Modeling-Computer Simulations At Dixie Valley Geothermal Area...
navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Dixie Valley Geothermal Area (Wisian & Blackwell, 2004) Exploration...
Modeling-Computer Simulations At Stillwater Area (Wisian & Blackwell...
navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Stillwater Area (Wisian & Blackwell, 2004) Exploration Activity...
Modeling-Computer Simulations At Valles Caldera - Redondo Geothermal...
navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Valles Caldera - Redondo Geothermal Area (Wilt & Haar, 1986)...
Modeling-Computer Simulations At Desert Peak Area (Wisian & Blackwell...
navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Desert Peak Area (Wisian & Blackwell, 2004) Exploration Activity...
Modeling-Computer Simulations At White Mountains Area (Goff ...
GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At White Mountains Area (Goff & Decker, 1983) Exploration Activity Details Location White...
Modeling-Computer Simulations At Central Nevada Seismic Zone...
Central Nevada Seismic Zone Geothermal Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not indicated DOE-funding Unknown References J. W....
Modeling-Computer Simulations At Fenton Hill HDR Geothermal Area...
Modeling-Computer Simulations At Fenton Hill HDR Geothermal Area (Goff & Decker, 1983) Exploration Activity Details Location Fenton Hill HDR Geothermal Area Exploration Technique...
Modeling-Computer Simulations At Nw Basin & Range Region (Biasi...
Location Northwest Basin and Range Geothermal Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful regional reconnaissance DOE-funding...
Modeling-Computer Simulations At Long Valley Caldera Geothermal...
navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Long Valley Caldera Geothermal Area (Battaglia, Et Al., 2003)...
Modeling-Computer Simulations At Akutan Fumaroles Area (Kolker...
navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Akutan Fumaroles Area (Kolker, Et Al., 2010) Exploration Activity...
Modeling-Computer Simulations At San Juan Volcanic Field Area...
navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At San Juan Volcanic Field Area (Clarkson & Reiter, 1987) Exploration...
Modeling-Computer Simulations At Central Nevada Seismic Zone...
Modeling-Computer Simulations At Central Nevada Seismic Zone Region (Biasi, Et Al., 2009) Exploration Activity Details Location Central Nevada Seismic Zone Geothermal Region...
Modeling-Computer Simulations At Long Valley Caldera Geothermal...
Modeling-Computer Simulations Activity Date - 2003 Usefulness not indicated DOE-funding Unknown Notes Several fluid-flow models presented regarding the Long Valley Caldera....
Modeling-Computer Simulations At Nevada Test And Training Range...
navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Nevada Test And Training Range Area (Sabin, Et Al., 2004) Exploration...
Modeling-Computer Simulations At Chocolate Mountains Area (Alm...
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Modeling-Computer Simulations At Walker-Lane Transitional Zone...
navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Walker-Lane Transitional Zone Region (Biasi, Et Al., 2009) Exploration...
Modeling-Computer Simulations At Long Valley Caldera Geothermal...
navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Long Valley Caldera Geothermal Area (Tempel, Et Al., 2011) Exploration...
Modeling-Computer Simulations At Northern Basin & Range Region...
navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Northern Basin & Range Region (Biasi, Et Al., 2009) Exploration...
Modeling-Computer Simulations At Northern Basin & Range Region...
Northern Basin and Range Geothermal Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not indicated DOE-funding Unknown References J. W. Pritchett...
Modeling-Computer Simulations At Dixie Valley Geothermal Area...
Modeling-Computer Simulations At Dixie Valley Geothermal Area (Kennedy & Soest, 2006) Exploration Activity Details Location Dixie Valley Geothermal Area Exploration Technique...
Modeling-Computer Simulations At Kilauea East Rift Geothermal...
navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Kilauea East Rift Geothermal Area (Rudman & Epp, 1983) Exploration...
Modeling-Computer Simulations At Walker-Lane Transitional Zone...
navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Walker-Lane Transitional Zone Region (Pritchett, 2004) Exploration...
Modeling-Computer Simulations At Nw Basin & Range Region (Pritchett...
navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Nw Basin & Range Region (Pritchett, 2004) Exploration Activity Details...
Modeling-Computer Simulations At Valles Caldera - Sulphur Springs...
navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Valles Caldera - Sulphur Springs Geothermal Area (Wilt & Haar, 1986)...
Modeling-Computer Simulations At Dixie Valley Geothermal Area...
navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Dixie Valley Geothermal Area (Wannamaker, Et Al., 2006) Exploration...
Modeling-Computer Simulations At Fish Lake Valley Area (Deymonaz...
Additional References Retrieved from "http:en.openei.orgwindex.php?titleModeling-ComputerSimulationsAtFishLakeValleyArea(Deymonaz,EtAl.,2008)&oldid387627...
Modeling-Computer Simulations At U.S. West Region (Williams ...
Modeling-Computer Simulations At U.S. West Region (Williams & Deangelo, 2008) Exploration Activity Details Location U.S. West Region Exploration Technique Modeling-Computer...
Numerical Simulations in Cosmology I
A. Klypin
1996-05-30T23:59:59.000Z
The purpose of these lectures is to give a short introduction into a very vast field of numerical simulations for cosmological applications. I focus on major features of the simulations: the equations, main numerical techniques, effects of resolution, and methods of halo identification.
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...
Numerical Simulations of Thermobaric Explosions
Kuhl, A L; Bell, J B; Beckner, V E; Khasainov, B
2007-05-04T23:59:59.000Z
A Model of the energy evolution in thermobaric explosions is presented. It is based on the two-phase formulation: conservation laws for the gas and particle phases along with inter-phase interaction terms. It incorporates a Combustion Model based on the mass conservation laws for fuel, air and products; source/sink terms are treated in the fast-chemistry limit appropriate for such gas dynamic fields. The Model takes into account both the afterburning of the detonation products of the booster with air, and the combustion of the fuel (Al or TNT detonation products) with air. Numerical simulations were performed for 1.5-g thermobaric explosions in five different chambers (volumes ranging from 6.6 to 40 liters and length-to-diameter ratios from 1 to 12.5). Computed pressure waveforms were very similar to measured waveforms in all cases - thereby proving that the Model correctly predicts the energy evolution in such explosions. The computed global fuel consumption {mu}(t) behaved as an exponential life function. Its derivative {dot {mu}}(t) represents the global rate of fuel consumption. It depends on the rate of turbulent mixing which controls the rate of energy release in thermobaric explosions.
Numerical Simulation of Cooling Gas Injection Using
Numerical Simulation of Cooling Gas Injection Using Adaptive Multiscale Techniques Wolfgang Dahmen: finite volume method, film cooling, cooling gas injection, multiscale techniques, grid adaptation AMS@igpm.rwth-aachen.de (Thomas Gotzen) #12;Numerical simulation of cooling gas injection using adaptive multiscale techniques
Comparing Aerodynamic Models for Numerical Simulation of
Peraire, Jaime
Comparing Aerodynamic Models for Numerical Simulation of Dynamics and Control of Aircraft and simulation of aircraft, yet other aerodynamics models exist that can provide more accurate results for certain simulations without a large increase in computational time. In this paper, sev- eral aerodynamics
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.
Issues in Numerical Simulation of Fire Suppression
Tieszen, S.R.; Lopez, A.R.
1999-04-12T23:59:59.000Z
This paper outlines general physical and computational issues associated with performing numerical simulation of fire suppression. Fire suppression encompasses a broad range of chemistry and physics over a large range of time and length scales. The authors discuss the dominant physical/chemical processes important to fire suppression that must be captured by a fire suppression model to be of engineering usefulness. First-principles solutions are not possible due to computational limitations, even with the new generation of tera-flop computers. A basic strategy combining computational fluid dynamics (CFD) simulation techniques with sub-grid model approximations for processes that have length scales unresolvable by gridding is presented.
Numerical Simulations of Hyperfine Transitions of Antihydrogen
Kolbinger, B; Diermaier, M; Lehner, S; Malbrunot, C; Massiczek, O; Sauerzopf, C; Simon, M C; Widmann, E
2015-01-01T23:59:59.000Z
One of the ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons) collaboration's goals is the measurement of the ground state hyperfine transition frequency in antihydrogen, the antimatter counterpart of one of the best known systems in physics. This high precision experiment yields a sensitive test of the fundamental symmetry of CPT. Numerical simulations of hyperfine transitions of antihydrogen atoms have been performed providing information on the required antihydrogen events and the achievable precision.
NEW NUMERICAL TECHNOLOGIES FOR THE SIMULATION OF ARC WELDING PROCESSES
Paris-Sud XI, UniversitÃ© 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 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.
Numerical Simulation of Unsteady Three-Dimensional Sheet Cavitation
Twente, Universiteit
Numerical Simulation of Unsteady Three-Dimensional Sheet Cavitation A.H. Koop #12;Numerical Simulation of Unsteady Three-Dimensional Sheet Cavitation A.H. Koop Thesis University of Twente, Enschede, the Netherlands #12;NUMERICAL SIMULATION OF UNSTEADY THREE-DIMENSIONAL SHEET CAVITATION PROEFSCHRIFT ter
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.
Numerical simulation of detonation failure in nitromethane
Kipp, M.E.; Nunziato, J.W.
1981-01-01T23:59:59.000Z
Detonation failure in the homogeneous liquid explosive nitromethane has been observed experimentally in a wide variety of confining geometries. However, numerical simulation of these failure situations with a wave propagation code has been essentially non-existent due to the large differences between the critical diameter and the length of the reaction zone - characteristic dimensions which differ by about two orders of magnitude. This inability to spatially resolve both the reaction zone and geometries of significant size has led us to propose a new numerical technique, based on the stability criterion for rate-type material models, in which only temporal resolution of the reaction zone is required. Using an improved model for nitromethane, we have carried out a series of two-dimensional calculations which illustrate the utility of the present approach in predicting a wide range of experimental observations. Of particular computational significance is the removal of the difficulty requiring spatial resolution of the reaction zone, so that problems of practical size can be analyzed with existing computer capabilities.
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.
On the Numerical Simulation of Waterflooding of Heterogeneous
Douglas Jr., Jim
On the Numerical Simulation of Waterflooding of Heterogeneous Petroleum Reservoirs Jim Douglas, Jr displacement in petroleum reservoirs. A very detailed description of the numerical method is presented. Follow, 22290 Rio de Janeiro, RJ, Brazil #12; On the Numerical Simulation of Waterflooding of Heterogeneous
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 and Robust Predictions of Cloud...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
the center of the bubble cloud. Credit: Computational Science and Engineering Laboratory, ETH Zurich, Switzerland Direct Numerical Simulations and Robust Predictions of Cloud...
Direct Numerical Simulations in Engine-like Geometries | Argonne...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Direct Numerical Simulations in Engine-like Geometries Event Sponsor: Mathematics and Computing ScienceArgonne Leadership Computing Facility Seminar Start Date: Nov 14 2014 -...
Numerical simulation of transpiration cooling through porous , T. Gotzen1
55, 52056 Aachen SUMMARY Transpiration cooling using ceramic matrix composite (CMC) materials to facilitate such numerical simulations for a carbon/carbon material mounted in the side wall of a hot gasNumerical simulation of transpiration cooling through porous material W. Dahmen1 , T. Gotzen1 and S
Numerical Simulation of Wave Loads on Static Offshore Structures
Numerical Simulation of Wave Loads on Static Offshore Structures Hrvoje Jasak, Inno Gatin, Vuko Workshop, Cambridge, 30 July 2014 Numerical Simulation of Wave Loads on Static Offshore Structures Â p. #12 of Wave Loads on Static Offshore Structures Â p. #12;VOF Free Surface Flow Model Modelling of Free Surface
Plasma astrophysics in numerical simulations A. Nordlund
Brandenburg, Axel
in periodic domains are discussed. Modifications of the solutions by numerically motivated alterations-excited dynamos were invented by the Danish inventor SÃ¸ren Hjorth, who received the patent for this discovery industrial importance in producing the most powerful generators at the time, for which he, in turn, received
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-310 825 1715/2599. E-mail address: ying@fusion.ucla.edu (A. Ying). 0022-3115/02/$ - see front matter Ã?
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 of flow separation control by oscillatory fluid injection
Resendiz Rosas, Celerino
2005-08-29T23:59:59.000Z
NUMERICAL SIMULATION OF FLOW SEPARATION CONTROL BY OSCILLATORY FLUID INJECTION A Dissertation by CELERINO RESENDIZ ROSAS Submitted to the O?ce of Graduate Studies of Texas A&M University in partial ful?llment of the requirements for the degree... of DOCTOR OF PHILOSOPHY May 2005 Major Subject: Aerospace Engineering NUMERICAL SIMULATION OF FLOW SEPARATION CONTROL BY OSCILLATORY FLUID INJECTION A Dissertation by CELERINO RESENDIZ ROSAS Submitted to Texas A&M University in partial ful...
A Mobile Computing Architecture for Numerical Simulation Cyril Dumont
Paris-Sud XI, UniversitÃ© de
A Mobile Computing Architecture for Numerical Simulation Cyril Dumont Paris 12 University LACL of a numeric computation have to react when their context changes. This paper offers a new architecture, a mobile computing architecture, based on mobile agents and JavaSpace. At the end of this paper, we apply
Numerical Simulation of a Natural Circulation Steam Generator
WeinmÃ¼ller, 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 techniques of rigid body simulation
Eberle, David Michael
2012-06-07T23:59:59.000Z
of the body, we need to know how x(t) and R(t) change over time. The linear velocity v(t) and the angular velocity w(t) clescribc this change. It is clear that v(t) frn(t) results in translation and that w(t) changes the orientation. In onr simulator ~~u...
On the Numerical Simulation of Waterflooding of Heterogeneous
Furtado, Fred
On the Numerical Simulation of Waterflooding of Heterogeneous Petroleum Reservoirs Jim Douglas, Jr Simulation of Waterflooding of Heterogeneous Petroleum Reservoirs Â· A two-stage operator-splitting allows consider as a model problem the two-phase immiscible displacement in petroleum reservoirs. A very detailed
Efficient Numerical Simulation for Long Range Wave Propagation 1
Solna, Knut
Efficient Numerical Simulation for Long Range Wave Propagation 1 Kai Huang 2 George Papanicolaou 3 for simulating wave propagation over long dis- tances with both weak and strong scatterers. In domains with weak heterogeneities the wave field is decomposed into forward propagating and back scattered modes using two coupled
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.
Numerical simulation of imbibition process in fractured cores
Jiang, Chunhuan
1992-01-01T23:59:59.000Z
of the equations describing the imbibition of pure and carbonated water and the countercurrent flow of oil in porous rocks. Comparison between numerical solutions and experimental observations indicates that the models do simulate water imbibition and the COp.... ~~ +Blair 1964 presented a numerical solution for equations describing oil displacement by countercurrent water imbibition. Calculations were made for water imbibition into both linear and radial systems. Blair studied the effects on imbibition rates as a...
Numerical simulation of water flow around a rigid fishing net
Roger Lewandowski; Géraldine Pichot
2006-12-20T23:59:59.000Z
This paper is devoted to the simulation of the flow around and inside a rigid axisymmetric net. We describe first how experimental data have been obtained. We show in detail the modelization. The model is based on a Reynolds Averaged Navier-Stokes turbulence model penalized by a term based on the Brinkman law. At the out-boundary of the computational box, we have used a "ghost" boundary condition. We show that the corresponding variational problem has a solution. Then the numerical scheme is given and the paper finishes with numerical simulations compared with the experimental data.
Numerical simulation of the truss spar 'Horn Mountain' using COUPLE
Theckum Purath, Basil
2006-08-16T23:59:59.000Z
using an integrated marine monitoring system attached to the truss spar. In this study, dynamic analysis of the truss spar interacting with its mooring and riser system was performed using a time-domain numerical code, known as Â?COUPLEÂ?. The simulated...
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
Carmignani, B
2005-01-01T23:59:59.000Z
Numerical simulations of welds of thick steel pieces of interest for the thermonuclear fusion ITER machine
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...
Numerical simulations of gravitational collapse in Einstein-aether theory
David Garfinkle; Christopher Eling; Ted Jacobson
2007-07-01T23:59:59.000Z
We study gravitational collapse of a spherically symmetric scalar field in Einstein-aether theory (general relativity coupled to a dynamical unit timelike vector field). The initial value formulation is developed, and numerical simulations are performed. The collapse produces regular, stationary black holes, as long as the aether coupling constants are not too large. For larger couplings a finite area singularity occurs. These results are shown to be consistent with the stationary solutions found previously.
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.
Hydrodynamics of Hypersonic Jets: Experiments and Numerical Simulations
Belan, Marco; Tordella, Daniela; Massaglia, Silvano; Ferrari, Attilio; Mignone, Andrea; Bodenschatz, Eberhard
2011-01-01T23:59:59.000Z
Stars form in regions of the galaxy that are denser and cooler than the mean interstellar medium. These regions are called Giant Molecular Clouds. At the beginning of their life, up to $10^5-10^6$ years, stars accrete matter from their rich surrounding environment and are origin of a peculiar phenomenon that is the jet emission. Jets from Young Stellar Objects (YSOs) are intensively studied by the astrophysical community by observations at different wavelengths, analytical and numerical modeling and laboratory experiments. Indications about the jet propagation and its resulting morphologies are here obtained by means of a combined study of hypersonic jets carried out both in the laboratory and by numerical simulations.
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.
Numerical simulation of the Tayler instability in liquid metals
Weber, Norbert; Stefani, Frank; Weier, Tom; Wondrak, Thomas
2012-01-01T23:59:59.000Z
The electrical current through an incompressible, viscous and resistive liquid conductor produces an azimuthal magnetic field that becomes unstable when the corresponding Hartmann number exceeds a critical value in the order of 20. This Tayler instability, which is not only discussed as a key ingredient of a non-linear stellar dynamo model (Tayler-Spruit dynamo), but also as a limiting factor for the maximum size of large liquid metal batteries, was recently observed experimentally in a column of a liquid metal (Seilmayer et al., Phys. Rev. Lett. 108, 244501, 2012}. On the basis of an integro-differential equation approach, we have developed a fully three-dimensional numerical code, and have utilized it for the simulation of the Tayler instability at typical viscosities and resistivities of liquid metals. The resulting growth rates are in good agreement with the experimental data. We illustrate the capabilities of the code for the detailed simulation of liquid metal battery problems in realistic geometries.
Kinetic theory and numerical simulations of two-species coagulation
Carlos Escudero; Fabricio Macia; Raul Toral; Juan J. L. Velazquez
2014-04-19T23:59:59.000Z
In this work we study the stochastic process of two-species coagulation. This process consists in the aggregation dynamics taking place in a ring. Particles and clusters of particles are set in this ring and they can move either clockwise or counterclockwise. They have a probability to aggregate forming larger clusters when they collide with another particle or cluster. We study the stochastic process both analytically and numerically. Analytically, we derive a kinetic theory which approximately describes the process dynamics. One of our strongest assumptions in this respect is the so called well-stirred limit, that allows neglecting the appearance of spatial coordinates in the theory, so this becomes effectively reduced to a zeroth dimensional model. We determine the long time behavior of such a model, making emphasis in one special case in which it displays self-similar solutions. In particular these calculations answer the question of how the system gets ordered, with all particles and clusters moving in the same direction, in the long time. We compare our analytical results with direct numerical simulations of the stochastic process and both corroborate its predictions and check its limitations. In particular, we numerically confirm the ordering dynamics predicted by the kinetic theory and explore properties of the realizations of the stochastic process which are not accessible to our theoretical approach.
Numerical Relativity in Spherical Polar Coordinates: Off-center Simulations
Thomas W. Baumgarte; Pedro J. Montero; Ewald Müller
2015-01-21T23:59:59.000Z
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 Relativity in Spherical Polar Coordinates: Off-center Simulations
Baumgarte, Thomas W; Müller, Ewald
2015-01-01T23:59:59.000Z
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 parti...
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...
Griebel, Michael
, says: "The power supplies and the cooling systems could not cope with the constant heavy loads of data computer networks supplied by specialist organisations have performed the institute's numerical simulation
Numerical simulation of linear fiction welding (LFW) processes
Fratini, L.; La Spisa, D. [University of Palermo-Dept. of Industrial engineering (Italy)
2011-05-04T23:59:59.000Z
Solid state welding processes are becoming increasingly important due to a large number of advantages related to joining ''unweldable'' materials and in particular light weight alloys. Linear friction welding (LFW) has been used successfully to bond non-axisymmetric components of a range of materials including titanium alloys, steels, aluminum alloys, nickel, copper, and also dissimilar material combinations. The technique is useful in the research of quality of the joints and in reducing costs of components and parts of the aeronautic and automotive industries.LFW involves parts to be welded through the relative reciprocating motion of two components under an axial force. In such process the heat source is given by the frictional forces work decaying into heat determining a local softening of the material and proper bonding conditions due to both the temperature increase and the local pressure of the two edges to be welded. This paper is a comparative test between the numerical model in two dimensions, i.e. in plane strain conditions, and in three dimensions of a LFW process of AISI1045 steel specimens. It must be observed that the 3D model assures a faithful simulation of the actual threedimensional material flow, even if the two-dimensional simulation computational times are very short, a few hours instead of several ones as the 3D model. The obtained results were compared with experimental values found out in the scientific literature.
