describe a way to introduce physics high school students with no background in programming to computational problem-solving experiences. Our approach builds on the great strides made by the Modeling Instruction reform curriculum. This approach emphasizes the practices of "Developing and using models" and "Computational thinking" highlighted by the NRC K-12 science standards framework. We taught 9th-grade students in a Modeling-Instruction-based physics course to construct computational models using the VPython programming environment. Numerical computation within the Modeling Instruction curriculum provides coherence among the curriculum's different force and motion models, links the various representations which the curriculum employs, and extends the curriculum to include real-world problems that are inaccessible to a purely analytic approach.

Caballero, Marcos D; Aiken, John M; Douglas, Scott S; Scanlon, Erin M; Thoms, Brian; Schatz, Michael F

2012-01-01T23:59:59.000Z

97

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

98

Mapping Frost-Sensitive Areas with a Three-Dimensional Local-Scale Numerical Model. Pad II: Comparison with Observations  

Science Conference Proceedings (OSTI)

A three-dimensional numerical model was developed to predict the microclimate near the ground surface of local-scale domains during radiative frost events. Its performances are compared with an observational topo-climatological survey of minimum ...

R. Avissar; Y. Mahrer

1988-04-01T23:59:59.000Z

99

Numerical modeling of injection experiments at The Geysers  

DOE Green Energy (OSTI)

Data from injection experiments in the southeast Geysers are presented that show strong interference (both negative and positive) with a neighboring production well. Conceptual and numerical models are developed that explain the negative interference (decline of production rate) in terms of heat transfer limitations and water-vapor relative permeability effects. Recovery and over-recovery following injection shut-in are attributed to boiling of injected fluid, with heat of vaporization provided by the reservoir rocks.

Pruess, K. [Lawrence Berkeley Lab., CA (United States); Enedy, S. [Northern California Power Agency, Middletown, CA (United States)

1993-01-01T23:59:59.000Z

100

ASSIMILATION OF DOPPLER RADAR DATA INTO NUMERICAL WEATHER MODELS  

Science Conference Proceedings (OSTI)

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

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

Thermoinertial bouncing of a relativistic collapsing sphere: A numerical model  

Science Conference Proceedings (OSTI)

We present a numerical model of a collapsing radiating sphere, whose boundary surface undergoes bouncing due to a decreasing of its inertial mass density (and, as expected from the equivalence principle, also of the 'gravitational' force term) produced by the 'inertial' term of the transport equation. This model exhibits for the first time the consequences of such an effect, and shows that under physically reasonable conditions this decreasing of the gravitational term in the dynamic equation may be large enough as to revert the collapse and produce a bouncing of the boundary surface of the sphere.

Herrera, L.; Di Prisco, A.; Barreto, W. [Centro de Fisica Teorica y Computacional, Facultad de Ciencias, Universidad Central de Venezuela, Caracas (Venezuela); Centro de Fisica Fundamental, Facultad de Ciencias, Universidad de los Andes, Merida (Venezuela)

2006-01-15T23:59:59.000Z

102

Numerical Model for Conduction-Cooled Current Lead Heat Loads  

SciTech Connect

Current leads are utilized to deliver electrical power from a room temperature junction mounted on the vacuum vessel to a superconducting magnet located within the vacuum space of a cryostat. There are many types of current leads used at laboratories throughout the world; however, conduction-cooled current leads are often chosen for their simplicity and reliability. Conduction-cooled leads have the advantage of using common materials, have no superconducting/normal state transition, and have no boil-off vapor to collect. This paper presents a numerical model for conduction-cooled current lead heat loads. This model takes into account varying material and fluid thermal properties, varying thicknesses along the length of the lead, heat transfer in the circumferential and longitudinal directions, electrical power dissipation, and the effect of thermal intercepts. The model is validated by comparing the numerical model results to ideal cases where analytical equations are valid. In addition, the XFEL (X-Ray Free Electron Laser) prototype current leads are modeled and compared to the experimental results from testing at DESY's XFEL Magnet Test Stand (XMTS) and Cryomodule Test Bench (CMTB).

White, M.J.; Wang, X.L.; /Fermilab; Brueck, H.D.; /DESY

2011-06-10T23:59:59.000Z

103

Numerical model to characterize the thermal comfort in new ecodistricts: methodology and validation through the canyon street case  

Science Conference Proceedings (OSTI)

In built-up areas, the urban structures affect the radiative and thermal environment. The numerical simulation models provide informations about urban thermal performance for many ranges of urban configurations. This paper presents a validation of a ... Keywords: CFD model, building heat transfers, coupling model, street canyon, thermo-radiative model

Khaled Athamena; Jean Francois Sini; Julien Guilhot; Jerome Vinet; Maeva Sabre; Jean-Michel Rosant

2011-01-01T23:59:59.000Z

104

Numerical model to characterize the thermal comfort in new eco-districts: methodology and validation through the canyon street case  

Science Conference Proceedings (OSTI)

In built-up areas, the urban structures affect the radiative and thermal environment. The numerical simulation models provide informations about urban thermal performance for many ranges of urban configurations. This paper presents a validation of a ... Keywords: CFD model, building heat transfers, coupling model, street canyon, thermo-radiative model

Khaled Athamena; Jean Francois Sini; Julien Guilhot; Jerome Vinet; Maeva Sabre; Jean-Michel Rosant

2011-01-01T23:59:59.000Z

105

NUMERICAL NEAR-STALL PERFORMANCE PREDICTION FOR A LOW SPEED SINGLE STAGE COMPRESSOR.  

E-Print Network (OSTI)

??Computational Fluid Dynamics is used to model turbomachinery compressor performance throughout the entire operating range. While it can be very accurate for peak performance calculations,… (more)

SHUEY, MICHAEL G.E.

2005-01-01T23:59:59.000Z

106

Optimal numerical realization of the energy balance equation for wind wave models  

Science Conference Proceedings (OSTI)

The optimal numerical realization of the energy balance equation in wind wave models is proposed. The scheme is separated into two parts: the numerical source term integration and the energy propagation numerical realization. The first one is based on ...

Igor V. Lavrenov

2003-06-01T23:59:59.000Z

107

A Split Explicit Reformulation of the Regional Numerical Weather Prediction Model of the Japan Meteorological Agency  

Science Conference Proceedings (OSTI)

The split explicit integration scheme for numerical weather prediction models is employed in a version of the regional numerical weather prediction model of the Japan Meteorological Agency. The finite-difference scheme of the model is designed in ...

Dean G. Duffy

1981-05-01T23:59:59.000Z

108

Irradiation Performance of Advanced and Model Alloys  

Science Conference Proceedings (OSTI)

Mar 14, 2012 ... Mechanical Performance of Materials for Current and Advanced Nuclear Reactors: Irradiation Performance of Advanced and Model Alloys

109

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

110

Numerical Modeling of Complex Porous Media For Borehole Applications  

E-Print Network (OSTI)

The diffusion/relaxation behavior of polarized spins of pore filling fluid, as often probed by NMR relaxometry, is widely used to extract information on the pore-geometry. Such information is further interpreted as an indicator of the key transport property of the formation in the oil industry. As the importance of reservoirs with complex pore geometry grows, so does the need for deeper understanding of how these properties are inter-related. Numerical modeling of relevant physical processes using a known pore geometry promises to be an effective tool in such endeavor. Using a suite of numerical techniques based on random-walk (RW) and Lattice-Boltzmann (LB) algorithms, we compare sandstone and carbonate pore geometries in their impact on NMR and flow properties. For NMR relaxometry, both laboratory measurement and simulation were done on the same source to address some of the long-standing issues in its borehole applications. Through a series of "numerical experiments" in which the interfacial relaxation properties of the pore matrix is varied systematically, we study the effect of a variable surface relaxivity while fully incorporating the complexity of the pore geometry. From combined RW and LB simulations, we also obtain diffusion-convection propagator and compare the result with experimental and network-simulation counterparts.

Seungoh Ryu; Weishu Zhao; Gabriela Leu; Philip M. Singer; Hyung Joon Cho; Youngseuk Keehm

2009-08-13T23:59:59.000Z

111

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

112

Numerical and Experimental Analysis of Multi-Stage Axial Turbine Performance at Design and Off-Design Conditions  

E-Print Network (OSTI)

Computational fluid dynamics or CFD isan importanttool thatis used at various stages in the design of highly complex turbomachinery such as compressorand turbine stages that are used in land and air based power generation units. The ability of CFD to predict the performance characteristics of a specific blade design is challenged by the need to use various turbulence models to simulate turbulent flows as well as transition models to simulate laminar to turbulent transition that can be observed in various turbomachinery designs. Moreover, CFD is based on numerically solving highly complex differential equations, which through the use of a grid to discretize the geometry introduces numerical errors. Allthese factors combine to challenge CFD’s role as a predictor of blade performance. It has been generallyfound that CFD in its current state of the art is best used to compare between various design points and not as a pure predictor of performances. In this study the capability of CFD, and turbulence modeling, in turbomachinery based geometry is assessed.Three different blade designs are tested, that include an advanced two-stage turbine blade design, a three stage 2D or cylindrical design and finally a three stage bowed stator and rotor design. Allcases were experimentally tested at the Texas A&Muniversity Turbomachinery Performance and Flow Research Laboratory (TPFL).In all cases CFD provided good insights into fundamental turbomachinery flow physics, showing the expected improvement from using 2D cylindrical blades to 3D bowed blade designs in abating the secondary flow effects which are dominant loss generators.However, comparing experimentally measured performance results to numerically predicted shows a clear deficiency, where the CFD overpredicts performance when compared to experimentallyobtained data, largely underestimating the various loss mechanisms. In a relative sense, CFD as a tool allows the user to calculate the impact a new feature or change can have on a baseline design. CFD will also provide insight into what are the dominant physics that explain why a change can provide an increase or decrease in performance. Additionally,as part of this study, one of the main factors that affect the performance of modern turbomachinery is transition from laminar to turbulent flow.Transition is an influential phenomena especially in high pressure turbines, and is sensitive to factors such asupstream incidentwake frequency and turbulence intensity.A model experimentally developed, is implemented into a CFD solver and compared to various test results showing greater capability in modeling the effects of reduced frequency on the transition point and transitional flow physics. This model is compared to industry standard models showing favorable prediction performance due to its abilityto account for upstream wake effects which most current model are unable to account for.

Abdelfattah, Sherif Alykadry

2013-08-01T23:59:59.000Z

113

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

114

Progress report on LBL's numerical modeling studies on Cerro Prieto  

DOE Green Energy (OSTI)

An exploitation model of the Cerro Prieto geothermal system is needed to assess the energy capacity of the field, estimate its productive lifetime and develop an optimal reservoir management plan. The model must consider the natural state (i.e., pre-exploitation) conditions of the system and be able to predict changes in the reservoir thermodynamic conditions (and fluid chemistry) in response to fluid production (and injection). This paper discusses the results of a three-dimensional numerical simulation of the natural state conditions of the Cerro Prieto field and compares computed and observed pressure and temperature/enthalpy changes for the 1973--1987 production period. 16 refs., 24 figs., 2 tabs.

Halfman-Dooley, S.E.; Lippman, M.J.; Bodvarsson, G.S.

1989-04-01T23:59:59.000Z

115

Numerical modeling of a true in situ oil shale retort  

DOE Green Energy (OSTI)

A numerical model has been developed to simulate the true in situ retorting process. The retort is assumed to be a low-porosity fractured bed composed of large seams of competent shale separated at intervals by open fractures. Kerogen and carbonate decomposition and char, oil, and gas combustion, as well as other reactions, are considered. In contrast to the results of rubbled-bed models, the retorting of seams thicker than one meter is characterized by incomplete retorting and significant oil combustion (10 to 40% of that retorted). The amount of shale retorted can, however, be maximized by proper control of air and steam injection rates, with the injected gas being optimally 40 to 50% steam. The oil available for recovery from a two meter seam can then be, for example, as high as 50% of Fischer Assay.

Tyner, C.E.; Hommert, P.J.

1979-01-01T23:59:59.000Z

116

A numerical model simulation of longshore transport for Galveston Island  

E-Print Network (OSTI)

The shoreline changes, deposition patterns, and longshore transport rates were calculated for the coast of Galveston Island using a numerical model simulation. The model only simulated changes due to waves creating longshore currents. East Beach showed a net accretion pattern, with erosion confined to the eastern section of the area. Large accretion was found near the first groin indicating transport from east to west. The groin field fluctuated with erosion and accretion, with a net gain of shoreline. The unprotected beach in front of the seawall eroded almost completely away. West Beach had a net loss of shoreline overall. This was largely due to the shoreline erosion found at San Luis Pass. The majority of West Beach was frequently unstable, fluctuating between erosion and accretion.

Gilbreath, Stephen Alexander

1995-01-01T23:59:59.000Z

117

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

118

Performance evaluation of an improved harmony search algorithm for numerical optimization: Melody Search (MS)  

Science Conference Proceedings (OSTI)

Melody Search (MS) Algorithm as an innovative improved version of Harmony Search optimization method, with a novel Alternative Improvisation Procedure (AIP) is presented in this paper. MS algorithm mimics performance processes of the group improvisation ... Keywords: Alternative improvisation procedure, Harmony search, Melody Search algorithm, Numerical optimization, Stochastic search methods

S. M. Ashrafi; A. B. Dariane

2013-04-01T23:59:59.000Z

119

Effects of Numerics on the Physics in a Third-Generation Wind-Wave Model  

Science Conference Proceedings (OSTI)

Numerical errors in third-generation ocean wave models can result in a misinterpretation of the physics in the model. Using idealized situations, it is shown that numerical errors significantly influence the initial growth, the response of wave ...

Hendrik L. Tolman

1992-10-01T23:59:59.000Z

120

Numeric modeling of fire suppression by organophosphorous inhibitors  

E-Print Network (OSTI)

Numerical calculations of the effect of organophosphorous inhibitor (CF3CH2O)3P and its mixtures with carbon dioxide on propane flames are carried out using the three dimensional Reynolds-averaged Navier-Stokes (RANS) equations in the low Mach number approximation. The k-e model of turbulence, the EDC combustion model and the weighted-sum-of-gray-gases model of radiation are used. The Westbrook global-kinetic scheme with fractional order of reaction was used for the calculation of chemical reaction rate of propane combustion. The empirical expression for the correction factor for the chemical reaction rate was used to model the effect of organophosphorous inhibitor no the reaction. Two series of test calculations for different values of the correction factor are carried out. Dependences of the minimum extinguishing concentration of the inhibitor per carbon dioxide volume concentration in the extinguishing mixtures were obtained. The results of test calculations are shown to agree reasonably with the experimen...

Makhviladze, G M; Zykov, A P

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.


121

CDIAC catalog of numeric data packages and computer model packages  

Science Conference Proceedings (OSTI)

The Carbon Dioxide Information Analysis Center acquires, quality-assures, and distributes to the scientific community numeric data packages (NDPs) and computer model packages (CMPs) dealing with topics related to atmospheric trace-gas concentrations and global climate change. These packages include data on historic and present atmospheric CO{sub 2} and CH{sub 4} concentrations, historic and present oceanic CO{sub 2} concentrations, historic weather and climate around the world, sea-level rise, storm occurrences, volcanic dust in the atmosphere, sources of atmospheric CO{sub 2}, plants` response to elevated CO{sub 2} levels, sunspot occurrences, and many other indicators of, contributors to, or components of climate change. This catalog describes the packages presently offered by CDIAC, reviews the processes used by CDIAC to assure the quality of the data contained in these packages, notes the media on which each package is available, describes the documentation that accompanies each package, and provides ordering information. Numeric data are available in the printed NDPs and CMPs, in CD-ROM format, and from an anonymous FTP area via Internet. All CDIAC information products are available at no cost.

Boden, T.A. [Oak Ridge National Lab., TN (United States). Carbon Dioxide Information Analysis Center; O`Hara, F.M. Jr. [O`Hara (Fred M., Jr.), Oak Ridge, TN (US); Stoss, F.W. [Univ. of Tennessee, Knoxville, TN (US). Energy, Environment, and Resources Center

1993-05-01T23:59:59.000Z

122

Coupling geological and numerical models to simulate groundwater flow and contaminant transport in fractured media  

Science Conference Proceedings (OSTI)

A new modeling approach is presented to improve numerical simulations of groundwater flow and contaminant transport in fractured geological media. The approach couples geological and numerical models through an intermediate mesh generation phase. As ... Keywords: Fractures, Geomodel, Influence coefficient technique, Numerical modeling, Tetrahedra

Daniela Blessent; René Therrien; Kerry MacQuarrie

2009-09-01T23:59:59.000Z

123

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

124

Numerical Modeling of Hailstorms and Hailstone Growth. Part I: Preliminary Model Verification and Sensitivity Tests  

Science Conference Proceedings (OSTI)

This paper is the first in a three part series describing numerical simulations of hailstorms and hailstone growth using a two-dimensional, time-dependent cloud model. In this model. cloud water, cloud ice and rain are treated via standard ...

R. D. Farley; H. D. Orville

1986-12-01T23:59:59.000Z

125

Passive millimeter-wave retrieval of global precipitation utilizing satellites and a numerical weather prediction model  

E-Print Network (OSTI)

This thesis develops and validates the MM5/TBSCAT/F([lambda]) model, composed of a mesoscale numerical weather prediction (NWP) model (MM5), a two-stream radiative transfer model (TBSCAT), and electromagnetic models for ...

Surussavadee, Chinnawat

2007-01-01T23:59:59.000Z

126

Numerical modeling of the wind flow over a transverse dune  

E-Print Network (OSTI)

Transverse dunes, which form under unidirectional winds and have fixed profile in the direction perpendicular to the wind, occur on all celestial objects of our solar system where dunes have been detected. Here we perform a numerical study of the average turbulent wind flow over a transverse dune by means of computational fluid dynamics simulations. We find that the length of the zone of recirculating flow at the dune lee --- the {\\em{separation bubble}} --- displays a surprisingly strong dependence on the wind shear velocity, $u_{\\ast}$: it is nearly independent of $u_{\\ast}$ for shear velocities within the range between $0.2\\,$m$$s and $0.8\\,$m$$s but increases linearly with $u_{\\ast}$ for larger shear velocities. Our calculations show that transport in the direction opposite to dune migration within the separation bubble can be sustained if $u_{\\ast}$ is larger than approximately $0.39\\,$m$$s, whereas a larger value of $u_{\\ast}$ (about $0.49\\,$m$$s) is required to initiate this reverse transport.

Ascânio D. Araújo; Eric J. R. Parteli; Thorsten Poeschel; José S. Andrade Jr.; Hans J. Herrmann

2013-07-26T23:59:59.000Z

127

Lighting and Sustained Performance: Modeling Data-Entry Task Performance  

Science Conference Proceedings (OSTI)

This report describes an experiment undertaken to determine the effect of different lighting and print conditions on the sustained performance of a repetitive, self-paced, data-entry task. This research led to the development of an empirical model of task performance, the Data-Entry Task Performance (DETP) model, which can be used to quantify the amount of work done on a data-entry task in a fixed time for changes in illuminance, print size, and luminance contrast.

2000-04-13T23:59:59.000Z

128

Position paper: Characterising performance of environmental models  

Science Conference Proceedings (OSTI)

In order to use environmental models effectively for management and decision-making, it is vital to establish an appropriate level of confidence in their performance. This paper reviews techniques available across various fields for characterising the ... Keywords: Model development, Model evaluation, Model testing, Performance indicators, Sensitivity analysis

Neil D. Bennett; Barry F. W. Croke; Giorgio Guariso; Joseph H. A. Guillaume; Serena H. Hamilton; Anthony J. Jakeman; Stefano Marsili-Libelli; Lachlan T. H. Newham; John P. Norton; Charles Perrin; Suzanne A. Pierce; Barbara Robson; Ralf Seppelt; Alexey A. Voinov; Brian D. Fath; Vazken Andreassian

2013-02-01T23:59:59.000Z

129

Three-Dimensional Numerical Evaluation of Thermal Performance of Uninsulated Wall Assemblies: Preprint  

SciTech Connect

This study describes a detailed three-dimensional computational fluid dynamics modeling to evaluate the thermal performance of uninsulated wall assemblies accounting for conduction through framing, convection, and radiation. The model allows for material properties variations with temperature. Parameters that were varied in the study include ambient outdoor temperature and cavity surface emissivity. Understanding the thermal performance of uninsulated wall cavities is essential for accurate prediction of energy use in residential buildings. The results can serve as input for building energy simulation tools for modeling the temperature dependent energy performance of homes with uninsulated walls.

Ridouane, E. H.; Bianchi, M.

2011-11-01T23:59:59.000Z

130

Numerical Forecasting of Radiation Fog. Part I: Numerical Model and Sensitivity Tests  

Science Conference Proceedings (OSTI)

To improve the forecast of dense radiative fogs, a method has been developed using a one-dimensional model of the nocturnal boundary layer forced by the mesoscale fields provided by a 3D limited-area operational model. The 1D model involves a ...

Thierry Bergot; Daniel Guedalia

1994-06-01T23:59:59.000Z

131

An Open Boundary Condition for Numerical Coastal Circulation Models  

Science Conference Proceedings (OSTI)

Open boundaries (OBs) are usually unavoidable in numerical coastal circulation simulations. At OBs, an appropriate open boundary condition (OBC) is required so that outgoing waves freely pass to the exterior without creating reflections back into ...

Peifeng Ma; Ole Secher Madsen

2011-12-01T23:59:59.000Z

132

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 centrifugal compressor (LSCC). The LSCC was selected as a test compressor because of the experimental data available. The numerically simulated data was compared to the experimental data to validate the flow solver. The numerical results were in good agreement with the experimental. The second compressor simulated was a Honeywell turbopump centrifugal compressor (HCC). The HCC was simulated for three tip clearances at six wheel speeds. Six operating conditions were investigated at each tip clearance and wheel speed. The data obtained from the HCC simulations was used to investigate the effect of tip clearance on compressor performance. Specifically, the total-total pressure ratio, mass flow rate and adiabatic efficiencies were tracked to see how each were affected by an increasing tip clearance. The results show that as the tip clearance was increased, the total-total pressure ratio, mass flow rate and adiabatic efficiencies all decreased for the same static-total pressure ratio. The pressure differences and temperature differences, from the pressure side to the suction side of the blade, and the vorticity were all explored as possible causes of this reduced performance. The pressure proved to be the biggest impactor on performance. The increased tip clearance let more flow leak across the blade tip. The leakage flow tried to homogenize the pressure difference across the blade. The overall effect resulted in a much lower pressure difference. The temperature remained nearly the same as the tip clearance increased. The vorticity increased, but this was also a result of the increased tip leakage flow. To aid in total-total pressure ratio predictions, the results for the HCC were put into compressor maps.

Hoenninger, Corbett Reed

2001-01-01T23:59:59.000Z

133

The Maximum Intensity of Tropical Cyclones in Axisymmetric Numerical Model Simulations  

Science Conference Proceedings (OSTI)

An axisymmetric numerical model is used to evaluate the maximum possible intensity of tropical cyclones. As compared with traditionally formulated nonhydrostatic models, this new model has improved mass and energy conservation in saturated ...

George H. Bryan; Richard Rotunno

2009-06-01T23:59:59.000Z

134

An evaluation of tropical cyclone genesis forecasts from global numerical models  

Science Conference Proceedings (OSTI)

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

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

135

Laboratory–Numerical Model Comparisons of Flow over a Coastal Canyon  

Science Conference Proceedings (OSTI)

Different modeling approaches are applied to the same geophysical flow in order to assess the ability of laboratory models to provide useful benchmarks in the development of oceanic numerical models. The test case considered here—that of the flow ...

Nicolas Pérenne; Dale B. Haidvogel; Don L. Boyer

2001-02-01T23:59:59.000Z

136

An Evaluation of Tropical Cyclone Genesis Forecasts from Global Numerical Models  

Science Conference Proceedings (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

137

Heavy Tails: Performance Models and Scheduling Disciplines  

E-Print Network (OSTI)

Heavy Tails: Performance Models and Scheduling Disciplines Sindo N´u~nez-Queija based on joint ITC´u~nez-Queija CWI & TU/e #12;Heavy Tails: Performance Models and Scheduling Disciplines Part I ­ Introduction and Methodology Tales to tell: · traffic measurements and statistical analysis · traffic modeling · heavy

Núñez-Queija, Rudesindo

138

Parameterization of Convective Precipitation in Mesoscale Numerical Models: A Critical Review  

Science Conference Proceedings (OSTI)

Current approaches for incorporating cumulus convection into mesoscale numerical models are divided into three groups. The traditional approach utilizes cumulus parameterization at convectively unstable points and explicit (nonparameterized) ...

John Molinari; Michael Dudek

1992-02-01T23:59:59.000Z

139

Models of Photovoltaic Module Performance  

Science Conference Proceedings (OSTI)

An analysis of data collected over a three-year period at Pacific Gas and Electric Company's Photovoltaic Test Facility has enabled the prediction of photovoltaic (PV) module performance under conditions different from the test environment. The equations developed by PG&E provide a basis for rating photovoltaic modules and systems more accurately than in the past.

1988-09-01T23:59:59.000Z

140

Numerical modeling of a solid particle solar central receiver  

Science Conference Proceedings (OSTI)

The flow of air and particles and the heat transfer inside a solar heated, open cavity containing a falling cloud of 100 to 1000 micron solid particles have been studied. Two-way momentum and thermal coupling between the particles and the air is included in the analysis along with the effects of radiative transport within the particle cloud, among the cavity surfaces, and between the cloud and the surfaces. The flow field is assumed to be two dimensional with steady mean quantities. The PSI-Cell (particle source in cell) computer code is used to describe the gas-particle interaction. The method of discrete ordinates is used to obtain the radiative transfer within the cloud. The results include the velocity and temperature profiles of the particles and the air. In addition, the thermal performance of the solid particle solar receiver has been determined as a function of the following particle parameters: size, mass flow rate, absorptivity, and infrared scattering albedo. Other parameters which have been varied include the incident solar flux (both magnitude and distribution) and receiver size. A forced flow, applied across the cavity aperture, has also been investigated as a means of decreasing convective heat loss from the cavity. Comparison of the results from the model has been made with an experiment performed at the radiant heat facility in Albuquerque. The model has also been used to predict the entrainment of air and the decrease in particle drag which has been observed when measurements were made of particle velocity in a cloud of particles in free fall.

Evans, G.H.; Houf, W.G.; Greif, R.; Crowe, C.

1985-12-01T23:59:59.000Z

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.


141

Sensitivity of numerical dispersion modeling to explosive source parameters  

Science Conference Proceedings (OSTI)

The calculation of downwind concentrations from non-traditional sources, such as explosions, provides unique challenges to dispersion models. The US Department of Energy has assigned the Atmospheric Release Advisory Capability (ARAC) at the Lawrence Livermore National Laboratory (LLNL) the task of estimating the impact of accidental radiological releases to the atmosphere anywhere in the world. Our experience includes responses to over 25 incidents in the past 16 years, and about 150 exercises a year. Examples of responses to explosive accidents include the 1980 Titan 2 missile fuel explosion near Damascus, Arkansas and the hydrogen gas explosion in the 1986 Chernobyl nuclear power plant accident. Based on judgment and experience, we frequently estimate the source geometry and the amount of toxic material aerosolized as well as its particle size distribution. To expedite our real-time response, we developed some automated algorithms and default assumptions about several potential sources. It is useful to know how well these algorithms perform against real-world measurements and how sensitive our dispersion model is to the potential range of input values. In this paper we present the algorithms we use to simulate explosive events, compare these methods with limited field data measurements, and analyze their sensitivity to input parameters. 14 refs., 7 figs., 2 tabs.

Baskett, R.L. (EG and G Energy Measurements, Inc., Pleasanton, CA (USA)); Cederwall, R.T. (Lawrence Livermore National Lab., CA (USA))

1991-02-13T23:59:59.000Z

142

Decoupled overlapping grids for the numerical modeling of oil wells  

Science Conference Proceedings (OSTI)

Accurate computation of time-dependent well bore pressure is important in well test analysis - a branch of petroleum engineering where reservoir properties are estimated by comparing measured pressure responses at an oil well to results from a mathematical ... Keywords: Numerical well test analysis, Overlapping grids, Reservoir simulation

Nneoma Ogbonna; Dugald B. Duncan

2012-01-01T23:59:59.000Z

143

A reaction-based river/stream water quality model Part I: Model development and numerical schemes  

SciTech Connect

This paper presents the conceptual and mathematical development of a numerical model of sediment and reactive chemical transport in river/streams. The distribution of mobile suspended sediments and immobile bed sediments is controlled by hydrologic transport as well as erosion and deposition processes. The fate and transport of water quality constituents involving a variety of chemical and physical processes is mathematically described by a system of reaction equations for immobile constituents and advective-dispersive-reactive transport equations for constituents. To circumvent stiffness associated with equilibrium reactions, matrix decomposition is performed via Gauss-Jordan column reduction. After matrix decomposition, the system of water quality constituent reactive transport equations is transformed into a set of thermodynamic equations representing equilibrium reactions and a set of transport equations involving no equilibrium reactions. The decoupling of equilibrium and kinetic reactions enables robust numerical integration of the partial differential equations for non-equilibrium-variables. Solving non-equilibrium-variable transport equations instead of individual water quality constituent transport equations also reduces the number of PDEs. A variety of numerical methods are investigated for solving the mixed differential and algebraic equations. Two verification examples are compared with analytical solutions to demonstrate the correctness of the code and to illustrate the importance of employing application-dependent numerical methods to solve specific problems.

