Modeling-Computer Simulations At Stillwater Area (Wisian & Blackwell...
Activity: Modeling-Computer Simulations At Stillwater Area (Wisian & Blackwell, 2004) Exploration Activity Details Location Stillwater Area Exploration Technique...
Modeling-Computer Simulations At Nw Basin & Range Region (Pritchett...
Pritchett, 2004) Exploration Activity Details Location Northwest Basin and Range Geothermal Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not...
Modeling-Computer Simulations At Desert Peak Area (Wisian & Blackwell...
Desert Peak Area (Wisian & Blackwell, 2004) Exploration Activity Details Location Desert Peak Area Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not...
Modeling-Computer Simulations At Walker-Lane Transitional Zone...
Pritchett, 2004) Exploration Activity Details Location Walker-Lane Transition Zone Geothermal Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness...
Modeling-Computer Simulations At Fish Lake Valley Area (Deymonaz...
Additional References Retrieved from "http:en.openei.orgwindex.php?titleModeling-ComputerSimulationsAtFishLakeValleyArea(Deymonaz,EtAl.,2008)&oldid3876...
Modeling-Computer Simulations At Nevada Test And Training Range...
ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Nevada Test And Training Range Area (Sabin, Et Al., 2004) Exploration Activity Details Location...
Bürger, Raimund
-dimensional model of sedimentation of suspensions of small solid particles dispersed in a viscous fluid. This model accepted spatially one-dimensional sedimentation model [35] gives rise to one scalar, nonlinear hyperbolicINTERNATIONAL JOURNAL OF c 2011 Institute for Scientific NUMERICAL ANALYSIS AND MODELING Computing
Bürger, Raimund
-dimensional model of sedimentation of suspensions of small solid particles dispersed in a viscous fluid. This model accepted spatially one-dimensional sedimentation model [35] gives rise to one scalar, nonlinear hyperbolicINTERNATIONAL JOURNAL OF c 2012 Institute for Scientific NUMERICAL ANALYSIS AND MODELING Computing
Modeling-Computer Simulations At Central Nevada Seismic Zone...
Nevada Seismic Zone Region (Biasi, Et Al., 2009) Exploration Activity Details Location Central Nevada Seismic Zone Geothermal Region Exploration Technique Modeling-Computer...
Modeling-Computer Simulations (Gritto & Majer) | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a gHigh Plains WindInformation Mississippi's 3rdMitsubishi Acciona JV JumpModeling-Computer
Modeling-Computer Simulations At Dixie Valley Geothermal Area...
and variations in structure on a generic basin and range geothermal reservoir. Structure, heat input, and permeability were variable used in the numerical models. Dixie valley was...
Modeling-Computer Simulations At Kilauea East Rift Geothermal...
understand the heat flow patterns in the East Rift Zone Notes Three models were made from data collected in the exploratory well HGP-A. The models simulated constant heat sources...
Modeling-Computer Simulations (Combs, Et Al., 1999) | Open Energy
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia: EnergySalton Sea GeothermalSimulation
Numerical Simulation of Transpiration Cooling
to facilitate such numerical simulations for a carbon/carbon material mounted in the side wall of a hot gas channel that are able to capture a spatially varying interplay between the hot gas flow and the coolant itself. This calls for new cooling technologies, for example, in the combustion chamber of the rocket
Numerical simulation of hydraulic fracturing
Warner, Joseph Barnes
1987-01-01T23:59:59.000Z
~ared that the results of such treatments were not always adequately described by the two-dimensional models. With recent advances in hydraulic fracturing and computing technology, attempts have been made to formulate more realistic fracture models. These three...NUMERICAL SIMULATION OF HYDRAULIC FRACTURING A Thesis by JOSEPH BARNES WARNER Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1987 Maj or Subj ect...
Simulating Reionization in Numerical Cosmology
Aaron Sokasian; Tom Abel; Lars E. Hernquist
2001-05-10T23:59:59.000Z
The incorporation of radiative transfer effects into cosmological hydrodynamical simulations is essential for understanding how the intergalactic medium (IGM) makes the transition from a neutral medium to one that is almost fully ionized. Here, we present an approximate numerical method designed to study in a statistical sense how a cosmological density field is ionized by a set of discrete point sources. A diffuse background radiation field is also computed self-consistently in our procedure. The method requires relatively few time steps and can be employed with simulations having high resolution. We describe the details of the algorithm and provide a description of how the method can be applied to the output from a pre-existing cosmological simulation to study the systematic reionization of a particular ionic species. As a first application, we compute the reionization of He II by quasars in the redshift range 3 to 6.
Numerical simulation of electrokinetically driven micro flows
Hahm, Jungyoon
2005-11-01T23:59:59.000Z
Spectral element based numerical solvers are developed to simulate electrokinetically driven flows for micro-fluidic applications. Based on these numerical solvers, basic phenomena and devices for electrokinetic applications in micro and nano flows...
The Numerical Simulation of Turbulence
W. Schmidt
2007-12-06T23:59:59.000Z
In this contribution, I give an overview of the various approaches toward the numerical modelling of turbulence, particularly, in the interstellar medium. The discussion is placed in a physical context, i. e. computational problems are motivated from basic physical considerations. Presenting selected examples for solutions to these problems, I introduce the basic ideas of the most commonly used numerical methods.
Numerical wind speed simulation model
Ramsdell, J.V.; Athey, G.F.; Ballinger, M.Y.
1981-09-01T23:59:59.000Z
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.
Numerical Simulation on Laser Fusion in China
Zhu Shaoping; Pei Wenbing; Xu Yan; Gu Peijun; Lan Ke; Ye Wenhua; Wu Junfeng; Li Jinghong; Gao Yaoming; Zheng Chunyang; Li Shuanggui; Mo Zeyao; Yan Jun [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Zhang Weiyan [National High-Tech Inertial Confinement Fusion Committee of China, Beijing 100088 (China)
2009-05-02T23:59:59.000Z
Numerical simulation is a powerful tool to get insight into the physics of laser fusion. Much effort has been devoted to develop the numerical simulation code series named LARED in China. The code series LARED are composed of six parts and enable us to have the simulation capability for the key processes in laser fusion. In recent years, a number of numerical simulations using LARED have been carried out and the simulation is checked by experiments done at the laser facility SG-II and SG-III prototype. In the present talk, some details of LARED code series will be introduced, and some simulation results, especially recent work on the opacities, will be shown.
Numerical simulations of quasar absorbers
Tom Theuns
2005-07-25T23:59:59.000Z
The physical state of the intergalactic medium can be probed in great detail with the intervening absorption systems seen in quasar spectra. The properties of the Hydrogen absorbers depend on many cosmological parameters, such as the matter-power spectrum, reionisation history, ionising background and the nature of the dark matter. The spectra also contain metal lines, which can be used to constrain the star formation history and the feedback processes acting in large and small galaxies. Simulations have been instrumental in investigating to what extent these parameters can be unambiguously constrained with current and future data. This paper is meant as an introduction to this subject, and reviews techniques and methods for simulating the intergalactic medium.
NUMERICAL SIMULATIONS OF CHROMOSPHERIC MICROFLARES
Jiang, R. L.; Fang, C.; Chen, P. F., E-mail: fangc@nju.edu.c [Department of Astronomy, Nanjing University, Nanjing 210093 (China)
2010-02-20T23:59:59.000Z
With gravity, ionization, and radiation being considered, we perform 2.5 dimensional (2.5D) compressible resistive magnetohydrodynamic (MHD) simulations of chromospheric magnetic reconnection using the CIP-MOCCT scheme. The temperature distribution of the quiet-Sun atmospheric model VALC and the helium abundance (10%) are adopted. Our 2.5D MHD simulation reproduces qualitatively the temperature enhancement observed in chromospheric microflares. The temperature enhancement DELTAT is demonstrated to be sensitive to the background magnetic field, whereas the total evolution time DELTAt is sensitive to the magnitude of the anomalous resistivity. Moreover, we found a scaling law, which is described as DELTAT/DELTAt {approx} n{sub H} {sup -1.5} B {sup 2.1}eta{sub 0} {sup 0.88}. Our results also indicate that the velocity of the upward jet is much greater than that of the downward jet, and the X-point may move up or down.
Numerical Simulations of Bouncing Jets
Bonito, Andrea; Lee, Sanghyun
2015-01-01T23:59:59.000Z
Bouncing jets are fascinating phenomenons occurring under certain conditions when a jet impinges on a free surface. This effect is observed when the fluid is Newtonian and the jet falls in a bath undergoing a solid motion. It occurs also for non-Newtonian fluids when the jets falls in a vessel at rest containing the same fluid. We investigate numerically the impact of the experimental setting and the rheological properties of the fluid on the onset of the bouncing phenomenon. Our investigations show that the occurrence of a thin lubricating layer of air separating the jet and the rest of the liquid is a key factor for the bouncing of the jet to happen. The numerical technique that is used consists of a projection method for the Navier-Stokes system coupled with a level set formulation for the representation of the interface. The space approximation is done with adaptive finite elements. Adaptive refinement is shown to be very important to capture the thin layer of air that is responsible for the bouncing.
Threedimensional numerical simulation for various geometries
Herbin, Raphaèle
modelling and numerical simulation of natural gasfed solid oxide cells (Solid Oxide Fuel Cell, SOFC) at a stationary regime. The principle of a Solid Oxide Fuel Cell (SOFC) is based on the conversion of the chemical is taken into account in the present model. The SOFC systems seem to be of great interest for use
Numerical simulation of an electroweak oscillon
Graham, N. [Department of Physics, Middlebury College, Middlebury, Vermont 05753 (United States)
2007-10-15T23:59:59.000Z
Numerical simulations of the bosonic sector of the SU(2)xU(1) electroweak standard model in 3+1 dimensions have demonstrated the existence of an oscillon--an extremely long-lived, localized, oscillatory solution to the equations of motion--when the Higgs mass is equal to twice the W{sup {+-}} boson mass. It contains total energy roughly 30 TeV localized in a region of radius 0.05 fm. A detailed description of these numerical results is presented.
NEW NUMERICAL TECHNOLOGIES FOR THE SIMULATION OF ARC WELDING PROCESSES
Paris-Sud XI, Université de
NEW NUMERICAL TECHNOLOGIES FOR THE SIMULATION OF ARC WELDING PROCESSES Michel Bellet 1 , Makhlouf Antipolis, France; soudage@transvalor.com Keywords: welding, finite elements, material deposit, adaptive for arc welding simulation and analysis. The new numerical technologies essentially consist first
Numerical Simulation of Laminar Reacting Flows with Complex Chemistry
Bell, John B.
Numerical Simulation of Laminar Reacting Flows with Complex Chemistry M S Day and J B Bell Lawrence: 47.40.Fw, 82.40.Py Submitted to: Combust. Theory Modelling #12;Numerical Simulation of Laminar
Numerical Simulations Unravel the Cosmic Web
C. -A. Faucher-Giguere; A. Lidz; L. Hernquist
2008-03-03T23:59:59.000Z
The universe is permeated by a network of filaments, sheets, and knots collectively forming a "cosmic web.'' The discovery of the cosmic web, especially through its signature of absorption of light from distant sources by neutral hydrogen in the intergalactic medium, exemplifies the interplay between theory and experiment that drives science, and is one of the great examples in which numerical simulations have played a key and decisive role. We recount the milestones in our understanding of cosmic structure, summarize its impact on astronomy, cosmology, and physics, and look ahead by outlining the challenges faced as we prepare to probe the cosmic web at new wavelengths.
Direct numerical simulation of turbulent reacting flows
Chen, J.H. [Sandia National Laboratories, Livermore, CA (United States)
1993-12-01T23:59:59.000Z
The development of turbulent combustion models that reflect some of the most important characteristics of turbulent reacting flows requires knowledge about the behavior of key quantities in well defined combustion regimes. In turbulent flames, the coupling between the turbulence and the chemistry is so strong in certain regimes that is is very difficult to isolate the role played by one individual phenomenon. Direct numerical simulation (DNS) is an extremely useful tool to study in detail the turbulence-chemistry interactions in certain well defined regimes. Globally, non-premixed flames are controlled by two limiting cases: the fast chemistry limit, where the turbulent fluctuations. In between these two limits, finite-rate chemical effects are important and the turbulence interacts strongly with the chemical processes. This regime is important because industrial burners operate in regimes in which, locally the flame undergoes extinction, or is at least in some nonequilibrium condition. Furthermore, these nonequilibrium conditions strongly influence the production of pollutants. To quantify the finite-rate chemistry effect, direct numerical simulations are performed to study the interaction between an initially laminar non-premixed flame and a three-dimensional field of homogeneous isotropic decaying turbulence. Emphasis is placed on the dynamics of extinction and on transient effects on the fine scale mixing process. Differential molecular diffusion among species is also examined with this approach, both for nonreacting and reacting situations. To address the problem of large-scale mixing and to examine the effects of mean shear, efforts are underway to perform large eddy simulations of round three-dimensional jets.
Collisionless microinstabilities in stellarators. II. Numerical simulations
Proll, J. H. E.; Xanthopoulos, P.; Helander, P. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Teilinstitut Greifswald, Wendelsteinstraße 1, 17491 Greifswald, Germany and Max-Planck/Princeton Research Center for Plasma Physics, 17491 Greifswald (Germany)] [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Teilinstitut Greifswald, Wendelsteinstraße 1, 17491 Greifswald, Germany and Max-Planck/Princeton Research Center for Plasma Physics, 17491 Greifswald (Germany)
2013-12-15T23:59:59.000Z
Microinstabilities exhibit a rich variety of behavior in stellarators due to the many degrees of freedom in the magnetic geometry. It has recently been found that certain stellarators (quasi-isodynamic ones with maximum-J geometry) are partly resilient to trapped-particle instabilities, because fast-bouncing particles tend to extract energy from these modes near marginal stability. In reality, stellarators are never perfectly quasi-isodynamic, and the question thus arises whether they still benefit from enhanced stability. Here, the stability properties of Wendelstein 7-X and a more quasi-isodynamic configuration, QIPC, are investigated numerically and compared with the National Compact Stellarator Experiment and the DIII-D tokamak. In gyrokinetic simulations, performed with the gyrokinetic code GENE in the electrostatic and collisionless approximation, ion-temperature-gradient modes, trapped-electron modes, and mixed-type instabilities are studied. Wendelstein 7-X and QIPC exhibit significantly reduced growth rates for all simulations that include kinetic electrons, and the latter are indeed found to be stabilizing in the energy budget. These results suggest that imperfectly optimized stellarators can retain most of the stabilizing properties predicted for perfect maximum-J configurations.
Numerical simulation of micro-fluidic passive and active mixers
Kumar, Saurabh
2002-01-01T23:59:59.000Z
Numerical simulations of mixing using passive and active techniques are performed. For passive mixing, numerical modeling of a micro-fluidic device, build by Holden and Cremer, was performed. The micro-fluidic device consists of a Y...
Energy stable schemes and numerical simulations of two phase ...
Title: Energy stable schemes and numerical simulations of two phase complex fluids by the phase-field method Abstact: We present an energetic variational ...
Direct numerical simulations of convective heat transfer
Pointel, G.; Acharya, S.; Sharma, C. [Louisiana State Univ., Baton Rouge, LA (United States). Mechanical Engineering Dept.
1996-11-01T23:59:59.000Z
This paper deals with the development of a direct numerical simulation (DNS) code for solving the incompressible Navier-Stokes equation using higher order finite difference schemes. The time dependent Navier Stokes equation has been discretized using semi-implicit second order time splitting scheme, which requires the solution of pressure Poisson equation. For this purpose a Galerkin Fourier transform in the spanwise direction and a matrix diagonalization technique is used. The convection terms are formulated in non-conservative form on a collocated grid. A fifth order upwind biased scheme is used for this purpose. Diffusion terms are differenced using a sixth order central difference scheme. The algorithm is implemented on the MasPar MP-1, a Single Instruction Multiple Data computer where efficient data parallelization is used to get DNS results. The code has been used to get results for smooth channel flow at Re{sub {tau}} = 180. Results are now being obtained for the energy equation and for flow in a periodic ribbed channel.
Direct numerical simulations of aeolian sand ripples
Orencio Duran; Philippe Claudin; Bruno Andreotti
2014-11-07T23:59:59.000Z
Aeolian sand beds exhibit regular patterns of ripples resulting from the interaction between topography and sediment transport. Their characteristics have been so far related to reptation transport caused by the impacts on the ground of grains entrained by the wind into saltation. By means of direct numerical simulations of grains interacting with a wind flow, we show that the instability turns out to be driven by resonant grain trajectories, whose length is close to a ripple wavelength and whose splash leads to a mass displacement towards the ripple crests. The pattern selection results from a compromise between this destabilizing mechanism and a diffusive downslope transport which stabilizes small wavelengths. The initial wavelength is set by the ratio of the sediment flux and the erosion/deposition rate, a ratio which increases linearly with the wind velocity. We show that this scaling law, in agreement with experiments, originates from an interfacial layer separating the saltation zone from the static sand bed, where momentum transfers are dominated by mid-air collisions. Finally, we provide quantitative support for the use the propagation of these ripples as a proxy for remote measurements of sediment transport.
A numerical model simulation of longshore transport for Galveston Island
Gilbreath, Stephen Alexander
1995-01-01T23:59:59.000Z
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...
Direct Numerical Simulation of the Flow in a Pebble Bed
Ward, Paul
2014-06-24T23:59:59.000Z
at Argonne National Laboratory, to conduct both large eddy simulation (LES) and direct numerical simulation (DNS) of fluid flow through a single face-centered cubic sphere lattice with periodic boundary conditions. Multiple LES were conducted with varying...
Numerical Simulation of Laminar Reacting Flows with Complex Chemistry
Bell, John B.
Numerical Simulation of Laminar Reacting Flows with Complex Chemistry M S Day and J B Bell Lawrence Simulation of Laminar Reacting Flows 2 1. Introduction Detailed modelling of time-dependent reacting ows
Numerical Simulation in Applied Geophysics. From the Mesoscale to the
Santos, Juan
Numerical Simulation in Applied Geophysics. From the Mesoscale to the Macroscale Juan E. Santos Numerical Simulation in Applied Geophysics. From the Mesoscale to the Macroscale p. #12;Introduction. I layering, fractures and craks at the mesoscale (on the order of centimeters) are common in the earth
NUMERICAL SIMULATION OF AIR POLLUTION DYNAMICS DUE TO
Olszewski Jr., Edward A.
NUMERICAL SIMULATION OF AIR POLLUTION DYNAMICS DUE TO POINT SOURCE EMISSIONS FROM AN INDUSTRIAL · Works Cited #12;Statement of the Problem · Numerical simulation of air pollution from a point source threat of air pollution Major health hazard to humans and ecosystem Billions effected, mainly
Numerical simulations of the intergalactic medium
Tom Theuns
2002-09-05T23:59:59.000Z
The intergalactic medium at redshifts 2--6 can be studied observationally through the absorption features it produces in the spectra of background quasars. Most of the UV-absorption lines arise in mildly overdense regions, which can be simulated reliably with current hydrodynamical simulations. Comparison of observed and simulated spectra allows one to put contraints on the model's parameters.
Numerical Simulation of Free Standing Hybrid Risers
Hou, Tiancong
2014-08-13T23:59:59.000Z
by the offshore industry. Furthermore, the vortex induced motion (VIM) of the buoyancy can is considered in the simulation and its effects on the motion of the FSHR are explored, which is compared with the corresponding model tests. The ability to simulate...
Numerical Simulations of MHD Turbulence in Accretion Disks
Steven A. Balbus; John F. Hawley
2002-03-20T23:59:59.000Z
We review numerical simulations of MHD turbulence. The last decade has witnessed fundamental advances both in the technical capabilities of direct numerical simulation, and in our understanding of key physical processes. Magnetic fields tap directly into the free energy sources in a sufficiently ionized gas. The result is that adverse angular velocity and adverse temperature gradients, not the classical angular momentum and entropy gradients, destabilize laminar and stratified flow. This has profound consequences for astrophysical accretion flows, and has opened the door to a new era of numerical simulation experiments.}
Numerical techniques of rigid body simulation
Eberle, David Michael
2001-01-01T23:59:59.000Z
. One of the goals of this thesis is overcoming this restriction. Collision detection is only one of the many hurdles which arise in simulating collisions between rigid bodies. To calculate the appropriate response of colliding bodies, the point...
Polarization transmission at RHIC, numerical simulations
Meot F.; Bai, M.; Liu, C.; Minty, M.; Ranjbar, V.
2012-05-20T23:59:59.000Z
Typical tracking simulations regarding the transmission of the polarization in the proton-proton collider RHIC are discussed. They participate in general studies aimed at understanding and improving polarization performances during polarized proton-proton runs.
Numerical simulation of flow separation control by oscillatory fluid injection
Resendiz Rosas, Celerino
2005-08-29T23:59:59.000Z
In this work, numerical simulations of flow separation control are performed. The sep-aration control technique studied is called 'synthetic jet actuation'. The developed code employs a cell centered finite volume scheme which handles viscous...
Numerical Simulation Study on Transpired Solar Air Collector
Wang, C.; Guan, Z.; Zhao, X.; Wang, D.
2006-01-01T23:59:59.000Z
The unglazed transpired solar air collector is now a well-recognized solar air heater for heating outside air directly. In this article, researchers introduced numerical simulation tools into the solar air collector research area, analyzed...
Numerical Simulation Study on Transpired Solar Air Collector
Wang, C.; Guan, Z.; Zhao, X.; Wang, D.
2006-01-01T23:59:59.000Z
The unglazed transpired solar air collector is now a well-recognized solar air heater for heating outside air directly. In this article, researchers introduced numerical simulation tools into the solar air collector research area, analyzed...
Wavelet methods For the numerical simulation of incompressible fluids
Starck, Jean-Luc
Wavelet methods For the numerical simulation of incompressible fluids Erwan Deriaz Erwan Numerik, Seminar February 16th 2006 0-0 #12; Wavelets for the Navier-Stokes equations homogeneous or non homogeneous) With a wavelet discretization: £ ¦ ¨ 2 ©$# £ % ¦ ¨ 2 © & '' ( 1
Direct Numerical Simulation of the Flow in a Pebble Bed
Ward, Paul
2014-06-24T23:59:59.000Z
bed reactors: dust generation and scaling, proceedings of ICAPP 2012, Chicago, June 24–28, 2012 [3] A. Shams, F. Roelofs, EMJ. Komen, E. Baglietto, 2013. “Quasi-direct numerical simulation of a pebble bed configuration. Part I: Flow (velocity...
Numerical Simulation of a Natural Circulation Steam Generator
Weinmüller, Ewa B.
Numerical Simulation of a Natural Circulation Steam Generator W. Linzer \\Lambda , K. Ponweiser circulation steam generator. We focus on a model with a simple geometry consisting of two vertical pipes properties of water and steam. We present a numerical algorithm based on an explicit upwind discretization
NUMERICAL SIMULATIONS OF TRANSVERSE COMPRESSION AND DENSIFICATION IN WOOD
Nairn, John A.
NUMERICAL SIMULATIONS OF TRANSVERSE COMPRESSION AND DENSIFICATION IN WOOD John A. Nairn1 Professor- terials is a useful tool for stress analysis and for failure modeling. Although FEA of wood as an anisotropic continuum is used, numerical modeling of realistic wood structures, including details of wood
Numerical simulation of tsunami waves generated by deformable submarine landslides
Kirby, James T.
Numerical simulation of tsunami waves generated by deformable submarine landslides Gangfeng Ma a wave model Tsunami wave Numerical modeling a b s t r a c t This paper presents a new submarine of landslide motion and associated tsunami wave generation on parameters including sediment settling velocity
Numerical and laboratory simulations of auroral acceleration
Gunell, H.; De Keyser, J. [1Belgian Institute for Space Aeronomy, Avenue Circulaire 3, B-1180 Brussels (Belgium)] [1Belgian Institute for Space Aeronomy, Avenue Circulaire 3, B-1180 Brussels (Belgium); Mann, I. [EISCAT Scientific Association, P.O. Box 812, SE-981 28 Kiruna, Sweden and Department of Physics, Umeå University, SE-901 87 Umeå (Sweden)] [EISCAT Scientific Association, P.O. Box 812, SE-981 28 Kiruna, Sweden and Department of Physics, Umeå University, SE-901 87 Umeå (Sweden)
2013-10-15T23:59:59.000Z
The existence of parallel electric fields is an essential ingredient of auroral physics, leading to the acceleration of particles that give rise to the auroral displays. An auroral flux tube is modelled using electrostatic Vlasov simulations, and the results are compared to simulations of a proposed laboratory device that is meant for studies of the plasma physical processes that occur on auroral field lines. The hot magnetospheric plasma is represented by a gas discharge plasma source in the laboratory device, and the cold plasma mimicking the ionospheric plasma is generated by a Q-machine source. In both systems, double layers form with plasma density gradients concentrated on their high potential sides. The systems differ regarding the properties of ion acoustic waves that are heavily damped in the magnetosphere, where the ion population is hot, but weakly damped in the laboratory, where the discharge ions are cold. Ion waves are excited by the ion beam that is created by acceleration in the double layer in both systems. The efficiency of this beam-plasma interaction depends on the acceleration voltage. For voltages where the interaction is less efficient, the laboratory experiment is more space-like.
AI-Based Simulation: An Alternative to Numerical Simulation and Modeling
Mohaghegh, Shahab
: Numerical Modeling, Simulation, Artificial Intelligence, Data Min- ing, Reservoir Modeling, Reservoir data for brown fields. The run-time of AI-Based reservoir models that provide complete field responses Computational Fluid Dynamics (CFD) to Numer- ical Reservoir Simulation (NRS) most of the computational modeling
Carmignani, B
2005-01-01T23:59:59.000Z
Numerical simulations of welds of thick steel pieces of interest for the thermonuclear fusion ITER machine
Numerical simulation of ceramic breeder pebble bed thermal creep behavior
Abdou, Mohamed
Numerical simulation of ceramic breeder pebble bed thermal creep behavior Alice Ying *, Hulin Huang Abstract The evolution of ceramic breeder pebble bed thermal creep deformation subjected to an external of ceramic breeder pebble beds under thermomechanical loads is necessary to ensure that the integrity of beds
Direct Numerical Simulations and Modeling of Jets in Crossflow
Mahesh, Krishnan
Direct Numerical Simulations and Modeling of Jets in Crossflow A THESIS SUBMITTED TO THE FACULTY. i #12;To my parents and my grandparents, and to Ramnath ii #12;Abstract Jets in crossflow are used to study the different aspects of round jets in a crossflow. The first problem studies
Control of Jets in Crossflow using Direct Numerical Simulations
Mahesh, Krishnan
Control of Jets in Crossflow using Direct Numerical Simulations A THESIS SUBMITTED TO THE FACULTY in crossflow by axial pulsing. Our main idea is that pulsing generates vortex rings; the effect of pulsing on jets in crossflow can therefore be explained by studying the behavior of vortex rings in crossflow
Particle acceleration in solar flares: observations versus numerical simulations
Particle acceleration in solar flares: observations versus numerical simulations A O Benz, P C processes such as isotropization and magnetic trapping are made. Keywords: Particle acceleration, hard X. As the electric field of reconnection with possible parallel component capable of particle acceleration is limited
Numerical Simulation of Titanium Production in the Plasma Quench Reactor
Numerical Simulation of Titanium Production in the Plasma Quench Reactor Ray A. Beny and Randall A the nucleation of condensates in the steady-state supersonic nozzle flow generated in a plasma quench reactor reactions. The device has been termed the Plasma Quench Reactor or PQR. The PQR has demonstrated the ability
Numerical Simulation of the December 26, 2004: Indian Ocean Tsunami
Kirby, James T.
Numerical Simulation of the December 26, 2004: Indian Ocean Tsunami J. Asavanant1, M. Ioualalen2, N. Kaewbanjak1, S. Grilli3, P. Watts4, and J. Kirby5 Abstract: The December 26, 2004 tsunami is one of the most devastating tsunami in recorded history. It was generated in the Indian Ocean off the western coast
Numerical simulation of transpiration cooling through porous , T. Gotzen1
to facilitate such numerical simulations for a carbon/carbon material mounted in the side wall of a hot gas channel that are able to capture a spatially varying interplay between the hot gas flow and the coolant itself. This calls for new cooling technologies, for example, in the combustion chamber of the rocket
Numerical Simulation of the Wave Bottom Boundary Layer
Slinn, Donald
boundary layer. Oscillatory boundary layers are examined using a high-resolution time-dependent threeNumerical Simulation of the Wave Bottom Boundary Layer Over a Smooth Surface. Part 1: Three for turbulent boundary layers that occur over a smooth bottom. Results indicate that turbulence levels
Numerical simulation of turbulent jet primary breakup in Diesel engines
Helluy, Philippe
Numerical simulation of turbulent jet primary breakup in Diesel engines Peng Zeng1 Marcus Herrmann" IRMA Strasbourg, 23.Jan.2008 #12;Introduction DNS of Primary Breakup in Diesel Injection Phase Transition Modeling Turbulence Modeling Summary Outline 1 Introduction 2 DNS of Primary Breakup in Diesel
Numerical Simulation for eHealth: Grid-enabled Medical Simulation Services Siegfried Benknera
Middleton, Stuart E.
advanced bio-medical simulation applications. Often, however, such applications have a very limited methodology advances. The European GEMSS Project [7] is concerned with the creation of medical Grid service1 Numerical Simulation for eHealth: Grid-enabled Medical Simulation Services Siegfried Benknera
NUMERICAL SIMULATION OF NATURAL GAS-SWIRL BURNER
Ala Qubbaj
2005-03-01T23:59:59.000Z
A numerical simulation of a turbulent natural gas jet diffusion flame at a Reynolds number of 9000 in a swirling air stream is presented. The numerical computations were carried out using the commercially available software package CFDRC. The instantaneous chemistry model was used as the reaction model. The thermal, composition, flow (velocity), as well as stream function fields for both the baseline and air-swirling flames were numerically simulated in the near-burner region, where most of the mixing and reactions occur. The results were useful to interpret the effects of swirl in enhancing the mixing rates in the combustion zone as well as in stabilizing the flame. The results showed the generation of two recirculating regimes induced by the swirling air stream, which account for such effects. The present investigation will be used as a benchmark study of swirl flow combustion analysis as a step in developing an enhanced swirl-cascade burner technology.
Refined numerical models for multidimensional Type Ia supernova simulations
Reinecke, M; Niemeyer, J C
2002-01-01T23:59:59.000Z
Following up on earlier work on this topic (Reinecke et al. 1999, A&A 347, pp. 724 and 739), we present an improved set of numerical models for simulations of white dwarfs exploding as Type Ia supernovae (SNe Ia). Two-dimensional simulations were used to test the reliability and numerical robustness of these algorithms; the results indicate that integral quantities like the total energy release are insensitive to changes of the grid resolution (above a certain threshold), which was not the case for our former code. The models were further enhanced to allow fully three-dimensional simulations of SNe Ia. A direct comparison of a 2D and a 3D calculation with identical initial conditions shows that the explosion is considerably more energetic in three dimensions; this is most likely caused by the assumption of axisymmetry in 2D, which inhibits the growth of flame instabilities in the azimuthal direction and thereby decreases the flame surface.
Refined numerical models for multidimensional Type Ia supernova simulations
M. Reinecke; W. Hillebrandt; J. C. Niemeyer
2001-11-26T23:59:59.000Z
Following up on earlier work on this topic (Reinecke et al. 1999, A&A 347, pp. 724 and 739), we present an improved set of numerical models for simulations of white dwarfs exploding as Type Ia supernovae (SNe Ia). Two-dimensional simulations were used to test the reliability and numerical robustness of these algorithms; the results indicate that integral quantities like the total energy release are insensitive to changes of the grid resolution (above a certain threshold), which was not the case for our former code. The models were further enhanced to allow fully three-dimensional simulations of SNe Ia. A direct comparison of a 2D and a 3D calculation with identical initial conditions shows that the explosion is considerably more energetic in three dimensions; this is most likely caused by the assumption of axisymmetry in 2D, which inhibits the growth of flame instabilities in the azimuthal direction and thereby decreases the flame surface.
A fast direct numerical simulation method for characterising hydraulic roughness
Chung, Daniel; MacDonald, Michael; Hutchins, Nicholas; Ooi, Andrew
2015-01-01T23:59:59.000Z
We describe a fast direct numerical simulation (DNS) method that promises to directly characterise the hydraulic roughness of any given rough surface, from the hydraulically smooth to the fully rough regime. The method circumvents the unfavourable computational cost associated with simulating high-Reynolds-number flows by employing minimal-span channels (Jimenez & Moin 1991). Proof-of-concept simulations demonstrate that flows in minimal-span channels are sufficient for capturing the downward velocity shift, that is, the Hama roughness function, predicted by flows in full-span channels. We consider two sets of simulations, first with modelled roughness imposed by body forces, and second with explicit roughness described by roughness-conforming grids. Owing to the minimal cost, we are able to conduct DNSs with increasing roughness Reynolds numbers while maintaining a fixed blockage ratio, as is typical in full-scale applications. The present method promises a practical, fast and accurate tool for character...
Transient productivity index for numerical well test simulations
Blanc, G.; Ding, D.Y.; Ene, A. [Institut Francais du Petrole, Pau (France)] [and others
1997-08-01T23:59:59.000Z
The most difficult aspect of numerical simulation of well tests is the treatment of the Bottom Hole Flowing (BHF) Pressure. In full field simulations, this pressure is derived from the Well-block Pressure (WBP) using a numerical productivity index which accounts for the grid size and permeability, and for the well completion. This productivity index is calculated assuming a pseudo-steady state flow regime in the vicinity of the well and is therefore constant during the well production period. Such a pseudo-steady state assumption is no longer valid for the early time of a well test simulation as long as the pressure perturbation has not reached several grid-blocks around the well. This paper offers two different solutions to this problem: (1) The first one is based on the derivation of a Numerical Transient Productivity Index (NTPI) to be applied to Cartesian grids; (2) The second one is based on the use of a Corrected Transmissibility and Accumulation Term (CTAT) in the flow equation. The representation of the pressure behavior given by both solutions is far more accurate than the conventional one as shown by several validation examples which are presented in the following pages.
Stochastic algorithms for the analysis of numerical flame simulations
Bell, John B.; Day, Marcus S.; Grcar, Joseph F.; Lijewski, Michael J.
2004-04-26T23:59:59.000Z
Recent progress in simulation methodologies and high-performance parallel computers have made it is possible to perform detailed simulations of multidimensional reacting flow phenomena using comprehensive kinetics mechanisms. As simulations become larger and more complex, it becomes increasingly difficult to extract useful information from the numerical solution, particularly regarding the interactions of the chemical reaction and diffusion processes. In this paper we present a new diagnostic tool for analysis of numerical simulations of reacting flow. Our approach is based on recasting an Eulerian flow solution in a Lagrangian frame. Unlike a conventional Lagrangian view point that follows the evolution of a volume of the fluid, we instead follow specific chemical elements, e.g., carbon, nitrogen, etc., as they move through the system . From this perspective an ''atom'' is part of some molecule of a species that is transported through the domain by advection and diffusion. Reactions cause the atom to shift from one chemical host species to another and the subsequent transport of the atom is given by the movement of the new species. We represent these processes using a stochastic particle formulation that treats advection deterministically and models diffusion and chemistry as stochastic processes. In this paper, we discuss the numerical issues in detail and demonstrate that an ensemble of stochastic trajectories can accurately capture key features of the continuum solution. The capabilities of this diagnostic are then demonstrated by applications to study the modulation of carbon chemistry during a vortex-flame interaction, and the role of cyano chemistry in rm NO{sub x} production for a steady diffusion flame.
Direct Numerical Simulation of Autoignition in a Jet in a Cross...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Direct Numerical Simulation of Autoignition in a Jet in a Cross-Flow Direct Numerical Simulation of Autoignition in a Jet in a Cross-Flow PI Name: Christos Frouzakis PI Email:...
Diffusive mesh relaxation in ALE finite element numerical simulations
Dube, E.I.
1996-06-01T23:59:59.000Z
The theory for a diffusive mesh relaxation algorithm is developed for use in three-dimensional Arbitary Lagrange/Eulerian (ALE) finite element simulation techniques. This mesh relaxer is derived by a variational principle for an unstructured 3D grid using finite elements, and incorporates hourglass controls in the numerical implementation. The diffusive coefficients are based on the geometric properties of the existing mesh, and are chosen so as to allow for a smooth grid that retains the general shape of the original mesh. The diffusive mesh relaxation algorithm is then applied to an ALE code system, and results from several test cases are discussed.
Chen, Qingyan "Yan"
save energy consumed by the heating, ventilating, and air- conditioning systems in a building1 Natural Ventilation in Buildings: Measurement in a Wind Tunnel and Numerical Simulation@purdue.edu Abstract Natural ventilation in buildings can create a comfortable and healthy indoor environment, and can
Numerical Relativity in Spherical Polar Coordinates: Off-center Simulations
Thomas W. Baumgarte; Pedro J. Montero; Ewald Müller
2015-06-03T23:59:59.000Z
We have recently presented a new approach for numerical relativity simulations in spherical polar coordinates, both for vacuum and for relativistic hydrodynamics. Our approach is based on a reference-metric formulation of the BSSN equations, a factoring of all tensor components, as well as a partially implicit Runge-Kutta method, and does not rely on a regularization of the equations, nor does it make any assumptions about the symmetry across the origin. In order to demonstrate this feature we present here several off-centered simulations, including simulations of single black holes and neutron stars whose center is placed away from the origin of the coordinate system, as well as the asymmetric head-on collision of two black holes. We also revisit our implementation of relativistic hydrodynamics and demonstrate that a reference-metric formulation of hydrodynamics together with a factoring of all tensor components avoids problems related to the coordinate singularities at the origin and on the axes. As a particularly demanding test we present results for a shock wave propagating through the origin of the spherical polar coordinate system.
Numerical simulation of the impeller tip clearance effect on centrifugal compressor performance
Hoenninger, Corbett Reed
2001-01-01T23:59:59.000Z
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...
MHD Remote Numerical Simulations: Evolution of Coronal Mass Ejections
L. Hernandez-Cervantes; A. Santillan; A. R. Gonzalez-Ponce
2008-12-22T23:59:59.000Z
Coronal mass ejections (CMEs) are solar eruptions into interplanetary space of as much as a few billion tons of plasma, with embedded magnetic fields from the Sun's corona. These perturbations play a very important role in solar--terrestrial relations, in particular in the spaceweather. In this work we present some preliminary results of the software development at the Universidad Nacional Autonoma de Mexico to perform Remote MHD Numerical Simulations. This is done to study the evolution of the CMEs in the interplanetary medium through a Web-based interface and the results are store into a database. The new astrophysical computational tool is called the Mexican Virtual Solar Observatory (MVSO) and is aimed to create theoretical models that may be helpful in the interpretation of observational solar data.
Direct numerical simulation of pattern formation in subaqueous sediment
Kidanemariam, Aman G
2014-01-01T23:59:59.000Z
We present results of direct numerical simulation of incompressible fluid flow over a thick bed of mobile, spherically-shaped particles. The algorithm is based upon the immersed boundary technique for fluid-solid coupling and uses a soft-sphere model for the solid-solid contact. Two parameter points in the laminar flow regime are chosen, leading to the emergence of sediment patterns classified as `small dunes', while one case under turbulent flow conditions leads to `vortex dunes' with significant flow separation on the lee side. Wavelength, amplitude and propagation speed of the patterns extracted from the spanwise-averaged fluid-bed interface are found to be consistent with available experimental data. The particle transport rates are well represented by available empirical models for flow over a plane sediment bed in both the laminar and the turbulent regimes.