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...
Numerical simulation of laminar flow in a curved duct
Lopez, A.R.; Oberkampf, W.L.
1995-01-01T23:59:59.000Z
This paper describes numerical simulations that were performed to study laminar flow through a square duct with a 900 bend. The purpose of this work was two fold. First, an improved understanding was desired of the flow physics involved in the generation of secondary vortical flows in three-dimensions. Second, adaptive gridding techniques for structured grids in three- dimensions were investigated for the purpose of determining their utility in low Reynolds number, incompressible flows. It was also of interest to validate the commercial computer code CFD-ACE. Velocity predictions for both non-adaptive and adaptive grids are compared with experimental data. Flow visualization was used to examine the characteristics of the flow though the curved duct in order to better understand the viscous flow physics of this problem. Generally, moderate agreement with the experimental data was found but shortcomings in the experiment were demonstrated. The adaptive grids did not produce the same level of accuracy as the non-adaptive grid with a factor of four more grid points.
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
Zhang, Xiong
2005-11-01T23:59:59.000Z
and numerical techniques: different simulation methods for different boundary conditions such as tree, grass, and bare soils, coupled hydro-mechanical stress analysis to describe deformation of saturated-unsaturated soils, jointed elements simulation of soil...
Direct Numerical Simulation of a Hypersonic Turbulent Boundary Layer on a Large Domain
MartÃn, Pino
Direct Numerical Simulation of a Hypersonic Turbulent Boundary Layer on a Large Domain Stephan Priebe , M. Pino MartÂ´in The direct numerical simulation (DNS) of a spatially-developing hypersonic There are few studies of hypersonic flows at Mach number greater than 5 and few involve the measurement of mean
Hellman, Frances
Numerical simulation of the heat transfer in amorphous silicon nitride membrane July 2003 Numerical simulations of the two-dimensional 2D heat flow in a membrane-based microcalorimeter have been performed. The steady-state isotherms and time-dependent heat flow have been calculated
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
Clement, Prabhakar
Comparison of Numerical Techniques Used for Simulating Variable-Density Flow and Transport code by simulating two new variable-density-flow and transport experimental data sets. The experiments transport of a sinking groundwater plume and a rising groundwater plume. The numerical techniques used
OBJECT ORIENTED PROGRAMMING TECHNIQUES AND FAC METHOD IN NUMERICAL RESERVOIR SIMULATION \\Lambda
OBJECT ORIENTED PROGRAMMING TECHNIQUES AND FAC METHOD IN NUMERICAL RESERVOIR SIMULATION \\Lambda in numerical simulation of flow through hydrocarbon reservoirs within limitations in computing time and memory. These consist of solution of the conservation equations whichs govern the motion of fluid through the reservoir
t -software package for numerical simulations of radioactive contaminant transport in groundwater
Frolkovic, Peter
r3 t - software package for numerical simulations of radioactive contaminant transport equations that arise from the modelling of radioactive contaminant transport in porous media. It can solve, see [6]) can help to numerically simulate the spreading of radioactive contaminants in flowing ground
Corigliano, Alberto
Experimental characterization and numerical simulations of a syntactic-foam/glass-Â®bre composite core. Such core consists of a syntactic foam made by hollow glass microspheres embedded in an epoxy. Keywords: A. Glass Â®bre; Composite sandwich; Syntactic foam; Mechanical tests; Numerical simulations (FE) 1
Adaptive higher order numerical simulation of heat and mass transfer in fluidized beds
Magdeburg, UniversitÃ¤t
Adaptive higher order numerical simulation of heat and mass transfer in fluidized beds Ch. Nagaiah1 adaptive numerical results of heat and mass transfer in fluidized beds using higher order time stepping injection. The numerical results are tested with different time stepping methods for different spatial grid
Numerical Simulation of Cold Pressing of Armstrong CP-Ti Powders
Sabau, Adrian S [ORNL] [ORNL; Gorti, Sarma B [ORNL] [ORNL; Peter, William H [ORNL] [ORNL; Chen, Wei [ORNL] [ORNL; Yamamoto, Yukinori [ORNL] [ORNL
2012-01-01T23:59:59.000Z
Numerical simulation results for the cold pressing of Armstrong CP-Ti Powders are presented. The computational model was implemented in the commercial finite element program ABAQUSTM. Several simulation cases were conducted for cylindrical samples with different friction coefficients and different compaction pressures, under both single-action and dual-action uniaxial pressing. Numerical simulation results for the density distribution are compared against experimental data in order to validate the computational model.
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 simulations of self-focusing of ultrafast laser pulses Gadi Fibich*
Wang, Xiao-Ping
Numerical simulations of self-focusing of ultrafast laser pulses Gadi Fibich* School November 2002; published 7 May 2003 Simulation of nonlinear propagation of intense ultrafast laser pulses, space-time focusing, and self-steepening. Our simulations show that, after the asymmetric temporal pulse
Determination of SNe explosions frequency distribution function.Method and numerical simulations
A. A. Akopian
2007-05-03T23:59:59.000Z
The method for determination of the Supernovae (SNe) explosions frequency distribution function based on the assumption of explosions independence are offered. The method is based on assumption that the sequence of SNe explosions in an individual galaxy is a Poisson sequence. The essence of the method is in the determination of statistical moments of the frequency of the SNe explosions and subsequent determination of distribution function . The program of numerical simulation has been developed for testing the efficiency of the method. Numerical simulations show that even for a small mean number of registered SNe explosions, method allows restoring initial distribution function. The results of numerical simulations are given.
Numerical simulation of fluid flow in porous/fractured media
Travis B.J.; Cook, T.L.
1981-01-01T23:59:59.000Z
Theoretical models of fluid flow in porous/fractured media can help in the design of in situ fossil energy and mineral extraction technologies. Because of the complexity of these processes, numerical solutions are usually required. Sample calculations illustrate the capabilities of present day computer models.
Neutrino Factory / Muon Collider Target Meeting Numerical Simulations for Jet-Proton
McDonald, Kirk
breakup observed in simulations Mercury is able to sustain very large tension Jet oscillates after on the surface of a hydrofoil Pressure contour in mercury target. #12;13 The Bubble Insertion Model Numerical
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 ...
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 Simulation of Enhanced Mixing in Scramjet Combustor Using Ramp, Tabs and Suction Collar
Hwang, Seung-Jae
2011-06-09T23:59:59.000Z
Numerical simulations of the scramjet combustor by using the commercial CFD code Fluent with the coupled implicit method with second-order accurate discretization have been obtained for the reacting flows with the parallel fuel injection (ramp...
Numerical simulation of the response of sandy soils treated with pre-fabricated vertical drains
Vytiniotis, Antonios
2009-01-01T23:59:59.000Z
This research is part of the ongoing effort of the Seismic Risk Mitigation for Port Systems Grand Challenge. It addresses the problem of numerically simulating the response of sandy soils treated with earthquake drains, ...
Bordry, Frederick; Proudlock, Paul
1988-01-01T23:59:59.000Z
Numeric simulation of thyristor power converters taking into consideration the firing-circuits and the closed-loop control
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 large amplitude liquid sloshing in a rigid rectangular tank
Bridges, Thomas J.
1981-01-01T23:59:59.000Z
NUMERICAL SIMULATION OF LARGE AMPLITUDE LIQUID SLOSHING IN A RIGID RECTANGULAR TANK A Thesis by THOMAS JACKSON BRIDGES Submitted to the Graduate College of Texas A8M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIE'ICE December 1981 Major Subject: Ocean Engineering NUMERICAL SIMULATION OF LARGE AMPLITUDE LIQUID SLOSHING IN A RIGID RECTANGULAR TANK A Thesis by THOMAS JACKSON BRIDGES Approved as to sty1e and content by: (Chairman of Commit ee...
Separation phenomena in the tritium source and numerical simulations of turbo-molecular pumps
Sharipov, Felix
Separation phenomena in the tritium source and numerical simulations of turbo-molecular pumps Felix In the previous works [1, 2], the results of numerical calculations of tritium flow from the buffer vessel up to the first vacuum system were reported. Two values of the tritium source temperature were considered, i.e. 27
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
Pierre, Charles
Context DDFV Scheme Numerical analysis ECG Simulation 2D/3D DDFV scheme for anisotropic Numerical analysis ECG Simulation Authors : Laboratoire de mathÂ´ematiques Jean Leray, UniversitÂ´e de Nantes Pays de l'Adour : Â· Charles Pierre #12;Context DDFV Scheme Numerical analysis ECG Simulation Outline
Numerical Simulation of Titanium Production in the Plasma Quench Reactor
. The method is directly applicable to simulation of condensation of other metals in other gas flows. We is the condensation of nanoclusters from the gas phase, e.g. condensation of metal (or ceramic) vapors in a low the nucleation of condensates in the steady-state supersonic nozzle flow generated in a plasma quench reactor
Numerical Simulation in Applied Geophysics. From the Mesoscale to ...
2013-07-05T23:59:59.000Z
Instituto del Gas y del Petr´oleo, Facultad de Ingenier?a UBA. †,†. Facultad de ... hydrocarbon exploration geophysics, mining and reservoir characterization and production. Local variations in the fluid ... physical process of wave propagation can be inspected during the experiment. ..... Black-Oil simulator. CO2 saturation ...
A Model and Numerical Framework for the Simulation of Solid-Solid Phase Transformations
Govindjee, Sanjay
A Model and Numerical Framework for the Simulation of Solid-Solid Phase Transformations Garrett J computational realization for the simulation of solid-solid phase transformations of the type observed in shape physical experiments and is indicative of the power of the proposed modelling methodology. In particular
EXPLICIT SIMULATION OF ICE PARTICLE HABITS IN A NUMERICAL WEATHER PREDICTION MODEL
Wisconsin at Madison, University of
EXPLICIT SIMULATION OF ICE PARTICLE HABITS IN A NUMERICAL WEATHER PREDICTION MODEL by Tempei This study develops a scheme for explicit simulation of ice particle habits in Cloud Resolving Models (CRMs is called Spectral Ice Habit Prediction System (SHIPS), which represents a continuous-property approach
A Numerical Model for the Dynamic Simulation of a Recirculation Single-Effect Absorption Chiller
Paris-Sud XI, UniversitÃ© de
A Numerical Model for the Dynamic Simulation of a Recirculation Single- Effect Absorption Chiller A dynamic model for the simulation of a new single-effect water/lithium bromide absorption chiller is developed. The chiller is driven by two distinct heat sources, includes a custom integrated falling film
DIRECT NUMERICAL SIMULATION OF COMPRESSIBLE TRANSITION: AN OVERVIEW M.Y. Hussaini and G. Erlebacher
Erlebacher, Gordon
DIRECT NUMERICAL SIMULATION OF COMPRESSIBLE TRANSITION: AN OVERVIEW M.Y. Hussaini and G. Erlebacher in the field of compressible transition. As a result, new computational tools have made their appearance. Recently however, research at Langley has begun to focus on the simulation of compressible transition
Direct numerical simulation of autoignition of a hydrogen vortex ring reacting with hot air
Mahesh, Krishnan
Direct numerical simulation of autoÂignition of a hydrogen vortex ring reacting with hot air Jeff2/air combustion proposed by Mueller et al. [2]. Diluted H2 at ambient temperature (300 K) is injected into hot air. The simulations study the effect of fuel/air ratios, oxidizer temperature, Lewis
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 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.
Numerical Simulation of Bubble Formation in Co-Flowing Mercury
Abdou, Ashraf A [ORNL; Wendel, Mark W [ORNL; Felde, David K [ORNL; Riemer, Bernie [ORNL
2008-01-01T23:59:59.000Z
In this work, we present computational fluid dynamics (CFD) simulations of helium bubble formation and detachment at a submerged needle in stagnant and co-flowing mercury. Since mercury is opaque, visualization of internal gas bubbles was done with proton radiography (pRad) at the Los Alamos Neutron Science Center (LANSCE2). The acoustic waves emitted at the time of detachment and during subsequent oscillations of the bubble were recorded with a microphone. The Volume of Fluid (VOF) model was used to simulate the unsteady two-phase flow of gas injection in mercury. The VOF model is validated by comparing detailed bubble sizes and shapes at various stages of the bubble growth and detachment, with the experimental measurements at different gas flow rates and mercury velocities. The experimental and computational results show a two-stage bubble formation. The first stage involves growing bubble around the needle, and the second follows as the buoyancy overcomes wall adhesion. The comparison of predicted and measured bubble sizes and shapes at various stages of the bubble growth and detachment is in good agreement.
Study on Applicability of Numerical Simulation to Evaluation of Gas Entrainment From Free Surface
Kei Ito; Takaaki Sakai; Hiroyuki Ohshima [Japan Atomic Energy Agency (Japan)
2006-07-01T23:59:59.000Z
An onset condition of gas entrainment (GE) due to free surface vortex has been studied to establish a design of fast breeder reactor with higher coolant velocity than conventional designs, because the GE might cause the reactor operation instability and therefore should be avoided. The onset condition of the GE has been investigated experimentally and theoretically, however, dependency of the vortex type GE on local geometry configuration of each experimental system and local velocity distribution has prevented researchers from formulating the universal onset condition of the vortex type GE. A real scale test is considered as an accurate method to evaluate the occurrence of the vortex type GE, but the real scale test is generally expensive and not useful in the design study of large and complicated FBR systems, because frequent displacement of inner equipments accompanied by the design change is difficult in the real scale test. Numerical simulation seems to be promising method as an alternative to the real scale test. In this research, to evaluate the applicability of the numerical simulation to the design work, numerical simulations were conducted on the basic experimental system of the vortex type GE. This basic experiment consisted of rectangular flow channel and two important equipments for vortex type GE in the channel, i.e. vortex generation and suction equipments. Generated vortex grew rapidly interacting with the suction flow and the grown vortex formed a free surface dent (gas core). When the tip of the gas core or the bubbles detached from the tip of the gas core reached the suction mouth, the gas was entrained to the suction tube. The results of numerical simulation under the experimental conditions were compared to the experiment in terms of velocity distributions and free surface shape. As a result, the numerical simulation showed qualitatively good agreement with experimental data. The numerical simulation results were similar to the experimental results in terms of the shape of free surface dent and the velocity distribution around the vortex, although the GE itself was not completely reproduced due to a lack of enough mesh partition. After confirming the applicability of the numerical simulation to the GE evaluation, several parameters, such as suction velocity and a configuration around suction mouth, were numerically examined to evaluate their influence on the GE. The tendencies of the GE occurrence enhanced by larger suction velocity or suction mouth on bottom surface enhance occurrence of the GE were obtained from the simulation results. These simulation results implied that the numerical simulation has enough potential to be used for the design work. (authors)
Numerical simulation of scour process around bridge piers in cohesive soil
Wei, Gengsheng
1997-01-01T23:59:59.000Z
of streambed materials is also necessary. Consequently, progresses are very limitted in this area. Numerical computation of bridge pier scour in noncohesive soils can only be found in Olsen and Melaaen (1993) and Olsen (1996), and no reference exists... in numerical simulations of scour process. Furthermore, all the references are confined to noncohesive soils. Olsen and Melaaen (1993) calculated the shape of a scour hole around a cylinder mounted in a noncohesive streambed. They used a three...
Meador, Charles Michael
2011-02-22T23:59:59.000Z
MASSIVELY-PARALLEL DIRECT NUMERICAL SIMULATION OF GAS TURBINE ENDWALL FILM-COOLING CONJUGATE HEAT TRANSFER A Thesis by CHARLES MICHAEL MEADOR Submitted to the O ce of Graduate Studies of Texas A&M University in partial ful llment of the requirements... for the degree of MASTER OF SCIENCE December 2010 Major Subject: Mechanical Engineering MASSIVELY-PARALLEL DIRECT NUMERICAL SIMULATION OF GAS TURBINE ENDWALL FILM-COOLING CONJUGATE HEAT TRANSFER A Thesis by CHARLES MICHAEL MEADOR Submitted to the O ce of Graduate...
Numerical simulation of noise generated by multi asperity contact between rough surfaces
Paris-Sud XI, UniversitÃ© de
. The validation of the method is then discussed by comparison with the finite element software Abaqus and someNumerical simulation of noise generated by multi asperity contact between rough surfaces V.H. Dang at the interface that convert a part of the kinetic energy of the sliding solid into acoustical energy. 1
Review Numerically exact computer simulations of light scattering by densely packed, random Astronomical Observatory of the National Academy of Sciences of Ukraine, 27 Zabolotny Street, 03680 Kyiv- albedo Solar System objects are caused by CB. Published by Elsevier Ltd. Contents 1. Introduction
Numerical simulation of a lattice polymer model at its integrable point
A. Bedini; A. L. Owczarek; T. Prellberg
2013-05-21T23:59:59.000Z
We revisit an integrable lattice model of polymer collapse using numerical simulations. This model was first studied by Bl\\"ote and Nienhuis in J. Phys. A. {\\bf 22}, 1415 (1989) and it describes polymers with some attraction, providing thus a model for the polymer collapse transition. At a particular set of Boltzmann weights the model is integrable and the exponents $\
PHYSICS OF FLUIDS 24, 103306 (2012) Numerical simulation of turbulent sediment transport,
Claudin, Philippe
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), vertical velocities are so small that sediment transport occurs in a thin layer at the surface
Numerical simulation and sensitivity study of a severe hailstorm in northeast Spain
Romero, Romu
Numerical simulation and sensitivity study of a severe hailstorm in northeast Spain E. GarcÃa AtmÃ³sfera, Instituto de Medio Ambiente, Universidad de LeÃ³n, 24071 LeÃ³n, Spain b Grup de Meteorologia, Departament de FÃsica, Universitat de les Illes Balears, Palma de Mallorca, Spain Accepted 8 August 2005
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
Numerical simulations of heat transfer in plane channel flow Najla EL GHARBI 1, 3, a
Paris-Sud XI, UniversitÃ© de
Numerical simulations of heat transfer in plane channel flow Najla EL GHARBI 1, 3, a , Rafik ABSI 2 abenzaoui@gmail.com Keywords: turbulent flows, heat transfer, forced convection, low Reynolds number model data for Re = 150. Introduction Turbulent flow with heat transfer mechanism is of great importance from
Harting, Jens
by a cooling system to guarantee their appropriate performance. One possible way to cool these devises canEulerianÂEulerian 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
Numerical simulations of the thermal impact of supercritical CO2 injection on chemical
Boyer, Edmond
Numerical simulations of the thermal impact of supercritical CO2 injection on chemical reactivity, investigates thermal effects during CO2 injection into a deep carbonate formation. Different thermal processes in carbonate aquifers, and the influence of anthropic thermal processes (e.g., injection temperature
DIVERGENCE-FREE AND CURL-FREE WAVELETS ON THE SQUARE FOR NUMERICAL SIMULATIONS
Boyer, Edmond
DIVERGENCE-FREE AND CURL-FREE WAVELETS ON THE SQUARE FOR NUMERICAL SIMULATIONS SOULEYMANE KADRI Grenoble cedex 9, France August 30, 2011 Abstract We present a construction of divergence-free and curl-free and integration. We introduce new BMRAs and wavelets for the spaces of divergence-free and curl-free vector
Adegbesan, K.O.; Donnelly, J.K.; Moore, R.G.; Bennion, D.W.
1986-08-01T23:59:59.000Z
Multiresponse kinetic models are established for the low-temperature oxidation (LTO) reaction of Athabasca oil sands bitumen. The models provide adequate description of the overall rate of oxygen consumption and of the reactions of the liquid phase bitumen components. The LTO models are suitable for use in the in situ combustion numerical simulators of oil sands.