Zhang, Fan [ORNL; Gour-Tsyh, Yeh [University of Central Florida, Orlando; Parker, Jack C. [University of Tennessee, Knoxville (UTK); Jardine, Philip M [ORNL

2008-01-01T23:59:59.000Z

144

Summary of photovoltaic system performance models  

DOE Green Energy (OSTI)

The purpose of this study is to provide a detailed overview of photovoltaics (PV) performance modeling capabilities that have been developed during recent years for analyzing PV system and component design and policy issues. A set of 10 performance models have been selected which span a representative range of capabilities from generalized first-order calculations to highly specialized electrical network simulations. A set of performance modeling topics and characteristics is defined and used to examine some of the major issues associated with photovoltaic performance modeling. Next, each of the models is described in the context of these topics and characteristics to assess its purpose, approach, and level of detail. Then each of the issues is discussed in terms of the range of model capabilities available and summarized in tabular form for quick reference. Finally, the models are grouped into categories to illustrate their purposes and perspectives.

Smith, J. H.; Reiter, L. J.

1984-01-15T23:59:59.000Z

145

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

Science Conference Proceedings (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

146

Fractional Calculus in Hydrologic Modeling: A Numerical Perspective  

Science Conference Proceedings (OSTI)

Fractional derivatives can be viewed either as a handy extension of classical calculus or, more deeply, as mathematical operators defined by natural phenomena. This follows the view that the diffusion equation is defined as the governing equation of a Brownian motion. In this paper, we emphasize that fractional derivatives come from the governing equations of stable Levy motion, and that fractional integration is the corresponding inverse operator. Fractional integration, and its multi-dimensional extensions derived in this way, are intimately tied to fractional Brownian (and Levy) motions and noises. By following these general principles, we discuss the Eulerian and Lagrangian numerical solutions to fractional partial differential equations, and Eulerian methods for stochastic integrals. These numerical approximations illuminate the essential nature of the fractional calculus.

David A. Benson; Mark M. Meerschaert; Jordan Revielle

2012-01-01T23:59:59.000Z

147

Operational Convective-Scale Numerical Weather Prediction with the COSMO Model: Description and Sensitivities  

Science Conference Proceedings (OSTI)

Since April 2007, the numerical weather prediction model, COSMO (Consortium for Small Scale Modelling), has been used operationally in a convection-permitting configuration, named COSMO-DE, at the Deutscher Wetterdienst (DWD; German weather ...

Michael Baldauf; Axel Seifert; Jochen Förstner; Detlev Majewski; Matthias Raschendorfer; Thorsten Reinhardt

2011-12-01T23:59:59.000Z

148

Convective Building of a Pycnocline: A Two-Dimensional Nonhydrostatic Numerical Model  

Science Conference Proceedings (OSTI)

The convective building of a pycnocline is examined using a two-dimensional nonhydrostatic numerical model forced by a balanced salinity dipole (source and sink). Although the forcing fields are steady, the model develops oscillations that renew ...

David W. Pierce; Peter B. Rhines

1997-06-01T23:59:59.000Z

149

Numerical Investigations with a Hybrid Isentropic–Sigma Model. Part I: Normal-Mode Characteristics  

Science Conference Proceedings (OSTI)

In a validation experiment of a hybrid isentropic–sigma coordinate primitive equation model developed at the University of Wisconsin (the UW ??? model), an initial value technique is used to investigate numerically the normal-mode characteristics ...

R. Bradley Pierce; Fred M. Reames; Tom H. Zapotocny; Donald R. Johnson; Bart J. Wolf

1991-09-01T23:59:59.000Z

150

Localized Precipitation Forecasts from a Numerical Weather Prediction Model Using Artificial Neural Networks  

Science Conference Proceedings (OSTI)

Although the resolution of numerical weather prediction models continues to improve, many of the processes that influence precipitation are still not captured adequately by the scales of present operational models, and consequently precipitation ...

Robert J. Kuligowski; Ana P. Barros

1998-12-01T23:59:59.000Z

151

Cumulus Entrainment and Cloud Droplet Spectra: A Numerical Model within a Two-Dimensional Dynamical Framework  

Science Conference Proceedings (OSTI)

A simple numerical model designed to predict the evolution of cloud droplet spectra with special emphasis on the role of entrainment is developed for a case of nonprecipitating cloud. The model assumes that the cloud water mixing ratio at any ...

Jean-Louis Brenguier; Wojciech W. Grabowski

1993-01-01T23:59:59.000Z

152

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

Science Conference Proceedings (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

153

Numerical Model Simulations of a Mesoscale Gravity Wave Event: Sensitivity Tests and Spectral Analyses  

Science Conference Proceedings (OSTI)

This study presents numerical model experiments and spectral investigations involving a mesoscale gravity wave event. Its purposes are to determine the sensitivity of mesoscale gravity wave simulation to model configuration and physics and to ...

Jordan G. Powers

1997-08-01T23:59:59.000Z

154

Numerical Simulation of Organized Convection. Part I: Model Description and Preliminary Comparisons with Squall Line Observations  

Science Conference Proceedings (OSTI)

A numerical model designed for the simulations of mesoscale flows perturbed by deep convective clouds is discussed. It is based on the time dependent coupling between a three-dimensional nonhydrostatic mesoscale model and a quasi-one-dimensional ...

Yves Pointin

1985-01-01T23:59:59.000Z

155

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

Science Conference Proceedings (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

156

Optimizing the performance of streaming numerical kernels on the IBM Blue Gene/P PowerPC 450 processor  

Science Conference Proceedings (OSTI)

Several emerging petascale architectures use energy-efficient processors with vectorized computational units and in-order thread processing. On these architectures the sustained performance of streaming numerical kernels, ubiquitous in the solution of ... Keywords: Blue Gene/P, SIMD, code generation, high-performance computing, performance optimization

Tareq Malas, Aron J. Ahmadia, Jed Brown, John A. Gunnels, David E. Keyes

2013-05-01T23:59:59.000Z

157

The model of information retrieval based on the theory of hypercomplex numerical systems  

E-Print Network (OSTI)

The paper provided a description of a new model of information retrieval, which is an extension of vector-space model and is based on the principles of the theory of hypercomplex numerical systems. The model allows to some extent realize the idea of fuzzy search and allows you to apply in practice the model of information retrieval practical developments in the field of hypercomplex numerical systems.

Lande, D V; Boyarinova, Yu E

2012-01-01T23:59:59.000Z

158

Numerical Prediction of the Performance of Integrated Planar Solid-Oxide Fuel Cells, with Comparisons of Results from Several Codes  

DOE Green Energy (OSTI)

A numerical study of the thermal and electrochemical performance of a single-tube Integrated Planar Solid Oxide Fuel Cell (IP-SOFC) has been performed. Results obtained from two finite-volume computational fluid dynamics (CFD) codes FLUENT and SOHAB and from a two-dimensional inhouse developed finite-volume GENOA model are presented and compared. Each tool uses physical and geometric models of differing complexity and comparisons are made to assess their relative merits. Several single-tube simulations were run using each code over a range of operating conditions. The results include polarization curves, distributions of local current density, composition and temperature. Comparisons of these results are discussed, along with their relationship to the respective imbedded phenomenological models for activation losses, fluid flow and mass transport in porous media. In general, agreement between the codes was within 15% for overall parameters such as operating voltage and maximum temperature. The CFD results clearly show the effects of internal structure on the distributions of gas flows and related quantities within the electrochemical cells.

G. L. Hawkes; J. E. O'Brien; B. A. Haberman; A. J. Marquis; C. M. Baca; D. Tripepi; P. Costamagna

2008-06-01T23:59:59.000Z

159

PORFLOW Modeling Supporting The H-Tank Farm Performance Assessment  

Science Conference Proceedings (OSTI)

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

160

Numerical modelling of current transfer in nonlinear anisotropic conductive media  

E-Print Network (OSTI)

load vector and components of f jiM,M global damping matrix and components of M U nodal points of W Index of abbreviations HTS high temperature superconductor Bi-2212 Bi2Sr2CaCu2Ox Y-123 YBa2Cu3Ox EJ the electric field dependence upon the local current... experimental technique is presented. A mathematical analysis is also outlined that enables part of the magnetic field profile to be deduced directly from transport measurements. Chapter 4 discusses the principal approaches used in the numerical solution...

Baranowski, Robert Paul

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

Generic CSP Performance Model for NREL's System Advisor Model: Preprint  

SciTech Connect

The suite of concentrating solar power (CSP) modeling tools in NREL's System Advisor Model (SAM) includes technology performance models for parabolic troughs, power towers, and dish-Stirling systems. Each model provides the user with unique capabilities that are catered to typical design considerations seen in each technology. Since the scope of the various models is generally limited to common plant configurations, new CSP technologies, component geometries, and subsystem combinations can be difficult to model directly in the existing SAM technology models. To overcome the limitations imposed by representative CSP technology models, NREL has developed a 'Generic Solar System' (GSS) performance model for use in SAM. This paper discusses the formulation and performance considerations included in this model and verifies the model by comparing its results with more detailed models.

Wagner, M. J.; Zhu, G.

2011-08-01T23:59:59.000Z

162

A Hierarchy of Nonlinear Filtered Models—Numerical Solutions  

Science Conference Proceedings (OSTI)

Five filtered models, including two that are intermediate between the balanced and the primitive equations, are studied using actual weather data. The iterative method of solution works well in most cases. The two more general models are solved ...

Trond Iversen; Thor Erik Nordeng

1984-10-01T23:59:59.000Z

163

Numerical Experiments with a Stochastic Zonal Climate Model  

Science Conference Proceedings (OSTI)

A zonally averaged energy balance climate model is used to generate zonal temperature variability through fluctuating meridional energy transports. In the base model, stochastic transport fluctuations are introduced by multiplying the eddy ...

H. Nuzhet Dalfes; S. H. Schneider; Starley L. Thompson

1983-07-01T23:59:59.000Z

164

Numerical Modelling for Characterising the Flammability of Natural ...  

Science Conference Proceedings (OSTI)

... Modelling for Characterising the Flammability of Natural Fibre Reinforced Composites .... Influenced Corrosion of Pipeline Steels used in Oil & Gas Industry .

165

Numerical Modelling of Creep Deformation in a CMSX-4 Single ...  

Science Conference Proceedings (OSTI)

performance of a cooled turbine blade which is subject to a loading ... the following flow rule for the ?? is employed: ??L12 .... the gas turbine. The primary loads ...

166

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

167

Numerical modeling of geothermal systems with applications to Krafla, Iceland and Olkaria, Kenya  

SciTech Connect

The use of numerical models for the evaluation of the generating potential of high temperature geothermal fields has increased rapidly in recent years. In the present paper a unified numerical approach to the modeling of geothermal systems is discussed and the results of recent modeling of the Krafla geothermal field in Iceland and the Olkaria, Kenya, are described. Emphasis is placed on describing the methodology using examples from the two geothermal fields.

Bodvarsson, G.S.

1987-08-01T23:59:59.000Z

168

A Numerical Model for Combustion of Bubbling Thermoplastic ...  

Science Conference Proceedings (OSTI)

... [8] Wichman, IS, "A Model Describing the Steady-State Gasification of ... and Chemical Processes During Pyrolysis of a Large Biomass Particle," Fuel ...

2004-12-27T23:59:59.000Z

169

Numerical Model of a Tensioner System and Flex Joint  

E-Print Network (OSTI)

Top Tensioned Riser (TTR) and Steel Catenary Riser (SCR) are often used in a floating oil/gas production system deployed in deep water for oil transport. This study focuses on the improvements to the existing numerical code, known as CABLE3D, to allow for static and dynamic simulation of a TTR connected to a floating structure through a tensioner system or buoyancy can, and a SCR connected to a floating structure through a flex joint. A tensioner system usually consists of three to four cylindrical tensioners. Although the stiffness of individual tensioner is assumed to be linear, the resultant stiffness of a tensioner system may be nonlinear. The vertical friction at a riser guide is neglected assuming a roller is installed there. Near the water surface, a TTR is forced to move due to the motion of the upper deck of a floating structure as well as related riser guides. Using the up-dated CABLE3D, the dynamic simulation of TTRs will be made to reveal their motion, tension, and bending moment, which is important for the design. A flex joint is approximated by a rotational spring with linear stiffness, which is used as a connection between a SCR and a floating structure or a connection between a TTR and the sea floor. The improved CABLE3D will be integrated into a numerical code, known as COUPLE, for the simulation of the dynamic interaction among the hull of a floating structure, such as SPAR or TLP, its mooring system and riser system under the impact of wind, current and waves. To demonstrate the application of the improved CABLE3D and its integration with COUPLE, the related simulation is made for ‘Constitution’ SPAR under the met-ocean conditions of hurricane ‘Ike’. The mooring system of the Spar consists of nine mooring lines and the riser system consists of six TTRs and two SCRs.

Huang, Han

2013-08-01T23:59:59.000Z

170

Numerical Modeling of an Orographically Enhanced Precipitation Event Associated with Tropical Storm Rachel over Taiwan  

Science Conference Proceedings (OSTI)

An orographic rainfall event that occurred on 6–7 August 1999 during the passage of Tropical Storm (TS) Rachel over Taiwan is investigated by performing triply nested, nonhydrostatic numerical simulations using the Naval Research Laboratory's (...

Sen Chiao; Yuh-Lang Lin

2003-04-01T23:59:59.000Z

171

Landscape-Induced Atmospheric Flow and its Parameterization in Large-Scale Numerical Models  

Science Conference Proceedings (OSTI)

Extensive numerical simulations are performed to demonstrate that the landscape-induced mesoscale sensible heat, moisture, and momentum fluxes associated with spatially heterogeneous convective boundary layers can be larger than, and have a ...

Xubin Zeng; Roger A. Pielke

1995-05-01T23:59:59.000Z

172

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

173

Numerical simulation of a lattice polymer model at its integrable point  

E-Print Network (OSTI)

We revisit an integrable lattice model of polymer collapse using numerical simulations. This model was first studied by Bl\\"ote and Nienhuis in J. Phys. A. {\\bf 22}, 1415 (1989) and it describes polymers with some attraction, providing thus a model for the polymer collapse transition. At a particular set of Boltzmann weights the model is integrable and the exponents $\

A. Bedini; A. L. Owczarek; T. Prellberg

2012-11-01T23:59:59.000Z

174

Numerical Algorithms of the Lawrence--Doniach Model for Layered Superconductors and their Parallel Implementation  

Science Conference Proceedings (OSTI)

The Lawrence--Doniach model is often used for studying vortex dynamics in superconductors which exhibit a layered structure. In solving these model equations numerically, the added degrees of complexity due to the coupling and nonlinearity of the model ... Keywords: Lawrence--Doniach model, layered superconductors, parallel computing, parallel virtual machine, superconductivity

Qiang Du; Paul Gray

1999-05-01T23:59:59.000Z

175

Three-Dimensional Numerical Simulation of Plume Downwash with a k–? Turbulence Model  

Science Conference Proceedings (OSTI)

Plume downwash at a large oil-gathering facility in the Prudhoe Bay, Alaska oil-field reservation was simulated in a series of numerical experiments. The purpose of this study was to investigate the potential of the numerical model as a means of ...

Alex Guenther; Brian Lamb; David Stock

1990-07-01T23:59:59.000Z

176

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

177

A Numerical Model for the Equilibrium Shape of Electrified Raindrops  

Science Conference Proceedings (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

178

A Global Numerical Weather Prediction Model with Variable Resolution  

Science Conference Proceedings (OSTI)

A conformal transformation suggested by F. Schmidt is followed to implement a global spectral model with variable resolution. A conformal mapping is defined from a physical sphere (like the earth) to a transformed (computational) sphere. The ...

Vivek Hardiker

1997-01-01T23:59:59.000Z

179

Parameterization of Bulk Condensation in Numerical Cloud Models  

Science Conference Proceedings (OSTI)

The accuracy of the moist saturation adjustment scheme has been evaluated using a three-dimensional explicit microphysical cloud model. It was found that the error in saturation adjustment depends strongly on the CCN concentration in the ambient ...

Yefim L. Kogan; William J. Martin

1994-06-01T23:59:59.000Z

180

Ductile fracture modeling : theory, experimental investigation and numerical verification  

E-Print Network (OSTI)

The fracture initiation in ductile materials is governed by the damaging process along the plastic loading path. A new damage plasticity model for ductile fracture is proposed. Experimental results show that fracture ...

Xue, Liang, 1973-

2007-01-01T23:59:59.000Z

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.


181

Numerical modeling of hydrofracturing in a multilayer coal seam  

Science Conference Proceedings (OSTI)

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

182

Numerical heat transfer attic model using a radiant barrier system  

Science Conference Proceedings (OSTI)

A two-dimensional, steady-state finite-element model was developed to simulate the thermal effects of the application of an attic radiant barrier system (ARBS) inside a ventilated residential attic. The attic is ventilated using the exhaust air from an evaporative cooler. The study uses a {kappa}-{epsilon} turbulent model to describe the velocity and temperature distributions in the attic. The ambient temperature and solar isolation densities on the outside inclined attic surfaces are used as driving functions for the model. The model also included the appropriate heat exchange modes of convection and radiation on these outside surfaces. Several recirculation zones were visually observed in the attic flow pattern. Also, the use of the ARBS seems to lower the heat transfer through the ceiling by 25--30%, but this effect decreases significantly as the outside ventilation rates are increased through the attic space. The 2D model revealed some interesting temperature distributions along the attic surfaces that could not have been predicted by the one-dimensional models. The lower emissivity ARBS seems to raise the temperature of the inclined attic surfaces as well as the temperature of the exhausted ventilation air.

Moujaes, S.F.; Alsaiegh, N.T.

2000-04-01T23:59:59.000Z

183

Performance Evaluation of Dense Gas Dispersion Models  

Science Conference Proceedings (OSTI)

This paper summarizes the results of a study to evaluate the performance of seven dense gas dispersion models using data from three field experiments. Two models (DEGADIS and SLAB) are in the public domain and the other five (AIRTOX, CHARM, FOCUS,...

Jawad S. Touma; William M. Cox; Harold Thistle; James G. Zapert

1995-03-01T23:59:59.000Z

184

Evaluating the Performance of Land Surface Models  

Science Conference Proceedings (OSTI)

This paper presents a set of analytical tools to evaluate the performance of three land surface models (LSMs) that are used in global climate models (GCMs). Predictions of the fluxes of sensible heat, latent heat, and net CO2 exchange obtained ...

Gab Abramowitz; Ray Leuning; Martyn Clark; Andy Pitman

2008-11-01T23:59:59.000Z

185

Performing Bayesian inference with exemplar models  

E-Print Network (OSTI)

Probabilistic models have recently received much attention as accounts of human cognition. However, previous work has focused on formulating the abstract problems behind cognitive tasks and their probabilistic solutions, rather than considering mechanisms that could implement these solutions. Exemplar models are a successful class of psychological process models that use an inventory of stored examples to solve problems such as identification, categorization and function learning. We show that exemplar models can be interpreted as a sophisticated form of Monte Carlo approximation known as importance sampling, and thus provide a way to perform approximate Bayesian inference. Simulations of Bayesian inference in speech perception and concept learning show that exemplar models can account for human performance with only a few exemplars, for both simple and relatively complex prior distributions. Thus, we show that exemplar models provide a possible mechanism for implementing Bayesian inference.

Lei Shi; Naomi H. Feldman (naomi; Thomas L. Griffiths (tom

2008-01-01T23:59:59.000Z

186

Analytical Performance Models for Geologic Repositories  

SciTech Connect

This report presents analytical solutions of the dissolution and hydrogeologic transport of radionuclides in geologic repositories. Numerical examples are presented to demonstrate the equations resulting from these analyses. The subjects treated in the present report are: (a) Solubility-limited transport with transverse dispersion (Chapter 2); (b) Transport of a radionuclide chain with nonequilibrium chemical reactions (Chapter 3); (c) Advective transport in a two-dimensional flow field (Chapter 4); (d) Radionuclide.transport in fractured media (Chapter 5); (e) A mathematical model for EPA's analysis of generic repositories (Chapter 6); and (f) Dissolution of radionuclides from solid waste (Chapter 7).

Chambre, P.L.; Pigford, T.H.; Fujita, A.; Kanki, T.; Kobayashi,A.; Lung, H.; Ting, D.; Sato, Y.; Savoshy, S.J.

1982-10-01T23:59:59.000Z

187

Bayesian Estimation of Stochastic Parameterizations in a Numerical Weather Forecasting Model  

Science Conference Proceedings (OSTI)

Parameterizations in numerical models account for unresolved processes. These parameterizations are inherently difficult to construct and as such typically have notable imperfections. One approach to account for this uncertainty is through ...

Yong Song; Christopher K. Wikle; Christopher J. Anderson; Steven A. Lack

2007-12-01T23:59:59.000Z

188

A New Visibility Parameterization for Warm-Fog Applications in Numerical Weather Prediction Models  

Science Conference Proceedings (OSTI)

The objective of this work is to suggest a new warm-fog visibility parameterization scheme for numerical weather prediction (NWP) models. In situ observations collected during the Radiation and Aerosol Cloud Experiment, representing boundary ...

I. Gultepe; M. D. Müller; Z. Boybeyi

2006-11-01T23:59:59.000Z

189

Operational Assimilation of GPS Zenith Total Delay Observations into the Met Office Numerical Weather Prediction Models  

Science Conference Proceedings (OSTI)

Zenith total delay (ZTD) observations derived from ground-based GPS receivers have been assimilated operationally into the Met Office North Atlantic and European (NAE) numerical weather prediction (NWP) model since 2007. Assimilation trials were ...

Gemma V. Bennitt; Adrian Jupp

2012-08-01T23:59:59.000Z

190

Impulsively Started Flow in a Submarine Canyon: Comparison of Results from Laboratory and Numerical Models  

Science Conference Proceedings (OSTI)

Intercomparisons have been made of results from laboratory experiments and a numerical model for the flow in the vicinity of an idealized submarine canyon located along an otherwise continuous shelf. Motion in the rotating and continuously ...

Nicolas Pérenne; J. William Lavelle; David C. Smith IV; Don L. Boyer

2001-10-01T23:59:59.000Z

191

A Spectral Cumulus Parameterization for Use in Numerical Models of the Tropical Atmosphere  

Science Conference Proceedings (OSTI)

The spectral cumulus parameterization theory of Arakawa and Schubert is presented in the convective flux form as opposed to the original detrainment form. This flux form is more convenient for use in numerical prediction models. The equations are ...

James J. Hack; Wayne H. Schubert; Pedro L. Silva Dias

1984-04-01T23:59:59.000Z

192

Global Data on Land Surface Parameters from NOAA AVHRR for Use in Numerical Climate Models  

Science Conference Proceedings (OSTI)

This paper reviews satellite datasets from the NOAA Advanced Very High Resolution Radiometer that could be employed in support of numerical climate modeling at regional and global scales. Presently available NOAA operational and research datasets ...

G. Garik Gutman

1994-05-01T23:59:59.000Z

193

Use of Medium-Range Numerical Weather Prediction Model Output to Produce Forecasts of Streamflow  

Science Conference Proceedings (OSTI)

This paper examines an archive containing over 40 years of 8-day atmospheric forecasts over the contiguous United States from the NCEP reanalysis project to assess the possibilities for using medium-range numerical weather prediction model output ...

Martyn P. Clark; Lauren E. Hay

2004-02-01T23:59:59.000Z

194

An Eddy-Resolving Numerical Model of the Ventilated Thermocline: Time Dependence  

Science Conference Proceedings (OSTI)

A primitive equation, eddy-resolving numerical model is used to study the inherent time scales of variability in the subtropical ocean, assuming temporally constant surface forcing. Three primary scales arise: mesoscale variability of roughly 50-...

Michael D. Cox

1987-07-01T23:59:59.000Z

195

Estimates of Cn2 from Numerical Weather Prediction Model Output and Comparison with Thermosonde Data  

Science Conference Proceedings (OSTI)

Area-averaged estimates of Cn2 from high-resolution numerical weather prediction (NWP) model output are produced from local estimates of the spatial structure functions of refractive index with corrections for the inherent smoothing and filtering ...

Rod Frehlich; Robert Sharman; Francois Vandenberghe; Wei Yu; Yubao Liu; Jason Knievel; George Jumper

2010-08-01T23:59:59.000Z

196

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

Science Conference Proceedings (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

197

A Comprehensive Radiation Scheme for Numerical Weather Prediction Models with Potential Applications in Climate Simulations  

Science Conference Proceedings (OSTI)

A comprehensive scheme for the parameterization of radiative transfer in numerical weather Prediction (NWP) models has been developed. The scheme is based on the solution of the ?-two-stream version of the radiative transfer equation ...

Bodo Ritter; Jean-Francois Geleyn

1992-02-01T23:59:59.000Z

198

Data Mining Numerical Model Output for Single-Station Cloud-Ceiling Forecast Algorithms  

Science Conference Proceedings (OSTI)

Accurate cloud-ceiling-height forecasts derived from numerical weather prediction (NWP) model data are useful for aviation and other interests where low cloud ceilings have an impact on operations. A demonstration of the usefulness of data-mining ...

Richard L. Bankert; Michael Hadjimichael

2007-10-01T23:59:59.000Z

199

The Impact of Satellite Sounding Data on the Systematic Error of a Numerical Weather Prediction Model  

Science Conference Proceedings (OSTI)

The impact of satellite sounding data on the systematic errors of the numerical weather prediction model of the Israel Meteorological Service has been investigated. In general, satellite data have been shown to reduce systematic error, and in ...

Noah Wolfson; Albert Thomasell; Arnold Gruber; George Ohring

1985-06-01T23:59:59.000Z

200

Microscale Numerical Prediction over Montreal with the Canadian External Urban Modeling System  

Science Conference Proceedings (OSTI)

The Canadian urban and land surface external modeling system (known as urban GEM-SURF) has been developed to provide surface and near-surface meteorological variables to improve numerical weather prediction and to become a tool for environmental ...

Sylvie Leroyer; Stéphane Bélair; Jocelyn Mailhot; Ian B. Strachan

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.


201

An Upper Boundary Condition Permitting Internal Gravity Wave Radiation in Numerical Mesoscale Models  

Science Conference Proceedings (OSTI)

A radiative upper boundary condition is proposed for numerical mesoscale models which allows vertically propagating internal gravity waves to pass out of the computational domain with minimal reflection. In this formulation, the pressure along ...

Joseph B. Klemp; Dale R. Durran

1983-03-01T23:59:59.000Z

202

A Numerical Model of Internal Tides with Application to the Australian North West Shelf  

Science Conference Proceedings (OSTI)

A nonlinear, primitive equation, finite-difference numerical model is applied to the problem of the generation, propagation, and dissipation of internal tides over a cross section of the continental slope and shelf topography of a region on the ...

Peter E. Holloway

1996-01-01T23:59:59.000Z

203

The Effects of Subgrid Model Mixing and Numerical Filtering in Simulations of Mesoscale Cloud Systems  

Science Conference Proceedings (OSTI)

Using the newly developed Weather Research and Forecasting (WRF) model, this study investigates the effects of subgrid mixing and numerical filtering in mesoscale cloud simulations by examining the sensitivities to the parameters in turbulence-...

Tetsuya Takemi; Richard Rotunno

2003-09-01T23:59:59.000Z

204

A Numerical Modeling Study of Warm Offshore Flow over Cool Water  

Science Conference Proceedings (OSTI)

Numerical simulations of boundary layer evolution in offshore flow of warm air over cool water are conducted and compared with aircraft observations of mean and turbulent fields made at Duck, North Carolina. Two models are used: a two-dimensional,...

Eric D. Skyllingstad; Roger M. Samelson; Larry Mahrt; Phil Barbour

2005-02-01T23:59:59.000Z

205

Systematic Biases in the Microphysics and Thermodynamics of Numerical Models That Ignore Subgrid-Scale Variability  

Science Conference Proceedings (OSTI)

A grid box in a numerical model that ignores subgrid variability has biases in certain microphysical and thermodynamic quantities relative to the values that would be obtained if subgrid-scale variability were taken into account. The biases are ...