Electromagnetic Pulse Propagation over Nonuniform Earth Surface: Numerical Simulation
Alexei V. Popov; Vladimir V. Kopeikin
2007-04-14T23:59:59.000Z
We simulate EM pulse propagation along the nonuniform earth surface using so called time-domain parabolic equation. To solve it by finite differences, we introduce a time-domain analog of the impedance boundary condition and a nonlocal BC of transparency reducing open computational domain to a strip of finite width. Numerical examples demonstrate influence of soil conductivity on the wide-band pulse waveform. For a high-frequency modulated EM pulse, we develop an asymptotic approach based on the ray structure of the monochromatic wave field at carrier frequency. This radically diminishes the computation costs and allows for pulsed wave field calculation in vast domains measured by tens of thousands wavelengths.
J. E. Taylor; Arif Babul
2000-12-14T23:59:59.000Z
We have developed a simple yet surprisingly accurate analytic scheme for tracking the dynamical evolution of substructure within larger dark halos. The scheme incorporates the effects of dynamical friction, tidal mass loss and tidal heating via physically motivated approximations. Using our scheme, we can predict the orbital evolution and mass-loss history of individual subhalos in detail. We are also able to determine the impact and importance of the different physical processes on the dynamical evolution of the subhalos. To test and calibrate this model, we compare it with a set of recent high-resolution numerical simulations of mergers between galaxies and small companions. We find that we can reproduce the orbits and mass-loss rates seen in all of these simulations with considerable accuracy, using a single set of values for the three free parameters in our model. Computationally, our scheme is more than 1000 times faster than the simplest of the high-resolution numerical simulations. This means that we can carry out detailed and statistically meaningful investigations into the characteristics of the subhalo population in different cosmologies, the stripping and disruption of the subhalos, and the interactions of the subhalos with other dynamical structures such as a thin disk. This last point is of particular interest given the ubiquity of minor mergers in hierarchical models. In this regard, our method's simplicity and speed makes it particularly attractive for incorporation into semi-analytic models of galaxy formation.
Energy and enstrophy transfer in numerical simulations of two-dimensional' turbulence
Vallis, Geoff
Energy and enstrophy transfer in numerical simulations of two-dimensional' turbulence Mathew E a significant fraction of the flow field,w and energy spectra from these simulations have slopes significantly October 1992; accepted 25 March 1993) Numerical simulations of statistically steady two-dimensional (2-D
A Flux-Limited Numerical Method for the MHD Equations to Simulate Propulsive Plasma Flows
Choueiri, Edgar
to be effective tools in plasma propulsion research, a higher order accu- rate solver that captures MHD shocks approach, numerical simulations are valuable tools in plasma thruster research. More- over, simulations can Simula- tions The importance of numerical simulation in advancing plasma thruster research was realized
Numerical simulation of oxidation and its effect on the crack growth resistance of titanium alloys
Triharjanto, Robertus Heru
1997-01-01T23:59:59.000Z
of titanium alloys used as metal matrix in MMC is imperative. This research effort develops a numerical modeling procedure to simulate the oxidation propagating from the crack surfaces and evaluate the effect on the mechanical behavior. The numerical modeling...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5(Million Cubic Feet) Oregon (Including Vehicle Fuel) (Million Cubic Feet) Natural Gas DeliveredStents -(NEI) ScienceNumerical simulations of current
Advanced Numerical Methods and Software Approaches for Semiconductor Device Simulation
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Carey, Graham F.; Pardhanani, A. L.; Bova, S. W.
2000-01-01T23:59:59.000Z
In this article we concisely present several modern strategies that are applicable to driftdominated carrier transport in higher-order deterministic models such as the driftdiffusion, hydrodynamic, and quantum hydrodynamic systems. The approaches include extensions of “upwind” and artificial dissipation schemes, generalization of the traditional Scharfetter – Gummel approach, Petrov – Galerkin and streamline-upwind Petrov Galerkin (SUPG), “entropy” variables, transformations, least-squares mixed methods and other stabilized Galerkin schemes such as Galerkin least squares and discontinuous Galerkin schemes. The treatment is representative rather than an exhaustive review and several schemes are mentioned only briefly with appropriate reference to the literature. Some of themore »methods have been applied to the semiconductor device problem while others are still in the early stages of development for this class of applications. We have included numerical examples from our recent research tests with some of the methods. A second aspect of the work deals with algorithms that employ unstructured grids in conjunction with adaptive refinement strategies. The full benefits of such approaches have not yet been developed in this application area and we emphasize the need for further work on analysis, data structures and software to support adaptivity. Finally, we briefly consider some aspects of software frameworks. These include dial-an-operator approaches such as that used in the industrial simulator PROPHET, and object-oriented software support such as those in the SANDIA National Laboratory framework SIERRA.« less
Numerical simulations of compressively driven interstellar turbulence: I. Isothermal gas
Schmidt, Wolfram; Hupp, Markus; Kern, Sebastian; Niemeyer, Jens C
2008-01-01T23:59:59.000Z
We performed numerical simulations of supersonic isothermal turbulence driven by mostly compressive large-scale forcing, using both a static grid and adaptive mesh refinement with an effective resolution N=768^3. After a transient phase dominated by shocks, turbulence evolves into a steady state with an RMS Mach number about 2.5, in which cloud-like structures of over-dense gas are surrounded by highly rarefied gas. The index of the turbulence energy spectrum function beta = 2.0 in the shock-dominated phase. As the flow approaches statistical equilibrium, the spectrum flattens, with beta = 1.9. For the scaling exponent of the root mean square velocity fluctuation, we obtain gamma = 0.43 from the velocity structure functions of second order. These results are well within the range of observed scaling properties for the velocity dispersion in molecular clouds. Calculating structure functions of order p=1,...,5, we find for all scaling exponents significant deviations from the Kolmogorov-Burgers model proposed b...
Numerical simulations of super-luminous supernovae of type IIn
Dessart, Luc; Hillier, D John
2015-01-01T23:59:59.000Z
We present numerical simulations that include 1-D Eulerian multi-group radiation-hydrodynamics, 1-D non-LTE radiative transfer, and 2-D polarised radiative transfer for super-luminous interacting supernovae (SNe). Our reference model is a ~10Msun inner shell with 10^51erg ramming into a ~3Msun cold outer shell (the circumstellar-medium, or CSM) that extends from 10^15cm to 2x10^16cm and moves at 100km/s. We discuss the light curve evolution, which cannot be captured adequately with a grey approach. In these interactions, the shock-crossing time through the optically-thick CSM is much longer than the photon diffusion time. Radiation is thus continuously leaking from the shock through the CSM, in disagreement with the shell-shocked model that is often invoked. Our spectra redden with time, with a peak distribution in the near-UV during the first month gradually shifting to the optical range over the following year. Initially Balmer lines exhibit a narrow line core and the broad line wings that are characteristi...
DIPOLE COLLAPSE AND DYNAMO WAVES IN GLOBAL DIRECT NUMERICAL SIMULATIONS
Schrinner, Martin; Dormy, Emmanuel [MAG (ENS/IPGP), LRA, Ecole Normale Superieure, 24 Rue Lhomond, 75252 Paris Cedex 05 (France); Petitdemange, Ludovic, E-mail: martin@schrinner.eu [Previously at Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg, Germany. (Germany)
2012-06-20T23:59:59.000Z
Magnetic fields of low-mass stars and planets are thought to originate from self-excited dynamo action in their convective interiors. Observations reveal a variety of field topologies ranging from large-scale, axial dipoles to more structured magnetic fields. In this article, we investigate more than 70 three-dimensional, self-consistent dynamo models in the Boussinesq approximation obtained by direct numerical simulations. The control parameters, the aspect ratio, and the mechanical boundary conditions have been varied to build up this sample of models. Both strongly dipolar and multipolar models have been obtained. We show that these dynamo regimes in general can be distinguished by the ratio of a typical convective length scale to the Rossby radius. Models with a predominantly dipolar magnetic field were obtained, if the convective length scale is at least an order of magnitude larger than the Rossby radius. Moreover, we highlight the role of the strong shear associated with the geostrophic zonal flow for models with stress-free boundary conditions. In this case the above transition disappears and is replaced by a region of bistability for which dipolar and multipolar dynamos coexist. We interpret our results in terms of dynamo eigenmodes using the so-called test-field method. We can thus show that models in the dipolar regime are characterized by an isolated 'single mode'. Competing overtones become significant as the boundary to multipolar dynamos is approached. We discuss how these findings relate to previous models and to observations.
Numerical simulations for nodal domains and spectral minimal partitions
Vial, Grégory
unpublished results of [HHO2] with efficient numerical computations. This is the main goal of this paper
Analysis of Cold Air Distribution System in an Office Building by the Numerical Simulation Method
Jian, Y.; Li, D.; Xu, H.; Ma, X.
2006-01-01T23:59:59.000Z
Numerical simulation is carried out in this paper to calculate indoor air patterns, which include angles of inlet direction and induced ratios in a typical official room. According to the simulation results, the indoor air distribution and indoor...
Analysis of Cold Air Distribution System in an Office Building by the Numerical Simulation Method
Jian, Y.; Li, D.; Xu, H.; Ma, X.
2006-01-01T23:59:59.000Z
Numerical simulation is carried out in this paper to calculate indoor air patterns, which include angles of inlet direction and induced ratios in a typical official room. According to the simulation results, the indoor air distribution and indoor...
Numerical simulation of three-dimensional electrical flow through geomaterials
Akhtar, Anwar Saeed
1998-01-01T23:59:59.000Z
95 99 V ELECTRICAL FLOW AROUND AN ELECTRICAL CONE PENETROMETER 104 5. 1 INTRODUCTION 5. 2 ANALYTICAL SOLUTION FOR ELECTRICAL FLOW AROUND AN ELECTRICAL CONE PENETROMETER 5. 3 NUMERICAL INVESTIGATION 5. 4 COMPARISON OF ANALYTICAL AND NUMERICAL... RESULTS 5. 5 CONCLUSION AND APPLICATION 5. 5. 1 Utilization of Numerical Results 104 106 110 113 115 116 VI EXPERIMENTAL EQUIPMENT DESIGN 121 6. 1 INTRODUCTION 6. 2 ELECTRICAL POWER SOURCE 6. 3 ELECTRICAL RESISTIVITY CONE PENETROMETER 6. 4...
NUMERICAL SIMULATION OF POOL BOILING FOR STEADY STATE AND TRANSIENT HEATING
Maruyama, Shigeo
1 NUMERICAL SIMULATION OF POOL BOILING FOR STEADY STATE AND TRANSIENT HEATING Ying He, Masahiro role in nucleate and transition boiling heat transfer at high heat flux. Many experiments have been in the numerical simulation of boiling heat transfer. In this study, based on the macrolayer evaporation model
Mahesh, Krishnan
Upstream entrainment in numerical simulations of spatially evolving round jets Pradeep C. Babu) Direct numerical simulation is used to study the effect of entrainment near the inflow nozzle on spatially evolving round jets. Inflow entrainment is obtained by providing a buffer region upstream
DIAGNOSIS OF INSULATED BUILDING WALLS USING PASSIVE INFRARED THERMOGRAPHY AND NUMERICAL SIMULATIONS
Paris-Sud XI, Université de
DIAGNOSIS OF INSULATED BUILDING WALLS USING PASSIVE INFRARED THERMOGRAPHY AND NUMERICAL SIMULATIONS This work presents the thermal monitoring of a multi-layered wall of a restored building (PANISSE platform parameters. Then they are compared with thermocouple measurements and numerical simulations. KEYWORDS
Numerical simulation of flow and mixing behavior of solids on a moving grate combustion system
Columbia University
Numerical simulation of flow and mixing behavior of solids on a moving grate combustion system by #12;ii Numerical simulation of flow and mixing behavior of solids on a moving grate combustion system, and to a large extent influences the combustion process. Municipal solid waste (MSW) is not a uniform fuel
The matching of 3D Rolie-Poly viscoelastic numerical simulations with experimental polymer melt flow
Jimack, Peter
Kingdom J. Embery and D. Auhl IRC in Polymer Science and Technology, Department of Physics and AstronomyThe matching of 3D Rolie-Poly viscoelastic numerical simulations with experimental polymer melt of commercial viscoelastic polymer melts. Numerical simulation techniques have steadily advanced over the last
Field Survey and Numerical Simulations: A Review of the 1998 Papua New Guinea Tsunami
Lynett, Patrick
Field Survey and Numerical Simulations: A Review of the 1998 Papua New Guinea Tsunami PATRICK J (PNG) tsunami of 1998 is re-examined through a detailed review of the field survey as well as numerous of frequency dispersion on the landslide-generated tsunami. The numerical comparisons indicate that the NLSW
Numerical simulations of mine penetration in soft sediments
Yao, Zhigang
2003-01-01T23:59:59.000Z
This study is concerned with developing a predictive model for depth of penetration of mines in soft sediments. The primary objective of this numerical study is to model soil resistance as a function of penetration depth using the finite element...
Numerical Simulations of Gamma-Ray Burst Explosions
Lazzati, Davide; López-Cámara, Diego
2015-01-01T23:59:59.000Z
Gamma-ray bursts are a complex, non-linear system that evolves very rapidly through stages of vastly different conditions. They evolve from scales of few hundred kilometers where they are very dense and hot to cold and tenuous on scales of parsecs. As such, our understanding of such a phenomenon can truly increase by combining theoretical and numerical studies adopting different numerical techniques to face different problems and deal with diverse conditions. In this review, we will describe the tremendous advancement in our comprehension of the bursts phenomenology through numerical modeling. Though we will discuss studies mainly based on jet dynamics across the progenitor star and the interstellar medium, we will also touch upon other problems such as the jet launching, its acceleration, and the radiation mechanisms. Finally, we will describe how combining numerical results with observations from Swift and other instruments resulted in true understanding of the bursts phenomenon and the challenges still lyi...
Numerical simulation of flow separation control by oscillatory fluid injection
Resendiz Rosas, Celerino
2005-08-29T23:59:59.000Z
and Lomax. The application of synthetic jet actuators is based in their ability to energize the boundary layer, thereby providing signifcant increase in the lift coefficient. This has been corroborated experimentally and it is corroborated numerically...
Numerical simulations of supercell interactions with thermal boundaries
Kay, Michael Paul
1999-01-01T23:59:59.000Z
to examine the effects of the interaction of simulated supercede thunderstorms with thermal boundaries on storm morphology and low-level rotation. This study differs from previous supercede modeling studies that use homogeneous initial conditions. A non...
Simulation of the secondary settling process with reliable numerical methods
Bürger, Raimund
are placed in alphabetical order Abstract A consistent model for the settling-compression-dispersion process The sedimentation process in the secondary settling tank (SST) is still a challenge in modelling the full Sedimentation, clarifier, conservation law, partial differential equation, numerical flux INTRODUCTION
NUMERICAL SIMULATIONS OF ROTATING SUNSPOTS G. J. J. Botha1
Rucklidge, Alastair
, at a depth of 0 to 5 Mm there exist subsurface horizontal vortical flows, while there are also suggestions's convection zone. The solution forms a central flux tube in the cylindrical numerical domain, with convection, vortical flow. As a result, the azimuthal velocity and mag- netic field have their maximum values close
Ravago Bastardo, Delmira Cristina
2005-08-29T23:59:59.000Z
The main objective of this research is to compare the performance of cyclic steam injection using horizontal wells based on the analytical model developed by Gunadi against that based on numerical simulation. For comparison, ...
Mass and charge flow in nanopores: numerical simulation via mesoscale models
Cecconi, Fabio
Mass and charge flow in nanopores: numerical simulation via mesoscale models Mauro Chinappi1 at nanoscale is here addressed via a recent developed mesoscale approach. In particular the flow
Ko, Min Seok
2009-05-15T23:59:59.000Z
This dissertation presents a numerical simulation of three-dimensional flow and heat transfer in a channel with a backward-facing step. Flow was considered to be steady, incompressible, and laminar. The flow medium was treated to be radiatively...
Roy, Subrata
1 American Institute of Aeronautics and Astronautics Numerical Simulation of a Gas Turbine of combustion by using nanosecond pulsed plasma actuators for a gas turbine combustor. Moreau [2] and Corke et
Numerical simulations of ion transport membrane oxy-fuel reactors for CO? capture applications
Hong, Jongsup
2013-01-01T23:59:59.000Z
Numerical simulations were performed to investigate the key features of oxygen permeation and hydrocarbon conversion in ion transport membrane (ITM) reactors. ITM reactors have been suggested as a novel technology to enable ...
Course MA59800: Numerical Simulation in Applied Geophysics. From the Mesoscale to the Macroscale.
Santos, Juan
Course MA59800: Numerical Simulation in Applied Geophysics. From the Mesoscale to the Macroscale matrix properties, fine layering, frac- tures and craks at the mesoscale (on the order of centimeters
Course: Numerical Simulation in Applied Geophysics. From the Mesoscale to the Macroscale
Santos, Juan
Course: Numerical Simulation in Applied Geophysics. From the Mesoscale to the Macroscale Professor variations in the fluid and solid matrix properties, fine layering, frac- tures and craks at the mesoscale
Numerical Simulation of Groundwater Withdrawal at the Nevada Test Site
Carroll, Rosemary; Giroux, Brian; Pohll, Greg; Hershey, Ronald; Russell, Charles; Howcroft, William
2004-01-28T23:59:59.000Z
Alternative uses of the Nevada Test Site (NTS) may require large amounts of water to construct and/or operate. The only abundant source of water at the NTS is groundwater. This report describes preliminary modeling to quantify the amount of groundwater available for development from three hydrographic areas at the NTS. Modeling was conducted with a three-dimensional transient numerical groundwater flow model.
Lang, Richard Anthony
2004-09-30T23:59:59.000Z
NUMERICAL SIMULATION OF COMMINUTION IN GRANULAR MATERIALS WITH AN APPLICATION TO FAULT GOUGE EVOLUTION A Thesis by RICHARD ANTHONY LANG Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE May 2002 Major Subject: Geophysics NUMERICAL SIMULATION OF COMMINUTION IN GRANULAR MATERIALS WITH AN APPLICATION TO FAULT GOUGE EVOLUTION A Thesis by RICHARD ANTHONY LANG Submitted...
Numerical Simulation of the Hydrodynamical Combustion to Strange Quark Matter
Brian Niebergal; Rachid Ouyed; Prashanth Jaikumar
2010-08-27T23:59:59.000Z
We present results from a numerical solution to the burning of neutron matter inside a cold neutron star into stable (u,d,s) quark matter. Our method solves hydrodynamical flow equations in 1D with neutrino emission from weak equilibrating reactions, and strange quark diffusion across the burning front. We also include entropy change due to heat released in forming the stable quark phase. Our numerical results suggest burning front laminar speeds of 0.002-0.04 times the speed of light, much faster than previous estimates derived using only a reactive-diffusive description. Analytic solutions to hydrodynamical jump conditions with a temperature dependent equation of state agree very well with our numerical findings for fluid velocities. The most important effect of neutrino cooling is that the conversion front stalls at lower density (below approximately 2 times saturation density). In a 2-dimensional setting, such rapid speeds and neutrino cooling may allow for a flame wrinkle instability to develop, possibly leading to detonation.
Numerical simulation of copper ablation by ultrashort laser pulses
Ding, PengJi; Li, YuHong
2011-01-01T23:59:59.000Z
Using a modified self-consistent one-dimensional hydrodynamic lagrangian fluid code, laser ablation of solid copper by ultrashort laser pulses in vacuum was simulated to study fundamental mechanisms and to provide a guide for drilling periodic microholes or microgratings on the metal surface. The simulated laser ablation threshold is a approximate constancy in femtosecond regime and increases as the square root of pulse duration in picosecond regime. The ablation depth as a function of pulse duration shows four different regimes and a minimum for a pulse duration of ~ 12ps for various laser fluences. The influence of laser-induced plasma shielding on ablation depth is also studied.
Ismagilov, Rustem F.
Effects of Shear Rate on Propagation of Blood Clotting Determined Using Microfluidics and Numerical-ismagilov@uchicago.edu Abstract: This paper describes microfluidic experiments with human blood plasma and numerical simulations removed. In addition, these results demonstrate the utility of simplified mechanisms and microfluidics
Kirby, James T.
Numerical simulation of the 2011 Tohoku tsunami: Comparison with field observations and sensitivity history, created a major tsunami that caused numerous deaths and enormous destruction on the nearby Hon- shu coast. Various tsunami sources were developed for this event, based on inverting seismic or GPS
Numerical Investigation of a Transverse Jet in a Supersonic Crossflow using Large Eddy Simulation
Paris-Sud XI, Université de
Numerical Investigation of a Transverse Jet in a Supersonic Crossflow using Large Eddy Simulation injected fuel jets in hot supersonic crossflows. This paper describes the numerical algorithm being used into a supersonic crossflow computed on a coarse mesh. These results are discussed and similarity
Numerical Simulation of Pulse-Tube Refrigerators: 1D model I.A. Lyulina1
Eindhoven, Technische Universiteit
of a piston, an aftercooler (AC), a regenerator, a cold heat exchanger (CHX), a tube, a hot heat exchanger numerical model has been introduced to study steady oscillatory heat and mass transfer in the tube section, numerical simulation, high resolution scheme 1 Introduction The pulse tube is a relatively new type
A Simulation and Decision Framework for Selection of Numerical Solvers in Scientific Computing
Burns, Peter
A Simulation and Decision Framework for Selection of Numerical Solvers in Scientific Computing by the journal ACM Transactions On Mathematical Software (ACM 2004 [1]) and the Numerical Recipes published Peter Bunus Department of Computer and Information Science Linköping University, Sweden petbu
Physical formulation and numerical algorithm for simulating N ...
S. Dong
2014-12-15T23:59:59.000Z
Dec 5, 2014 ... Center for Computational and Applied Mathematics, Department of ... form enables one to compute the N-phase mixing energy density coefficients in an .... provides an efficient method for simulating N-phase flows, which has also overcome ...... three categories: (i) input parameters or data, (ii) independent ...
Numerical simulation of tropical cumulus congestus during TOGA COARE
Mechem, David B.
2013-09-17T23:59:59.000Z
and active phases of the intraseasonal oscillation (ISO), with a unique signature consistent with cloudy-air detrainment near the 0°C isotherm. Congestus clouds in the simulation contribute 34% of the total precipitation during a 10 day transition period from...
A numerical simulation of slantwise convection: its structure and evolution
Overpeck, Scott Allen
2001-01-01T23:59:59.000Z
convection), and could be a possible explanation for frontal rainbands. This study uses the Penn State/NCAR Mesoscale Model (MM5) as a diagnostic tool to simulate a slantwise convective case from the Genesis of Atlantic Lows Experiment (GALE, Dirks et al...
Numerical simulation of three-dimensional electrical flow through geomaterials
Akhtar, Anwar Saeed
1998-01-01T23:59:59.000Z
investigation results further validate this fact. DEDICATION To my parents, who desired it more for me than I did, and to my dearest wife Sofia and loving daughter Aneeka, who endured most of it. ACKNOWLEDGMENTS The author would like to express his... 46 46 50 50 50 51 52 53 54 57 57 58 59 60 62 64 65 67 70 CHAPTER IV ELECTRICAL FLOW THROUGH GEOMATERIALS WITH ELECTRODES AT GROUND SURFACE Page 73 4. 1 INTRODUCTION 4. 2 NUMERICAL INVESTIGATION OF ELECTRICAL FLOW THROUGH...
Numerical simulation of optical feedback on a quantum dot lasers
Al-Khursan, Amin H., E-mail: ameen_2all@yahoo.com [Thi-Qar University, Nassiriya Nanotechnology Research Laboratory (NNRL), Science College (Iraq); Ghalib, Basim Abdullattif [Babylon University, Laser Physics Department, Science College for Women (Iraq); Al-Obaidi, Sabri J. [Al-Mustansiriyah University, Physics Department, Science College (Iraq)
2012-02-15T23:59:59.000Z
We use multi-population rate equations model to study feedback oscillations in the quantum dot laser. This model takes into account all peculiar characteristics in the quantum dots such as inhomogeneous broadening of the gain spectrum, the presence of the excited states on the quantum dot and the non-confined states due to the presence of wetting layer and the barrier. The contribution of quantum dot groups, which cannot follow by other models, is simulated. The results obtained from this model show the feedback oscillations, the periodic oscillations which evolves to chaos at higher injection current of higher feedback levels. The frequency fluctuation is attributed mainly to wetting layer with a considerable contribution from excited states. The simulation shows that is must be not using simple rate equation models to express quantum dots working at excited state transition.
Numerical simulation of survey misalignment effects in the ATA structure
Close, E.R.
1981-02-01T23:59:59.000Z
A computer program MSALIGN incorporating solenoidal magnet positioning errors, survey alignment errors, and structure support sag has been written and used to simulate the Advanced Test Accelerator (ATA) inorder to investigate the effects of errors on the transported beam. Runs using up to 10K particles to represent the beam were made over ensembles of up to 100 misaligned machines. They show that for the ATA design tolerances the resultant beam steering is acceptable and easily corrected using steering magnets. Also, that for changes within a factor of 2 to 3 over design values the variation is linear. The program MSALIGN is general in design. Given the appropriate misalignment procedure it can simulate other machines or study other types of errors.
NUMERICAL SIMULATIONS OF LONG TERM UNSATURATED FLOW AND ACID MINE DRAINAGE AT WASTE ROCK PILES
Aubertin, Michel
NUMERICAL SIMULATIONS OF LONG TERM UNSATURATED FLOW AND ACID MINE DRAINAGE AT WASTE ROCK PILES Omar representative) waste rock piles and using observed climatic recharge data. The simulations were used to help are applied each year at the top of the piles, the water content profiles become periodic after a few years
OTC 23597-MS Numerical Simulation of Floating Offshore Wind Turbines Including Aero-
Sweetman, Bert
OTC 23597-MS Numerical Simulation of Floating Offshore Wind Turbines Including Aero- Elasticity methodology is presented for simulation of dynamic behavior of floating offshore wind turbines. Wind forces. Introduction and Background The economic potential of offshore deep water wind turbines has not yet been fully
R. Volk; E. Calzavarini; G. Verhille; D. Lohse; N. Mordant; J. -F. Pinton; F. Toschi
2007-10-17T23:59:59.000Z
We compare experimental data and numerical simulations for the dynamics of inertial particles with finite density in turbulence. In the experiment, bubbles and solid particles are optically tracked in a turbulent flow of water using an Extended Laser Doppler Velocimetry technique. The probability density functions (PDF) of particle accelerations and their auto-correlation in time are computed. Numerical results are obtained from a direct numerical simulation in which a suspension of passive pointwise particles is tracked, with the same finite density and the same response time as in the experiment. We observe a good agreement for both the variance of acceleration and the autocorrelation timescale of the dynamics; small discrepancies on the shape of the acceleration PDF are observed. We discuss the effects induced by the finite size of the particles, not taken into account in the present numerical simulations.
Numerical simulation of laminar reacting flows with complex chemistry
Day, Marcus S.; Bell, John B.
1999-12-01T23:59:59.000Z
We present an adaptive algorithm for low Mach number reacting flows with complex chemistry. Our approach uses a form of the low Mach number equations that discretely conserves both mass and energy. The discretization methodology is based on a robust projection formulation that accommodates large density contrasts. The algorithm uses an operator-split treatment of stiff reaction terms and includes effects of differential diffusion. The basic computational approach is embedded in an adaptive projection framework that uses structured hierarchical grids with subcycling in time that preserves the discrete conservation properties of the underlying single-grid algorithm. We present numerical examples illustrating the performance of the method on both premixed and non-premixed flames.
Numerical Simulations of Leakage from Underground LPG Storage Caverns
Yamamoto, Hajime; Pruess, Karsten
2004-09-01T23:59:59.000Z
To secure a stable supply of petroleum gas, underground storage caverns for liquified petroleum gas (LPG) are commonly used in many countries worldwide. Storing LPG in underground caverns requires that the surrounding rock mass remain saturated with groundwater and that the water pressure be higher than the liquid pressure inside the cavern. In previous studies, gas containment criteria for underground gas storage based on hydraulic gradient and pressure have been discussed, but these studies do not consider the physicochemical characteristics and behavior of LPG such as vaporization and dissolution in groundwater. Therefore, while these studies are very useful for designing storage caverns, they do not provide better understanding of the either the environmental effects of gas contamination or the behavior of vaporized LPG. In this study, we have performed three-phase fluid flow simulations of gas leakage from underground LPG storage caverns, using the multiphase multicomponent nonisothermal simulator TMVOC (Pruess and Battistelli, 2002), which is capable of solving the three-phase nonisothermal flow of water, gas, and a multicomponent mixture of volatile organic chemicals (VOCs) in multidimensional heterogeneous porous media. A two-dimensional cross-sectional model resembling an actual underground LPG facility in Japan was developed, and gas leakage phenomena were simulated for three different permeability models: (1) a homogeneous model, (2) a single-fault model, and (3) a heterogeneous model. In addition, the behavior of stored LPG was studied for the special case of a water curtain suddenly losing its function because of operational problems, or because of long-term effects such as clogging of boreholes. The results of the study indicate the following: (1) The water curtain system is a very powerful means for preventing gas leakage from underground storage facilities. By operating with appropriate pressure and layout, gas containment can be ensured. (2) However , in highly heterogeneous media such as fractured rock and fault zones, local flow paths within which the gas containment criterion is not satisfied could be formed. To eliminate such zones, treatments such as pre/post grouting or an additional installment of water-curtain boreholes are essential. (3) Along highly conductive features such as faults, even partially saturated zones possess certain effects that can retard or prevent gas leakage, while a fully unsaturated fault connected to the storage cavern can quickly cause a gas blowout. This possibility strongly suggests that ensuring water saturation of the rock surrounding the cavern is a very important requirement. (4) Even if an accident should suddenly impair the water curtain, the gas plume does not quickly penetrate the ground surface. In these simulations, the plume takes several months to reach the ground surface.
Evaluation of Residential Hot Water Distribution Ssytems by Numeric Simulation
Wendt, ROBERT
2005-08-17T23:59:59.000Z
The objective of this project was to evaluate the performance and economics of various domestic hot water distribution systems in representative California residences. While the greatest opportunities for improved efficiency occur in new construction, significant improvements can also be made in some existing distribution systems. Specific objectives of the project tasks were: (1) Simulate potential energy savings of, perform cost-benefit analyses of, and identify market barriers to alternative new systems. (2) Simulate potential energy savings of, perform cost-benefit analyses of, and identify market barriers to maintenance, repair, and retrofit modifications of existing systems. (3) Evaluate potential impact of adopting alternative hot water distribution systems and report project findings. The outcome of this project is to provide homeowners, homebuilders, systems suppliers, municipal code officials and utility providers (both electric and water/sewer) with a neutral, independent, third party, cost-benefit analysis of alternative hot water distribution systems for use in California. The results will enable these stakeholders to make informed decisions regarding which system is most appropriate for use.
On the relevance of numerical simulations to booming sand
Patrick Richard; Sean Mcnamara; Merline Tankeo
2012-01-04T23:59:59.000Z
We have performed a simulation study of 3D cohesionless granular flows down an inclined chute. We find that the oscillations observed in [L.E. Silbert, Phys. Rev. Lett., 94, 098002 (2005)] near the angle of repose are harmonic vibrations of the lowest normal mode. Their frequencies depend on the contact stiffness as well as on the depth of the flow. Could these oscillations account for the phenomena of "booming sand"? We estimate an effective contact stiffness from the Hertz law, but this leads to frequencies several times higher than observed. However, the Hertz law also predicts interpenetrations of a few nanometers, indicating that the oscillations frequencies are governed by the surface stiffness, which can be much lower than the bulk one. This is in agreement with previous studies ascribing the ability to sing to the presence of a soft coating on the grain surface.
On numerical turbulence generation for test-particle simulations
Tautz, R. C. [Zentrum fuer Astronomie und Astrophysik, Technische Universitaet Berlin, Hardenbergstrasse 36, D-10623 Berlin (Germany); Dosch, A. [Center for Space Plasmas and Aeronomic Research, University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, Alabama 35805 (United States)
2013-02-15T23:59:59.000Z
A modified method is presented to generate artificial magnetic turbulence that is used for test-particle simulations. Such turbulent fields are obtained from the superposition of a set of wave modes with random polarizations and random directions of propagation. First, it is shown that the new method simultaneously fulfils requirements of isotropy, equal mean amplitude and variance for all field components, and vanishing divergence. Second, the number of wave modes required for a stochastic particle behavior is investigated by using a Lyapunov approach. For the special case of slab turbulence, it is shown that already for 16 wave modes the particle behavior agrees with that shown for considerably larger numbers of wave modes.
Numerical simulations of X-rays Free Electron Lasers (XFEL)
Paolo Antonelli; Agissilaos Athanassoulis; Zhongyi Huang; Peter A. Markowich
2014-06-17T23:59:59.000Z
We study a nonlinear Schr\\"odinger equation which arises as an effective single particle model in X-ray Free Electron Lasers (XFEL). This equation appears as a first-principles model for the beam-matter interactions that would take place in an XFEL molecular imaging experiment in \\cite{frat1}. Since XFEL is more powerful by several orders of magnitude than more conventional lasers, the systematic investigation of many of the standard assumptions and approximations has attracted increased attention. In this model the electrons move under a rapidly oscillating electromagnetic field, and the convergence of the problem to an effective time-averaged one is examined. We use an operator splitting pseudo-spectral method to investigate numerically the behaviour of the model versus its time-averaged version in complex situations, namely the energy subcritical/mass supercritical case, and in the presence of a periodic lattice. We find the time averaged model to be an effective approximation, even close to blowup, for fast enough oscillations of the external field. This work extends previous analytical results for simpler cases \\cite{xfel1}.
The Numerical Simulation Of A Transitional Flow In The VKI-GENOA Turbine Cascade
Yershov, Sergiy; Yakovlev, Viktor; Gryzun, Maria
2015-01-01T23:59:59.000Z
This study presents a numerical simulation of a 3D viscous flow in the VKI-Genoa cascade that takes into account the laminar-turbulent transition. The numerical simulation is performed using the Reynolds-averaged Navier-Stokes equations and the two-equation k-omega SST turbulence model. The algebraic Production Term Modification model is used for modeling the laminar-turbulent transition. Computations of both fully turbulent and transitional flows are carried out. The contours of the Mach number, the turbulence kinetic energy, the entropy function, as well as limiting streamlines are presented. The analysis of the numerical results demonstrates the influence of the laminar-turbulent transition on the secondary flow pattern. The comparison between the present computational results and the existing experimental and numerical data shows that the proposed approach reflects sufficiently the physics of the laminar-turbulent transition in turbine cascades.
The ignition process in type Ia supernovae: numerical simulations of core temperature perturbations
L. Iapichino; M. Brüggen; W. Hillebrandt; J. C. Niemeyer
2007-11-13T23:59:59.000Z
The onset of the thermonuclear runaway in a Chandrasekhar-mass white dwarf, leading to the explosion as a type Ia supernova, is studied with hydrodynamical simulations. We investigate the evolution of temperature fluctuations (``bubbles'') in the WD's convective core by means of 2D numerical simulations. We show how the occurrence of the thermonuclear runaway depends on various bubble parameters. The relevance of the progenitor's composition for the ignition process is also discussed.
The ignition process in type Ia supernovae: numerical simulations of core temperature perturbations
Iapichino, L; Hillebrandt, W; Niemeyer, J C
2007-01-01T23:59:59.000Z
The onset of the thermonuclear runaway in a Chandrasekhar-mass white dwarf, leading to the explosion as a type Ia supernova, is studied with hydrodynamical simulations. We investigate the evolution of temperature fluctuations (``bubbles'') in the WD's convective core by means of 2D numerical simulations. We show how the occurrence of the thermonuclear runaway depends on various bubble parameters. The relevance of the progenitor's composition for the ignition process is also discussed.
Numerical simulation of air/water multiphase flows for ceramic sanitary ware design by multiple GPUs
8 Numerical simulation of air/water multiphase flows for ceramic sanitary ware design by multiple and manufacturing of plumbing products such as ceramic sanitary wares. In order to re-produce the complex/water multiphase flows for ceramic sanitary ware design by multiple GPUs Being a world-wide leading company, TOTO
Numerical methods for the simulation of a corrosion model in a nuclear waste deep repository $
Paris-Sud XI, Université de
Numerical methods for the simulation of a corrosion model in a nuclear waste deep repository $ C of the French nuclear waste management agency ANDRA, investigations are conducted to optimize and finalize by the Nuclear Waste Management Agency ANDRA Corresponding author. Phone: +49 30 20372 560, Fax: +49 30 2044975
Numerical Simulations Reveal the Origin of QPOs in Black Hole Candidates
Sandip K. Chakrabarti
2005-01-14T23:59:59.000Z
We present results of various types of numerical simulations of black hole accretion disks and find that those flows which are relatively non-dissipative and which contain accretion shocks are the best candidates so far. The power density spectra (PDS) reveal the aspects which are similar to what are observed in black hole candidates.
PHYSICS OF FLUIDS 24, 103306 (2012) Numerical simulation of turbulent sediment transport,
Claudin, Philippe
2012-01-01T23:59:59.000Z
PHYSICS OF FLUIDS 24, 103306 (2012) Numerical simulation of turbulent sediment transport, from bed October 2012) Sediment transport is studied as a function of the grain to fluid density ratio using two of the static bed, and is called bed load. Steady, or "saturated" transport is reached when the fluid borne
Numerical Simulation of a Single-Wafer Isothermal Plasma Etching Reactor
Economou, Demetre J.
Numerical Simulation of a Single-Wafer Isothermal Plasma Etching Reactor Sang-Kyu Parkand Demetre J-plate single- wafer isothermal reactor was conducted. The oxygen plasma etching of polymer under high pressure with emphasis on chemical etching. Etching rate and uniformity were examined as a function of reactor geometry
Harting, Jens
EulerianEulerian two-phase numerical simulation of nanofluid laminar forced convection August 2010 Accepted 5 August 2010 Keywords: Nanofluid Microchannel Two-phase Laminar Heat transfer a b s t r a c t In this paper, laminar forced convection heat transfer of a copperwater nanofluid inside
Numerical simulation of detonation processes in a variable cross-section chamber
Texas at Arlington, University of
in a combustion chamber with variable cross- sections are numerically simulated for a hydrogenair reacting flow facilities [2]. The pri- mary advantage of detonation combustion as com- pared to deflagration is its rapid energy release. This rapid energy release allows the design of pulse detona- tion engines with high
American Institute of Aeronautics and Astronautics Numerical Simulation of Detonation Processes in a
Texas at Arlington, University of
The detonation processes occurring in a combustion chamber with variable cross-sections are numerically simulated, such as in propulsion1 and in high-enthalpy ground test facilities. 2 The primary advantage of detonation combustion as compared to deflagration is its rapid energy release. This rapid energy release allows the design of pulse
Numerical methods for the simulation of salt migration in regional groundwater
Vuik, Kees
Numerical methods for the simulation of salt migration in regional groundwater flow E.S. van Baaren . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.2.3 Groundwater flow equation . . . . . . . . . . . . . . . . . 10 2.3 Solute transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 3.2.2 Groundwater equation . . . . . . . . . . . . . . . . . . . . 20 3.2.3 Solute transport
NUMERICAL METHODS FOR THE SIMULATION OF CONTINUOUS SEDIMENTATION IN IDEAL CLARIFIER-THICKENER UNITS
a model of continuous sedimentation of ideal suspensions of small solid particles dispersed in a viscous of Kynch's and related sedimentation models are provided by Bustos et al. (1999) and Burger and WendlandNUMERICAL METHODS FOR THE SIMULATION OF CONTINUOUS SEDIMENTATION IN IDEAL CLARIFIER-THICKENER UNITS
Numeric Simulation of Heat Transfer and Electrokinetic Flow in an Electroosmosis-Based
Le Roy, Robert J.