LIDAR OBSERVATIONS AND COMPARISON WITH NUMERICAL SIMULATION OF A LAKE MICHIGAN LAND BREEZE FRONT
Eloranta, Edwin W.
of the Lake-Induced Convection Experiments (Lake-ICE), on December 21, 1997 the University of Wisconsin VolumeLIDAR OBSERVATIONS AND COMPARISON WITH NUMERICAL SIMULATION OF A LAKE MICHIGAN LAND BREEZE FRONT G circulation over Lake Michigan. Backscatter returns revealed a steady offshore flow extending 1.5 to 4 km
Direct numerical simulation of an iron rain in the magma ocean
Paris-Sud XI, UniversitÃ© de
investigate the conversion of gravitational energy into viscous heating and the thermal equilibration betweenDirect numerical simulation of an iron rain in the magma ocean H. Ichikawa,1,2 S. Labrosse,1 and K of metal in a magma ocean. The model, using a fully Lagrangian approach called the moving particle semi
Ducted Turbine Blade Optimization Using Numerical Simulation Michael Shives and Curran Crawford
Pedersen, Tom
Ducted Turbine Blade Optimization Using Numerical Simulation Michael Shives and Curran Crawford analysis and optimization of ducted turbines. The model is similar to standard blade element momentum. This eliminates many assumptions used in applying the typical blade element momentum (BEM) theory to a turbine
Wang, Yuqing
0 Energy Production, Frictional Dissipation, and Maximum Intensity of a Numerically Simulated) viewed as a heat engine converts heat energy extracted from the ocean to kinetic energy of the TC, which is eventually dissipated due to surface friction. Since the energy production rate is a linear function while
Wang, Yuqing
Energy Production, Frictional Dissipation, and Maximum Intensity of a Numerically Simulated as a heat engine converts heat energy extracted from the ocean into the kinetic energy of the TC, which is eventually dissipated due to surface friction. Since the energy production rate is a linear function while
Interconnection of nitrogen fixers and iron in the Pacific Ocean: Theory and numerical simulations
Interconnection of nitrogen fixers and iron in the Pacific Ocean: Theory and numerical simulations, F. Monteiro, and M. J. Follows (2012), Interconnection of nitrogen fixers and iron in the Pacific interconnected. Microbial community structure is shaped by the variable physical, chemical and predatory
Raman, Sethu
-level pollutant dispersion. When an urban area is located at the coast of a large body of water, complexitiesObservations and Numerical Simulations of Urban Heat Island and Sea Breeze Circulations over New examined during several synoptic scale flow regimes over New York City after the World Trade Center
Numerical simulation of air/water multiphase flows for ceramic sanitary ware design by multiple GPUs
Furui, Sadaoki
and kitchen fittings. Facing the increasing demands for saving energy and water, TOTO has always targeted schemes and port the code to the GPU platforms to accelerate the large scale computations for real** Tokyo Institute of Technology, Department of energy sciences Numerical simulation of air
Numerical simulations of gas-particle flows with combustion Julien NUSSBAUM
Paris-Sud XI, UniversitÃ© de
Numerical simulations of gas-particle flows with combustion Julien NUSSBAUM French-german Research. At the initial time, the mixture of gas-powder grains is contained in the combustion chamber, limited gas species. The pressure increases in the combustion chamber, while the front flame propagates
Numerical methods for the simulation of a corrosion model in a nuclear waste deep repository $
Paris-Sud XI, UniversitÃ© 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
APPENDIX B -GRAPHICS Most computer simulation work produces lots of numerical data. The analysis of
Boal, David
APPENDIX B - GRAPHICS Most computer simulation work produces lots of numerical data. The analysis. In this section, we describe some elements of computer graphics that are appropriate to the Apple PowerPCs of the Computational Physics Lab. Further editions of these notes will include Windows versions of the graphics. Our
Numerical Simulation and Multiple Realizations for Sensitivity Study of Shale Gas Reservoir
Mohaghegh, Shahab
SPE 141058 Numerical Simulation and Multiple Realizations for Sensitivity Study of Shale Gas. The abstract must contain conspicuous acknowledgment of SPE copyright. Abstract Shale gas in the United States the largest conventional gas accumulations in the world. Shale gas success is directly the result
Maneuverability of ships in ice: numerical simulation and comparison with field measurements
Nørvåg, Kjetil
Maneuverability of ships in ice: numerical simulation and comparison with field measurements Biao Su Department of Marine Technology, NTNU May 28, 2013 #12;Motivation Local ice load Global ice load Ship's performance · Ice-hull interaction · Local ice load · Global ice load · Ship's performance #12
Numerical simulation of ice-induced loads on ships and comparison with field measurements
Nørvåg, Kjetil
Numerical simulation of ice-induced loads on ships and comparison with field measurements Biao Su Department of Marine Technology, NTNU May 28, 2013 #12;Motivation Local ice load Global ice load Ship's performance · Ice-hull interaction · Local ice load · Global ice load · Ship's performance #12;Outline
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 #12;Contents 1 Introduction 1 2 Model description 3 2.1 Basic Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3.2 Finite Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 3.2.1 Grid
Steam generators two phase flows numerical simulation with liquid and gas momentum equations
Paris-Sud XI, UniversitÃ© de
Steam 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 words: Steam Generator, Two-phase Flow, Finite element Email address: Marc.Grandotto@cea.fr (M
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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),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the ContributionsArms Control R&DNuclear fuel recycling in 4vs. Secondary9 0Numerical
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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker,(Biasi, Et
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.
Direct Numerical Simulations of Nonlinear Evolution of MHD Instability in LHD
Miura, H.; Nakajima, N.; Hayashi, T. [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Department of Fusion Science, The Graduate University for Advanced Studies (SOKENDAI), 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Okamoto, M. [Department of Information Science, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501 (Japan)
2006-11-30T23:59:59.000Z
Nonlinear evolutions of MHD instabilities in the large helical device are studied by means of direct numerical simulations under the vacuum configuration with the magnetic axis position R = 3.6m, including effects of its full three-dimensional geometry, flows parallel to the magnetic field lines and the fluid compressibility. The linear growth of the pressure-driven modes and their nonlinear saturations are observed. The linear growth brings about the flows parallel to the magnetic field lines as strong as the perpendicular flows. The fluid compressibility reduces the linear growth rate significantly. In the nonlinear saturation process, a qualitative difference is found in the behaviors of the parallel and perpendicular flows. The plasma appears to approach to a near-equilibrium state, keeping finite amplitudes of the parallel flow. Our numerical results highlight important roles of the parallel flow and compressibility in nonlinear MHD simulations in the large helical device.
Direct Numerical Simulations of the Kraichnan Model: Scaling Exponents and Fusion Rules
Adrienne L. Fairhall; Barak Galanti; Victor S. L'vov; Itamar Procaccia
1997-07-01T23:59:59.000Z
We present results from direct numerical simulations of the Kraichnan model for passive scalar advection by a rapidly-varying random scaling velocity field for intermediate values of the velocity scaling exponent. These results are compared with the scaling exponents predicted for this model by Kraichnan. Further, we test the recently proposed fusion rules which govern the scaling properties of multi-point correlations, and present results on the linearity of the conditional statistics of the Laplacian operator on the scalar field.
Numerical simulations of stripping effects in high-intensity hydrogen ion linacs
Carneiro, J.-P.; /Fermilab; Mustapha, B.; Ostroumov, P.N.; /Argonne
2008-12-01T23:59:59.000Z
Numerical simulations of H{sup -} stripping losses from blackbody radiation, electromagnetic fields, and residual gas have been implemented into the beam dynamics code TRACK. Estimates of the stripping losses along two high-intensity H{sup -} linacs are presented: the Spallation Neutron Source linac currently being operated at Oak Ridge National Laboratory and an 8 GeV superconducting linac currently being designed at Fermi National Accelerator Laboratory.
Johnsen, Eric [Center for Turbulence Research, Stanford University, Stanford, CA 94305 (United States)], E-mail: johnsen@stanford.edu; Larsson, Johan [Center for Turbulence Research, Stanford University, Stanford, CA 94305 (United States)], E-mail: jola@stanford.edu; Bhagatwala, Ankit V. [Department of Aeronautics and Astronautics, Stanford University, Stanford, CA 94305 (United States); Cabot, William H. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Moin, Parviz [Center for Turbulence Research, Stanford University, Stanford, CA 94305 (United States); Olson, Britton J. [Department of Aeronautics and Astronautics, Stanford University, Stanford, CA 94305 (United States); Rawat, Pradeep S. [Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, CA 90095 (United States); Shankar, Santhosh K. [Department of Aeronautics and Astronautics, Stanford University, Stanford, CA 94305 (United States); Sjoegreen, Bjoern [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Yee, H.C. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Zhong Xiaolin [Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, CA 90095 (United States); Lele, Sanjiva K. [Department of Aeronautics and Astronautics, Stanford University, Stanford, CA 94305 (United States)
2010-02-20T23:59:59.000Z
Flows in which shock waves and turbulence are present and interact dynamically occur in a wide range of applications, including inertial confinement fusion, supernovae explosion, and scramjet propulsion. Accurate simulations of such problems are challenging because of the contradictory requirements of numerical methods used to simulate turbulence, which must minimize any numerical dissipation that would otherwise overwhelm the small scales, and shock-capturing schemes, which introduce numerical dissipation to stabilize the solution. The objective of the present work is to evaluate the performance of several numerical methods capable of simultaneously handling turbulence and shock waves. A comprehensive range of high-resolution methods (WENO, hybrid WENO/central difference, artificial diffusivity, adaptive characteristic-based filter, and shock fitting) and suite of test cases (Taylor-Green vortex, Shu-Osher problem, shock-vorticity/entropy wave interaction, Noh problem, compressible isotropic turbulence) relevant to problems with shocks and turbulence are considered. The results indicate that the WENO methods provide sharp shock profiles, but overwhelm the physical dissipation. The hybrid method is minimally dissipative and leads to sharp shocks and well-resolved broadband turbulence, but relies on an appropriate shock sensor. Artificial diffusivity methods in which the artificial bulk viscosity is based on the magnitude of the strain-rate tensor resolve vortical structures well but damp dilatational modes in compressible turbulence; dilatation-based artificial bulk viscosity methods significantly improve this behavior. For well-defined shocks, the shock fitting approach yields good results.
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.
Paik, Joongcheol [University of Minnesota; Sotiropoulos, Fotis [University of Minnesota; Sale, Michael J [ORNL
2005-06-01T23:59:59.000Z
A numerical method is developed for carrying out unsteady Reynolds-averaged Navier-Stokes (URANS) simulations and detached-eddy simulations (DESs) in complex 3D geometries. The method is applied to simulate incompressible swirling flow in a typical hydroturbine draft tube, which consists of a strongly curved 90 degree elbow and two piers. The governing equations are solved with a second-order-accurate, finite-volume, dual-time-stepping artificial compressibility approach for a Reynolds number of 1.1 million on a mesh with 1.8 million nodes. The geometrical complexities of the draft tube are handled using domain decomposition with overset (chimera) grids. Numerical simulations show that unsteady statistical turbulence models can capture very complex 3D flow phenomena dominated by geometry-induced, large-scale instabilities and unsteady coherent structures such as the onset of vortex breakdown and the formation of the unsteady rope vortex downstream of the turbine runner. Both URANS and DES appear to yield the general shape and magnitude of mean velocity profiles in reasonable agreement with measurements. Significant discrepancies among the DES and URANS predictions of the turbulence statistics are also observed in the straight downstream diffuser.
Numerical simulation of discharge structures in Ar/Cs nonequilibrium plasma MHD generator
Okubo, M.; Kabashima, S.; Okuno, Y.; Yamasaki, H.
1998-07-01T23:59:59.000Z
As reported in previous papers, the quasi-one-dimensional simulation code has come to predict almost satisfactorily the performance of the shock tube driven disk MHD generator using cesium seeded argon plasma as working fluid. However, the agreement between experimental and predicted performances was not so good on the conditions that the external load resistance was small, the seed fraction was high or the stagnation pressure was low. On these conditions, it was observed that ionization instabilities occur in the MHD channel. On the other hand, high-speed photographs of the nonequilibrium plasma discharge in the MHD generator were taken on several working conditions during the experiment. From these photographs, discharges were classified into almost three kinds of patterns. (a) A single strong luminous ring-type discharge near the nozzle exit for low seed fraction, (b) an almost uniform discharge inside the MHD channel for medium seed fraction, (c) multiple ring-type or spiral discharges in the MHD channel for high seed fraction. The structures of the discharge were sometimes two-dimensional especially for high seed fraction. Therefore, it may be impossible in this case to simulate them and to predict the performance precisely with one-dimensional simulation code. In the present study, two-dimensional (r-q) numerical simulations were made on the disk MHD power generation experiment (thermal input is about 1.5MW). The objectives were to develop a numerical simulator with high accuracy for the disk MHD generator and to explain some interesting phenomena concerned with nonequilibrium plasma discharges. The system of basic equations was solved mainly using CIP method. The calculation region was taken as that located between the throat to the inlet of the second (final) cathode. The main results are summarized as follows; (A) On the condition that the seed fraction was lower than the optimum value, it was succeeded to simulate numerically the single strong luminous ring-type discharge. The ring-type discharge was caused by the partial ionization of argon due to the rapid increase in the electron temperature in the nozzle. The pressure increase like a shock wave was also induced there. (B) On the condition that the seed fraction was near the optimum value, an almost uniform plasma was obtained in the simulation and in the experiment. (C) On the condition that seed fraction was higher than the optimum value, A similar structure of discharge to experimental one was obtained in the calculation due to an ionization instability (streamer) caused by the partial ionization of seeded cesium. (D) The performances of the generator such as enthalpy extraction can be predicted well with this simulation code.
Conway, A; Wang, T; Deo, N; Cheung, C; Nikolic, R
2008-06-24T23:59:59.000Z
This work reports numerical simulations of a novel three-dimensionally integrated, {sup 10}boron ({sup 10}B) and silicon p+, intrinsic, n+ (PIN) diode micropillar array for thermal neutron detection. The inter-digitated device structure has a high probability of interaction between the Si PIN pillars and the charged particles (alpha and {sup 7}Li) created from the neutron - {sup 10}B reaction. In this work, the effect of both the 3-D geometry (including pillar diameter, separation and height) and energy loss mechanisms are investigated via simulations to predict the neutron detection efficiency and gamma discrimination of this structure. The simulation results are demonstrated to compare well with the measurement results. This indicates that upon scaling the pillar height, a high efficiency thermal neutron detector is possible.
Some effects of data base variations on numerical simulations of uranium migration
Carnahan, C.L.
1987-12-01T23:59:59.000Z
Numerical simulations of migration of chemicals in the geosphere depend on knowledge of identities of chemical species and on values of chemical equilibrium constants supplied to the simulators. In this work, some effects of variability in assumed speciation and in equilibrium constants were examined, using migration of uranium as an example. Various simulations were done of uranium migration in systems with varying oxidation potential, pH, and mator component content. A simulation including formation of aqueous species UO/sub 2//sup 2 +/, UO/sub 2/CO/sub 3//sup 0/, UO/sub 2/(CO/sub 3/)/sub 2//sup 2 -/, UO/sub 2/(CO/sub 3/)/sub 3//sup 4 -/, (UO/sub 2/)/sub 2/CO/sub 3/(OH)/sub 3//sup -/, UO/sub 2//sup +/, U(OH)/sub 4//sup 0/, and U(OH)/sub 5//sup -/ is compared to simulation excluding formation of UO/sub 2//sup +/ and U(OH)/sub 5//sup -/. These simulations relied on older data bases, and they are compared to a further simulation using recently published data on formation of U(OH)/sub 4//sup 0/, (UO/sub 2/)/sub 2/CO/sub 3/(OH)/sub 3//sup -/, UO/sub 2/(CO/sub 3/)/sub 5//sup 5 -/, and U(CO/sub 3/)/sub 5//sup 6 -/. Significant differences in dissolved uranium concentrations are noted among the simulations. Differences are noted also in precipitation of two solids, USiO/sub 4/(c) (coffinite) and CaUO/sub 4/(c) (calcium uranate), although the solubility products of the solids were not varied in the simulations. 18 refs., 9 figs., 2 tabs.
V.K. Dhir
2003-04-28T23:59:59.000Z
At present, guidelines for fuel cycle designs to prevent axial offset anomalies (AOA) in pressurized water reactor (PWR) cores are based on empirical data from several operating reactors. Although the guidelines provide an ad-hoc solution to the problem, a unified approach based on simultaneous modeling of thermal-hydraulics, chemical, and nuclear interactions with vapor generation at the fuel cladding surface does not exist. As a result, the fuel designs are overly constrained with a resulting economic penalty. The objective of present project is to develop a numerical simulation model supported by laboratory experiments that can be used for fuel cycle design with respect to thermal duty of the fuel to avoid economic penalty, as well as, AOA. At first, two-dimensional numerical simulation of the growth and departure of a bubble in pool boiling with chemical interaction is considered. A finite difference scheme is used to solve the equations governing conservation of mass, momentum, energy, and species concentration. The Level Set method is used to capture the evolving liquid-vapor interface. A dilute aqueous boron solution is considered in the simulation. From numerical simulations, the dynamic change in concentration distribution of boron during the bubble growth shows that the precipitation of boron can occur near the advancing and receding liquid-vapor interface when the ambient boron concentration level is 3,000 ppm by weight. Secondly, a complete three-dimensional numerical simulation of inception, growth and departure of a single bubble subjected to forced flow parallel to the heater surface was developed. Experiments on a flat plate heater with water and with boron dissolved in the water were carried out. The heater was made out of well-polished silicon wafer. Numbers of nucleation sites and their locations were well controlled. Bubble dynamics in great details on an isolated nucleation site were obtained while varying the wall superheat, liquid subcooling and flow velocity parametrically. Concentration variation of boron near the liquid-vapor interface was detected successfully with a newly developed miniature concentration sensor. The measured concentration variations at different radial locations from the center of cavity have the same trend as given by the numerical simulations. The deposition of boron was found near the nucleation site on the heater surface, which validates the numerical simulation. Subcooled flow boiling experiments at three pressures were performed on a nine-rod bundle with water and with boron dissolved in the water. The test runs were conducted with a wide range of mass fluxes (186 to 2800 kg/m2s) and heat fluxes (1.0 to 30.0 W/ cm2). Not only the variables required to develop mechanistic models for subcooled flow boiling were measured, but also the crud formation during boiling and its effect on the heat transfer process were investigated. (B204)
MAGNETOACOUSTIC WAVE ENERGY FROM NUMERICAL SIMULATIONS OF AN OBSERVED SUNSPOT UMBRA
Felipe, T.; Khomenko, E.; Collados, M., E-mail: tobias@iac.es [Instituto de Astrofisica de Canarias, 38205, C/Via Lactea, s/n, La Laguna, Tenerife (Spain)
2011-07-01T23:59:59.000Z
We aim at reproducing the height dependence of sunspot wave signatures obtained from spectropolarimetric observations through three-dimensional MHD numerical simulations. A magnetostatic sunspot model based on the properties of the observed sunspot is constructed and perturbed at the photosphere, introducing the fluctuations measured with the Si I {lambda}10827 line. The results of the simulations are compared with the oscillations observed simultaneously at different heights from the He I {lambda}10830 line, the Ca II H core, and the Fe I blends in the wings of the Ca II H line. The simulations show a remarkable agreement with the observations. They reproduce the velocity maps and power spectra at the formation heights of the observed lines, as well as the phase and amplification spectra between several pairs of lines. We find that the stronger shocks at the chromosphere are accompanied with a delay between the observed signal and the simulated one at the corresponding height, indicating that shocks shift the formation height of the chromospheric lines to higher layers. Since the simulated wave propagation matches very well the properties of the observed one, we are able to use the numerical calculations to quantify the energy contribution of the magnetoacoustic waves to the chromospheric heating in sunspots. Our findings indicate that the energy supplied by these waves is too low to balance the chromospheric radiative losses. The energy contained at the formation height of the lowermost Si I {lambda}10827 line in the form of slow magnetoacoustic waves is already insufficient to heat the higher layers, and the acoustic energy which reaches the chromosphere is around 3-9 times lower than the required amount of energy. The contribution of the magnetic energy is even lower.
Ruban, V P
2015-01-01T23:59:59.000Z
The nonlinear dynamics of an obliquely oriented wave packet at sea surface is studied both analytically and numerically for various initial parameters of the packet, in connection with the problem of oceanic rogue waves. In the framework of Gaussian variational ansatz applied to the corresponding (1+2D) hyperbolic nonlinear Schr\\"odinger equation, a simplified Lagrangian system of differential equations is derived, which determines the evolution of coefficients of the real and imaginary quadratic forms appearing in the Gaussian. This model provides a semi-quantitative description for the process of nonlinear spatio-temporal focusing, which is one of the most probable mechanisms of rogue wave formation in random wave fields. The system is integrated in quadratures, which fact allows us to understand qualitative differences between the linear and nonlinear regimes of the focusing of wave packet. Comparison of the Gaussian model predictions with results of direct numerical simulation of fully nonlinear long-cres...
THE REBOUND CONDITION OF DUST AGGREGATES REVEALED BY NUMERICAL SIMULATION OF THEIR COLLISIONS
Wada, Koji [Planetary Exploration Research Center, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016 (Japan); Tanaka, Hidekazu; Yamamoto, Tetsuo [Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819 (Japan); Suyama, Toru [Nagano City Museum, Hachimanpara Historic Park, Oshimada, Nagano 381-2212 (Japan); Kimura, Hiroshi, E-mail: wada@perc.it-chiba.ac.jp [Center for Planetary Science (CPS), Chuo-ku Minatojima Minamimachi 7-1-48, Kobe 650-0047 (Japan)
2011-08-10T23:59:59.000Z
Collisional growth of dust aggregates is a plausible root of planetesimals forming in protoplanetary disks. However, a rebound of colliding dust aggregates prevents dust from growing into planetesimals. In fact, rebounding aggregates are observed in laboratory experiments but not in previous numerical simulations. Therefore, the condition of rebound between dust aggregates should be clarified to better understand the processes of dust growth and planetesimal formation. We have carried out numerical simulations of aggregate collisions for various types of aggregates and succeeded in reproducing a rebound of colliding aggregates under specific conditions. Our finding is that in the rebound process, the key factor of the aggregate structure is the coordination number, namely, the number of particles in contact with a particle. A rebound is governed by the energy dissipation along with restructuring of the aggregates and a large coordination number inhibits the restructuring at collisions. Results of our numerical simulation for various aggregates indicate that they stick to each other when the mean coordination number is less than 6, regardless of their materials and structures, as long as their collision velocity is less than the critical velocity for fragmentation. This criterion of the coordination number would correspond to a filling factor of {approx}0.3, which is somewhat larger than that reported in laboratory experiments. In protoplanetary disks, dust aggregates are expected to have low bulk densities (<0.1 g cm{sup -3}) during their growth, which would prevent dust aggregates from rebounding. This result supports the formation of planetesimals with direct dust growth in protoplanetary disks.