Vincent E. Larson; Robert Wood; Paul R. Field; Jean-Christophe Golaz; Thomas H. Vonder Haar; William R. Cotton

2001-05-01T23:59:59.000Z

206

The Sensitivity of Numerically Simulated Cyclic Mesocyclogenesis to Variations in Model Physical and Computational Parameters  

Science Conference Proceedings (OSTI)

In a previous paper, a three-dimensional numerical model was used to study the evolution of successive mesocyclones produced by a single supercell storm, that is, cyclic mesocyclogenesis. Not all supercells, simulated or observed, exhibit this ...

Edwin J. Adlerman; Kelvin K. Droegemeier

2002-11-01T23:59:59.000Z

207

A New Diffusion Scheme for Numerical Models Based on Full Irreversibility  

Science Conference Proceedings (OSTI)

In this work, the forecast accuracy of a numerical weather prediction model is improved by emulating physical dissipation as suggested by the second law of thermodynamics, which controls the irreversible evolutionary direction of a many-body ...

C. Liu; Y. Liu; H. Xu

2009-04-01T23:59:59.000Z

208

Estimation of Meteorological Parameters for Air Quality Management: Coupling of Sodar Data with Simple Numerical Models  

Science Conference Proceedings (OSTI)

In this paper an attempt is made to couple sodar data and simple numerical models to calculate the wind field and the boundary layer parameters that are relevant to air quality monitoring and studies. For this purpose, a diagnostic, mass-...

Dimitrios Melas; Giulia Abbate; Dias Haralampopoulos; Alexandros Kelesidis

2000-04-01T23:59:59.000Z

209

Subjective Verification of Numerical Models as a Component of a Broader Interaction between Research and Operations  

Science Conference Proceedings (OSTI)

Systematic subjective verification of precipitation forecasts from two numerical models is presented and discussed. The subjective verification effort was carried out as part of the 2001 Spring Program, a seven-week collaborative experiment ...

John S. Kain; Michael E. Baldwin; Paul R. Janish; Steven J. Weiss; Michael P. Kay; Gregory W. Carbin

2003-10-01T23:59:59.000Z

210

Human equivalent antenna model for HF exposures: analytical versus numerical approach  

Science Conference Proceedings (OSTI)

In this paper, the human exposure to HF radiation is analyzed using the simplified human equivalent antenna model featuring analytical and numerical approach, respectively. Namely, the human body is represented by an equivalent receiving straight thin ...

Dragan Poljak; Silvestar Sesnic; Ivana Zulim

2009-09-01T23:59:59.000Z

211

Generation and Propagation of 30-Day Waves in a Numerical Model of the Pacific  

Science Conference Proceedings (OSTI)

A multilevel numerical model is applied to the equatorial Pacific Ocean, driven by long-term averaged, monthly varying winds. In agreement with satellite-observed sea surface temperatures, the solution is unstable at certain times of year and ...

Michael D. Cox

1980-08-01T23:59:59.000Z

212

Parameterization and Impact of Ice initiation Processes Relevant to Numerical Model Simulations of Cirrus Clouds  

Science Conference Proceedings (OSTI)

An effort to improve descriptions of ice initiation processes of relevance to cirrus clouds for use in regional-scale numerical cloud models with bulk microphysical schemes is described. This is approached by deriving practical parameterizations ...

Paul J. DeMott; Michael P. Meyers; William R. Cotton

1994-01-01T23:59:59.000Z

213

Laboratory–Numerical Model Comparisons of Canyon Flows: A Parameter Study  

Science Conference Proceedings (OSTI)

An integrated set of laboratory and numerical-model experiments has been conducted to understand the development of residual circulation surrounding a coastal canyon and to explore further the degree to which laboratory experiments can provide ...

Don L. Boyer; Dale B. Haidvogel; Nicolas Pérenne

2004-07-01T23:59:59.000Z

214

Modeling well performance in compartmentalized gas reservoirs  

E-Print Network (OSTI)

Predicting the performance of wells in compartmentalized reservoirs can be quite challenging to most conventional reservoir engineering tools. The purpose of this research is to develop a Compartmentalized Gas Depletion Model that applies not only to conventional consolidated reservoirs (with constant formation compressibility) but also to unconsolidated reservoirs (with variable formation compressibility) by including geomechanics, permeability deterioration and compartmentalization to estimate the OGIP and performance characteristics of each compartment in such reservoirs given production data. A geomechanics model was developed using available correlation in the industry to estimate variable pore volume compressibility, reservoir compaction and permeability reduction. The geomechanics calculations were combined with gas material balance equation and pseudo-steady state equation and the model was used to predict well performance. Simulated production data from a conventional gas Simulator was used for consolidated reservoir cases while synthetic data (generated by the model using known parameters) was used for unconsolidated reservoir cases. In both cases, the Compartmentalized Depletion Model was used to analyze data, and estimate the OGIP and Jg of each compartment in a compartmentalized gas reservoir and predict the subsequent reservoir performance. The analysis was done by history-matching gas rate with the model using an optimization technique. The model gave satisfactory results with both consolidated and unconsolidated reservoirs for single and multiple reservoir layers. It was demonstrated that for unconsolidated reservoirs, reduction in permeability and reservoir compaction could be very significant especially for unconsolidated gas reservoirs with large pay thickness and large depletion pressure.

Yusuf, Nurudeen

2007-12-01T23:59:59.000Z

215

Numerical modeling of hydrogen-fueled internal combustion engines  

DOE Green Energy (OSTI)

The planned use of hydrogen as the energy carrier of the future introduces new challenges and opportunities, especially to the engine design community. Hydrogen is a bio-friendly fuel that can be produced from renewable resources and has no carbon dioxide combustion products; and in a properly designed ICE, almost zero NO{sub x} and hydrocarbon emissions can be achieved. Because of the unique properties of hydrogen combustion - in particular the highly wrinkled nature of the laminar flame front due to the preferential diffusion instability - modeling approaches for hydrocarbon gaseous fuels are not generally applicable to hydrogen combustion. This paper reports on the current progress to develop a engine design capability based on KIVA family of codes for hydrogen-fueled, spark-ignited engines in support of the National Hydrogen Program. A turbulent combustion model, based on a modified eddy-turnover model in conjunction with an intake flow valve model, is found to describe well the efficiency and NO{sub x} emissions of this engine satisfy the Equivalent Zero Emission Vehicle (EZEV) standard established by the California Resource Board. 26 refs., 10 figs., 1 tab.

Johnson, N.L.; Amsden, A.A.

1996-12-31T23:59:59.000Z

216

Room ventilation and its influence on the performance of fume cupboards: A parametric numerical study  

Science Conference Proceedings (OSTI)

The three-dimensional turbulent flow in a typical chemical laboratory containing two fume cupboards and furniture is investigated numerically in order to obtain detailed information needed for the improved design of ventilating systems for such rooms. The flow inside the two fume cupboards is simulated simultaneously with the room flow, and its dependence on the flow structure in the room is shown. The flow inside the cupboards and in the vicinity of their sash openings has been found to be essentially three-dimensional. Several room parameters are varied, and a quantitative evaluation of their influence on the flow, the comfort characteristics, and the ventilation efficiency is given. Additional ceiling-mounted openings, which extract room air outside the fume cupboards, can affect the capture efficiency of the cupboards, as well as the quality of the air in the room. It has been found also that small changes in the position of the radial inlet ceiling-mounted diffuser can influence the air quality of the room and at the same time the draught risk. These effects are shown for a given room arrangement. To accommodate the complex geometry, the elliptical nature of the mathematical problem, and the use of a turbulence model, a multigrid acceleration method with 245,000 control volumes is used, allowing CPU times on a workstation to become acceptable.

Denev, J.A.; Durst, F.; Mohr, B. [Friedrich Alexander Univ. Erlangen-Nuernberg, Erlangen (Germany)] [Friedrich Alexander Univ. Erlangen-Nuernberg, Erlangen (Germany)

1997-02-01T23:59:59.000Z

217

Numerical modeling of interaction of a current with a circular cylinder near a rigid bed  

Science Conference Proceedings (OSTI)

The numerical modeling of 2D turbulent flow around a smooth horizontal circular cylinder near a rigid bed with gap ratio G/D=0.3 at Reynolds number Re"D=9500 is investigated. Ansys^(R) 10.0-FLOTRAN program package is used to solve the governing equations ... Keywords: Circular cylinder, Numerical model, Particle image velocimetry, Steady flow, Strouhal number, Velocity field

M. Salih Kirkgoz; A. Alper Oner; M. Sami Akoz

2009-11-01T23:59:59.000Z

218

Studying performance of DEVS modeling and simulation environments using the DEVStone benchmark  

Science Conference Proceedings (OSTI)

The Discrete Event System Specification (DEVS) formal modeling and simulation (M&S) framework (which supports hierarchical and modular model composition) has been widely used to understand, analyze and develop a variety of systems. Numerous DEVS simulators ... Keywords: DEVS, modeling and simulation tools, simulator performance evaluation, synthetic benchmarks

Gabriel Wainer; Ezequiel Glinsky; Marcelo Gutierrez-Alcaraz

2011-07-01T23:59:59.000Z

219

Critical review of glass performance modeling  

Science Conference Proceedings (OSTI)

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

220

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

Recanati, Catherine

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

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

Science Conference Proceedings (OSTI)

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

222

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

Science Conference Proceedings (OSTI)

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

223

Numerical Models of Broad-Bandwidth Nanosecond Optical Parametric Oscillators  

SciTech Connect

We present three new methods for modeling broad-bandwidth, nanosecond optitcal parametric oscillators in the plane-wave approximation. Each accounts for the group-velocity differences that determine the operating linewidth of unseeded optical parametric oscillators, and each allows the signal and idler waves to develop from quantum noise. The first two methods are based on split-step integration methods in which nonlinear mixing and propagation are calculated separately on alternate steps. One method relies on Fourier transforming handle propagation, wiih mixing integrated over a the fields between t and u to Az step: the other transforms between z and k= in the propagation step, with mixing integrated over At. The third method is based on expansion of the three optical fields in terms of their respective longitudinal empty cavity modes, taking into account the cavity boundary condi- tions. Equations describing the time development of the mode amplitudes are solved to yield the time dependence of the three output fields. These plane-wave models exclude diffractive effects, but can be readily extended to include them.

Bowers, M.S.; Gehr. R.J.; Smith, A.V.

1998-10-22T23:59:59.000Z

224

PV performance modeling workshop summary report.  

DOE Green Energy (OSTI)

During the development of a solar photovoltaic (PV) energy project, predicting expected energy production from a system is a key part of understanding system value. System energy production is a function of the system design and location, the mounting configuration, the power conversion system, and the module technology, as well as the solar resource. Even if all other variables are held constant, annual energy yield (kWh/kWp) will vary among module technologies because of differences in response to low-light levels and temperature. A number of PV system performance models have been developed and are in use, but little has been published on validation of these models or the accuracy and uncertainty of their output. With support from the U.S. Department of Energy's Solar Energy Technologies Program, Sandia National Laboratories organized a PV Performance Modeling Workshop in Albuquerque, New Mexico, September 22-23, 2010. The workshop was intended to address the current state of PV system models, develop a path forward for establishing best practices on PV system performance modeling, and set the stage for standardization of testing and validation procedures for models and input parameters. This report summarizes discussions and presentations from the workshop, as well as examines opportunities for collaborative efforts to develop objective comparisons between models and across sites and applications.

Stein, Joshua S.; Tasca, Coryne Adelle (SRA International, Inc., Fairfax, VA); Cameron, Christopher P.

2011-05-01T23:59:59.000Z

225

Numerical modeling of water injection into vapor-dominatedgeothermal reservoirs  

SciTech Connect

Water injection has been recognized as a powerful techniquefor enhancing energy recovery from vapor-dominated geothermal systemssuch as The Geysers. In addition to increasing reservoir pressures,production well flow rates, and long-term sustainability of steamproduction, injection has also been shown to reduce concentrations ofnon-condensible gases (NCGs) in produced steam. The latter effectimproves energy conversion efficiency and reduces corrosion problems inwellbores and surface lines.This report reviews thermodynamic andhydrogeologic conditions and mechanisms that play an important role inreservoir response to water injection. An existing general-purposereservoir simulator has been enhanced to allow modeling of injectioneffects in heterogeneous fractured reservoirs in three dimensions,including effects of non-condensible gases of different solubility.Illustrative applications demonstrate fluid flow and heat transfermechanisms that are considered crucial for developing approaches to insitu abatement of NCGs.

Pruess, Karsten

2006-11-06T23:59:59.000Z

226

A numerical analysis of condenser performance of a seawater desalination system  

E-Print Network (OSTI)

This thesis presents the numerical analysis of three type condensers for desalination of seawater system. The condensers that were analyzed were a finned tube condenser that was built in Malaysia desalination plant, a ...

Mohamed, Hassan, S.B. Massachusetts Institute of Technology

2009-01-01T23:59:59.000Z

227

Analytical and numerical models of uranium ignition assisted by hydride formation  

DOE Green Energy (OSTI)

Analytical and numerical models of uranium ignition assisted by the oxidation of uranium hydride are described. The models were developed to demonstrate that ignition of large uranium ingots could not occur as a result of possible hydride formation during storage. The thermodynamics-based analytical model predicted an overall 17 C temperature rise of the ingot due to hydride oxidation upon opening of the storage can in air. The numerical model predicted locally higher temperature increases at the surface; the transient temperature increase quickly dissipated. The numerical model was further used to determine conditions for which hydride oxidation does lead to ignition of uranium metal. Room temperature ignition only occurs for high hydride fractions in the nominally oxide reaction product and high specific surface areas of the uranium metal.

Totemeier, T.C.; Hayes, S.L. [Argonne National Lab., Idaho Falls, ID (United States). Engineering Div.

1996-05-01T23:59:59.000Z

228

Horizontal Heat Fluxes over Complex Terrain Computed Using a Simple Mixed-Layer Model and a Numerical Model  

Science Conference Proceedings (OSTI)

The thermally induced local circulation over a periodic valley is simulated by a two-dimensional numerical model that does not include condensational processes. During the daytime of a clear, calm day, heat is transported from the mountainous ...

Fujio Kimura; Tuneo Kuwagata

1995-02-01T23:59:59.000Z

229

A Quasi-Geostrophic Circulation Model of the Northeast Pacific. Part I: A Preliminary Numerical Experiment  

Science Conference Proceedings (OSTI)

A limited-area quasi-geostrophic numerical model with mesoscale resolution is developed to study the circulation in the northeast (NE) Pacific Ocean. The model domain extends from the British Columbia-Alaska coast out to 170°W and down to 45°N, ...

Patrick F. Cummins; Lawrence A. Mysak

1988-09-01T23:59:59.000Z

230

Numerical Simulation of Polar Lows and Comma Clouds Using Simple Dry Models  

Science Conference Proceedings (OSTI)

Linear and nonlinear numerical channel models are used to simulate polar low/comma cloud evolution. The purpose of this study is to see how much realism can be obtained using models that do not include water vapor. The study was inspired by ...

Stephen E. Mudrick

1987-12-01T23:59:59.000Z

231

Numerical Model-Reality Intercomparison Tests Using Small-Sample Statistics  

Science Conference Proceedings (OSTI)

When a numerical model's representation of a physical field is to be compared with a corresponding real observed field, it is usually the case that the numbers of realizations of model and observed field are relatively small, so that the natural ...

Rudolph W. Preisendorfer; Tim P. Barnett

1983-08-01T23:59:59.000Z

232

A numerical method for solving convection-reaction-diffusion multivalued equations in fire spread modelling  

Science Conference Proceedings (OSTI)

A numerical method is developed for fire spread simulation modelling. The two-dimensional surface model presented takes into account moisture content, radiation, wind and slope effects, which are by far the most important mechanisms in fire spread. We ... Keywords: 02.60.Cb, 02.60.Lj, 02.70.Dh, Fire, Moisture, Pyrolysis, Radiation, Slope, Wind

L. Ferragut; M. I. Asensio; S. Monedero

2007-06-01T23:59:59.000Z

233

Evaluation of a Simple Numerical Model as a Mesoscale Weather Forecasting Tool  

Science Conference Proceedings (OSTI)

During the America's Cup race series of 1986–1987, a numerical sea breeze model was used to assist offshore forecasts. The exercise has provided a detailed insight into the extent to which such a model may assist the forecasting process the ...

P. J. Rye

1989-12-01T23:59:59.000Z

234

Numerical Modeling of Fractured Shale-Gas and Tight-Gas Reservoirs Using Unstructured Grids  

E-Print Network (OSTI)

Various models featuring horizontal wells with multiple induced fractures have been proposed to characterize flow behavior over time in tight gas and shale gas systems. Currently, there is little consensus regarding the effects of non-ideal fracture geometries and coupled primary-secondary fracture interactions on reservoir performance in these unconventional gas reservoirs. This thesis provides a grid construction tool to generate high-resolution unstructured meshes using Voronoi grids, which provides the flexibility required to accurately represent complex geologic domains and fractures in three dimensions. Using these Voronoi grids, the interaction between propped hydraulic fractures and secondary "stress-release" fractures were evaluated. Additionally, various primary fracture configurations were examined, where the fractures may be non-planar or non-orthogonal. For this study, a numerical model was developed to assess the potential performance of tight gas and shale gas reservoirs. These simulations utilized up to a half-million grid-blocks and consider a period of up to 3,000 years in some cases. The aim is to provide very high-definition reference numerical solutions that will exhibit virtually all flow regimes we can expect in these unconventional gas reservoirs. The simulation results are analyzed to identify production signatures and flow regimes using diagnostic plots, and these interpretations are confirmed using pressure maps where useful. The coupled primary-secondary fracture systems with the largest fracture surface areas are shown to give the highest production in the traditional "linear flow" regime (which occurs for very high conductivity vertical fracture cases). The non-ideal hydraulic fracture geometries are shown to yield progressively lower production as the angularity of these fractures increases. Hence, to design optimum fracture completions, we should endeavor to keep the fractures as orthogonal to the horizontal well as possible. This work expands the current understanding of flow behavior in fractured tight-gas and shale-gas systems and may be used to optimize fracture and completion design, to validate analytical models and to facilitate more accurate reserves estimation.

Olorode, Olufemi Morounfopefoluwa

2011-12-01T23:59:59.000Z

235

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

E-Print Network (OSTI)

Non-linear finite element models were developed to simulate transient heat and mass transfer in the soil surrounding the ground heat exchangers of ground-coupled heat pumps (GCHPs) operating in the cooling mode. Parametric studies were performed with two dimensional horizontal cross sectional models. The heat transfer and temperature distributions yielded excess errors less than 6% and 3%, respectively, when compared to analytical solutions. Two constant temperature sources performed equivalent heating as one constant temperature source having twice the radius. For constant heat flux sources, the equivalent radius was found to be increased by ?2. A heat flux equivalent radius (tau_h,eqv) was developed and shown to be more consistent than the geometric radius (tau_g,eqv). All equivalent radii varied with time and source separation. A heat exchanger effectiveness for two sources, (epsilon_A), was introduced based on an earlier definition for one source. Effectiveness was found to be independent of a dimensionless temperature variable that included temperatures of the tubes and soil, and varied only with separation distance at steady state. Thermal short circuiting was defined as 1 – epsilon_A and ranged from 38% to 47% in the reasonable 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 less than 2 W/m-K. The overall heat transfer increased with backfill thermal conductivity but epsilon_A decreased. Therefore, the backfill effectiveness of Couvillion was used to rank backfill performance. The range of the backfill effectiveness was from 45% for touching bentonite backfill tubes to 60% for the fictitious backfill at a separation of seven l/Do. Moisture migration was incorporated into the numerical finite element model by formulating coupled partial differential equations for non-linear heat and mass transfer. Simulations with decreasing soil moisture contents resulted in lower thermal conductivity and performance degradation. Increasing the bore hole size improved the efficiency (decreased thermal short circuiting) by as much as 20%. In addition, higher conductivity fictitious backfills improved efficiency by up to an additional 20%. However, cost savings in both cases had a negligible effect compared to the bore hole cost.

Muraya, Norman K.

1994-12-01T23:59:59.000Z

236

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

237

DRIFT : a numerical simulation solution for cooling tower drift eliminator performance  

E-Print Network (OSTI)

A method for the analysis of the performance of standard industrial evaporative cooling tower drift

Chan, Joseph Kwok-Kwong

238

Cluster cross sections for strong lensing: analytic and numerical lens models  

E-Print Network (OSTI)

The statistics of gravitationally lensed arcs was recognised earlier as a potentially powerful cosmological probe. However, while fully numerical models find orders of magnitude difference between the arc probabilities in different cosmological models, analytic models tend to find markedly different results. We introduce in this paper an analytic cluster lens model which improves upon existing analytic models in four ways. (1) We use the more realistic Navarro-Frenk-White profile instead of singular isothermal spheres, (2) we include the effect of cosmology on the compactness of the lenses, (3) we use elliptical instead of axially symmetric lenses, and (4) we take the intrinsic ellipticity of sources into account. While these improvements to the analytic model lead to a pronounced increase of the arc probability, comparisons with numerical models of the same virial mass demonstrate that the analytic models still fall short by a substantial margin of reproducing the results obtained with numerical models. Using multipole expansions of cluster mass distributions, we show that the remaining discrepancy can be attributed to substructure inside clusters and tidal fields contributed by the cluster surroundings, effects that cannot reasonably and reliably be mimicked in analytic models.

Massimo Meneghetti; Matthias Bartelmann; Lauro Moscardini

2002-01-30T23:59:59.000Z

239

Development of a numerical computer code and circuit element models for simulation of firing systems  

SciTech Connect

Numerical simulation of firing systems requires both the appropriate circuit analysis framework and the special element models required by the application. We have modified the SPICE circuit analysis code (version 2G.6), developed originally at the Electronic Research Laboratory of the University of California, Berkeley, to allow it to be used on MSDOS-based, personal computers and to give it two additional circuit elements needed by firing systems--fuses and saturating inductances. An interactive editor and a batch driver have been written to ease the use of the SPICE program by system designers, and the interactive graphical post processor, NUTMEG, supplied by U. C. Berkeley with SPICE version 3B1, has been interfaced to the output from the modified SPICE. Documentation and installation aids have been provided to make the total software system accessible to PC users. Sample problems show that the resulting code is in agreement with the FIRESET code on which the fuse model was based (with some modifications to the dynamics of scaling fuse parameters). In order to allow for more complex simulations of firing systems, studies have been made of additional special circuit elements--switches and ferrite cored inductances. A simple switch model has been investigated which promises to give at least a first approximation to the physical effects of a non ideal switch, and which can be added to the existing SPICE circuits without changing the SPICE code itself. The effect of fast rise time pulses on ferrites has been studied experimentally in order to provide a base for future modeling and incorporation of the dynamic effects of changes in core magnetization into the SPICE code. This report contains detailed accounts of the work on these topics performed during the period it covers, and has appendices listing all source code written documentation produced.

Carpenter, K.H. (Kansas State Univ., Manhattan, KS (USA). Dept. of Electrical and Computer Engineering)

1990-07-02T23:59:59.000Z

240

Modeling and Simulation of HVAC Faulty Operations and Performance...  

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

Modeling and Simulation of HVAC Faulty Operations and Performance Degradation due to Maintenance Issues Title Modeling and Simulation of HVAC Faulty Operations and 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.


241

Modeling the Performance of Lithium-Ion Batteries and Capacitors...  

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

Modeling the Performance of Lithium-Ion Batteries and Capacitors during Hybird Electric-Vehicle Operation Title Modeling the Performance of Lithium-Ion Batteries and Capacitors...

242

Smart Grid Cybersecurity: Job Performance Model Report and Phase...  

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

Smart Grid Cybersecurity: Job Performance Model Report and Phase 1 Overview (August 2012) Smart Grid Cybersecurity: Job Performance Model Report and Phase 1 Overview (August 2012)...

243

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

244

An accurate performance model of fully adaptive routing in wormhole-switched two-dimensional mesh multicomputers  

Science Conference Proceedings (OSTI)

Numerous analytical performance models have been proposed for deterministic wormhole-routed mesh networks while only a single model, to our best knowledge, has been suggested for fully adaptive wormhole routing in mesh interconnection networks. This ... Keywords: Adaptive wormhole routing, Analytical modeling, Interconnection network, Meshes, Multicomputer, Performance evaluation

H. Hashemi-Najafabadi; H. Sarbazi-Azad; P. Rajabzadeh

2007-11-01T23:59:59.000Z

245

Numerical Classical and Quantum Mechanical simulations of Charge Density wave models  

E-Print Network (OSTI)

We first present how to do a computer simulation of Charge Density Waves using a driven harmonic oscillator model by a numerical scheme as initially formulated by Littlewood, and then afterwards use this to present how the dielectric model as presented by this proceedure leads to a blow up at the initialization of a threshold field ET. We find that this is highly unphysical and this initiated our inquiry as to alternative models. Afterwards, we then investigate hwo to present this transport problem of CDW quantum mechanically, threough a numerical simulation of the massive Schwinger model. We find that this single chaing quantum mechanical simulation uwed to formulate solutions to CDW transport in itself is insufficient for transport of solitons(anti-solitons) through a pinning gap model of CDW. We show that a model Hamiltonian with Peierls condensation energy used to couple adjacent chains (or transverse wave vectors) permits formation of solitons (anti- solitons) which can be used to transport CDW through a potential barrier. This addition of the Peierls condensation energy term is essential for any quantum model of Charge Density Waves to give tunneling behavior as seen via a numerical simulation.

A. W. Beckwith

2004-09-13T23:59:59.000Z

246

Fluid Temperature and Power Estimation of Geothermal Power Plants by a Simplified Numerical Model  

Science Conference Proceedings (OSTI)

This paper presents an estimation of power generated in a given geothermal heat pipe system. Such power generation is basically controlled by the ultimate temperature of fluid flowing through the u-shape pipes and could also be affected by power consumption ... Keywords: energy, geothermal power plant, numerical model, heat conduction, optimum design

Ge Ou; Itai Einav

2010-08-01T23:59:59.000Z

247

Local Mass Conservation and Velocity Splitting in PV-Based Balanced Models. Part II: Numerical Results  

Science Conference Proceedings (OSTI)

The effects of enforcing local mass conservation on the accuracy of non-Hamiltonian potential-vorticity- based balanced models (PBMs) are examined numerically for a set of chaotic shallow-water f-plane vortical flows in a doubly periodic square ...

Ali R. Mohebalhojeh; Michael E. McIntyre

2007-06-01T23:59:59.000Z

248

Numerical Modeling of a Line of Towering Cumulus on Day 226 of GATE  

Science Conference Proceedings (OSTI)

A three-dimensional numerical model with warm rain bulk cloud physics is used to investigate the shallow convection observed on day 226 of GATE. This convection had cloud tops at 3.0 km, cloud bases at 0.4 km and approximately 0.1 cm of rain at ...

Frank B. Lipps; Richard S. Hemler

1988-09-01T23:59:59.000Z

249

The Parameterization of Radiation for Numerical Weather Prediction and Climate Models  

Science Conference Proceedings (OSTI)

This paper presents a review of the various methods used to compute both the fluxes and the rate of heating and/or cooling due to atmospheric radiation for use in numerical models of atmospheric circulation. The paper does not follow, step by ...

Graeme L. Stephens

1984-04-01T23:59:59.000Z

250

A Numerical Model of the Formation and Evolution of a Low-Level Jet  

Science Conference Proceedings (OSTI)

A one-layer. one-dimensional numerical model is described which simulates the life cycle of the extratropical low-level jet (LLJ). The LLJ starts as an isallobaric wind near the point of maximum pressure tall. Subsequently, the LLJ expands over a ...

Dušan Djuri?

1981-02-01T23:59:59.000Z

251

A Note on the Sea Surface Temperature Sensitivity of a Numerical Model of Tropical Storm Genesis  

Science Conference Proceedings (OSTI)

In a three-dimensional numerical model of a tropical disturbance, a spectrum of development stages, from a weakening wave to a mature tropical storm, was obtained with a 5 K range (298 to 303 K) sea surface temperature (SST). However, the ...

Robert E. Tuleya; Yoshio Kurihara

1982-12-01T23:59:59.000Z

252

Shallow water numerical model of the wave generated by the Vajont landslide  

Science Conference Proceedings (OSTI)

On October 9th 1963 a huge landslide fell into the Vajont artificial reservoir in Northern Italy, and displaced the water which overtopped the dam and produced a destructive wave that inundated the valley causing about 2000 casualties and complete devastation. ... Keywords: Finite volume scheme, Moving boundary condition, Numerical model, Shallow water equations, Vajont landslide

Silvia Bosa; Marco Petti

2011-04-01T23:59:59.000Z

253

Sea-Breeze Interactions along a Concave Coastline in Southern Australia: Observations and Numerical Modeling Study  

Science Conference Proceedings (OSTI)

Observations and numerical modeling of the bay and ocean breezes of Port Phillip Bay show that the interaction of these two breezes produces features undocumented in previous sea-breeze studies. The first of these is the formation of a mesoscale ...