Numeric Simulation of Heat Transfer and Electrokinetic Flow in an Electroosmosis-Based Continuous is dedicated to under- standing the fluid flow and heat transfer mechanisms occurring in continuous flow PCR are discussed in detail. The importance of each heat transfer mechanism for different situations is also
Direct numerical simulation of turbulent heat transfer in annuli: effect of heat flux ratio.
Paris-Sud XI, Université de
Direct numerical simulation of turbulent heat transfer in annuli: effect of heat flux ratio. M-la-Vall´ee cedex 2, France (Dated: October 23, 2008) Abstract Fully developed turbulent flow and heat transfer square (rms) of temperature fluctuations, turbulent heat fluxes, heat transfer, ...). To validate
Steam generators two phase flows numerical simulation with liquid and gas momentum equations
Paris-Sud XI, Université de
. The secondary flow is another loop that links the steam generator and the turbines. Inside the exchangerSteam generators two phase flows numerical simulation with liquid and gas momentum equations M Abstract This work takes place in steam generators flow studies and we consider here steady state three
Stochastic numerical simulations of long term unsaturated flow in waste rock piles
Aubertin, Michel
Stochastic numerical simulations of long term unsaturated flow in waste rock piles O. Fala Genivar water flow in waste rock piles using selected realizations of stochastically distributed hydraulic term hydrogeological behaviour of waste rock piles, to help select the construction sequence
Timbie, Peter
, which is crucial to minimize stray magnetic fields that could interfere with other refrigerator stagesOptimization and Numerical Simulation of the Cycling Process and Magnetic Shielding of a Miniature Adiabatic Demagnetization Refrigerator Benjamin M. Cain May 18, 2004 A Senior Honors Thesis Project Under
Numerical simulation of a thermoacoustic couple A. I. Abd El-Rahmana
Paris-Sud XI, Université de
Numerical simulation of a thermoacoustic couple A. I. Abd El-Rahmana and E. Abdel-filled half-wavelength thermoacoustic refrigerator. The finite volume method is used, and the solid and air in thermoacoustic refrigerators, characterizing and optimizing their performance, and building models
Numerical Simulation of a Molten Carbonate Fuel Cell by Partial Differential Algebraic
Schittkowski, Klaus
Numerical Simulation of a Molten Carbonate Fuel Cell by Partial Differential Algebraic Equations K. The dynamical behavior of a molten carbonate fuel cell (MCFC) can be modeled by systems of partial differential-algebraic equations is subsequently integrated by an implicit DAE solver. 1 Introduction Molten carbonate fuel cells
Numerical simulations of radon as an in situ partitioning tracer for quantifying NAPL
Semprini, Lewis
Numerical simulations of radon as an in situ partitioning tracer for quantifying NAPL contaminationpull partitioning tracer tests using radon-222 to quantify non- aqueous phase liquid contamination. J. Contam. Hydrol. 58, 129146] of pushpull tests using radon as a naturally occurring partitioning tracer
A MultiLevel Preconditioner with Applications to the Numerical Simulation of Coating Problems
Zhang, Jun
from a rotating roll (BKNIFE01 matrix). A very important problem in coating process is to produce between two walls (PDF1 matrix). Roll Air Air Blade Liquid Pan Figure 2: The knife coating model, a bladeA MultiLevel Preconditioner with Applications to the Numerical Simulation of Coating Problems
Numerical Simulation of the December 26, 2004 Indian Ocean Tsunami using a Boussinesq model
Kirby, James T.
tsunami education or tsunami warning system in the re- gion exaccerbated the number of fatalities, even. Scientists had been warning of the growing exposure of coastal residents to tsunami hazards for yearsNumerical Simulation of the December 26, 2004 Indian Ocean Tsunami using a Boussinesq model Philip
Kochevsky, A N
2005-01-01T23:59:59.000Z
The paper describes capabilities of numerical simulation of liquid flows with solid and/or gas admixtures in centrifugal pumps using modern commercial CFD software packages, with the purpose to predict performance curves of the pumps treating such media. In particular, the approaches and multiphase flow models available in the package CFX-5 are described; their advantages and disadvantages are analyzed.
Wang, Yuqing
Energy Production, Frictional Dissipation, and Maximum Intensity of a Numerically Simulated is eventually dissipated due to surface friction. Since the energy production rate is a linear function while frictional dissipation rate balances the energy production rate near the radius of maximum wind (RMW
Wang, Yuqing
0 Energy Production, Frictional Dissipation, and Maximum Intensity of a Numerically Simulated is eventually dissipated due to surface friction. Since the energy production rate is a linear function while frictional dissipation rate balances the energy production rate near the radius of maximum wind (RMW
Numerical Simulations of the Wave Bottom Boundary Layer over Sand Ripples
Slinn, Donald
locations. Under conditions of oscillatory potential flow external to the boundary layer causedNumerical Simulations of the Wave Bottom Boundary Layer over Sand Ripples by Thomas Pierro A Thesis boundary layer are believed to play a major role in the re-suspension and transport of sediment, as well
Schlegel, H. Bernhard
A Numerical Simulation of Nonadiabatic Electron Excitation in the Strong Field Regime: Linear of the electronic optical response of a series of linear polyenes in strong laser fields. Ethylene, butadiene and 760 nm. Time evolution of the electron population indicates not only the electrons, but also lower
Towards Numerical Simulation of Cavitating Flows in Complex M. Mattson and K. Mahesh
Mahesh, Krishnan
Towards Numerical Simulation of Cavitating Flows in Complex Geometries M. Mattson and K. Mahesh (Aerospace Engineering and Mechanics, University of Minnesota) 27th Symposium on Naval Hydrodynamics Seoul of bubbles in complex geometries, with specific applica- tion to modeling cavitation instabilities
Numerical Simulation of Mesoscale Circulations in a Region of Contrasting Soil Types
Raman, Sethu
Numerical Simulation of Mesoscale Circulations in a Region of Contrasting Soil Types SETHU RAMAN,1 AARON SIMS,1,2 ROBB ELLIS,1 and RYAN BOYLES 1 Abstract--Mesoscale processes that form due to changes on mesoscale processes are examined. Climatological analyses indicate increased convective precipitation
McKenzie, Jeffrey M.
Groundwater flow with energy transport and waterice phase change: Numerical simulations saturated, coupled porewater-energy transport, with freezing and melting porewater, and includes propor for groundwater and energy transport with ice formation and melting are proposed that may be used by other
Numerical Simulation of Phase Transformations in Shape Memory Alloy Thin Films
Melnik, Roderick
Numerical Simulation of Phase Transformations in Shape Memory Alloy Thin Films Debiprosad Roy- tions of phase transformation dynamics in shape memory alloy thin films are reported in this paper transformation path from austenite to martensites and recovers the original shape. This is known as shape memory
Numerical simulations of multi-shell plasma twisters in the solar atmosphere
Murawski, K; Musielak, Z E; Dwivedi, B N
2015-01-01T23:59:59.000Z
We perform numerical simulations of impulsively generated Alfv\\'en waves in an isolated photospheric flux tube, and explore the propagation of these waves along such magnetic structure that extends from the photosphere, where these waves are triggered, to the solar corona, and analyze resulting magnetic shells. Our model of the solar atmosphere is constructed by adopting the temperature distribution based on the semi-empirical model and specifying the curved magnetic field lines that constitute the magnetic flux tube which is rooted in the solar photosphere. The evolution of the solar atmosphere is described by 3D, ideal magnetohydrodynamic equations that are numerically solved by the FLASH code. Our numerical simulations reveal, based on the physical properties of the multi-shell magnetic twisters and the amount of energy and momentum associated with them, that these multi-shell magnetic twisters may be responsible for the observed heating of the lower solar corona and for the formation of solar wind. Moreov...
Numerical dissipation and the bottleneck effect in simulations of compressible isotropic turbulence
Schmidt, W; Niemeyer, J C
2004-01-01T23:59:59.000Z
Energy spectrum functions computed from data of various three-dimensional simulations of forced isotropic turbulence are investigated. The piece-wise parabolic method (PPM) was used to treat flows with Mach number of the order unity. The dissipation is of purely numerical origin. For the dimensionless mean rate of dissipation, we find values in agreement with results from other, mostly incompressible turbulence simulations. The so-called bottleneck phenomenon is also present in the turbulence energy spectra. Although the bottleneck reduces the range of nearly inertial scales considerably, we were able to estimate the value of the Kolmogorov constant. In the statistically stationary regime, $C\\approx 1.7$ for strictly subsonic turbulence, but also in the presence of shocklets in moderately transonic flows. As compressive components become more significant, however, the value of $C$ appears to decrease. Moreover, we discuss length scales related to numerical dissipation, in particular, an effective numerical le...
Sagert, I; Fattoyev, F J; Postnikov, S; Horowitz, C J
2015-01-01T23:59:59.000Z
Neutron star and supernova matter at densities just below the nuclear matter saturation density is expected to form a lattice of exotic shapes. These so-called nuclear pasta phases are caused by Coulomb frustration. Their elastic and transport properties are believed to play an important role for thermal and magnetic field evolution, rotation and oscillation of neutron stars. Furthermore, they can impact neutrino opacities in core-collapse supernovae. In this work, we present proof-of-principle 3D Skyrme Hartree-Fock (SHF) simulations of nuclear pasta with the Multi-resolution ADaptive Numerical Environment for Scientific Simulations (MADNESS). We perform benchmark studies of $^{16} \\mathrm{O}$, $^{208} \\mathrm{Pb}$ and $^{238} \\mathrm{U}$ nuclear ground states and calculate binding energies via 3D SHF simulations. Results are compared with experimentally measured binding energies as well as with theoretically predicted values from an established SHF code. The nuclear pasta simulation is initialized in the so...
Salpeter, Nathaniel
2012-07-16T23:59:59.000Z
-intrusive particle tracking velocimetry (PTV) techniques. The second experiment is of a simulated double ended guillotine break in the prismatic block gas cooled reactor. Numerical simulations of jet flow mixing in the lower plenum of a prismatic block high...
Analysis of the flamelet concept in the numerical simulation of laminar partially premixed flames
Consul, R.; Oliva, A.; Perez-Segarra, C.D.; Carbonell, D. [Centre Tecnologic de Transferencia de Calor (CTTC), Universitat Politecnica de Catalunya (UPC), Colom 11, E-08222, Terrassa, Barcelona (Spain); de Goey, L.P.H. [Eindhoven University of Technology, Department of Mechanical Engineering, P.O. Box 513, 5600 MB Eindhoven (Netherlands)
2008-04-15T23:59:59.000Z
The aim of this work is to analyze the application of flamelet models based on the mixture fraction variable and its dissipation rate to the numerical simulation of partially premixed flames. Although the main application of these models is the computation of turbulent flames, this work focuses on the performance of flamelet concept in laminar flame simulations removing, in this way, turbulence closure interactions. A well-known coflow methane/air laminar flame is selected. Five levels of premixing are taken into account from an equivalence ratio {phi}={infinity} (nonpremixed) to {phi}=2.464. Results obtained using the flamelet approaches are compared to data obtained from the detailed solution of the complete transport equations using primitive variables. Numerical simulations of a counterflow flame are also presented to support the discussion of the results. Special emphasis is given to the analysis of the scalar dissipation rate modeling. (author)
Numerical dissipation and the bottleneck effect in simulations of compressible isotropic turbulence
W. Schmidt; W. Hillebrandt; J. C. Niemeyer
2005-03-15T23:59:59.000Z
The piece-wise parabolic method (PPM) is applied to simulations of forced isotropic turbulence with Mach numbers $\\sim 0.1... 1$. The equation of state is dominated by the Fermi pressure of an electron-degenerate fluid. The dissipation in these simulations is of purely numerical origin. For the dimensionless mean rate of dissipation, we find values in agreement with known results from mostly incompressible turbulence simulations. The calculation of a Smagorinsky length corresponding to the rate of numerical dissipation supports the notion of the PPM supplying an implicit subgrid scale model. In the turbulence energy spectra of various flow realisations, we find the so-called bottleneck phenomenon, i.e., a flattening of the spectrum function near the wavenumber of maximal dissipation. The shape of the bottleneck peak in the compensated spectrum functions is comparable to what is found in turbulence simulations with hyperviscosity. Although the bottleneck effect reduces the range of nearly inertial length scales considerably, we are able to estimate the value of the Kolmogorov constant. For steady turbulence with a balance between energy injection and dissipation, it appears that $C\\approx 1.7$. However, a smaller value is found in the case of transonic turbulence with a large fraction of compressive components in the driving force. Moreover, we discuss length scales related to the dissipation, in particular, an effective numerical length scale $\\Delta_{\\mathrm{eff}}$, which can be regarded as the characteristic smoothing length of the implicit filter associated with the PPM.
Guidoboni, Giovanna
2007-01-01T23:59:59.000Z
J. Non-Newtonian Fluid Mech. 142 (2007) 36Â62 Review On the numerical simulation of Bingham visco-plastic various results and methods concerning the numerical simulation of Bingham visco-plastic flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 2. On the modeling of Bingham viscous plastic flow
Rutqvist, Jonny; Rutqvist, J.; Moridis, G.J.
2008-06-01T23:59:59.000Z
In this paper, we describe the development and application of a numerical simulator that analyzes the geomechanical performance of hydrate-bearing sediments, which may become an important future energy supply. The simulator is developed by coupling a robust numerical simulator of coupled fluid flow, hydrate thermodynamics, and phase behavior in geologic media (TOUGH+HYDRATE) with an established geomechanical code (FLAC3D). We demonstrate the current simulator capabilities and applicability for two examples of geomechanical responses of hydrate bearing sediments during production-induced hydrate dissociation. In these applications, the coupled geomechanical behavior within hydrate-bearing seducements are considered through a Mohr-Coulomb constitutive model, corrected for changes in pore-filling hydrate and ice content, based on laboratory data. The results demonstrate how depressurization-based gas production from oceanic hydrate deposits may lead to severe geomechanical problems unless care is taken in designing the production scheme. We conclude that the coupled simulator can be used to design production strategies for optimizing production, while avoiding damaging geomechanical problems.
Modelling and Numerical Simulation of Gas Migration in a Nuclear Waste Repository
Bourgeat, Alain; Smai, Farid
2010-01-01T23:59:59.000Z
We present a compositional compressible two-phase, liquid and gas, flow model for numerical simulations of hydrogen migration in deep geological radioactive waste repository. This model includes capillary effects and the gas diffusivity. The choice of the main variables in this model, Total or Dissolved Hydrogen Mass Concentration and Liquid Pressure, leads to a unique and consistent formulation of the gas phase appearance and disappearance. After introducing this model, we show computational evidences of its adequacy to simulate gas phase appearance and disappearance in different situations typical of underground radioactive waste repository.
Rossi, Tuomas P; Sakko, Arto; Puska, Martti J; Nieminen, Risto M
2015-01-01T23:59:59.000Z
We present an approach for generating local numerical basis sets of improving accuracy for first-principles nanoplasmonics simulations within time-dependent density functional theory. The method is demonstrated for copper, silver, and gold nanoparticles that are of experimental interest but computationally demanding due to the semi-core d-electrons that affect their plasmonic response. The basis sets are constructed by augmenting numerical atomic orbital basis sets by truncated Gaussian-type orbitals generated by the completeness-optimization scheme, which is applied to the photoabsorption spectra of homoatomic metal atom dimers. We obtain basis sets of improving accuracy up to the complete basis set limit and demonstrate that the performance of the basis sets transfers to simulations of larger nanoparticles and nanoalloys as well as to calculations with various exchange-correlation functionals. This work promotes the use of the local basis set approach of controllable accuracy in first-principles nanoplasmon...
Numerical Simulation of Breaking Waves Using Level-Set Navier-Stokes Method
Dong, Qian
2010-07-14T23:59:59.000Z
A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Hamn-Ching Chen Committee Members, Alan Palazzolo Jun Zhang Head of Department, John Niedzwecki May 2010... Major Subject: Civil Engineering iii ABSTRACT Numerical Simulation of Breaking Waves using Level-Set Navier-Stokes Method. (May 2010) Qian Dong, B.S., Zhejiang University Chair of Advisory Committee: Dr. Hamn-Ching Chen In the present study...
Numerical Simulation of Interaction of Hypervelocity Particle Stream with a Target
Lomov, I; Liu, B; Georgevich, V; Antoun, T
2007-07-31T23:59:59.000Z
We present results of direct numerical simulations of impact of hypervelocity particle stream with a target. The stream of interest consists of submillimeter (30-300 micron) brittle ceramic particles. Current supercomputer capabilities make it possible to simulate a realistic size of streams (up to 20 mm in diameter and 500 mm in length) while resolving each particle individually. Such simulations make possible to study the damage of the target from synergistic effects of individual impacts. In our research we fixed the velocity distribution along the axis of the stream (1-4 km/s) and volume fraction of the solid material (1-10%) and study effects of particle size variation, particle and target material properties and surrounding air properties. We ran 3D calibration simulations with up to 10 million individual particles and conducted sensitivity studies with 2D cylindrically symmetric simulations. We used an Eulerian Godunov hydrocode with adaptive mesh refinement. The particles, target material and air are represented with volume-of-fluid approach. Brittle particle and target material has been simulated with pressure-dependent yield strength and Steinberg model has been used for metal targets. Simulations demonstrated penetration depth and a hole diameter similar to experimental observations and can explain the influence of parameters of the stream on the character of the penetration.
Modeling-Computer Simulations | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al.,|(Pritchett,
Draxl, C.; Churchfield, M.; Mirocha, J.; Lee, S.; Lundquist, J.; Michalakes, J.; Moriarty, P.; Purkayastha, A.; Sprague, M.; Vanderwende, B.
2014-06-01T23:59:59.000Z
Wind plant aerodynamics are influenced by a combination of microscale and mesoscale phenomena. Incorporating mesoscale atmospheric forcing (e.g., diurnal cycles and frontal passages) into wind plant simulations can lead to a more accurate representation of microscale flows, aerodynamics, and wind turbine/plant performance. Our goal is to couple a numerical weather prediction model that can represent mesoscale flow [specifically the Weather Research and Forecasting model] with a microscale LES model (OpenFOAM) that can predict microscale turbulence and wake losses.
W. Schmidt; J. C. Niemeyer; W. Hillebrandt
2006-01-23T23:59:59.000Z
We present a one-equation subgrid scale model that evolves the turbulence energy corresponding to unresolved velocity fluctuations in large eddy simulations. The model is derived in the context of the Germano consistent decomposition of the hydrodynamical equations. The eddy-viscosity closure for the rate of energy transfer from resolved toward subgrid scales is localised by means of a dynamical procedure for the computation of the closure parameter. Therefore, the subgrid scale model applies to arbitrary flow geometry and evolution. For the treatment of microscopic viscous dissipation a semi-statistical approach is used, and the gradient-diffusion hypothesis is adopted for turbulent transport. A priori tests of the localised eddy-viscosity closure and the gradient-diffusion closure are made by analysing data from direct numerical simulations. As an a posteriori testing case, the large eddy simulation of thermonuclear combustion in forced isotropic turbulence is discussed. We intend the formulation of the subgrid scale model in this paper as a basis for more advanced applications in numerical simulations of complex astrophysical phenomena involving turbulence.
Middleton, Stuart E.
advanced biomedical simulation applications. Often, however, such applications have a very limited methodology advances. The European GEMSS Project [7] is concerned with the creation of medical Grid service1 Numerical Simulation for eHealth: Gridenabled Medical Simulation Services Siegfried Benkner
Schmidt, W; Niemeyer, J C
2006-01-01T23:59:59.000Z
We present a one-equation subgrid scale model that evolves the turbulence energy corresponding to unresolved velocity fluctuations in large eddy simulations. The model is derived in the context of the Germano consistent decomposition of the hydrodynamical equations. The eddy-viscosity closure for the rate of energy transfer from resolved toward subgrid scales is localised by means of a dynamical procedure for the computation of the closure parameter. Therefore, the subgrid scale model applies to arbitrary flow geometry and evolution. For the treatment of microscopic viscous dissipation a semi-statistical approach is used, and the gradient-diffusion hypothesis is adopted for turbulent transport. A priori tests of the localised eddy-viscosity closure and the gradient-diffusion closure are made by analysing data from direct numerical simulations. As an a posteriori testing case, the large eddy simulation of thermonuclear combustion in forced isotropic turbulence is discussed. We intend the formulation of the sub...
Figueroa, Aldo [Facultad de Ciencias, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos 62209 (Mexico)] [Facultad de Ciencias, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos 62209 (Mexico); Meunier, Patrice; Villermaux, Emmanuel [Aix-Marseille Univ., CNRS, Centrale Marseille, IRPHE, Marseille F-13384 (France)] [Aix-Marseille Univ., CNRS, Centrale Marseille, IRPHE, Marseille F-13384 (France); Cuevas, Sergio; Ramos, Eduardo [Instituto de Energías Renovables, Universidad Nacional Autónoma de México, A.P. 34, Temixco, Morelos 62580 (Mexico)] [Instituto de Energías Renovables, Universidad Nacional Autónoma de México, A.P. 34, Temixco, Morelos 62580 (Mexico)
2014-01-15T23:59:59.000Z
We present a combination of experiment, theory, and modelling on laminar mixing at large Péclet number. The flow is produced by oscillating electromagnetic forces in a thin electrolytic fluid layer, leading to oscillating dipoles, quadrupoles, octopoles, and disordered flows. The numerical simulations are based on the Diffusive Strip Method (DSM) which was recently introduced (P. Meunier and E. Villermaux, “The diffusive strip method for scalar mixing in two-dimensions,” J. Fluid Mech. 662, 134–172 (2010)) to solve the advection-diffusion problem by combining Lagrangian techniques and theoretical modelling of the diffusion. Numerical simulations obtained with the DSM are in reasonable agreement with quantitative dye visualization experiments of the scalar fields. A theoretical model based on log-normal Probability Density Functions (PDFs) of stretching factors, characteristic of homogeneous turbulence in the Batchelor regime, allows to predict the PDFs of scalar in agreement with numerical and experimental results. This model also indicates that the PDFs of scalar are asymptotically close to log-normal at late stages, except for the large concentration levels which correspond to low stretching factors.
Numerical simulations of impulsively generated Alfvén waves in solar magnetic arcades
Chmielewski, P.; Murawski, K. [Group of Astrophysics, UMCS, ul. Radziszewskiego 10, 20-031 Lublin (Poland); Musielak, Z. E. [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States); Srivastava, A. K. [Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)
2014-09-20T23:59:59.000Z
We perform numerical simulations of impulsively generated Alfvén waves in an isolated solar arcade, which is gravitationally stratified and magnetically confined. We study numerically the propagation of Alfvén waves along the magnetic structure that extends from the lower chromosphere, where the waves are generated, to the solar corona, and analyze the influence of the arcade size and the width of the initial pulses on the wave propagation and reflection. Our model of the solar atmosphere is constructed by adopting the temperature distribution based on the semi-empirical VAL-C model and specifying the curved magnetic field lines that constitute the asymmetric magnetic arcade. The propagation and reflection of Alfvén waves in this arcade is described by 2.5-dimensional magnetohydrodynamic equations that are numerically solved by the FLASH code. Our numerical simulations reveal that the Alfvén wave amplitude decreases as a result of a partial reflection of Alfvén waves in the solar transition region, and that the waves that are not reflected leak through the transition region and reach the solar corona. We also find the decrement of the attenuation time of Alfvén waves for wider initial pulses. Moreover, our results show that the propagation of Alfvén waves in the arcade is affected by the spatial dependence of the Alfvén speed, which leads to phase mixing that is stronger for more curved and larger magnetic arcades. We discuss the processes that affect the Alfvén wave propagation in an asymmetric solar arcade and conclude that besides phase mixing in the magnetic field configuration, the plasma properties of the arcade, the size of the initial pulse, and the structure of the solar transition region all play a vital role in the Alfvén wave propagation.
Statistically Steady Turbulence in Soap Films: Direct Numerical Simulations with Ekman Friction
Prasad Perlekar; Rahul Pandit
2008-11-09T23:59:59.000Z
We present a detailed direct numerical simulation (DNS) designed to investigate the combined effects of walls and Ekman friction on turbulence in forced soap films. We concentrate on the forward-cascade regime and show how to extract the isotropic parts of velocity and vorticity structure functions and thence the ratios of multiscaling exponents. We find that velocity structure functions display simple scaling whereas their vorticity counterparts show multiscaling; and the probability distribution function of the Weiss parameter $\\Lambda$, which distinguishes between regions with centers and saddles, is in quantitative agreement with experiments.
Laprea-Bigott, Marcelo
1976-01-01T23:59:59.000Z
SIMULATION OF FLUID DISPLACEMENT IN POROUS MEDIA ? IMPROVED METHODS TO MINIMIZE NUMERICAL DISPERSION AND GRID ORIENTATION EFFECTS A Thesis by MARCELO LAPREA-BIGOTT Submitted to the Graduate College of Texas A8M University in partial... fulfillment of the requirement for the degree of MASTER OF SCIENCE December 1976 Major Subject: Petroleum Engineering SIMULATION OF FLUID DISPLACEMENT IN POROUS MEDIA - IMPROVED METHODS TO MINIMIZE NUMERICAL DISPERSION AND GRID ORIENTATION EFFECTS A...
Phung, Anh Ngoc
1995-01-01T23:59:59.000Z
The complicated fluid flow at the tip of a typical bristle within a brush seal is simulated. A numerical model is developed to compute the three-dimensional details in the bristle tip region. Experimental and numerical leakage data are correlated...
Phung, Anh Ngoc
1995-01-01T23:59:59.000Z
The complicated fluid flow at the tip of a typical bristle within a brush seal is simulated. A numerical model is developed to compute the three-dimensional details in the bristle tip region. Experimental and numerical leakage data are correlated...
The Origin and Kinematics of Cold Gas in Galactic Winds: Insight from Numerical Simulations
Fujita, Akimi; Mac Low, Mordecai-Mark; New, Kimberly C B; Weaver, Robert
2008-01-01T23:59:59.000Z
We study the origin of Na I absorbing gas in ultraluminous infrared galaxies motivated by the recent observations by Martin of extremely superthermal linewidths in this cool gas. We model the effects of repeated supernova explosions driving supershells in the central regions of molecular disks with M_d=10^{10} M_{\\odot}, using cylindrically symmetric gas dynamical simulations run with ZEUS-3D. The shocked swept-up shells quickly cool and fragment by Rayleigh-Taylor instability as they accelerate out of the dense, stratified disks. The numerical resolution of the cooling and compression at the shock fronts determines the peak shell density, and so the speed of Rayleigh-Taylor fragmentation. We identify cooled shells and shell fragments as Na I absorbing gas and study its kinematics along various sightlines across the grid. We find that simulations with a numerical resolution of \\le 0.2 pc produce multiple Rayleigh-Taylor fragmented shells in a given line of sight that appear to explain the observed kinematics....
Numerical simulation of turbulent heat transfer in an annular fuel channel augmented by spacer ribs
Takase, Kazuyuki; Akino, Norio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Dept. of High Temperature Engineering
1995-12-31T23:59:59.000Z
Thermal-hydraulic characteristics of fuel channels with three dimensional trapezoidal spacer ribs for high temperature gas-cooled reactors were investigated under the same coolant conditions as the reactor operation, maximum fuel channel outlet temperature of 1,000 C and pressure of 4 MPa, and analytically by numerical simulations using the {kappa}-{var_epsilon} turbulence model. The turbulent heat transfer coefficients in the spacer ribbed fuel channel were 20 to 100% higher than those in a concentric smooth annulus for a region of Reynolds number exceeding 2,000. Furthermore, the predicted Nusselt number in the spacer ribbed fuel channel was in good agreement with the empirical correlation obtained from the present experimental data within an error of 10% with Reynolds number of more than 5000. On the other hand, the friction factors in the spacer ribbed fuel channel were higher than those in the smooth duct in the turbulent region, and also they could be predicted with sufficient accuracy. In addition, the present numerical simulation could clarify quantitatively the effects of the heat transfer augmentation due to the spacer ribs and the axial velocity increase due to a reduction in the annular channel cross-section.
A phase screen model for simulating numerically the propagation of a laser beam in rain
Lukin, I P; Rychkov, D S; Falits, A V [Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, Tomsk (Russian Federation); Lai, Kin S; Liu, Min R [DSO National Laboratories 20 (Singapore)
2009-09-30T23:59:59.000Z
The method based on the generalisation of the phase screen method for a continuous random medium is proposed for simulating numerically the propagation of laser radiation in a turbulent atmosphere with precipitation. In the phase screen model for a discrete component of a heterogeneous 'air-rain droplet' medium, the amplitude screen describing the scattering of an optical field by discrete particles of the medium is replaced by an equivalent phase screen with a spectrum of the correlation function of the effective dielectric constant fluctuations that is similar to the spectrum of a discrete scattering component - water droplets in air. The 'turbulent' phase screen is constructed on the basis of the Kolmogorov model, while the 'rain' screen model utiises the exponential distribution of the number of rain drops with respect to their radii as a function of the rain intensity. Theresults of the numerical simulation are compared with the known theoretical estimates for a large-scale discrete scattering medium. (propagation of laser radiation in matter)
Time and length scales within a fire and implications for numerical simulation
TIESZEN,SHELDON R.
2000-02-02T23:59:59.000Z
A partial non-dimensionalization of the Navier-Stokes equations is used to obtain order of magnitude estimates of the rate-controlling transport processes in the reacting portion of a fire plume as a function of length scale. Over continuum length scales, buoyant times scales vary as the square root of the length scale; advection time scales vary as the length scale, and diffusion time scales vary as the square of the length scale. Due to the variation with length scale, each process is dominant over a given range. The relationship of buoyancy and baroclinc vorticity generation is highlighted. For numerical simulation, first principles solution for fire problems is not possible with foreseeable computational hardware in the near future. Filtered transport equations with subgrid modeling will be required as two to three decades of length scale are captured by solution of discretized conservation equations. By whatever filtering process one employs, one must have humble expectations for the accuracy obtainable by numerical simulation for practical fire problems that contain important multi-physics/multi-length-scale coupling with up to 10 orders of magnitude in length scale.
A review on recent advances in the numerical simulation for coalbed-methane-recovery process
Wei, X.R.; Wang, G.X.; Massarotto, P.; Golding, S.D.; Rudolph, V. [University of Queensland, Brisbane, Qld. (Australia)
2007-12-15T23:59:59.000Z
The recent advances in numerical simulation for primary coalbed methane (CBM) recovery and enhanced coalbed-methane recovery (ECBMR) processes are reviewed, primarily focusing on the progress that has occurred since the late 1980s. Two major issues regarding the numerical modeling will be discussed in this review: first, multicomponent gas transport in in-situ bulk coal and, second, changes of coal properties during methane (CH{sub 4}) production. For the former issues, a detailed review of more recent advances in modeling gas and water transport within a coal matrix is presented. Further, various factors influencing gas diffusion through the coal matrix will be highlighted as well, such as pore structure, concentration and pressure, and water effects. An ongoing bottleneck for evaluating total mass transport rate is developing a reasonable representation of multiscale pore space that considers coal type and rank. Moreover, few efforts have been concerned with modeling water-flow behavior in the coal matrix and its effects on CH{sub 4} production and on the exchange of carbon dioxide (CO{sub 2}) and CH{sub 4}. As for the second issue, theoretical coupled fluid-flow and geomechanical models have been proposed to describe the evolution of pore structure during CH{sub 4} production, instead of traditional empirical equations. However, there is currently no effective coupled model for engineering applications. Finally, perspectives on developing suitable simulation models for CBM production and for predicting CO{sub 2}-sequestration ECBMR are suggested.
Torres-Verdín, Carlos
SPE 159250 Forecasting Gas Production in Organic Shale with the Combined Numerical Simulation algorithm to forecast gas production in organic shale that simultaneously takes into account gas diffusion-than-expected permeability in shale-gas formations, while Langmuir desorption maintains pore pressure. Simulations confirm
A numerical model of aerosol scavenging. Part 2, Simulation of a large city fire
Bradley, M.M.; Molenkamp, C.R.
1991-10-01T23:59:59.000Z
Using a three-dimensional numerical cloud/smoke-plume model, we have simulated the burning of a large, mid-latitude city following a nuclear exchange. The model includes 18 dynamic and microphysical equations that predict the fire-driven airflow, cloud processes, and smoke-cloud interactions. In the simulation, the intense heating from the burning city produces a firestorm with updraft velocities exceeding 60 m/s. Within 15 minutes of ignition, the smoke plume penetrates the tropopause. The updraft triggers a cumulonimbus cloud that produces significant quantities of ice, snow, and hail. These solid hydrometeors, as well as cloud droplets and rain, interact with the smoke particles from the fire. At the end of the one-hour simulation, over 20% of the smoke is in slowly falling snowflakes. If the snow reaches the ground before the flakes completely sublimate (or melt and then evaporate), then only approximately 50% of the smoke will survive the scavenging processes and remain in the atmosphere to affect the global climate.
Two-scale numerical simulation of the weakly compressible 1D isentropic Euler equations
Frénod, Emmanuel
to simulate plasmas submitted to strong magnetic field. Of course, simulations of magnetic confinement fusion
A direct numerical simulation method for complex modulus of particle dispersions
T. Iwashita; T. Kumagai; R. Yamamoto
2010-04-24T23:59:59.000Z
We report an extension of the smoothed profile method (SPM)[Y. Nakayama, K. Kim, and R. Yamamoto, Eur. Phys. J. E {\\bf 26}, 361(2008)], a direct numerical simulation method for calculating the complex modulus of the dispersion of particles, in which we introduce a temporally oscillatory external force into the system. The validity of the method was examined by evaluating the storage $G'(\\omega)$ and loss $G"(\\omega)$ moduli of a system composed of identical spherical particles dispersed in an incompressible Newtonian host fluid at volume fractions of $\\Phi=0$, 0.41, and 0.51. The moduli were evaluated at several frequencies of shear flow; the shear flow used here has a zigzag profile, as is consistent with the usual periodic boundary conditions.
Skinner, M Aaron
2015-01-01T23:59:59.000Z
Radiation feedback from young star clusters embedded in giant molecular clouds (GMCs) is believed to be important to the control of star formation. For the most massive and dense clouds, including those in which super star clusters (SSCs) are born, pressure from reprocessed radiation exerted on dust grains may disperse a significant portion of the cloud mass back into the interstellar medium (ISM). Using our radiaton hydrodynamics (RHD) code, Hyperion, we conduct a series of numerical simulations to test this idea. Our models follow the evolution of self-gravitating, strongly turbulent clouds in which collapsing regions are replaced by radiating sink particles representing stellar clusters. We evaluate the dependence of the star formation efficiency (SFE) on the size and mass of the cloud and $\\kappa$, the opacity of the gas to infrared (IR) radiation. We find that the single most important parameter determining the evolutionary outcome is $\\kappa$, with $\\kappa \\gtrsim 15 \\text{ cm}^2 \\text{ g}^{-1}$ needed ...
The Origin and Kinematics of Cold Gas in Galactic Winds: Insight from Numerical Simulations
Akimi Fujita; Crystal L. Martin; Mordecai-Mark Mac Low; Kimberly C. B. New; Robert Weaver
2009-04-02T23:59:59.000Z
We study the origin of Na I absorbing gas in ultraluminous infrared galaxies motivated by the recent observations by Martin of extremely superthermal linewidths in this cool gas. We model the effects of repeated supernova explosions driving supershells in the central regions of molecular disks with M_d=10^10 M_\\sun, using cylindrically symmetric gas dynamical simulations run with ZEUS-3D. The shocked swept-up shells quickly cool and fragment by Rayleigh-Taylor instability as they accelerate out of the dense, stratified disks. The numerical resolution of the cooling and compression at the shock fronts determines the peak shell density, and so the speed of Rayleigh-Taylor fragmentation. We identify cooled shells and shell fragments as Na I absorbing gas and study its kinematics. We find that simulations with a numerical resolution of \\le 0.2 pc produce multiple Rayleigh-Taylor fragmented shells in a given line of sight. We suggest that the observed wide Na I absorption lines, = 320 \\pm 120 km s^-1 are produced by these multiple fragmented shells traveling at different velocities. We also suggest that some shell fragments can be accelerated above the observed average terminal velocity of 750 km s^-1 by the same energy-driven wind with an instantaneous starburst of \\sim 10^9 M_\\sun. The bulk of mass is traveling with the observed average shell velocity 330 \\pm 100 km s^-1. Our results show that an energy-driven bubble causing Rayleigh-Taylor instabilities can explain the kinematics of cool gas seen in the Na I observations without invoking additional physics relying primarily on momentum conservation, such as entrainment of gas by Kelvin-Helmholtz instabilities, ram pressure driving of cold clouds by a hot wind, or radiation pressure acting on dust. (abridged)
GPU accelerated flow solver for direct numerical simulation of turbulent flows
Salvadore, Francesco [CASPUR – via dei Tizii 6/b, 00185 Rome (Italy)] [CASPUR – via dei Tizii 6/b, 00185 Rome (Italy); Bernardini, Matteo, E-mail: matteo.bernardini@uniroma1.it [Department of Mechanical and Aerospace Engineering, University of Rome ‘La Sapienza’ – via Eudossiana 18, 00184 Rome (Italy)] [Department of Mechanical and Aerospace Engineering, University of Rome ‘La Sapienza’ – via Eudossiana 18, 00184 Rome (Italy); Botti, Michela [CASPUR – via dei Tizii 6/b, 00185 Rome (Italy)] [CASPUR – via dei Tizii 6/b, 00185 Rome (Italy)
2013-02-15T23:59:59.000Z
Graphical processing units (GPUs), characterized by significant computing performance, are nowadays very appealing for the solution of computationally demanding tasks in a wide variety of scientific applications. However, to run on GPUs, existing codes need to be ported and optimized, a procedure which is not yet standardized and may require non trivial efforts, even to high-performance computing specialists. In the present paper we accurately describe the porting to CUDA (Compute Unified Device Architecture) of a finite-difference compressible Navier–Stokes solver, suitable for direct numerical simulation (DNS) of turbulent flows. Porting and validation processes are illustrated in detail, with emphasis on computational strategies and techniques that can be applied to overcome typical bottlenecks arising from the porting of common computational fluid dynamics solvers. We demonstrate that a careful optimization work is crucial to get the highest performance from GPU accelerators. The results show that the overall speedup of one NVIDIA Tesla S2070 GPU is approximately 22 compared with one AMD Opteron 2352 Barcelona chip and 11 compared with one Intel Xeon X5650 Westmere core. The potential of GPU devices in the simulation of unsteady three-dimensional turbulent flows is proved by performing a DNS of a spatially evolving compressible mixing layer.