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.
Sokolov, A. S. [JSC 'B. E. Vedeneev All-Russia Research Institute of Hydraulic Engineering (VNIIG)' (Russian Federation)] [JSC 'B. E. Vedeneev All-Russia Research Institute of Hydraulic Engineering (VNIIG)' (Russian Federation)
2013-07-15T23:59:59.000Z
Consideration is given to the numerical simulation of the thermal conditions in sea water areas used for both water supply to and dissipation of low-grade heat from a nuclear power plant on the shore of a sea bay.
Kaul, Sandeep P.
2004-09-30T23:59:59.000Z
Spontaneous imbibition plays a very important role in the displacement mechanism of non-wetting fluid in naturally fractured reservoirs. We developed a new 2D two-phase finite element numerical model, as available commercial simulators cannot...
Bell, John B.
Multidimensional Numerical Simulation of a Pulse Combustor \\Lambda Daniel L. Marcus, Richard B combustors. Our approach is based on the use of higherorder Godunov methods combined with adaptive
Using Numerical Simulations to Gain Insight into the Structure of Superbubbles
Philip T. Komljenovic; Shantanu Basu; Doug Johnstone
1999-01-21T23:59:59.000Z
Recent high resolution observations of Galactic superbubbles have motivated us to re-examine several classes of superbubble models. We compare three classes of hydrodynamic models (the Kompaneets approximation, the thin shell model, and numerical simulations) in order to understand the structure of superbubbles and to gain insight into observations. In particular, we apply models to the W4 superbubble, which has been observed in the Pilot project of the arcminute resolution Canadian Galactic Plane Survey (Normandeau et al. 1996). Magnetohydrodynamic simulations are also performed and point the way to a fuller understanding of the W4 superbubble. We suggest that the highly collimated bubble and apparent lack of a Rayleigh-Taylor instability in the superbubble shell can be explained by the presence of a magnetic field.
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...
Magneto-acoustic wave energy from numerical simulations of an observed sunspot umbra
Felipe, T; Collados, M
2011-01-01T23:59:59.000Z
We aim at reproducing the height dependence of sunspot wave signatures obtained from spectropolarimetric observations through 3D MHD numerical simulations. A magneto-static sunspot model based on the properties of the observed sunspot is constructed and perturbed at the photosphere introducing the fluctuations measured with the \\SiI\\ $\\lambda$ 10827 \\AA\\ line. The results of the simulations are compared with the oscillations observed simultaneously at different heights from the \\HeI\\ $\\lambda$ 10830 \\AA\\ line, the \\CaIIH\\ core and the \\FeI\\ blends in the wings of the \\CaIIH\\ line. The simulations show a remarkable agreement with the observations. They reproduce the velocity maps and power spectra at the formation heights of the observed lines, as well as the phase and amplification spectra between several pair of lines. We find that the stronger shocks at the chromosphere are accompanied with a delay between the observed signal and the simulated one at the corresponding height, indicating that shocks shift th...
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.
Direct numerical simulation of electrokinetic instability and transition to chaotic motion
Demekhin, E. A., E-mail: edemekhi@gmail.com [Laboratory of Micro- and Nanofluidics, Moscow State University, Moscow 119192 (Russian Federation); Department of Computation Mathematics and Computer Science, Kuban State University, Krasnodar 350040 (Russian Federation); Institute of Mechanics, Moscow State University, Moscow 117192 (Russian Federation); Nikitin, N. V. [Institute of Mechanics, Moscow State University, Moscow 117192 (Russian Federation)] [Institute of Mechanics, Moscow State University, Moscow 117192 (Russian Federation); Shelistov, V. S. [Institute of Mechanics, Moscow State University, Moscow 117192 (Russian Federation) [Institute of Mechanics, Moscow State University, Moscow 117192 (Russian Federation); Scientific Research Department, Kuban State University, Krasnodar 350040 (Russian Federation)
2013-12-15T23:59:59.000Z
A new type of instability—electrokinetic instability—and an unusual transition to chaotic motion near a charge-selective surface (semiselective electric membrane, electrode, or system of micro-/nanochannels) was studied by the numerical integration of the Nernst-Planck-Poisson-Stokes system and a weakly nonlinear analysis near the threshold of instability. A special finite-difference method was used for the space discretization along with a semi-implicit 31/3 -step Runge-Kutta scheme for the integration in time. Two kinds of initial conditions were considered: (a) white-noise initial conditions to mimic “room disturbances” and subsequent natural evolution of the solution, and (b) an artificial monochromatic ion distribution with a fixed wave number to simulate regular wave patterns. The results were studied from the viewpoint of hydrodynamic stability and bifurcation theory. The threshold of electroconvective movement was found by the linear spectral stability theory, the results of which were confirmed by numerical simulation of the entire system. Our weakly nonlinear analysis and numerical integration of the entire system predict possibility of both kinds of bifurcations at the critical point, supercritical and subcritical, depending on the system parameters. The following regimes, which replace each other as the potential drop between the selective surfaces increases, were obtained: one-dimensional steady solution, two-dimensional steady electroconvective vortices (stationary point in a proper phase space), unsteady vortices aperiodically changing their parameters (homoclinic contour), periodic motion (limit cycle), and chaotic motion. The transition to chaotic motion does not include Hopf bifurcation. The numerical resolution of the thin concentration polarization layer showed spike-like charge profiles along the surface, which could be, depending on the regime, either steady or aperiodically coalescent. The numerical investigation confirmed the experimentally observed absence of regular (near-sinusoidal) oscillations for the overlimiting regimes. There is a qualitative agreement of the experimental and the theoretical values of the threshold of instability, the dominant size of the observed coherent structures, and the experimental and theoretical volt–current characteristics.
Claudin, Philippe
simulation of turbulent sediment transport O. DurÃ¡n (1,2) , B. Andreotti (1) , P. Claudin (1) 1. Laboratoire Carolina 27515, USA Abstract Sediment transport is studied by means of two phase numerical simulations to empirical transport laws. The vertical velocities of the grains are small and sediment transport occurs
Torres-VerdÃn, 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
Interpreting Velocities from Heat-Based Flow Sensors by NumericalSimulation
Su, Grace W.; Freifeld, Barry M.; Oldenburg, Curtis M.; Jordan,Preston D.; Daley, Paul F.
2005-06-13T23:59:59.000Z
We have carried out numerical simulations of three-dimensional non-isothermal flow around an in situ heat-based flow sensor to investigate how formation heterogeneities can affect the interpretation of ground water flow velocities from this instrument. The flow sensor operates by constant heating of a 0.75 m long, 5 cm diameter cylindrical probe, which contains 30 thermistors in contact with the formation. The temperature evolution at each thermistor can be inverted to obtain an estimate of the ground water flow velocity vector using the standard interpretive method, which assumes that the formation is homogeneous. Analysis of data from heat-based flow sensors installed in a sand aquifer at the Former Fort Ord Army Base near Monterey, California suggested an unexpected component of downward flow. The magnitudes of the vertical velocities were expected to be much less than the horizontal velocities at this site because the sensors were installed just above a clay aquitard. Numerical simulations were conducted to examine how differences in thermal conductivities may lead to spurious indications of vertical flow velocities. We found that a decrease in the thermal conductivity near the bottom of the sensor can perturb the temperature profiles along the instrument in such a manner that analyses assuming homogeneous thermal conductivity could indicate a vertical flow component even though flow is actually horizontal. This work demonstrates how modeling can be used to simulate instrument response to formation heterogeneity, and shows that caution must be used in interpreting data from such devices using overly simplistic assumptions.
Numerical simulation of narrow bipolar electromagnetic pulses generated by thunderstorm discharges
Bochkov, E. I.; Babich, L. P., E-mail: babich@elph.vniief.ru; Kutsyk, I. M. [All-Russia Research Institute of Experimental Physics, Russian Federal Nuclear Center (Russian Federation)] [All-Russia Research Institute of Experimental Physics, Russian Federal Nuclear Center (Russian Federation)
2013-07-15T23:59:59.000Z
Using the concept of avalanche relativistic runaway electrons (REs), we perform numerical simulations of compact intracloud discharge (CID) as a generator of powerful natural electromagnetic pulses (EMPs) in the HF-VHF range, called narrow bipolar pulses (NBPs). For several values of the field overvoltage and altitude at which the discharge develops, the numbers of seed electrons initiating the avalanche are evaluated, with which the calculated EMP characteristics are consistent with the measured NBP parameters. We note shortcomings in the hypothesis assuming participation of cosmic ray air showers in avalanche initiation. The discharge capable of generating NBPs produces REs in numbers close to those in the source of terrestrial {gamma}-ray flashes (TGFs), which can be an argument in favor of a unified NBP and TGF source.
TOUGH2: A general-purpose numerical simulator for multiphase fluid and heat flow
Pruess, K.
1991-05-01T23:59:59.000Z
TOUGH2 is a numerical simulation program for nonisothermal flows of multicomponent, multiphase fluids in porous and fractured media. The chief applications for which TOUGH2 is designed are in geothermal reservoir engineering, nuclear waste disposal, and unsaturated zone hydrology. A successor to the TOUGH program, TOUGH2 offers added capabilities and user features, including the flexibility to handle different fluid mixtures, facilities for processing of geometric data (computational grids), and an internal version control system to ensure referenceability of code applications. This report includes a detailed description of governing equations, program architecture, and user features. Enhancements in data inputs relative to TOUGH are described, and a number of sample problems are given to illustrate code applications. 46 refs., 29 figs., 12 tabs.
Numerical simulations in support of the in situ bioremediation demonstration at Savannah River
Travis, B.J.; Rosenberg, N.D.
1994-06-01T23:59:59.000Z
This report assesses the performance of the in situ bioremediation technology demonstrated at the Savannah River Integrated Demonstration (SRID) site in 1992--1993. The goal of the technology demonstration was to stimulate naturally occurring methanotrophic bacteria at the SRID site with injection of methane, air and air-phase nutrients (nitrogen and phosphate) such that significant amounts of the chlorinated solvent present in the subsurface would be degraded. Our approach is based on site-specific numerical simulations using the TRAMP computer code. In this report, we discuss the interactions among the physical and biochemical processes involved in in situ bioremediation. We also investigate improvements to technology performance, make predictions regarding the performance of this technology over long periods of time and at different sites, and compare in situ bioremediation with other remediation technologies.
Dingle, A.N.
1982-05-12T23:59:59.000Z
A numerical model designed for the study of mesoscale weather phenomena is presented. It is a three-dimensional, time-dependent model based upon a mesoscale primitive-equation system, and it includes parameterizations of cloud and precipitation processes, boundary-layer transfers, and ground surface energy and moisture budgets. This model was used to simulate the lake-effect convergence over and in the lee of Lake Michigan in late fall and early winter. The lake-effect convergence is created in advected cold air as it moves first from cold land to the warm constant-temperature lake surface, and then on to cold land. A numerical experiment with a prevailing northwesterly wind is conducted for a period of twelve hours. Two local maxima of the total precipitation are observed along the eastern shore of Lake Michigan. The results in this hypothetical case correspond quite well to the observed precipitation produced by a real event in which the hypothetical conditions are approximately fulfilled.
A Review of Direct Numerical Simulations of Astrophysical Detonations and Their Implications
Parete-Koon, Suzanne T [ORNL; Messer, Bronson [ORNL; Smith, Chris R [ORNL; Papatheodore, Thomas L [ORNL
2013-01-01T23:59:59.000Z
Multi-dimensional direct numerical simulations (DNS) of astrophysical detonations in degenerate matter have revealed that the nuclear burning is typically characterized by cellular structure caused by transverse instabilities in the detonation front. Type Ia supernova modelers often use one- dimensional DNS of detonations as inputs or constraints for their whole star simulations. While these one-dimensional studies are useful tools, the true nature of the detonation is multi-dimensional. The multi-dimensional structure of the burning influences the speed, stability, and the composition of the detonation and its burning products, and therefore, could have an impact on the spectra of Type Ia supernovae. Considerable effort has been expended modeling Type Ia supernovae at densities above 1 107 g cm 3 where the complexities of turbulent burning dominate the flame propagation. However, most full star models turn the nuclear burning schemes off when the density falls below 1 107 g cm 3 and distributed burning begins. The deflagration to detonation transition (DDT) is believed to occur at just these densities and consequently they are the densities important for studying the properties of the subsequent detonation. This work will review the status of DNS studies of detonations and their possible implications for Type Ia supernova models. It will cover the development of Detonation theory from the first simple Chapman-Jouguet (CJ) detonation models to the current models based on the time-dependent, compressible, reactive flow Euler equations of fluid dynamics.
Kerley, Gerald I
2013-01-01T23:59:59.000Z
This report presents new EOS and strength models for use in numerical hydrocode simulations of dust impacts on the NASA solar probe space vehicle. This spacecraft will be subjected to impact at velocities up to 300 km/s, producing pressures as high as 100 TPa and temperatures as high as 200 eV. Hence the material models must treat a variety of physical and chemical phenomena, including solid-solid transitions, melting and vaporization, chemical reactions, electronic excitation and ionization. The EOSPro code is used to develop tabular EOS that include these effects. The report discusses the theoretical methods used to create the new EOS tables and constitutive models for six materials--Al2O3, two porous carbon materials, fused SiO2, a silicone elastomer, and germanium--which will be used in the thermal protection shield (TPS) and solar cells, the components most vulnerable to dust impacts. It also presents the results of hydrocode simulations of dust impacts on the TPS and on glass targets. It discusses the i...
Numerical simulation of shock initiation of Ni/Al multilayered composites
Sraj, Ihab; Knio, Omar M., E-mail: omar.knio@duke.edu [Department of Mechanical Engineering and Materials Science, Duke University, 144 Hudson Hall, Durham, North Carolina 27708 (United States); Specht, Paul E.; Thadhani, Naresh N. [School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, Georgia 30332 (United States); Weihs, Timothy P. [Department of Materials Science and Engineering, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218 (United States)
2014-01-14T23:59:59.000Z
The initiation of chemical reaction in cold-rolled Ni/Al multilayered composites by shock compression is investigated numerically. A simplified approach is adopted that exploits the disparity between the reaction and shock loading timescales. The impact of shock compression is modeled using CTH simulations that yield pressure, strain, and temperature distributions within the composites due to the shock propagation. The resulting temperature distribution is then used as initial condition to simulate the evolution of the subsequent shock-induced mixing and chemical reaction. To this end, a reduced reaction model is used that expresses the local atomic mixing and heat release rates in terms of an evolution equation for a dimensionless time scale reflecting the age of the mixed layer. The computations are used to assess the effect of bilayer thickness on the reaction, as well as the impact of shock velocity and orientation with respect to the layering. Computed results indicate that initiation and evolution of the reaction are substantially affected by both the shock velocity and the bilayer thickness. In particular, at low impact velocity, Ni/Al multilayered composites with thick bilayers react completely in 100?ms while at high impact velocity and thin bilayers, reaction time was less than 100??s. Quantitative trends for the dependence of the reaction time on the shock velocity are also determined, for different bilayer thickness and shock orientation.
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 simulations of quiet Sun magnetism: On the contribution from a small-scale dynamo
Rempel, M
2014-01-01T23:59:59.000Z
We present a series of radiative MHD simulations addressing the origin and distribution of mixed polarity magnetic field in the solar photosphere. To this end we consider numerical simulations that cover the uppermost 2-6 Mm of the solar convection zone and we explore scales ranging from 2 km to 25 Mm. We study how the strength and distribution of magnetic field in the photosphere and subsurface layers depend on resolution, domain size and boundary conditions. We find that 50% of the magnetic energy at the \\tau=1 level comes from field with the less than 500 G strength and that 50% of the energy resides on scales smaller than about 100 km. While probability distribution functions are essentially independent of resolution, properly describing the spectral energy distribution requires grid spacings of 8 km or smaller. The formation of flux concentrations in the photosphere exceeding 1 kG requires a mean vertical field strength greater than 30-40 G at \\tau=1. The filling factor of kG flux concentrations increase...
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.
Laprea-Bigott, Marcelo
1976-01-01T23:59:59.000Z
in performance. Also, under these conditions, the calculated results are highly sen- sitive to grid orientation. '1 * Todd, et al. demonstrated the grid orientation effects for five-point finite difference reservoir simulators. They proposed a two... GRAPHICAL DESCRIPTION numerical dispersion and grid orientation effects. The difference in recovery performance for diagonal and parallel grids was not ap- preciable when finer grids were used, Coats, et al. simulated a five-spot steamflood...
Numerical simulations of aggregate breakup in bounded and unbounded turbulent flows
Matthaus U. Babler; Luca Biferale; Luca Brandt; Ulrike Feudel; Ksenia Guseva; Alessandra S. Lanotte; Cristian Marchioli; Francesco Picano; Gaetano Sardina; Alfredo Soldati; Federico Toschi
2015-02-17T23:59:59.000Z
Breakup of small aggregates in fully developed turbulence is studied by means of direct numerical simulations in a series of typical bounded and unbounded flow configurations, such as a turbulent channel flow, a developing boundary layer and homogeneous isotropic turbulence. The simplest criterion for breakup is adopted, whereas aggregate breakup occurs when the local hydrodynamic stress $\\sigma\\sim \\varepsilon^{1/2}$, with $\\varepsilon$ being the energy dissipation at the position of the aggregate, overcomes a given threshold $\\sigma_\\mathrm{cr}$, which is characteristic for a given type of aggregates. Results show that the breakup rate decreases with increasing threshold. For small thresholds, it develops a universal scaling among the different flows. For high thresholds, the breakup rates show strong differences between the different flow configurations, highlighting the importance of non-universal mean-flow properties. To further assess the effects of flow inhomogeneity and turbulent fluctuations, theresults are compared with those obtained in a smooth stochastic flow. Furthermore, we discuss the limitations and applicability of a set of independent proxies.
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.
2003-11-24T23:59:59.000Z
Planar flames are intrinsically unstable in open domains due to the thermal expansion across the burning front--the Landau-Darrieus instability. This instability leads to wrinkling and growth of the flame surface, and corresponding acceleration of the flame, until it is stabilized by cusp formation. We look at the Landau-Darrieus in stability for C/O thermonuclear flames at conditions relevant to the late stages of a Type Ia supernova explosion. Two-dimensional direct numerical simulations of both single-mode and multi-mode perturbations using a low Mach number hydrodynamics code are presented. We show the effect of the instability on the flame speed as a function of both the density and domain size, demonstrate the existence of the small scale cutoff to the growth of the instability, and look for the proposed breakdown of the non-linear stabilization at low densities. The effects of curvature on the flame as quantified through measurements of the growth rate and computation of the corresponding Markstein number. While accelerations of a few percent are observed, they are too small to have any direct outcome on the supernova explosion.
Mahalingam, S. [Univ. of Colorado, Boulder, CO (United States). Center for Combustion Research] [Univ. of Colorado, Boulder, CO (United States). Center for Combustion Research; Chen, J.H. [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility] [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility; Vervisch, L. [CORIA, Rouen (France). Laboratoire de Mechanique des Fluides Numeriques] [CORIA, Rouen (France). Laboratoire de Mechanique des Fluides Numeriques
1995-08-01T23:59:59.000Z
Three-dimensional direct numerical simulations (DNS) of turbulent nonpremixed flames including finite-rate chemistry and heat release effects were performed. Two chemical reaction models were considered: (1) a single-step global reaction model in which the heat release and activation energy parameters are typical combustion applications, and (2) a two-step reaction model to stimulate radical production and consumption and to compare against the single-step model. The model problem consists of the interaction between an initially unstained laminar diffusion flame and a three-dimensional field of homogeneous turbulence. Conditions ranging from fast chemistry to the pure mixing limit were studied by varying a global Damkoehler number. Results suggest that turbulence-induced mixing acting along the stoichiometric line leads to a strong modification of the inner structure of the turbulent flame compared with a laminar strained flame, resulting in intermediate species concentrations well above the laminar prediction. This result is consistent the experimental observations. Comparison of the response of the turbulent flame structure due to changes in the scalar dissipation rate with a steady strained laminar flame reveals that unsteady strain rates experienced by the turbulent flame may be responsible for h3e observed high concentrations of reaction intermediates.