Deborah J. Abbs

1986-05-01T23:59:59.000Z

254

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

Science Conference Proceedings (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

255

Numerical simulation of sloshing in LNG tanks with a compressible two-phase model  

E-Print Network (OSTI)

The study of liquid dynamics in LNG tanks is getting more and more important with the actual trend of LNG tankers sailing with partially filled tanks. The effect of sloshing liquid in the tanks on pressure levels at the tank walls and on the overall ship motion indicates the relevance of an accurate simulation of the fluid behaviour. This paper presents the simulation of sloshing LNG by a compressible two-phase model and the validation of the numerical model on model-scale sloshing experiments. The details of the numerical model, an improved Volume Of Fluid (iVOF) method, are presented in the paper. The program has been developed initially to study the sloshing of liquid fuel in spacecraft. The micro-gravity environment requires a very accurate and robust description of the free surface. Later, the numerical model has been used for calculations for different offshore applications, including green water loading. The model has been extended to take two-phase flow effects into account. These effects are particularly important for sloshing in tanks. The complex mixture of the liquid and gas phase around

Rik Wemmenhove; Arthur E. P. Veldman; Tim Bunnik

2007-01-01T23:59:59.000Z

256

Performance model assessment for multi-junction concentrating photovoltaic systems.  

DOE Green Energy (OSTI)

Four approaches to modeling multi-junction concentrating photovoltaic system performance are assessed by comparing modeled performance to measured performance. Measured weather, irradiance, and system performance data were collected on two systems over a one month period. Residual analysis is used to assess the models and to identify opportunities for model improvement.

Riley, Daniel M.; McConnell, Robert. (Amonix, Inc., Seal Beach, CA); Sahm, Aaron (University of Nevada, Las Vegas, NV); Crawford, Clark (Amonix, Inc., Seal Beach, CA); King, David L.; Cameron, Christopher P.; Foresi, James S. (Emcore, Inc., Albuquerque, NM)

2010-03-01T23:59:59.000Z

257

Numerical prediction of aerodynamic characteristics of prismatic cylinder by finite element method with Spalart-Allmaras turbulence model  

Science Conference Proceedings (OSTI)

Aerodynamic characteristic of prismatic cylinders is numerically investigated by using finite element method with Spalart-Allmaras turbulence model. The developed model is verified against the available experimental and numerical results for turbulent ... Keywords: Aerodynamic characteristic, Afterbody shape, Finite element method, Prismatic cylinder, Turbulent flow, Unsteady S-A model

Yan Bao; Dai Zhou; Cheng Huang; Qier Wu; Xiang-qiao Chen

2011-02-01T23:59:59.000Z

258

Aspen: a domain specific language for performance modeling  

Science Conference Proceedings (OSTI)

We present a new approach to analytical performance modeling using Aspen, a domain specific langauge. Aspen (Abstract Scalable Performance Engineering Notation) fills an important gap in existing performance modeling techniques and is designed to enable ...

Kyle L. Spafford; Jeffrey S. Vetter

2012-11-01T23:59:59.000Z

259

Numerical Modeling Study and Assessment of PWR Fuel Rod and Assembly Distortion  

Science Conference Proceedings (OSTI)

Fuel assembly and rod distortion experienced in pressurized water reactors (PWRs) result in numerous operational challenges to plant operators such as mechanical interference between distorted assembly and control rods, difficulties in unloading and reloading cores during outages, and possibly anomalous fuel performance due to atypical water gaps. Therefore, an improved understanding of the various parameters contributing to distortion is important in order to manage or otherwise eliminate these ...

2012-11-30T23:59:59.000Z

260

VINE-A NUMERICAL CODE FOR SIMULATING ASTROPHYSICAL SYSTEMS USING PARTICLES. II. IMPLEMENTATION AND PERFORMANCE CHARACTERISTICS  

Science Conference Proceedings (OSTI)

We continue our presentation of VINE. In this paper, we begin with a description of relevant architectural properties of the serial and shared memory parallel computers on which VINE is intended to run, and describe their influences on the design of the code itself. We continue with a detailed description of a number of optimizations made to the layout of the particle data in memory and to our implementation of a binary tree used to access that data for use in gravitational force calculations and searches for smoothed particle hydrodynamics (SPH) neighbor particles. We describe the modifications to the code necessary to obtain forces efficiently from special purpose 'GRAPE' hardware, the interfaces required to allow transparent substitution of those forces in the code instead of those obtained from the tree, and the modifications necessary to use both tree and GRAPE together as a fused GRAPE/tree combination. We conclude with an extensive series of performance tests, which demonstrate that the code can be run efficiently and without modification in serial on small workstations or in parallel using the OpenMP compiler directives on large-scale, shared memory parallel machines. We analyze the effects of the code optimizations and estimate that they improve its overall performance by more than an order of magnitude over that obtained by many other tree codes. Scaled parallel performance of the gravity and SPH calculations, together the most costly components of most simulations, is nearly linear up to at least 120 processors on moderate sized test problems using the Origin 3000 architecture, and to the maximum machine sizes available to us on several other architectures. At similar accuracy, performance of VINE, used in GRAPE-tree mode, is approximately a factor 2 slower than that of VINE, used in host-only mode. Further optimizations of the GRAPE/host communications could improve the speed by as much as a factor of 3, but have not yet been implemented in VINE. Finally, we find that although parallel performance on small problems may reach a plateau beyond which more processors bring no additional speedup, performance never decreases, a factor important for running large simulations on many processors with individual time steps, where only a small fraction of the total particles require updates at any given moment.

Nelson, Andrew F. [Los Alamos National Laboratory, HPC-5, MS B272, Los Alamos, NM 87545 (United States); Wetzstein, M. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Naab, T. [Universitaets-Sternwarte, Scheinerstr. 1, 81679 Muenchen (Germany)], E-mail: andy.nelson@lanl.gov

2009-10-01T23:59:59.000Z

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

Performance of a parallel algebraic multilevel preconditioner for stabilized finite element semiconductor device modeling  

Science Conference Proceedings (OSTI)

In this study results are presented for the large-scale parallel performance of an algebraic multilevel preconditioner for solution of the drift-diffusion model for semiconductor devices. The preconditioner is the key numerical procedure determining ... Keywords: Drift-diffusion, Finite element, Graph partitioning, Multigrid, Multilevel preconditioners, Newton-Krylov, Nonsmoothed aggregation, Schwarz domain decomposition, Semiconductor devices

Paul T. Lin; John N. Shadid; Marzio Sala; Raymond S. Tuminaro; Gary L. Hennigan; Robert J. Hoekstra

2009-09-01T23:59:59.000Z

262

On a test of the modified BCS theory performance in the picket fence model  

E-Print Network (OSTI)

The errors in the arguments, numerical results, and conclusions in the paper "Test of a modified BCS theory performance in the picket fence model" [Nucl. Phys. A 822 (2009) 1] by V.Yu. Ponomarev and A.I. Vdovin are pointed out. Its repetitions of already published material are also discussed.

Nguyen Dinh Dang

2009-04-01T23:59:59.000Z

263

Numerical modeling of species transport in turbulent flow and experimental study on aerosol sampling  

E-Print Network (OSTI)

Numerical simulations were performed to study the turbulent mixing of a scalar species in straight tube, single and double elbow flow configurations. Different Reynolds Averaged Navier Stokes (RANS) and Large Eddy Simulation (LES) models were used to model the turbulence in the flow. Conventional and dynamic Smagorinsky sub-grid scale models were used for the LES simulations. Wall functions were used to resolve the near wall boundary layer. These simulations were run with both two-dimensional and three-dimensional geometries. The velocity and tracer gas concentration Coefficient of Variations were compared with experimental results. The results from the LES simulations compared better with experimental results than the results from the RANS simulations. The level of mixing downstream of a S-shaped double elbow was higher than either the single elbow or the U-shaped double elbow due to the presence of counter rotating vortices. Penetration of neutralized and non-neutralized aerosol particles through three different types of tubing was studied. The tubing used included standard PVC pipes, aluminum conduit and flexible vacuum hose. Penetration through the aluminum conduit was unaffected by the presence or absence of charge neutralization, whereas particle penetrations through the PVC pipe and the flexible hosing were affected by the amount of particle charge. The electric field in a space enclosed by a solid conductor is zero. Therefore charged particles within the conducting aluminum conduit do not experience any force due to ambient electric fields, whereas the charged particles within the non-conducting PVC pipe and flexible hose experience forces due to the ambient electric fields. This increases the deposition of charged particles compared to neutralized particles within the 1.5� PVC tube and 1.5� flexible hose. Deposition 2001a (McFarland et al. 2001) software was used to predict the penetration through transport lines. The prediction from the software compared well with experiments for all cases except when charged particles were transported through non-conducting materials. A Stairmand cyclone was designed for filtering out large particles at the entrance of the transport section.

Vijayaraghavan, Vishnu Karthik

2006-12-01T23:59:59.000Z

264

Parameter estimation for performance models of distributed application systems  

Science Conference Proceedings (OSTI)

The performance engineering of distributed applications requires models that capture contention for both hardware and software resources. Layered queueing models have been proposed for modeling distributed applications but they require model parameters ...

Jerome Rolia; Vidar Vetland

1995-11-01T23:59:59.000Z

265

Generation of an Hourly Meteorological Time Series for an Alpine Basin in British Columbia for Use in Numerical Hydrologic Modeling  

Science Conference Proceedings (OSTI)

Spatially distributed numerical hydrologic models are useful tools for examining the long-term impact of forest harvesting in mountainous basins on streamflow regime properties. Such models require the input of long-duration subdaily ...

Markus Schnorbus; Younes Alila

2004-10-01T23:59:59.000Z

266

Electrification of Stratiform Regions in Mesoscale Convective Systems. Part II: Two-Dimensional Numerical Model Simulations of a Symmetric MCS  

Science Conference Proceedings (OSTI)

Model simulations of a symmetric mesoscale convective system (MCS; observations discussed in Part I) were conducted using a 2D, time-dependent numerical model with bulk microphysics. A number of charging mechanisms were considered based on ...

Terry J. Schuur; Steven A. Rutledge

2000-07-01T23:59:59.000Z

267

Estimates of Turbulence from Numerical Weather Prediction Model Output with Applications to Turbulence Diagnosis and Data Assimilation  

Science Conference Proceedings (OSTI)

Estimates of small-scale turbulence from numerical model output are produced from local estimates of the spatial structure functions of model variables such as the velocity and temperature. The key assumptions used are the existence of a ...

Rod Frehlich; Robert Sharman

2004-10-01T23:59:59.000Z

268

A Numerical Modeling System of the Hydrological Cycle for Estimation of Water Fluxes in the Huaihe River Plain Region, China  

Science Conference Proceedings (OSTI)

To analyze the water budget under human influences in the Huaihe River plain region in China, the authors have developed a numerical modeling system that integrates water flux algorithms into a platform created by coupling a soil moisture model ...

Xi Chen; Yongqin David Chen; Zhicai Zhang

2007-08-01T23:59:59.000Z

269

Numerical Simulation of Thermal Performance of Floor Radiant Heating System with Enclosed Phase Change Material  

E-Print Network (OSTI)

In the present paper, a kind of enclosed phase change material (PCM) used in solar and low-temperature hot water radiant floor heating is investigated. On the basis of obtaining the best performance of PCM properties, a new radiant heating structure of the energy storage floor is designed,which places heat pipes in the enclosed phase change material (PCM) layer, without concrete in it. The PCM thermal storage time is studied in relation to the floor surface temperature under different low-temperature hot water temperatures. With the method of enthalpy , the PCM thermal storage time is studied under different supply water temperatures, supply water flows, distances between water wipe in the floor construction, floor covers and insulation conditions.

Qiu, L.; Wu, X.

2006-01-01T23:59:59.000Z

270

Numerical modeling of boiling due to production in a fractured reservoir and its field application  

Science Conference Proceedings (OSTI)

Numerical simulations were carried out to characterize the behaviors of fractured reservoirs under production which causes in-situ boiling. A radial flow model with a single production well, and a two-dimensional geothermal reservoir model with several production and injection wells were used to study the two-phase reservoir behavior. The behavior can be characterized mainly by the parameters such as the fracture spacing and matrix permeability. However, heterogeneous distribution of the steam saturation in the fracture and matrix regions brings about another complicated feature to problems of fractured two-phase reservoirs.

Yusaku Yano; Tsuneo Ishido

1995-01-26T23:59:59.000Z

271

Numerical modeling of plasma plume evolution against ambient background gas in laser blow off experiments  

Science Conference Proceedings (OSTI)

Two dimensional numerical modelling based on simplified hydrodynamic evolution for an expanding plasma plume (created by laser blow off) against an ambient background gas has been carried out. A comparison with experimental observations shows that these simulations capture most features of the plasma plume expansion. The plume location and other gross features are reproduced as per the experimental observation in quantitative detail. The plume shape evolution and its dependence on the ambient background gas are in good qualitative agreement with the experiment. This suggests that a simplified hydrodynamic expansion model is adequate for the description of plasma plume expansion.

Patel, Bhavesh G.; Das, Amita; Kaw, Predhiman; Singh, Rajesh; Kumar, Ajai [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

2012-07-15T23:59:59.000Z

272

Experiences with collaborative, distributed predictive human performance modeling  

Science Conference Proceedings (OSTI)

Although predictive human performance modeling has been researched for 30 years in HCI, to our knowledge modeling has been conducted as a solitary task of one modeler or, occasionally, two modelers working in tight face-to-face collaboration. In contrast, ... Keywords: cogtool, efficiency, klm, predictive human performance modeling, usability evaluation

Bonnie John; Sonal Starr; Brian Utesch

2012-05-01T23:59:59.000Z

273

Modeling Windows in Energy Plus with Simple Performance Indices  

E-Print Network (OSTI)

Modeling Windows in Energy Plus with Simple Performanceof California. Modeling Windows in Energy Plus with SimpleE+), cannot use standard window performance indices (U,

Arasteh, Dariush

2010-01-01T23:59:59.000Z

274

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

275

Influence of Air-Conditioning Waste Heat on Air Temperature in Tokyo during Summer: Numerical Experiments Using an Urban Canopy Model Coupled with a Building Energy Model  

Science Conference Proceedings (OSTI)

A coupled model consisting of a multilayer urban canopy model and a building energy analysis model has been developed to investigate the diurnal variations of outdoor air temperature in the office areas of Tokyo, Japan. Observations and numerical ...

Yukitaka Ohashi; Yutaka Genchi; Hiroaki Kondo; Yukihiro Kikegawa; Hiroshi Yoshikado; Yujiro Hirano

2007-01-01T23:59:59.000Z

276

The Successive-Order-of-Interaction Radiative Transfer Model. Part II: Model Performance and Applications  

Science Conference Proceedings (OSTI)

Radiative transfer models for scattering atmospheres that are accurate yet computationally efficient are required for many applications, such as data assimilation in numerical weather prediction. The successive-order-of-interaction (SOI) model is ...

Christopher W. O’Dell; Andrew K. Heidinger; Thomas Greenwald; Peter Bauer; Ralf Bennartz

2006-10-01T23:59:59.000Z

277

Numerical Modeling of Hydraulic Fracture Propagation Using Thermo-hydro-mechanical Analysis with Brittle Damage Model by Finite Element Method  

E-Print Network (OSTI)

Better understanding and control of crack growth direction during hydraulic fracturing are essential for enhancing productivity of geothermal and petroleum reservoirs. Structural analysis of fracture propagation and impact on fluid flow is a challenging issue because of the complexity of rock properties and physical aspects of rock failure and fracture growth. Realistic interpretation of the complex interactions between rock deformation, fluid flow, heat transfer, and fracture propagation induced by fluid injection is important for fracture network design. In this work, numerical models are developed to simulate rock failure and hydraulic fracture propagation. The influences of rock deformation, fluid flow, and heat transfer on fracturing processes are studied using a coupled thermo-hydro-mechanical (THM) analysis. The models are used to simulate microscopic and macroscopic fracture behaviors of laboratory-scale uniaxial and triaxial experiments on rock using an elastic/brittle damage model considering a stochastic heterogeneity distribution. The constitutive modeling by the energy release rate-based damage evolution allows characterizing brittle rock failure and strength degradation. This approach is then used to simulate the sequential process of heterogeneous rock failures from the initiation of microcracks to the growth of macrocracks. The hydraulic fracturing path, especially for fractures emanating from inclined wellbores and closed natural fractures, often involves mixed mode fracture propagation. Especially, when the fracture is inclined in a 3D stress field, the propagation cannot be modeled using 2D fracture models. Hence, 2D/3D mixed-modes fracture growth from an initially embedded circular crack is studied using the damage mechanics approach implemented in a finite element method. As a practical problem, hydraulic fracturing stimulation often involves fluid pressure change caused by injected fracturing fluid, fluid leakoff, and fracture propagation with brittle rock behavior and stress heterogeneities. In this dissertation, hydraulic fracture propagation is simulated using a coupled fluid flow/diffusion and rock deformation analysis. Later THM analysis is also carried out. The hydraulic forces in extended fractures are solved using a lubrication equation. Using a new moving-boundary element partition methodology (EPM), fracture propagation through heterogeneous media is predicted simply and efficiently. The method allows coupling fluid flow and rock deformation, and fracture propagation using the lubrication equation to solve for the fluid pressure through newly propagating crack paths. Using the proposed model, the 2D/3D hydraulic fracturing simulations are performed to investigate the role of material and rock heterogeneity. Furthermore, in geothermal and petroleum reservoir design, engineers can take advantage of thermal fracturing that occurs when heat transfers between injected flow and the rock matrix to create reservoir permeability. These thermal stresses are calculated using coupled THM analysis and their influence on crack propagation during reservoir stimulation are investigated using damage mechanics and thermal loading algorithms for newly fractured surfaces.

Min, Kyoung

2013-08-01T23:59:59.000Z

278

A Numerical Study of a Mesoscale Convective System during TOGA COARE. Part I: Model Description and Verification  

Science Conference Proceedings (OSTI)

A 16-h numerical simulation of the growing and mature stages of the 15 December 1992 Tropical Ocean Global Atmosphere Coupled Ocean–Atmosphere Response Experiment (TOGA COARE) mesoscale convective system (MCS) is performed to demonstrate the ...

Badrinath Nagarajan; M. K. Yau; Da-Lin Zhang

2001-10-01T23:59:59.000Z

279

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

280

Exploiting multi-scale parallelism for large scale numerical modelling of laser wakefield accelerators  

E-Print Network (OSTI)

A new generation of laser wakefield accelerators, supported by the extreme accelerating fields generated in the interaction of PW-Class lasers and underdense targets, promises the production of high quality electron beams in short distances for multiple applications. Achieving this goal will rely heavily on numerical modeling for further understanding of the underlying physics and identification of optimal regimes, but large scale modeling of these scenarios is computationally heavy and requires efficient use of state-of-the-art Petascale supercomputing systems. We discuss the main difficulties involved in running these simulations and the new developments implemented in the OSIRIS framework to address these issues, ranging from multi-dimensional dynamic load balancing and hybrid distributed / shared memory parallelism to the vectorization of the PIC algorithm. We present the results of the OASCR Joule Metric program on the issue of large scale modeling of LWFA, demonstrating speedups of over 1 order of magni...

Fonseca, Ricardo A; Fiúza, Frederico; Davidson, Asher; Tsung, Frank S; Mori, Warren B; Silva, Luís O

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.


281

A particle numerical model for wall film dynamics in port-injected engines  

DOE Green Energy (OSTI)

To help predict hydrocarbon emissions during cold-start conditions the authors are developing a numerical model for the dynamics and vaporization of the liquid wall films formed in port-injected spark-ignition engines and incorporating this model in the KIVA-3 code for complex geometries. This paper summarizes the current status of the project and presents illustrative example calculations. The dynamics of the wall film is influenced by interactions with the impinging spray, the wall, and the gas flow near the wall. The spray influences the film through mass, tangential momentum, and energy addition. The wall affects the film through the no-slip boundary condition and heat transfer. The gas alters film dynamics through tangential stresses and heat and mass transfer in the gas boundary layers above the films. New wall functions are given to predict transport in the boundary layers above the vaporizing films. It is assumed the films are sufficiently thin that film flow is laminar and that liquid inertial forces are negligible. Because liquid Prandtl numbers are typically about then, unsteady heating of the film should be important and is accounted for by the model. The thin film approximation breaks down near sharp corners, where an inertial separation criterion is used. A particle numerical method is used for the wall film. This has the advantages of compatibility with the KIVA-3 spray model and of very accurate calculation of convective transport of the film. The authors have incorporated the wall film model into KIVA-3, and the resulting combined model can be used to simulate the coupled port and cylinder flows in modern spark-ignition engines. They give examples by comparing computed fuel distributions with closed- and open-valve injection during the intake and compression strokes of a generic two-valve engine.

O`Rourke, P.J.; Amsden, A.A.

1996-09-01T23:59:59.000Z

282

TOUGH: a numerical model for nonisothermal unsaturated flow to study waste canister heating effects  

Science Conference Proceedings (OSTI)

The physical processes modeled and the mathematical and numerical methods employed in a simulator for non-isothermal flow of water, vapor, and air in permeable media are briefly summarized. The simulator has been applied to study thermo-hydrological conditions in the near vicinity of high-level nuclear waste packages emplaced in unsaturated rocks. The studies reported here specifically address the question whether or not the waste canister environment will dry up in the thermal phase. 13 references, 8 figures, 2 tables.

Pruess, K.; Wang, J.S.Y.

1983-12-01T23:59:59.000Z

283

Leaking method approach to surface transport in the Mediterranean Sea from a numerical ocean model  

E-Print Network (OSTI)

We use Lagrangian diagnostics (the leaking and the exchange methods) to characterize surface transport out of and between selected regions in the Western Mediterranean. Velocity fields are obtained from a numerical model. Residence times of water of Atlantic origin in the Algerian basin, with a strong seasonal dependence, are calculated. Exchange rates between these waters and the ones occupying the northern basin are also evaluated. At surface, northward transport is dominant, and involves filamental features and eddy structures that can be identified with the Algerian eddies. The impact on these results of the presence of small scale turbulent motions is evaluated by adding Lagrangian diffusion.

Judit Schneider; Vicente Fernandez; Emilio Hernandez-Garcia

2004-10-01T23:59:59.000Z

284

Original article: Comparison of numerical models in radiative heat transfer with application to circuit-breaker simulations  

Science Conference Proceedings (OSTI)

Two different modeling approaches for the numerical computation of the radiation energy exchange in the context of the simulation of high-voltage circuit breakers are investigated. These are the basic Radiative Transfer Equation method and the P1 model ... Keywords: CFD modeling, Circuit breakers, Finite volume discretization, P1 model, Radiative heat transfer

Matthieu Melot; Jean-Yves TréPanier; Ricardo Camarero; Eddy Petro

2012-08-01T23:59:59.000Z

285

Supercomputer and cluster performance modeling and analysis efforts:2004-2006.  

Science Conference Proceedings (OSTI)

This report describes efforts by the Performance Modeling and Analysis Team to investigate performance characteristics of Sandia's engineering and scientific applications on the ASC capability and advanced architecture supercomputers, and Sandia's capacity Linux clusters. Efforts to model various aspects of these computers are also discussed. The goals of these efforts are to quantify and compare Sandia's supercomputer and cluster performance characteristics; to reveal strengths and weaknesses in such systems; and to predict performance characteristics of, and provide guidelines for, future acquisitions and follow-on systems. Described herein are the results obtained from running benchmarks and applications to extract performance characteristics and comparisons, as well as modeling efforts, obtained during the time period 2004-2006. The format of the report, with hypertext links to numerous additional documents, purposefully minimizes the document size needed to disseminate the extensive results from our research.

Sturtevant, Judith E.; Ganti, Anand; Meyer, Harold (Hal) Edward; Stevenson, Joel O.; Benner, Robert E., Jr. (.,; .); Goudy, Susan Phelps; Doerfler, Douglas W.; Domino, Stefan Paul; Taylor, Mark A.; Malins, Robert Joseph; Scott, Ryan T.; Barnette, Daniel Wayne; Rajan, Mahesh; Ang, James Alfred; Black, Amalia Rebecca; Laub, Thomas William; Vaughan, Courtenay Thomas; Franke, Brian Claude

2007-02-01T23:59:59.000Z

286

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

E-Print Network (OSTI)

A numerical investigation of laminar forced convective heat transfer was performed in a three-dimensional channel with baffles in which a uniform heat flux was applied to the top and bottom walls, and the side walls were considered adiabatic. The trade-off between heat transfer enhancement and pressure drop produced by the baffles was studied for periodically fully developed flow (PDF). The numerical analysis was performed using a finite volume approach. The computer code was validated against the experimental results of Goldstein and Kreid (1967) and Beavers et. al. (1970) for a three-dimensional laminar flow in a channel without baffles. Parametric runs were made for Reynolds Numbers (Re) of 150, 250, 3 50, and 450, for blockage ratios (H/Dy) of 0. 5, 0.6, 0. 7, 0.8. Heat transfer behavior was studied for Prandtl Numbers (Pr) of 0. 7 and 7. 0, and for wall thermal conductivity to fluid thermal conductivity ratios (K) of 1, 10, 100 and 1000. It was found that three dimensional effects were present for the range of Reynolds number studied. The pressure drop penalty becomes highly important above blockage ratios of 0.7. Higher heat transfer enhancement was found for high Prandtl numbers (Pr--7. 0) than for low Prandtl numbers (Pr--O. 7). The heat transfer enhancement due to an increase in the thermal conductivity ratio of the solid to the fluid regions is greater than the one obtained by increasing the blockage ratio.

Lopez Buso, Jorge Ricardo

1995-01-01T23:59:59.000Z

287

Analytical Modeling and Performance Prediction of Remanufactured ...  

Science Conference Proceedings (OSTI)

The CLP tool assists in remanufacturing of high value, high demand rotorcraft, automotive and wind turbine gears. This paper will summarize the CLP models ...

288

Detailed Performance Model for Photovoltaic Systems: Preprint  

DOE Green Energy (OSTI)

This paper presents a modified current-voltage relationship for the single diode model. The single-diode model has been derived from the well-known equivalent circuit for a single photovoltaic cell. The modification presented in this paper accounts for both parallel and series connections in an array.

Tian, H.; Mancilla-David, F.; Ellis, K.; Muljadi, E.; Jenkins, P.

2012-07-01T23:59:59.000Z

289

Hidden-Articulator Markov Models: Performance  

E-Print Network (OSTI)

A Hidden-Articulator Markov Model (HAMM) is a Hidden Markov Model (HMM) in which each state represents an articulatory configuration. Articulatory knowledge, known to be useful for speech recognition [4], is represented by specifying a mapping of phonemes to articulatory configurations; vocal tract dynamics are represented via transitions between articulatory configurations.

Improvements And Robustness

2000-01-01T23:59:59.000Z

290

Statistical Significance Testing in Numerical Weather Prediction  

Science Conference Proceedings (OSTI)

Experiments are often performed with numerical forecast models to determine the response to a changed model formulation, initial conditions or boundary conditions. Such experiments are inherently subject to sampling error and it is not always ...

Roger Daley; Robert M. Chervin

1985-05-01T23:59:59.000Z

291

Modeling Agents that Exhibit Variable Performance in a Collaborative Setting  

E-Print Network (OSTI)

Abstract. In a collaborative environment, knowledge about collaborators ’ skills is an important factor when determining which team members should perform a task. However, this knowledge may be incomplete or uncertain. In this paper, we extend our ETAPP (Environment-Task-Agents-Policy-Protocol) collaboration framework by modeling team members that exhibit non-deterministic performance, and comparing two alternative ways of using these models to assign agents to tasks. Our simulation-based evaluation shows that performance variability has a large impact on task performance, and that task performance is improved by consulting agent models built from a small number of observations of agents’ recent performance. 1

Ingrid Zukerman; Christian Guttmann

2005-01-01T23:59:59.000Z

292

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

293

A Three-Dimensional Numerical Model of an Isolated Thunderstorm. Part II: Dynamics of Updraft Splitting and Mesovortex Couplet Evolution  

Science Conference Proceedings (OSTI)

This study analyzes the dynamics of an isolated convective storm embedded within marked ambient vertical wind shear dominated by low-level veering, as simulated by a three-dimensional anelastic numerical modeling experiment. Two particular ...

Robert E. Schlesinger

1980-02-01T23:59:59.000Z

294

High-Order Numerics in an Unstaggered Three-Dimensional Time-Split Semi-Lagrangian Forecast Model  

Science Conference Proceedings (OSTI)

Traditional finite-difference numerical forecast models usually employ relatively low-order approximations on grids staggered in both the horizontal and the vertical. In a previous study, Purser and Leslie (1988) demonstrated that high-order ...