Hindmarsh, Mark; Rummukainen, Kari; Weir, David J
2015-01-01T23:59:59.000Z
We present details of numerical simulations of the gravitational radiation produced by a first order {thermal} phase transition in the early universe. We confirm that the dominant source of gravitational waves is sound waves generated by the expanding bubbles of the low-temperature phase. We demonstrate that the sound waves have a power spectrum with power-law form between the scales set by the average bubble separation (which sets the length scale of the fluid flow $L_\\text{f}$) and the bubble wall width. The sound waves generate gravitational waves whose power spectrum also has a power-law form, at a rate proportional to $L_\\text{f}$ and the square of the fluid kinetic energy density. We identify a dimensionless parameter $\\tilde\\Omega_\\text{GW}$ characterising the efficiency of this "acoustic" gravitational wave production whose value is $8\\pi\\tilde\\Omega_\\text{GW} \\simeq 0.8 \\pm 0.1$ across all our simulations. We compare the acoustic gravitational waves with the standard prediction from the envelope appr...
Mark Hindmarsh; Stephan J. Huber; Kari Rummukainen; David J. Weir
2015-04-13T23:59:59.000Z
We present details of numerical simulations of the gravitational radiation produced by a first order {thermal} phase transition in the early universe. We confirm that the dominant source of gravitational waves is sound waves generated by the expanding bubbles of the low-temperature phase. We demonstrate that the sound waves have a power spectrum with power-law form between the scales set by the average bubble separation (which sets the length scale of the fluid flow $L_\\text{f}$) and the bubble wall width. The sound waves generate gravitational waves whose power spectrum also has a power-law form, at a rate proportional to $L_\\text{f}$ and the square of the fluid kinetic energy density. We identify a dimensionless parameter $\\tilde\\Omega_\\text{GW}$ characterising the efficiency of this "acoustic" gravitational wave production whose value is $8\\pi\\tilde\\Omega_\\text{GW} \\simeq 0.8 \\pm 0.1$ across all our simulations. We compare the acoustic gravitational waves with the standard prediction from the envelope approximation. Not only is the power spectrum steeper (apart from an initial transient) but the gravitational wave energy density is generically two orders of magnitude or more larger.
Numerical simulation of laminar plasma dynamos in a cylindrical von Karman flow
Khalzov, I. V.; Brown, B. P.; Schnack, D. D.; Forest, C. B. [University of Wisconsin, 1150 University Avenue, Madison, Wisconsin 53706 (United States); Ebrahimi, F. [University of New Hampshire, 8 College Road, Durham, New Hampshire 03824 (United States)
2011-03-15T23:59:59.000Z
The results of a numerical study of the magnetic dynamo effect in cylindrical von Karman plasma flow are presented with parameters relevant to the Madison Plasma Couette Experiment. This experiment is designed to investigate a broad class of phenomena in flowing plasmas. In a plasma, the magnetic Prandtl number Pm can be of order unity (i.e., the fluid Reynolds number Re is comparable to the magnetic Reynolds number Rm). This is in contrast to liquid metal experiments, where Pm is small (so, Re>>Rm) and the flows are always turbulent. We explore dynamo action through simulations using the extended magnetohydrodynamic NIMROD code for an isothermal and compressible plasma model. We also study two-fluid effects in simulations by including the Hall term in Ohm's law. We find that the counter-rotating von Karman flow results in sustained dynamo action and the self-generation of magnetic field when the magnetic Reynolds number exceeds a critical value. For the plasma parameters of the experiment, this field saturates at an amplitude corresponding to a new stable equilibrium (a laminar dynamo). We show that compressibility in the plasma results in an increase of the critical magnetic Reynolds number, while inclusion of the Hall term in Ohm's law changes the amplitude of the saturated dynamo field but not the critical value for the onset of dynamo action.
Numerical simulation of laminar plasma dynamos in a cylindrical von K\\'arm\\'an flow
Khalzov, I V; Ebrahimi, F; Schnack, D D; Forest, C B; 10.1063/1.3559472
2011-01-01T23:59:59.000Z
The results of a numerical study of the magnetic dynamo effect in cylindrical von K\\'arm\\'an plasma flow are presented with parameters relevant to the Madison Plasma Couette Experiment. This experiment is designed to investigate a broad class of phenomena in flowing plasmas. In a plasma, the magnetic Prandtl number Pm can be of order unity (i.e., the fluid Reynolds number Re is comparable to the magnetic Reynolds number Rm). This is in contrast to liquid metal experiments, where Pm is small (so, Re>>Rm) and the flows are always turbulent. We explore dynamo action through simulations using the extended magnetohydrodynamic NIMROD code for an isothermal and compressible plasma model.We also study two-fluid effects in simulations by including the Hall term in Ohm's law. We find that the counter-rotating von K\\'arm\\'an flow results in sustained dynamo action and the self-generation of magnetic field when the magnetic Reynolds number exceeds a critical value. For the plasma parameters of the experiment, this field ...
Numerical simulations of two-phase Taylor-Couette turbulence using an Euler-Lagrange approach
Spandan, Vamsi; Verzicco, Roberto; Lohse, Detlef
2015-01-01T23:59:59.000Z
Two-phase turbulent Taylor-Couette (TC) flow is simulated using an Euler-Lagrange approach to study the effects of a secondary phase dispersed into a turbulent carrier phase (here bubbles dispersed into water). The dynamics of the carrier phase is computed using Direct Numerical Simulations (DNS) in an Eulerian framework, while the bubbles are tracked in a Lagrangian manner by modelling the effective drag, lift, added mass and buoyancy force acting on them. Two-way coupling is implemented between the dispersed phase and the carrier phase which allows for momentum exchange among both phases and to study the effect of the dispersed phase on the carrier phase dynamics. The radius ratio of the TC setup is fixed to $\\eta=0.833$, and a maximum inner cylinder Reynolds number of $Re_i=8000$ is reached. We vary the Froude number ($Fr$), which is the ratio of the centripetal to the gravitational acceleration of the dispersed phase and study its effect on the net torque required to drive the TC system. In a two-phase TC...
Numerical relativity simulations of thick accretion disks around tilted Kerr black holes
Vassilios Mewes; José A. Font; Filippo Galeazzi; Pedro J. Montero; Nikolaos Stergioulas
2015-06-12T23:59:59.000Z
In this work we present 3D numerical relativity simulations of thick accretion disks around {\\it tilted} Kerr black holes. We investigate the evolution of three different initial disk models with a range of initial black hole spin magnitudes and tilt angles. For all the disk-to-black hole mass ratios considered ($0.044-0.16$) we observe significant black hole precession and nutation during the evolution. This indicates that for such mass ratios, neglecting the self-gravity of the disks by evolving them in a fixed background black hole spacetime is not justified. We find that the two more massive models are unstable against the Papaloizou-Pringle (PP) instability and that those PP-unstable models remain unstable for all initial spins and tilt angles considered, showing that the development of the instability is a very robust feature of such PP-unstable disks. The tilt between the black hole spin and the disk is strongly modulated during the growth of the PP instability, causing a partial global realignment of black hole spin and disk angular momentum in the most massive model with constant specific angular momentum $l$. For the model with non-constant $l$-profile we observe a long-lived $m=1$ non-axisymmetric structure which shows strong oscillations of the tilt angle in the inner regions of the disk. We attribute this effect to the development of Kozai-Lidov oscillations. Our simulations also confirm earlier findings that the development of the PP instability causes the long-term emission of large amplitude gravitational waves, predominantly for the $l=m=2$ multipole mode. The imprint of the BH precession on the gravitational waves from tilted BH-torus systems remains an interesting open issue that would require significantly longer simulations than those presented in this work.
TOUGH2: A general-purpose numerical simulator for multiphase nonisothermal flows
Pruess, K. [Lawrence Berkeley Lab., CA (United States)
1991-06-01T23:59:59.000Z
Numerical simulators for multiphase fluid and heat flows in permeable media have been under development at Lawrence Berkeley Laboratory for more than 10 yr. Real geofluids contain noncondensible gases and dissolved solids in addition to water, and the desire to model such `compositional` systems led to the development of a flexible multicomponent, multiphase simulation architecture known as MULKOM. The design of MULKOM was based on the recognition that the mass-and energy-balance equations for multiphase fluid and heat flows in multicomponent systems have the same mathematical form, regardless of the number and nature of fluid components and phases present. Application of MULKOM to different fluid mixtures, such as water and air, or water, oil, and gas, is possible by means of appropriate `equation-of-state` (EOS) modules, which provide all thermophysical and transport parameters of the fluid mixture and the permeable medium as a function of a suitable set of primary thermodynamic variables. Investigations of thermal and hydrologic effects from emplacement of heat-generating nuclear wastes into partially water-saturated formations prompted the development and release of a specialized version of MULKOM for nonisothermal flow of water and air, named TOUGH. TOUGH is an acronym for `transport of unsaturated groundwater and heat` and is also an allusion to the tuff formations at Yucca Mountain, Nevada. The TOUGH2 code is intended to supersede TOUGH. It offers all the capabilities of TOUGH and includes a considerably more general subset of MULKOM modules with added capabilities. The paper briefly describes the simulation methodology and user features.
Jha, Pallavi; Kumar Verma, Nirmal [Department of Physics, University of Lucknow, Lucknow-226007 (India)
2014-06-15T23:59:59.000Z
A one-dimensional numerical model for studying terahertz radiation generation by intense laser pulses propagating, in the extraordinary mode, through magnetized plasma has been presented. The direction of the static external magnetic field is perpendicular to the polarization as well as propagation direction of the laser pulse. A transverse electromagnetic wave with frequency in the terahertz range is generated due to the presence of the magnetic field. Further, two-dimensional simulations using XOOPIC code show that the THz fields generated in plasma are transmitted into vacuum. The fields obtained via simulation study are found to be compatible with those obtained from the numerical model.
Kirby, James T.
Numerical Simulation of the 2011 Tohoku Tsunami Based on a New Transient FEM Co-seismic Source Abstract--In this work, we simulate the 2011 M9 Tohoku-Oki tsunami using new coseismic tsunami sources com- pare observations and numerical simulations of the tsunami's far- and near-field coastal impact
Olshanskii, Maxim A.
and accurate numerical methods for computing flows with free surfaces and interfaces, see, e.g., [1, 2 is studied in a series of numerical experiments. Institute of Numerical Mathematics, Russian Academy@math.uh.edu Department of Energy Resources Engineering, Stanford University and Institute of Numerical Mathematics
Mohaghegh, Shahab
with a large number of producers, second, to a CO2 sequestration project in Australia, and finally to a numerical simulation study of potential carbon storage site in the United States. The numerical reservoir
Homicz, G.F.
1991-09-01T23:59:59.000Z
Blade fatigue life is an important element in determining the economic viability of the Vertical-Axis Wind Turbine (VAWT). A principal source of blade fatigue is thought to be the stochastic (i.e., random) aerodynamic loads created by atmospheric turbulence. This report describes the theoretical background of the VAWT Stochastic Aerodynamic Loads (VAWT-SAL) computer code, whose purpose is to numerically simulate these random loads, given the rotor geometry, operating conditions, and assumed turbulence properties. A Double-Multiple-Stream Tube (DMST) analysis is employed to model the rotor's aerodynamic response. The analysis includes the effects of Reynolds number variations, different airfoil sections and chord lengths along the blade span, and an empirical model for dynamic stall effects. The mean ambient wind is assumed to have a shear profile which is described by either a power law or a logarithmic variation with height above ground. Superimposed on this is a full 3-D field of turbulence: i.e., in addition to random fluctuations in time, the turbulence is allowed to vary randomly in planes perpendicular to the mean wind. The influence of flow retardation on the convection of turbulence through the turbine is also modeled. Calculations are presented for the VAWT 34-m Test Bed currently in operation at Bushland, Texas. Predicted time histories of the loads, as well as their Fourier spectra, are presented and discussed. Particular emphasis is placed on the differences between so-called steady-state'' (mean wind only) predictions, and those produced with turbulence present. Somewhat surprisingly, turbulence is found to be capable of either increasing or decreasing the average output power, depending on the turbine's tip-speed ratio. A heuristic explanation for such behavior is postulated, and a simple formula is derived for predicting the magnitude of this effect without the need for a full stochastic simulation. 41 refs., 32 figs., 1 tab.
Numerical relativity simulations of neutron star merger remnants using conservative mesh refinement
Tim Dietrich; Sebastiano Bernuzzi; Maximiliano Ujevic; Bernd Bruegmann
2015-04-06T23:59:59.000Z
We study equal and unequal-mass neutron star mergers by means of new numerical relativity simulations in which the general relativistic hydrodynamics solver employs an algorithm that guarantees mass conservation across the refinement levels of the computational mesh. We consider eight binary configurations with total mass $M=2.7\\,M_\\odot$, mass-ratios $q=1$ and $q=1.16$, and four different equation of states (EOSs), and one configuration with a stiff EOS, $M=2.5M_\\odot$ and $q=1.5$. We focus on the post-merger dynamics and study the merger remnant, dynamical ejecta and the postmerger gravitational wave spectrum. Although most of the merger remnants form a hypermassive neutron star collapsing to a black hole+disk system on dynamical timescales, stiff EOSs can eventually produce a stable massive neutron star. Ejecta are mostly emitted around the orbital plane; favored by large mass ratios and softer EOS. The postmerger wave spectrum is mainly characterized by non-axisymmetric oscillations of the remnant. The stiff EOS configuration consisting of a $1.5M_\\odot$ and a $1.0M_\\odot$ neutron star shows a rather peculiar dynamics. During merger the companion star is very deformed; about~$\\sim0.03M_\\odot$ of rest-mass becomes unbound from the tidal tail due torque; and the merger remnant forms stable neutron star surrounded by a massive accretion disk $\\sim0.3M_\\odot$. Similar configurations might be particularly interesting for electromagnetic counterparts. Comparing results obtained with and without the conservative mesh refinement algorithm, we find that post-merger simulations can be affected by systematic errors if mass conservation is not enforced in the mesh refinement strategy. However, mass conservation also depends on grid details and on the artificial atmosphere setup. [abridged
Aktinol, Eduardo
2014-01-01T23:59:59.000Z
Numerical Simulation of Pool Boiling: A Review. ” Journal ofBooth, W. (2012). “Nucleate Pool Boiling Experiments (NPBX)and Booth, W. , “ ,Nucleate Pool Boiling Experiments (NPBX)
Boyer, Edmond
Introduction Flattening the Earth Continuation procedure Flat Earth Numerical simulations Continuation from a flat to a round Earth model in the coplanar orbit transfer problem M. Cerf1, T. Haberkorn, SADCO 2011, March 2nd M. Cerf, T. Haberkorn, E. Tr´elat Continuation from a flat to a round Earth model
Bell, John B.
Multidimensional Numerical Simulation of a Pulse Combustor \\Lambda Daniel L. Marcus, Richard B Abstract We have developed a new threedimensional modeling capability to study the behavior of pulsedimensional, reacting fluid dynamics in the combustion chamber and in corporates lowerdimensional approximations
Torres-Verdín, Carlos
and reliable use in non-vertical wells. This paper undertakes the numerical simulation of dual of highly deviated wells to reduce drilling costs and improve production efficiency. This situation has Modern hydrocarbon development techniques make extensive use of highly deviated and horizontal wells
Rider, William; Kamm, J. R. (James R.); Tomkins, C. D. (Chris D.); Prestridge, K. P. (Katherine P.); Rightley, P. M. (Paul M.); Benjamin, R. F. (Robert F.); Zoldi, C. A. (Cindy A.)
2001-01-01T23:59:59.000Z
Validation of numerical simulations, Le., the quantitative comparison of calculated results with experimental data, is an essential practice in computational fluid dynamics. These comparisons are particularly difficult in the field of shock-accelerated fluid mixing, which can be dominated by irregular structures induced by flow instabilities. Such flows exhibit non-deterministic behavior, which eliminates my direct way to establish correspondence between experimental data and numerical simulation. We examine the detailed structures of mixing experiments and their simulation for Richtmyer-Meshkov (RM) experiments of Prestridge et al., Tomkins et al., and Jacobs. Numerical simulations of these experiments will be performed with several different high-resolution shock capturing schemes, including a variety of finite volume Godunov methods. We compare the experimental data for cOnfigurations of one and two diffuse cylinders of SF6 in air with numerical results using several multiscale metrics: fractal analysis, continuous wavelet transforms, and generalized correlations; these measures complement traditional metrics such as PDFs, mix fractions, and integral mixing widths.
Kirby, James T.
for the purpose of a tsunami warning system. In this context we describe the Thailand case study of the 26th, warning system, Thailand case study Introduction Any fast deformation of the ocean sea floor may, in some2 Keynote 2 How Numerical Simulations May Contribute to Tsunami Risk Preparedness: The 26 December
Komatitsch, Dimitri
derivatives or analytical expressions to compute the rotational Green's tensor. We validate the method using Numerical Simulation of Ground Rotations along 2D Topographical Profiles under the Incidence-Sesma, R. Madec, and D. Komatitsch Abstract The surface displacement field along a topographical profile
Physical mechanism and numerical simulation of the inception of the lightning upward leader
Li Qingmin [Beijing Key Lab of High Voltage and EMC, School of Electric and Electronic Engineering, North China Electric Power University, Beijing 102206 (China) and State Key Lab of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206 (China); Lu Xinchang; Shi Wei; Zhang Li; Zou Liang; Lou Jie [Shandong Provincial Key Lab of UHV Technology and Gas Discharge, School of Electrical Engineering, Shandong University, Jinan 250061 (China)
2012-12-15T23:59:59.000Z
The upward leader is a key physical process of the leader progression model of lightning shielding. The inception mechanism and criterion of the upward leader need further understanding and clarification. Based on leader discharge theory, this paper proposes the critical electric field intensity of the stable upward leader (CEFISUL) and characterizes it by the valve electric field intensity on the conductor surface, E{sub L}, which is the basis of a new inception criterion for the upward leader. Through numerical simulation under various physical conditions, we verified that E{sub L} is mainly related to the conductor radius, and data fitting yields the mathematical expression of E{sub L}. We further establish a computational model for lightning shielding performance of the transmission lines based on the proposed CEFISUL criterion, which reproduces the shielding failure rate of typical UHV transmission lines. The model-based calculation results agree well with the statistical data from on-site operations, which show the effectiveness and validity of the CEFISUL criterion.
Evaluation and Numerical Simulation of Tsunami for Coastal Nuclear Power Plants of India
Sharma, Pavan K.; Singh, R.K.; Ghosh, A.K.; Kushwaha, H.S. [Bhabha Atomic Research Centre-Trombay, Mumbai 400 085 (India)
2006-07-01T23:59:59.000Z
Recent tsunami generated on December 26, 2004 due to Sumatra earthquake of magnitude 9.3 resulted in inundation at the various coastal sites of India. The site selection and design of Indian nuclear power plants demand the evaluation of run up and the structural barriers for the coastal plants: Besides it is also desirable to evaluate the early warning system for tsunami-genic earthquakes. The tsunamis originate from submarine faults, underwater volcanic activities, sub-aerial landslides impinging on the sea and submarine landslides. In case of a submarine earthquake-induced tsunami the wave is generated in the fluid domain due to displacement of the seabed. There are three phases of tsunami: generation, propagation, and run-up. Reactor Safety Division (RSD) of Bhabha Atomic Research Centre (BARC), Trombay has initiated computational simulation for all the three phases of tsunami source generation, its propagation and finally run up evaluation for the protection of public life, property and various industrial infrastructures located on the coastal regions of India. These studies could be effectively utilized for design and implementation of early warning system for coastal region of the country apart from catering to the needs of Indian nuclear installations. This paper presents some results of tsunami waves based on different analytical/numerical approaches with shallow water wave theory. (authors)
A numerical simulation of solar energetic particle dropouts during impulsive events
Wang, Y.; Qin, G. [State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190 (China); Zhang, M. [Department of Physics and Space Science, Florida Institute of Technology, Melbourne, FL 32901 (United States); Dalla, S., E-mail: ywang@spaceweather.ac.cn, E-mail: gqin@spaceweather.ac.cn [Jeremiah Horrocks Institute, University of Central Lancashire, Preston, Lancashire PR1 2HE (United Kingdom)
2014-07-10T23:59:59.000Z
This paper investigates the conditions for producing rapid variations of solar energetic particle (SEP) intensity commonly known as 'dropouts'. In particular, we use numerical model simulations based on solving the focused transport equation in the three-dimensional Parker interplanetary magnetic field to put constraints on the properties of particle transport coefficients in both directions perpendicular and parallel to the magnetic field. Our calculations of the temporal intensity profile of 0.5 and 5 MeV protons at the Earth show that the perpendicular diffusion must be small while the parallel mean free path is long in order to reproduce the phenomenon of SEP dropouts. When the parallel mean free path is a fraction of 1 AU and the observer is located at 1 AU, the perpendicular to parallel diffusion ratio must be below 10{sup –5} if we want to see the particle flux dropping by at least several times within 3 hr. When the observer is located at a larger solar radial distance, the perpendicular to parallel diffusion ratio for reproducing the dropouts should be even lower than that in the case of 1 AU distance. A shorter parallel mean free path or a larger radial distance from the source to observer will cause the particles to arrive later, making the effects of perpendicular diffusion more prominent and SEP dropouts disappear. All of these effects require the magnetic turbulence that resonates with the particles to be low everywhere in the inner heliosphere.
NUMERICAL FLOW AND TRANSPORT SIMULATIONS SUPPORTING THE SALTSTONE FACILITY PERFORMANCE ASSESSMENT
Flach, G.
2009-02-28T23:59:59.000Z
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.
Test of some numerical limiters for the conservative PSM scheme for 4D Drift-Kinetic simulations
Jerome Guterl; Jean-Philippe Braeunig; Nicolas Crouseilles; Virginie Grandgirard; Guillaume Latu; Michel Mehrenberger; Eric Sonnendrücker
2010-12-13T23:59:59.000Z
The purpose of this work is simulation of magnetised plasmas in the ITER project framework. In this context, Vlasov-Poisson like models are used to simulate core turbulence in the tokamak in a toroidal geometry. This leads to heavy simulation because a 6D dimensional problem has to be solved, 3D in space and 3D in velocity. The model is reduced to a 5D gyrokinetic model, taking advantage of the particular motion of particles due to the presence of a strong magnetic field. However, accurate schemes, parallel algorithms need to be designed to bear these simulations. This paper describes a Hermite formulation of the conservative PSM scheme which is very generic and allows to implement different semi-Lagrangian schemes. We also test and propose numerical limiters which should improve the robustness of the simulations by diminishing spurious oscillations. We only consider here the 4D drift-kinetic model which is the backbone of the 5D gyrokinetic models and relevant to build a robust and accurate numerical method.
Test of some numerical limiters for the conservative PSM scheme for 4D Drift-Kinetic simulations
Guterl, Jerome; Crouseilles, Nicolas; Grandgirard, Virginie; Latu, Guillaume; Mehrenberger, Michel; Sonnendrücker, Eric
2010-01-01T23:59:59.000Z
The purpose of this work is simulation of magnetised plasmas in the ITER project framework. In this context, Vlasov-Poisson like models are used to simulate core turbulence in the tokamak in a toroidal geometry. This leads to heavy simulation because a 6D dimensional problem has to be solved, 3D in space and 3D in velocity. The model is reduced to a 5D gyrokinetic model, taking advantage of the particular motion of particles due to the presence of a strong magnetic field. However, accurate schemes, parallel algorithms need to be designed to bear these simulations. This paper describes a Hermite formulation of the conservative PSM scheme which is very generic and allows to implement different semi-Lagrangian schemes. We also test and propose numerical limiters which should improve the robustness of the simulations by diminishing spurious oscillations. We only consider here the 4D drift-kinetic model which is the backbone of the 5D gyrokinetic models and relevant to build a robust and accurate numerical method.
Garain, Sudip K; Chakrabarti, Sandip K
2013-01-01T23:59:59.000Z
We study the spectral and timing properties of a two component advective flow (TCAF) around a black hole by numerical simulation. Several cases have been simulated by varying the Keplerian disk rate and the resulting spectra and lightcurves have been produced for all the cases. The dependence of the spectral states and quasi-periodic oscillation (QPO) frequencies on the flow parameters is discussed. We also find the earlier explanation of arising of QPOs as the resonance between infall time scale and cooling time scale remain valid even for Compton cooling.
Choi, Min-Hyung
Simulation Systems Hongjun Jeon1 Min-Hyung Choi2 Min Hong3 1 Dept. of Electrical and Computer Engineering and trajectories of dynamically simulated entities. Therefore, effective and efficient enforcement and proper describes the formulation and integration of geometric constraints in a dynamic simulation and provides
Nikoleris, Teo
1988-01-01T23:59:59.000Z
NUMERICAL SIMULATION OF THE NON-ISOTHERMAL DEVELOPING FLOXV OF A NONLINEAR VISCOELASTIC FLUID IN A RECTANGULAR CHANNEL A Thesis by TEO NIKOLERIS Submitted to the Graduate College of Texas A&M University in partial fulfillment... developing flow of a nonlinear viscoelas- tic fluid. The temperature dependence of the rheological parameters was imposed using an Arrhenius-like exponential relationship. The flow was creeping, at the early stages of thermal development and wall cooling...
Pham, Van Sang
We present a systematic, multiscale, fully detailed numerical modeling for dynamics of fluid flow and ion transport covering Ohmic, limiting, and overlimiting current regimes in conductance of ion-selective membrane. By ...
t -software package for numerical simulations of radioactive contaminant transport in groundwater
Frolkovic, Peter
in groundwater Peter Frolkovic Michael Lampe Gabriel Wittum September 16, 2005 Abstract The software package r3t or as numerical solution of some groundwater flow model, e.g., the density driven flow problem. The matrix Di = Di
Rothstein, Jonathan
An analysis of superhydrophobic turbulent drag reduction mechanisms using direct numerical October 2009; accepted 22 April 2010; published online 11 June 2010 Superhydrophobic surfaces combine the drag reducing performance of superhydrophobic surfaces in turbulent channel flow. Slip velocities, wall
On the numerical simulation of the instationary free fall of a solid in a fluid.
from meteorology, sedimentology and aerospace engineering to biology. We present a new numerical method], sedimentology [1], aerospace engineering [21] and biology (e.g. models for animal flights [2]). Recently
Three-dimensional numerical manifold method simulations for blocky rock analysis
Shentu, Longfei
2011-01-01T23:59:59.000Z
After decades of development, people realize that there are wider and more various applications of numerical modeling and analysis. However, current feasible software tools cannot satisfy engineering and commercial goals. ...
Numerical Simulation of Enhanced Mixing in Scramjet Combustor Using Ramp, Tabs and Suction Collar
Hwang, Seung-Jae
2011-06-09T23:59:59.000Z
(from Ref. 24) -------------- 17 Fig. 13 Measured and predicted crossflow velocities with ramp (from Ref. 27) ------- 18 Fig. 14 Numerical study of mixing efficiency for the scramjet (from Ref. 30) --------- 19 Fig. 15 Cross-stream velocity vectors... Fig. 13 Measured and predicted crossflow velocities with ramp (from Ref. 27) (Velocity vector plot) 19 a) generated grids b) static pressure contours in the plane of symmetry Fig. 14 Numerical study...
Not Available
2012-02-01T23:59:59.000Z
New code will help accelerate design improvements by providing a high-fidelity simulation tool to study power performance, structural loading, and the interactions between devices in arrays.
Direct numerical simulations of type Ia supernovae flames II: The rayleigh-taylor instability
Bell, J.B.; Day, M.S.; Rendleman, C.A.; Woosley, S.E.; Zingale, M.
2004-01-01T23:59:59.000Z
Weaver, T. A. 1994, in Supernovae, Les Houches, Session LIV,Simulations of Type Ia Supernovae Flames II: The Rayleigh-Subject headings: supernovae: general — white dwarfs —
Direct numerical simulations of type Ia supernovae flames I: The landau-darrieus instability
Bell, J.B.; Day, M.S.; Rendleman, C.A.; Woosley, S.E.; Zingale, M.
2003-01-01T23:59:59.000Z
Simulations of Type Ia Supernovae Flames I: The Landau-Subject headings: supernovae: general — white dwarfs —could occur in Type Ia supernovae (Niemeyer & Woosley 1997),
Godfrey, Brendan B.
2014-01-01T23:59:59.000Z
relativistic plasma drift in EM-PIC code, American Institutebeam multidimensional PIC simulations employing theusing the Particle-In-Cell (PIC) technique in the laboratory
Hindi, Haitham; Prabhakar, Shyam; Fox, John D.; Linscott, Ivan; Teytelman, Dmitri; /SLAC
2011-08-31T23:59:59.000Z
We present a technique for the design and verification of efficient bunch-by-bunch controllers for damping longitudinal multibunch instabilities. The controllers attempt to optimize the use of available feedback amplifier power - one of the most expensive components of a feedback system - and define the limits of the closed loop system performance. Our design technique alternates between analytic computation of single bunch optimal controllers and verification on a multibunch numerical simulator. The simulator uses PEP-II parameters and identifies unstable coupled bunch modes, their growth rates and their damping rates with feedback. The results from the simulator are shown to be in reasonable agreement with analytical calculations based on the single bunch model. The technique is then used to evaluate the performance of a variety of controllers proposed for PEP-II.
Jia, Dongxing 1984-
2012-11-15T23:59:59.000Z
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...
Tourani, Chandraprakash Chandra
2011-01-26T23:59:59.000Z
............................................................................................................ 35 2.1 Hypersonic Air-breathing Propulsion Testing ............................................................. 35 2.2 Nonintrusive Diagnostic Techniques for Scramjet Research & Development ............ 47 2.3 Fuel Injection, Ignition, Flame... of 174,700 cells for highlighting the regions which employ grid packing. ............... 87 Figure 47: Mach number Contours for 2-D Cold Flow Simulation ........................................... 89 Figure 48: Mach number comparison for “Fuel OFF” case...
:,; Abbott, B P; Abbott, R; Abbott, T; Abernathy, M R; Accadia, T; Acernese, F; Ackley, K; Adams, C; Adams, T; Addesso, P; Adhikari, R X; Affeldt, C; Agathos, M; Aggarwal, N; Aguiar, O D; Ain, A; Ajith, P; Alemic, A; Allen, B; Allocca, A; Amariutei, D; Andersen, M; Anderson, R; Anderson, S B; Anderson, W G; Arai, K; Araya, M C; Arceneaux, C; Areeda, J; Aston, S M; Astone, P; Aufmuth, P; Aulbert, C; Austin, L; Aylott, B E; Babak, S; Baker, P T; Ballardin, G; Ballmer, S W; Barayoga, J C; Barbet, M; Barish, B C; Barker, D; Barone, F; Barr, B; Barsotti, L; Barsuglia, M; Barton, M A; Bartos, I; Bassiri, R; Basti, A; Batch, J C; Bauchrowitz, J; Bauer, Th S; Behnke, B; Bejger, M; Beker, M G; Belczynski, C; Bell, A S; Bell, C; Bergmann, G; Bersanetti, D; Bertolini, A; Betzwieser, J; Beyersdorf, P T; Bilenko, I A; Billingsley, G; Birch, J; Biscans, S; Bitossi, M; Bizouard, M A; Black, E; Blackburn, J K; Blackburn, L; Blair, D; Bloemen, S; Blom, M; Bock, O; Bodiya, T P; Boer, M; Bogaert, G; Bogan, C; Bond, C; Bondu, F; Bonelli, L; Bonnand, R; Bork, R; Born, M; Boschi, V; Bose, Sukanta; Bosi, L; Bradaschia, C; Brady, P R; Braginsky, V B; Branchesi, M; Brau, J E; Briant, T; Bridges, D O; Brillet, A; Brinkmann, M; Brisson, V; Brooks, A F; Brown, D A; Brown, D D; Brückner, F; Buchman, S; Bulik, T; Bulten, H J; Buonanno, A; Burman, R; Buskulic, D; Buy, C; Cadonati, L; Cagnoli, G; Bustillo, J Calderón; Calloni, E; Camp, J B; Campsie, P; Cannon, K C; Canuel, B; Cao, J; Capano, C D; Carbognani, F; Carbone, L; Caride, S; Castiglia, A; Caudill, S; Cavaglià, M; Cavalier, F; Cavalieri, R; Celerier, C; Cella, G; Cepeda, C; Cesarini, E; Chakraborty, R; Chalermsongsak, T; Chamberlin, S J; Chao, S; Charlton, P; Chassande-Mottin, E; Chen, X; Chen, Y; Chincarini, A; Chiummo, A; Cho, H S; Chow, J; Christensen, N; Chu, Q; Chua, S S Y; Chung, S; Ciani, G; Clara, F; Clark, J A; Cleva, F; Coccia, E; Cohadon, P -F; Colla, A; Collette, C; Colombini, M; Cominsky, L; Constancio, M; Conte, A; Cook, D; Corbitt, T R; Cordier, M; Cornish, N; Corpuz, A; Corsi, A; Costa, C A; Coughlin, M W; Coughlin, S; Coulon, J -P; Countryman, S; Couvares, P; Coward, D M; Cowart, M; Coyne, D C; Coyne, R; Craig, K; Creighton, J D E; Crowder, S G; Cumming, A; Cunningham, L; Cuoco, E; Dahl, K; Canton, T Dal; Damjanic, M; Danilishin, S L; D'Antonio, S; Danzmann, K; Dattilo, V; Daveloza, H; Davier, M; Davies, G S; Daw, E J; Day, R; Dayanga, T; Debreczeni, G; Degallaix, J; Deléglise, S; Del Pozzo, W; Denker, T; Dent, T; Dereli, H; Dergachev, V; De Rosa, R; DeRosa, R T; DeSalvo, R; Dhurandhar, S; Díaz, M; Di Fiore, L; Di Lieto, A; Di Palma, I; Di Virgilio, A; Donath, A; Donovan, F; Dooley, K L; Doravari, S; Dossa, S; Douglas, R; Downes, T P; Drago, M; Drever, R W P; Driggers, J C; Du, Z; Dwyer, S; Eberle, T; Edo, T; Edwards, M; Effler, A; Eggenstein, H; Ehrens, P; Eichholz, J; Eikenberry, S S; Endr?czi, G; Essick, R; Etzel, T; Evans, M; Evans, T; Factourovich, M; Fafone, V; Fairhurst, S; Fang, Q; Farinon, S; Farr, B; Farr, W M; Favata, M; Fehrmann, H; Fejer, M M; Feldbaum, D; Feroz, F; Ferrante, I; Ferrini, F; Fidecaro, F; Finn, L S; Fiori, I; Fisher, R P; Flaminio, R; Fournier, J -D; Franco, S; Frasca, S; Frasconi, F; Frede, M; Frei, Z; Freise, A; Frey, R; Fricke, T T; Fritschel, P; Frolov, V V; Fulda, P; Fyffe, M; Gair, J; Gammaitoni, L; Gaonkar, S; Garufi, F; Gehrels, N; Gemme, G; Genin, E; Gennai, A; Ghosh, S; Giaime, J A; Giardina, K D; Giazotto, A; Gill, C; Gleason, J; Goetz, E; Goetz, R; Gondan, L; González, G; Gordon, N; Gorodetsky, M L; Gossan, S; Goßler, S; Gouaty, R; Gräf, C; Graff, P B; Granata, M; Grant, A; Gras, S; Gray, C; Greenhalgh, R J S; Gretarsson, A M; Groot, P; Grote, H; Grover, K; Grunewald, S; Guidi, G M; Guido, C; Gushwa, K; Gustafson, E K; Gustafson, R; Hammer, D; Hammond, G; Hanke, M; Hanks, J; Hanna, C; Hanson, J; Harms, J; Harry, G M; Harry, I W; Harstad, E D; Hart, M; Hartman, M T; Haster, C -J; Haughian, K; Heidmann, A; Heintze, M; Heitmann, H; Hello, P; Hemming, G; Hendry, M; Heng, I S; Heptonstall, A W; Heurs, M; Hewitson, M; Hild, S; Hoak, D; Hodge, K A; Holt, K; Hooper, S; Hopkins, P; Hosken, D J; Hough, J; Howell, E J; Hu, Y; Hughey, B; Husa, S; Huttner, S H; Huynh, M; Huynh-Dinh, T; Ingram, D R; Inta, R; Isogai, T; Ivanov, A; Iyer, B R; Izumi, K; Jacobson, M; James, E; Jang, H; Jaranowski, P; Ji, Y; Jiménez-Forteza, F; Johnson, W W; Jones, D I; Jones, R; Jonker, R J G; Ju, L; K, Haris; Kalmus, P; Kalogera, V; Kandhasamy, S; Kang, G; Kanner, J B; Karlen, J; Kasprzack, M; Katsavounidis, E; Katzman, W; Kaufer, H; Kawabe, K; Kawazoe, F; Kéfélian, F; Keiser, G M; Keitel, D; Kelley, D B; Kells, W; Khalaidovski, A; Khalili, F Y; Khazanov, E A; Kim, C; Kim, K; Kim, N; Kim, N G; Kim, Y -M; King, E J; King, P J; Kinzel, D L; Kissel, J S; Klimenko, S; Kline, J; Koehlenbeck, S; Kokeyama, K; Kondrashov, V; Koranda, S; Korth, W Z; Kowalska, I
2014-01-01T23:59:59.000Z
The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational-wave astrophysics communities. The purpose of NINJA is to study the ability to detect gravitational waves emitted from merging binary black holes and recover their parameters with next-generation gravitational-wave observatories. We report here on the results of the second NINJA project, NINJA-2, which employs 60 complete binary black hole hybrid waveforms consisting of a numerical portion modelling the late inspiral, merger, and ringdown stitched to a post-Newtonian portion modelling the early inspiral. In a "blind injection challenge" similar to that conducted in recent LIGO and Virgo science runs, we added 7 hybrid waveforms to two months of data recolored to predictions of Advanced LIGO and Advanced Virgo sensitivity curves during their first observing runs. The resulting data was analyzed by gravitational-wave detection algorithms and 6 of the waveforms were recovered w...
Li Zewen; Zhang Hongchao; Shen Zhonghua; Ni Xiaowu [School of Science, Nanjing University of Science and Technology, Nanjing 210094 (China)
2013-07-21T23:59:59.000Z
Thermal process of 1064 nm millisecond pulsed Nd:YAG laser irradiated silicon was time-resolved temperature measured by an infrared radiation pyrometer, temperature evolutions of the spot center for wide range of laser energy densities were presented. The waveforms of temperature evolution curves contained much information about phase change, melting, solidification and vaporization. An axisymmetric numerical model was established for millisecond laser heating silicon. The transient temperature fields were obtained by using the finite element method. The numerical results of temperature evolutions of the spot center are in good agreement with the experimental results. Furthermore, the axial temperature distributions of the numerical results give a better understanding of the waveforms in the experimental results. The melting threshold, vaporizing threshold, melting duration, and melting depth were better identified by analyzing two kinds of results.
3D-radiation hydro simulations of disk-planet interactions: I. Numerical algorithm and test cases
H. Klahr; W. Kley
2005-10-13T23:59:59.000Z
We study the evolution of an embedded protoplanet in a circumstellar disk using the 3D-Radiation Hydro code TRAMP, and treat the thermodynamics of the gas properly in three dimensions. The primary interest of this work lies in the demonstration and testing of the numerical method. We show how far numerical parameters can influence the simulations of gap opening. We study a standard reference model under various numerical approximations. Then we compare the commonly used locally isothermal approximation to the radiation hydro simulation using an equation for the internal energy. Models with different treatments of the mass accretion process are compared. Often mass accumulates in the Roche lobe of the planet creating a hydrostatic atmosphere around the planet. The gravitational torques induced by the spiral pattern of the disk onto the planet are not strongly affected in the average magnitude, but the short time scale fluctuations are stronger in the radiation hydro models. An interesting result of this work lies in the analysis of the temperature structure around the planet. The most striking effect of treating the thermodynamics properly is the formation of a hot pressure--supported bubble around the planet with a pressure scale height of H/R ~ 0.5 rather than a thin Keplerian circumplanetary accretion disk. We also observe an outflow of gas above and below the planet during the gap opening phase.