Annealing of ion irradiated high T{sub C} Josephson junctions studied by numerical simulations
Sirena, M.; Matzen, S.; Bergeal, N.; Lesueur, J. [LPEM-CNRS, Physique Quantique, ESPCI, 10 Rue Vauquelin, 75231 Paris (France); Faini, G. [LPN-CNRS, Route de Nozay, 91460 Marcoussis (France); Bernard, R.; Briatico, J.; Crete, D. G. [UMR-CNRS/THALES, Route D128, 91767 Palaiseau (France)
2009-01-15T23:59:59.000Z
Recently, annealing of ion irradiated high T{sub c} Josephson iunctions (JJs) has been studied experimentally in the perspective of improving their reproducibility. Here we present numerical simulations based on random walk and Monte Carlo calculations of the evolution of JJ characteristics such as the transition temperature T{sub c}{sup '} and its spread {delta}T{sub c}{sup '}, and compare them with experimental results on junctions irradiated with 100 and 150 keV oxygen ions, and annealed at low temperatures (below 80 deg. C). We have successfully used a vacancy-interstitial annihilation mechanism to describe the evolution of the T{sub c}{sup '} and the homogeneity of a JJ array, analyzing the evolution of the defects density mean value and its distribution width. The annealing first increases the spread in T{sub c}{sup '} for short annealing times due to the stochastic nature of the process, but then tends to reduce it for longer times, which is interesting for technological applications.
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.
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.
Sminchisescu, Cristian
Numerical simulation of bubble and droplet deformation by a level set approach with surface tension-dimensional NavierÂStokes solver for incompressible two-phase flow problems with surface tension and apply is the impact of surface tension and its discretization on the overall convergence behavior and conservation
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. TrÂ´elat Continuation from a flat to a round Earth model
Gardner, Carl
392 IEEE TRANSACTIONS ON ELECTRON DEVICES. VOL. 38. NO. 2. FEBRUARY 1991 Numerical Simulation of a Steady-State Electron Shock Wave in a Submicrometer Semiconductor Device Carl L. Gardner Abstract-state electron shock wave in a semicon- ductor device are presented, using the hydrodynamic model
Torres-VerdÃn, Carlos
and for the improvement of acoustic logging techniques used by oil- and oil-service companies to detect and quantifyNumerical simulation of borehole acoustic logging in the frequency and time domains with hp Available online 8 January 2009 Keywords: Acoustic logging Borehole acoustics Wave propagation Linear
PolitÃ¨cnica de Catalunya, Universitat
of the thermal outflow of some power plants in the Huelva estuary was studied. The outline of the paper developed are presented: the dispersion of the plume of the Ebro river and the thermal outflow of powerNumerical simulation of the dispersion of contaminants by a characteristic-based method
Pu, Zhaoxia
-surface atmospheric conditions are very important in many applications such as wind energy, agriculture, aviationExamination of Errors in Near-Surface Temperature and Wind from WRF Numerical Simulations of Utah, Salt Lake City, Utah XUEBO ZHANG Computational Engineering and Science, University of Utah, Salt
Mohaghegh, Shahab
injection into saline aquifer, CO2-EOR, CO2-ECBM, and so forth, have been studied to minimize the CO22-EOR, CO2-ECBM, and so forth, have been studied to minimize the CO2 release into the atmosphere1 CO2-Driven Enhanced Gas Recovery and Storage in Depleted Shale Reservoir- A Numerical Simulation
LBNL-49331 Numerical Simulation of Premixed Turbulent Methane Combustion John B. Bell, Marcus S of Premixed Turbulent Methane Combustion Abstract In this paper we study the behavior of a premixed turbulent an adaptive time-dependent low Mach number combustion algorithm based on a second-order projection formulation
Ng, Chung-Sang
ABSTRACT FINAL ID: SH51A-1991 TITLE: Three-Dimensional Numerical Simulations of Interaction Between, United States. Title of Team: ABSTRACT BODY: We have recently identified in three-dimensional (3D implications in the generation of Alfven waves and MHD turbulence. This work is supported by a NASA grant NNX08
Control-volume method for numerical simulation of two-phase immiscible flow in two-and
Firoozabadi, Abbas
Hydrology: Groundwater hydrology; 3210 Mathematical Geophysics: Modeling; 3230 Mathematical Geophysics. This concept, which is often referred to as the discrete-fracture model, has a significant effect. Introduction [2] There is wide interest in the numerical simulation of multiphase flow in fractured
Trinitis, C; Bader, M; Schulz, M
2009-06-09T23:59:59.000Z
In today's world, the use of parallel programming and architectures is essential for simulating practical problems in engineering and related disciplines. Significant progress in CPU architecture (multi- and many-core CPUs, SMT, transactional memory, virtualization support, shared caches etc.) system scalability, and interconnect technology, continues to provide new opportunities, as well as new challenges for both system architects and software developers. These trends are paralleled by progress in algorithms, simulation techniques, and software integration from multiple disciplines. In its 8th year, ParSim continues to build a bridge between application disciplines and computer science and to help fostering closer cooperations between these fields. Since its successful introduction in 2002, ParSim has established itself as an integral part of the EuroPVM/MPI conference series. In contrast to traditional conferences, emphasis is put on the presentation of up-to-date results with a short turn-around time. We believe that this offers a unique opportunity to present new aspects in this dynamic field and discuss them with a wide, interdisciplinary audience. The EuroPVM/MPI conference series, as one of the prime events in parallel computation, serves as an ideal surrounding for ParSim. This combination enables participants to present and discuss their work within the scope of both the session and the host conference. This year, five papers from authors in five countries were submitted to Par-Sim, and we selected three of them. They cover a range of different application fields including mechanical engineering, material science, and structural engineering simulations. We are confident that this resulted in an attractive special session and that this will be an informal setting for lively discussions as well as for fostering new collaborations. Several people contributed to this event. Thanks go to Jack Dongarra, the EuroPVM/MPI general chair, and to Jan Westerholm, Juha Fagerholm and Jussi Heikonen, the PC chairs, for their encouragement and support to continue the ParSim series at EuroPVM/MPI 2009. We would also like to thank the numerous reviewers, who provided us with their reviews in such a short amount of time (in most cases in just a few days) and thereby helped us to maintain the tight schedule. Last, but certainly not least, we would like to thank all those who took the time to submit papers and hence made this event possible in the first place. We are confident that this session will fulfill its purpose to provide new insights from both the engineering and the computer science side and encourages interdisciplinary exchange of ideas and cooperations, and that this will continue ParSim's tradition at EuroPVM/MPI.
Numerical Simulation and Analyses of the Loss of Feedwater Transient at the Unit 4 of Kola NPP
Stevanovic, Vladimir D. [University of Belgrade, Kraljice Marije 16, 11000 Belgrade, Serbia and Montenegro (Yugoslavia); Stosic, Zoran V.; Kiera, Michael; Stoll, Uwe [Framatome ANP GmbH, P.O. Box 3220, 91050 Erlangen (Germany)
2002-07-01T23:59:59.000Z
A three-dimensional numerical simulation of the loss-of-feed water transient at the horizontal steam generator of the Kola nuclear power plant is performed. Presented numerical results show transient change of integral steam generator parameters, such as steam generation rate, water mass inventory, outlet reactor coolant temperature, as well as detailed distribution of shell side thermal-hydraulic parameters: swell and collapsed levels, void fraction distributions, mass flux vectors, etc. Numerical results are compared with measurements at the Kola NPP. The agreement is satisfactory, while differences are close to or below the measurement uncertainties. Obtained numerical results are the first ones that give complete insight into the three-dimensional and transient horizontal steam generator thermal-hydraulics. Also, the presented results serve as benchmark tests for the assessment and further improvement of one-dimensional models of horizontal steam generator built with safety codes. (authors)
Intercomparison of numerical simulation codes for geologic disposal of CO2
2002-01-01T23:59:59.000Z
Study for Enhanced Coalbed Methane Recovery Processes, Partcapabilities are available. Coalbed methane simulators are
A new model for two-dimensional numerical simulation of pseudo-2D gas-solids fluidized beds
Li, Tingwen; Zhang, Yongmin
2013-10-11T23:59:59.000Z
Pseudo-two dimensional (pseudo-2D) fluidized beds, for which the thickness of the system is much smaller than the other two dimensions, is widely used to perform fundamental studies on bubble behavior, solids mixing, or clustering phenomenon in different gas-solids fluidization systems. The abundant data from such experimental systems are very useful for numerical model development and validation. However, it has been reported that two-dimensional (2D) computational fluid dynamic (CFD) simulations of pseudo-2D gas-solids fluidized beds usually predict poor quantitative agreement with the experimental data, especially for the solids velocity field. In this paper, a new model is proposed to improve the 2D numerical simulations of pseudo-2D gas-solids fluidized beds by properly accounting for the frictional effect of the front and back walls. Two previously reported pseudo-2D experimental systems were simulated with this model. Compared to the traditional 2D simulations, significant improvements in the numerical predictions have been observed and the predicted results are in better agreement with the available experimental data.
Course MA59800: Numerical Simulation in Applied Geophysics. From the Mesoscale to the Macroscale.
Santos, Juan
Description Wave propagation is a common technique used in hydrocarbon exploration geophysics, mining and reservoir characterization and production, among other fields. Local variations in the fluid and solid gradients via a slow-wave diffusion process that can be analyzed using numerical experiments. Numerical rock
E-Print Network 3.0 - assessment numerical simulation Sample...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
and Application Analysis Summary: design, software tuning Hardware :: Cycle-accurate simulation Software :: Execution-based profiling... Overview Hierarchical Clustering ::...
Bottoni, M.; Lyczkowski, R.; Ahuja, S.
1995-07-01T23:59:59.000Z
Numerical simulation of subcooled boiling in one-dimensional geometry with the Homogeneous Equilibrium Model (HEM) may yield difficulties related to the very low sonic velocity associated with the HEM. These difficulties do not arise with subcritical flow. Possible solutions of the problem include introducing a relaxation of the vapor production rate. Three-dimensional simulations of subcooled boiling in bundle geometry typical of fast reactors can be performed by using two systems of conservation equations, one for the HEM and the other for a Separated Phases Model (SPM), with a smooth transition between the two models.
Szilagyi, Bela; Buonanno, Alessandra; Taracchini, Andrea; Pfeiffer, Harald P; Scheel, Mark A; Chu, Tony; Kidder, Lawrence E; Pan, Yi
2015-01-01T23:59:59.000Z
We present the first numerical-relativity simulation of a compact-object binary whose gravitational waveform is long enough to cover the entire frequency band of advanced gravitational-wave detectors, such as LIGO, Virgo and KAGRA, for mass ratio 7 and total mass as low as $45.5\\,M_\\odot$. We find that effective-one-body models, either uncalibrated or calibrated against substantially shorter numerical-relativity waveforms at smaller mass ratios, reproduce our new waveform remarkably well, with a negligible loss in detection rate due to modeling error. In contrast, post-Newtonian inspiral waveforms and existing calibrated phenomenological inspiral-merger-ringdown waveforms display greater disagreement with our new simulation. The disagreement varies substantially depending on the specific post-Newtonian approximant used.
Bela Szilagyi; Jonathan Blackman; Alessandra Buonanno; Andrea Taracchini; Harald P. Pfeiffer; Mark A. Scheel; Tony Chu; Lawrence E. Kidder; Yi Pan
2015-02-17T23:59:59.000Z
We present the first numerical-relativity simulation of a compact-object binary whose gravitational waveform is long enough to cover the entire frequency band of advanced gravitational-wave detectors, such as LIGO, Virgo and KAGRA, for mass ratio 7 and total mass as low as $45.5\\,M_\\odot$. We find that effective-one-body models, either uncalibrated or calibrated against substantially shorter numerical-relativity waveforms at smaller mass ratios, reproduce our new waveform remarkably well, with a negligible loss in detection rate due to modeling error. In contrast, post-Newtonian inspiral waveforms and existing calibrated phenomenological inspiral-merger-ringdown waveforms display greater disagreement with our new simulation. The disagreement varies substantially depending on the specific post-Newtonian approximant used.
Esau, Igor
2010-01-01T23:59:59.000Z
Micrometeorology, city comfort, land use management and air quality monitoring increasingly become important environmental issues. To serve the needs, meteorology needs to achieve a serious advance in representation and forecast on micro-scales (meters to 100 km) called meteorological terra incognita. There is a suitable numerical tool, namely, the large-eddy simulation modelling (LES) to support the development. However, at present, the LES is of limited utility for applications. The study addresses two problems. First, the data assimilation problem on micro-scales is investigated as a possibility to recover the turbulent fields consistent with the mean meteorological profiles. Second, the methods to incorporate of the unresolved surface structures are investigated in a priopi numerical experiments. The numerical experiments demonstrated that the simplest nudging or Newtonian relaxation technique for the data assimilation is applicable on the turbulence scales. It is also shown that the filtering property of...
Saleh, Habeeb H.
2012-06-07T23:59:59.000Z
Sodium Flow Through FFTF Reactor Vessel 28 COLD LEG ISOLATION VALVE IIGG SELLDWS SEAL' HOT LEG ISOLATION VALVE QS" I t ?A OUTLET ' L'. : '. i NOZZLE '. : PESSARY~ PUMP IHX INLET NOZZLE CHECK VALVE SELLDWS SEAL' GRAVED MONITOR HOT LEG...NUMERICAL SIMULATION OF INTERMEDIATE HEAT EXCHANGER OF THE LIQUID METAL FAST BREEDER REACTOR USING COMMIX-1B A Thesis by HABEEB H. SALEH Submitted to the Office of Graduate Studies of Texas A@M University in partial fulfillment...
Zhang, Meng
2008-10-10T23:59:59.000Z
SATELLITE OBSERVATIONS AND NUMERICAL SIMULATIONS OF JET-FRONT GRAVITY WAVES OVER NORTH AMERICA AND NORTH ATLANTIC OCEAN A Thesis by MENG ZHANG Submitted to the Office of Graduate Studies of Texas A&M University in partial... OCEAN A Thesis by MENG ZHANG 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: Chair of Committee, Fuqing Zhang Committee...
Saez Barrios, Deeyvid O.
2010-07-14T23:59:59.000Z
: Chair of Committee, Jean-Louis Briaud Committee Members, Charles Aubeny Julian Kang Head of Department, John Niedzwecki Major Subject: Civil Engineering iii ABSTRACT Determination of Soil Properties of Sandy... Soils and Road Base at Riverside Campus Using Laboratory Testing and Numerical Simulation. (May 2010) Deeyvid Oscar Saez Barrios, B.En., Technological University of Panama Chair of Advisory Committee: Jean-Louis Briaud This study evaluated...
Wu, X.; Gao, J.; Wu, W.
2006-01-01T23:59:59.000Z
Doctor Instructor Professor The key laboratory of clean coal power generation and combustion technology of the ministry of education, southeast university College of energy sources & environment, Inner Mongolia University of Science & Technology...ICEBO2006, Shenzhen, China Maximize Comfort: Temperature, Humidity and IAQ Vol.I-7-1 Numerical Simulation of a Displacement Ventilation System with Multi-heat Sources and Analysis of Influential Factors Xuan Wu Jingfang Gao Wenfei Wu...
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 ...
Simulation of surface waves with porous boundaries in a 2-D numerical wave tank
Koo, Weoncheol
2012-06-07T23:59:59.000Z
with the BEM solutions. Good agreement is observed between the two independent solutions. After verifying the numerical methods, we studied the interaction of water waves with a porous or rigid bottom-mounted half cylinder. The reflection and transmission...
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. ...
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),
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 —
Loyka, Sergey
of inter- and intra-system electromagnetic interference (EMI). Using appropriate analysis and simulation Inter. Confer. on Electromagnetic Interference and Compatibility (INCEMIC'97), Dec. 3-5, Hyderabad
Sun, Biao
2012-01-01T23:59:59.000Z
??This PhD dissertation mainly studies the prediction, simulation and mitigation methods of the two main hazards in LNG (Liquefied Natural Gas) industry, LNG vapor dense… (more)
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.
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...
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.
Sun, P.; Fan, J.; Cen, K.
1999-07-01T23:59:59.000Z
In this work, an Eulerian/Lagrangian approach has been employed to investigate numerically flow characteristics, heat transfer and combustion processes inside corner-fired power plant boiler furnace. To avoid pseudo-diffusion that is significant in modeling tangentially-fired furnaces, some attempts have been made at improving the finite-difference scheme. Comparisons have been made between standard {kappa}-{epsilon} model and RNG {kappa}-{epsilon} model. Some new developments on turbulent diffusion of particles are taken into account in an attempt to improve computational accuracy. Finally, temperature deviation is studied numerically so as to gain deeper insight into tangentially fired furnace.
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.
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.
Duda, D.P.; Stephens, G.L.; Stevens, B.; Cotton, W.R. [Colorado State Univ., Fort Collins, CO (United States)] [Colorado State Univ., Fort Collins, CO (United States)
1996-12-15T23:59:59.000Z
Recent estimates of the effect of increasing of anthropogenic sulfate aerosol on the radiative forcing of the atmosphere have indicated that its impact may be comparable in magnitude to the effect from increases in CO{sub 2}. Much of this impact is expected from the effects of the aerosol on cloud microphysics and the subsequent impact on cloud albedo. A solar broadband version of a 2D radiative transfer model was used to quantify the impact of enhanced aerosol concentrations and horizontal inhomogeneity on the solar broadband albedo of marine stratus. The results of the radiative transfer calculations indicated that in unbroken marine stratus clouds the net horizontal transport of photons over a domain of a few kilometers was nearly zero, and the domain-average broadband albedo computed in a 2D cross section was nearly identical to the domain average calculated from a series of independent pixel approximation (IPA) calculations of the same cross section. However, the horizontal inhomogeneity does affect the cloud albedo compared to plane-parallel approximation (PPA) computations due to the nonlinear relationship between albedo and optical depth. The reduction in cloud albedo could be related to the variability of the distribution of log (cloud optical depth). These results extend the finding of Cahalan et al. to broadband solar albedos in a more realistic cloud model and suggest that accurate computation of domain-averaged broadband albedos in unbroken (or nearly unbroken) marine stratus can be made using IPA calculations with 1D radiative transfer models. Computations of the mean albedo over portions of the 3D RAMS domain show the relative increase in cloud albedo due to a 67% increase in the boundary-layer average CCN concentration was between 6% and 9%. The effects of cloud inhomogeneity on the broadband albedo as measured from the PPA bias ranged from 3% to 5%. 25 refs., 8 figs., 4 tabs.
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 ...
Numerical Simulation of Transient Fields F. Messerer, C. Trinitis*, W. Boeck, G. Schoffner
Stamatakis, Alexandros
and polarity reversal for HVDC systems are simulated as examples for the transient stresses. The application distribution of an HVDC system can be improved with a certain surface resistivity. With such a resistivity
Miami, University of
Loop Current Mixed Layer Energy Response to Hurricane Lili (2002). Part II: Idealized Numerical horizontal pressure gradient, wind energy transfer to the mixed layer can be more efficient in such a regime as compared to the case of an initially horizontally homogeneous ocean. However, nearly all energy is removed
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 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.
Domel, N.D.; Thompson, D.S. (Texas Univ., Arlington (USA))
1991-01-01T23:59:59.000Z
The effect of shock impingement on the mixing and combustion of a reacting shear-layer is numerically simulated. Hydrogen fuel is injected at sonic velocity behind a backward facing step in a direction parallel to a supersonic freestream vitiated with H{sub 2}O. The two-dimensional Navier-Stokes equations are solved and explicitly coupled to a chemistry package employing a global, two-step combustion model. The results show that shock impingement enhances the mixing and combustion. 17 refs.
Particle velocity based universal algorithm for numerical simulation of hydraulic fractures
Wrobel, Michal
2014-01-01T23:59:59.000Z
In the paper, we propose a new effective mathematical formulation and resulting universal numerical algorithm capable of tackling various HF models in the framework of a unified approach. The presented numerical scheme is not limited to any particular elasticity model or crack propagation regime. Its basic assumptions are: i) proper choice of independent and dependent variables (with the direct utilization of a new one - the reduced particle velocity), ii) tracing the fracture front by use of the speed equation which can be integrated in a closed form and sets an explicit relation between the crack propagation speed and the coefficients in the asymptotic expansion of the crack opening, iii) proper regularization techniques, iv) improved temporal approximation, v) modular algorithm architecture. The application of the new dependent variable, the reduced particle velocity, instead of the usual fluid flow rate, facilitates the computation of the crack propagation speed from the local relation based on the speed ...
Use of a speed equation for numerical simulation of hydraulic fractures
Linkov, Alexander M
2011-01-01T23:59:59.000Z
The paper treats the propagation of a hydraulically driven crack. We explicitly write the local speed equation, which facilitates using the theory of propagating interfaces. It is shown that when neglecting the lag between the liquid front and the crack tip, the lubrication PDE yields that a solution satisfies the speed equation identically. This implies that for zero or small lag, the boundary value problem appears ill-posed when solved numerically. We suggest e - regularization, which consists in employing the speed equation together with a prescribed BC on the front to obtain a new BC formulated at a small distance behind the front rather than on the front itself. It is shown that - regularization provides accurate and stable results with reasonable time expense. It is also shown that the speed equation gives a key to proper choice of unknown functions when solving a hydraulic fracture problem numerically.
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 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.
Regan, John A; Wise, John H
2015-01-01T23:59:59.000Z
We examine the impact of dark matter particle resolution on the formation of a baryonic core in high resolution adaptive mesh refinement simulations. We test the effect that both particle smoothing and particle splitting have on the hydrodynamic properties of a collapsing halo at high redshift (z > 20). Furthermore, we vary the background field intensity, with energy below the Lyman limit ( 100.0$ be satisfied, where ${M_{\\rm{core}}}$ is the enclosed baryon mass within the core and $M_{\\rm{DM}}$ is the minimum dark matter particle mass. This ratio should provide a very useful starting point for conducting convergence tests before any production run simulations. We find that dark matter particle smoothing is a useful adjunct to already highly resolved simulations.