L. M. Leslie; R. J. Purser

1991-07-01T23:59:59.000Z

295

Mesoscale Numerical Weather Prediction Models Used in Support of Infrared Hyperspectral Measurement Simulation and Product Algorithm Development  

Science Conference Proceedings (OSTI)

A novel application of numerical weather prediction (NWP) models within an end-to-end processing system used to demonstrate advanced hyperspectral satellite technologies and instrument concepts is presented. As part of this system, sophisticated ...

Jason A. Otkin; Derek J. Posselt; Erik R. Olson; Hung-Lung Huang; James E. Davies; Jun Li; Christopher S. Velden

2007-04-01T23:59:59.000Z

296

On the Numerical Implementation of Advection Schemes for Use in Conjunction with Various Mixing Parameterizations in the GFDL Ocean Model  

Science Conference Proceedings (OSTI)

The results from ocean model experiments conducted with isopycnal and isopycnal thickness diffusion parameterizations for subgrid-scale mixing associated with mesoscale eddies are examined from a numerical standpoint. It is shown that when the ...

Andrew J. Weaver; Michael Eby

1997-02-01T23:59:59.000Z

297

Numerical Sensitivity Experiments of Varying Model Physics on the Structure, Evolution and Dynamics of Two Mesoscale Convective Systems  

Science Conference Proceedings (OSTI)

The effects of different model physics and different convective and boundary layer parameterization schemes are investigated using an 18-h nested-grid numerical simulation of the mesoscale convective systems (MCSs) that were responsible for the ...

Da-Lin Zhang; J. Michael Fritsch

1988-01-01T23:59:59.000Z

298

A High-Resolution Topographic Correction Method for Clear-Sky Solar Irradiance Derived with a Numerical Weather Prediction Model  

Science Conference Proceedings (OSTI)

Rugged terrain is a source of variability in the incoming solar radiation field, but the influence of terrain is still not properly included by most current numerical weather prediction (NWP) models. In this work, a downscaling postprocessing ...

José A. Ruiz-Arias; David Pozo-Vázquez; Vicente Lara-Fanego; Francisco J. Santos-Alamillos; J. Tovar-Pescador

2011-12-01T23:59:59.000Z

299

Fast 2D non-LTE radiative modelling of prominences I. Numerical methods and benchmark results  

E-Print Network (OSTI)

New high-resolution spectropolarimetric observations of solar prominences require improved radiative modelling capabilities in order to take into account both multi-dimensional - at least 2D - geometry and complex atomic models. This makes necessary the use of very fast numerical schemes for the resolution of 2D non-LTE radiative transfer problems considering freestanding and illuminated slabs. The implementation of Gauss-Seidel and successive over-relaxation iterative schemes in 2D, together with a multi-grid algorithm, is thoroughly described in the frame of the short characteristics method for the computation of the formal solution of the radiative transfer equation in cartesian geometry. We propose a new test for multidimensional radiative transfer codes and we also provide original benchmark results for simple 2D multilevel atom cases which should be helpful for the further development of such radiative transfer codes, in general.

L. Leger; L. Chevallier; F. Paletou

2007-03-27T23:59:59.000Z

300

A Numerical Model for Chemical and Meteorological Processes in the Atmospheric Boundary Layer. Part I: A Model Description and a One-Dimensional Parameter Study  

Science Conference Proceedings (OSTI)

A numerical flow model is presented for the atmospheric boundary layer, including dispersion and chemical transformations of air pollutants. The model is a three-dimensional time-dependent one for the mesoscale based on the conservation equations ...

Gunilla Svensson

1996-06-01T23:59:59.000Z

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

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

DOE Green Energy (OSTI)

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

302

Electrical, Frequency and Thermal Measurement and Modelling of Supercapacitor Performance  

E-Print Network (OSTI)

Electrical, Frequency and Thermal Measurement and Modelling of Supercapacitor Performance Yasser--This paper presents an evaluation of commercial supercapacitors performance (ESR, C, self-discharge, Pmax, Emax, coulumbic efficiency, etc), under different conditions. Characterization of supercapacitor

Paris-Sud XI, Université de

303

Numerical Models of Boundary Layer Processes over and around the Gulf of Mexico during a Return-Flow Event  

Science Conference Proceedings (OSTI)

The return-flow of low-level air from the Gulf of Mexico over the southeast United States during the cool season is studied using numerical models. The key models are a newly developed airmass transformation (AMT) model and a one-dimensional ...

A. Birol Kara; James B. Elsner; Paul H. Ruscher

1998-12-01T23:59:59.000Z

304

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

305

DISCL group Performance Model Directed Data Sieving  

E-Print Network (OSTI)

--control code for a thermo- stat and a nuclear reactor. We then pass the generated automata to the HyTech model prototype--written in MATLAB. We analyzed the control code for a simple thermostat and for a nuclear reactor. The theory of hybrid automata. In Logic in Computer Science, 1996. LICS '96. Proceedings., Eleventh

Gelfond, Michael

306

Grid Performance Metrics Using Model-less Algorithms Pete Sauer...  

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

- Grid Performance Metrics Using Model-less Algorithms Pete Sauer and Alejandro D. Domnguez-Garca Department of Electrical and Computer Engineering University of Illinois at...

307

Hypercube performance for 2-D seismic finite-difference modeling  

Science Conference Proceedings (OSTI)

Wave-equation seismic modeling in two space dimensions is computationally intensive, often requiring hours of supercomputer CPU time to run typical geological models with 500 × 500 grids and 100 sources. This paper analyzes the performance of ACOUS2D, ...

L. J. Baker

1989-01-01T23:59:59.000Z

308

Numerical Experiments with a General Circulation Model Concerning the Distribution of Ozone in the Stratosphere  

Science Conference Proceedings (OSTI)

Two experiments were performed with a nine-layer quasi-geostrophic spectral model to simulate the distribution of ozone below 60 km. Experiment I included thermal and orographic forcing of the planetary-scale waves while Experiment II did not ...

R. J. Kurzeja; K. V. Haggard; W. L. Grose

1984-07-01T23:59:59.000Z

309

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.

310

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

311

Performance model assessment for multi-junction concentrating photovoltaic systems.  

DOE Green Energy (OSTI)

Four approaches to modeling multi-junction concentrating photovoltaic system performance are assessed by comparing modeled performance to measured performance. Measured weather, irradiance, and system performance data were collected on two systems over a one month period. Residual analysis is used to assess the models and to identify opportunities for model improvement. Large photovoltaic systems are typically developed as projects which supply electricity to a utility and are owned by independent power producers. Obtaining financing at favorable rates and attracting investors requires confidence in the projected energy yield from the plant. In this paper, various performance models for projecting annual energy yield from Concentrating Photovoltaic (CPV) systems are assessed by comparing measured system output to model predictions based on measured weather and irradiance data. The results are statistically analyzed to identify systematic error sources.

Stein, Joshua S.; Riley, Daniel M.; McConnell, Robert. (Amonix, Inc., Seal Beach, CA); Sahm, Aaron (University of Nevada, Las Vegas, NV); Crawford, Clark (Amonix, Inc., Seal Beach, CA); King, David L.; Cameron, Christopher P.; Foresi, James S. (Emcore, Inc., Albuquerque, NM)

2010-03-01T23:59:59.000Z

312

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

313

Hybrid Model of Existing Buildings for Transient Thermal Performance Estimation  

E-Print Network (OSTI)

Building level energy models are important to provide accurate prediction of energy consumption for building performance diagnosis and energy efficiency assessment of retrofitting alternatives for building performance upgrading. Simplified but physically meaningful models for existing buildings are preferable for practical applications. In this study, a hybrid building model is developed to describe building system for thermal performance prediction at building level. The model includes two parts. One part is the detailed physical models, which are the CTF models of building envelopes based on the easily available coincident detailed physical properties. The other part is the simplified 2R2C model for building internal mass, whose parameters are estimated and optimized using short-term monitored operation data. A genetic algorithm estimator is developed to optimize these parameters. The parameter optimization of the simplified model and the hybrid building model are validated in a high-rise commercial office building under various weather conditions.

Xu, X.; Wang, S.

2006-01-01T23:59:59.000Z

314

Development of analytical and numerical models for the assessment and interpretation of hydrogeological field tests  

Science Conference Proceedings (OSTI)

Mathematical models of the flow and tracer tests in fractured aquifers are being developed for the further study of radioactive wastes migration in round water at the Lake Area, which is associated with one of the waste disposal site in Russia. The choice of testing methods, tracer types (chemical or thermal) and the appropriate models are determined by the nature of the ongoing ground-water pollution processes and the hydrogeological features of the site under consideration. Special importance is attached to the increased density of wastes as well as to the possible redistribution of solutes both in the liquid phase and in the absorbed state (largely, on fracture surfaces). This allows for studying physical-and-chemical (hydrogeochemical) interaction parameters which are hard to obtain (considering a fractured structure of the rock mass) in laboratory. Moreover, a theoretical substantiation is being given to the field methods of studying the properties of a fractured stratum aimed at the further construction of the drainage system or the subsurface flow barrier (cutoff wall), as well as the monitoring system that will evaluate the reliability of these ground-water protection measures. The proposed mathematical models are based on a tight combination of analytical and numerical methods, the former being preferred in solving the principal (2D axisymmetrical) class of the problems. The choice of appropriate problems is based on the close feedback with subsequent field tests in the Lake Area. 63 refs.

Mironenko, V.A.; Rumynin, V.G.; Konosavsky, P.K. [St. Petersburg Mining Inst. (Russian Federation); Pozdniakov, S.P.; Shestakov, V.M. [Moscow State Univ. (Russian Federation); Roshal, A.A. [Geosoft-Eastlink, Moscow (Russian Federation)

1994-07-01T23:59:59.000Z

315

PMPS(3): a performance model of parallel systems  

Science Conference Proceedings (OSTI)

In this paper, an open performance model framework PMPS(n) and a realization of this framework PMPS(3), including memory, I/O and network, are presented and used to predict runtime of NPB benchmarks on P4 cluster. The experimental results demonstrates ... Keywords: I/O, convolution methods, parallel, performance model

Chen Yong-ran; Qi Xing-yun; Qian Yue; Dou Wen-hua

2006-09-01T23:59:59.000Z

316

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

317

A Performance Modeling and Evaluation of the Cambridge Fast Ring  

Science Conference Proceedings (OSTI)

Performance of the Cambridge Fast Ring (CFR), a high-speed slotted ring with normal slots, is studied. It is shown that the CFR can be represented by a multiqueue multiple cyclic server model with a 1-limited service discipline and with a restriction ... Keywords: 1-limited service discipline, Cambridge Fast Ring, approximate analytic M/G/1 vacation model, exact necessary and sufficient stability conditions, high-speed slotted ring, local area networks, message waiting times, multiqueue multiple cyclic server model, normal slots, performance evaluation, performance modeling, queueing theory., vacation period

Mirjana Zafirovic-Vukotic; Ignas G. Niemegeers

1992-09-01T23:59:59.000Z

318

Original article: Estimation of spatially varying open boundary conditions for a numerical internal tidal model with adjoint method  

Science Conference Proceedings (OSTI)

The adjoint data assimilation technique is applied to the estimation of the spatially varying open boundary conditions (OBCs) for a numerical internal tidal model. The spatial variation of the OBCs is realized by the so-called 'independent point scheme' ... Keywords: Adjoint method, Internal tidal model, Open boundary conditions, Parameter estimation, Spatial variation

Haibo Chen, Anzhou Cao, Jicai Zhang, Chunbao Miao, Xianqing Lv

2014-03-01T23:59:59.000Z

319

Efficient Numerical Methods for an Anisotropic, Nonisothermal, Two-Phase Transport Model of Proton Exchange Membrane Fuel Cell  

Science Conference Proceedings (OSTI)

We carry out model and numerical studies for a three-dimensional, anisotropic, nonisothermal, two-phase steady state transport model of proton exchange membrane fuel cell (PEMFC) in this paper. Besides fully addressing the conservation equations of mass, ... Keywords: Anisotropy, Combined finite element-upwind finite volume, Kirchhoff transformation, Newton's linearization, Nonisothermality, Proton exchange membrane fuel cell (PEMFC), Two-phase transport

Pengtao Sun

2012-04-01T23:59:59.000Z

320

Cost and Performance Assumptions for Modeling Electricity Generation Technologies  

Science Conference Proceedings (OSTI)

The goal of this project was to compare and contrast utility scale power plant characteristics used in data sets that support energy market models. Characteristics include both technology cost and technology performance projections to the year 2050. Cost parameters include installed capital costs and operation and maintenance (O&M) costs. Performance parameters include plant size, heat rate, capacity factor or availability factor, and plant lifetime. Conventional, renewable, and emerging electricity generating technologies were considered. Six data sets, each associated with a different model, were selected. Two of the data sets represent modeled results, not direct model inputs. These two data sets include cost and performance improvements that result from increased deployment as well as resulting capacity factors estimated from particular model runs; other data sets represent model input data. For the technologies contained in each data set, the levelized cost of energy (LCOE) was also evaluated, according to published cost, performance, and fuel assumptions.

Tidball, R.; Bluestein, J.; Rodriguez, N.; Knoke, S.

2010-11-01T23:59:59.000Z

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.


321

COMMIX-PPC: A three-dimensional transient multicomponent computer program for analyzing performance of power plant condensers. Volume 1, Equations and numerics  

SciTech Connect

The COMMIX-PPC computer pregrain is an extended and improved version of earlier COMMIX codes and is specifically designed for evaluating the thermal performance of power plant condensers. The COMMIX codes are general-purpose computer programs for the analysis of fluid flow and heat transfer in complex Industrial systems. In COMMIX-PPC, two major features have been added to previously published COMMIX codes. One feature is the incorporation of one-dimensional equations of conservation of mass, momentum, and energy on the tube stile and the proper accounting for the thermal interaction between shell and tube side through the porous-medium approach. The other added feature is the extension of the three-dimensional conservation equations for shell-side flow to treat the flow of a multicomponent medium. COMMIX-PPC is designed to perform steady-state and transient. Three-dimensional analysis of fluid flow with heat transfer tn a power plant condenser. However, the code is designed in a generalized fashion so that, with some modification, it can be used to analyze processes in any heat exchanger or other single-phase engineering applications. Volume I (Equations and Numerics) of this report describes in detail the basic equations, formulation, solution procedures, and models for a phenomena. Volume II (User`s Guide and Manual) contains the input instruction, flow charts, sample problems, and descriptions of available options and boundary conditions.

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

1993-02-01T23:59:59.000Z

322

A standardized approach to PV system performance model validation.  

DOE Green Energy (OSTI)

PV performance models are used to predict how much energy a PV system will produce at a given location and subject to prescribed weather conditions. These models are commonly used by project developers to choose between module technologies and array designs (e.g., fixed tilt vs. tracking) for a given site or to choose between different geographic locations, and are used by the financial community to establish project viability. Available models can differ significantly in their underlying mathematical formulations and assumptions and in the options available to the analyst for setting up a simulation. Some models lack complete documentation and transparency, which can result in confusion on how to properly set up, run, and document a simulation. Furthermore, the quality and associated uncertainty of the available data upon which these models rely (e.g., irradiance, module parameters, etc.) is often quite variable and frequently undefined. For these reasons, many project developers and other industry users of these simulation tools have expressed concerns related to the confidence they place in PV performance model results. To address this problem, we propose a standardized method for the validation of PV system-level performance models and a set of guidelines for setting up these models and reporting results. This paper describes the basic elements for a standardized model validation process adapted especially for PV performance models, suggests a framework to implement the process, and presents an example of its application to a number of available PV performance models.

Stein, Joshua S.; Jester, Terry (Hudson Clean Energy Partners); Posbic, Jean (BP Solar); Kimber, Adrianne (First Solar); Cameron, Christopher P.; Bourne, Benjamin (SunPower Corporation)

2010-10-01T23:59:59.000Z

323

Baryon history and cosmic star formation in non-Gaussian cosmological models: numerical simulations  

E-Print Network (OSTI)

We present the first numerical, N-body, hydrodynamical, chemical simulations of cosmic structure formation in the framework of non-Gaussian models. We study the impact of primordial non-Gaussianities on early chemistry (e, H, H+, H-, He, He+, He++, H2, H2+, D, D+, HD, HeH+), molecular and atomic gas cooling, star formation, metal (C, O, Si, Fe, Mg, S) enrichment, population III (popIII) and population II-I (popII) transition, and on the evolution of "visible" objects. We find that non-Gaussianities can have some consequences on baryonic structure formation at very early epochs, but the subsequent evolution at later times washes out any difference among the various models. When assuming reasonable values for primordial non-Gaussian perturbations, it turns out that they are responsible for: (i) altering early molecular fractions in the cold, dense gas phase of ~10 per cent; (ii) inducing small temperature fluctuations of ~15, and of the popIII/popII transition of up to some 10^7yr; (iv) determining variations of history of the Universe. We stress, though, that purely non-Gaussian effects might be difficult to address, since they are strictly twisted with additional physical phenomena (e.g. primordial gas bulk flows, unknown primordial popIII stellar mass function, etc.) that have similar or stronger impact on the behaviour of the baryons.

Umberto Maio; Francesca Iannuzzi

2011-03-16T23:59:59.000Z

324

Numerical modeling of the elution peak profiles of retained solutes in supercritical fluid chromatography  

Science Conference Proceedings (OSTI)

In supercritical fluid chromatography (SFC), the significant expansion of the mobile phase along the column causes the formation of axial and radial gradients of temperature. Due to these gradients, the mobile phase density, its viscosity, its velocity, its diffusion coefficients, etc. are not constant throughout the column. This results in a nonuniform flow velocity distribution, itself causing a loss of column efficiency in certain cases, even at low flow rates, as they do in HPLC. At high flow rates, an important deformation of the elution profiles of the sample components may occur. The model previously used to account satisfactorily for the retention of an unsorbed solute in SFC is applied to the modeling of the elution peak profiles of retained compounds. The numerical solution of the combined heat and mass balance equations provides the temperature and the pressure profiles inside the column and values of the retention time and the band profiles of retained compounds that are in excellent agreement with independent experimental data for large value of mobile phase reduced density. At low reduced densities, the band profiles can strongly depend on the column axial distribution of porosity.

Kaczmarski, Krzysztof [University of Tennessee and Rzeszow University of Technology, Poland; Guiochon, Georges A [ORNL

2011-01-01T23:59:59.000Z

325

Numerical study of the disordered Poland-Scheraga model of DNA denaturation  

E-Print Network (OSTI)

We numerically study the binary disordered Poland-Scheraga model of DNA denaturation, in the regime where the pure model displays a first order transition (loop exponent $c=2.15>2$). We use a Fixman-Freire scheme for the entropy of loops and consider chain length up to $N=4 \\cdot 10^5$, with averages over $10^4$ samples. We present in parallel the results of various observables for two boundary conditions, namely bound-bound (bb) and bound-unbound (bu), because they present very different finite-size behaviors, both in the pure case and in the disordered case. Our main conclusion is that the transition remains first order in the disordered case: in the (bu) case, the disorder averaged energy and contact densities present crossings for different values of $N$ without rescaling. In addition, we obtain that these disorder averaged observables do not satisfy finite size scaling, as a consequence of strong sample to sample fluctuations of the pseudo-critical temperature. For a given sample, we propose a procedure to identify its pseudo-critical temperature, and show that this sample then obeys first order transition finite size scaling behavior. Finally, we obtain that the disorder averaged critical loop distribution is still governed by $P(l) \\sim 1/l^c$ in the regime $l \\ll N$, as in the pure case.

Thomas Garel; Cecile Monthus

2005-04-05T23:59:59.000Z

326

Renewable Fuels Module, Appendix - Model Performance, Model Documentation  

Reports and Publications (EIA)

This appendix discusses performance aspects of the Renewable Fuels Module (RFM). It is intended to present the pattern of response of the RFM to typical changes in its major inputs from other NEMS modules.

Perry M. Lindstrom

1995-06-01T23:59:59.000Z

327

Final Report: Performance Modeling Activities in PERC2  

Science Conference Proceedings (OSTI)

Progress in Performance Modeling for PERC2 resulted in: • Automated modeling tools that are robust, able to characterize large applications running at scale while simultaneously simulating the memory hierarchies of mul-tiple machines in parallel. • Porting of the requisite tracer tools to multiple platforms. • Improved performance models by using higher resolution memory models that ever before. • Adding control-flow and data dependency analysis to the tracers used in perform-ance tools. • Exploring and developing several new modeling methodologies. • Using modeling tools to develop performance models for strategic codes. • Application of modeling methodology to make a large number of “blind” per-formance predictions on certain mission partner applications, targeting most cur-rently available system architectures. • Error analysis to correct some systematic biases encountered as part of the large-scale blind prediction exercises. • Addition of instrumentation capabilities for communication libraries other than MPI. • Dissemination the tools and modeling methods to several mission partners, in-cluding DoD HPCMO and two DARPA HPCS vendors (Cray and IBM), as well as to the wider HPC community via a series of tutorials.

Allan Snavely

2007-02-25T23:59:59.000Z

328

Modeling performance of horizontal, undulating, and multilateral wells  

E-Print Network (OSTI)

Horizontal, undulating, and multilateral wells are relatively new alternatives in field development because they can increase the productivity per well and reduce the cost of field development. Because the feasibility of these wells may not be valid in some reservoirs, well performance should be verified before making decisions. Undulation is usually associated to horizontal wells with some degrees. Existing inflow performance models do not account for the undulation of the well, which can cause significant error and economic loss. Moreover, some of the inflow models ignore pressure drop along the lateral, which is definitely not true in high production and long lateral wells. The inflow performance models of horizontal, undulating, and multilateral wells are developed in this study. The models can be divided into two main categories: the closed form model and the line source model. The closed form model applies for relatively low vertical permeability formations for the single-phase system and twophase system. The model is flexible and easy to apply with reasonable accuracy. The line source model does not have any restrictions with permeability. The model applies for single-phase system. The model is very accurate and easy to use. Both models can be applied to various well trajectories with realizable accuracy. As a result of this study, the well performance of unconventional well trajectories can be predicted and optimized.

Kamkom, Rungtip

2007-08-01T23:59:59.000Z

329

Improving the performance scalability of the community atmosphere model  

Science Conference Proceedings (OSTI)

The Community Atmosphere Model (CAM), which serves as the atmosphere component of the Community Climate System Model (CCSM), is the most computationally expensive CCSM component in typical configurations. On current and next-generation leadership class ... Keywords: CAM, atmospheric modeling, massively parallel computing, performance, scalability

Arthur A. Mirin; Patrick H. Worley

2012-02-01T23:59:59.000Z

330

Performance and Dependability Modeling with Mobius Shravan Gaonkar1  

E-Print Network (OSTI)

Model PV Editor Editor Study Main Application Figure 1: M¨obius architecture from users perspec- tivePerformance and Dependability Modeling with M¨obius Shravan Gaonkar1 , Ken Keefe1 , Ruth Lamprecht2¨obius is a multi-paradigm multi-solution framework to de- scribe and analyze stochastic models of discrete-event dy

Illinois at Urbana-Champaign, University of

331

Performance model for grid-connected photovoltaic inverters.  

SciTech Connect

This document provides an empirically based performance model for grid-connected photovoltaic inverters used for system performance (energy) modeling and for continuous monitoring of inverter performance during system operation. The versatility and accuracy of the model were validated for a variety of both residential and commercial size inverters. Default parameters for the model can be obtained from manufacturers specification sheets, and the accuracy of the model can be further refined using measurements from either well-instrumented field measurements in operational systems or using detailed measurements from a recognized testing laboratory. An initial database of inverter performance parameters was developed based on measurements conducted at Sandia National Laboratories and at laboratories supporting the solar programs of the California Energy Commission.

Boyson, William Earl; Galbraith, Gary M.; King, David L.; Gonzalez, Sigifredo

2007-09-01T23:59:59.000Z

332

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

E-Print Network (OSTI)

The Unidirectional Hybrid Wave Model (UHWM) predicts irregular wave kinematics and pressure accurately in comparison with its linear counterpart and modification, especially near the free surface. Hence, in using the Morrison equation it has been employed in the computation of wave loads on a moored floating structure, such as Spar or TLP (Tension Leg Platform), which can be approximated by a slender body or a number of slender components. Dr. Jun Zhang, with his former and current graduate students, have developed a numerical code, known as COUPLE, over the past two decades, simulating 6 Degree Of Freedom (DOF) motions of a moored floating structures interacting with waves, current and wind. COUPLE employs UHWM as a module for computing wave loads on a floating structure. However, when the duration of simulating the wave-structure interaction is long, say 3 hours (typically required by the offshore industry for extreme storm cases), the computation time of using UHWM increases significantly in comparisons with the counterpart based upon linear wave theory. This study is to develop a numerical scheme which may significantly reduce the CPU time in the use of UHWM and COUPLE. In simulating irregular (or random) waves following a JONSWAP spectrum of a given cut off frequency, the number of free wave components in general grows linearly with the increase of the simulation duration. The CPU time for using a linear spectral method to simulate irregular waves is roughly proportion to N2, where N is the number of free wave components used in simulating irregular waves, while that for using a nonlinear wave model, such as UHWM, it is roughly proportional to N3. Therefore, to reduce the CPU time, the total simulation duration is divided into a number of segments. However, due to the nature of Fast Fourier Transform (FFT), the connection between the two neighboring surface elevations segments is likely discontinuous. To avoid the discontinuity, an overlapped duration between the two neighboring segments is adopted. For demonstration, a free-wave spectrum is input to COUPLE for simulating the 6 DOF motions of a floating 5-MW wind turbine installed on an OC3 moored Spar and tensions in the mooring lines. It is shown that the CPU time for the above simulation for duration of 2048 seconds is reduced from more than16 hours when the irregular wave elevation and kinematics are calculated without dividing into segments to less than three hours when those are calculated by dividing into five segments.

Jia, Dongxing 1984-

2012-12-01T23:59:59.000Z

333

Conceptual adsorption models and open issues pertaining to performance assessment  

SciTech Connect

Recently several articles have been published that question the appropriateness of the distribution coefficient, Rd, concept to quantify radionuclide migration. Several distinct issues are raised by various critics. In this paper I provide some perspective on issues surrounding the modeling of nuclide retardation. The first section defines adsorption terminology and discusses various adsorption processes. The next section describes five commonly used adsorption conceptual models, specifically emphasizing what attributes that affect adsorption are explicitly accommodated in each model. I also review efforts to incorporate each adsorption model into performance assessment transport computer codes. The five adsorption conceptual models are (1) the constant Rd model, (2) the parametric Rd model, (3) isotherm adsorption models, (4) mass-action adsorption models, and (5) surface-complexation with electrostatics models. The final section discusses the adequacy of the distribution ratio concept, the adequacy of transport calculations that rely on constant retardation factors and the status of incorporating sophisticated adsorption models into transport codes.

Serne, R.J.

1991-10-01T23:59:59.000Z

334

A Numerical Examination of the Castro-Mahecha Supersymmetric Model of the Riemann Zeros  

E-Print Network (OSTI)

The unknown parameters of the recently-proposed (Int J. Geom. Meth. Mod. Phys. 1, 751 [2004]) Castro-Mahecha model of the imaginary parts (lambda_{j}) of the nontrivial Riemann zeros are the phases (alpha_{k}) and the frequency parameter (gamma) of the Weierstrass function of fractal dimension D=3/2 and the turning points (x_{j}) of the supersymmetric potential-squared Phi^2(x) -- which incorporates the smooth Wu-Sprung potential (Phys. Rev. E 48, 2595 [1993]), giving the average level density of the Riemann zeros. We conduct numerical investigations to estimate/determine these parameters -- as well as a parameter (sigma) we introduce to scale the fractal contribution. Our primary analyses involve two sets of coupled equations: one set being of the form Phi^{2}(x_{j}) = lambda_{j}, and the other set corresponding to the fractal extension -- according to an ansatz of Castro and Mahecha -- of the Comtet-Bandrauk-Campbell (CBC) quasi-classical quantization conditions for good supersymmetry. Our analyses suggest the possibility strongly that gamma converges to its theoretical lower bound of 1, and the possibility that all the phases (alpha_{k}) should be set to zero. We also uncover interesting formulas for certain fractal turning points.