Heat transfer coefficients in two-dimensional Yukawa systems (numerical simulations)
Khrustalyov, Yu. V., E-mail: yuri.khrustalyov@gmail.com; Vaulina, O. S. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)
2013-05-15T23:59:59.000Z
New data on heat transfer in two-dimensional Yukawa systems have been obtained. The results of a numerical study of the thermal conductivity for equilibrium systems with parameters close to the conditions of laboratory experiments in dusty plasma are presented. The Green-Kubo relations are used to calculate the heat transfer coefficients. The influence of dissipation (internal friction) on the heat transfer processes in nonideal systems is studied. New approximations are proposed for the thermal conductivity and diffusivity for nonideal dissipative systems. The results obtained are compared with the existing experimental and numerical data.
Modeling and numerical techniques for high-speed digital simulation of nuclear power plants
Wulff, W.; Cheng, H.S.; Mallen, A.N.
1987-01-01T23:59:59.000Z
Conventional computing methods are contrasted with newly developed high-speed and low-cost computing techniques for simulating normal and accidental transients in nuclear power plants. Six principles are formulated for cost-effective high-fidelity simulation with emphasis on modeling of transient two-phase flow coolant dynamics in nuclear reactors. Available computing architectures are characterized. It is shown that the combination of the newly developed modeling and computing principles with the use of existing special-purpose peripheral processors is capable of achieving low-cost and high-speed simulation with high-fidelity and outstanding user convenience, suitable for detailed reactor plant response analyses.
Numerical Integration Numerical Summation
Cohen, Henri
Numerical Integration Numerical Summation Numerical Extrapolation Numerical Recipes for Multiprecision Computations #12;Numerical Integration Numerical Summation Numerical Extrapolation Multiprecision, integration, summation, extrapolation, evaluation of continued fractions, Euler products and sums, complete
An adaptive framework for high-order, mixed-element numerical simulations
Caplan, Philip Claude Delhaye
2014-01-01T23:59:59.000Z
This work builds upon an adaptive simulation framework to allow for mixed-element meshes in two dimensions. Contributions are focused in the area of mesh generation which employs the Lk norm to produce various mesh types. ...
Abd. Rahim, Mohd. Razi
2010-08-26T23:59:59.000Z
This doctoral project dissertation deals with the investigation of simulation/analysis in the product development process of specialized heavy ground vehicle engineering which posts some of the most challenging engineering ...
Assessment of the State-Of-The-Art of Numerical Simulation of Enhanced Geothermal Systems
None
1999-11-01T23:59:59.000Z
The reservoir features of importance in the operation of enhanced geothermal systems are described first (Section 2). The report then reviews existing reservoir simulators developed for application to HDR reservoirs (Section 3), hydrothermal systems (Section 4), and nuclear waste isolation (Section 5), highlighting capabilities relevant to the evaluation and assessment of EGS. The report focuses on simulators that include some representation of flow in fractures, only mentioning other simulators, such as general-purpose programs or groundwater models (Section 6). Following these detailed descriptions, the report summarizes and comments on the simulators (Section 7), and recommends a course of action for further development (Section 8). The references are included in Section 9. Appendix A contains contractual information, including a description of the original and revised scope of work for this study. Appendix B presents comments on the draft report from DOE reviewer(s) and the replies of the authors to those comments. [DJE-2005
Numerical simulation of transient, incongruent vaporization induced by high power laser
Tsai, C.H.
1981-01-01T23:59:59.000Z
A mathematical model and numerical calculations were developed to solve the heat and mass transfer problems specifically for uranum oxide subject to laser irradiation. It can easily be modified for other heat sources or/and other materials. In the uranium-oxygen system, oxygen is the preferentially vaporizing component, and as a result of the finite mobility of oxygen in the solid, an oxygen deficiency is set up near the surface. Because of the bivariant behavior of uranium oxide, the heat transfer problem and the oxygen diffusion problem are coupled and a numerical method of simultaneously solving the two boundary value problems is studied. The temperature dependence of the thermal properties and oxygen diffusivity, as well as the highly ablative effect on the surface, leads to considerable non-linearities in both the governing differential equations and the boundary conditions. Based on the earlier work done in this laboratory by Olstad and Olander on Iron and on Zirconium hydride, the generality of the problem is expanded and the efficiency of the numerical scheme is improved. The finite difference method, along with some advanced numerical techniques, is found to be an efficient way to solve this problem.
Numerical simulation of flow of shear-thinning fluids in corrugated channels
Aiyalur Shankaran, Rohit
2009-05-15T23:59:59.000Z
A numerical study of flow of a shear thinning fluid through a pair of corrugated plates was carried out. The aim of the study was to observe and understand the behavior of the flow of shear thinning fluids through channels were the fluid...
Grilli, Stéphan T.
; La Palma ,Canary Islands, Spain). Subaerial slide scenarios are first defined based on recent slope Volcano (CVV) on La Palma island (Canary Islands, Spain; Fig. 1) has been the object of numerous studies of past large paleo-submarine landslides of O(100 km3 ) volume, around the canary islands, at least
Modeling Computer Viruses MSc Thesis (Afstudeerscriptie)
Amsterdam, University of
Modeling Computer Viruses MSc Thesis (Afstudeerscriptie) written by Luite Menno Pieter van Zelst About half a year ago, Alban Ponse, my thesis supervisor, suggested that the topic of `computer viruses indus- try and the creators of computer viruses. After all, the anti-virus industry stands to lose a lot
NUMERICAL SIMULATIONS OF AIR FLOW AND HEAT TRANSFER VIA PDES By Fei Cao, Luz Angelica Caudillo Transfer via PDEs Fei Cao, Luz Angelica Caudillo-Mata, Natalia Iwanski, Yong Li, Kamran Sadiq, Arturo
Silva, Ramon Alejandro
2013-04-25T23:59:59.000Z
When a microphone array is mounted on a mobile aerial platform, such as an unmanned aerial vehicle (UAV), most existing beamforming methods cannot be used to adequately identify continuous and impulsive ground. Here, numerical simulation results...
Numerical simulations of lab-scale brine-water mixing experiments.
Khalil, Imane; Webb, Stephen Walter
2006-10-01T23:59:59.000Z
Laboratory-scale experiments simulating the injection of fresh water into brine in a Strategic Petroleum Reserve (SPR) cavern were performed at Sandia National Laboratories for various conditions of injection rate and small and large injection tube diameters. The computational fluid dynamic (CFD) code FLUENT was used to simulate these experiments to evaluate the predictive capability of FLUENT for brine-water mixing in an SPR cavern. The data-model comparisons show that FLUENT simulations predict the mixing plume depth reasonably well. Predictions of the near-wall brine concentrations compare very well with the experimental data. The simulated time for the mixing plume to reach the vessel wall was underpredicted for the small injection tubes but reasonable for the large injection tubes. The difference in the time to reach the wall is probably due to the three-dimensional nature of the mixing plume as it spreads out at the air-brine or oil-brine interface. The depth of the mixing plume as it spreads out along the interface was within a factor of 2 of the experimental data. The FLUENT simulation results predict the plume mixing accurately, especially the water concentration when the mixing plume reaches the wall. This parameter value is the most significant feature of the mixing process because it will determine the amount of enhanced leaching at the oil-brine interface.
Numerical Simulation of Combustion and Rotor-Stator Interaction in a Turbine Combustor
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Isvoranu, Dragos D.; Cizmas, Paul G. A.
2003-01-01T23:59:59.000Z
This article presents the development of a numerical algorithm for the computation of flow and combustion in a turbine combustor. The flow and combustion are modeled by the Reynolds-averaged Navier-Stokes equations coupled with the species-conservation equations. The chemistry model used herein is a two-step, global, finite-rate combustion model for methane and combustion gases. The governing equations are written in the strong conservation form and solved using a fully implicit, finite-difference approximation. The gas dynamics and chemistry equations are fully decoupled. A correction technique has been developed to enforce the conservation of mass fractions. The numerical algorithm developed herein has beenmore »used to investigate the flow and combustion in a one-stage turbine combustor.« less
Numerical simulation of flow and heat transfer of internal cooling passage in gas turbine blade
Su, Guoguang
2007-04-25T23:59:59.000Z
for Rectangular Duct (Ar = 4:1) with In-Line V-Shaped Ribs on Leading and Trailing Surfaces ..............................................................................................17 Fig. 3.2 (a) Numerical Grid, (b) Grid Refinement....10 Nusselt Number Ratio Contours on (a) Leading and (b) Trailing Surface for Lower Reynolds Number (Re = 10,000) Cases............................34 Fig. 3.11 Comparison between Calculated and Measured Nusselt Number Ratios...
Kajimura, Y. [Research Institute for Sustainable Humanosphere (RISH), Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Japan Science and Technology Agency (JST), CREST 4-1-8 Hon-chou, Kawaguchi, Saitama 332-0012 (Japan); Matsuda, N.; Hayashida, K.; Maeno, A.; Nakashima, H. [Department of Advanced Energy Engineering Science, Interdisciplinary Graduate school of Engineering Sciences, Kyushu University, Kasugakouen 6-1, Kasuga, Fukuoka 816-580 (Japan)
2008-12-31T23:59:59.000Z
Numerical simulations of plasma behavior in a magnetic nozzle of a Laser-Plasma Driven Nuclear Electric Propulsion System are conducted. The propellant is heated and accelerated by the laser and expanded isotropically. The magnetic nozzle is a combination of solenoidal coils and used to collimate and guide the plasma to produce thrust. Simulation calculations by a three-dimensional hybrid code are conducted to examine the plasma behaviors in the nozzle and to estimate the thrust efficiency. We also estimate a fraction ({alpha}) of plasma particles leaking in the forward (spacecraft) direction. By a combination of a few coils, we could decrease {alpha} value without degrading the thrust efficiency. Finally, the shaped propellant is proposed to increase the thrust efficiency.
Molenkamp, C.R.; Grossman, A.
1999-12-20T23:59:59.000Z
A network of small balloon-borne transponders which gather very high resolution wind and temperature data for use by modern numerical weather predication models has been proposed to improve the reliability of long-range weather forecasts. The global distribution of an array of such transponders is simulated using LLNL's atmospheric parcel transport model (GRANTOUR) with winds supplied by two different general circulation models. An initial study used winds from CCM3 with a horizontal resolution of about 3 degrees in latitude and longitude, and a second study used winds from NOGAPS with a 0.75 degree horizontal resolution. Results from both simulations show that reasonable global coverage can be attained by releasing balloons from an appropriate set of launch sites.
Shlapakovski, Anatoli; Beilin, Leonid; Bliokh, Yuri; Donskoy, Moshe; Krasik, Yakov E. [Physics Department, Technion, Haifa 32000 (Israel); Hadas, Yoav [Department of Applied Physics, Rafael, PO Box 2250, Haifa 31021 (Israel); Schamiloglu, Edl [Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, New Mexico 87131 (United States)
2014-05-07T23:59:59.000Z
Numerical simulations of the process of electromagnetic energy release from a high-power microwave pulse compressor comprising a gas-filled cavity and interference switch were carried out. A microwave plasma discharge in a rectangular waveguide H-plane tee was modeled with the use of the fully electromagnetic particle-in-cell code MAGIC. The gas ionization, plasma evolution, and interaction with RF fields accumulated within the compressor were simulated using different approaches provided by the MAGIC code: particle-in-cell approach accounting for electron-neutral collisions, gas conductivity model based on the concept of mobility, and hybrid modeling. The dependences of the microwave output pulse peak power and waveform on parameters that can be controlled in experiments, such as an external ionization rate, RF field amplitude, and background gas pressure, were investigated.
Numerical simulation: Toward the design of high-efficiency planar perovskite solar cells
Liu, Feng; Zhu, Jun, E-mail: zhujzhu@gmail.com, E-mail: sydai@ipp.ac.cn; Wei, Junfeng; Li, Yi; Lv, Mei [Key Laboratory of Novel Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Yang, Shangfeng [Hefei National Laboratory for Physical Sciences at Microscale, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Zhang, Bing; Yao, Jianxi [State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206 (China); Dai, Songyuan, E-mail: zhujzhu@gmail.com, E-mail: sydai@ipp.ac.cn [Key Laboratory of Novel Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206 (China)
2014-06-23T23:59:59.000Z
Organo-metal halide perovskite solar cells based on planar architecture have been reported to achieve remarkably high power conversion efficiency (PCE, >16%), rendering them highly competitive to the conventional silicon based solar cells. A thorough understanding of the role of each component in solar cells and their effects as a whole is still required for further improvement in PCE. In this work, the planar heterojunction-based perovskite solar cells were simulated with the program AMPS (analysis of microelectronic and photonic structures)-1D. Simulation results revealed a great dependence of PCE on the thickness and defect density of the perovskite layer. Meanwhile, parameters including the work function of the back contact as well as the hole mobility and acceptor density in hole transport materials were identified to significantly influence the performance of the device. Strikingly, an efficiency over 20% was obtained under the moderate simulation conditions.
Pahn, T.; Jonkman, J.; Rolges, R.; Robertson, A.
2012-11-01T23:59:59.000Z
Physically measuring the dynamic responses of wind turbine support structures enables the calculation of the applied loads using an inverse procedure. In this process, inverse means deriving the inputs/forces from the outputs/responses. This paper presents results of a numerical verification of such an inverse load calculation. For this verification, the comprehensive simulation code FAST is used. FAST accounts for the coupled dynamics of wind inflow, aerodynamics, elasticity and turbine controls. Simulations are run using a 5-MW onshore wind turbine model with a tubular tower. Both the applied loads due to the instantaneous wind field and the resulting system responses are known from the simulations. Using the system responses as inputs to the inverse calculation, the applied loads are calculated, which in this case are the rotor thrust forces. These forces are compared to the rotor thrust forces known from the FAST simulations. The results of these comparisons are presented to assess the accuracy of the inverse calculation. To study the influences of turbine controls, load cases in normal operation between cut-in and rated wind speed, near rated wind speed and between rated and cut-out wind speed are chosen. The presented study shows that the inverse load calculation is capable of computing very good estimates of the rotor thrust. The accuracy of the inverse calculation does not depend on the control activity of the wind turbine.
VOL. 19 NO. 1 ACTA METEOROLOGICA SINICA 2005 Numerical Simulation of Wind and Temperature Fields
Thompson, Anne
in the atmosphere boundary layer over urban and its surrounding areas. Urban heat island (UHI) is a well- known that the wind field is affected by the topography and urban heat island. Yang et al. (2003) simulated the winter heat island of Beijing considering the daily changing anthropogenic heat. It is indicated
Numerical Simulation of Orthogonal Cutting using the Material Point John A. Nairn
Nairn, John A.
that can simulate cutting into steady-state chip curling is described. The modeling used ductile fracture cutting as a ductile fracture mechanics prob- lem for a crack propagating in the direction of the tool tip can be used to measure the toughness of ductile materials. The concept is that extrapolation
Vassiliadis, Vassilios S.; Fiorelli, Fabio
2014-05-22T23:59:59.000Z
in the computer aided design of huge scale dynamical systems (e.g. as in the simulation of combustion in a distributed way within an internal combustion engine in the automobile industry). With a proper integration within an optimisation framework, furthermore...
Numerical simulation of flow distribution for pebble bed high temperature gas cooled reactors
Yesilyurt, Gokhan
2004-09-30T23:59:59.000Z
to study the flow past bluff bodies. A suitable CFD code (CFX5.6b) was selected and implemented. Simulation of turbulent transport for the gas through the gaps of the randomly distributed spherical fuel elements (pebbles) was performed. Although there are a...
Lang, Richard Anthony
2004-09-30T23:59:59.000Z
of comminution in a sheared granular material. The model, based on the Discrete Element Method, simulates a layer of 2-D circular grains subjected to normal stress and sheared at constant velocity. An existing code was modified to allow grains to break when...
Jones, Nathan
2012-10-19T23:59:59.000Z
mechanisms is to reduce the computational time needed to simulate a problem. The focus of this work is on the validity of reduced methane-air combustion mechanisms, particularly pertaining to satisfying the entropy inequality. While much of this work involves...
Numerical simulation of the photoisomerization of retinal from the cis to the trans form
Sinha, Indrani
2009-05-15T23:59:59.000Z
systems including ethylene, 2-butene, and stilbene. The cis-trans isomerization is modeled and in each case the results agree well with those obtained from other computational and empirical methods. Next, we use the tight-binding model to simulate...
NUMERICAL SIMULATIONS OF CHROMOSPHERIC ANEMONE JETS ASSOCIATED WITH MOVING MAGNETIC FEATURES
Yang, Liping; He, Jiansen; Tu, Chuanyi; Zhang, Lei [School of Earth and Space Sciences, Peking University, 100871 Beijing (China); Peter, Hardi [Max Planck Institute for Solar System Research, D-37191 Katlenburg-Lindau (Germany); Feng, Xueshang [SIGMA Weather Group, State Key Laboratory for Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, 100871 Beijing (China); Zhang, Shaohua, E-mail: jshept@gmail.com [Institute of Geology and Geophysics, Chinese Academy of Sciences, 100871 Beijing (China)
2013-11-01T23:59:59.000Z
Observations with the space-based solar observatory Hinode show that small-scale magnetic structures in the photosphere are found to be associated with a particular class of jets of plasma in the chromosphere called anemone jets. The goal of our study is to conduct a numerical experiment of such chromospheric anemone jets related to the moving magnetic features (MMFs). We construct a 2.5 dimensional numerical MHD model to describe the process of magnetic reconnection between the MMFs and the pre-existing ambient magnetic field, which is driven by the horizontal motion of the magnetic structure in the photosphere. We include thermal conduction parallel to the magnetic field and optically thin radiative losses in the corona to account for a self-consistent description of the evaporation process during the heating of the plasma due to the reconnection process. The motion of the MMFs leads to the expected jet and our numerical results can reproduce many observed characteristics of chromospheric anemone jets, topologically and quantitatively. As a result of the tearing instability, plasmoids are generated in the reconnection process that are consistent with the observed bright moving blobs in the anemone jets. An increase in the thermal pressure at the base of the jet is also driven by the reconnection, which induces a train of slow-mode shocks propagating upward. These shocks are a secondary effect, and only modulate the outflow of the anemone jet. The jet itself is driven by the energy input due to the reconnection of the MMFs and the ambient magnetic field.
The LIGO Scientific Collaboration; the Virgo Collaboration; the NINJA-2 Collaboration; :; J. Aasi; B. P. Abbott; R. Abbott; T. Abbott; M. R. Abernathy; T. Accadia; F. Acernese; K. Ackley; C. Adams; T. Adams; P. Addesso; R. X. Adhikari; C. Affeldt; M. Agathos; N. Aggarwal; O. D. Aguiar; A. Ain; P. Ajith; A. Alemic; B. Allen; A. Allocca; D. Amariutei; M. Andersen; R. Anderson; S. B. Anderson; W. G. Anderson; K. Arai; M. C. Araya; C. Arceneaux; J. Areeda; S. M. Aston; P. Astone; P. Aufmuth; C. Aulbert; L. Austin; B. E. Aylott; S. Babak; P. T. Baker; G. Ballardin; S. W. Ballmer; J. C. Barayoga; M. Barbet; B. C. Barish; D. Barker; F. Barone; B. Barr; L. Barsotti; M. Barsuglia; M. A. Barton; I. Bartos; R. Bassiri; A. Basti; J. C. Batch; J. Bauchrowitz; Th. S. Bauer; B. Behnke; M. Bejger; M. G. Beker; C. Belczynski; A. S. Bell; C. Bell; G. Bergmann; D. Bersanetti; A. Bertolini; J. Betzwieser; P. T. Beyersdorf; I. A. Bilenko; G. Billingsley; J. Birch; S. Biscans; M. Bitossi; M. A. Bizouard; E. Black; J. K. Blackburn; L. Blackburn; D. Blair; S. Bloemen; M. Blom; O. Bock; T. P. Bodiya; M. Boer; G. Bogaert; C. Bogan; C. Bond; F. Bondu; L. Bonelli; R. Bonnand; R. Bork; M. Born; V. Boschi; Sukanta Bose; L. Bosi; C. Bradaschia; P. R. Brady; V. B. Braginsky; M. Branchesi; J. E. Brau; T. Briant; D. O. Bridges; A. Brillet; M. Brinkmann; V. Brisson; A. F. Brooks; D. A. Brown; D. D. Brown; F. Brückner; S. Buchman; T. Bulik; H. J. Bulten; A. Buonanno; R. Burman; D. Buskulic; C. Buy; L. Cadonati; G. Cagnoli; J. Calderón Bustillo; E. Calloni; J. B. Camp; P. Campsie; K. C. Cannon; B. Canuel; J. Cao; C. D. Capano; F. Carbognani; L. Carbone; S. Caride; A. Castiglia; S. Caudill; M. Cavaglià; F. Cavalier; R. Cavalieri; C. Celerier; G. Cella; C. Cepeda; E. Cesarini; R. Chakraborty; T. Chalermsongsak; S. J. Chamberlin; S. Chao; P. Charlton; E. Chassande-Mottin; X. Chen; Y. Chen; A. Chincarini; A. Chiummo; H. S. Cho; J. Chow; N. Christensen; Q. Chu; S. S. Y. Chua; S. Chung; G. Ciani; F. Clara; J. A. Clark; F. Cleva; E. Coccia; P. -F. Cohadon; A. Colla; C. Collette; M. Colombini; L. Cominsky; M. Constancio Jr.; A. Conte; D. Cook; T. R. Corbitt; M. Cordier; N. Cornish; A. Corpuz; A. Corsi; C. A. Costa; M. W. Coughlin; S. Coughlin; J. -P. Coulon; S. Countryman; P. Couvares; D. M. Coward; M. Cowart; D. C. Coyne; R. Coyne; K. Craig; J. D. E. Creighton; S. G. Crowder; A. Cumming; L. Cunningham; E. Cuoco; K. Dahl; T. Dal Canton; M. Damjanic; S. L. Danilishin; S. D'Antonio; K. Danzmann; V. Dattilo; H. Daveloza; M. Davier; G. S. Davies; E. J. Daw; R. Day; T. Dayanga; G. Debreczeni; J. Degallaix; S. Deléglise; W. Del Pozzo; T. Denker; T. Dent; H. Dereli; V. Dergachev; R. De Rosa; R. T. DeRosa; R. DeSalvo; S. Dhurandhar; M. Díaz; L. Di Fiore; A. Di Lieto; I. Di Palma; A. Di Virgilio; A. Donath; F. Donovan; K. L. Dooley; S. Doravari; S. Dossa; R. Douglas; T. P. Downes; M. Drago; R. W. P. Drever; J. C. Driggers; Z. Du; S. Dwyer; T. Eberle; T. Edo; M. Edwards; A. Effler; H. Eggenstein; P. Ehrens; J. Eichholz; S. S. Eikenberry; G. Endr?czi; R. Essick; T. Etzel; M. Evans; T. Evans; M. Factourovich; V. Fafone; S. Fairhurst; Q. Fang; S. Farinon; B. Farr; W. M. Farr; M. Favata; H. Fehrmann; M. M. Fejer; D. Feldbaum; F. Feroz; I. Ferrante; F. Ferrini; F. Fidecaro; L. S. Finn; I. Fiori; R. P. Fisher; R. Flaminio; J. -D. Fournier; S. Franco; S. Frasca; F. Frasconi; M. Frede; Z. Frei; A. Freise; R. Frey; T. T. Fricke; P. Fritschel; V. V. Frolov; P. Fulda; M. Fyffe; J. Gair; L. Gammaitoni; S. Gaonkar; F. Garufi; N. Gehrels; G. Gemme; E. Genin; A. Gennai; S. Ghosh; J. A. Giaime; K. D. Giardina; A. Giazotto; C. Gill; J. Gleason; E. Goetz; R. Goetz; L. Gondan; G. González; N. Gordon; M. L. Gorodetsky; S. Gossan; S. Goßler; R. Gouaty; C. Gräf; P. B. Graff; M. Granata; A. Grant; S. Gras; C. Gray; R. J. S. Greenhalgh; A. M. Gretarsson; P. Groot; H. Grote; K. Grover; S. Grunewald; G. M. Guidi; C. Guido; K. Gushwa; E. K. Gustafson; R. Gustafson; D. Hammer; G. Hammond; M. Hanke; J. Hanks; C. Hanna; J. Hanson; J. Harms; G. M. Harry; I. W. Harry; E. D. Harstad; M. Hart; M. T. Hartman; C. -J. Haster; K. Haughian; A. Heidmann; M. Heintze; H. Heitmann; P. Hello; G. Hemming; M. Hendry; I. S. Heng; A. W. Heptonstall; M. Heurs; M. Hewitson; S. Hild; D. Hoak; K. A. Hodge; K. Holt; S. Hooper; P. Hopkins; D. J. Hosken; J. Hough; E. J. Howell; Y. Hu; B. Hughey; S. Husa; S. H. Huttner; M. Huynh; T. Huynh-Dinh; D. R. Ingram; R. Inta; T. Isogai; A. Ivanov; B. R. Iyer; K. Izumi; M. Jacobson; E. James; H. Jang; P. Jaranowski; Y. Ji; F. Jiménez-Forteza; W. W. Johnson; D. I. Jones; R. Jones; R. J. G. Jonker; L. Ju; Haris K; P. Kalmus; V. Kalogera; S. Kandhasamy; G. Kang; J. B. Kanner; J. Karlen; M. Kasprzack; E. Katsavounidis; W. Katzman; H. Kaufer; K. Kawabe; F. Kawazoe; F. Kéfélian; G. M. Keiser; D. Keitel; D. B. Kelley; W. Kells; A. Khalaidovski
2014-01-05T23:59:59.000Z
The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational-wave astrophysics communities. The purpose of NINJA is to study the ability to detect gravitational waves emitted from merging binary black holes and recover their parameters with next-generation gravitational-wave observatories. We report here on the results of the second NINJA project, NINJA-2, which employs 60 complete binary black hole hybrid waveforms consisting of a numerical portion modelling the late inspiral, merger, and ringdown stitched to a post-Newtonian portion modelling the early inspiral. In a "blind injection challenge" similar to that conducted in recent LIGO and Virgo science runs, we added 7 hybrid waveforms to two months of data recolored to predictions of Advanced LIGO and Advanced Virgo sensitivity curves during their first observing runs. The resulting data was analyzed by gravitational-wave detection algorithms and 6 of the waveforms were recovered with false alarm rates smaller than 1 in a thousand years. Parameter estimation algorithms were run on each of these waveforms to explore the ability to constrain the masses, component angular momenta and sky position of these waveforms. We also perform a large-scale monte-carlo study to assess the ability to recover each of the 60 hybrid waveforms with early Advanced LIGO and Advanced Virgo sensitivity curves. Our results predict that early Advanced LIGO and Advanced Virgo will have a volume-weighted average sensitive distance of 300Mpc (1Gpc) for $10M_{\\odot}+10M_{\\odot}$ ($50M_{\\odot}+50M_{\\odot}$) binary black hole coalescences. We demonstrate that neglecting the component angular momenta in the waveform models used in matched-filtering will result in a reduction in sensitivity for systems with large component angular momenta. [Abstract abridged for ArXiv, full version in PDF
Grossman, A; Molenkamp, C R
1999-08-25T23:59:59.000Z
A proposal has been made to establish a high density global network of atmospheric micro transponders to record time, temperature, and wind data with time resolution of {le} 1 minute, temperature accuracy of {+-} 1 K, spatial resolution no poorer than {approx}3km horizontally and {approx}0.1km vertically, and 2-D speed accuracy of {le} 1m/s. This data will be used in conjunction with advanced numerical weather prediction models to provide increases in the reliability of long range weather forecasts. Major advances in data collection technology will be required to provide the proposed high-resolution data collection network. Systems studies must be undertaken to determine insertion requirements, spacing, and evolution of the transponder ensemble, which will be used to collect the data. Numerical models which provide realistic global weather pattern simulations must be utilized in order to perform these studies. A global circulation model with a 3{sup o} horizontal resolution has been used for initial simulations of the generation and evolution of transponder distributions. These studies indicate that reasonable global coverage of transponders can be achieved by a launch scenario consisting of the sequential launch of transponders at specified heights from a globally distributed set of launch sites.
Development of Numerical Simulation Capabilities for In Situ Heating of Oil
Office of Scientific and Technical Information (OSTI)
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Numerical simulation of high-speed penetration-perforation dynamics in layered armor shields
Ayzenberg-Stepanenko, Mark
2012-01-01T23:59:59.000Z
Penetration models and calculating algorithms are presented, describing the dynamics and fracture of composite armor shields penetrated by high-speed small arms. A shield considered consists of hard (metal or ceramic) facing and multilayered fabric backing. A simple formula is proved for the projectile residual velocity after perforation of a thin facing. A new plastic-flow jet model is proposed for calculating penetration dynamics in the case of a thick facing of ceramic or metal-ceramic FGM materials. By bringing together the developed models into a calculating algorithm, a computer tool is designed enabling simulations of penetration processes in the above-mentioned shields and analysis of optimization problems. Some results of computer simulation are presented. It is revealed in particular that strength proof of pliable backing can be better as compared with more rigid backing. Comparison of calculations and test data shows sufficient applicability of the models and the tool.
Numerical simulation of high-speed penetration-perforation dynamics in layered armor shields
Mark Ayzenberg-Stepanenko; Grigory Osharovich
2012-03-07T23:59:59.000Z
Penetration models and calculating algorithms are presented, describing the dynamics and fracture of composite armor shields penetrated by high-speed small arms. A shield considered consists of hard (metal or ceramic) facing and multilayered fabric backing. A simple formula is proved for the projectile residual velocity after perforation of a thin facing. A new plastic-flow jet model is proposed for calculating penetration dynamics in the case of a thick facing of ceramic or metal-ceramic FGM materials. By bringing together the developed models into a calculating algorithm, a computer tool is designed enabling simulations of penetration processes in the above-mentioned shields and analysis of optimization problems. Some results of computer simulation are presented. It is revealed in particular that strength proof of pliable backing can be better as compared with more rigid backing. Comparison of calculations and test data shows sufficient applicability of the models and the tool.
Numerical simulations of solar energetic particle event timescales associated with ICMES
Qi, S -Y; Wang, Y
2015-01-01T23:59:59.000Z
Recently, S.W. Kahler studied the solar energetic particle (SEP) event timescales associated with coronal mass ejections (CMEs) from spacecraft data analysis. They obtained different timescales of SEP events, such as TO, the onset time from CME launch to SEP onset, TR, the rise time from onset to half the peak intensity (0.5Ip), and TD, the duration of the SEP intensity above 0.5Ip. In this work, we solve SEPs transport equation considering ICME shocks as energetic particle sources. Our simulations show similar results to Kahler's spacecraft data analysis that the weighted average of TD increases with both CME speed and width. Besides, our simulations show the results which were not achieved from the observation data analysis, i.e., TD is directly dependent on CME speed, but not dependent on CME width.
Numerical simulation of ion charge breeding in electron beam ion source
Zhao, L., E-mail: zhao@far-tech.com; Kim, Jin-Soo [FAR-TECH, Inc., San Diego, California 92122 (United States)] [FAR-TECH, Inc., San Diego, California 92122 (United States)
2014-02-15T23:59:59.000Z
The Electron Beam Ion Source particle-in-cell code (EBIS-PIC) tracks ions in an EBIS electron beam while updating electric potential self-consistently and atomic processes by the Monte Carlo method. Recent improvements to the code are reported in this paper. The ionization module has been improved by using experimental ionization energies and shell effects. The acceptance of injected ions and the emittance of extracted ion beam are calculated by extending EBIS-PIC to the beam line transport region. An EBIS-PIC simulation is performed for a Cs charge-breeding experiment at BNL. The charge state distribution agrees well with experiments, and additional simulation results of radial profiles and velocity space distributions of the trapped ions are presented.
Final Report: A Model Management System for Numerical Simulations of Subsurface Processes
Zachmann, David
2013-10-07T23:59:59.000Z
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.
Numerical Simulation of the Flow of a Power Law Fluid in an Elbow Bend
Kanakamedala, Karthik
2010-07-14T23:59:59.000Z
widely used form of the general constitutive equation is the power law model. The one dimensional power law model during simple shear is given by, ??? = ? ? ? ?? ? where, ??? is the shear stress, ? is the consistency index ? ?? is the rate... institution. I would also like to thank the University for providing the supercomputing facilities which have been very helpful for performing the simulations. vi NOMENCLATURE ? Velocity vector p Hydrodynamic pressure ? Cauchy stress tensor...
Egorov, I., E-mail: egoris@tpu.ru [Institute of High Technology Physics, Tomsk Polytechnic University, 2a Lenin Avenue, Tomsk 634028 (Russian Federation)
2014-06-15T23:59:59.000Z
This paper describes the development of a computation model of a pulsed voltage generator for a repetitive electron accelerator. The model is based on a principle circuit of the generator, supplemented with the parasitics elements of the construction. Verification of the principle model was achieved by comparison of simulation with experimental results, where reasonable agreement was demonstrated for a wide range of generator load resistance.
Cohen, Ofer; Attrill, Gemma D. R.; Wills-Davey, Meredith J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St. Cambridge, MA 02138 (United States); Manchester, Ward B. [Center for Space Environment Modeling, University of Michigan, 2455 Hayward St., Ann Arbor, MI 48109 (United States)
2009-11-01T23:59:59.000Z
On 2009 February 13, a coronal wave-CME-dimming event was observed in quadrature by the Solar Terrestrial Relations Observatory (STEREO) spacecraft. We analyze this event using a three-dimensional, global magnetohydrodynamic model for the solar corona. The numerical simulation is driven and constrained by the observations, and indicates where magnetic reconnection occurs between the expanding CME core and surrounding environment. We focus primarily on the lower corona, extending out to 3 R{sub sun}; this range allows simultaneous comparison with both EUVI and COR1 data. Our simulation produces a diffuse coronal bright front remarkably similar to that observed by STEREO/EUVI at 195 A. It is made up of two components, and is the result of a combination of both wave and non-wave mechanisms. The CME becomes large-scale quite low (< 200 Mm) in the corona. It is not, however, an inherently large-scale event; rather, the expansion is facilitated by magnetic reconnection between the expanding CME core and the surrounding magnetic environment. In support of this, we also find numerous secondary dimmings, many far from the initial CME source region. Relating such dimmings to reconnecting field lines within the simulation provides further evidence that CME expansion leads to the 'opening' of coronal field lines on a global scale. Throughout the CME expansion, the coronal wave maps directly to the CME footprint. Our results suggest that the ongoing debate over the 'true' nature of diffuse coronal waves may be mischaracterized. It appears that both wave and non-wave models are required to explain the observations and understand the complex nature of these events.
Marxen, Olaf, E-mail: olaf.marxen@vki.ac.be [Center for Turbulence Research, Building 500, Stanford University, Stanford, CA 94305-3035 (United States) [Center for Turbulence Research, Building 500, Stanford University, Stanford, CA 94305-3035 (United States); Aeronautics and Aerospace Department, von Karman Institute for Fluid Dynamics, Chaussée de Waterloo, 72, 1640 Rhode-St-Genèse (Belgium); Magin, Thierry E. [Aeronautics and Aerospace Department, von Karman Institute for Fluid Dynamics, Chaussée de Waterloo, 72, 1640 Rhode-St-Genèse (Belgium)] [Aeronautics and Aerospace Department, von Karman Institute for Fluid Dynamics, Chaussée de Waterloo, 72, 1640 Rhode-St-Genèse (Belgium); Shaqfeh, Eric S.G.; Iaccarino, Gianluca [Center for Turbulence Research, Building 500, Stanford University, Stanford, CA 94305-3035 (United States)] [Center for Turbulence Research, Building 500, Stanford University, Stanford, CA 94305-3035 (United States)
2013-12-15T23:59:59.000Z
A new numerical method is presented here that allows to consider chemically reacting gases during the direct numerical simulation of a hypersonic fluid flow. The method comprises the direct coupling of a solver for the fluid mechanical model and a library providing the physio-chemical model. The numerical method for the fluid mechanical model integrates the compressible Navier–Stokes equations using an explicit time advancement scheme and high-order finite differences. This Navier–Stokes code can be applied to the investigation of laminar-turbulent transition and boundary-layer instability. The numerical method for the physio-chemical model provides thermodynamic and transport properties for different gases as well as chemical production rates, while here we exclusively consider a five species air mixture. The new method is verified for a number of test cases at Mach 10, including the one-dimensional high-temperature flow downstream of a normal shock, a hypersonic chemical reacting boundary layer in local thermodynamic equilibrium and a hypersonic reacting boundary layer with finite-rate chemistry. We are able to confirm that the diffusion flux plays an important role for a high-temperature boundary layer in local thermodynamic equilibrium. Moreover, we demonstrate that the flow for a case previously considered as a benchmark for the investigation of non-equilibrium chemistry can be regarded as frozen. Finally, the new method is applied to investigate the effect of finite-rate chemistry on boundary layer instability by considering the downstream evolution of a small-amplitude wave and comparing results with those obtained for a frozen gas as well as a gas in local thermodynamic equilibrium.
Kneafsey, T.; Moridis, G.J.
2011-01-15T23:59:59.000Z
A preserved sample of hydrate-bearing sandstone from the Mount Elbert Test Well was dissociated by depressurization while monitoring the internal temperature of the sample in two locations and the density changes at high spatial resolution using x-ray CT scanning. The sample contained two distinct regions having different porosity and grain size distributions. The hydrate dissociation occurred initially throughout the sample as a result of depressing the pressure below the stability pressure. This initial stage reduced the temperature to the equilibrium point, which was maintained above the ice point. After that, dissociation occurred from the outside in as a result of heat transfer from the controlled temperature bath surrounding the pressure vessel. Numerical modeling of the test using TOUGH+HYDRATE yielded a gas production curve that closely matches the experimentally measured curve.
Choi, Minseok [Division of Applied Mathematics, Brown University, Providence, RI 02912 (United States); Sapsis, Themistoklis P. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Karniadakis, George Em, E-mail: george_karniadakis@brown.edu [Division of Applied Mathematics, Brown University, Providence, RI 02912 (United States)
2014-08-01T23:59:59.000Z
The Karhunen–Lòeve (KL) decomposition provides a low-dimensional representation for random fields as it is optimal in the mean square sense. Although for many stochastic systems of practical interest, described by stochastic partial differential equations (SPDEs), solutions possess this low-dimensional character, they also have a strongly time-dependent form and to this end a fixed-in-time basis may not describe the solution in an efficient way. Motivated by this limitation of standard KL expansion, Sapsis and Lermusiaux (2009) [26] developed the dynamically orthogonal (DO) field equations which allow for the simultaneous evolution of both the spatial basis where uncertainty ‘lives’ but also the stochastic characteristics of uncertainty. Recently, Cheng et al. (2013) [28] introduced an alternative approach, the bi-orthogonal (BO) method, which performs the exact same tasks, i.e. it evolves the spatial basis and the stochastic characteristics of uncertainty. In the current work we examine the relation of the two approaches and we prove theoretically and illustrate numerically their equivalence, in the sense that one method is an exact reformulation of the other. We show this by deriving a linear and invertible transformation matrix described by a matrix differential equation that connects the BO and the DO solutions. We also examine a pathology of the BO equations that occurs when two eigenvalues of the solution cross, resulting in an instantaneous, infinite-speed, internal rotation of the computed spatial basis. We demonstrate that despite the instantaneous duration of the singularity this has important implications on the numerical performance of the BO approach. On the other hand, it is observed that the BO is more stable in nonlinear problems involving a relatively large number of modes. Several examples, linear and nonlinear, are presented to illustrate the DO and BO methods as well as their equivalence.