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.
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...
Low level jet development during a numerically simulated return flow event
Igau, Richard Charles
1994-01-01T23:59:59.000Z
of the obstacle. This simulation shows that the structure of the lower tropospheric air flow during a period of return flow is complex. When mid-level westerlies are weak, mesoscale processes govern the development of low level jets. As the westerly winds increase...
Numerical simulation of Lewis number effects on lean premixed turbulent flames
turbulent flames for lean hydrogen, propane and methane mixtures in two dimensions. Each simulation or syngas, obtained from coal gasification, has sparked interest in the development of burners that can for propane, methane and hydrogen using de- tailed chemistry and transport, corresponding to Le > 1, Le 1
Peinke, Joachim
dynamics in full field. These data are badly needed for validation of so-called wake meandering models and finally methods of aeroelastic simulation of wind turbines in wake. Scope The proposed work aims.jose.trujillo@uni-oldenburg.de Fig. Near wake path of an offshore wind turbine estimatied by means of wake tracking #12;
Numerical simulation of flow distribution for pebble bed high temperature gas cooled reactors
Yesilyurt, Gokhan
2004-09-30T23:59:59.000Z
?....................................................................................26 V CFD MODELLING ...................................................................................28 V.1 Computational Fluid Dynamics (CFD) ..........................................28 V.2 The History.... Hassan The premise of the work presented here is to use a common analytical tool, Computational Fluid Dynamics (CFD), along with different turbulence models. Eddy viscosity models as well as state-of-the-art Large Eddy Simulation (LES) were...
Li, X.; Li, N.; Fang, F.; Zhao, D.
2006-01-01T23:59:59.000Z
Energy-efficient and cost-effective space conditioning in offices and other commercial buildings usually use the underfloor space for the supply air static-pressure plenum. The airflow in a plenum of the underfloor air supply was simulated by a...
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...
Full-scale numerical simulation scenarios using three-month observations of possible
Stuttgart, UniversitÃ¤t
and star-trackers data. Â· The simulation period was set to 32 days corresponding to the repeat cycle Â· Models for non-gravitational forces (transformed to acc data): air drag (MSIS86), solar radiation Â· Star-trackers data Measurement errors used for recovery : Â· SST observations: colored noise from If
M. Krause; M. Camenzind
2001-10-22T23:59:59.000Z
In the present paper, we examine the convergence behavior and inter-code reliability of astrophysical jet simulations in axial symmetry. We consider both, pure hydrodynamic jets and jets with a dynamically significant magnetic field. The setups were chosen to match the setups of two other publications, and recomputed with the MHD code NIRVANA. We show that NIRVANA and the two other codes give comparable, but not identical results. We find that some global properties of a hydrodynamical jet simulation, like e.g. the bow shock velocity, converge at 100 points per beam radius (ppb) with NIRVANA. The situation is quite different after switching on the toroidal magnetic field: In this case, global properties converge even at 10 ppb. In both cases, details of the inner jet structure and especially the terminal shock region are still insufficiently resolved, even at our highest resolution of 70 ppb in the magnetized case and 400 ppb for the pure hydrodynamic jet. In the case of our highest resolution simulation, we can report two new features: First, small scale Kelvin-Helmholtz instabilities are excited at the contact discontinuity next to the jet head. This slows down the development of the long wavelength Kelvin-Helmholtz instability and its turbulent cascade to smaller wavelengths. Second, the jet head develops Rayleigh-Taylor instabilities which manage to entrain an increasing amount of mass from the ambient medium with resolution. This region extends in our highest resolution simulation over 2 jet radii in the axial direction.
Evaluation of models for numerical simulation of the non-neutral region of sheath plasma
Boerner, Jeremiah J.; Boyd, Iain D. [Department of Aerospace Engineering, University of Michigan, Ann Arbor, FXB Building, 1320 Beal Avenue, Ann Arbor, Michigan 48109 (United States)
2009-07-15T23:59:59.000Z
Four different electron models are used to simulate the nonequilibrium plasma flow around a representative cylindrical Faraday probe geometry. Each model is implemented in a two-dimensional axisymmetric hybrid electron fluid and particle in cell method. The geometric shadowing model is derived from kinetic theory on the basis that physical obstruction of part of the velocity distribution leads to many of the expected sheath features. The Boltzmann electron fluid model relates the electron density to the plasma potential through the Boltzmann relation. The non-neutral detailed electron fluid model is derived from the electron conservation equations under the assumption of neutrality, and then modified to include non-neutral effects through the electrostatic Poisson equation. The Poisson-consistent detailed electron fluid model is also derived from the conservation equations and the electrostatic Poisson equation, but uses an alternative method that is inherently non-neutral from the outset. Simulations using the geometric shadowing and non-neutral detailed models do not yield satisfactory sheath structures, indicating that these models are not appropriate for sheath simulations. Simulations using the Boltzmann and Poisson-consistent models produce sheath structures that are in excellent agreement with the planar Bohm sheath solution near the centerline of the probe. The computational time requirement for the Poisson-consistent model is much higher than for the Boltzmann model and becomes prohibitive for larger domains.
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.
Perez, Jean Carlos; Chandran, Benjamin D. G. [Space Science Center, University of New Hampshire, Durham, NH 03824 (United States)
2013-10-20T23:59:59.000Z
We present direct numerical simulations of inhomogeneous reduced magnetohydrodynamic (RMHD) turbulence between the Sun and the Alfvén critical point. These are the first such simulations that take into account the solar-wind outflow velocity and the radial inhomogeneity of the background solar wind without approximating the nonlinear terms in the governing equations. RMHD turbulence is driven by outward-propagating Alfvén waves (z {sup +} fluctuations) launched from the Sun, which undergo partial non-WKB reflection to produce sunward-propagating Alfvén waves (z {sup –} fluctuations). We present 10 simulations with different values of the correlation time ?{sub c{sub sun}{sup +}} and perpendicular correlation length L{sub ?} of outward-propagating Alfvén waves at the coronal base. We find that between 15% and 33% of the z {sup +} energy launched into the corona dissipates between the coronal base and Alfvén critical point. Between 33% and 40% of this input energy goes into work on the solar-wind outflow, and between 22% and 36% escapes as z {sup +} fluctuations through the simulation boundary at r = r{sub A}. The z {sup ±} power spectra scale like k{sub perpendicular}{sup -?{sup ±}}, where k is the wavenumber in the plane perpendicular to B{sub 0}. In our simulation with the smallest value of ?{sub c{sub sun}{sup +}} (?2 minutes) and largest value of L{sub ?} (2 × 10{sup 4} km), we find that ?{sup +} decreases approximately linearly with increasing ln (r), reaching a value of 1.3 at r = 11.1 R{sub ?}. Our simulations with larger values of ?{sub c{sub sun}{sup +}} exhibit alignment between the contours of constant ?{sup +}, ?{sup –}, ?{sub 0}{sup +}, and ?{sub 0}{sup -}, where ?{sup ±} are the Elsässer potentials and ?{sub 0}{sup ±} are the outer-scale parallel Elsässer vorticities.
Building ventilation : a pressure airflow model computer generation and elements of
Paris-Sud XI, UniversitÃ© de
Building ventilation : a pressure airflow model computer generation and elements of validation H Abstract : The calculation of airflows is of great importance for detailed building thermal simulation the building and the outside on one hand, and the different thermal zones on the other. The driving effects
Domanus, H.M.; Sha, W.T.
1981-01-01T23:59:59.000Z
The single-phase COMMIX (COMponent MIXing) computer code performs fully three-dimensional, transient, thermal-hydraulic analyses of liquid-sodium LMFBR components. It solves the conservation equations of mass, momentum, and energy as a boundary-value problem in space and as an initial-value problem in time. The concepts of volume porosity, surface permeability and distributed resistance, and heat source have been employed in quasi-continuum (rod-bundle) applications. Results from three transient simulations involving forced and natural convection are presented: (1) a sodium-filled horizontal pipe initially of uniform temperature undergoing an inlet velocity rundown transient, as well as an inlet temperature transient; (2) a 19-pin LMFBR rod bundle undergoing a velocity transient; and, (3) a simulation of a water test of a 1/10-scale outlet plenum undergoing both velocity and temperature transients.
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.
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.
Numerical simulations of the internal shock model in magnetized relativistic jets of blazars
Rueda-Becerril, Jesus M; Aloy, Miguel A
2015-01-01T23:59:59.000Z
The internal shocks scenario in relativistic jets is used to explain the variability of the blazar emission. Recent studies have shown that the magnetic field significantly alters the shell collision dynamics, producing a variety of spectral energy distributions and light-curves patterns. However, the role played by magnetization in such emission processes is still not entirely understood. In this work we numerically solve the magnetohydodynamic evolution of the magnetized shells collision, and determine the influence of the magnetization on the observed radiation. Our procedure consists in systematically varying the shell Lorentz factor, relative velocity, and viewing angle. The calculations needed to produce the whole broadband spectral energy distributions and light-curves are computationally expensive, and are achieved using a high-performance parallel code.
Use of Silicon Carbide as Beam Intercepting Device Material: Tests, Issues and Numerical Simulations
Delonca, M; Gil Costa, M; Vacca, A
2014-01-01T23:59:59.000Z
Silicon Carbide (SiC) stands as one of the most promising ceramic material with respect to its thermal shock resistance and mechanical strengths. It has hence been considered as candidate material for the development of higher performance beam intercepting devices at CERN. Its brazing with a metal counterpart has been tested and characterized by means of microstructural and ultrasound techniques. Despite the positive results, its use has to be evaluated with care, due to the strong evidence in literature of large and permanent volumetric expansion, called swelling, under the effect of neutron and ion irradiation. This may cause premature and sudden failure, and can be mitigated to some extent by operating at high temperature. For this reason limited information is available for irradiation below 100°C, which is the typical temperature of interest for beam intercepting devices like dumps or collimators. This paper describes the brazing campaign carried out at CERN, the results, and the theoretical and numeric...
Numerical simulation of material and energy flow in an e-beam melt furnace
Westerberg, K.W.; McClelland, M.A. [Lawrence Livermore National Lab., CA (United States); Finlayson, B.A. [Washington Univ., Seattle, WA (United States). Dept. of Chemical Engineering
1993-12-01T23:59:59.000Z
A numerical analysis is made of the material and energy flow in an electron-beam furnace. Energy from an electron beam vaporizes metal confined in a water-cooled crucible. At the beam impact site a. recirculating liquid metal pool is surrounded by a shell of its own solid. A Galerkin finite element method is modified to solve for the flow and temperature fields along with interface locations. The deforming mesh is parameterized using spines that pivot and stretch as the interfaces move. Results are given for an aluminum vaporizer in which parametric variations are made in the e-beam power and liquid viscosity. The calculations reveal the importance of the coupling between the free boundaries and the flow and energy fields.
E. I. Vorobyov; Shantanu Basu
2004-11-29T23:59:59.000Z
We perform numerical hydrodynamic modeling of various physical processes that can form an HI ring as is observed in Holmberg I. Three energetic mechanisms are considered: multiple supernova explosions (SNe), a hypernova explosion associated with a gamma ray burst (GRB), and the vertical impact of a high velocity cloud (HVC). The total released energy has an upper limit of 10^54 ergs. We find that multiple SNe are in general more effective in producing shells that break out of the disk than a hypernova explosion of the same total energy. As a consequence, multiple SNe form rings with a high ring-to-center contrast K 45 deg) the HI image is characterized by two kidney-shaped density enhancements and a mild central depression.
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.
Numerical simulation of bump-on-tail instability with source and sink
Berk, H.L.; Pekker, M. [Texas Univ., Austin, TX (United States). Inst. for Fusion Studies; Breizman, B.N. [Texas Univ., Austin, TX (United States). Inst. for Fusion Studies]|[Budker Inst. of Nuclear Physics, Novosibirsk (Russian Federation)
1995-02-01T23:59:59.000Z
This paper presents results of the simulations of the bump-on-tail instability with a weak source and sink. This problem has been posed as a paradigm for the important problem in controlled fusion, that of the unstable excitation of Alfven waves in a tokamak by resonant energetic alpha particles. The source of alpha particles is the controlled fusion reaction produced by the background plasma and the sink is the collisional transport processes that slow down or scatter the energetic particles. The mathematical techniques that are needed to address this applied problem can be demonstrated in the much simpler bump-on-tail problem, which is explained in this paper.
Numerical simulation study of positron production by intense laser-accelerated electrons
Yan, Yonghong [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China) [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Science and Technology on Plasma Physics Laboratory, Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Dong, Kegong; Wu, Yuchi; Zhang, Bo; Gu, Yuqiu [Science and Technology on Plasma Physics Laboratory, Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China)] [Science and Technology on Plasma Physics Laboratory, Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Yao, Zeen [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China)] [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China)
2013-10-15T23:59:59.000Z
Positron production by ultra-intense laser-accelerated electrons has been studied with two-dimensional particle-in-cell and Monte Carlo simulations. The dependence of the positron yield on plasma density, plasma length, and converter thickness was investigated in detail with fixed parameters of a typical 100 TW laser system. The results show that with the optimal plasma and converter parameters a positron beam containing up to 1.9 × 10{sup 10} positrons can be generated, which has a small divergence angle (10°), a high temperature (67.2 MeV), and a short pulse duration (1.7 ps)
Numerical simulation of the operation of piston rings in a reciprocating engine
Saghir, H.; Arques, P. [Centrale School of Lyon, Ecully (France)
1995-12-31T23:59:59.000Z
In this paper, the authors present results concerning the tightness of a combustion chamber by rings placed on a piston. The authors have developed a program of simulation of the operation of rings on a piston in movement. This program takes into account: the unstationary reciprocating movement of the ring in the piston ring groove and flows of gases between the combustion chamber, volumes delimited by the set rings-piston-cylinder and the crankcase. These flows are executed in rear of the ring or directly by the clearance to the cup of the ring.
Quiros Fonseca, Luis Alonso
2012-12-31T23:59:59.000Z
. . . . . . . . . . 139 xvi ahfhfhg Nomenclature ? Density c Specific Heat cp Specific Heat cs Specific Heat in Solid Phase cps Specific Heat in Solid Phase cl Specific Heat in Liquid Phase cpl Specific Heat in Liquid Phase k Thermal Conductivity ks Thermal Conductivity... the movement of the front during evo- lution. In most applications of interest, simulation of the formation of the transition region i.e. solid-liquid interface is essential as it may not be possible to know its location a priori. 6 These limitations have...
Non-linear numerical simulations of magneto-acoustic wave propagation in small-scale flux tubes
E. Khomenko; M. Collados; T. Felipe
2008-01-25T23:59:59.000Z
We present results of non-linear, 2D, numerical simulations of magneto-acoustic wave propagation in the photosphere and chromosphere of small-scale flux tubes with internal structure. Waves with realistic periods of three to five minutes are studied, after applying horizontal and vertical oscillatory perturbations to the equilibrium model. Spurious reflections of shock waves from the upper boundary are minimized thanks to a special boundary condition. This has allowed us to increase the duration of the simulations and to make it long enough to perform a statistical analysis of oscillations. The simulations show that deep horizontal motions of the flux tube generate a slow (magnetic) mode and a surface mode. These modes are efficiently transformed into a slow (acoustic) mode in the vA propagates vertically along the field lines, forms shocks and remains always within the flux tube. It might deposit effectively the energy of the driver into the chromosphere. When the driver oscillates with a high frequency, above the cut-off, non-linear wave propagation occurs with the same dominant driver period at all heights. At low frequencies, below the cut-off, the dominant period of oscillations changes with height from that of the driver in the photosphere to its first harmonic (half period) in the chromosphere. Depending on the period and on the type of the driver, different shock patterns are observed.
Numerical simulation of thin-shell direct drive DHe3-filled capsules fielded at OMEGA
Miles, A. R.; Chung, H.-K.; Heeter, R.; Hsing, W.; Koch, J. A.; Park, H.-S.; Robey, H. F.; Scott, H. A.; Tommasini, R. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Frenje, J.; Li, C. K.; Petrasso, R. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Glebov, V. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Lee, R. W. [SLAC Linear Coherent Light Source, Menlo Park, California 94025 (United States)
2012-07-15T23:59:59.000Z
Thin-shell deuterium-helium-3 (DHe{sup 3}) filled glass capsules on the Omega laser provide a fast-implosion experimental platform for developing separate time-resolved measurements of ion, electron, and radiation temperatures in nonequilibrium plasmas. Dynamically significant non-local thermodynamic equilibrium (NLTE) conditions are created by the addition of xenon dopant to the DHe{sup 3} gas fill, in quantities sufficient to have an impact on yields, compression, and cooling rates. The high-Z dopant dramatically increases the radiative cooling rate in the plasma, allowing it to collapse in compressions that can be an order of magnitude higher than in undoped capsules. A baseline LASNEX simulation model using detailed configuration accounting NLTE atomic physics shows very good agreement with the data for doped as well as undoped capsules, while other models either underpredict or overpredict the radiative cooling enhancement. The baseline model captures the behavior of the capsule when the D:He{sup 3} ratio is varied well away from equimolar, suggesting no yield anomaly with either nearly pure deuterium or He{sup 3} fills. Variation of the electron-ion coupling in the baseline simulation model shows agreement with the data for a coupling multiplier that is within 20% of unity. Reliably inferring electron-ion coupling strength from the data is complicated by uncertainties in the hydrodynamic mix and other parameters, but many of these can be mitigated in follow-on experiments at the National Ignition Facility.
H. Rafii-Tabar; H. R. Sepangi
2005-08-30T23:59:59.000Z
The stochastic dynamics of inclusions in a randomly fluctuating biomembrane is simulated. These inclusions can represent the embedded proteins and the external particles arriving at a cell membrane. The energetics of the biomembrane is modelled via the Canham-Helfrich Hamiltonian. The contributions of both the bending elastic-curvature energy and the surface tension of the biomembrane are taken into account. The biomembrane is treated as a two-dimensional sheet whose height variations from a reference frame is treated as a stochastic Wiener process. The lateral diffusion parameter associated with this Wiener process coupled with the longitudinal diffusion parameter obtained from the standard Einsteinian diffusion theory completely determine the stochastic motion of the inclusions. It is shown that the presence of surface tension significantly affects the overall dynamics of the inclusions, particularly the rate of capture of the external inclusions, such as drug particles, at the site of the embedded inclusions, such as the embedded proteins.
Mapping galaxy encounters in numerical simulations: The spatial extent of induced star formation
Moreno, Jorge; Ellison, Sara L; Patton, David R; Bluck, Asa F L; Bansal, Gunjan; Hernquist, Lars
2015-01-01T23:59:59.000Z
We employ a suite of 75 simulations of galaxies in idealised major mergers (stellar mass ratio ~2.5:1), with a wide range of orbital parameters, to investigate the spatial extent of interaction-induced star formation. Although the total star formation in galaxy encounters is generally elevated relative to isolated galaxies, we find that this elevation is a combination of intense enhancements within the central kpc and moderately suppressed activity at large galacto-centric radii. The radial dependence of the star formation enhancement is stronger in the less massive galaxy than in the primary, and is also more pronounced in mergers of more closely aligned disc spin orientations. Conversely, these trends are almost entirely independent of the encounter's impact parameter and orbital eccentricity. Our predictions of the radial dependence of triggered star formation, and specifically the suppression of star formation beyond kph-scales, will be testable with the next generation of integral-field spectroscopic sur...
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.
Graessley, W.W.; Grest, G.S.; Hayward, R.C.
1999-03-23T23:59:59.000Z
The effect of excluded volume on the coil size of dilute linear polymers was investigated by off-lattice Monte Carlo simulations. The radius of gyration R{sub g} was evaluated for a wide range of chain lengths at several temperatures and at the athermal condition. The theta temperature and the corresponding theta chain dimensions were established for the system, and the dependence of the size expansion factor, a{sub s} = R{sub g} /(R{sub g}){sub {theta}}, on chain length N and temperature T was examined. For long chains and at high temperatures, a{sub s} is a function of N/N{sub s}{sup 2} alone, where the length scale N{sub s}{sup 2} depends only on T. The form of this simulations-based master function compares favorably with {alpha}{sub s}(M/M{sub s}{sup 2}), an experimental master curve for linear polymers in good solvents, where M{sub s}{sup 2} depends only on polymer-solvent system. Comparisons when N{sub s}{sup 2}(T) and M{sub s}{sup 2}(system) are reduced to common units, numbers of Kuhn steps, strongly indicate that coil expansion in even the best of good solvents is small relative to that expected for truly athermal solutions. An explanation for this behavior is proposed, based on what would appear to be an inherent difference in the equation of state properties for polymeric and monomeric liquids.