Paul B. Slater

2005-11-07T23:59:59.000Z

335

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

DOE Green Energy (OSTI)

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

336

NUMERICAL MODELING OF THE INITIATION OF CORONAL MASS EJECTIONS IN ACTIVE REGION NOAA 9415  

SciTech Connect

Coronal mass ejections (CMEs) and solar flares are the main drivers of weather in space. Understanding how these events occur and what conditions might lead to eruptive events is of crucial importance for up to date and reliable space weather forecasting. The aim of this paper is to present a numerical magnetohydrodynamic (MHD) data-inspired model suitable for the simulation of the CME initiation and their early evolution. Starting from a potential magnetic field extrapolation of the active region (AR) NOAA 9415, we solve the full set of ideal MHD equations in a non-zero plasma-{beta} environment. As a consequence of the applied twisting motions, a force-free-magnetic field configuration is obtained, which has the same chirality as the investigated AR. We investigate the response of the solar corona when photospheric motions resembling the ones observed for AR 9415 are applied at the inner boundary. As a response to the converging shearing motions, a flux rope is formed that quickly propagates outward, carrying away the plasma confined inside the flux rope against the gravitational attraction by the Sun. Moreover, a compressed leading edge propagating at a speed of about 550 km s{sup -1} and preceding the CME is formed. The presented simulation shows that both the initial magnetic field configuration and the plasma-magnetic-field interaction are relevant for a more comprehensive understanding of the CME initiation and early evolution phenomenon.

Zuccarello, F. P.; Poedts, S. [Centre for Mathematical Plasma-Astrophysics, KU Leuven, Celestijnenlaan 200B, B-3001 Leuven (Belgium); Meliani, Z., E-mail: Francesco.Zuccarello@wis.kuleuven.be, E-mail: Stefaan.Poedts@wis.kuleuven.be, E-mail: zakaria.meliani@obspm.fr [Observatoire de Paris, LUTh, F-92190 Meudon (France)

2012-10-20T23:59:59.000Z

337

Models used to assess the performance of photovoltaic systems.  

DOE Green Energy (OSTI)

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

338

HAsim : cycle-accurate multicore performance models on FPGAs  

E-Print Network (OSTI)

The goal of this project is to improve computer architecture by accelerating cycle-accurate performance modeling of multicore processors using FPGAs. Contributions include a distributed technique controlling simulation on ...

Pellauer, Michael (Michael Ignatius)

2011-01-01T23:59:59.000Z

339

A performance model for fine-grain accesses in UPC  

Science Conference Proceedings (OSTI)

UPC's implicit communication and fine-grain programming style make application performance modeling a challenging task. The correspondence between remote references and communication events depends on the internals of the compiler and runtime system. ...

Zhang Zhang; Steven R. Seidel

2006-04-01T23:59:59.000Z

340

BatPaC - Battery Performance and Cost model - Home  

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

> BatPaC Home About BatPaC Download BatPaC Contact Us BatPaC: A Lithium-Ion Battery Performance and Cost Model for Electric-Drive Vehicles The recent penetration of...

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

Model-based performance instrumentation of distributed applications  

Science Conference Proceedings (OSTI)

Problems such as inconsistent or erroneous instrumentation often plague applications whose source code ismanually instrumented during the implementation phase. Integrating performance instrumentation capabilities into theModel Driven Software Development ...

Jan Schaefer; Jeanne Stynes; Reinhold Kroeger

2008-06-01T23:59:59.000Z

342

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

343

A Numerical Model for Evaluating the Impact of Noble Metal Chemical Addition in Boiling Water Reactors  

SciTech Connect

The technique of noble metal chemical addition (NMCA), accompanied by a low-level hydrogen water chemistry (HWC), is being employed by several U.S. nuclear power plants for mitigating intergranular stress corrosion cracking in the vessel internals of their boiling water reactors (BWRs). An improved computer model by the name of DEMACE was employed to evaluate the performance of NMCA throughout the primary coolant circuit (PCC) of a commercial BWR. The molar ratios of hydrogen to oxidizing species in the PCC under normal water chemistry and HWC are analyzed. The effectiveness of NMCA is justified by calculated electrochemical corrosion potential (ECP) around the PCC and in a local power range monitoring (LPRM) housing tube, in which practical in-vessel ECP measurements are normally taken.Prior to the modeling work for the BWR, the Mixed Potential Model, which is embedded in DEMACE and responsible for ECP calculation, was calibrated against both laboratory and plant ECP data. After modeling for various HWC conditions, it is found that the effectiveness of NMCA in the PCC of the selected BWR varies from region to region. In particular, the predicted ECP in the LPRM housing tube is notably different from that in the nearby bulk environment under NMCA, indicating that cautions must be given to a possible, undesirable outcome due to a distinct ECP difference between a locally confined area and the actual bulk environment.

Yeh, T.-K. [National Tsing-Hua University, Taiwan (China)

2002-10-15T23:59:59.000Z

344

Numerical Modeling of Reactive Multiphase Flow for FCC and Hot Gas Desulfurization Circulating Fluidized Beds  

Science Conference Proceedings (OSTI)

This work was carried out to understand the behavior of the solid and gas phases in a CFB riser. Only the riser is modeled as a straight pipe. A model with linear algebraic approximation to solids viscosity of the form, {musubs} = 5.34{epsisubs}, ({espisubs} is the solids volume fraction) with an appropriate boundary condition at the wall obtained by approximate momentum balance solution at the wall to acount for the solids recirculation is tested against experimental results. The work done was to predict the flow patterns in the CFB risers from available experimental data, including data from a 7.5-cm-ID CFB riser at the Illinois Institute of Technology and data from a 20.0-cm-ID CFB riser at the Particulate Solid Research, Inc., facility. This research aims at modeling the removal of hydrogen sulfide from hot coal gas using zinc oxide as the sorbent in a circulating fluidized bed and in the process indentifying the parameters that affect the performance of the sulfidation reactor. Two different gas-solid reaction models, the unreacted shrinking core (USC) and the grain model were applied to take into account chemical reaction resistances. Also two different approaches were used to affect the hydrodynamics of the process streams. The first model takes into account the effect of micro-scale particle clustering by adjusting the gas-particle drag law and the second one assumes a turbulent core with pseudo-steady state boundary condition at the wall. A comparison is made with experimental results.

None

2005-07-01T23:59:59.000Z

345

Evaluation of Blade-Strike Models for Estimating the Biological Performance of Large Kaplan Hydro Turbines  

DOE Green Energy (OSTI)

BioIndex testing of hydro-turbines is sought as an analog to the hydraulic index testing conducted on hydro-turbines to optimize their power production efficiency. In BioIndex testing the goal is to identify those operations within the range identified by Index testing where the survival of fish passing through the turbine is maximized. BioIndex testing includes the immediate tailrace region as well as the turbine environment between a turbine's intake trashracks and the exit of its draft tube. The US Army Corps of Engineers and the Department of Energy have been evaluating a variety of means, such as numerical and physical turbine models, to investigate the quality of flow through a hydro-turbine and other aspects of the turbine environment that determine its safety for fish. The goal is to use these tools to develop hypotheses identifying turbine operations and predictions of their biological performance that can be tested at prototype scales. Acceptance of hypotheses would be the means for validation of new operating rules for the turbine tested that would be in place when fish were passing through the turbines. The overall goal of this project is to evaluate the performance of numerical blade strike models as a tool to aid development of testable hypotheses for bioIndexing. Evaluation of the performance of numerical blade strike models is accomplished by comparing predictions of fish mortality resulting from strike by turbine runner blades with observations made using live test fish at mainstem Columbia River Dams and with other predictions of blade strike made using observations of beads passing through a 1:25 scale physical turbine model.

Deng, Zhiqun; Carlson, Thomas J.; Ploskey, Gene R.; Richmond, Marshall C.

2005-11-30T23:59:59.000Z

346

Comparison of Predictive Models for Photovoltaic Module Performance: Preprint  

DOE Green Energy (OSTI)

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

347

Performance potential for simulating spin models on GPU  

Science Conference Proceedings (OSTI)

Graphics processing units (GPUs) are recently being used to an increasing degree for general computational purposes. This development is motivated by their theoretical peak performance, which significantly exceeds that of broadly available CPUs. For ... Keywords: Graphics processing units, Heisenberg model, Ising model, Monte Carlo simulations, Parallel tempering, Spin glasses

Martin Weigel

2012-04-01T23:59:59.000Z

348

Numerical modelling of dynamical interaction between seismic radiation and near-surface geological structures: a parallel approach  

Science Conference Proceedings (OSTI)

We investigate a faster and easier way to parallelise seismological codes able to simulate the dynamical interaction between seismic radiation and near-surface geological structures. This is important in assessing strong ground motion, in the mitigation ... Keywords: HPF, numerical modelling, openMP, parallel computing, seismic site effects

A. Caserta; V. Ruggiero; P. Lanucara

2002-11-01T23:59:59.000Z

349

Numerical identification of parameters for a strongly degenerate convection--diffusion problem modelling centrifugation of flocculated suspensions  

Science Conference Proceedings (OSTI)

This paper presents the identification of parameters in the flux and diffusion functions for a quasilinear strongly degenerate parabolic equation which models the centrifugation of flocculated suspensions. We consider both a rotating tube and a basket ... Keywords: Degenerate parabolic differential equation, Inverse problem, Numerical methods

S. Berres; R. Bürger; A. Coronel; M. Sepúlveda

2005-03-01T23:59:59.000Z

350

The Numerical Solution of the Mellor-Yamada Level 2.5 Turbulent Kinetic Energy Equation in the Eta Model  

Science Conference Proceedings (OSTI)

A new method is presented for obtaining the numerical solution of the production-dissipation component of the turbulent kinetic energy equation that arises in the Mellor-Yamada level 2.5 turbulent closure model. The development of this new method ...

Joseph P. Gerrity Jr.; Thomas L. Black; Russell E. Treadon

1994-07-01T23:59:59.000Z

351

A Numerical Study of Breaking Kelvin-Helmholtz Billows using a Reynolds-Stress Turbulence Closure Model  

Science Conference Proceedings (OSTI)

A two-dimensional numerical study of breaking Kelvin-Helmholtz billows is presented. The turbulent breaking process is modeled using second-order closure methods to describe the small-wale turbulence, while the large-scale billow itself is ...

R. I. Sykes; W. S. Lewellen

1982-07-01T23:59:59.000Z

352

Numerical methods for instability mitigation in the modeling of laser wakefield accelerators in a Lorentz-boosted frame  

Science Conference Proceedings (OSTI)

Modeling of laser-plasma wakefield accelerators in an optimal frame of reference [1] has been shown to produce orders of magnitude speed-up of calculations from first principles. Obtaining these speedups required mitigation of a high-frequency instability ... Keywords: Boosted frame, Laser wakefield acceleration, Numerical instability, Particle-in-cell, Plasma simulation, Special relativity

J. -L. Vay; C. G. R. Geddes; E. Cormier-Michel; D. P. Grote

2011-07-01T23:59:59.000Z

353

A Local Minimum Aliasing Method for Use in Nonlinear Numerical Models  

Science Conference Proceedings (OSTI)

The local spectral method is a minimum aliasing technique for the discretization and numerical integration of prognostic systems consisting of nonlinear partial differential equations. The technique embodies many features of both spectral ...

John R. Anderson

1989-07-01T23:59:59.000Z

354

The Fleet Numerical Oceanography Center Suite of Oceanographic Models and Products  

Science Conference Proceedings (OSTI)

Fleet Numerical Oceanography Center (FLENUMOCEANCEN) is the navy's real-time prediction center for global-scale and open-ocean regional-scale oceanographic products, having filled this role for over 25 years. FLENUMOCEANCEN provides operational ...

R. M. Clancy; LCDR W. D. Sadler

1992-06-01T23:59:59.000Z

355

Transient heat transfer through walls and thermal bridges. numerical modelling: methodology and validation  

Science Conference Proceedings (OSTI)

The current advanced numerical codes for the energy audits carry out 0-dimensional simulation (i.e., one computational node representing the thermal zone), underestimating the effects of thermal bridges on the seasonal heating demand of buildings. The ...

Fabrizio Ascione; Filippo de' Rossi; Nicola Bianco; Giuseppe Peter Vanoli

2012-12-01T23:59:59.000Z

356

Three-Dimensional Numerical Model Simulations of Airflow Over Mountainous Terrain: A Comparison with Observations  

Science Conference Proceedings (OSTI)

Numerical simulations of airflow over two different choices of mountainous terrain and the comparisons of results with aircraft observations are presented. Two wintertime casts for flow over Elk Mountain, Wyoming where surface heating is assumed ...

Terry L. Clark; Robert Gall

1982-07-01T23:59:59.000Z

357

Coupling between Sea Surface Temperature and Low-Level Winds in Mesoscale Numerical Models  

Science Conference Proceedings (OSTI)

This study evaluates the impacts of sea surface temperature (SST) specification and grid resolution on numerical simulations of air–sea coupling near oceanic fronts through analyses of surface winds from the European Centre for Medium-Range ...

Qingtao Song; Dudley B. Chelton; Steven K. Esbensen; Nicolai Thum; Larry W. O’Neill

2009-01-01T23:59:59.000Z

358

Real &me numerical forecast of global epidemic spreading using large-scale computa&onal models  

E-Print Network (OSTI)

Real &me numerical forecast of global epidemic spreading using large conditions). Forecast = best prediction given the present knowledge on the system. Projection = attempt functionalities) #12;Real time forecast for the H1N1pdm (2009) Key parameters

Cattuto, Ciro

359

Direct Numerical Simulations of a Smoke Cloud–Top Mixing Layer as a Model for Stratocumuli  

Science Conference Proceedings (OSTI)

A radiatively driven cloud-top mixing layer is investigated using direct numerical simulations. This configuration mimics the mixing process across the inversion that bounds the stratocumulus-topped boundary layer. The main focus of this paper is ...

Alberto de Lozar; Juan Pedro Mellado

2013-08-01T23:59:59.000Z

360

A Numerical Modeling Study of the Upwelling Source Waters along the Oregon Coast during 2005  

Science Conference Proceedings (OSTI)

Regional ocean circulation along the Oregon coast is studied numerically for forcing fields derived from year 2005 and climatological-mean conditions. The primary object is to study directly the Lagrangian pathways by which fluid arrives in the ...

David Rivas; R. M. Samelson

2011-01-01T23:59:59.000Z

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.


361

The Formation of Comma Vortices in a Tropical Numerical Simulation Model  

Science Conference Proceedings (OSTI)

A detailed analysis of a numerically simulated tropical disturbance displays a comma-shaped pattern at the mature stage in the low-level vorticity, surface convergence, mid-level upward motion and precipitation fields.

Robert E. Tuleya; Yoshio Kurihara

1984-03-01T23:59:59.000Z

362

Diagnosis and Correction of Systematic Humidity Error in a Global Numerical Weather Prediction Model  

Science Conference Proceedings (OSTI)

Accuracy of humidity forecasts has been considered relatively unimportant to much of the operational numerical weather prediction (NWP) community. However, the U.S. Air Force is interested in accurate water vapor and cloud forecasts as end ...

Donald C. Norquist; Sam S. Chang

1994-11-01T23:59:59.000Z

363

Extending the Numerical Stability Limit of Terrain-Following Coordinate Models over Steep Slopes  

Science Conference Proceedings (OSTI)

To extend the numerical stability limit over steep slopes, a truly horizontal pressure-gradient discretization based on the ideas formulated by Mahrer in the 1980s has been developed. Conventionally, the pressure gradient is evaluated in the ...

Günther Zängl

2012-11-01T23:59:59.000Z

364

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

E-Print Network (OSTI)

Nonlinear coupling problems between the multiple bodies or between the mooring/riser and the offshore platform are incorporated in the CHARM3D-MultiBody, a fully coupled time domain analysis program for multiple bodies with moorings and risers. The nonlinear spring connection module and the three dimensional beam module are added to appropriately solve the structural connection problem. The nonlinear spring connection module includes the hydro-pneumatic tensioner module with the friction & stick/slip implementation, the tendon/mooring disconnection (breakage/unlatch) module with the tendon down-stroke check, and the contact spring with the initial gap with the friction force implemented. The nonlinear coupling may happen in many places for the offshore floating structures, such as hydro-pneumatic tensioner, tendon of TLP down stroke at the bottom joint, stick-slip phenomena at the tie down of the derrick and most of the fender-to-steel or steel-to-steel contact problem with initial gap during the installation. The mooring/tendon broken and unlatch can be a nonlinear connection problem once the transient mode is taken into account. Nonlinearity of the stiffness and friction characteristics of the tensioner combined with stick-slip behavior of riser keel joint is investigated. The relationship between tensions and strokes for hydro-pneumatic tensioner is based on the ideal gas equation where the isotropic gas constant can be varied to achieve an optimum stroke design based on tensioner stiffness. A transient effect of tendon down-stroke and disconnection on global performance of ETLP for harsh environmental condition is also investigated by incorporating the nonlinear boundary condition of the FE tendon model in CHARM3D. The program is made to be capable of modeling the tendon disconnection both at the top and the bottom connection as well as the down stroke behavior for the pinned bottom joint. The performance of the tie-down clamp of derrick is also investigated by using six degrees of freedom 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 or FE beam model. The method reduces too much conservatism when we design the tie-down system by the conventional method, in which all the environmental forces are combined without the phase lag effect between them. The FE beam model is also applied to the connectors between the semisubmersible and the truss for the pre-service and in-place conditions to be verified with the model test results, which shows good agreements.

Yang, Chan K.

2009-05-01T23:59:59.000Z

365

Human performance modeling for system of systems analytics.  

Science Conference Proceedings (OSTI)

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

366

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.

367

A Linear Parabolic Trough Solar Collector Performance Model  

E-Print Network (OSTI)

A performance model has been programmed for solar thermal collector based on a linear, tracking parabolic trough reflector focused on a surface-treated metallic pipe receiver enclosed in an evacuated transparent tube: a Parabolic Trough Solar Collector (PTSC). This steady state, single dimensional model comprises the fundamental radiative and convective heat transfer and mass and energy balance relations programmed in the Engineering Equation Solver, EES. It considers the effects of solar intensity and incident angle, collector dimensions, material properties, fluid properties, ambient conditions, and operating conditions on the performance of the collector: the PTSC. Typical performance calculations show that when hot-water at 165C flows through a 6m by 2.3m PTSC with 900 w/m^2 solar insulation and 0 incident angle, the estimated collector efficiency is about 55% The model predictions will be confirmed by the operation of PTSCs now being installed at Carnegie Mellon.

Qu, M.; Archer, D.; Masson, S.

2006-01-01T23:59:59.000Z

368

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

369

Numerical Modeling of Cased-hole Instability in High Pressure and High Temperature Wells  

E-Print Network (OSTI)

Down-hole damages such as borehole collapse, circulation loss and rock tensile/compressive cracking in the open-hole system are well understood at drilling and well completion stages. However, less effort has been made to understand the instability of cemented sections in High Pressure High Temperature (HPHT) wells. The existing analysis shows that, in the perforation zones, casing/cement is subject to instability, particularly in the presence of cavities. This dissertation focuses on the instability mechanism of casing/cement in the non-perforated zones. We investigate the transient thermal behavior in the casing-cement-formation system resulting from the movement of wellbore fluid using finite element method. The critical value of down-hole stresses is identified in both wellbore heating and cooling effects. Differently with the heating effect, the strong cooling effect in a cased hole can produce significant tension inside casing/cement. The confining formation has an obvious influence on the stability of casing/cement. The proposed results reveal that the casing/cement system in the non-homogeneous formation behaves differently from that in homogeneous formation. With this in mind, a three-dimensional layered finite element model is developed to illustrate the casing/cement mechanical behavior in the non-homogeneous formation. The radial stress of cement sheath is found to be highly variable and affected by the contrast in Young’s moduli in the different formation layers. The maximum stress is predicted to concentrate in the casing-cement system confined by the sandstone. Casing wear in the cased-hole system causes significant casing strength reduction, possibly resulting in the casing-cement tangential collapse. In this study, an approach for calculating the stress concentration in the worn casing with considering temperature change is developed, based on boundary superposition. The numerical results indicate that the casing-cement system after casing wear will suffer from severe tangential instability due to the elevated compressive hoop stress. Gas migration during the cementing process results from the fluid cement’s inability to balance formation pore pressure. Past experience emphasized the application of chemical additives to reduce or control gas migration during the cementing process. This report presents the thermal and mechanical behaviors in a cased hole caused by created gas channels after gas migration. In conclusion, the size and the number of gas channels are two important factors in determining mechanical instability in a casing-cement system.

Shen, Zheng 1983-

2012-12-01T23:59:59.000Z

370

Current Capability of Operational Numerical Models in Predicting Tropical Cyclone Intensity in the Western North Pacific  

Science Conference Proceedings (OSTI)

Forecasts of tropical cyclone (TC) intensity from six operational models (three global models and three regional models) during 2010 and 2011 are assessed to study the current capability of model guidance in the western North Pacific. The ...

Hui Yu; Peiyan Chen; Qingqing Li; Bi Tang

2013-04-01T23:59:59.000Z

371

Hybrid Model for Building Performance Diagnosis and Optimal Control  

E-Print Network (OSTI)

Modern buildings require continuous performance monitoring, automatic diagnostics and optimal supervisory control. For these applications, simplified dynamic building models are needed to predict the cooling and heating requirement viewing the building as a whole system. This paper proposes a new hybrid model. Half of the model is represented by detailed physical parameters and another half is described by identified parameters. 3R2C thermal network model, which consists of three resistances 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 of three resistances and two capacitances. The resistances and capacitances of the 2R2C model are assumed to be constant. A GA (genetic algorithm)-based method is developed for model parameter identification by searching the optimal parameters of 3R2C models of envelopes in frequency domain and that of the 2R2C model of the building internal mass in time domain. As the model is based on the physical characteristics, the hybrid model can be used to predict the cooling and heating energy consumption of buildings accurately in wide range of operation conditions.

Wang, S.; Xu, X.

2003-01-01T23:59:59.000Z

372

Thermal radiant exitance model performance: Soils and forests  

DOE Green Energy (OSTI)

Models of surface temperatures of two land surface types based on their energy budgets were developed to simulate the effects of environmental factors on thermal radiant exitance. The performance of these models is examined in detail. One model solves the non-linear differential equation for heat diffusion in solids using a set of submodels for surface energy budget components. The model performance is examined under three desert conditions thought to be a strong test of the submodels. The accuracy of the temperature predictions and submodels is described. The accuracy of the model is generally good but some discrepancies between some of the submodels and measurements are noted. The sensitivity of the submodels is examined and is seen to be strongly controlled by interaction and feedback among energy components that are a function of surface temperature. The second model simulates vegetation canopies with detailed effects of surface geometry on radiant transfer in the canopy. Foliage solar absorption coefficients are calculated using a radiosity approach for a three layer canopy and long wave fluxes are modeled using a view factor matrix. Sensible and latent heat transfer through the canopy are also simulated using, nearby meteorological data but heat storage in the canopy is not included. Simulations for a coniferous forest canopy are presented and the sensitivity of the model to environmental inputs is discussed.

Balick, L.K. [EG& G Energy Measurements Inc., Las Vegas, NV (United States); Smith, J.A. [NASA/Goddard Space Flight Center, Greenbelt, MD (United States). Lab. for Terrestrial Physics

1995-12-31T23:59:59.000Z

373

Tidal Exchange through a Strait: A Numerical Experiment Using a Simple Model Basin  

Science Conference Proceedings (OSTI)

In order to investigate the mechanism of tidal exchange through a strait, we numerically track the Lagrangian movement of water particles over a full cycle of the M2 tide. As a result, it is found that the spatially rapid changes of the amplitude ...

Toshiyuki Awaji; Norihisa Imasato; Hideaki Kunishi

1980-10-01T23:59:59.000Z

374

Penetration of solar radiation in the upper ocean: A numerical model for oceanic and coastal waters  

E-Print Network (OSTI)

or measurements made from space [Gregg and Carder, 1990; Mueller et al., 2004]. This energy can be considered as two separate portions: energy with wavelengths less than 700 nm (visible domain, EVIS), and energy values of a and bb as inputs. To reach this goal, we carried out extensive numerical simulations by Hydro

Lee, Zhongping

375

High-performance land surface modeling with a Linux cluster  

Science Conference Proceedings (OSTI)

The Land Information System (LIS) was developed at NASA to perform global land surface simulations at a resolution of 1-km or finer in real time. Such unprecedented scales and intensity pose many computational challenges. In this article, we demonstrate ... Keywords: Beowulf cluster, Distributed computing, High-resolution simulation, Hydrology modeling, Parallel computing, Peer-to-peer network

Y. Tian; C. D. Peters-Lidard; S. V. Kumar; J. Geiger; P. R. Houser; J. L. Eastman; P. Dirmeyer; B. Doty; J. Adams

2008-11-01T23:59:59.000Z

376

Performance modelling of a network processor using POOSL  

Science Conference Proceedings (OSTI)

The increasing complexity of innovative real-time hardware/software systems forced industry to consider system-level design methods. Before actually implementing a system with hardware and software components, system-level design methods enable analysing ... Keywords: concurrency, formal description techniques, network processor, parallel object-oriented specification language, performance modelling, system-level design

B. D. Theelen; J. P. M. Voeten; R. D. J. Kramer

2003-04-01T23:59:59.000Z

377

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

378

Examination of Numerical Results from Tangent Linear and Adjoint of Discontinuous Nonlinear Models  

Science Conference Proceedings (OSTI)

The forward model solution and its functional (e.g., the cost function in 4DVAR) are discontinuous with respect to the model's control variables if the model contains discontinuous physical processes that occur during the assimilation window. In ...

S. Zhang; X. Zou; Jon E. Ahlquist

2001-11-01T23:59:59.000Z

379

Three-Dimensional Numerical Modeling of Convection Produced by Interacting Thunderstorm Outflows. Part I: Control Simulation and Low-Level Moisture Variations  

Science Conference Proceedings (OSTI)

The Klemp–Wilhelmson three-dimensional numerical cloud model is used to investigate cloud development along intersecting thunderstorm outflow boundaries. The model initial environment is characterized by a temperature and moisture profile ...

Kelvin K. Droegemeier; Robert B. Wilhelmson

1985-11-01T23:59:59.000Z

380

Numerical study on transient heat transfer under soil with plastic mulch in agriculture applications using a nonlinear finite element model  

E-Print Network (OSTI)

In this paper is developed a simple mathematical model of transient heat transfer under soil with plastic mulch in order to determine with numerical studies the influence of different plastic mulches on the soil temperature and the evolutions of temperatures at different depths with time. The governing differential equations are solved by a Galerkin Finite Element Model, taking into account the nonlinearities due to radiative heat exchange between the soil surface, the plastic mulch and the atmosphere. The model was validated experimentally giving good approximation of the model to the measured data. Simulations were run with the validated model in order to determine the optimal combination of mulch optical properties to maximize the soil temperature with a Taguchi's analysis, proving that the material most used nowadays in Colombia is not the optimal and giving quantitative results of the properties the optimal mulch must possess.

De Castro, Carlos Armando

2011-01-01T23:59:59.000Z

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

An improved numerical model for the investigation of thermal hydraulic phenomena with applications to LMR reactor components  

SciTech Connect

A basic limited scope, fast-running computer model is presented for the solution of single phase two-dimensional transients in thermally coupled incompressible fluid flow problems. The governing equations and the two-equation transport model (k-{epsilon}) of turbulence are reduced to a set of linear algebraic equations in an implicit finite difference scheme, based on the control volume approach. These equations are solved iteratively in a line-by-line procedure using the tri-diagonal matrix algorithm. The numerical formulation and general calculational procedure are described in detail. The calculations show good agreement when compared with experimental data and other independent analyses.

Chan, B.C.; Kennett, R.J.; Van Tuyle, G.J.

1992-01-01T23:59:59.000Z

382

An improved numerical model for the investigation of thermal hydraulic phenomena with applications to LMR reactor components  

SciTech Connect

A basic limited scope, fast-running computer model is presented for the solution of single phase two-dimensional transients in thermally coupled incompressible fluid flow problems. The governing equations and the two-equation transport model (k-{epsilon}) of turbulence are reduced to a set of linear algebraic equations in an implicit finite difference scheme, based on the control volume approach. These equations are solved iteratively in a line-by-line procedure using the tri-diagonal matrix algorithm. The numerical formulation and general calculational procedure are described in detail. The calculations show good agreement when compared with experimental data and other independent analyses.

Chan, B.C.; Kennett, R.J.; Van Tuyle, G.J.

1992-08-01T23:59:59.000Z

383

Learning uncertainty models from weather forecast performance databases using quantile regression  

Science Conference Proceedings (OSTI)

Forecast uncertainty information is not available in the immediate output of Numerical weather prediction (NWP) models. Such important information is required for optimal decision making processes in many domains. Prediction intervals are a prominent ... Keywords: numerical weather forecast, prediction interval, quantile regression, uncertainty modeling

Ashkan Zarnani; Petr Musilek

2013-07-01T23:59:59.000Z

384

Shape Optimization for Navier-Stokes Equations with Algebraic Turbulence Model: Numerical Analysis and Computation  

SciTech Connect

We study the shape optimization problem for the paper machine headbox which distributes a mixture of water and wood fibers in the paper making process. The aim is to find a shape which a priori ensures the given velocity profile on the outlet part. The mathematical formulation leads to the optimal control problem in which the control variable is the shape of the domain representing the header, the state problem is represented by the generalized Navier-Stokes system with nontrivial boundary conditions. This paper deals with numerical aspects of the problem.