Hakan Ozaltun & Herman Shen
2011-11-01T23:59:59.000Z
This article presents assessment of the mechanical behavior of U-10wt% Mo (U10Mo) alloy based monolithic fuel plates subject to irradiation. Monolithic, plate-type fuel is a new fuel form being developed for research and test reactors to achieve higher uranium densities within the reactor core to allow the use of low-enriched uranium fuel in high-performance reactors. Identification of the stress/strain characteristics is important for understanding the in-reactor performance of these plate-type fuels. For this work, three distinct cases were considered: (1) fabrication induced residual stresses (2) thermal cycling of fabricated plates; and finally (3) transient mechanical behavior under actual operating conditions. Because the temperatures approach the melting temperature of the cladding during the fabrication and thermal cycling, high temperature material properties were incorporated to improve the accuracy. Once residual stress fields due to fabrication process were identified, solution was used as initial state for the subsequent simulations. For thermal cycling simulation, elasto-plastic material model with thermal creep was constructed and residual stresses caused by the fabrication process were included. For in-service simulation, coupled fluid-thermal-structural interaction was considered. First, temperature field on the plates was calculated and this field was used to compute the thermal stresses. For time dependent mechanical behavior, thermal creep of cladding, volumetric swelling and fission induced creep of the fuel foil were considered. The analysis showed that the stresses evolve very rapidly in the reactor. While swelling of the foil increases the stress of the foil, irradiation induced creep causes stress relaxation.
Numerical Simulation of Earth Pressure on Head Chamber of Shield Machine with FEM
Li Shouju; Kang Chengang [State Key Laboratory of structural analysis for industrial equipment, Dalian University of Technology, Dalian 116023 (China); Sun, Wei [School of Mechanical Engineering, Dalian University of Technology, Dalian 116023 (China); Shangguan Zichang [School of Civil and Hydraulic Engineering, Dalian University of Technology, Dalian 116023 (China); Institute of Civil Engineering, Dalian Fishery University, Dalian 116023 (China)
2010-05-21T23:59:59.000Z
Model parameters of conditioned soils in head chamber of shield machine are determined based on tree-axial compression tests in laboratory. The loads acting on tunneling face are estimated according to static earth pressure principle. Based on Duncan-Chang nonlinear elastic constitutive model, the earth pressures on head chamber of shield machine are simulated in different aperture ratio cases for rotating cutterhead of shield machine. Relationship between pressure transportation factor and aperture ratio of shield machine is proposed by using aggression analysis.
Simulation of surface waves with porous boundaries in a 2-D numerical wave tank
Koo, Weoncheol
1999-01-01T23:59:59.000Z
for the degree of MASTER OF SCIENCE Approved as to style and content by: Moo-Hyu Kim (Chair of Committee) Hamn-Chi g Chen (Member) Robert O. Reid (Member) M. Nied e i ( ead of Departm nt) May 1999 Major Subject: Ocean Engineering ABSTRACT Simulation.... Moo-Hyun Kim for the guidance, assistance and supervision he has shown in completing this thesis. The patience and encouragement he has shown when various problems occurred are much appreciated. I also want to thank Dr. Hamn-Ching Chen...
Watts, C.A.
1993-09-01T23:59:59.000Z
In this dissertation the possibility that chaos and simple determinism are governing the dynamics of reversed field pinch (RFP) plasmas is investigated. To properly assess this possibility, data from both numerical simulations and experiment are analyzed. A large repertoire of nonlinear analysis techniques is used to identify low dimensional chaos in the data. These tools include phase portraits and Poincare sections, correlation dimension, the spectrum of Lyapunov exponents and short term predictability. In addition, nonlinear noise reduction techniques are applied to the experimental data in an attempt to extract any underlying deterministic dynamics. Two model systems are used to simulate the plasma dynamics. These are the DEBS code, which models global RFP dynamics, and the dissipative trapped electron mode (DTEM) model, which models drift wave turbulence. Data from both simulations show strong indications of low dimensional chaos and simple determinism. Experimental date were obtained from the Madison Symmetric Torus RFP and consist of a wide array of both global and local diagnostic signals. None of the signals shows any indication of low dimensional chaos or low simple determinism. Moreover, most of the analysis tools indicate the experimental system is very high dimensional with properties similar to noise. Nonlinear noise reduction is unsuccessful at extracting an underlying deterministic system.
Chang Hyun Baek; Hyesung Kang; Jongsoo Kim; Dongsu Ryu
2005-06-08T23:59:59.000Z
We study thermal-gravitational instability in simplified models for protogalactic halos using three-dimensional hydrodynamic simulations. The simulations followed the evolution of gas with radiative cooling down to T = 10^4 K, background heating, and self-gravity. Then cooled and condensed clouds were identified and their physical properties were examined in detail. During early stage clouds start to form around initial density peaks by thermal instability. Small clouds appear first and they are pressure-bound. Subsequently, the clouds grow through compression by the background pressure as well as gravitational infall. During late stage cloud-cloud collisions become important, and clouds grow mostly through gravitational merging. Gravitationally bound clouds with mass M_c > ~6 X 10^6 Msun are found in the late stage. They are approximately in virial equilibrium and have radius R_c = \\~150 - 200 pc. Those clouds have gained angular momentum through tidal torque as well as merging, so they have large angular momentum with the spin parameter ~ 0.3. The clouds formed in a denser background tend to have smaller spin parameters. We discuss briefly the implications of our results on the formation of protoglobular cluster clouds in protogalactic halos. (abridged)
Numerical magnetohydrodynamic simulations of expanding flux ropes: Influence of boundary driving
Tacke, Thomas; Dreher, Jürgen [Theoretische Physik I, Ruhr-Universität Bochum, Bochum (Germany)] [Theoretische Physik I, Ruhr-Universität Bochum, Bochum (Germany); Sydora, Richard D. [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada)] [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada)
2013-07-15T23:59:59.000Z
The expansion dynamics of a magnetized, current-carrying plasma arch is studied by means of time-dependent ideal MHD simulations. Initial conditions model the setup used in recent laboratory experiments that in turn simulate coronal loops [J. Tenfelde et al., Phys. Plasmas 19, 072513 (2012); E. V. Stenson and P. M. Bellan, Plasma Phys. Controlled Fusion 54, 124017 (2012)]. Boundary conditions of the electric field at the “lower” boundary, intersected by the arch, are chosen such that poloidal magnetic flux is injected into the domain, either localized at the arch footpoints themselves or halfway between them. These conditions are motivated by the tangential electric field expected to exist in the laboratory experiments due to the external circuit that drives the plasma current. The boundary driving is found to systematically enhance the expansion velocity of the plasma arch. While perturbations at the arch footpoints also deform its legs and create characteristic elongated segments, a perturbation between the footpoints tends to push the entire structure upwards, retaining an ellipsoidal shape.
Numerical simulation of coastal flows when solar radiation is blocked by smoke
Molenkamp, C. R.
1989-05-01T23:59:59.000Z
Smoke from fires ignited in a large-scale nuclear exchange would greatly reduce the flux of solar radiation at the ground and lead to rapid cooling over continental regions. Because of its large heat capacity, the ocean would cool more slowly so that a thermal gradient would tend to develop at the continental coastlines. In order to investigate the hypothesis that these thermal gradients would lead to zones of persistent precipitation along the coastlines, a modified version of the Colorado State University Mesoscale Model has been used to simulate the evolution of atmospheric flows for both West and East coasts assuming a moderate westerly synoptic flow of 5 m s/sup /minus/1/. In both cases a layer of fog forms over the ground, effectively limiting the rate of cooling over land. This fog layer grows in height as the atmosphere aloft cools, forming a stratus cloud. Moisture from the ocean surface, mixed vertically into a radiatively cooled atmosphere, causes a cloud layer to form over the ocean as well. With both land and sea covered by clouds, there is no differential cooling, anomalous flow fields, or enhanced precipitation. These simulations also demonstrate the important role of moisture in moderating the initial rate of atmospheric cooling when solar radiation is blocked by smoke.
Tang, Yu-Hang
2013-01-01T23:59:59.000Z
We present a scalable dissipative particle dynamics simulation code, fully implemented on the Graphics Processing Units (GPUs) using a hybrid CUDA/MPI programming model, which achieves 10-30 times speedup on a single GPU over 16 CPU cores and almost linear weak scaling across a thousand nodes. A unified framework is developed within which the efficient generation of the neighbor list and maintaining particle data locality are addressed. Our algorithm generates strictly ordered neighbor lists in parallel, while the construction is deterministic and makes no use of atomic operations or sorting. Such neighbor list leads to optimal data loading efficiency when combined with a two-level particle reordering scheme. A faster in situ generation scheme for Gaussian random numbers is proposed using precomputed binary signatures. We designed custom transcendental functions that are fast and accurate for evaluating the pairwise interaction. The correctness and accuracy of the code is verified through a set of test cases ...
Numerical Simulation of Superfast Shock-Induced Chemical Reaction in Titanium - Silicon Mixture
Zelepugin, S. A. [Dept. for Structural Macrokinetics, Tomsk Scientific Centre, SD RAS, Tomsk, 634021 (Russian Federation); Nikulichev, V. B. [Kyrgyz-Russian Slavonic University, Bishkek, 720000 (Kyrgyzstan); Ivanova, O. V. [Tomsk State University, Tomsk, 634050 (Russian Federation)
2006-07-28T23:59:59.000Z
A phenomenological zeroth-order kinetic model for computations of shock-induced solid-state chemical reactions in porous mixtures is proposed. In the model a porous mixture is considered as a continuous medium whose thermomechanical properties are determined at each time step depending on mass fractions of the components. The kinetic relationships are characterized by a constant rate of chemical transformation under shock wave loading. The heat release due to chemical transformation is introduced in the energy equation. The effect of the dispersity of the mixture components on the reaction rate is taken into account by varying the constants that enter the kinetic model. The results of the numerical computations for porous Ti-Si mixture reflect the fact that the process can be divided into several stages (dynamic compaction, shock-wave propagation, reaction of synthesis). It is shown that an increase in the chemical-reaction rate can give rise to flow regimes in which the unloading wave almost stops.
PROBABILISTIC SIMULATION OF SUBSURFACE FLUID FLOW: A STUDY USING A NUMERICAL SCHEME
Buscheck, Timothy Eric
1980-03-01T23:59:59.000Z
There has been an increasing interest in probabilistic modeling of hydrogeologic systems. The classical approach to groundwater modeling has been deterministic in nature, where individual layers and formations are assumed to be uniformly homogeneous. Even in the case of complex heterogeneous systems, the heterogeneities describe the differences in parameter values between various layers, but not within any individual layer. In a deterministic model a single-number is assigned to each hydrogeologic parameter, given a particular scale of interest. However, physically there is no such entity as a truly uniform and homogeneous unit. Single-number representations or deterministic predictions are subject to uncertainties. The approach used in this work models such uncertainties with probabilistic parameters. The resulting statistical distributions of output variables are analyzed. A numerical algorithm, based on axiomatic principles of probability theory, performs arithmetic operations between probability distributions. Two subroutines are developed from the algorithm and incorporated into the computer program TERZAGI, which solves groundwater flow problems in saturated, multi-dimensional systems. The probabilistic computer program is given the name, PROGRES. The algorithm has been applied to study the following problems: one-dimensional flow through homogeneous media, steady-state and transient flow conditions, one-dimensional flow through heterogeneous media, steady-state and transient flow conditions, and two-dimensional steady-stte flow through heterogeneous media. The results are compared with those available in the literature.
Two-dimensional numerical simulation of a Stirling engine heat exchanger
Ibrahim, M.B. [Cleveland State Univ., OH (United States); Tew, R.C.; Dudenhoefer, J.E. [Lewis Research Center, Cleveland, OH (United States)
1994-09-01T23:59:59.000Z
This paper describes the first phase of an effort to develop multidimensional models of Stirling engine components; the ultimate goal is to model an entire engine working space. More specifically, this paper describes parallel plate and tubular heat exchanger models with emphasis on the central part of the channel (i.e., ignoring hydrodynamic and thermal end effects). The model assumes: Laminar, incompressible flow with constant thermophysical properties. In addition, a constant axial temperature gradient is imposed. The governing equations, describing the model, have been solved Crack-Nicloson finite-difference scheme. Model predictions have been compared with analytical solutions for oscillating/reversing flow and heat transfer in order to check numerical accuracy. The simplifying assumptions will later be relaxed to permit modeling of incompressible, laminar/turbulent flow that occurs in Stirling heat exchanger. Excellent agreement has been obtained for the model predictions with analytical solutions available for both flow in circular tubes and between parallel plates. Also the heat transfer computational results are in good agreement with the heat transfer analytical results for parallel plates.
Wainwright, Carroll L.; Aguirre, Anthony [SCIPP and Department of Physics, University of California, Santa Cruz, CA, 95064 (United States); Johnson, Matthew C. [Department of Physics and Astronomy, York University, Toronto, On, M3J 1P3 (Canada); Peiris, Hiranya V. [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom); Lehner, Luis [Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5 (Canada); Liebling, Steven L., E-mail: cwainwri@ucsc.edu, E-mail: mjohnson@perimeterinstitute.ca, E-mail: h.peiris@ucl.ac.uk, E-mail: aguirre@scipp.ucsc.edu, E-mail: llehner@perimeterinstitute.ca, E-mail: steve.liebling@liu.edu [Department of Physics, Long Island University, Brookville, NY, 11548 (United States)
2014-03-01T23:59:59.000Z
The theory of eternal inflation in an inflaton potential with multiple vacua predicts that our universe is one of many bubble universes nucleating and growing inside an ever-expanding false vacuum. The collision of our bubble with another could provide an important observational signature to test this scenario. We develop and implement an algorithm for accurately computing the cosmological observables arising from bubble collisions directly from the Lagrangian of a single scalar field. We first simulate the collision spacetime by solving Einstein's equations, starting from nucleation and ending at reheating. Taking advantage of the collision's hyperbolic symmetry, the simulations are performed with a 1+1-dimensional fully relativistic code that uses adaptive mesh refinement. We then calculate the comoving curvature perturbation in an open Friedmann-Robertson-Walker universe, which is used to determine the temperature anisotropies of the cosmic microwave background radiation. For a fiducial Lagrangian, the anisotropies are well described by a power law in the cosine of the angular distance from the center of the collision signature. For a given form of the Lagrangian, the resulting observational predictions are inherently statistical due to stochastic elements of the bubble nucleation process. Further uncertainties arise due to our imperfect knowledge about inflationary and pre-recombination physics. We characterize observational predictions by computing the probability distributions over four phenomenological parameters which capture these intrinsic and model uncertainties. This represents the first fully-relativistic set of predictions from an ensemble of scalar field models giving rise to eternal inflation, yielding significant differences from previous non-relativistic approximations. Thus, our results provide a basis for a rigorous confrontation of these theories with cosmological data.
Neeraj Gupta
2008-03-31T23:59:59.000Z
A series of numerical simulations of carbon dioxide (CO{sub 2}) injection were conducted as part of a program to assess the potential for geologic sequestration in deep geologic reservoirs (the Rose Run and Copper Ridge formations), at the American Electric Power (AEP) Mountaineer Power Plant outside of New Haven, West Virginia. The simulations were executed using the H{sub 2}O-CO{sub 2}-NaCl operational mode of the Subsurface Transport Over Multiple Phases (STOMP) simulator (White and Oostrom, 2006). The objective of the Rose Run formation modeling was to predict CO{sub 2} injection rates using data from the core analysis conducted on the samples. A systematic screening procedure was applied to the Ohio River Valley CO{sub 2} storage site utilizing the Features, Elements, and Processes (FEP) database for geological storage of CO{sub 2} (Savage et al., 2004). The objective of the screening was to identify potential risk categories for the long-term geological storage of CO{sub 2} at the Mountaineer Power Plant in New Haven, West Virginia. Over 130 FEPs in seven main classes were assessed for the project based on site characterization information gathered in a geological background study, testing in a deep well drilled on the site, and general site conditions. In evaluating the database, it was apparent that many of the items were not applicable to the Mountaineer site based its geologic framework and environmental setting. Nine FEPs were identified for further consideration for the site. These FEPs generally fell into categories related to variations in subsurface geology, well completion materials, and the behavior of CO{sub 2} in the subsurface. Results from the screening were used to provide guidance on injection system design, developing a monitoring program, performing reservoir simulations, and other risk assessment efforts. Initial work indicates that the significant FEPs may be accounted for by focusing the storage program on these potential issues. The screening method was also useful in identifying unnecessary items that were not significant given the site-specific geology and proposed scale of the Ohio River Valley CO{sub 2} Storage Project. Overall, the FEP database approach provides a comprehensive methodology for assessing potential risk for a practical CO{sub 2} storage application. An integrated numerical fate and transport model was developed to enable risk and consequence assessment at field scale. Results show that such an integrated modeling effort would be helpful in meeting the project objectives (such as site characterization, engineering, permitting, monitoring and closure) during different stages. A reservoir-scale numerical model was extended further to develop an integrated assessment framework which can address the risk and consequence assessment, monitoring network design and permitting guidance needs. The method was used to simulate sequestration of CO{sub 2} in moderate quantities at the Mountaineer Power Plant. Results indicate that at the relatively low injection volumes planned for pilot scale demonstration at this site, the risks involved are minor to negligible, owing to a thick, low permeability caprock and overburden zones. Such integrated modeling approaches coupled with risk and consequence assessment modeling are valuable to project implementation, permitting, monitoring as well as site closure.
Numerical simulation of the plasma current quench following a disruptive energy loss
Strickler, D.J.; Peng, Y.K.M.; Holmes, J.A.; Miller, J.B.; Rothe, K.E.
1983-11-01T23:59:59.000Z
The plasma electromagnetic interaction with poloidal field coils and nearby passive conductor loops during the current quench following a disruptive loss of plasma energy is simulated. By solving a differential/algebraic system consisting of a set of circuit equations (including the plasma circuit) coupled to a plasma energy balance equation and an equilibrium condition, the electromagnetic consequences of an abrupt thermal quench are observed. Limiters on the small and large major radium sides of the plasma are assumed to define the plasma cross section. The presence of good conductors near the plasma and a small initial distance (i.e., 5 to 10% of the plasma minor radius) between the plasma edge and an inboard limiter are shown to lead to long current decay times. For a plasma with an initial major radius R/sub o/ = 4.3 m, aspect ratio A = 3.6, and current I/sub P/ = 4.0 MA, introducing nearby passive conductors lengthens the current decay from milliseconds to hundreds of milliseconds.
Wagner, Hannes [Department of Solar Energy, Institute Solid-State Physics, Leibniz University of Hannover, Appelstr. 2, 30167 Hannover (Germany); ARC Photovoltaics Centre of Excellence, University of New South Wales (UNSW), Sydney, NSW 2052 (Australia); Ohrdes, Tobias [Institute for Solar Energy Research Hamelin (ISFH), 31860 Emmerthal (Germany); Dastgheib-Shirazi, Amir [Div. Photovoltaics, Department of Physics, University of Konstanz, 78457 Konstanz (Germany); Puthen-Veettil, Binesh; König, Dirk [ARC Photovoltaics Centre of Excellence, University of New South Wales (UNSW), Sydney, NSW 2052 (Australia); Altermatt, Pietro P. [Department of Solar Energy, Institute Solid-State Physics, Leibniz University of Hannover, Appelstr. 2, 30167 Hannover (Germany)
2014-01-28T23:59:59.000Z
The performance of passivated emitter and rear (PERC) solar cells made of p-type Si wafers is often limited by recombination in the phosphorus-doped emitter. To overcome this limitation, a realistic PERC solar cell is simulated, whereby the conventional phosphorus-doped emitter is replaced by a thin, crystalline gallium phosphide (GaP) layer. The resulting GaP/Si PERC cell is compared to Si PERC cells, which have (i) a standard POCl{sub 3} diffused emitter, (ii) a solid-state diffused emitter, or (iii) a high efficiency ion-implanted emitter. The maximum efficiencies for these realistic PERC cells are between 20.5% and 21.2% for the phosphorus-doped emitters (i)–(iii), and up to 21.6% for the GaP emitter. The major advantage of this GaP hetero-emitter is a significantly reduced recombination loss, resulting in a higher V{sub oc}. This is so because the high valence band offset between GaP and Si acts as a nearly ideal minority carrier blocker. This effect is comparable to amorphous Si. However, the GaP layer can be contacted with metal fingers like crystalline Si, so no conductive oxide is necessary. Compared to the conventional PERC structure, the GaP/Si PERC cell requires a lower Si base doping density, which reduces the impact of the boron-oxygen complexes. Despite the lower base doping, fewer rear local contacts are necessary. This is so because the GaP emitter shows reduced recombination, leading to a higher minority electron density in the base and, in turn, to a higher base conductivity.
Modeling-Computer Simulations At Long Valley Caldera Geothermal Area
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a gHigh Plains WindInformation Mississippi's 3rdMitsubishi Acciona
Modeling-Computer Simulations At Long Valley Caldera Geothermal Area
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a gHigh Plains WindInformation Mississippi's 3rdMitsubishi Acciona(Tempel, Et Al., 2011) | Open
Modeling-Computer Simulations At Valles Caldera - Redondo Geothermal Area
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a gHigh Plains WindInformation Mississippi's 3rdMitsubishi Acciona(Tempel, Et Al.,
Modeling-Computer Simulations At Dixie Valley Geothermal Area...
that created the model did a run that took about 15 hours on a pentium-4 processor running at 3 GHz with 1.7 Gbyte of RAM being used. The model revealed an electrical structure...
Modeling-Computer Simulations At Long Valley Caldera Geothermal...
Deformation of the Long Valley Caldera, California: Inferences from Measurements from 1988 to 2001 David P. Hill, John O. Langbein, Stephanie Prejean (2003) Relations Between...
Modeling-Computer Simulations At Long Valley Caldera Geothermal...
surrounding a vertically dipping prolate spheroid source during an active period of time-dependent deformation between 1995 and 2000 at Long Valley caldera. We model a rapid...
Modeling-Computer Simulations At San Juan Volcanic Field Area...
Juan Basin Since Late Cretaceous Times And Its Relationship To San Juan Mountains Thermal Sources Additional References Retrieved from "http:en.openei.orgwindex.php?titleModel...
Modeling-Computer Simulations At Long Valley Caldera Geothermal...
ranging from 240 to 273C, then flow laterally to the east and mix with cool groundwater that infiltrate and recharge the system along ring fractures and faults (an...
Modeling-Computer Simulations At Valles Caldera - Redondo Geothermal...
Keiiti Aki, Michael C. Fehler (1995) A Shallow Attenuating Anomaly Inside The Ring Fracture Of The Valles Caldera, New Mexico Additional References Retrieved from "http:...
Modeling-Computer Simulations At Walker-Lane Transitional Zone...
previous seismic experiments and earthquake-monitoring projects, and data donated from mining, geothermal, and petroleum companies. We also collected (May 2002 and August 2004) two...
Modeling-Computer Simulations At Valles Caldera - Redondo Geothermal...
volcanics, and the basement sections, respectively (Fig. 8). Although correlation with well data was done whenever possible, there is some uncertainty to the model because of...
Modeling-Computer Simulations At Valles Caldera - Sulphur Springs...
volcanics, and the basement sections, respectively (Fig. 8). Although correlation with well data was done whenever possible, there is some uncertainty to the model because of...
Modeling-Computer Simulations (Laney, 2005) | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia: EnergySalton Sea
Modeling-Computer Simulations (Lewicki & Oldenburg, 2004) | Open Energy
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia: EnergySalton SeaInformation
Modeling-Computer Simulations (Ozkocak, 1985) | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia: EnergySalton
Modeling-Computer Simulations (Ranalli & Rybach, 2005) | Open Energy
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia: EnergySaltonInformation
Modeling-Computer Simulations (Walker, Et Al., 2005) | Open Energy
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia: EnergySaltonInformationInformation
Modeling-Computer Simulations At Central Nevada Seismic Zone Region
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003) | Open Energy
Modeling-Computer Simulations At Central Nevada Seismic Zone Region
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003) | Open
Modeling-Computer Simulations At Dixie Valley Geothermal Area (Blackwell,
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003) | OpenEtEt Al.,
Modeling-Computer Simulations At Dixie Valley Geothermal Area (Wannamaker,
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003) | OpenEtEtEt Al.,
Modeling-Computer Simulations At Long Valley Caldera Geothermal Area
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003)
Modeling-Computer Simulations At Long Valley Caldera Geothermal Area
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003)(Farrar, Et Al.,
Modeling-Computer Simulations At Long Valley Caldera Geothermal Area
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003)(Farrar, Et
Modeling-Computer Simulations At Valles Caldera - Redondo Geothermal Area
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al.,| OpenOpen Energy2008)
Modeling-Computer Simulations At Valles Caldera - Sulphur Springs
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al.,| OpenOpen
Modeling-Computer Simulations At Valles Caldera - Sulphur Springs
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al.,| OpenOpenGeothermal Area
Modeling-Computer Simulations At Yellowstone Region (Laney, 2005) | Open
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al.,|(Pritchett, 2004)
Modeling-Computer Simulations At Fenton Hill HDR Geothermal Area...
Discrete Fractures Using GEOCRACK Daniel Swenson, Robert DuTeau, Timothy Sprecker (1995) Modeling Flow in a Jointed Geothermal Reservoir Donald W. Brown (1994) Summary of...
Modeling-Computer Simulations At Fenton Hill HDR Geothermal Area...
24 potential sites for EGS development across the U.S., as well as modeling of the representative geologic systems in which promising EGS sites occur. References Fraser Goff,...
Modeling-Computer Simulations At White Mountains Area (Goff ...
24 potential sites for EGS development across the U.S., as well as modeling of the representative geologic systems in which promising EGS sites occur. References Fraser Goff,...
Modeling-Computer Simulations At Long Valley Caldera Geothermal...
using modeled solutions for a flow system consisting of a rock matrix with finite hydraulic conductivity cut by a steeply dipping fracture with infinite hydraulic conductivity....
Modeling-Computer Simulations At Central Nevada Seismic Zone...
systems References D. D. Blackwell, K. W. Wisian, M. C. Richards, Mark Leidig, Richard Smith, Jason McKenna (2003) Geothermal Resource Analysis And Structure Of Basin And Range...
Modeling-Computer Simulations At Northern Basin & Range Region...
systems References D. D. Blackwell, K. W. Wisian, M. C. Richards, Mark Leidig, Richard Smith, Jason McKenna (2003) Geothermal Resource Analysis And Structure Of Basin And Range...
Modeling-Computer Simulations At Nw Basin & Range Region (Blackwell...
systems References D. D. Blackwell, K. W. Wisian, M. C. Richards, Mark Leidig, Richard Smith, Jason McKenna (2003) Geothermal Resource Analysis And Structure Of Basin And Range...
Modeling-Computer Simulations At Dixie Valley Geothermal Area...
vein structure associated with ore deposits. References David D. Blackwell, Richard P. Smith, Al Waibel, Maria C. Richards, Patrick Stepp (2009) Why Basin and Range Systems are...
Modeling-Computer Simulations At Dixie Valley Geothermal Area...
springs, and fumaroles. These samples were analyzed for noble gas abundances and their helium isotropic compositions. It was found that the geothermal fluids range from 0.70 to...
Moridis, George J.; Collett, Timothy S.; Dallimore, Scott R.; Satoh, Tohru; Hancock, Stephen; Weatherill, Brian
2002-03-22T23:59:59.000Z
The Mallik site represents an onshore permafrost-associated gas hydrate accumulation in the Mackenzie Delta, Northwest Territories, Canada. An 1150 m deep gas hydrate research well was drilled at the site in 1998. The objective of this study is the analysis of various gas production scenarios from several gas-hydrate-bearing zones at the Mallik site. The TOUGH2 general-purpose simulator with the EOSHYDR2 module were used for the analysis. EOSHYDR2 is designed to model the non-isothermal CH{sub 4} (methane) release, phase behavior and flow under conditions typical of methane-hydrate deposits by solving the coupled equations of mass and heat balance, and can describe any combination of gas hydrate dissociation mechanisms. Numerical simulations indicated that significant gas hydrate production at the Mallik site was possible by drawing down the pressure on a thin free-gas zone at the base of the hydrate stability field. Gas hydrate zones with underlying aquifers yielded significant gas production entirely from dissociated gas hydrate, but large amounts of produced water. Lithologically isolated gas-hydrate-bearing reservoirs with no underlying free gas or water zones, and gas-hydrate saturations of at least 50% were also studied. In these cases, it was assumed that thermal stimulation by circulating hot water in the well was the method used to induce dissociation. Sensitivity studies indicated that the methane release from the hydrate accumulations increases with gas-hydrate saturation, the initial formation temperature, the temperature of the circulating water in the well, and the formation thermal conductivity. Methane production appears to be less sensitive to the rock and hydrate specific heat and permeability of the formation.
Rafa, S. Molins; Trebotich, D.; Steefel, C. I.; Shen, C.
2012-02-01T23:59:59.000Z
The scale-dependence of geochemical reaction rates hinders their use in continuum scale models intended for the interpretation and prediction of chemical fate and transport in subsurface environments such as those considered for geologic sequestration of CO{sub 2}. Processes that take place at the pore scale, especially those involving mass transport limitations to reactive surfaces, may contribute to the discrepancy commonly observed between laboratory-determined and continuum-scale or field rates. Here, the dependence of mineral dissolution rates on the pore structure of the porous media is investigated by means of pore scale modeling of flow and multicomponent reactive transport. The pore scale model is comprised of high performance simulation tools and algorithms for incompressible flow and conservative transport combined with a general-purpose multicomponent geochemical reaction code. The model performs direct numerical simulation of reactive transport based on an operator-splitting approach to coupling transport and reactions. The approach is validated with a Poiseuille flow single-pore experiment and verified with an equivalent 1D continuum-scale model of a capillary tube packed with calcite spheres. Using the case of calcite dissolution as an example, the high resolution model is used to demonstrate that non-uniformity in the flow field at the pore scale has the effect of decreasing the overall reactivity of the system, even when systems with identical reactive surface area are considered. The effect becomes more pronounced as the heterogeneity of the reactive grain packing increases, particularly where the flow slows sufficiently such that the solution approaches equilibrium locally and the average rate becomes transport-limited.
Kwon, Kyung [Tuskegee Univ., Tuskegee, AL (United States); Fan, Liang-Shih [The Ohio State Univ., Columbus, OH (United States); Zhou, Qiang [The Ohio State Univ., Columbus, OH (United States); Yang, Hui [The Ohio State Univ., Columbus, OH (United States)
2014-09-30T23:59:59.000Z
A new and efficient direct numerical method with second-order convergence accuracy was developed for fully resolved simulations of incompressible viscous flows laden with rigid particles. The method combines the state-of-the-art immersed boundary method (IBM), the multi-direct forcing method, and the lattice Boltzmann method (LBM). First, the multi-direct forcing method is adopted in the improved IBM to better approximate the no-slip/no-penetration (ns/np) condition on the surface of particles. Second, a slight retraction of the Lagrangian grid from the surface towards the interior of particles with a fraction of the Eulerian grid spacing helps increase the convergence accuracy of the method. An over-relaxation technique in the procedure of multi-direct forcing method and the classical fourth order Runge-Kutta scheme in the coupled fluid-particle interaction were applied. The use of the classical fourth order Runge-Kutta scheme helps the overall IB-LBM achieve the second order accuracy and provides more accurate predictions of the translational and rotational motion of particles. The preexistent code with the first-order convergence rate is updated so that the updated new code can resolve the translational and rotational motion of particles with the second-order convergence rate. The updated code has been validated with several benchmark applications. The efficiency of IBM and thus the efficiency of IB-LBM were improved by reducing the number of the Lagragian markers on particles by using a new formula for the number of Lagrangian markers on particle surfaces. The immersed boundary-lattice Boltzmann method (IBLBM) has been shown to predict correctly the angular velocity of a particle. Prior to examining drag force exerted on a cluster of particles, the updated IB-LBM code along with the new formula for the number of Lagrangian markers has been further validated by solving several theoretical problems. Moreover, the unsteadiness of the drag force is examined when a fluid is accelerated from rest by a constant average pressure gradient toward a steady Stokes flow. The simulation results agree well with the theories for the short- and long-time behavior of the drag force. Flows through non-rotational and rotational spheres in simple cubic arrays and random arrays are simulated over the entire range of packing fractions, and both low and moderate particle Reynolds numbers to compare the simulated results with the literature results and develop a new drag force formula, a new lift force formula, and a new torque formula. Random arrays of solid particles in fluids are generated with Monte Carlo procedure and Zinchenko's method to avoid crystallization of solid particles over high solid volume fractions. A new drag force formula was developed with extensive simulated results to be closely applicable to real processes over the entire range of packing fractions and both low and moderate particle Reynolds numbers. The simulation results indicate that the drag force is barely affected by rotational Reynolds numbers. Drag force is basically unchanged as the angle of the rotating axis varies.
Popovych, Roman
1395 Numerical Simulation of Replacing Oil by Water in a Scale-Invariant Porous Medium Ekaterina P. KUROCHKINA with 2563 grid in spatial variables. 1 Introduction The interface of oil displaced by water is unstable a significant influence on the transport of water and oil. The permeability heterogenei- ty is often identified
Frey, Pascal
method to study the bubble behaviour at the free surface of a large three-dimensional gas fluidized bed. Measurements were carried out to determine the effects of bed height and excess air velocity on the bubbleNumerical simulation of the water bubble rising in a liquid column using the combination of level
Fast, J.D.; O'Steen, B.L.
1992-01-01T23:59:59.000Z
An important aspect of the US Department of Energy's Atmospheric Studies in Complex Terrain (ASCOT) program is the development and evaluation of numerical models that predict transport and diffusion of pollutants in complex terrain. Operational mesoscale modeling of the transport of pollutants in complex terrain will become increasingly practical as computational costs decrease and additional data from high-resolution remote sensing instrumentation networks become available during the 1990s. Four-dimensional data assimilation (4DDA) techniques are receiving a great deal of attention recently not only to improve the initial conditions of mesoscale forecast models, but to create high-quality four-dimensional mesoscale analysis fields that can be used as input to air-quality models. In this study, a four-dimensional data assimilation technique based on Newtonian relaxation is incorporated into the Colorado State University (CSU) Regional Atmospheric Modeling System (RAMS) and evaluated using data taken from one experiment of the 1991 ASCOT field study along the front range of the Rockies in Colorado. The main objective of this study is to compare the observed surface concentrations with those predicted by a Lagrangian particle dispersion model and to demonstrate the effect of data assimilation on the simulated plume. In contrast to pervious studies in which the smallest horizontal grid spacing was 10 km (Stauffer and Seaman, 1991) and 8 km (Yamada and Hermi, 1991), data assimilation is applied in this study to domains with a horizontal grid spacing as small as 1 km.
Fast, J.D.; O`Steen, B.L.
1992-11-01T23:59:59.000Z
An important aspect of the US Department of Energy`s Atmospheric Studies in Complex Terrain (ASCOT) program is the development and evaluation of numerical models that predict transport and diffusion of pollutants in complex terrain. Operational mesoscale modeling of the transport of pollutants in complex terrain will become increasingly practical as computational costs decrease and additional data from high-resolution remote sensing instrumentation networks become available during the 1990s. Four-dimensional data assimilation (4DDA) techniques are receiving a great deal of attention recently not only to improve the initial conditions of mesoscale forecast models, but to create high-quality four-dimensional mesoscale analysis fields that can be used as input to air-quality models. In this study, a four-dimensional data assimilation technique based on Newtonian relaxation is incorporated into the Colorado State University (CSU) Regional Atmospheric Modeling System (RAMS) and evaluated using data taken from one experiment of the 1991 ASCOT field study along the front range of the Rockies in Colorado. The main objective of this study is to compare the observed surface concentrations with those predicted by a Lagrangian particle dispersion model and to demonstrate the effect of data assimilation on the simulated plume. In contrast to pervious studies in which the smallest horizontal grid spacing was 10 km (Stauffer and Seaman, 1991) and 8 km (Yamada and Hermi, 1991), data assimilation is applied in this study to domains with a horizontal grid spacing as small as 1 km.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Schilling, Oleg; Mueschke, Nicholas J.
2010-10-18T23:59:59.000Z
Data from a 1152X760X1280 direct numerical simulation (DNS) of a transitional Rayleigh-Taylor mixing layer modeled after a small Atwood number water channel experiment is used to comprehensively investigate the structure of mean and turbulent transport and mixing. The simulation had physical parameters and initial conditions approximating those in the experiment. The budgets of the mean vertical momentum, heavy-fluid mass fraction, turbulent kinetic energy, turbulent kinetic energy dissipation rate, heavy-fluid mass fraction variance, and heavy-fluid mass fraction variance dissipation rate equations are constructed using Reynolds averaging applied to the DNS data. The relative importance of mean and turbulent production, turbulent dissipationmore »and destruction, and turbulent transport are investigated as a function of Reynolds number and across the mixing layer to provide insight into the flow dynamics not presently available from experiments. The analysis of the budgets supports the assumption for small Atwood number, Rayleigh/Taylor driven flows that the principal transport mechanisms are buoyancy production, turbulent production, turbulent dissipation, and turbulent diffusion (shear and mean field production are negligible). As the Reynolds number increases, the turbulent production in the turbulent kinetic energy dissipation rate equation becomes the dominant production term, while the buoyancy production plateaus. Distinctions between momentum and scalar transport are also noted, where the turbulent kinetic energy and its dissipation rate both grow in time and are peaked near the center plane of the mixing layer, while the heavy-fluid mass fraction variance and its dissipation rate initially grow and then begin to decrease as mixing progresses and reduces density fluctuations. All terms in the transport equations generally grow or decay, with no qualitative change in their profile, except for the pressure flux contribution to the total turbulent kinetic energy flux, which changes sign early in time (a countergradient effect). The production-to-dissipation ratios corresponding to the turbulent kinetic energy and heavy-fluid mass fraction variance are large and vary strongly at small evolution times, decrease with time, and nearly asymptote as the flow enters a self-similar regime. The late-time turbulent kinetic energy production-to-dissipation ratio is larger than observed in shear-driven turbulent flows. The order of magnitude estimates of the terms in the transport equations are shown to be consistent with the DNS at late-time, and also confirms both the dominant terms and their evolutionary behavior. These results are useful for identifying the dynamically important terms requiring closure, and assessing the accuracy of the predictions of Reynolds-averaged Navier-Stokes and large-eddy simulation models of turbulent transport and mixing in transitional Rayleigh-Taylor instability-generated flow.« less
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Schilling, Oleg [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Mueschke, Nicholas J. [Texas A and M Univ., College Station, TX (United States)
2010-01-01T23:59:59.000Z
Data from a 1152X760X1280 direct numerical simulation (DNS) of a transitional Rayleigh-Taylor mixing layer modeled after a small Atwood number water channel experiment is used to comprehensively investigate the structure of mean and turbulent transport and mixing. The simulation had physical parameters and initial conditions approximating those in the experiment. The budgets of the mean vertical momentum, heavy-fluid mass fraction, turbulent kinetic energy, turbulent kinetic energy dissipation rate, heavy-fluid mass fraction variance, and heavy-fluid mass fraction variance dissipation rate equations are constructed using Reynolds averaging applied to the DNS data. The relative importance of mean and turbulent production, turbulent dissipation and destruction, and turbulent transport are investigated as a function of Reynolds number and across the mixing layer to provide insight into the flow dynamics not presently available from experiments. The analysis of the budgets supports the assumption for small Atwood number, Rayleigh/Taylor driven flows that the principal transport mechanisms are buoyancy production, turbulent production, turbulent dissipation, and turbulent diffusion (shear and mean field production are negligible). As the Reynolds number increases, the turbulent production in the turbulent kinetic energy dissipation rate equation becomes the dominant production term, while the buoyancy production plateaus. Distinctions between momentum and scalar transport are also noted, where the turbulent kinetic energy and its dissipation rate both grow in time and are peaked near the center plane of the mixing layer, while the heavy-fluid mass fraction variance and its dissipation rate initially grow and then begin to decrease as mixing progresses and reduces density fluctuations. All terms in the transport equations generally grow or decay, with no qualitative change in their profile, except for the pressure flux contribution to the total turbulent kinetic energy flux, which changes sign early in time (a countergradient effect). The production-to-dissipation ratios corresponding to the turbulent kinetic energy and heavy-fluid mass fraction variance are large and vary strongly at small evolution times, decrease with time, and nearly asymptote as the flow enters a self-similar regime. The late-time turbulent kinetic energy production-to-dissipation ratio is larger than observed in shear-driven turbulent flows. The order of magnitude estimates of the terms in the transport equations are shown to be consistent with the DNS at late-time, and also confirms both the dominant terms and their evolutionary behavior. These results are useful for identifying the dynamically important terms requiring closure, and assessing the accuracy of the predictions of Reynolds-averaged Navier-Stokes and large-eddy simulation models of turbulent transport and mixing in transitional Rayleigh-Taylor instability-generated flow.