Numerical Simulation of Hydrodynamics of a Heavy Liquid Drop Covered by Vapor Film in a Water Pool
Ma, W.M.; Yang, Z.L.; Giri, A.; Sehgal, B.R. [Royal Institute of Technology (KTH), Drottning Kristinas vaeg 33 A, 100 44, Stockholm (Sweden)
2002-07-01T23:59:59.000Z
A numerical study on the hydrodynamics of a droplet covered by vapor film in water pool is carried out. Two level set functions are used as to implicitly capture the interfaces among three immiscible fluids (melt-drop, vapor and coolant). This approach leaves only one set of conservation equations for the three phases. A high-order Navier-Stokes solver, called Cubic-Interpolated Pseudo-Particle (CIP) algorithm, is employed in combination with level set approach, which allows large density ratios (up to 1000), surface tension and jump in viscosity. By this calculation, the hydrodynamic behavior of a melt droplet falling into a volatile coolant is simulated, which is of great significance to reveal the mechanism of steam explosion during a hypothetical severe reactor accident. (authors)
Hongzhi Lan; Soojung Claire Hur; Dino Di Carlo; Damir B. Khismatullin
2013-06-19T23:59:59.000Z
The effects of cell size and deformability on the lateral migration and deformation of living cells flowing through a rectangular microchannel has been numerically investigated and compared with the inertial-microfluidics data on detection and separation of cells. The results of this work indicate that the cells move closer to the centerline if they are bigger and/or more deformable and that their equilibrium position is largely determined by the solvent (cytosol) viscosity, which is much less than the polymer (cytoskeleton) viscosity measured in most rheological systems. Simulations also suggest that decreasing channel dimensions leads to larger differences in equilibrium position for particles of different viscoelastic properties, giving design guidance for the next generation of microfluidic cell separation chips.
Modeling-Computer Simulations At Long Valley Caldera Geothermal...
and components of two continuous GPS time series. Additionally, the model explains the spatial extent of deformation observed by InSAR data covering the 1997-98 inflation...
Modeling-Computer Simulations At Fenton Hill HDR Geothermal Area...
of the Fenton Hill HDR Reservoir Donald W. Brown (1994) How to Achieve a Four-Fold Productivity Increase at Fenton Hill Additional References Retrieved from "http:en.openei.org...
Modeling-Computer Simulations At Valles Caldera - Sulphur Springs...
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 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 Long Valley Caldera Geothermal...
of a rock matrix with finite hydraulic conductivity cut by a steeply dipping fracture with infinite hydraulic conductivity. For this model to match the pressure data the...
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 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 Walker-Lane Transitional Zone...
and earthquake-monitoring projects, and data donated from mining, geothermal, and petroleum companies. We also collected (May 2002 and August 2004) two new crustal refraction...
Modeling-Computer Simulations (Combs, Et Al., 1999) | Open Energy
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Modeling-Computer Simulations (Laney, 2005) | Open Energy Information
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Modeling-Computer Simulations (Lewicki & Oldenburg, 2004) | Open Energy
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Modeling-Computer Simulations (Ozkocak, 1985) | Open Energy Information
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Modeling-Computer Simulations (Ranalli & Rybach, 2005) | Open Energy
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Modeling-Computer Simulations (Walker, Et Al., 2005) | Open Energy
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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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformation Lewicki(Blackwell, Et Al.,
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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformation Lewicki(Blackwell, Et
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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformation Lewicki(Blackwell,Et 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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformation Lewicki(Blackwell,EtEt 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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker, 1983) |
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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker, 1983) |(Farrar, Et
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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker, 1983) |(Farrar,
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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker, 1983)Et|2008) |
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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker, 1983)Et|2008)
Modeling-Computer Simulations At Valles Caldera - Sulphur Springs
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Modeling-Computer Simulations At Yellowstone Region (Laney, 2005) | Open
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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 Home5b9fcbce19 No revision hasInformation Earth's HeatMexico: EnergyMithun Jump to: navigation, searchGritto & Majer) Jump
Modeling-Computer Simulations At Long Valley Caldera Geothermal Area
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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 Home5b9fcbce19 No revision hasInformation Earth's HeatMexico: EnergyMithun Jump to: navigation, searchGritto(Tempel, Et Al.,
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 Home5b9fcbce19 No revision hasInformation Earth's HeatMexico: EnergyMithun Jump to: navigation, searchGritto(Tempel,Reiter,(Wilt
Chen, Jacqueline H.; Hawkes, Evatt R.; Sankaran, Ramanan [Reacting Flow Research Department, Combustion Research Facility, Sandia National Laboratories, P.O. Box 969 MS 9051, Livermore, CA 94551-0969 (United States); Mason, Scott D. [Lockheed Martin Corporation, Sunnyvale, CA 94089 (United States); Im, Hong G. [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109-2125 (United States)
2006-04-15T23:59:59.000Z
The influence of thermal stratification on autoignition at constant volume and high pressure is studied by direct numerical simulation (DNS) with detailed hydrogen/air chemistry with a view to providing better understanding and modeling of combustion processes in homogeneous charge compression-ignition engines. Numerical diagnostics are developed to analyze the mode of combustion and the dependence of overall ignition progress on initial mixture conditions. The roles of dissipation of heat and mass are divided conceptually into transport within ignition fronts and passive scalar dissipation, which modifies the statistics of the preignition temperature field. Transport within ignition fronts is analyzed by monitoring the propagation speed of ignition fronts using the displacement speed of a scalar that tracks the location of maximum heat release rate. The prevalence of deflagrative versus spontaneous ignition front propagation is found to depend on the local temperature gradient, and may be identified by the ratio of the instantaneous front speed to the laminar deflagration speed. The significance of passive scalar mixing is examined using a mixing timescale based on enthalpy fluctuations. Finally, the predictions of the multizone modeling strategy are compared with the DNS, and the results are explained using the diagnostics developed. (author)
J. L. Mietta; R. M. Negri; P. I. Tamborenea
2014-05-04T23:59:59.000Z
In this article we explore how structural parameters of composites filled with one-dimensional, electrically conducting elements (such as sticks, needles, chains, or rods) affect the percolation properties of the system. To this end, we perform Monte Carlo simulations of asymmetric two-dimensional stick systems with anisotropic alignments. We compute the percolation probability functions in the direction of preferential orientation of the percolating objects and in the orthogonal direction, as functions of the experimental structural parameters. Among these, we considered the average length of the sticks, the standard deviation of the length distribution, and the standard deviation of the angular distribution. We developed a computer algorithm capable of reproducing and verifying known theoretical results for isotropic networks and which allows us to go beyond and study anisotropic systems of experimental interest. Our research shows that the total electrical anisotropy, considered as a direct consequence of the percolation anisotropy, depends mainly on the standard deviation of the angular distribution and on the average length of the sticks. A conclusion of practical interest is that we find that there is a wide and well-defined range of values for the mentioned parameters for which it is possible to obtain reliable anisotropic percolation under relatively accessible experimental conditions when considering composites formed by dispersions of sticks, oriented in elastomeric matrices.
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 via parallel-distributed computing of energy absorption by metal deformation
Plaskacz, E.J.; Kulak, R.F.
1995-07-01T23:59:59.000Z
Collapsible steering column designs are credited with saving tens-of-thousands of lives since their introduction in the late 1960`s. The collapsible steering column is a safety feature designed to absorb energy and protect-the driver in a head-on collision. One of the most frequently used design concepts employs two telescoping metal tubes that slide over one another as the occupant impacts the steering wheel. Hardened steel ball bearings are embedded in a plastic sleeve located between the two tubes. There are two primary mechanisms for energy absorption during steering column collapse. One is the friction between the bearing and tube surfaces. Another is the gouging of the tubes` surfaces by the bearings. Current analytical models are unable to adequately capture the physics behind this process. In this paper we will present an overview of a parallel finite element code, currently under development, that can be used to simulate the highly nonlinear response of this energy absorbing mechanism. Our parallel algorithms are constructed on a message-passing foundation. The actual message-passing implementation used was the Argonne-developed p4 package. However, other message-passing libraries can easily be accommodated as they are largely identical in function and differ only in syntax. Once the algorithm is restructured as a set of processes communicating through messages, the program can run on systems as diverse as a uniprocessor workstation, multiprocessors with and without shared memory, a group of workstations that communicate over a local network, or any combination of the above. Benchmarks of the parallel code performance on networks of workstations and the IBM SP1 parallel supercomputer will be discussed.
Mahalingam, S. [Colorado Univ., Boulder, CO (United States). Dept. of Mechanical Engineering; Chen, J.H. [Sandia National Labs., Livermore, CA (United States); Vervisch, L. [Institut de Mecanique des Fluides, Numeriques (France)
1994-01-01T23:59:59.000Z
Three-dimensional Direct Numerical Simulations (DNS) of turbulent non-premixed flames including finite-rate chemistry and heat release effects were performed. Two chemical reaction models were considered: (1) a single-step global reaction model in which the heat release and activation energy parameters are chosen to model methane-air combustion, and (2) a two-step reaction model to simulate radical production and consumption and to compare against the single-step model. The model problem consists of the interaction between an initially unstrained laminar diffusion flame and a three-dimensional field of homogeneous turbulence. Conditions ranging from fast chemistry to the pure mixing limit were studied by varying a global Damkoehler number. Results suggest that turbulence-induced mixing acting along the stoichiometric line leads to a strong modification of the inner structure of the turbulent flame compared with a laminar strained flame, resulting in intermediate species concentrations well above the laminar prediction. This result is consistent with experimental observations. Comparison of the response of the turbulent flame structure due to changes in the scalar dissipation rate with a steady strained laminar flame reveals that unsteady strain rates experienced by the turbulent flame may be responsible for the observed high concentrations of reaction intermediates.
Pruess, Karsten
2003-04-13T23:59:59.000Z
The critical point of CO2 is at temperature and pressureconditions of Tcrit = 31.04oC, Pcrit = 73.82 bar. At lower (subcritical)temperatures and/or pressures, CO2 can exist in two different phases, aliquid and a gaseous state, as well as in two-phase mixtures of thesestates. Disposal of CO2 into brine formations would be made atsupercritical pressures. However, CO2 escaping from the storage reservoirmay migrate upwards towards regions with lower temperatures andpressures, where CO2 would be in subcritical conditions. An assessment ofthe fate of leaking CO2 requires a capability to model not onlysupercritical but also subcritical CO2, as well as phase changes betweenliquid and gaseous CO2 in sub-critical conditions. We have developed amethodology for numerically simulating the behavior of water-CO2 mixturesin permeable media under conditions that may include liquid, gaseous, andsupercritical CO2. This has been applied to simulations of leakage from adeep storage reservoir in which a rising CO2 plume undergoes transitionsfrom supercritical to subcritical conditions. We find strong coolingeffects when liquid CO2 rises to elevations where it begins to boil andevolve a gaseous CO2 phase. A three-phase zone forms (aqueous - liquid -gas), which over time becomes several hundred meters thick as decreasingtemperatures permit liquid CO2 to advance to shallower elevations. Fluidmobilities are reduced in the three-phase region from phase interferenceeffects. This impedes CO2 upflow, causes the plume to spread outlaterally, and gives rise to dispersed CO2 discharge at the land surface.Our simulations suggest that temperatures along a CO2 leakage path maydecline to levels low enough so that solid water ice and CO2 hydratephases may be formed.
Lignell, David O. [Department of Chemical Engineering, University of Utah, Salt Lake City, UT 84098 (United States); Reacting Flow Research Department, Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551 (United States); Chen, Jacqueline H. [Reacting Flow Research Department, Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551 (United States); Smith, Philip J. [Department of Chemical Engineering, University of Utah, Salt Lake City, UT 84098 (United States); Lu, Tianfeng; Law, Chung K. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08540 (United States)
2007-10-15T23:59:59.000Z
Direct numerical simulations of a two-dimensional, nonpremixed, sooting ethylene flame are performed to examine the effects of soot-flame interactions and transport in an unsteady configuration. A 15-step, 19-species (with 10 quasi-steady species) chemical mechanism was used for gas chemistry, with a two-moment, four-step, semiempirical soot model. Flame curvature is shown to result in flames that move, relative to the fluid, either toward or away from rich soot formation regions, resulting in soot being essentially convected into or away from the flame. This relative motion of flame and soot results in a wide spread of soot in the mixture fraction coordinate. In regions where the center of curvature of the flame is in the fuel stream, the flame motion is toward the fuel and soot is located near the flame at high temperature and hence has higher reaction rates and radiative heat fluxes. Soot-flame breakthrough is also observed in these regions. Fluid convection and flame displacement velocity relative to fluid convection are of similar magnitudes while thermophoretic diffusion is 5-10 times lower. These results emphasize the importance of both unsteady and multidimensional effects on soot formation and transport in turbulent flames. (author)
Paris-Sud XI, UniversitÃ© de
Numerical Simulations Skin-Effect Description in Electromagnetism with a Scaled Asymptotic Expansion Gabriel.08.2009 V. PÂ´eron Skin-Effect Description in Electromagnetism with a Scaled Asymptotic Expansion 1 / 32 and Electromagnetism MONIQUE DAUGE, ERWAN FAOU, VICTOR P Â´ERON (2009) Asymptotic Behavior at High Conductivity of Skin
Mohaghegh, Shahab
SPE 153844 Grid-Based Surrogate Reservoir Modeling (SRM) for Fast Track Analysis of Numerical Reservoir Simulation Models at the Grid block Level Shahab D. Mohaghegh, West Virginia University the wellbores. The method is called Grid-Based Surrogate Reservoir Model (SRM) since it is has the unique
Malapaka, Shiva Kumar; Mueller, Wolf-Christian [Max-Planck Institute for Plasma Physics, Boltzmannstrasse 2, D-85748 Garching bei Muenchen (Germany)
2013-09-01T23:59:59.000Z
Statistical properties of the Sun's photospheric turbulent magnetic field, especially those of the active regions (ARs), have been studied using the line-of-sight data from magnetograms taken by the Solar and Heliospheric Observatory and several other instruments. This includes structure functions and their exponents, flatness curves, and correlation functions. In these works, the dependence of structure function exponents ({zeta}{sub p}) of the order of the structure functions (p) was modeled using a non-intermittent K41 model. It is now well known that the ARs are highly turbulent and are associated with strong intermittent events. In this paper, we compare some of the observations from Abramenko et al. with the log-Poisson model used for modeling intermittent MHD turbulent flows. Next, we analyze the structure function data obtained from the direct numerical simulations (DNS) of homogeneous, incompressible 3D-MHD turbulence in three cases: sustained by forcing, freely decaying, and a flow initially driven and later allowed to decay (case 3). The respective DNS replicate the properties seen in the plots of {zeta}{sub p} against p of ARs. We also reproduce the trends and changes observed in intermittency in flatness and correlation functions of ARs. It is suggested from this analysis that an AR in the onset phase of a flare can be treated as a forced 3D-MHD turbulent system in its simplest form and that the flaring stage is representative of decaying 3D-MHD turbulence. It is also inferred that significant changes in intermittency from the initial onset phase of a flare to its final peak flaring phase are related to the time taken by the system to reach the initial onset phase.
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)
2010-10-18T23:59:59.000Z
Data from a 1152X760X1280 direct numerical simulation (DNS) [N. J. Mueschke and O. Schilling, Phys. Fluids 21, 014106 (2009)] 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.
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
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.
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.
Tavassoli, Armin
1999-01-01T23:59:59.000Z
grid system. In this thesis, several flow configurations, such as stationary and oscillating cylinder, were studied in order to predict and to understand the hydrodynamic forces. The results from the different simulations were compared with available...
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 ...
Oldenburg, C.M.
2013-01-01T23:59:59.000Z
simulation of reservoir depletion and oil flow from themodel included the oil reservoir and the well with a toppressures of the deep oil reservoir, to a two-phase oil-gas
Chen, Qingyan "Yan"
for the correct prediction of the convective heat. A finer grid resolution in CFD does not always lead to a more conservation equations of flow on these grid cells. As shown in Figure 1(a), CFD calculates convective heat1 NUMERICAL DETERMINATION AND TREATMENT OF CONVECTIVE HEAT TRANSFER COEFFICIENT IN THE COUPLED
Numerical Simulations of Violent Free Surface by a Coupled Level-Set and Volume-of-Fluid Method
Zhao, Yucheng
2014-04-18T23:59:59.000Z
................................................................................ 57 4.6 3D Dam Breaking Flow ................................................................................ 59 4.7 3D Dam Breaking Flow with Cylindrical Pillar ............................................ 62 CHAPTER V SLOSHING FLOW... IN PARTIALLY FILLED LNG TANK ....... 65 5.1 Introduction ................................................................................................... 65 5.2 Experimental and Numerical Setups...
Huang, Xun
19th. AIAA-CEAS Aeroacoutics Conference, May 28th 2013, Berlin Dynamic Modeling and Numerical was presented in this paper. By this control-oriented model, transient dynamic process of multi-physics coupling problem in a progressive wave tube could be approximately studied. The proposed model is verified
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.
Hinch, John
CB3 0WA, UK b University of Cambridge, BP Institute & Engineering Department, Madingley Road, Cambridge CB3 0EZ, UK Received 17 January 2006; received in revised form 11 April 2006; accepted 11 April of view. Rasmussen and Hassager [1,2] simulate creeping flows of viscoelastic fluids described
Boppa, Praneetha
2012-10-19T23:59:59.000Z
. The behavior of dynamic pressure profiles at different operating conditions, and the effect of a central groove on dynamic pressure profiles were also studied. Simulation results of a 3D case which is similar to the one experimentally studied by Delgado were...
Geddes, Cameron Guy Robinson
-principles (e.g., Particle-In-Cell), for particle acceler- ation devices or problems such as: particle beams OF PARTICLE J.-L. Vay , W. M. Fawley, C. G. R. Geddes, E. Cormier-Michel, LBNL, Berkeley, CA, USA D. P. Grote to perform computer simulations in a boosted frame for a certain class of systems: particle beams inter
Castro Gouveia, M. de; Reis Parise, J.A. dos; Nieckele, A.O. (Pontificia Univ. Catolica, Rio de Janeiro (Brazil))
1992-05-01T23:59:59.000Z
A numerical simulation of the scavenging process in a two-stroke flat-piston model engine has been developed. Air enters the cylinder circumferentially, inducting a three-dimensional turbulent swirling flow. The problem was modeled as a steady-state axisymmetric flow through a cylinder with uniform wall temperature. The steady-state regime was simulated by assuming the piston head fixed at the bottom dead center. The calculation was performed employing the {kappa}-{epsilon} model of turbulence. A comparison of the results obtained for the flow field with available experimental data showed very good agreement, and a comparison with an available numerical solution revealed superior results. The effects of the Reynolds number, inlet port angles, and engine geometry on the flow and in-cylinder heat transfer characteristics were investigated. The Nusselt number substantially increases with larger Reynolds numbers and a smaller bore-to-stroke ratio. It is shown that the positioning of the exhaust value(s) is the main parameter to control the scavenging process.
Mack, J H; Dibble, R W; Buchholz, B A; Flowers, D L
2004-01-16T23:59:59.000Z
Despite the rapid combustion typically experienced in Homogeneous Charge Compression Ignition (HCCI), components in fuel mixtures do not ignite in unison or burn equally. In our experiments and modeling of blends of diethyl ether (DEE) and ethanol (EtOH), the DEE led combustion and proceeded further toward completion, as indicated by {sup 14}C isotope tracing. A numerical model of HCCI combustion of DEE and EtOH mixtures supports the isotopic findings. Although both approaches lacked information on incompletely combusted intermediates plentiful in HCCI emissions, the numerical model and {sup 14}C tracing data agreed within the limitations of the single zone model. Despite the fact that DEE is more reactive than EtOH in HCCI engines, they are sufficiently similar that we did not observe a large elongation of energy release or significant reduction in inlet temperature required for light-off, both desired effects for the combustion event. This finding suggests that, in general, HCCI combustion of fuel blends may have preferential combustion of some of the blend components.
Is a Direct Numerical Simulation of Chaos or Turbulence Possible: A Study of a Model Non-Linearity
Lun-Shin Yao
2006-04-17T23:59:59.000Z
There are many subtle issues associated with solving the Navier-Stokes equations. In this paper, several of these issues, which have been observed previously in research involving the Navier-Stokes equations, are studied within the framework of the one-dimensional Kuramoto-Sivashinsky (KS) equation, a model nonlinear partial-differential equation. This alternative approach is expected to more easily expose major points and hopefully identify open questions that are related to the Navier-Stokes equations. In particular, four interesting issues are discussed. The first is related to the difficulty in defining regions of linear stability and instability for a time-dependent governing parameter; this is equivalent to a time-dependent base flow for the Navier-Stokes equations. The next two issues are consequences of nonlinear interactions. These include the evolution of the solution by exciting its harmonics or sub-harmonics (Fourier components) simultaneously in the presence of a constant or a time-dependent governing parameter; and the sensitivity of the long-time solution to initial conditions. The final issue is concerned with the lack of convergent numerical chaotic solutions, an issue that has not been previously studied for the Navier-Stokes equations. The last two issues, consequences of nonlinear interactions, are not commonly known. Conclusions and questions uncovered by the numerical results are discussed. The reasons behind each issue are provided with the expectation that they will stimulate interest in further study.