Haslinger, Jaroslav, E-mail: hasling@karlin.mff.cuni.cz [Charles University, Department of Numerical Mathematics, Faculty of Mathematics and Physics (Czech Republic); Stebel, Jan, E-mail: stebel@math.cas.cz [Academy of Sciences of the Czech Republic, Institute of Mathematics (Czech Republic)

2011-04-15T23:59:59.000Z

385

Numerical Model Studies of the Winter-Storm Response of the West Florida Shelf  

Science Conference Proceedings (OSTI)

The wintertime, wind-driven Ocean circulation on the West Florida Continental Shelf is studied within the framework of a linearized storm-surge model. The model bathymetry incorporates a realistic shelf, extending from New Orleans to the southern ...

Ya Hsueh; G. O. Marmorino; Linda L. Vansant

1982-10-01T23:59:59.000Z

386

Ensemble Data Assimilation to Characterize Surface-Layer Errors in Numerical Weather Prediction Models  

Science Conference Proceedings (OSTI)

Experiments with the single-column implementation of the Weather Research and Forecasting Model provide a basis for deducing land–atmosphere coupling errors in the model. Coupling occurs both through heat and moisture fluxes through the land–...

J. P. Hacker; W. M. Angevine

2013-06-01T23:59:59.000Z

387

Toward a Dynamic-Thermodynamic Assimilation of Satellite Surface Temperature in Numerical Atmospheric Models  

Science Conference Proceedings (OSTI)

An assimilation technique is described in which satellite-observed surface skin temperature tendencies are used in a model surface energy budget so that the predicted rate of temperature change in the model more closely agrees with the satellite ...

Richard T. McNider; Aaron J. Song; Daniel M. Casey; Peter J. Wetzel; William L. Crosson; Robert M. Rabin

1994-12-01T23:59:59.000Z

388

Numerical Prediction of Convectively Driven Mesoscale Pressure Systems. Part II. Mesoscale Model  

Science Conference Proceedings (OSTI)

A 20-level, three-dimensional, primitive equation model with 20 km horizontal resolution is used to predict the development of convectively driven mesoscale pressure systems. Systems produced by the model have life histories and structural ...

J. M. Fritsch; C. F. Chappell

1980-08-01T23:59:59.000Z

389

Numerical Simulation of a Buoyant Thermal Using the k-? Turbulence Model  

Science Conference Proceedings (OSTI)

Possibilities for describing turbulent mixing processes through the use of the two-equation k-? model modified to take into account the effects of streamline curvature and buoyancy are discussed. It is shown that one of the k-? model constants ...

Y. A. Dovgalyuk; M. A. Zatevakhin; E. N. Stankova

1994-09-01T23:59:59.000Z

390

A Numerical Study of Climatic Oscillations Using a Coupled Atmosphere–Ocean Primitive Equation Model  

Science Conference Proceedings (OSTI)

A coupled atmosphere-ocean primitive equation model is developed. It is a free-dimensional general circulation model, with two layers in the atmosphere and two layers in the ocean and includes solar radiation, longwave radiation, sensible heating,...

Xiong-Shan Chen

1984-03-01T23:59:59.000Z

391

Numerical Simulation of ANATEX Tracer Data Using a Turbulence Closure Model for Long-Range Dispersion  

Science Conference Proceedings (OSTI)

A long-range transport model based on turbulence closure concepts is described. The model extends the description of planetary boundary layer turbulent diffusion to the larger scales and uses statistical wind information to predict contaminant ...

R. I. Sykes; S. F. Parker; D. S. Henn; W. S. Lewellen

1993-05-01T23:59:59.000Z

392

3-D numerical modelling of coastal currents and suspended sediment transport  

Science Conference Proceedings (OSTI)

A three dimensional hydrodynamic and suspended sediment transport model (HYDROTAM-3) has been developed and applied to Fethiye Bay. Model can simulate the transport processes due to tidal or nontidal forcing which may be barotropic or baroclinic. The ...

Lale Balas; Alp Küçükosmano?lu; Umut Yegül

2006-05-01T23:59:59.000Z

393

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

Science Conference Proceedings (OSTI)

Computational models based on discrete dynamical equations are a successful way of approaching the problem of predicting or forecasting the future evolution of dynamical systems. For linear and mildly nonlinear models, the solutions of the ...

João Teixeira; Carolyn A. Reynolds; Kevin Judd

2007-01-01T23:59:59.000Z

394

African Easterly Wave Dynamics in a Mesoscale Numerical Model: The Upscale Role of Convection  

Science Conference Proceedings (OSTI)

To examine the dynamical role of convection in African easterly wave (AEW) life cycles the Weather Research and Forecasting (WRF) model is used to simulate the evolution of a single AEW from September 2004. The model simulations are validated ...

Gareth J. Berry; Chris D. Thorncroft

2012-04-01T23:59:59.000Z

395

Interannual Variability of Meridional Heat Transport in a Numerical Model of the Upper Equatorial Pacific ocean  

Science Conference Proceedings (OSTI)

The interannual heat budget of the Pacific equatorial upwelling zone is studied using a primitive equation, a reduced gravity model of the upper Pacific equatorial ocean. The model is forced with monthly mean FSU winds from 1971 to 1990. A ...

Esther C. Brady

1994-12-01T23:59:59.000Z

396

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

397

Motion and Evolution of Binary Tropical Cyclones in a Coupled Atmosphere–Ocean Numerical Model  

Science Conference Proceedings (OSTI)

The interaction of binary tropical cyclones (TC) is investigated using a coupled TC-ocean movable nested-grid model. The model consists of an eight-layer atmospheric model in the sigma coordinate system and a three-layer primitive equation ocean ...

Alexander I. Falkovich; Alexander P. Khain; Isaac Ginis

1995-05-01T23:59:59.000Z

398

Duct thermal performance models for large commercial buildings  

SciTech Connect

Despite the potential for significant energy savings by reducing duct leakage or other thermal losses from duct systems in large commercial buildings, California Title 24 has no provisions to credit energy-efficient duct systems in these buildings. A substantial reason is the lack of readily available simulation tools to demonstrate the energy-saving benefits associated with efficient duct systems in large commercial buildings. The overall goal of the Efficient Distribution Systems (EDS) project within the PIER High Performance Commercial Building Systems Program is to bridge the gaps in current duct thermal performance modeling capabilities, and to expand our understanding of duct thermal performance in California large commercial buildings. As steps toward this goal, our strategy in the EDS project involves two parts: (1) developing a whole-building energy simulation approach for analyzing duct thermal performance in large commercial buildings, and (2) using the tool to identify the energy impacts of duct leakage in California large commercial buildings, in support of future recommendations to address duct performance in the Title 24 Energy Efficiency Standards for Nonresidential Buildings. The specific technical objectives for the EDS project were to: (1) Identify a near-term whole-building energy simulation approach that can be used in the impacts analysis task of this project (see Objective 3), with little or no modification. A secondary objective is to recommend how to proceed with long-term development of an improved compliance tool for Title 24 that addresses duct thermal performance. (2) Develop an Alternative Calculation Method (ACM) change proposal to include a new metric for thermal distribution system efficiency in the reporting requirements for the 2005 Title 24 Standards. The metric will facilitate future comparisons of different system types using a common ''yardstick''. (3) Using the selected near-term simulation approach, assess the impacts of duct system improvements in California large commercial buildings, over a range of building vintages and climates. This assessment will provide a solid foundation for future efforts that address the energy efficiency of large commercial duct systems in Title 24. This report describes our work to address Objective 1, which includes a review of past modeling efforts related to duct thermal performance, and recommends near- and long-term modeling approaches for analyzing duct thermal performance in large commercial buildings.

Wray, Craig P.

2003-10-01T23:59:59.000Z

399

MODELING THE PERFORMANCE OF HIGH BURNUP THORIA AND URANIA PWR FUEL  

E-Print Network (OSTI)

Fuel performance models have been developed to assess the performance of ThO[subscript 2]-UO[subscript 2]

Long, Y.

400

Design and Analysis of Numerical Experiments  

Science Conference Proceedings (OSTI)

Calculations with numerical models are often referred to as numerical experiments, by analogy to classical laboratory experiments. Usually, many numerical experiments are carried out to determine the response of a numerical model to variations of ...

Kenneth P. Bowman; Jerome Sacks; Yue-Fang Chang

1993-05-01T23:59:59.000Z

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.


401

Modeling Windows in Energy Plus with Simple Performance Indices  

Science Conference Proceedings (OSTI)

The building energy simulation program, Energy Plus (E+), cannot use standard window performance indices (U, SHGC, VT) to model window energy impacts. Rather, E+ uses more accurate methods which require a physical description of the window. E+ needs to be able to accept U and SHGC indices as window descriptors because, often, these are all that is known about a window and because building codes, standards, and voluntary programs are developed using these terms. This paper outlines a procedure, developed for E+, which will allow it to use standard window performance indices to model window energy impacts. In this 'Block' model, a given U, SHGC, VT are mapped to the properties of a fictitious 'layer' in E+. For thermal conductance calculations, the 'Block' functions as a single solid layer. For solar optical calculations, the model begins by defining a solar transmittance (Ts) at normal incidence based on the SHGC. For properties at non-normal incidence angles, the 'Block' takes on the angular properties of multiple glazing layers; the number and type of layers defined by the U and SHGC. While this procedure is specific to E+, parts of it may have applicability to other window/building simulation programs.

Arasteh, Dariush; Kohler, Christian; Griffith, Brent

2009-10-12T23:59:59.000Z

402

Numerical modeling of gas migration into and through faulted sand reservoirs in Pabst Field (Main Pass East Block 259), northern Gulf of Mexico  

E-Print Network (OSTI)

The further exploration and development of Pabst Gas Field with faulted sand reservoirs require an understanding of the properties and roles of faults, particularly Low Throw near Vertical Faults (LTNVFs), in gas migration and accumulation at a reservoir scale. This study presents numerical modeling of gas migration and accumulation processes in Pabst Field. Based on studies of the reservoirs, structure, faults, and fluid properties of the field, reservoir scale modeling was performed to determine the gas supply style and the fault properties by means of hundreds of iterations in which the fault properties and gas supply pattern were modified to match the gas distribution obtained from modeling with the gas distribution inferred from seismic data constrained by well data and production data. This study finds that in the main three sand reservoirs of Pabst Field the overlying younger sands cut down into the underlying older sands, so that partial connections between the three sands allow gas communication among the sands. Meanwhile, three fault families break up the three sands into numerous compartments. A primary fault and large synthetic and antithetic faults act as gas migration pathways: the synthetic and antithetic faults are inlets for gas flow and the primary fault is an outlet, and LTNVFs act as barriers to gas flow. Modeling requires fault properties in the field to change while the field is formed. The porosity and permeability of the faults in Pabst Field are 10% and 0.1 md, respectively, during gas charging of the sand reservoirs. But when there is no gas charging and large gas columns are maintained, the porosity and permeability of the faults decrease to 6% and 0.001 md, respectively. Pabst Field probably has an impulse gas charge history. Fault opening and closing, gas charge and recharge, and replacement of gas by formation water may occur. A combination of stratigraphy, structure, overpressure and gas charge rate control gas migration style, gas charge history, and gas distribution in the field. The significance of the study is that this improved numerical approach for modeling gas migration into and through specifically faulted sand reservoirs fills the gap between basin modeling and production modeling.

Li, Yuqian

2005-05-01T23:59:59.000Z

403

Proceedings of the workshop on numerical modeling of thermohydrological flow in fractured rock masses  

DOE Green Energy (OSTI)

Nineteen papers were presented at the workshop on modeling thermohydrologic flow in fractured masses. This workshop was a result of the interest currently being given to the isolation of nuclear wastes in geologic formations. Included in these proceedings are eighteen of the presentations, one abstract and summaries of the panel discussions. The papers are listed under the following categories: introduction; overviews; fracture modelings; repository studies; geothermal models; and recent developments. Eighteen of the papers have been abstracted and indexed.

Not Available

1980-09-01T23:59:59.000Z

404

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

E-Print Network (OSTI)

thermal calculations for the WIPP site in southeastern NewWaste Isolation Pilot Plant (WIPP) in bedded salt. The codepersonal communication 1980). WIPP The modeling for WIPP is

Wang, J.S.Y.

2013-01-01T23:59:59.000Z

405

Efficient Schemes for Reducing Numerical Dispersion in Modeling Multiphase Transport through Porous and Fractured Media  

E-Print Network (OSTI)

within a fluid in a multiphase- porous-medium system isand radiation in a multiphase, multicomponent, porous mediumModeling Multiphase Transport through Porous and Fractured

Wu, Yu-Shu; Forsyth, Peter A.

2006-01-01T23:59:59.000Z

406

A physically based numerical approach for modeling fracture-matrix interaction in fractured reservoirs  

E-Print Network (OSTI)

in modeling multiphase flow in porous and fractured media,multiphase tracer transport in heterogeneous fractured porousof multiphase flow through fractured or porous media. 3.

Wu, Yu-Shu; Pruess, Karsten

2004-01-01T23:59:59.000Z

407

A physically based numerical approach for modeling fracture-matrix interaction in fractured reservoirs  

E-Print Network (OSTI)

modeling fluid and heat flow in fractured porous media, Soc.flow through unsaturated fractured porous media, Proceedings of the Second International Symposium on Dynamics of Fluids

Wu, Yu-Shu; Pruess, Karsten

2004-01-01T23:59:59.000Z

408

Numerical modelling of heat and mass transfer and optimisation of a natural draft wet cooling tower.  

E-Print Network (OSTI)

??The main contribution of this work is to answer several important questions relating to natural draft wet cooling tower (NDWCT) modelling, design and optimisation. Specifically,… (more)

Williamson, Nicholas J

2007-01-01T23:59:59.000Z

409

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

E-Print Network (OSTI)

media and land surface subsidence: Proceedings, 12th AnnualSymnposium on Land Subsidence, Anaheim, California 9A. Witherspoon, 1977a, Modeling subsidence due to geothermal

Wang, J.S.Y.

2013-01-01T23:59:59.000Z

410

Numerical Modeling of Heat Pipe Radiator and Fin Size Optimization for Low and No Gravity Environments.  

E-Print Network (OSTI)

??A heat-pipe radiator element has been designed and modeled to study the efficiency of heat transfer for low and no gravity environments, like in lunar… (more)

Bieger, Virginia Ruth

2013-01-01T23:59:59.000Z

411

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

412

Characterization of structural properties and dynamic behavior using distributed accelerometer networks and numerical modeling  

E-Print Network (OSTI)

Both vibration-based structural health monitoring methodologies and seismic performance analysis rely on estimates of the base-line dynamic behavior of a structure. A common method for making this estimate is through ...

Trocha, Peter Adam

2013-01-01T23:59:59.000Z

413

Numerical Modeling of Coupled Variably-Saturated Fluid Flow and Reactive Transport with Fast and Slow Chemical Reactions  

SciTech Connect

The couplings among chemical reaction rates, advective and diffusive transport in fractured media or soils, and changes in hydraulic properties due to precipitation and dissolution within fractures and in rock matrix are important for both nuclear waste disposal and remediation of contaminated sites. This paper describes the development and application of LEHGC2.0, a mechanistically-based numerical model for simulation of coupled fluid flow and reactive chemical transport including both fast and slow reactions invariably saturated media. Theoretical bases and numerical implementations are summarized, and two example problems are demonstrated. The first example deals with the effect of precipitation-dissolution on fluid flow and matrix diffusion in a two-dimensional fractured media. Because of the precipitation and decreased diffusion of solute from the fracture into the matrix, retardation in the fractured medium is not as large as the case wherein interactions between chemical reactions and transport are not considered. The second example focuses on a complicated but realistic advective-dispersive-reactive transport problem. This example exemplifies the need for innovative numerical algorithms to solve problems involving stiff geochemical reactions.

LI, MING-HSU; SIEGEL, MALCOLM D.; YEH, GOUR-TSYH (GEORGE)

1999-09-20T23:59:59.000Z

414

Numerical modeling of electrochemical-mechanical interactions in lithium polymer batteries  

Science Conference Proceedings (OSTI)

This paper presents a multi-scale finite element approach for lithium batteries to study electrochemical-mechanical interaction phenomena at macro- and micro-scales. The battery model consists of a lithium foil anode, a separator, and a porous cathode ... Keywords: Finite element method, Homogenization, Multi-scale modeling, Porous electrode theory

Stephanie Golmon; Kurt Maute; Martin L. Dunn

2009-12-01T23:59:59.000Z

415

A numerical model of hydro-thermo-mechanical coupling in a fractured rock mass  

DOE Green Energy (OSTI)

Coupled hydro-thermo-mechanical codes with the ability to model fractured materials are used for predicting groundwater flow behavior in fractured aquifers containing thermal sources. The potential applications of such a code include the analysis of groundwater behavior within a geothermal reservoir. The capability of modeling hydro-thermo systems with a dual porosity, fracture flow model has been previously developed in the finite element code, FEHM. FEHM has been modified to include stress coupling with the dual porosity feature. FEHM has been further developed to implicitly couple the dependence of fracture hydraulic conductivity on effective stress within two dimensional, saturated aquifers containing fracture systems. The cubic law for flow between parallel plates was used to model fracture permeability. The Bartin-Bandis relationship was used to determine the fracture aperture within the cubic law. The code used a Newton Raphson iteration to implicitly solve for six unknowns at each node. Results from a model of heat flow from a reservoir to the moving fluid in a single fracture compared well with analytic results. Results of a model showing the increase in fracture flow due to a single fracture opening under fluid pressure compared well with analytic results. A hot dry rock, geothermal reservoir was modeled with realistic time steps indicating that the modified FEHM code does successfully model coupled flow problems with no convergence problems.

Bower, K.M.

1996-06-01T23:59:59.000Z

416

FITOVERT: A dynamic numerical model of subsurface vertical flow constructed wetlands  

Science Conference Proceedings (OSTI)

This paper introduces a mathematical model (FITOVERT) specifically developed to simulate the behaviour of vertical subsurface flow constructed wetlands (VSSF-CWs). One of the main goals of the development of FITOVERT was to keep the complexity of the ... Keywords: Constructed wetlands, Hydrodynamics, Modelling, Reactive transport, Unsaturated flow, Vertical subsurface flow

D. Giraldi; M. de Michieli Vitturi; R. Iannelli

2010-05-01T23:59:59.000Z

417

Numerical Extended-Range Prediction: Forecast Skill Using a Low-Resolution Climate Model  

Science Conference Proceedings (OSTI)

A pilot study that evaluates the potential forecast skill of winter 10–30-day time-mean flow from a low-resolution (R15) climate simulation model is presented. The hypothesis tested is that low-resolution climate model forecasts might be as ...

David P. Baumhefner

1996-09-01T23:59:59.000Z

418

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

DOE Green Energy (OSTI)

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

419

Appendix model performance - model documentation renewable fuels module of the National Energy Modeling System  

DOE Green Energy (OSTI)

This appendix discusses performance aspects of the Renewable Fuels Module (RFM). It is intended to present the pattern of response of the RFM to typical changes in its major inputs from other NEMS modules. The overall approach of this document, with the particular statistics presented, is designed to be comparable with similar analyses conducted for all of the modules of NEMS. While not always applicable, the overall approach has been to produce analyses and statistics that are as comparable as possible with model developer`s reports for other NEMS modules. Those areas where the analysis is somewhat limited or constrained are discussed. Because the RFM consists of independent submodules, this appendix is broken down by submodule.

Not Available

1994-09-01T23:59:59.000Z

420

Numerical Modeling of 90Sr and 137Cs Transport from a Spill in the B-Cell of the 324 Building, Hanford Site 300 Area  

SciTech Connect

To characterize the extent of contamination under the 324 Building, a pit was excavated on the north side of the building in 2010 by Washington Closure Hanford LLC (WCH). Horizontal closed-end steel access pipes were installed under the foundation of the building from this pit and were used for measuring temperatures and exposure rates under the B-Cell. The deployed sensors measured elevated temperatures of up to 61 C (142 F) and exposure rates of up to 8,900 R/hr. WCH suspended deactivation of the facility because it recognized that building safety systems and additional characterization data might be needed for remediation of the contaminated material. The characterization work included additional field sampling, laboratory measurements, and numerical flow and transport modeling. Laboratory measurements of sediment physical, hydraulic, and geochemical properties were performed by Pacific Northwest National Laboratory (PNNL) and others. Geochemical modeling and subsurface flow and transport modeling also were performed by PNNL to evaluate the possible extent of contamination in the unsaturated sand and gravel sediments underlying the building. Historical records suggest that the concentrated 137Cs- and 90Sr-bearing liquid wastes that were spilled in B-Cell were likely from a glass-waste repository testing program associated with the Federal Republic of Germany (FRG). Incomplete estimates of the aqueous chemical composition (no anion data provided) of the FRG waste solutions were entered into a geochemical speciation model and were charge balanced with nitrate to estimate waste composition. Additional geochemical modeling was performed to evaluate reactions of the waste stream with the concrete foundation of the building prior to the stream entering the subsurface.

Rockhold, Mark L.; Bacon, Diana H.; Freedman, Vicky L.; Lindberg, Michael J.; Clayton, Ray E.

2012-03-19T23:59:59.000Z

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

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

Science Conference Proceedings (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

422

A Numerical Modeling Study of the Propagation of Idealized Sea-Breeze Density Currents  

Science Conference Proceedings (OSTI)

Sea breezes are often modeled as a wave response to transient heating in a stratified environment. They occur, however, as density currents with well-defined fronts, the understanding of which rests primarily on experiments and theory that do not ...

F. J. Robinson; M. D. Patterson; S. C. Sherwood

2013-02-01T23:59:59.000Z

423

The Behavior of Gravitational Modes in Numerical Forecasts with the NCAR Community Climate Model  

Science Conference Proceedings (OSTI)

Characteristics of gravitational-wave noise in noninitialized forecasts were investigated with the NCAR Community Climate Model. Forecasts were begun from FGGE analyses. The behavior of individual, gravitational normal modes was examined. In ...

R. M. Errico; D. L. Williamson

1988-09-01T23:59:59.000Z

424

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

425

Quadratic Galerkin Finite Element Schemes for the Vertical Discretization of Numerical Forecast Models  

Science Conference Proceedings (OSTI)

A finite element scheme with second-order basis functions is introduced for vertical discretization using a spectral model for horizontal discretization. The basis functions are required to be continuous, and no assumption is made concerning the ...

J. Steppeler

1987-08-01T23:59:59.000Z

426

Numerical Investigations with a Hybrid Isentropic?Sigma Model. Part II: The Inclusion of Moist Processes  

Science Conference Proceedings (OSTI)

The main goals of this paper are 1) to demonstrate the feasibility of incorporating a prognostic equation for water vapor and diabatic processes in the University of Wisconsin ??? model discussed in Part I, 2) to document methods applied to ...

Tom H. Zapotocny; Fred M. Reames; R. Bradley Pierce; Donald R. Johnson; Bart J. Wolf

1991-09-01T23:59:59.000Z

427

Numerical study of roughness distributions in nonlinear models of interface growth  

E-Print Network (OSTI)

We analyze the shapes of roughness distributions of discrete models in the Kardar, Parisi and Zhang (KPZ) and in the Villain, Lai and Das Sarma (VLDS) classes of interface growth, in one and two dimensions. Three KPZ models in d=2 confirm the expected scaling of the distribution and show a stretched exponential tail approximately as exp[-x^(0.8)], with a significant asymmetry near the maximum. Conserved restricted solid-on-solid models belonging to the VLDS class were simulated in d=1 and d=2. The tail in d=1 has the form exp(-x^2) and, in d=2, has a simple exponential decay, but is quantitatively different from the distribution of the linear fourth-order (Mullins-Herring) theory. It is not possible to fit any of the above distributions to those of 1/f^\\alpha noise interfaces, in contrast with recently studied models with depinning transitions.

Fabio D. A. Aarão Reis

2005-08-09T23:59:59.000Z

428

Numerical Simulations of Observed Arctic Stratus Clouds Using a Second-Order Turbulence Closure Model  

Science Conference Proceedings (OSTI)

A high-resolution one-dimensional version of a second-order turbulence closure radiative-convective model, developed at Los Alamos National Laboratory, is used to simulate the interactions among turbulence, radiation, and bulk cloud parameters in ...

W. S. Smith; C-Y. J. Kao

1996-01-01T23:59:59.000Z

429

The influence of Microphysics in the Formation of Intense Wake Lows: A Numerical Modeling Study  

Science Conference Proceedings (OSTI)

A two-dimensional cloud model is used to investigate whether microphysical processes alone within the stratiform rain regions of mesoscale convection systems can induce strong descent and intense surface wake lows accompanying such systems. ...

William A. Gallus Jr.

1996-10-01T23:59:59.000Z

430

Numerical Modeling of the Turbulent Fluxes of Chemically Reactive Trace Gases in the Atmospheric Boundary Layer  

Science Conference Proceedings (OSTI)

Turbulent fluxes of chemically reactive trace gases in the neutral atmospheric boundary layer (ABL) were simulated with a one-dimensional, coupled diffusion-chemistry model. The effects of rapid chemical reactions were included with a suite of ...

W. Gao; M. L. Wesely

1994-07-01T23:59:59.000Z

431

A Verification of Numerical Model Forecasts for Sounding-Derived Indices above Udine, Northeast Italy  

Science Conference Proceedings (OSTI)

In this work, 40 different indices derived from real soundings and the corresponding ECMWF model forecasts for the same location (near Udine, northeast Italy) are compared. This comparison is repeated for more than 500 days, from June 2004 to ...

Agostino Manzato

2008-06-01T23:59:59.000Z

432

A Numerical Model Study of Nocturnal Drainage Flows with Strong Wind and Temperature Gradients  

Science Conference Proceedings (OSTI)

A second-moment turbulence-closure model described in Yamada and Bunker is used to simulate nocturnal drainage flows observed during the 1984 ASCOT field expedition in Brush Creek, Colorado. In order to simulate the observed strong wind ...

T. Yamada; S. Bunker

1989-07-01T23:59:59.000Z

433

A Unified Representation of Deep Moist Convection in Numerical Modeling of the Atmosphere. Part I  

Science Conference Proceedings (OSTI)

A generalized framework for cumulus parameterization applicable to any horizontal resolution between those typically used in general circulation and cloud-resolving models is presented. It is pointed out that the key parameter in the ...

Akio Arakawa; Chien-Ming Wu

2013-07-01T23:59:59.000Z

434

Numerical Prediction of an Antarctic Severe Wind Event with the Weather Research and Forecasting (WRF) Model  

Science Conference Proceedings (OSTI)

This study initiates the application of the maturing Weather Research and Forecasting (WRF) model to the polar regions in the context of the real-time Antarctic Mesoscale Prediction System (AMPS). The behavior of the Advanced Research WRF (ARW) ...

Jordan G. Powers

2007-09-01T23:59:59.000Z

435

Numerical Simulations and a Conceptual Model of the Stratocumulus to Trade Cumulus Transition  

Science Conference Proceedings (OSTI)

A two-dimensional eddy-resolving model is used to study the transition from the stratocumulus topped boundary layer to the trade cumulus boundary layer. The 10-day simulations use an idealized Lagrangian trajectory representative of summertime ...

Matthew C. Wyant; Christopher S. Bretherton; Hugh A. Rand; David E. Stevens

1997-01-01T23:59:59.000Z

436

Oblique, Stratified Winds about a Shelter Fence. Part II: Comparison of Measurements with Numerical Models  

Science Conference Proceedings (OSTI)

To evaluate Reynolds-averaged Navier–Stokes (RANS) models of disturbed micrometeorological winds, steady-state computations using a second-order closure are compared with observations (see Part I) in which the surface layer wind was disturbed by ...

John D. Wilson

2004-10-01T23:59:59.000Z

437

Mesoscale Forecasts Generated from Operational Numerical Weather-Prediction Model Output  

Science Conference Proceedings (OSTI)

A technique called Model Output Enhancement (MOE) has been developed for the generation and display of mesoscale weather forecasts. The MOE technique derives mesoscale or high-resolution (order of 1 km) weather forecasts from synoptic-scale ...

John G. W. Kelley; Joseph M. Russo; Toby N. Carlson; J. Ronald Eyton

1988-01-01T23:59:59.000Z

438

The Formation and Fate of a River Plume: A Numerical Model  

Science Conference Proceedings (OSTI)

A mathematical model that describes the formation and dilution of a frontally bounded river plume is presented. Such features were first studied at the mouth of the Connecticut River during periods of high discharge and have subsequently been ...