Michael Boyle; Alessandra Buonanno; Lawrence E. Kidder; Abdul H. Mroué; Yi Pan; Harald P. Pfeiffer; Mark A. Scheel
2008-10-06T23:59:59.000Z
Expressions for the gravitational wave (GW) energy flux and center-of-mass energy of a compact binary are integral building blocks of post-Newtonian (PN) waveforms. In this paper, we compute the GW energy flux and GW frequency derivative from a highly accurate numerical simulation of an equal-mass, non-spinning black hole binary. We also estimate the (derivative of the) center-of-mass energy from the simulation by assuming energy balance. We compare these quantities with the predictions of various PN approximants (adiabatic Taylor and Pade models; non-adiabatic effective-one-body (EOB) models). We find that Pade summation of the energy flux does not accelerate the convergence of the flux series; nevertheless, the Pade flux is markedly closer to the numerical result for the whole range of the simulation (about 30 GW cycles). Taylor and Pade models overestimate the increase in flux and frequency derivative close to merger, whereas EOB models reproduce more faithfully the shape of and are closer to the numerical flux, frequency derivative and derivative of energy. We also compare the GW phase of the numerical simulation with Pade and EOB models. Matching numerical and untuned 3.5 PN order waveforms, we find that the phase difference accumulated until $M \\omega = 0.1$ is -0.12 radians for Pade approximants, and 0.50 (0.45) radians for an EOB approximant with Keplerian (non-Keplerian) flux. We fit free parameters within the EOB models to minimize the phase difference, and confirm degeneracies among these parameters. By tuning pseudo 4PN order coefficients in the radial potential or in the flux, or, if present, the location of the pole in the flux, we find that the accumulated phase difference can be reduced - if desired - to much less than the estimated numerical phase error (0.02 radians).
Chen, Qingyan "Yan"
BUILDING ENERGY AND CFD SIMULATION Zhiqiang Zhai* Department of Civil, Environmental and Architectural, IN 47907-2088, USA ABSTRACT The integration of building Energy Simulation (ES) and Computational Fluid, Energy Simulation, CFD, Coupling INTRODUCTION A building energy simulation (ES) program predicts building
Oldenburg, C.M.
2013-01-01T23:59:59.000Z
for estimates of the oil and gas flow rate from the Macondoteam and carried out oil and gas flow simulations using theoil-gas system. The flow of oil and gas was simulated using
Gu, Heng
2010-01-14T23:59:59.000Z
A NUMERICAL SIMULATION OF THERMAL AND ELECTRICAL PROPERTIES OF NANO-FIBER NETWORK POLYMER COMPOSITES USING PERCOLATION THEORY AND MONTE CARLO METHOD A Thesis by HENG GU Submitted to the Office of Graduate Studies of Texas A... COMPOSITES USING PERCOLATION THEORY AND MONTE CARLO METHOD A Thesis by HENG GU Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by...
Chen, Jacqueline H.; Hawkes, Evatt R.
2004-08-01T23:59:59.000Z
Direct numerical simulation (DNS) with complex chemistry was used to study statistics of displacement and consumption speeds in turbulent lean premixed methane-air flames. The main focus of the study is an evaluation of the extent to which a turbulent flame in the thin reaction zones regime can be described by an ensemble of strained laminar flames. Conditional averages with respect to strain for displacement and consumption speeds are presented over a wide range of strain typically encountered in a turbulent flame, compared with previous studies that either made local pointwise comparisons or conditioned the data on small strain and curvature. The conditional averages for positive strains are compared with calculated data from two different canonical strained laminar configurations to determine which is the optimal representation of a laminar flame structure embedded in a turbulent flame: the reactant-to-product (R-to-P) configuration or the symmetric twin flame configuration. Displacement speed statistics are compared for the progress-variable isosurface of maximum reaction rate and an isosurface toward the fresh gases, which are relevant for both modeling and interpretation of experiment results. Displacement speeds in the inner reaction layer are found to agree very well with the laminar R-to-P calculations over a wide range of strain for higher Damkhler number conditions, well beyond the regime in which agreement was expected. For lower Damkhler numbers, a reduced response to strain is observed, consistent with previous studies and theoretical expectations. Compared with the inner layer, broader and shifted probability density functions (PDFs) of displacement speed were observed in the fresh gases, and the agreement with the R-to-P calculations deteriorated. Consumption speeds show a poorer agreement with strained laminar calculations, which is attributed to multidimensional effects and a more attenuated unsteady response to strain fluctuations; however, they also show less departure from the unstrained laminar value, suggesting that detailed modeling of this quantity may not be critical for the conditions considered. For all quantities investigated, including CO production, the R-to-P laminar configuration provides an improved description relative to the twin flame configuration, which predicts qualitatively incorrect trends and overestimates extinction.
Kelley, N.D.; Wright, A.D.; Buhl, M.L. Jr.; Tangler, J.L.
1996-10-01T23:59:59.000Z
Notable progress was made in simulating the dynamic response of operating wind turbines during the past several years. In concert with these activities, the ability to adequately simulate the characteristics of the turbulent inflow, which is directly or indirectly responsible for much of the observed response, has also improved significantly. Recent investigations have shown that without such inflow simulations, it is often difficult to predict fatigue-load distributions that agree with observations. In this paper we discuss the results of a numerical experiment in which we simulated representative diurnal variations in the inflow environments for two distinct locations within a multi-row wind farm: upwind of the first and downwind of the last row of turbines. With the SNLWIND-3D turbulence simulation code, we created a series of 144, 10-minute inflow records that are likely to occur individually within a 24-hour period at each location. An upwind, rigid-hub, three-bladed turbine was modeled with the Yaw Dynamics (YawDyn) and Automatic Dynamic Analysis of Mechanical Systems (ADAMS) simulation codes while a downwind, teetered-hub, two-bladed turbine was simulated with the Fatigue, Aerodynamics, Structures, and Turbulence (FAST) code and ADAMS. We found good to excellent agreement between the codes themselves in predicting the flapwise bending load spectra, and with limited test data.
Mueschke, N; Schilling, O
2008-07-23T23:59:59.000Z
A 1152 x 760 x 1280 direct numerical simulation (DNS) using initial conditions, geometry, and physical parameters chosen to approximate those of a transitional, small Atwood number Rayleigh-Taylor mixing experiment [Mueschke, Andrews and Schilling, J. Fluid Mech. 567, 27 (2006)] is presented. The density and velocity fluctuations measured just off of the splitter plate in this buoyantly unstable water channel experiment were parameterized to provide physically-realistic, anisotropic initial conditions for the DNS. The methodology for parameterizing the measured data and numerically implementing the resulting perturbation spectra in the simulation is discussed in detail. The DNS model of the experiment is then validated by comparing quantities from the simulation to experimental measurements. In particular, large-scale quantities (such as the bubble front penetration hb and the mixing layer growth parameter {alpha}{sub b}), higher-order statistics (such as velocity variances and the molecular mixing parameter {theta}), and vertical velocity and density variance spectra from the DNS are shown to be in favorable agreement with the experimental data. Differences between the quantities obtained from the DNS and from experimental measurements are related to limitations in the dynamic range of scales resolved in the simulation and other idealizations of the simulation model. This work demonstrates that a parameterization of experimentally-measured initial conditions can yield simulation data that quantitatively agrees well with experimentally-measured low- and higher-order statistics in a Rayleigh-Taylor mixing layer. This study also provides resolution and initial conditions implementation requirements needed to simulate a physical Rayleigh-Taylor mixing experiment. In Part II [Mueschke and Schilling, Phys. Fluids (2008)], other quantities not measured in the experiment are obtained from the DNS and discussed, such as the integral- and Taylor-scale Reynolds numbers, Reynolds stress anisotropy and two-dimensional density and velocity variance spectra, hypothetical chemical product formation measures, other local and global mixing parameters, and the statistical composition of mixed fluid.
Salpeter, Nathaniel
2012-07-16T23:59:59.000Z
for design engineers. To validate this method, synthetic verification data, experimental data sets, and numerical results are used. The first experimental work involves flow through the side entry orifice (SEO) of a boiling water reactor (BWR) using non...
Boppa, Praneetha
2012-10-19T23:59:59.000Z
components. The effects of cavitation included in previous studies were not effective. The effect of different design parameters were not studied thoroughly as experimental investigation of squeeze film dampers is very expensive. Few of them used numerical...
Daniel A. Hemberger; Geoffrey Lovelace; Thomas J. Loredo; Lawrence E. Kidder; Mark A. Scheel; Béla Szilágyi; Nicholas W. Taylor; Saul A. Teukolsky
2013-09-23T23:59:59.000Z
The behavior of merging black holes (including the emitted gravitational waves and the properties of the remnant) can currently be computed only by numerical simulations. This paper introduces ten numerical relativity simulations of binary black holes with equal masses and equal spins aligned or anti-aligned with the orbital angular momentum. The initial spin magnitudes have $|\\chi_i| \\lesssim 0.95$ and are more concentrated in the aligned direction because of the greater astrophysical interest of this case. We combine this data with five previously reported simulations of the same configuration, but with different spin magnitudes, including the highest spin simulated to date, $\\chi_i \\approx 0.97$. This data set is sufficiently accurate to enable us to offer improved analytic fitting formulae for the final spin and for the energy radiated by gravitational waves as a function of initial spin. The improved fitting formulae can help to improve our understanding of the properties of binary black hole merger remnants and can be used to enhance future approximate waveforms for gravitational wave searches, such as Effective-One-Body waveforms.
Wu, Yu-Shu
2000-01-01T23:59:59.000Z
flow simulations in fractured reservoirs, Report LBL-15227,behavior of naturally fractured reservoirs, Soc. Pet. Eng.Flow in Porous and Fractured Reservoirs Yu-Shu Wu Earth
Gedney, S.D.
1987-09-01T23:59:59.000Z
The electromagnetic pulse (EMP) produced by a high-altitude nuclear blast presents a severe threat to electronic systems due to its extreme characteristics. To test the vulnerability of large systems, such as airplanes, missiles, or satellites, they must be subjected to a simulated EMP environment. One type of simulator that has been used to approximate the EMP environment is the Large Parallel-Plate Bounded-Wave Simulator. It is a guided-wave simulator which has properties of a transmission line and supports a single TEM model at sufficiently low frequencies. This type of simulator consists of finite-width parallel-plate waveguides, which are excited by a wave launcher and terminated by a wave receptor. This study addresses the field distribution within a finite-width parallel-plate waveguide that is matched to a conical tapered waveguide at either end. Characteristics of a parallel-plate bounded-wave EMP simulator were developed using scattering theory, thin-wire mesh approximation of the conducting surfaces, and the Numerical Electronics Code (NEC). Background is provided for readers to use the NEC as a tool in solving thin-wire scattering problems.
Towards Real Earth Models --Computational Geophysics on Unstructured Tetrahedral Meshes?
Farquharson, Colin G.
Towards Real Earth Models -- Computational Geophysics on Unstructured Tetrahedral Meshes? Colin tetrahedral meshes. EM geophysics on unstructured tetrahedral meshes. Disadvantages, difficulties, challenges. Conclusions. #12;Outline: Geological models! Advantages of unstructured tetrahedral meshes. EM geophysics
Skibinski, Jakub; Wejrzanowski, Tomasz [Warsaw University of Technology, Faculty of Materials Science and Engineering, Woloska 141, 02507 Warsaw (Poland); Caban, Piotr [Institute of Electronic Materials Technology, Wolczynska 133, 01919 Warsaw (Poland); Kurzydlowski, Krzysztof J. [Warsaw University of Technology, Faculty of Materials Science and Engineering Woloska, 141, 02507 Warsaw (Poland)
2014-10-06T23:59:59.000Z
In the present study numerical simulations of epitaxial growth of gallium nitride in Metal Organic Vapor Phase Epitaxy reactor AIX-200/4RF-S is addressed. Epitaxial growth means crystal growth that progresses while inheriting the laminar structure and the orientation of substrate crystals. One of the technological problems is to obtain homogeneous growth rate over the main deposit area. Since there are many agents influencing reaction on crystal area such as temperature, pressure, gas flow or reactor geometry, it is difficult to design optimal process. According to the fact that it's impossible to determine experimentally the exact distribution of heat and mass transfer inside the reactor during crystal growth, modeling is the only solution to understand the process precisely. Numerical simulations allow to understand the epitaxial process by calculation of heat and mass transfer distribution during growth of gallium nitride. Including chemical reactions in numerical model allows to calculate the growth rate of the substrate and estimate the optimal process conditions for obtaining the most homogeneous product.
Rasool, Syed Ahmed
1994-01-01T23:59:59.000Z
A vast amount of research has been conducted on the subject of pressure drop in muldphase flow systems. The simulator developed for this research incorporates the Beggs and Brill model for pressure drop prediction with an equation of state...
Archibald, Richard Andrew
2009-01-01T23:59:59.000Z
We present the results of fully three dimensional, post-Newtonian hydrodynamical simulations of the dynamical evolution of mergers between compact stellar remnants (neutron stars and black holes). Although the code is ...
Scotti, Alberto
fluctuations due to the oscillatory free stream are usually confined within a thin oscillating boundary layer3 and Oscillating Turbulent Boundary Layers Yeon S. Changa) and Alberto Scottib) Department of Marine Sciences In this report we studied numerically the movement of suspended sediments in a turbulent boundary layer over
Baudouin, Lucie
A controlled distributed parameter model for a fluid-flexible structure system: numerical consider the problem of active reduction of vibrations in a fluid-flexible structure system and the sloshing of the fuel inside the wing's tank. The control is performed using piezoelectric patches
Matteo Viel; Martin G. Haehnelt; Volker Springel
2006-04-20T23:59:59.000Z
We implement the hydro-PM (HPM) technique (Gnedin & Hui 1998) in the hydrodynamical simulation code GADGET-II and quantify the differences between this approximate method and full hydrodynamical simulations of the Lyman-alpha forest in a concordance LCDM model. At redshifts z=3 and z=4, the differences between the gas and dark matter (DM) distributions, as measured by the one-point distribution of density fluctuations, the density power spectrum and the flux power spectrum, systematically decrease with increasing resolution of the HPM simulqation. However, reducing these differences to less than a few percent requires a significantly larger number of grid-cells than particles, with a correspondingly larger demand for memory. Significant differences in the flux decrement distribution remain even for very high resolution hydro-PM simulations, particularly at low redshift. At z=2, the differences between the flux power spectra obtained from HPM simulations and full hydrodynamical simulations are generally large and of the order of 20-30 %, and do not decrease with increasing resolution of the HPM simulation. This is due to the presence of large amounts of shock-heated gas, a situation which is not adequately modelled by the HPM approximation. We confirm the results of Gnedin & Hui (1998) that the statistical properties of the flux distribution are discrepant by > 5-20 % when compared to full hydrodynamical simulations. The discrepancies in the flux power spectrum are strongly scale- and redshift-dependent and extend to large scales. Considerable caution is needed in attempts to use calibrated HPM simulations for quantitative predictions of the flux power spectrum and other statistical properties of the Lyman-alpha forest.
Takase, Kazuyuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan)
1997-05-01T23:59:59.000Z
Thermal-hydraulic characteristics in a spacer-ribbed annular fuel channel for high-temperature gas-cooled reactors were analyzed numerically by three-dimensional computations under a fully developed turbulent flow. The two-equation {kappa}-{epsilon} turbulence model was applied in the present turbulent analysis, and the turbulence model constants for eddy viscosity and the turbulent Prandtl number were improved from the previous standard values to increase the accuracy of numerical simulations. Consequently, heat transfer coefficients and friction factors in the spacer-ribbed fuel channel were predicted with sufficient accuracy in the range of Reynolds number >3,000. It was clarified quantitatively that the main mechanism for heat transfer augmentation in the spacer-ribbed fuel channel was a combined effect of the turbulence promoter effect by the spacer rib and the velocity acceleration effect by a reduction in the channel cross section.
Vijaykumar, Anand
2011-02-22T23:59:59.000Z
.05mm and clearance= 1.27mm (50 mil). The rotor is maintained initially at an eccentricity of 50% (25mil). The 3D modeling is based on the actual seal geometry used in the experiments. The entire geometry is meshed using a hexahedral grid which.... Numerical Simulation Model Five Test Cases Were Run 1. 50Mil clearance, 25Mil eccentricity, Circular orbit, 60hz case with whirl. 15 2. 50Mil clearance, 25Mil eccentricity, Circular orbit 60hz, Coordinate transformation. 3. 50Mil clearance, 25...
Nikoleris, Teo
1988-01-01T23:59:59.000Z
Fluid in a Rectangular Channel (December 1988) Teo Nikoleris, B. S. , Reed College Chairman of Advisory Committee: Dr. R. Darby An orthogonal collocation finite element program was used to numerically model the hydrodynamicslly and thermally... in negligible increase of Nw~ ~?. Also, the approach of Chang and Finlayson [6], [7] who applied orthogonal collocation finite elements in conjunction with bicubic Hermitian polynomials to approximate various viscoelastic flow problems, also met with little...
Hanson, David Edward [Los Alamos National Laboratory
2009-01-01T23:59:59.000Z
We report the results of numerical simulations of random, three-dimensional, periodic, tetrafunctional networks in response to a volume-preserving tensile strain. For the intranode force, we use a polynomial fit to a purely enthalpic ab initio force extension curve for extended polyisoprene. The simulation includes a relaxation procedure to minimize the node forces and enforces chain rupture when the extension of a network chain reaches the ab initio rupture strain. For the reasonable assumption that the distribution of network chain lengths is Gaussian, we find that the calculated snap-back velocity, temperature increase due to chain ruptures and predicted tensile stress versus strain curve are consistent with experimental data in the moderate to high extension regime. Our results show that a perfect tetrafunctional polyisoprene network is extremely robust, capable of supporting tensile stresses at least a factor of 10 greater than what is observed experimentally.
Koldanov, V. A.; Korobkov, S. V.; Gushchin, M. E.; Kostrov, A. V. [Russian Academy of Sciences, Institute of Applied Physics (Russian Federation)
2011-08-15T23:59:59.000Z
The electromagnetic fields excited by circular loop antennas in a magnetized plasma in the whistler frequency range are simulated by the finite-difference time-domain method. The spatial structure of quasi-monochromatic fields excited in the near- and far-field zones by an antenna with a harmonic current, as well as the dynamics of the electromagnetic field excited by an antenna with a current in the form of a single video pulse, is studied. Simulations performed for a uniform plasma and uniform ambient magnetic field agree well with the results of theoretical analysis and model laboratory experiments performed on large-scale plasma devices.
Mahesh, Krishnan
simulation of turbulent jets in crossflow Suman Muppidi and Krishnan Mahesh University of Minnesota crossflow. The velocity ratio of the jet to that of the crossflow is 5.7 and the Reynolds number based agreement. I. Introduction A jet in crossflow is defined as the flow field where a jet of fluid enters
Numerical Simulations of Violent Free Surface by a Coupled Level-Set and Volume-of-Fluid Method
Zhao, Yucheng
2014-04-18T23:59:59.000Z
stream_source_info ZHAO-DISSERTATION-2014.pdf.txt stream_content_type text/plain stream_size 144601 Content-Encoding UTF-8 stream_name ZHAO-DISSERTATION-2014.pdf.txt Content-Type text/plain; charset=UTF-8 NUMERICAL... for the degree of DOCTOR OF PHILOSOPHY Chair of Committee, Hamn-Ching Chen Committee Members, Jun Zhang Robert Handler Scott A. Socolofsky Head of Department, Robin Autenrieth May 2014 Major Subject: Ocean Engineering Copyright 2014 Yucheng...
C. S. S. Brandao; J. C. N. de Araujo
2012-04-24T23:59:59.000Z
A way to probe alternative theories of gravitation is to study if they could account for the structures of the universe. We then modified the well-known Gadget-2 code to probe alternative theories of gravitation through galactic dynamics. As an application, we simulate the evolution of spiral galaxies to probe alternative theories of gravitation whose weak field limits have a Yukawa-like gravitational potential. These simulations show that galactic dynamics can be used to constrain the parameters associated with alternative theories of gravitation. It is worth stressing that the recipe given in the present study can be applied to any other alternative theory of gravitation in which the superposition principle is valid.
Brandao, C. S. S.; De Araujo, J. C. N., E-mail: claudiosoriano.uesc@gmail.com, E-mail: jcarlos.dearaujo@inpe.br [Divisao de Astrofisica, Instituto Nacional de Pesquisas Espaciais, S. J. Campos, SP 12227-010 (Brazil)
2012-05-01T23:59:59.000Z
A way to probe alternative theories of gravitation is to study if they could account for the structures of the universe. We therefore modified the well-known Gadget-2 code to probe alternative theories of gravitation through galactic dynamics. As an application, we simulate the evolution of spiral galaxies to probe alternative theories of gravitation whose weak field limits have a Yukawa-like gravitational potential. These simulations show that galactic dynamics can be used to constrain the parameters associated with alternative theories of gravitation. It is worth stressing that the recipe given in this study can be applied to any other alternative theory of gravitation in which the superposition principle is valid.
Gupta, A.; Moridis, G.J.; Kneafsey, T.J.; Sloan, Jr., E.D.
2009-08-15T23:59:59.000Z
The numerical simulator TOUGH+HYDRATE (T+H) was used to predict the transient pure methane hydrate (no sediment) dissociation data. X-ray computed tomography (CT) was used to visualize the methane hydrate formation and dissociation processes. A methane hydrate sample was formed from granular ice in a cylindrical vessel, and slow depressurization combined with thermal stimulation was applied to dissociate the hydrate sample. CT images showed that the water produced from the hydrate dissociation accumulated at the bottom of the vessel and increased the hydrate dissociation rate there. CT images were obtained during hydrate dissociation to confirm the radial dissociation of the hydrate sample. This radial dissociation process has implications for dissociation of hydrates in pipelines, suggesting lower dissociation times than for longitudinal dissociation. These observations were also confirmed by the numerical simulator predictions, which were in good agreement with the measured thermal data during hydrate dissociation. System pressure and sample temperature measured at the sample center followed the CH{sub 4} hydrate L{sub w}+H+V equilibrium line during hydrate dissociation. The predicted cumulative methane gas production was within 5% of the measured data. Thus, this study validated our simulation approach and assumptions, which include stationary pure methane hydrate-skeleton, equilibrium hydrate-dissociation and heat- and mass-transfer in predicting hydrate dissociation in the absence of sediments. It should be noted that the application of T+H for the pure methane hydrate system (no sediment) is outside the general applicability limits of T+H.
Previtali, V.; Stancari, G.; Valishev, A.; /Fermilab; Shatilov, D.N.; /Novosibirsk, IYF
2012-05-01T23:59:59.000Z
Transverse beam diffusion for the Tevatron machine has been calculated using the Lifetrac code. The following effects were included: random noise (representing residual gas scattering, voltage noise in the accelerating cavities) lattice nonlinearities and beam-beam interactions. The time evolution of particle distributions with different initial amplitudes in Hamiltonian action has been simulated for 6 million turns, corresponding to a time of about 2 minutes. For each particle distribution, several cases have been considered: a single beam in storage ring mode, the collider case and the effects of a hollow electron beam collimator. The diffusion coefficient for some representative points in the amplitude space has been calculated by fitting the time evolution of delta-like particle distributions using the diffusion equation, for different machine conditions. The results confirm a strong efficiency of the electron lens as an halo diffusive enhancer, leading to diffusion coefficients which are at least a factor 10K higher than the values obtained for the collision case. This result is confirmed by the Frequency Map Analysis, which shows a clear intensification of resonance lines for particle amplitudes larger than the electron lens inner radius. If compared with past experiments, the simulations successfully reproduce the diffusion coefficients for the beam core, but still present a large discrepancy for halo particles, still under investigation.
Spiga, D; Pareschi, G
2015-01-01T23:59:59.000Z
Future X-ray telescopes like SIMBOL-X will operate in a wide band of the X-ray spectrum (from 0.1 to 80 keV); these telescopes will extend the optical performances of the existing soft X-ray telescopes to the hard X-ray band, and in particular they will be characterized by a angular resolution (conveniently expressed in terms of HEW, Half-Energy- Width) less than 20 arcsec. However, it is well known that the microroughness of the reflecting surfaces of the optics causes the scattering of X-rays. As a consequence, the imaging quality can be severely degraded. Moreover, the X-ray scattering can be the dominant problem in hard X-rays because its relevance is an increasing function of the photon energy. In this work we consistently apply a numerical method and an analytical one to evaluate the X-ray scattering impact on the HEW of an X-ray optic, as a function of the photon energy: both methods can also include the effects of figure errors in determining the final HEW. A comparison of the results obtained with th...
Ali, Melkamu; Ye, Sheng; Li, Hongyi; Huang, Maoyi; Leung, Lai-Yung R.; Fiori, Aldo; Sivapalan, Murugesu
2014-07-19T23:59:59.000Z
Subsurface stormflow is an important component of the rainfall-runoff response, especially in steep forested regions. However; its contribution is poorly represented in current generation of land surface hydrological models (LSMs) and catchment-scale rainfall-runoff models. The lack of physical basis of common parameterizations precludes a priori estimation (i.e. without calibration), which is a major drawback for prediction in ungauged basins, or for use in global models. This paper is aimed at deriving physically based parameterizations of the storage-discharge relationship relating to subsurface flow. These parameterizations are derived through a two-step up-scaling procedure: firstly, through simulations with a physically based (Darcian) subsurface flow model for idealized three dimensional rectangular hillslopes, accounting for within-hillslope random heterogeneity of soil hydraulic properties, and secondly, through subsequent up-scaling to the catchment scale by accounting for between-hillslope and within-catchment heterogeneity of topographic features (e.g., slope). These theoretical simulation results produced parameterizations of the storage-discharge relationship in terms of soil hydraulic properties, topographic slope and their heterogeneities, which were consistent with results of previous studies. Yet, regionalization of the resulting storage-discharge relations across 50 actual catchments in eastern United States, and a comparison of the regionalized results with equivalent empirical results obtained on the basis of analysis of observed streamflow recession curves, revealed a systematic inconsistency. It was found that the difference between the theoretical and empirically derived results could be explained, to first order, by climate in the form of climatic aridity index. This suggests a possible codependence of climate, soils, vegetation and topographic properties, and suggests that subsurface flow parameterization needed for ungauged locations must account for both the physics of flow in heterogeneous landscapes, and the co-dependence of soil and topographic properties with climate, including possibly the mediating role of vegetation.
Oudini, N. [Laboratoire des plasmas de décharges, Centre de Développement des Technologies Avancées, Cité du 20 Aout BP 17 Baba Hassen, 16081 Algiers (Algeria); Taccogna, F. [Istituto di Metodologie Inorganiche e dei Plasmi, CNR, via Amendola 122/D, 70126 Bari (Italy); Bendib, A. [Laboratoire d'Electronique Quantique, Faculté de Physique, USTHB, El Alia BP 32, Bab Ezzouar 16111, Algiers (Algeria); Aanesland, A. [Laboratoire de Physique des Plasmas (CNRS, Ecole Polytechnique, Sorbonne Universités, UPMC Univ Paris 06, Univ Paris-Sud), École Polytechnique, 91128 Palaiseau Cedex (France)
2014-06-15T23:59:59.000Z
Laser photo-detachment is used as a method to measure or determine the negative ion density and temperature in electronegative plasmas. In essence, the method consists of producing an electropositive channel (negative ion free region) via pulsed laser photo-detachment within an electronegative plasma bulk. Electrostatic probes placed in this channel measure the change in the electron density. A second pulse might be used to track the negative ion recovery. From this, the negative ion density and temperature can be determined. We study the formation and relaxation of the electropositive channel via a two-dimensional Particle-In-Cell/Mote Carlo collision model. The simulation is mainly carried out in a Hydrogen plasma with an electronegativity of ??=?1, with a parametric study for ? up to 20. The temporal and spatial evolution of the plasma potential and the electron densities shows the formation of a double layer (DL) confining the photo-detached electrons within the electropositive channel. This DL evolves into two fronts that move in the opposite directions inside and outside of the laser spot region. As a consequence, within the laser spot region, the background and photo-detached electron energy distribution function relaxes/thermalizes via collisionless effects such as Fermi acceleration and Landau damping. Moreover, the simulations show that collisional effects and the DL electric field strength might play a non-negligible role in the negative ion recovery within the laser spot region, leading to a two-temperature negative ion distribution. The latter result might have important effects in the determination of the negative ion density and temperature from laser photo detachment diagnostic.
Gokaltun, Seckin [Florida International Univ., Miami, FL (United States); Munroe, Norman [Florida International Univ., Miami, FL (United States); Subramaniam, Shankar [Iowa State Univ., Ames, IA (United States)
2014-12-31T23:59:59.000Z
This study presents a new drag model, based on the cohesive inter-particle forces, implemented in the MFIX code. This new drag model combines an existing standard model in MFIX with a particle-based drag model based on a switching principle. Switches between the models in the computational domain occur where strong particle-to-particle cohesion potential is detected. Three versions of the new model were obtained by using one standard drag model in each version. Later, performance of each version was compared against available experimental data for a fluidized bed, published in the literature and used extensively by other researchers for validation purposes. In our analysis of the results, we first observed that standard models used in this research were incapable of producing closely matching results. Then, we showed for a simple case that a threshold is needed to be set on the solid volume fraction. This modification was applied to avoid non-physical results for the clustering predictions, when governing equation of the solid granular temperate was solved. Later, we used our hybrid technique and observed the capability of our approach in improving the numerical results significantly; however, improvement of the results depended on the threshold of the cohesive index, which was used in the switching procedure. Our results showed that small values of the threshold for the cohesive index could result in significant reduction of the computational error for all the versions of the proposed drag model. In addition, we redesigned an existing circulating fluidized bed (CFB) test facility in order to create validation cases for clustering regime of Geldart A type particles.
Developments in Petroleum Science, 6 FUNDAMENTALS OF NUMERICAL
Santos, Juan
Developments in Petroleum Science, 6 FUNDAMENTALS OF NUMERICAL RESERVOIR SIMULATION DONALD WCongressCatalogingin PublicationData Peaceman, Donald W Fundamentals of numerical reservoir simulation. (develrpents in petroleum
The Burn-UD code for the numerical simulations of the Hadronic-to-Quark-Matter phase transition
Ouyed, Amir; Koning, Nico; Ouyed, Rachid
2015-01-01T23:59:59.000Z
Burn-UD is a hydrodynamic combustion code used to model the phase transition of hadronic to quark matter with particular application to the interior of neutron stars. Burn-UD models the flame micro-physics for different equations of state (EoS) on both sides of the interface, i.e. for both the ash (up-down-strange quark phase) and the fuel (up-down quark phase). It also allows the user to explore strange quark seeding produced by different processes including DM annihilation inside neutron stars. The simulations provide a physical window to diagnose whether the combustion process will simmer quietly and slowly, lead to a transition from deflagration to detonation or a (quark) core-collapse explosion. Such an energetic phase transition (a Quark-Nova) would have consequences in high-energy astrophysics and could aid in our understanding of many still enigmatic astrophysical transients. Furthermore, having a precise understanding of the phase transition dynamics for different EoSs could aid further in constraini...
Ewing, Richard E.
and Information Volume 1, Number 1, Pages 116 HIGH PERFORMANCE COMPUTING IN PETROLEUM APPLICATIONS RICHARD E in petroleum applications is to try to optimize the recovery of hydrocarbon from permeable underground the complex geomechanical, physical, and multiphase fluid flow processes that accompany the various recov- ery
Scott W. Randall; Maxim Markevitch; Douglas Clowe; Anthony H. Gonzalez; Marusa Bradac
2007-04-02T23:59:59.000Z
(Abridged) We compare recent results from X-ray, strong lensing, weak lensing, and optical observations with numerical simulations of the merging galaxy cluster 1E0657-56. X-ray observations reveal a bullet-like subcluster with a prominent bow shock, while lensing results show that the positions of the total mass peaks are consistent with the centroids of the collisionless galaxies (and inconsistent with the X-ray brightness peaks). Previous studies, based on older observational datasets, have placed upper limits on the self-interaction cross-section of dark matter per unit mass, sigma/m, using simplified analytic techniques. In this work, we take advantage of new, higher-quality observational datasets by running N-body simulations of 1E0657-56 that include the effects of self-interacting dark matter, and comparing the results with observations. Furthermore, the recent data allow for a new independent method of constraining sigma/m, based on the non-observation of an offset between the bullet subcluster mass peak and galaxy centroid. This new method places an upper limit (68% confidence) of sigma/m cold dark matter model and observations.
Myshakin, Evgeniy M.; Gaddipati, Manohar; Rose, Kelly; Anderson, Brian J.
2012-06-01T23:59:59.000Z
In 2009, the Gulf of Mexico (GOM) Gas Hydrates Joint-Industry-Project (JIP) Leg II drilling program confirmed that gas hydrate occurs at high saturations within reservoir-quality sands in the GOM. A comprehensive logging-while-drilling dataset was collected from seven wells at three sites, including two wells at the Walker Ridge 313 site. By constraining the saturations and thicknesses of hydrate-bearing sands using logging-while-drilling data, two-dimensional (2D), cylindrical, r-z and three-dimensional (3D) reservoir models were simulated. The gas hydrate occurrences inferred from seismic analysis are used to delineate the areal extent of the 3D reservoir models. Numerical simulations of gas production from the Walker Ridge reservoirs were conducted using the depressurization method at a constant bottomhole pressure. Results of these simulations indicate that these hydrate deposits are readily produced, owing to high intrinsic reservoir-quality and their proximity to the base of hydrate stability. The elevated in situ reservoir temperatures contribute to high (5–40 MMscf/day) predicted production rates. The production rates obtained from the 2D and 3D models are in close agreement. To evaluate the effect of spatial dimensions, the 2D reservoir domains were simulated at two outer radii. The results showed increased potential for formation of secondary hydrate and appearance of lag time for production rates as reservoir size increases. Similar phenomena were observed in the 3D reservoir models. The results also suggest that interbedded gas hydrate accumulations might be preferable targets for gas production in comparison with massive deposits. Hydrate in such accumulations can be readily dissociated due to heat supply from surrounding hydrate-free zones. Special cases were considered to evaluate the effect of overburden and underburden permeability on production. The obtained data show that production can be significantly degraded in comparison with a case using impermeable boundaries. The main reason for the reduced productivity is water influx from the surrounding strata; a secondary cause is gas escape into the overburden. The results dictate that in order to reliably estimate production potential, permeability of the surroundings has to be included in a model.
Eindhoven, Technische Universiteit
Numerical Simulation of PulseTube Refrigerators: 1D model I.A. Lyulina 1 , R.M.M. Mattheij 1 , A of a pulsetube refrigerator. Conservation equations describing compressible gas flow in the tube are solved, calculate the average enthalpy flow and estimate the refrigeration power. Keywords: pulsetube refrigerator
NUMERICAL SIMULATION OF VORTEX BREAKDOWN
Prete, Vincenza Del
2011-01-01T23:59:59.000Z
axis of the tube and is called the vortex core. The basicthe tube plus a perturbation caused by the vortex breakdown.of the tube. Thus the occurrence of the vortex breakdown
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Reagan, Matthew T.; Moridis, George J.; Keen, Noel D.; Johnson, Jeffrey N.
2015-04-18T23:59:59.000Z
Hydrocarbon production from unconventional resources and the use of reservoir stimulation techniques, such as hydraulic fracturing, has grown explosively over the last decade. However, concerns have arisen that reservoir stimulation creates significant environmental threats through the creation of permeable pathways connecting the stimulated reservoir with shallower freshwater aquifers, thus resulting in the contamination of potable groundwater by escaping hydrocarbons or other reservoir fluids. This study investigates, by numerical simulation, gas and water transport between a shallow tight-gas reservoir and a shallower overlying freshwater aquifer following hydraulic fracturing operations, if such a connecting pathway has been created. We focus on twomore »general failure scenarios: (1) communication between the reservoir and aquifer via a connecting fracture or fault and (2) communication via a deteriorated, preexisting nearby well. We conclude that the key factors driving short-term transport of gas include high permeability for the connecting pathway and the overall volume of the connecting feature. Production from the reservoir is likely to mitigate release through reduction of available free gas and lowering of reservoir pressure, and not producing may increase the potential for release. We also find that hydrostatic tight-gas reservoirs are unlikely to act as a continuing source of migrating gas, as gas contained within the newly formed hydraulic fracture is the primary source for potential contamination. Such incidents of gas escape are likely to be limited in duration and scope for hydrostatic reservoirs. Reliable field and laboratory data must be acquired to constrain the factors and determine the likelihood of these outcomes.« less
Petroski, Thomas John
2000-01-01T23:59:59.000Z
observing stations, are a particular challenge for numerical models. A meteorological overview of this event is presented along with a comparison to the Maddox et al. (1979) heavy rain conceptual model. This event was fairly consistent with the conceptual...
Building ventilation: A pressure airflow model computer generation and elements of validation
Boyer, H; Adelard, L; Mara, T A
2012-01-01T23:59:59.000Z
The calculation of airflows is of great importance for detailed building thermal simulation computer codes, these airflows most frequently constituting an important thermal coupling between the building and the outside on one hand, and the different thermal zones on the other. The driving effects of air movement, which are the wind and the thermal buoyancy, are briefly outlined and we look closely at their coupling in the case of buildings, by exploring the difficulties associated with large openings. Some numerical problems tied to the resolving of the non-linear system established are also covered. Part of a detailled simulation software (CODYRUN), the numerical implementation of this airflow model is explained, insisting on data organization and processing allowing the calculation of the airflows. Comparisons are then made between the model results and in one hand analytical expressions and in another and experimental measurements in case of a collective dwelling.
Petroski, Thomas John
2000-01-01T23:59:59.000Z
. . . . 48 . . 49 . . . . . 53 . . 60 . . 60 . . 63 CHAPTER Page V LIFTING MECHANISM. . 66 1. Introduction. 2. FAKE-DRY simulation data . 3. Model-generated vertical motion fields 4. Subjective evaluation of vertical motion. a. 500 mb positive...