James O'Donnell

1990-04-01T23:59:59.000Z

439

Sensors and Actuators B 94 (2003) 8198 Numerical modeling of transport and accumulation of DNA on  

E-Print Network (OSTI)

, and entomologists who informed Jake Kosek's ethnographic account of drone aircraft in the hills of Afghanistan and Pakistan, programmed with algorithms modeled on bee behavior to adopt "swarming" tactics (Kosek this issue

Kassegne, Samuel Kinde

440

Numerical Treatment of Cross-Shelf Open Boundaries in a Barotropic Coastal Ocean Model  

Science Conference Proceedings (OSTI)

Using a barotropic coastal ocean model with a straight coastline and uniform cross-shelf bottom slope, seven different cross-shelf open boundary conditions (four of which are applied in either implicit or explicit form) are compared in three ...

David C. Chapman

1985-08-01T23:59:59.000Z

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

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

Science Conference Proceedings (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

442

Stochastic PV performance/reliability model : preview of alpha version.  

DOE Green Energy (OSTI)

Problem Statement: (1) Uncertainties in PV system performance and reliability impact business decisions - Project cost and financing estimates, Pricing service contracts and guarantees, Developing deployment and O&M strategies; (2) Understanding and reducing these uncertainties will help make the PV industry more competitive (3) Performance has typically been estimated without much attention to reliability of components; and (4) Tools are needed to assess all inputs to the value proposition (e.g., LCOE, cash flow, reputation, etc.). Goals and objectives are: (1) Develop a stochastic simulation model (in GoldSim) that can represent PV system performance as a function of system design, weather, reliability, and O&M policies; (2) Evaluate performance for an example system to quantify sources of uncertainty and identify dominant parameters via a sensitivity study; and (3) Example System - 1 inverter, 225 kW DC Array latitude tilt (90 strings of 12 modules {l_brace}1080 modules{r_brace}), Weather from Tucumcari, NM (TMY2 with annual uncertainty).

Stein, Joshua S.; Miller, Steven P.

2010-03-01T23:59:59.000Z

443

A real-time emergency response workstation using a 3-D numerical model initialized with sodar  

Science Conference Proceedings (OSTI)

Many emergency response dispersion modeling systems provide simple Gaussian models driven by single meteorological tower inputs to estimate the downwind consequences from accidental spills or stack releases. Complex meteorological or terrain settings demand more sophisticated resolution of the three-dimensional structure of the atmosphere to reliably calculate plume dispersion. Mountain valleys and sea breeze flows are two common examples of such settings. To address these complexities, the authors have implemented the three-dimensional diagnostic MATHEW mass-adjusted wind field and ADPIC particle-in-cell dispersion models on a workstation for use in real-time emergency response modeling. MATHEW/ADPIC have shown their utility in a variety of complex settings over the last 15 years within the Department of Energy`s Atmospheric Release Advisory Capability (ARAC) project. The models are initialized using an array of surface wind measurements from meteorological towers coupled with vertical profiles from an acoustic sounder (sodar). The workstation automatically acquires the meteorological data every 15 minutes. A source term is generated using either defaults or a real-time stack monitor. Model outputs include contoured isopleths displayed on site geography or plume densities shown over 3-D color shaded terrain. The models are automatically updated every 15 minutes to provide the emergency response manager with a continuous display of potentially hazardous ground-level conditions if an actual release were to occur. Model run time is typically less than 2 minutes on 6 megaflop ({approximately}30 MIPS) workstations. Data acquisition, limited by dial-up modem communications, requires 3 to 5 minutes.

Lawver, B.S.; Sullivan, T.J. [Lawrence Livermore National Lab., CA (US); Baskett, R.L. [EG& G Energy Measurements, Inc., Pleasanton, CA (US)

1993-01-28T23:59:59.000Z

444

Final Report: A Model Management System for Numerical Simulations of Subsurface Processes  

SciTech Connect

The DOE and several other Federal agencies have committed significant resources to support the development of a large number of mathematical models for studying subsurface science problems such as groundwater flow, fate of contaminants and carbon sequestration, to mention only a few. This project provides new tools to help decision makers and stakeholders in subsurface science related problems to select an appropriate set of simulation models for a given field application.

Zachmann, David

2013-10-07T23:59:59.000Z

445

A Finite-Element Model of the Atmospheric Boundary Layer Suitable for Use with Numerical Weather Prediction Models  

Science Conference Proceedings (OSTI)

We give a detailed description of an atmospheric boundary layer model capable of simulating the diurnal cycles of wind, temperature and humidity. The model includes a formulation of various physical processes (radiative effects, variation of soil ...

J. Mailhot; R. Benoit

1982-10-01T23:59:59.000Z

446

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

Science Conference Proceedings (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

447

Use of high performance computing resources for underwater acoustic modeling.  

Science Conference Proceedings (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

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

2009-01-01T23:59:59.000Z

448

Numerical model for the vacuum pyrolysis of scrap tires in batch reactors  

Science Conference Proceedings (OSTI)

A quantitative model for scrap tire pyrolysis in a batch scale reactor developed comprises the following basic phenomena: conduction inside tire particles; conduction, convection, and radiation between the feedstock particles or between the fluids and the particles; tire pyrolysis reaction; exothermicity and endothermicity caused by tire decomposition and volatilization; and the variation of the composition and the thermal properties of tire particles. This model was used to predict the transient temperature and density distributions in the bed of particles, the volatile product evolution rate, the mass change, the energy consumption during the pyrolysis process, and the pressure history in a tire pyrolysis reactor with a load of 1 kg. The model predictions agree well with independent experimental data.

Yang, J.; Tanguy, P.A.; Roy, C. [Univ. Laval, Quebec, PQ (Canada). Dept. de Genie Chimique

1995-06-01T23:59:59.000Z

449

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

DOE Green Energy (OSTI)

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

450

Fuel Cell Power Model for CHP and CHHP Economics and Performance Analysis (Presentation)  

DOE Green Energy (OSTI)

This presentation describes the fuel cell power model for CHP and CHHP economics and performance analysis.

Steward, D.; Penev, M.

2010-03-30T23:59:59.000Z

451

Numerical Modeling of Coupled Groundwater and Surface Water Interactions in an Urban Setting  

Science Conference Proceedings (OSTI)

The Dominguez Channel Watershed (DCW), located in the southern portion of Los Angeles County (Figure A.1), drains about 345 square miles into the Los Angeles Harbor. The cities and jurisdictions in DCW are shown in Figure A.2. The largest of these include the cities of Los Angeles, Carson, and Torrance. This watershed is unique in that 93% of its land area is highly developed (i.e. urbanized). The watershed boundaries are defined by a complex network of storm drains and flood control channels, rather than being defined by natural topography. Table (1) shows a summary of different land uses in the Dominguez Channel Watershed (MEC, 2004). The Dominguez Watershed has the highest impervious area of all watersheds in the Los Angeles region. The more impervious the surface, the more runoff is generated during a storm. Storm water runoff can carry previously accumulated contaminants and transport them into receiving water systems. Point sources such as industrial wastewater and municipal sewage as well as urban runoff from commercial, residential, and industrial areas are all recognized as contributors to water quality degradation at DWC. Section 303(d) of the 1972 Federal Clean Water Act (CWA) requires states to identify and report all waters not meeting water quality standards and to develop action plans to pursue the water quality objectives. These plans specify the maximum amount of a given pollutant that the water body of concern can receive and still meet water quality standards. Such plans are called Total Maximum Daily Loads (TMDLs). TMDLs also specify allocations of pollutant loadings to point and non-point sources taking into account natural background pollutant levels. This demonstrates the importance of utilizing scientific tools, such as flow and transport models, to identify contaminant sources, understand integrated flow paths, and assess the effectiveness of water quality management strategies. Since overland flow is a very important component of the water balance and hydrology of DCW, a parallel, distributed watershed model that treats flow in groundwater and surface water in a dynamically coupled manner will be used to build a flow model of the watershed. This coupled model forms the basis for modeling and understanding the transport of contaminants through the Dominguez Channel Watershed, which can be used in designing and implementing TMDLs to manage the water quality in this basin. In this report, the coupled surface water-groundwater flow model of DCW will be presented. This flow model was calibrated against a storm that occurred in February 21st, 2004. The model and approach are explained further in the following sections.

Rihani, J F; Maxwell, R M

2007-09-26T23:59:59.000Z

452

GATE Air-Sea Interactions II: Numerical-Model Calculation of Regional Sea-Surface Temperature Fields Using the GATE Version III Gridded Global Data Set  

Science Conference Proceedings (OSTI)

The numerical model of air-sea interaction previously described in Brown et al. (1982), Pandolfo and Jacobs (1972) and Pandolfo (1969) is applied over a limited horizontal portion of the GATE III Gridded Global Data set (including continental ...

P. S. Brown Jr.; J. P. Pandolfo; G. D. Robinson

1982-10-01T23:59:59.000Z

453

The Conversion of Total Column Ozone Data to Numerical Weather Prediction Model Initializing Fields, with Simulations of the 24–25 January 2000 East Coast Snowstorm  

Science Conference Proceedings (OSTI)

Satellites are uniquely capable of providing uniform data coverage globally. Motivated by such capability, this study builds on a previously described methodology that generates numerical weather prediction (NWP) model initial conditions (ICs) ...

Dorothy Durnford; John Gyakum; Eyad Atallah

2009-01-01T23:59:59.000Z

454

Use of a Radar Simulator on the Output Fields from a Numerical Mesoscale Model to Analyze X-Band Rain Estimators  

Science Conference Proceedings (OSTI)

A full radar simulator, which works with the 3D output fields from a numerical mesoscale model, has been developed. This simulator uses a T-matrix code to calculate synthetic radar measurements, accounts for both backscattering and propagation ...

E-P. Zahiri; M. Gosset; J-P. Lafore; V. Gouget

2008-03-01T23:59:59.000Z

455

The Use of Satellite Data in the Specification of Convective Heating for Diabatic Initialization and Moisture Adjustment in Numerical Weather Prediction Models  

Science Conference Proceedings (OSTI)

Although diabatic processes play an important role in the tropical circulation, current analysis schemes and numerical weather prediction models are unable to adequately include diabatic heating information. In this paper, procedures for using ...

Kamal Puri; M. J. Miller

1990-01-01T23:59:59.000Z

456

Probabilistic Performance Forecasting for Unconventional Reservoirs With Stretched-Exponential Model  

E-Print Network (OSTI)

Reserves estimation in an unconventional-reservoir setting is a daunting task because of geologic uncertainty and complex flow patterns evolving in a long-stimulated horizontal well, among other variables. To tackle this complex problem, we present a reserves-evaluation workflow that couples the traditional decline-curve analysis with a probabilistic forecasting frame. The stretched-exponential production decline model (SEPD) underpins the production behavior. Our recovery appraisal workflow has two different applications: forecasting probabilistic future performance of wells that have production history; and forecasting production from new wells without production data. For the new field case, numerical model runs are made in accord with the statistical design of experiments for a range of design variables pertinent to the field of interest. In contrast, for the producing wells the early-time data often need adjustments owing to restimulation, installation of artificial-lift, etc. to focus on the decline trend. Thereafter, production data of either new or existing wells are grouped in accord with initial rates to obtain common SEPD parameters for similar wells. After determining the distribution of model parameters using well grouping, the methodology establishes a probabilistic forecast for individual wells. We present a probabilistic performance forecasting methodology in unconventional reservoirs for wells with and without production history. Unlike other probabilistic forecasting tools, grouping wells with similar production character allows estimation of self-consistent SEPD parameters and alleviates the burden of having to define uncertainties associated with reservoir and well-completion parameters.

Can, Bunyamin

2011-05-01T23:59:59.000Z

457

Problem-orientable numerical algorithm for modelling multi-dimensional radiative MHD flows in astrophysics -- the hierarchical solution scenario  

E-Print Network (OSTI)

We present a hierarchical approach for enhancing the robustness of numerical solvers for modelling radiative MHD flows in multi-dimensions. This approach is based on clustering the entries of the global Jacobian in a hierarchical manner that enables employing a variety of solution procedures ranging from a purely explicit time-stepping up to fully implicit schemes. A gradual coupling of the radiative MHD equation with the radiative transfer equation in higher dimensions is possible. Using this approach, it is possible to follow the evolution of strongly time-dependent flows with low/high accuracies and with efficiency comparable to explicit methods, as well as searching quasi-stationary solutions for highly viscous flows. In particular, it is shown that the hierarchical approach is capable of modelling the formation of jets in active galactic nuclei and reproduce the corresponding spectral energy distribution with a reasonable accuracy.

A. A. Hujeirat

2004-10-26T23:59:59.000Z

458

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  Near-field (Vicinity of the Device)  Flow redirection  Interaction with marine life  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

459

Numerical test of Polyakov loop models in high temperature SU(2)  

E-Print Network (OSTI)

We study the compatibility of effective mean-field models of the Polyakov loop for the deconfined phase of SU(N) pure gauge theories with lattice data obtained for the case of SU(2), in the temperature range T_c - 4.8 T_c.

Roberto Fiore; Pietro Giudice; Alessandro Papa

2004-09-07T23:59:59.000Z

460

Dissipation and Cascades to Small Scales in Numerical Models Using a Shape-Preserving Advection Scheme  

Science Conference Proceedings (OSTI)

A nondivergent barotropic mode1 and a shallow-water model are presented that exploit a high-order shape-preserving scheme for the advection of vorticity or potential vorticity as well as tracers. The dissipation associated with the advection ...

John Thuburn

1995-06-01T23:59:59.000Z

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

Cloud-Top Entrainment Instability through Small-Scale Mixing and Its Parameterization in Numerical Models  

Science Conference Proceedings (OSTI)

In a recent paper, Kuo and Schubert demonstrated the lack of observational support for the relevance of the criterion for cloud-top entrainment instability proposed by Randall and by Deardorff. Here we derive a new criterion, based on a model of ...

M. K. MacVean; P. J. Mason

1990-04-01T23:59:59.000Z

462

Diabatic Effects on Late-Winter Cold Front Evolution: Conceptual and Numerical Model Evaluations  

Science Conference Proceedings (OSTI)

The impact of diabatic heating on late winter frontogenesis is evaluated both through conceptual scaling and the use of high-resolution Eta Model simulations of a strong but relatively dry cold surface front that occurred during the Storm-scale ...

William A. Gallus Jr.; Moti Segal

1999-07-01T23:59:59.000Z

463

Infrared Cooling in Cloudy Atmospheres: Precision of Grid Point Selection for Numerical Models  

Science Conference Proceedings (OSTI)

The infrared layer temperature change in a cloudy atmosphere normally shows warming at the base of the cloud and intense cooling at the top of the cloud. In a model that uses broad-band radiative transfer to calculate atmospheric temperature ...

L. P. Stearns

1983-07-01T23:59:59.000Z

464

Improved computational schemes for the numerical modeling of hydrothermal resources in Wyoming  

DOE Green Energy (OSTI)

A new method, the Conjugate Gradient Squared (CGS) solution technique, is shown to be extremely effective when applied to the finite-difference solution of conductive and convective heat transfer in geologic systems. The CGS method is compared to the Successive Over/Under Relaxation schemes, a version of the Gaussian elimination method, and the Generalized Minimum Residual (GMRES) approach. The CGS procedure converges at least ten times faster than the nearest competitor. The model is applied to the Thermopolis hydrothermal system, located in northwestern Wyoming. Modeled results are compared with measured temperature-depth profiles and results from other studies. The temperature decrease from 72{degree}C to 54{degrees}C along the crest of the Thermopolis anticline is shown to result from cooling of the geothermal fluid as it moves to the southeast. Modeled results show correct general trends, however, a time-varying three-dimensional model will be needed to fully explain the effects of mixing within the aquifers along the crest of the anticline and thermal affects of surface surface topography. 29 refs., 18 figs., 2 tabs.

Heasler, H.P.; George, J.H.; Allen, M.B.

1990-05-01T23:59:59.000Z

465

The Numerical Modeling for Electrical Behavior of Graphene Nanoribbon in the Present of Optical Detection  

Science Conference Proceedings (OSTI)

A physical model is presented for GNR based photo detector. The photo detector structure is photodiode in which GNR is inserted between two electrodes as a tool for changing pick frequency of absorption. Optical properties of GNR discussed using tight-binding ... Keywords: Graphene Nanoribbon, Optical properties, Optical Detection

Mohammad Hosein Sheikhi; Masoud Berahman; Reza Alaei

2009-12-01T23:59:59.000Z

466

A review of Vlasov-Fokker-Planck numerical modeling of inertial confinement fusion plasma  

Science Conference Proceedings (OSTI)

The interaction of intense lasers with solid matter generates a hot plasma state that is well described by the Vlasov-Fokker-Planck equation. Accurate and efficient modeling of the physics in these scenarios is highly pertinent, because it relates to ... Keywords: Computational, Fast electron transport, Fokker-Planck, Inertial confinement fusion, Laser, Magnetic field, Plasma, Vlasov

A. G. R. Thomas; M. Tzoufras; A. P. L. Robinson; R. J. Kingham; C. P. Ridgers; M. Sherlock; A. R. Bell

2012-02-01T23:59:59.000Z

467

Numerical Simulation of Flow around a Tall Isolated Seamount. Part I: Problem Formulation and Model Accuracy  

Science Conference Proceedings (OSTI)

A sigma coordinate ocean circulation model is employed to study flow trapped to a tall seamount in a periodic f-plane channel. In Part I, errors arising from the pressure gradient formulation in the steep topography/strong stratification limit ...

Aike Beckmann; Dale B. Haidvogel

1993-08-01T23:59:59.000Z

468

Handbook of SiC Properties for Fuel Performance Modeling  

SciTech Connect

The SiC layer integrity in the TRISO-coated gas-reactor fuel particle is critical to the performance, allowed burn-up, and hence intrinsic efficiency of high temperature gas cooled reactors. While there has been significant developmental work on manufacturing the fuel particles, detailed understanding of what effects the complex in-service stress state combined with realistic materials property data under irradiation has on fuel particle survival is not adequately understood. This fact particularly frustrates the modeling efforts that seek to improve fuel performance through basic understanding. In this work the properties of SiC in the non-irradiated and irradiated condition are reviewed and analyzed in terms of applicability to TRISO fuel modeling. In addition to a review of literature data, new data has been generated to fill-in holes in the existing database, specifically in the high-temperature irradiation regime. Another critical piece of information, the strength of the SiC/Pyrolytic carbon interface, is measured and a formalism for its analysis presented. Finally, recommended empirical treatments of the data are suggested.

Snead, Lance Lewis [ORNL; Nozawa, Takashi [ORNL; Katoh, Yutai [ORNL; Byun, Thak Sang [ORNL; Kondo, Sosuke [ORNL; Petti, David [Idaho National Laboratory (INL)

2007-01-01T23:59:59.000Z

469

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

470

Modeling operator performance in low task load supervisory domains  

E-Print Network (OSTI)

Currently, numerous automated systems need constant monitoring but require little to no operator interaction for prolonged periods, such as unmanned aerial systems, nuclear power plants, and air traffic management systems. ...

Mkrtchyan, Armen A

2011-01-01T23:59:59.000Z

471

The January and July Performance of the OSU Two-Level Atmospheric General Circulation Model  

Science Conference Proceedings (OSTI)

A modified version of the two-level atmospheric general circulation model has been developed and used in the simulation of January and July global climates. The overall physical and numerical formulation of this Oregon State University (OSU) ...

Michael E. Schlesinger; W. Lawrence Gates

1980-09-01T23:59:59.000Z

472

Numerical simulation of self-induced rainout using a dynamic convective cloud model  

Science Conference Proceedings (OSTI)

The hypothesis that self-induced rainout can occur is supported by observations in Hiroshima and Nagasaki, where deposition of weapons debris with precipitation occurred several km downwind of the burst point. This precipitation was initiated either directly by the nuclear weapons or by the ensuing fires. Simulation of the Nagasaki event with a convection cloud precipitation scavenging model, although fraught with many questionable assumptions, agrees surprisingly well with the observations and supports the hypothesis that self-induced rainout can occur.

Molenkamp, C.R.

1980-03-01T23:59:59.000Z

473

Numerical simulations and predictive models of undrained penetration in soft soils  

E-Print Network (OSTI)

There are two aspects in this study: cylinder penetrations and XBP (Expendable Bottom Penetrometer) interpretations. The cylinder studies firstly investigate the relationship between the soil resisting force and penetration depth by a series 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 of rate-dependent plasticity. With all forces acting on the cylinder estimated, penetration depths are predicted from simple equations of motion for a single particle. Comparisons to experimental results show reasonable agreement between model predictions and measurements. The XBP studies follow the same methodology in investigating the soil shearing resistance as a function of penetration depth and velocity by finite element analyses. With the measurements of time decelerations during penetration of the XBP, sediment shear strength profile is inferred from a single particle kinetic model. The predictions compare favorably with experimental measurements by vane shear tests.

Shi, Han

2005-08-01T23:59:59.000Z

474

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

Science Conference Proceedings (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

475

Development of numerical models of vertical ground heat exchangers and experimental verification : domain decomposition and state model reduction approach.  

E-Print Network (OSTI)

??Ground-source heat pump systems with vertical ground heat exchangers (GHE) are gaining popularity worldwide for their higher coefficients of performance and lower CO2 emissions. However,… (more)

KIM, Eui-Jong

2011-01-01T23:59:59.000Z

476

FOUR-FLUID MODEL AND NUMERICAL SIMULATIONS OF MAGNETIC STRUCTURES IN THE HELIOSHEATH  

Science Conference Proceedings (OSTI)

The first part of this paper extends the three-fluid model of Avinash and Zank for magnetic structures in the heliosheath to a four-fluid model consisting of electrons, pick-up ions (PUIs), solar wind ions (SWIs), and neutral hydrogen. The PUIs are generated by neutrals via charge exchange with SWI. Since the kinetic pressure of PUI is nearly three to four times the pressure of SWI, these are more suited to mediate small-scale structures in the heliosheath such as magnetic holes (MH)/humps etc. The constant energy exchange between these two fluids drives them nonadiabatic. The PUIs are isothermal ({gamma} = 1) while SWIs are nonadiabatic with an index {gamma} {approx} 1.25. The four-fluid model captures these effects via a modified equation of state for PUI and SWI. The phase space of time-independent solutions in terms of the Mach numbers of PUI and SWI is constructed to delineate the parameter space which allows structure formation in the heliosheath. The second part of the paper examines the stability of the time-independent solutions computed in the first part by evolving them via a full system of Hall-MHD equations. The simulation results show that these solutions are not quite stable. As the structure propagates it develops growing oscillations in the wings. Concomitantly, there are changes in the amplitude and width of the structure. This instability could be due to local changes in the velocity of the structure and reflects an exchange between the kinetic and magnetic parts of the total energy. Our results about the presence of growing oscillations in the wings of solitary wave solutions are consistent with the recent analysis of MHs in the heliosheth by Burlaga et al. Their analysis also shows evidence for the presence of oscillations and instabilities in the wings of MHs in the heliosheath.

Avinash, K. [Department of Physics and Astrophysics, University of Delhi, 110007, India. (India); Cox, Sean M.; Shaikh, Dastgeer; Zank, G. P. [Centre for Space Plasma and Aeronomic Research, University of Alabama, Hunstville, AL 35899 (United States)

2009-04-10T23:59:59.000Z

477

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

DOE Green Energy (OSTI)

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

478

Shocktube driven BiF visible chemical laser. I - Numerical modeling of combustion driven shocktube experiments  

SciTech Connect

Calculations to determine the utility of an HF combustion-driven shocktube in the development of BiF(A-X) visible chemical lasers are presented. The calculations were performed with a one-dimensional reactive-flow Euler solver. The Euler solver uses a time-step split algorithm to advance the calculation over a time interval. A robust design can be developed that will simulate the heating produced in the FN3/TMB/He laser-gas mixture by a CO2 laser. Small amounts of water need to be included in the H2/F2/He driver gas mixture to assist in the thermalization of the vibrationally hot HF. 8 refs.

Smith, W.; Acebal, R.; Benard, D.J.; Graves, B. (Science Applications International Corp., Marietta, GA (United States) Rockwell International Science Center, Thousand Oaks, CA (United States) U.S. Army, Missile Command, Redstone Arsenal, AL (United States))

1992-07-01T23:59:59.000Z

479

Abstract Numerical investigation of Hurricane Gilbert (1988) effect on the Loop Current warm core eddy (WCE) in the Gulf of Mexico is performed using the  

E-Print Network (OSTI)

eddy (WCE) in the Gulf of Mexico is performed using the Modular Ocean Model version 2 (MOM2). Results August 2006 Ã? Springer Science+Business Media B.V. 2006 #12;Caribbean. Gilbert entered the Gulf of Mexico. 1). Although the storm was much weaker when it entered the Gulf of Mexico, Gilbert maintained nearly

Raman, Sethu

480

Impacts of the Lowest Model Level Height on the Performance of Planetary Boundary Layer Parameterizations  

Science Conference Proceedings (OSTI)

The lowest model level height z1 is important in atmospheric numerical models, since surface layer similarity is applied to the height in most of the models. This indicates an implicit assumption that z1 is within the surface layer. In this study, ...

Hyeyum Hailey Shin; Song-You Hong; Jimy Dudhia

2012-02-01T23:59:59.000Z

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

A Numerical Study of Two-Dimensional Moist Baroclinic Instability  

Science Conference Proceedings (OSTI)

A study of baroclinic instability in the presence of moisture is performed with a primitive equation nonhydrostatic two-dimensional numerical model. A new assumption regarding the meridional structure of the perturbation mixing ratio is discussed ...

Maurizio Fantini

1993-05-01T23:59:59.000Z

482

A Microcomputer Model of Crossflow Cooling Tower Performance  

E-Print Network (OSTI)

The energy use characteristics of evaporative cooling towers are of interest because, although such towers are widely used in industry, they do require a substantial amount of energy. Evaporative cooling towers are basically large heat exchangers that use both sensible heat transfer and mass transfer to cool. The heat and mass transfer process for a crossflow cooling tower has been modeled on an Apple II microcomputer. Various heat loads or weather conditions can be imposed on a given tower to evaluate its response; moreover, a subprogram can evaluate pressure drop and motor/fan characteristics. Determination of the energy required to operate the tower enables its performance to be compared against energy-saving operations such as variable speed drive or changes in fill height or type.

Reichelt, G. E; Jones, J. W.

1984-01-01T23:59:59.000Z

483

Computational Human Performance Modeling For Alarm System Design  

SciTech Connect

The introduction of new technologies like adaptive automation systems and advanced alarms processing and presentation techniques in nuclear power plants is already having an impact on the safety and effectiveness of plant operations and also the role of the control room operator. This impact is expected to escalate dramatically as more and more nuclear power utilities embark on upgrade projects in order to extend the lifetime of their plants. One of the most visible impacts in control rooms will be the need to replace aging alarm systems. Because most of these alarm systems use obsolete technologies, the methods, techniques and tools that were used to design the previous generation of alarm system designs are no longer effective and need to be updated. The same applies to the need to analyze and redefine operators’ alarm handling tasks. In the past, methods for analyzing human tasks and workload have relied on crude, paper-based methods that often lacked traceability. New approaches are needed to allow analysts to model and represent the new concepts of alarm operation and human-system interaction. State-of-the-art task simulation tools are now available that offer a cost-effective and efficient method for examining the effect of operator performance in different conditions and operational scenarios. A discrete event simulation system was used by human factors researchers at the Idaho National Laboratory to develop a generic alarm handling model to examine the effect of operator performance with simulated modern alarm system. It allowed analysts to evaluate alarm generation patterns as well as critical task times and human workload predicted by the system.

Jacques Hugo

2012-07-01T23:59:59.000Z

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Modeling and Performance of Anode-Supported SOFC  

Science Conference Proceedings (OSTI)

A "one-dimensional", steady-state model of an SOFC stack was needed to support the design of balance-of-plant components for a 5 kW mobile SOFC system. This "stack module" was required to predict appropriate stack voltage responses to changes in fuel composition, fuel flow rate, stack temperature and current demand, with response characteristics that were adjustable to changes in stack component materials and dimensions as well as to electrode porosity. The spreadsheet-based stack module was derived from the work by Kim, Virkar et al (see J. Electrochem. Soc. 146(1) 69-78 (1999)), with modifications suggested by Riess and Schoonman, p291 in CRC Handbook of Electrochemistry (1997) CRC Press. The usual overpotential terms account for ohmic resistance of the cell components, losses due to charge transfer at the electrodes, and losses due to diffusion of reactants into and products out of the porous electrodes. Response of the module is compared to published cell and stack data. After fitting adjustable parameters to match particular cell performance characteristics, the module responds reasonably well to changes in temperature and fuel concentration. The module is used to analyze the performance of anode-supported cells that were fabricated at PNNL (see abstract submitted by Stevenson, Meinhardt, Simner, Habeger and Canfield, "Fabrication and Testing of Anode-Supported SOFC").

Chick, Lawrence A.; Stevenson, Jeffry W.; Meinhardt, Kerry D.; Simner, Steven P.; Jaffe, John E.; Williford, Rick E.

2001-02-28T23:59:59.000Z

485