An Integrated Experimental and Numerical Study: Developing a...
and natural geothermal systems. The simulator can also be used to evaluate long-term CO2 sequestration potentials. State Minnesota Objectives Modify a numerical simulator (TOUGH2)...
Ng, Chung-Sang
8/26/10 10:33 AMAPS -52nd Annual Meeting of the APS Division of Plasma Physics - Eve...er Numerical/131043 Bulletin of the American Physical Society 52nd Annual Meeting of the APS Division of Plasma Physics - Eve...er Numerical Simulations of Coronal Heating: Reduced MHD via GPGPUs Page 2 of 2http://meetings.aps
Modeling-Computer Simulations At Coso Geothermal Area (1980) | Open Energy
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Modeling-Computer Simulations At Coso Geothermal Area (2000) | Open Energy
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Modeling-Computer Simulations At Cove Fort Area (Toksoz, Et Al, 2010) |
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Modeling-Computer Simulations At Desert Peak Area (Wisian & Blackwell,
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Modeling-Computer Simulations At Geysers Area (Goff & Decker, 1983) | Open
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Modeling-Computer Simulations At Raft River Geothermal Area (1977) | Open
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a gHigh Plains WindInformation Mississippi's 3rdMitsubishi Acciona(Tempel, Et Al., 2011) |
Modeling-Computer Simulations At Raft River Geothermal Area (1979) | Open
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a gHigh Plains WindInformation Mississippi's 3rdMitsubishi Acciona(Tempel, Et Al., 2011) |Energy
Modeling-Computer Simulations At Raft River Geothermal Area (1980) | Open
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a gHigh Plains WindInformation Mississippi's 3rdMitsubishi Acciona(Tempel, Et Al., 2011)
Modeling-Computer Simulations At San Juan Volcanic Field Area (Clarkson &
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaP a gHigh Plains WindInformation Mississippi's 3rdMitsubishi Acciona(Tempel, Et Al., 2011)Reiter,
Modeling-Computer Simulations At Akutan Fumaroles Area (Kolker, Et Al.,
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:
Modeling-Computer Simulations At Central Nevada Seismic Zone Region (Biasi,
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003) | OpenEt Al.,
Modeling-Computer Simulations At Chocolate Mountains Area (Alm, Et Al.,
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003) | OpenEt Al.,2010)
Modeling-Computer Simulations At Coso Geothermal Area (1999) | Open Energy
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003) | OpenEt
Modeling-Computer Simulations At Dixie Valley Geothermal Area (Kennedy &
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003) | OpenEtEt
Modeling-Computer Simulations At Dixie Valley Geothermal Area (Wisian &
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003) | OpenEtEtEt
Modeling-Computer Simulations At Fenton Hill HDR Geothermal Area (Brown &
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003) |
Modeling-Computer Simulations At Fenton Hill HDR Geothermal Area (Goff &
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003) |Decker, 1983) |
Modeling-Computer Simulations At Fish Lake Valley Area (Deymonaz, Et Al.,
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003) |Decker, 1983)
Modeling-Computer Simulations At Hawthorne Area (Lazaro, Et Al., 2010) |
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003) |Decker, 1983)Open
Modeling-Computer Simulations At Kilauea East Rift Geothermal Area (Rudman
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003) |Decker,
Modeling-Computer Simulations At Nevada Test And Training Range Area
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003)(Farrar, Et(Sabin,
Modeling-Computer Simulations At Northern Basin & Range Region (Biasi, Et
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003)(Farrar,
Modeling-Computer Simulations At Northern Basin & Range Region (Blackwell,
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003)(Farrar,Et Al.,
Modeling-Computer Simulations At Northern Basin & Range Region (Pritchett,
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003)(Farrar,Et
Modeling-Computer Simulations At Nw Basin & Range Region (Biasi, Et Al.,
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003)(Farrar,Et2009) |
Modeling-Computer Simulations At Nw Basin & Range Region (Blackwell, Et
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003)(Farrar,Et2009)
Modeling-Computer Simulations At Nw Basin & Range Region (Laney, 2005) |
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al., 2003)(Farrar,Et2009)Open
Modeling-Computer Simulations At Nw Basin & Range Region (Pritchett, 2004)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al.,
Modeling-Computer Simulations At Obsidian Cliff Area (Hulen, Et Al., 2003)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al.,| Open Energy
Modeling-Computer Simulations At Raft River Geothermal Area (1983) | Open
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al.,| Open EnergyEnergy
Modeling-Computer Simulations At Stillwater Area (Wisian & Blackwell, 2004)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al.,| Open EnergyEnergy| Open
Modeling-Computer Simulations At The Needles Area (Bell & Ramelli, 2009) |
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al.,| Open EnergyEnergy|
Modeling-Computer Simulations At U.S. West Region (Laney, 2005) | Open
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al.,| Open
Modeling-Computer Simulations At U.S. West Region (Sabin, Et Al., 2004) |
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al.,| OpenOpen Energy
Modeling-Computer Simulations At U.S. West Region (Williams & Deangelo,
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al.,| OpenOpen Energy2008) |
Modeling-Computer Simulations At Walker-Lane Transitional Zone Region
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al.,| OpenOpenGeothermal
Modeling-Computer Simulations At Walker-Lane Transitional Zone Region
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al.,|
Modeling-Computer Simulations At Walker-Lane Transitional Zone Region
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al.,|(Pritchett, 2004) | Open
Modeling-Computer Simulations At White Mountains Area (Goff & Decker, 1983)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousPlasmaPLawrence County,1980) | Open Energy InformationGeorgia:(Blackwell, Et Al.,|(Pritchett, 2004) |
Bell, John B.
diffusion. The chemical kinetics are modeled using the DRM- 19 methane mechanism, containing 21 chemical-stabilized premixed turbulent V-flame. The computations use an adaptive projection method based on a low Mach number formulation that incorpo- rates detailed chemical kinetics and transport. The simulations are performed
Vijaykumar, Anand
2011-02-22T23:59:59.000Z
The flow field in an annular seal is simulated for synchronous circular whirl orbits with 60Hz whirl frequency and a clearance/radius ratio of 0.0154 using the Fluent Computational Fluid Dynamics (CFD) code. Fluent's Moving Reference Frame model...
Khandare, Milind Nandkumar
2012-02-14T23:59:59.000Z
combinations of rotor whirl speed, operating pressures and with and without incorporating the cavitation model. The fluid used in the simulations was ISO VG 2 Mobil Velocite no. 3. After the successful use of the cavitation model in the 2D case, a 3D model...
Garcia, C. Amanda; Halford, Keith J.; Laczniak, Randell J.
2010-02-12T23:59:59.000Z
Hydraulic conductivities of volcanic and carbonate lithologic units at the Nevada Test Site were estimated from flow logs and aquifer-test data. Borehole flow and drawdown were integrated and interpreted using a radial, axisymmetric flow model, AnalyzeHOLE. This integrated approach is used because complex well completions and heterogeneous aquifers and confining units produce vertical flow in the annular space and aquifers adjacent to the wellbore. AnalyzeHOLE simulates vertical flow, in addition to horizontal flow, which accounts for converging flow toward screen ends and diverging flow toward transmissive intervals. Simulated aquifers and confining units uniformly are subdivided by depth into intervals in which the hydraulic conductivity is estimated with the Parameter ESTimation (PEST) software. Between 50 and 150 hydraulic-conductivity parameters were estimated by minimizing weighted differences between simulated and measured flow and drawdown. Transmissivity estimates from single-well or multiple-well aquifer tests were used to constrain estimates of hydraulic conductivity. The distribution of hydraulic conductivity within each lithology had a minimum variance because estimates were constrained with Tikhonov regularization. AnalyzeHOLE simulated hydraulic-conductivity estimates for lithologic units across screened and cased intervals are as much as 100 times less than those estimated using proportional flow-log analyses applied across screened intervals only. Smaller estimates of hydraulic conductivity for individual lithologic units are simulated because sections of the unit behind cased intervals of the wellbore are not assumed to be impermeable, and therefore, can contribute flow to the wellbore. Simulated hydraulic-conductivity estimates vary by more than three orders of magnitude across a lithologic unit, indicating a high degree of heterogeneity in volcanic and carbonate-rock units. The higher water transmitting potential of carbonate-rock units relative to volcanic-rock units is exemplified by the large difference in their estimated maximum hydraulic conductivity; 4,000 and 400 feet per day, respectively. Simulated minimum estimates of hydraulic conductivity are inexact and represent the lower detection limit of the method. Minimum thicknesses of lithologic intervals also were defined for comparing AnalyzeHOLE results to hydraulic properties in regional ground-water flow models.
Grossman, A.; Errico, R.M.
1999-11-29T23:59:59.000Z
The vertical motion of constant density atmospheric balloons has been considered via an equation of motion for the vertical displacement of a balloon, due to vertical air motion, which can be numerically solved for balloon positions. Initial calculations are made for a constant density atmosphere. Various vertical wind models with relatively large amplitudes are applied to the model to determine how tightly the balloons are coupled to the reference level and the time scale for the balloons to change to the wind driven reference altitude. A surface launch of a balloon to a 6 km reference altitude is modeled using a detailed atmospheric pressure-density-temperature profile in the equation of motion. The results show the balloons to be relatively tightly coupled ({approx} 50-100 m) to the reference altitude.
Not Available
1989-11-01T23:59:59.000Z
The Department of Energy (DOE) is preparing an Environmental Impact Statement (EIS) as part of the process for continuing operation of three reactors at the Savannah River Site (SRS). As required by the National Environmental Policy Act (NEPA), the EIS must address the potential environmental consequences to human health and the environment of this major federal action.'' Some of the possible consequences are related to subsurface transport of radionuclides released to seepage basins during normal reactor operation. To assist in the evaluation of the potential subsurface environmental impacts of these releases, Camp Dresser McKee Inc. (CDM) was contracted in June of 1989 to develop a three-dimensional groundwater flow and contaminant transport model which will simulate the movement of radionuclides at each of the reactor areas after they enter the groundwater system through the seepage basins. This report describes the development, calibration, and simulation results of the groundwater flow and contaminant transport model developed for this task. 10 refs., 63 figs., 11 tabs.
Bianconi, Andrea
2014-01-01T23:59:59.000Z
Background: The epidemiology of the slightly radioactive contrast agent named Thorotrast presents a very long latency period between the injection and the development of the related pathologies. It is an example of the more general problem posed by a radioactive internal contaminant whose effects are not noteworthy in the short term but become dramatic in the long period. A point that is still to be explored is fluctuations (in space and time) in the localized absorption of radiation by the tissues. Methods: A Monte Carlo simulation code has been developed to study over a 30 year period the daily absorption of alpha radiation by micrometer sized portions of tissue placed at a distance of 0-100 micrometers from a model source, that approximates a compact thorium dioxide source in liver or spleen whose size is larger or equal to 20 micrometers. The biological depletion of the daughter nuclei of the thorium series is taken into account. The initial condition assumes chemically purified natural thorium. Results: ...
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Deiterding, Ralf
2011-01-01T23:59:59.000Z
Numerical simulation can be key to the understanding of the multidimensional nature of transient detonation waves. However, the accurate approximation of realistic detonations is demanding as a wide range of scales needs to be resolved. This paper describes a successful solution strategy that utilizes logically rectangular dynamically adaptive meshes. The hydrodynamic transport scheme and the treatment of the nonequilibrium reaction terms are sketched. A ghost fluid approach is integrated into the method to allow for embedded geometrically complex boundaries. Large-scale parallel simulations of unstable detonation structures of Chapman-Jouguet detonations in low-pressure hydrogen-oxygen-argon mixtures demonstrate the efficiency of the described techniquesmore »in practice. In particular, computations of regular cellular structures in two and three space dimensions and their development under transient conditions, that is, under diffraction and for propagation through bends are presented. Some of the observed patterns are classified by shock polar analysis, and a diagram of the transition boundaries between possible Mach reflection structures is constructed.« less
Numerical Calculation of Granular Entropy
Asenjo, Daniel; Paillusson, Fabien; Frenkel, Daan
2014-03-05T23:59:59.000Z
We present numerical simulations that allow us to compute the number of ways in which N particles can pack into a given volume V. Our technique modifies the method of Xu, Frenkel, and Liu [Phys. Rev. Lett. 106, 245502 (2011)] and outperforms...
Disruptive Innovation in Numerical Hydrodynamics
Waltz, Jacob I. [Los Alamos National Laboratory
2012-09-06T23:59:59.000Z
We propose the research and development of a high-fidelity hydrodynamic algorithm for tetrahedral meshes that will lead to a disruptive innovation in the numerical modeling of Laboratory problems. Our proposed innovation has the potential to reduce turnaround time by orders of magnitude relative to Advanced Simulation and Computing (ASC) codes; reduce simulation setup costs by millions of dollars per year; and effectively leverage Graphics Processing Unit (GPU) and future Exascale computing hardware. If successful, this work will lead to a dramatic leap forward in the Laboratory's quest for a predictive simulation capability.
Modeling Computational Security in Long-Lived Systems, Version 2 Ran Canetti1,2
International Association for Cryptologic Research (IACR)
Modeling Computational Security in Long-Lived Systems, Version 2 Ran Canetti1,2 , Ling Cheung2 Introduction Computational security in long-lived systems: Security properties of cryptographic protocols computational power. This type of security degrades progressively over the lifetime of a protocol. However, some
Modeling Computational Security in Long-Lived Systems Ran Canetti1,2
International Association for Cryptologic Research (IACR)
Modeling Computational Security in Long-Lived Systems Ran Canetti1,2 , Ling Cheung2 , Dilsun Kaynar Introduction Computational security in long-lived systems: Security properties of cryptographic protocols protocols, security relies on the assumption that adversarial entities have lim- ited computational power
Building ventilation : a pressure airflow model computer generation and elements of
Paris-Sud XI, Université de
Building ventilation : a pressure airflow model computer generation and elements of validation H when heating a residential building, approximately 30% of the energy loss is due to air renewal[1. Thus in tropical climates, natural ventilation affects essentially the inside comfort by favouring
A Unified RANS-LES Model: Computational Development, Accuracy and Cost1 Harish Gopalana
Heinz, Stefan
-Stokes (RANS) methods, applies modeling assumptions to all the scales of motion. The17 use of LES methodsA Unified RANS-LES Model: Computational Development, Accuracy and Cost1 Harish Gopalana , Stefan Heinzb, , Michael K. Stöllingera 2 aMechanical Engineering Department, University of Wyoming, 1000 E
10.34 Numerical Methods Applied to Chemical Engineering, Fall 2001
Beers, Kenneth J.
Numerical methods for solving problems arising in heat and mass transfer, fluid mechanics, chemical reaction engineering, and molecular simulation. Topics: numerical linear algebra, solution of nonlinear algebraic equations ...
Numerical simulation of sandstone reservoir models
Gross, Stephen Joseph
1983-01-01T23:59:59.000Z
0 0. 1 0. 2 Or3 0. 4 O. S 0. 6 Or7 0. 8 Or9 I GAS SATURATIOMr FRACTION OF PORE VOLUME Figure 4 ? Relative permeability of gas-oil system for Layer 1 Table 1 - Layer Properties 'v ~La er ~md ~md 1 500 250 0. 22 0. 20 0. 20 0. 05 2 200 100 0. 21... ? - 2o. 'a STB/o """ 50. 0 STB/0 r J't. , ~~'$ ' v 'i ti, 0 2 4 6 8 10 12 14 16 18 OIL RfCIMRYi 2BIP Figure 12 - Gas-oil ratio behavior of so'lution gas drive runs for Case 4, a homogeneous interval 3500 A G E 3000 2saa 2000 lsaa ? CASE 1...
A numerical sensitivity analysis of streamline simulation
Chaban Habib, Fady Ruben
2005-02-17T23:59:59.000Z
.9.................................................................................................. 88 4.60 Homogeneous with qinj=50 Bbls/D varying SegIT value.............................. 89 4.61 Homogeneous line to line with qinj=50 Bbls/D using different ? t. ............... 90 4.62 Homogeneous line to block at same PVI using ? t=20... days........................... 92 4.63 Homogeneous line to block at same PVI using ? t=5 days............................. 93 4.64 PermX distribution for heterogeneous model in gravity cases....................... 94 4.65 Heterogeneous line...
Numerical simulation of electrokinetically driven micro flows
Hahm, Jungyoon
2005-11-01T23:59:59.000Z
to control mixed electroosmotic/pressure driven flow in the grooved micro-channel. The controlled flow pattern enables entrapment and release of prescribed amounts of scalar species in the grooves. As another application, hydrodynamic/ electrokinetic focusing...
Numerical Simulations ANSYS FLUENT 14.0
partially contact end of cartridge due to machining variations, neutron-induced swelling, thermal expansion
NUMERICAL SIMULATION OF INCOMPRESSIBLE FLOWS IN ...
PDEs by boundary layer or quasi-geostrophic approximations, as well as imposing ... are to be completed with admissible initial and boundary conditions. ... eral practice, especially for spectral approximations, to treat the nonlinear terms .... spectral-Galerkin method in [19] is as good, if not more efficient and accurate, as.
Numerical Simulation of Free Standing Hybrid Risers
Hou, Tiancong
2014-08-13T23:59:59.000Z
............................................................... 11 2.2.2 Rotational Spring Boundary Condition ............................................... 12 2.2.3 Clamped Boundary Condition ............................................................. 14 2.2.4 Free Boundary Condition... difficulty. 14 2.2.3 Clamped Boundary Condition In the case of the connection between the vertical riser and upper riser assembly, a stress joint is applied. The stress joint is typically modeled as the clamped boundary condition. In other words...
A numerical sensitivity analysis of streamline simulation
Chaban Habib, Fady Ruben
2005-02-17T23:59:59.000Z
Methods........................................................18 3.2.1. Line to Block Saturation Mapping Method. ....................... 21 3.2.2. Line to Line Saturation Mapping Method. ......................... 22 3.3. Mobility... showing XYZ definitions ............................................. 12 2.2 Schematic showing the computation of exit point and travel time in 2D....... 15 3.1 Line to block saturation mapping...
Numerical Simulation of Pulse-Tube Refrigerators
Tijsseling, A.S.
. . . . . . . . . . . . . . . . . . 51 3.3.1 A model problem . . . . . . . . . . . . . . . . . 52 3.3.2 Two-grid LUGR with fixed refinement area . . . . . . . . 53 3.3.3 Two-grid LUGR with moving refinement area . . . . . . . 55 4 in fully developed pipe flow . . . . 76 5 Flow and heat transfer computations for the pulse tube 81 5.1 One
Methods for Numerical Flow Simulation Rolf Rannacher
models of laminar hemodynamical flows. We discuss space and time dis- cretization with emphasis as flow control and model calibration. We concen- trate on laminar flows in which all relevant spatial-Stokes equations The continuum mechanical model of the flow of a viscous Newtonian fluid is the system
Souza, Paulo Victor Santos
2015-01-01T23:59:59.000Z
Flow of viscous fluids are not usually discussed in detail in general and basic courses of physics. This is due in part to the fact that the Navier-Stokes equation has analytical solution only for a few restricted cases, while more sophisticated problems can only be solved by numerical methods. In this text, we present a computer simulation of wind tunnel, i.e., we present a set of programs to solve the Navier-Stokes equation for an arbitrary object inserted in a wind tunnel. The tunnel enables us to visualize the formation of vortices behind object, the so-called von K\\'arm\\'an vortices, and calculate the drag force on the object. We believe that this numerical wind tunnel can support the teacher and allow a more elaborate discussion of viscous flow. The potential of the tunnel is exemplified by the study of the drag on a simplified model of wing whose angle of attack can be controlled. A link to download the programs that make up the tunnel appears at the end.
Analysis and verification of a three-dimensional hydrodynamic numerical model
Abraham, David Daniel
1991-01-01T23:59:59.000Z
of Advisory Committee: Dr. W. P. James A three-dimensional hydrodynamic numerical model (RMA10) was analyized and verified. The verification process involved the comparison of model and measured water surface elevations, velocities, and depth averaged... velocities. The verification (measured) data were obtained from a large (200 cfs) flume. The numerical grid was set up such that the spacial location of the computational points was as close as practical to that of the measured data. The model computed...
Numerical Analysis Department Robustness improvement of
Vuik, Kees
Numerical Analysis Department Robustness improvement of polyhedral mesh method for airbag of polyhedral mesh method for airbag deployment simulations MASTER OF SCIENCE THESIS For the degree of Master entitled ROBUSTNESS IMPROVEMENT OF POLYHEDRAL MESH METHOD FOR AIRBAG DEPLOYMENT SIMULATIONS by SANTIAGO
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Reagan, Matthew T.; Moridis, George J.; Keen, Noel D.; Johnson, Jeffrey N.
2015-04-18T23:59:59.000Z
Hydrocarbon production from unconventional resources and the use of reservoir stimulation techniques, such as hydraulic fracturing, has grown explosively over the last decade. However, concerns have arisen that reservoir stimulation creates significant environmental threats through the creation of permeable pathways connecting the stimulated reservoir with shallower freshwater aquifers, thus resulting in the contamination of potable groundwater by escaping hydrocarbons or other reservoir fluids. This study investigates, by numerical simulation, gas and water transport between a shallow tight-gas reservoir and a shallower overlying freshwater aquifer following hydraulic fracturing operations, if such a connecting pathway has been created. We focus on twomore »general failure scenarios: (1) communication between the reservoir and aquifer via a connecting fracture or fault and (2) communication via a deteriorated, preexisting nearby well. We conclude that the key factors driving short-term transport of gas include high permeability for the connecting pathway and the overall volume of the connecting feature. Production from the reservoir is likely to mitigate release through reduction of available free gas and lowering of reservoir pressure, and not producing may increase the potential for release. We also find that hydrostatic tight-gas reservoirs are unlikely to act as a continuing source of migrating gas, as gas contained within the newly formed hydraulic fracture is the primary source for potential contamination. Such incidents of gas escape are likely to be limited in duration and scope for hydrostatic reservoirs. Reliable field and laboratory data must be acquired to constrain the factors and determine the likelihood of these outcomes.« less
Geometric Numerical Methods for Numerical Weather Prediction
Langdon, Stephen
-Mesh (HPM) Method · Label space is discretised into N particles with coordinates on the momentum phase space and Sij = (1 - ^2xx)-1. Geometric Numerical Methods for Numerical Weather Prediction p. 8/28 #12;HPM Equations of shallow water motions · The canonical HPM equations of 1D shallow water motion on TS1 are P
A NUMERICAL STUDY OF A FULLY CONSERVATIVE METHOD FOR HYPERELASTICVISCOPLASTIC
New York at Stoney Brook, State University of
based on a new approach to the simulation of materials undergoing large de formation. Our numericalA NUMERICAL STUDY OF A FULLY CONSERVATIVE METHOD FOR HYPERELASTICVISCOPLASTIC MATERIALS XIAO LIN algorithm for the simulation of the impact of hyperelasticviscoplastic materials in two dimensions
Kaper, Tasso J., E-mail: tasso@bu.edu; Kramer, Mark A., E-mail: mak@bu.edu [Department of Mathematics and Statistics, Boston University, Boston, Massachusetts 02215 (United States); Rotstein, Horacio G., E-mail: horacio@njit.edu [Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey 07102 (United States)
2013-12-15T23:59:59.000Z
Rhythmic neuronal oscillations across a broad range of frequencies, as well as spatiotemporal phenomena, such as waves and bumps, have been observed in various areas of the brain and proposed as critical to brain function. While there is a long and distinguished history of studying rhythms in nerve cells and neuronal networks in healthy organisms, the association and analysis of rhythms to diseases are more recent developments. Indeed, it is now thought that certain aspects of diseases of the nervous system, such as epilepsy, schizophrenia, Parkinson's, and sleep disorders, are associated with transitions or disruptions of neurological rhythms. This focus issue brings together articles presenting modeling, computational, analytical, and experimental perspectives about rhythms and dynamic transitions between them that are associated to various diseases.
142 Los Alamos Science Number 29 2005 Direct Numerical
Kurien, Susan
142 Los Alamos Science Number 29 2005 Direct Numerical Simulations of Turbulence Data Generation visualization tools. Los Alamos scientists have been able to simulate flows of Reynolds numbers up to 105 subdomain of the 20483 turbulence simulation performed on the ASC Q machine at Los Alamos. The ASC Q machine
The NumLab Numerical Laboratory J. Maubach 1 and A. Telea 2
Eindhoven, Technische Universiteit
The NumLab Numerical Laboratory J. Maubach 1 and A. Telea 2 Department of Mathematics and Computer environments addresses numerical simulation, interac- tive visualisation and computational steering. Most- bling numerical simulations from computational and visualisation blocks, as well as building such blocks
Numerical study of high heat ux pool boiling heat transfer Ying He a,*, Masahiro Shoji b
Maruyama, Shigeo
Numerical study of high heat ¯ux pool boiling heat transfer Ying He a,*, Masahiro Shoji b , Shigeo simulation model of boiling heat transfer is proposed based on a numerical macrolayer model [S. Maruyama, M. Shoji, S. Shimizu, A numerical simulation of transition boiling heat transfer, in: Proceedings
High performance computing and numerical modelling
,
2014-01-01T23:59:59.000Z
Numerical methods play an ever more important role in astrophysics. This is especially true in theoretical works, but of course, even in purely observational projects, data analysis without massive use of computational methods has become unthinkable. The key utility of computer simulations comes from their ability to solve complex systems of equations that are either intractable with analytic techniques or only amenable to highly approximative treatments. Simulations are best viewed as a powerful complement to analytic reasoning, and as the method of choice to model systems that feature enormous physical complexity such as star formation in evolving galaxies, the topic of this 43rd Saas Fee Advanced Course. The organizers asked me to lecture about high performance computing and numerical modelling in this winter school, and to specifically cover the basics of numerically treating gravity and hydrodynamics in the context of galaxy evolution. This is still a vast field, and I necessarily had to select a subset ...
2005-10-20T23:59:59.000Z
Page 1. LAB #8. Numerical Methods. Goal: The purpose of this lab is to explain how computers numerically ... Also you will examine what .... (7) Now consider the differential equation ... 3-exp(2*y)+sqrt(t)/y; (Don't forget the “;” at the end.).
International Association for Cryptologic Research (IACR)
Modeling Computational Security in LongLived Systems # ## Ran Canetti 1,2 , Ling Cheung 2 , Dilsun Introduction Computational security in longlived systems: Security properties of cryptographic protocols computational power. This type of security degrades progressively over the lifetime of a protocol. However, some
Assessment of the MUSTA approach for numerical relativistic dynamics
Blakely, P. M.; Nikiforakis, N.; Henshaw, W. D.
2015-03-04T23:59:59.000Z
waves 1. Introduction The numerical solution of the relativistic hydrodynamical equa- tions is of importance to the simulation of astrophysical phe- nomena such as gamma-ray bursts, supernova core-collapse, and relativistic wind accretion. Although...
Numerical and Experimental Investigation of Tidal Current Energy Extraction
Sun, Xiaojing
2008-01-01T23:59:59.000Z
Numerical and experimental investigations of tidal current energy extraction have been conducted in this study. A laboratory-scale water flume was simulated using commercial computational fluid dynamics (CFD) code FLUENT. ...
An investigation of the numerical treatment of condensation
Sasson, Joseph
The simulation of complete condensation continues to challenge the numerical methods currently used for multi-phase flow modeling; especially at low pressures, the change of phase process from a two-phase mixture to liquid ...
NUMERICAL ANALYSIS OF A FINITE ELEMENT SCHEME FOR THE APPROXIMATION OF HARMONIC MAPS INTO SURFACES
Bartels, Soeren
NUMERICAL ANALYSIS OF A FINITE ELEMENT SCHEME FOR THE APPROXIMATION OF HARMONIC MAPS INTO SURFACES Geometric partial differential equations and their analysis as well as numerical simulation have recently
Computation and Visualisation in the NumLab Numerical Laboratory
Telea, Alexandru C.
for the underlying mathematics. Assembling numerical simulations from computational and visualisation blocks, as wellComputation and Visualisation in the NumLab Numerical Laboratory J.M.L. Maubach1 and A.C. Telea1 Eindhoven University of Technology, Department of Mathematics and Computer Science, Postbox 513, NL-5600 MB
RIGOROUS MODELING AND SIMULATION OF MECHATRONIC SYSTEMS
Taylor, James H.
RIGOROUS MODELING AND SIMULATION OF MECHATRONIC SYSTEMS James H. Taylor Professor Emeritus, Systems on mechatronic systems. Emphasis is placed on rigorous techniques and selecting the most appropriate method mentioned above for mechatronic systems. Key Words: Mechatronic systems, modeling, simulation, numerical
Experimentally Determining Passivity Indices: Theory and Simulation
Antsaklis, Panos
's method. Simulations on a virtual car platform are given to demonstrate the results. 1 P. Wu, M.J. Mc as it is a derivative-free numerical optimization approach. Simulations of this method for a virtual car platform
Compositional changes in heavy oil steamflood simulators
Lolley, Christopher Scott
1995-01-01T23:59:59.000Z
The numerical simulation of heavy oil steamfloods has generally been conducted assuming that the oil is non-volatile. Reservoir simulation has traditionally ignored compositional effect s due to heat and steam and assumed that the hydrocarbon phase...
Numerical modeling of species transport in turbulent flow and experimental study on aerosol sampling
Vijayaraghavan, Vishnu Karthik
2007-04-25T23:59:59.000Z
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...
Numerical Investigation of turbulent coupling boundary layer of air-water interaction flow
Liu, Song, S.M. Massachusetts Institute of Technology
2005-01-01T23:59:59.000Z
Air-water interaction flow between two parallel flat plates, known as Couette flow, is simulated by direct numerical simulation. The two flowing fluids are coupled through continuity of velocity and shear stress condition ...
Hamann, Bernd
INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS Int. J. Numer. Anal geomechanics Boris Jeremi!cc1, *,y , Gerik Scheuermann2,3 , Jan Frey3 , Zhaohui Yang1 , Bernd Hamann2 , Kenneth is the visualization of stress tensors resulting from 3D numerical simulations in computational geomechanics
Introduction to exact numerical computation
Escardó, Martín
Introduction to exact numerical computation Notes 2 Floating-point computation 4 3 Exact numerical (called the operational semantics) for computing a syntactical representative of the mathematical entity
Numerical Integration Gordon K. Smyth
Smyth, Gordon K.
Numerical Integration Gordon K. Smyth in Encyclopedia of Biostatistics (ISBN 0471 975761) Edited by Peter Armitage and Theodore Colton John Wiley & Sons, Ltd, Chichester, 1998 #12;Numerical Integration Numerical integration is the study of how the numerical value of an integral can be found. Also called
Simulations Data Simulation Type
Wang, Xiaorui "Ray"
to request different simulations data. The flow chart above demonstrates the different steps and options@ornl.gov) Autotune Drupal 7 CMS Current building energy models (BEMs), using EnergyPlus or other simulations, are unreliable because they have to constantly be calibrated to match actual energy usage data. Currently
An Interactive Course in Numerical Methods for the Earth Susan E. Allen
Stockie, John
are typically in physics, mathematics, chemistry, biology or geography, and exposure to numerical computing science are becoming more and more dependent on numerical simulation, modelling, and computationally courses in numerical methods using MatlabTM as the programming language, or a graduate-level mathematics
Not Available
1992-12-01T23:59:59.000Z
The effort of the experimental group has been concentrated on the CERN ALEPH and FERMILAB D0 collider experiments and completion of two fixed target experiments. The BNL fixed target experiment 771 took the world`s largest sample of D(1285) and E/iota(1420) events, using pion, kaon and antiproton beams. Observing the following resonances: 0{sup {minus_plus}} [1280], 1{sup {plus}{plus}} [1280], 0{sup {minus_plus}} [1420], 0{sup {minus_plus}} [1470], 1{sup {plus_minus}} [1415]. The Fermilab fixed target experiment E711, dihadron production in pN interactions at 800 GeV, completed data reduction and analysis. The atomic weight dependence, when parameterized as {sigma}(A) = {sigma}{sub o}A{sup {alpha}}, yielded a value of {alpha} = 1.043 {plus_minus} 0.011 {plus_minus} .012. The cross section per nucleon and angular distributions was also measured as a function of two particle mass and agrees very well with QCD calculations. The D0 Fermilab Collider Experiment E740 began its first data taking run in April 1992. The CERN collider experiment ALEPH at LEP is presently taking more data. The Z mass and width, the couplings to the upper and lower components of the hadronic isospin doublet, forward-backward asymmetries of hadronic events, and measurements of the fragmentation process have been made. The effort of detector development for the SSC has substantially increased with particular emphasis on scintillators, both in fibers and plates. Work has continued on higher-order QCD calculations using the Monte Carlo technique developed previously. This year results for WW, ZZ, WZ, and {sub {gamma}{gamma}} production have been published. A method for incorporating parton showering in such calculations was developed and applied to W production. The multicanonical Monte Carlo algorithm has stood up to the promises anticipated; it was used in multicanonical simulations of first-order phase transitions and for spin glass systems.
11. NUMERICAL TECHNIQUES 1 Numerical identification of effective multipole
Boyer, Edmond
11. NUMERICAL TECHNIQUES 1 Numerical identification of effective multipole moments of polarizable of the induced multipole moments. A general multipole theory is available in the literature, however, only linear multipole model is usually exploited when determining numerically these effective moments. Since this axial
The phase diagram of QCD from lattice simulations Massimo D'Elia
Heller, Barbara
'Universit`a di Pisa and INFN - Sezione di Pisa, Largo Pontecorvo 3, I-56127 Pisa, Italy Numerical simulations
Numerical Integration Gordon K. Smyth
Smyth, Gordon K.
Numerical Integration Gordon K. Smyth May 1997 Numerical integration is the study of how the numerical value of an integral can be found. Also called quadrature, which refers to finding a square whose \\Lambda . Of central interest is the process of approximating a definite integral from values of the in
Lattice Boltzmann Model for Numerical Relativity
Ilseven, E
2015-01-01T23:59:59.000Z
In the Bona-Masso formulation, Einstein equations are written as a set of flux conservative first order hyperbolic equations that resemble fluid dynamics equations. Based on this formulation, we construct a lattice Boltzmann model for Numerical Relativity. Our model is validated with well-established tests, showing good agreement with analytical solutions. Furthermore, we show that by increasing the relaxation time, we gain stability at the cost of losing accuracy, and by decreasing the lattice spacings while keeping a constant numerical diffusivity, the accuracy and stability of our simulations improves. Finally, in order to show the potential of our approach a linear scaling law for parallelisation with respect to number of CPU cores is demonstrated. Our model represents the first step in using lattice kinetic theory to solve gravitational problems.
Brown, M.J.; Williams, M.D.
1997-04-01T23:59:59.000Z
Since mesoscale numerical models do not have the spatial resolution to directly simulate the fluid dynamics and thermodynamics in and around urban structures, urban canopy parameterizations are sometimes used to approximate the drag, heating, and enhanced turbulent kinetic energy (tke) produced by the sub-grid scale urban elements. In this paper, we investigate the effect of the urban canopy parameterizations used in the HOTMAC mesoscale meteorological model by turning the parameterizations on and off. The model simulations were performed in the Paso del Norte region, which includes the cities of El Paso and Ciudad Juarez, the Franklin and Sierra Juarez mountains, and the Rio Grande. The metropolitan area is surrounded by relatively barren scrubland and is intersected by strips of vegetation along the Rio Grande. Results indicate that the urban canopy parameterizations do affect the mesoscale flow field, reducing the magnitude of wind speed and changing the magnitude of the sensible heat flux and tke in the metropolitan area. A nighttime heat island and a daytime cool island exist when urban canopy parameters are turned on, but associated recirculation flows are not readily apparent. Model-computed solar, net, and longwave radiation values look reasonable, agreeing for the most part with published measurements.
Grid-independent Issue in Numerical Heat Transfer
Yao Wei; Wang Jian; Liao Guangxuan
2006-09-26T23:59:59.000Z
Grid independent is associated with the accuracy or even rationality of numerical results. This paper takes two-dimensional steady heat transfer for example to reveal the effect of grid resolution on numerical results. The law of grid dependence is obtained and a simple mathematical formula is presented. The production acquired here can be used as the guidance in choosing grid density in numerical simulation and get exact grid independent value without using infinite fine grid. Through analyzing grid independent, we can find the minimum number of grid cells that is needed to get grid-independent results. Such strategy can save computational resource while ensure a rational computational result.
Simple intrinsic defects in GaAs : numerical supplement.
Schultz, Peter Andrew
2012-04-01T23:59:59.000Z
This Report presents numerical tables summarizing properties of intrinsic defects in gallium arsenide, GaAs, as computed by density functional theory. This Report serves as a numerical supplement to the results published in: P.A. Schultz and O.A. von Lilienfeld, 'Simple intrinsic defects in GaAs', Modelling Simul. Mater. Sci Eng., Vol. 17, 084007 (2009), and intended for use as reference tables for a defect physics package in device models. The numerical results for density functional theory calculations of properties of simple intrinsic defects in gallium arsenide are presented.
Method for simulating discontinuous physical systems
Baty, Roy S. (Albuquerque, NM); Vaughn, Mark R. (Albuquerque, NM)
2001-01-01T23:59:59.000Z
The mathematical foundations of conventional numerical simulation of physical systems provide no consistent description of the behavior of such systems when subjected to discontinuous physical influences. As a result, the numerical simulation of such problems requires ad hoc encoding of specific experimental results in order to address the behavior of such discontinuous physical systems. In the present invention, these foundations are replaced by a new combination of generalized function theory and nonstandard analysis. The result is a class of new approaches to the numerical simulation of physical systems which allows the accurate and well-behaved simulation of discontinuous and other difficult physical systems, as well as simpler physical systems. Applications of this new class of numerical simulation techniques to process control, robotics, and apparatus design are outlined.
MESOSCALE SIMULATIONS OF POWDER COMPACTION
Lomov, Ilya; Fujino, Don; Antoun, Tarabay; Liu, Benjamin [Lawrence Livermore National Laboratory, P. O. Box 808, Livermore CA 94551 (United States)
2009-12-28T23:59:59.000Z
Mesoscale 3D simulations of shock compaction of metal and ceramic powders have been performed with an Eulerian hydrocode GEODYN. The approach was validated by simulating a well-characterized shock compaction experiment of a porous ductile metal. Simulation results using the Steinberg material model and handbook values for solid 2024 aluminum showed good agreement with experimental compaction curves and wave profiles. Brittle ceramic materials are not as well studied as metals, so a simple material model for solid ceramic (tungsten carbide) has been calibrated to match experimental compaction curves. Direct simulations of gas gun experiments with ceramic powders have been performed and showed good agreement with experimental data. The numerical shock wave profile has same character and thickness as that measured experimentally using VISAR. The numerical results show reshock states above the single-shock Hugoniot line as observed in experiments. We found that for good quantitative agreement with experiments 3D simulations are essential.
Numerical studies of galaxy formation using special purpose hardware
Matthias Steinmetz
2002-01-25T23:59:59.000Z
I review recent progress in numerically simulating the formation and evolution of galaxies in hierarchically clustering universes. Special emphasis is given to results based on high-resolution gas dynamical simulations using the N-body hardware integrator GRAPE. Applications address the origin of the spin of disk galaxies, the structure and kinematics of damped Lyman-alpha systems, and the origin of galaxy morphology and of galaxy scaling laws.
Tropical anvil cirrus evolution from observations and numerical simulations
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5(Million Cubic Feet) Oregon (Including Vehicle Fuel) (MillionStructural Basis of WntSupportBRAP-focused topics 1 ReviewedARM-00-005Western