Cook, C.; Richmond, M.; Coleman, A. (Pacific Northwest National Laboratory)
2003-06-01T23:59:59.000Z
Summer temperatures in the Lower Snake River can be altered by releasing cold waters that originate from deep depths within Dworshak Reservoir. These cold releases are used to lower temperatures in the Clearwater and Lower Snake Rivers and to improve hydrodynamic and water quality conditions for migrating aquatic species. This project monitored the complex three-dimensional hydrodynamic and thermal conditions at the Clearwater and Snake River confluence and the processes that led to stratification of Lower Granite Reservoir (LGR) during the late spring, summer, and fall of 2002. Hydrodynamic, water quality, and meteorological conditions around the reservoir were monitored at frequent intervals, and this effort is continuing in 2003. Monitoring of the reservoir is a multi-year endeavor, and this report spans only the first year of data collection. In addition to monitoring the LGR environment, a three-dimensional hydrodynamic and water quality model has been applied. This model uses field data as boundary conditions and has been applied to the entire 2002 field season. Numerous data collection sites were within the model domain and serve as both calibration and validation locations for the numerical model. Errors between observed and simulated data varied in magnitude from location to location and from one time to another. Generally, errors were small and within expected ranges, although, as additional 2003 field data becomes available, model parameters may be improved to minimize differences between observed and simulated values. A two-dimensional, laterally-averaged hydrodynamic and water quality model was applied to the three reservoirs downstream of LGR (the pools behind Little Goose, Lower Monumental, and Ice Harbor Dams). A two-dimensional model is appropriate for these reservoirs because observed lateral thermal variations during summer and fall 2002 were almost negligible; however, vertical thermal variations were quite large (see USACE 2003). The numerical model was applied to each reservoir independently to simulate the time period between May 1 and October 1, 2002. Differences between observed and simulated data were small, although improvements to model coefficients may be performed as additional thermal data, collected in the reservoirs during 2003, becomes available.
Apte, Sourabh V.
in rivers, fluidized beds, coal-based oxy-fuel combustion cham- bers, biomass gasifiers, among others is first validated for flow over a fixed sphere at various Reynolds numbers and flow generated by a freely
Li Xuechen; Niu Dongying; Yin Zengqian [College of Physics Science and Technology, Hebei University, Baoding 071002 (China); Fang Tongzhen; Wang Long [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)
2012-08-15T23:59:59.000Z
The characteristics of dielectric barrier discharge excited by a saw-tooth voltage are simulated in atmospheric pressure helium based on a one-dimensional fluid model. A stepped discharge is obtained per half voltage cycle with gas gap width less than 2 mm by the simulation, which is different to the pulsed discharge excited by a sinusoidal voltage. For the stepped discharge, the plateau duration increases with increasing the voltage amplitude and decreasing the gas gap. Therefore, uniform discharge with high temporal duty ratio can be realized with small gap through increasing the voltage amplitude. The maximal densities of both electron and ion appear near the anode and the electric field is almost uniformly distributed along the gap, which indicates that the stepped discharge belongs to a Townsend mode. In contrast to the stepped discharge with small gas gap, a pulsed discharge can be obtained with large gas gap. Through analyzing the spatial density distributions of electron and ion and the electric field, the pulsed discharge is in a glow mode. The voltage-current (V-I) characteristics are analyzed for the above mentioned discharges under different gas gaps, from which the different discharge modes are verified.
Constantine, Paul; Larsson, Johan; Iaccarino, Gianluca
2014-01-01T23:59:59.000Z
We present a computational analysis of the reactive flow in a hypersonic scramjet engine with emphasis on effects of uncertainties in the operating conditions. We employ a novel methodology based on active subspaces to characterize the effects of the input uncertainty on the scramjet performance. The active subspace re-parameterizes the operating conditions from seven well characterized physical parameters to a single derived active variable. This dimension reduction enables otherwise intractable---given the cost of the simulation---computational studies to quantify uncertainty; bootstrapping provides confidence intervals on the studies' results. In particular we (i) identify the parameters that contribute the most to the variation in the output quantity of interest, (ii) compute a global upper and lower bound on the quantity of interest, and (iii) classify sets of operating conditions as safe or unsafe corresponding to a threshold on the output quantity of interest. We repeat this analysis for two values of ...
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.
Stosic, Zoran V. [Framatome ANP GmbH, PO Box 3220, Erlangen, 91050 (Germany); Stevanovic, Vladimir D. [University of Belgrade, Kraljice Marije 16, 11000 Belgrade, Serbia and Montenegro (Yugoslavia); Tadashi Iguchi [Japan Atomic Energy Research Institute, Tokai-mura 319-1195 (Japan)
2002-07-01T23:59:59.000Z
The investigation of three-dimensional transient propagations of dry-out fronts within a nuclear fuel rod bundle is performed, based on experimental and numerical simulations. The spreading of Critical Heat Flux (CHF) fronts across a bundle, caused by sudden decrease of coolant mass flow rate followed by delayed gradual decrease of power generation is predicted, and the locus of dry patches is shown. Simultaneous occurrence of CHF and re-wet multi-fronts in here-analysed flow transient has not been detected so obvious as in power transient, previously analysed. Due to a possible building of a vapour zone, the CHF front spatial propagation has to be carefully analysed in transient conditions. (authors)
Xu, Tianfu; Rose, Peter; Fayer, Scott; Pruess, Karsten
2009-02-01T23:59:59.000Z
Dissolution of silica, silicate, and calcite minerals in the presence of a chelating agent (NTA) at a high pH has been successfully performed in the laboratory using a high-temperature flow reactor. The mineral dissolution and porosity enhancement in the laboratory experiment has been reproduced by reactive transport simulation using TOUGHREACT. The chemical stimulation method has been applied by numerical modeling to a field geothermal injection well system, to investigate its effectiveness. Parameters from the quartz monzodiorite unit at the Enhanced Geothermal System (EGS) site at Desert Peak (Nevada) were used. Results indicate that the injection of a high pH chelating solution results in dissolution of both calcite and plagioclase minerals, and avoids precipitation of calcite at high temperature conditions. Consequently reservoir porosity and permeability can be enhanced especially near the injection well.
Rajan, V S P
2006-01-01T23:59:59.000Z
The Scaled Boundary Finite Element Method is a novel semi-analytical method jointly developed by Chongmin Song and John P Wolf to solve problems in elastodynamics and allied problems in civil engineering. This novel method has been recently reformulated for the following categories of problems in electromagnetics: (1) Determination of Eigen values of metallic cavity structures, 2) Full wave analysis of Shielded micro-strip transmission line structures, and Very Large Scale Integrated Circuit (VLSI) interconnects, and 3) Full wave analysis of periodic structures. In this paper, a novel Scaled Boundary Finite Element formulation is developed for the numerical simulation of the time harmonic electromagnetic radiation in free space from metallic structures of arbitrary shape. The development of the novel formulation necessitates the generalization of the familiar Atkinson-Wilcox radiation series expansion so as to be applicable for arbitrary boundary circumscribing the source of radiation.
Peter Diener; Brajesh Gupt; Parampreet Singh
2014-05-16T23:59:59.000Z
A key result of isotropic loop quantum cosmology is the existence of a quantum bounce which occurs when the energy density of the matter field approaches a universal maximum close to the Planck density. Though the bounce has been exhibited in various matter models, due to severe computational challenges some important questions have so far remained unaddressed. These include the demonstration of the bounce for widely spread states, its detailed properties for the states when matter field probes regions close to the Planck volume and the reliability of the continuum effective spacetime description in general. In this manuscript we rigorously answer these questions using the Chimera numerical scheme for the isotropic spatially flat model sourced with a massless scalar field. We show that as expected from an exactly solvable model, the quantum bounce is a generic feature of states even with a very wide spread, and for those which bounce much closer to the Planck volume. We perform a detailed analysis of the departures from the effective description and find some expected, and some surprising results. At a coarse level of description, the effective dynamics can be regarded as a good approximation to the underlying quantum dynamics unless the states correspond to small scalar field momenta, in which case they bounce closer to the Planck volume, or are very widely spread. Quantifying the amount of discrepancy between the quantum and the effective dynamics, we find that the departure between them depends in a subtle and non-monotonic way on the field momentum and different fluctuations. Interestingly, the departures are generically found to be such that the effective dynamics overestimates the spacetime curvature, and underestimates the volume at the bounce.
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
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.
Numerical simulation of hydraulic fracturing
Warner, Joseph Barnes
1987-01-01T23:59:59.000Z
of Eq. 21, in its present form, is unstable. The change in fracture cell volume over the time step, BV/At, must be known to calculate pressures at the new time level. Since the value of the AV/At term is dependent on the pressure being solved for... is unconditionally stable and, therefore, guarantees a solution for any time step size~s. To implicitly expand the AV/At term, the pressure change component Ap /At must be extracted so that pex(t+At) can be placed ex on the left hand side of Eq. 21. The AV...
Numerical Simulations of Bouncing Jets
Lee, Sanghyun
2014-07-18T23:59:59.000Z
downhill gliding of the pool, at about 4mm/s of pool surface velocity. . . . . . . . . . . . . . . . . . . . . . 87 viii 5.7 Overall view of the shampoo jet bouncing of an inclined pool of the same liquid. The white arrow points at he breakup of the air....4 Time discretization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 3.5 Entropy residual stabilization . . . . . . . . . . . . . . . . . . . . . . 58 3.6 Adaptive mesh refinement . . . . . . . . . . . . . . . . . . . . . . . . 61 iv 3.7...
Numerical Simulation of Transpiration Cooling
University, Templergraben 55, 52056 Aachen SUMMARY Transpiration cooling using ceramic matrix composite (CMC
Numerical simulation in oil recovery
Wheeler, M.F.
1988-01-01T23:59:59.000Z
The major research emphasis in this book is on the modeling of fractures, heterogeneities, viscous fingering, and diffusion-dispersion effects in the flow in porous media. This volume contains seventeen papers on the latest developments. Its diverse presentation brings together the various disciplines of applied mathematics, chemical engineering, physics and hydrology.
Pruess, Karsten
2003-03-31T23:59:59.000Z
The critical point of CO{sub 2} is at temperature and pressure conditions of T{sub crit} = 31.04 C, P{sub crit} = 73.82 bar. At lower (subcritical) temperatures and/or pressures, CO{sub 2} can exist in two different phase states, a liquid and a gaseous state, as well as in two-phase mixtures of these states. Disposal of CO{sub 2} into brine formations would be made at supercritical pressures. However, CO{sub 2} escaping from the storage reservoir may migrate upwards towards regions with lower temperatures and pressures, where CO{sub 2} would be in subcritical conditions. An assessment of the fate of leaking CO{sub 2} requires a capability to model not only supercritical but also subcritical CO{sub 2}, as well as phase changes between liquid and gaseous CO{sub 2} in sub-critical conditions. We have developed a methodology for numerically simulating the behavior of water-CO{sub 2} mixtures in permeable media under conditions that may include liquid, gaseous, and supercritical CO{sub 2}. This has been applied to simulations of leakage from a deep storage reservoir in which a rising CO{sub 2} plume undergoes transitions from supercritical to subcritical conditions. We find strong cooling effects when liquid CO{sub 2} rises to elevations where it begins to boil and evolve a gaseous CO{sub 2} phase. A three-phase zone forms (aqueous - liquid - gas), which over time becomes several hundred meters thick as decreasing temperatures permit liquid CO{sub 2} to advance to shallower elevations. Fluid mobilities are reduced in the three-phase region from phase interference effects. This impedes CO{sub 2} upflow, causes the plume to spread out laterally, and gives rise to dispersed CO{sub 2} discharge at the land surface. Our simulation suggests that temperatures along a CO{sub 2} leakage path may decline to levels low enough so that solid water ice and CO{sub 2} hydrate phases may be formed.
Uncertainty and error in computational simulations
Oberkampf, W.L.; Diegert, K.V.; Alvin, K.F.; Rutherford, B.M.
1997-10-01T23:59:59.000Z
The present paper addresses the question: ``What are the general classes of uncertainty and error sources in complex, computational simulations?`` This is the first step of a two step process to develop a general methodology for quantitatively estimating the global modeling and simulation uncertainty in computational modeling and simulation. The second step is to develop a general mathematical procedure for representing, combining and propagating all of the individual sources through the simulation. The authors develop a comprehensive view of the general phases of modeling and simulation. The phases proposed are: conceptual modeling of the physical system, mathematical modeling of the system, discretization of the mathematical model, computer programming of the discrete model, numerical solution of the model, and interpretation of the results. This new view is built upon combining phases recognized in the disciplines of operations research and numerical solution methods for partial differential equations. The characteristics and activities of each of these phases is discussed in general, but examples are given for the fields of computational fluid dynamics and heat transfer. They argue that a clear distinction should be made between uncertainty and error that can arise in each of these phases. The present definitions for uncertainty and error are inadequate and. therefore, they propose comprehensive definitions for these terms. Specific classes of uncertainty and error sources are then defined that can occur in each phase of modeling and simulation. The numerical sources of error considered apply regardless of whether the discretization procedure is based on finite elements, finite volumes, or finite differences. To better explain the broad types of sources of uncertainty and error, and the utility of their categorization, they discuss a coupled-physics example simulation.
Effective velocities in fractured media: a numerical study using the ...
2002-03-18T23:59:59.000Z
and precise numerical study of effective velocities in fractured structures. ... In this paper, we ..... A final result is that our numerical simulations of P-, SV- and.
Modeling-Computer Simulations At Akutan Fumaroles Area (Kolker, Et Al.,
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Modeling-Computer Simulations At Central Nevada Seismic Zone Region (Biasi,
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Modeling-Computer Simulations At Chocolate Mountains Area (Alm, Et Al.,
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Modeling-Computer Simulations At Coso Geothermal Area (1999) | Open Energy
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Modeling-Computer Simulations At Dixie Valley Geothermal Area (Kennedy &
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Modeling-Computer Simulations At Dixie Valley Geothermal Area (Wisian &
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Modeling-Computer Simulations At Fenton Hill HDR Geothermal Area (Brown &
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Modeling-Computer Simulations At Fenton Hill HDR Geothermal Area (Goff &
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Modeling-Computer Simulations At Fish Lake Valley Area (Deymonaz, Et Al.,
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Modeling-Computer Simulations At Hawthorne Area (Lazaro, Et Al., 2010) |
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Modeling-Computer Simulations At Kilauea East Rift Geothermal Area (Rudman
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Modeling-Computer Simulations At Nevada Test And Training Range Area
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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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker, 1983)
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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker, 1983)Et Al., 2003) |
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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker, 1983)Et Al., 2003)
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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker, 1983)Et Al.,
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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker, 1983)Et Al.,Al., 2003)
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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker, 1983)Et Al.,Al.,
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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker, 1983)Et Al.,Al.,| Open
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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker, 1983)Et Al.,Al.,|
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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker, 1983)Et
Modeling-Computer Simulations At Stillwater Area (Wisian & Blackwell, 2004)
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Modeling-Computer Simulations At The Needles Area (Bell & Ramelli, 2009) |
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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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker, 1983)Et| OpenEnergy
Modeling-Computer Simulations At U.S. West Region (Sabin, Et Al., 2004) |
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Modeling-Computer Simulations At U.S. West Region (Williams & Deangelo,
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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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker,(Biasi, Et Al., 2009) |
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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker,(Biasi, Et Al., 2009)
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 CenterFranconia, Virginia: Energy Resources Jump to:46 -Energieprojekte GmbHMilo, Maine:EnergyInformationDecker,(Biasi, Et Al.,
Modeling-Computer Simulations At White Mountains Area (Goff & Decker, 1983)
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Modeling-Computer Simulations At Coso Geothermal Area (1980) | 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 Home5b9fcbce19 No revision hasInformation Earth's HeatMexico: EnergyMithun Jump to: navigation, searchGritto & Majer)
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,
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 Home5b9fcbce19 No revision hasInformation Earth's HeatMexico: EnergyMithun Jump to: navigation, searchGritto &Open
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 Home5b9fcbce19 No revision hasInformation Earth's HeatMexico: EnergyMithun Jump to: navigation, searchGritto(Tempel, Et
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 Home5b9fcbce19 No revision hasInformation Earth's HeatMexico: EnergyMithun Jump to: navigation, searchGritto(Tempel, EtEnergy
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 Home5b9fcbce19 No revision hasInformation Earth's HeatMexico: EnergyMithun Jump to: navigation, searchGritto(Tempel,
Modeling-Computer Simulations At San Juan Volcanic Field Area (Clarkson &
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Khandare, Milind Nandkumar
2012-02-14T23:59:59.000Z
of SFDs can be expensive and time consuming. The current work simulates the flow field inside the dynamically deforming annular gap of a SFD using the commercial computational fluid dynamics (CFD) code Fluent and compares the results to the experimental...
Numerical Investigations of Magnetohydrodynamic Hypersonic Flows.
Guarendi, Andrew N
2013-01-01T23:59:59.000Z
??Numerical simulations of magnetohydrodynamic (MHD) hypersonic flow are presented for both laminar and turbulent flow over a cylinder and flow entering a scramjet inlet. ANSYS… (more)
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)...
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...
D'Sousa, Cedric Benedict
1997-01-01T23:59:59.000Z
realized information on the hood entry losses and other design parameters that are of interest to the users, designers and owners of fume hoods. After the specification of the problem and generation of the mesh, the modeled hood was simulated using CFD...
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.
Vadillo, D.C.; Tembely, M.; Morrison, N.F.; Harlen, O.G.; Mackley, M.R.; Soucemarianadin, A.
D. C. Vadillo*1, M. Tembely**2, N.F. Morrison3, O. G. Harlen3, M. R. Mackley1 10 and A. Soucemarianadin***2 11 12 1Department of Chemical Engineering and Biotechnology, University of Cambridge, 13 CB2 3RA, UK 14 2Laboratory for Geophysical... . Rasmussen, P-Y. Longin, and O. Hassager, “Growth of non-635 axisymmetric disturbances of the free surface in the filament stretching rheometer: 636 Experiments and simulation,” J. Non-Newtonian Fluid Mech. 180, 163–186 (2002). 637 Bazilevsky A. V., V. M...
Douglas W. Marshall; Changhu Xing; Charles Folsom; Colby Jensen; Heng Ban
2014-05-01T23:59:59.000Z
As an important factor affecting the accuracy of the thermal conductivity measurement, systematic (bias) error in the guarded comparative axial heat flow (cut-bar) method was mostly neglected by previous researches. This bias is due primarily to the thermal conductivity mismatch between sample and meter bars (reference), which is common for a sample of unknown thermal conductivity. A correction scheme, based on a finite element simulation of the measurement system, was proposed to reduce the magnitude of the overall measurement uncertainty. This scheme was experimentally validated by applying corrections on four types of sample measurements in which the specimen thermal conductivity is much smaller, slightly smaller, equal and much larger than that of the meter bar. As an alternative to the optimum guarding technique proposed before, the correction scheme can be used to minimize uncertainty contribution from the measurement system with non-optimal guarding conditions. It is especially necessary for large thermal conductivity mismatches between sample and meter bars.
LaVenue, A.M.; Haug, A.; Kelley, V.A.
1988-03-01T23:59:59.000Z
This hydrogeologic modeling study has been performed as part of the regional hydrologic characterization of the Waste Isolation Pilot Plant (WIPP) Site in southeastern New Mexico. The study resulted in an estimation of the transmissivity distrubution, hydraulic potentials, flow field, and fluid densities in the Culebra Dolomite Member of the Permian Rustler Formation at the WIPP site. The three-dimensional finite-difference code SWIFT-II was employed for the numerical modeling, using variable-fluid-density and a single-porosity formulation. The modeled area includes and extends beyond the WIPP controlled zone (Zone 3). The work performed consisted of modeling the hydrogeology of the Culebra using two approaches: (1) steady-state modeling to develop the best estimate of the undisturbed head distribution, i.e., of the situation before sinking if the WIPP shafts, which began in 1981; and (2) superimposed transient modeling of local hydrologic responses to excavation of the three WIPP shafts at the center of the WIPP site, as well as to various well tests. Boundary conditions (prescribed constant fluid pressures and densities) were estimated using hydraulic-head and fluid-density data obtained from about 40 wells at and near the WIPP site. The transient modeling used the calculated steady-state freshwater heads as initial conditions. 107 refs., 112 figs., 22 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: ...
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.
Numerical Relativity at the Frontier
Stuart L. Shapiro
2005-09-23T23:59:59.000Z
Numerical relativity is an essential tool for solving Einstein's equations of general relativity for dynamical systems characterized by high velocities and strong gravitational fields. The implementation of new algorithms that can solve these nonlinear equations in 3+1 dimensions has enabled us to tackle many long-standing problems of astrophysical interest, leading to an explosion of important new results. Numerical relativity has been used to simulate the evolution of a diverse array of physical systems, including coalescing black hole and neutron star binaries, rotating and collapsing compact objects (stars, collisionless clusters, and scalar fields), and magnetic and viscous stars, to name a few. Numerical relativity has been exploited to address fundamental points of principle, including critical phenomena and cosmic censorship. It holds great promise as a guide for interpreting observations of gravitational waves and gamma-ray bursts and identifying the sources of such radiation. Highlights of a few recent developments in numerical relativity are sketched in this brief overview.
Numerical Methodology to Evaluate Fast Reactor Sodium Combustion
Yamaguchi, Akira; Takata, Takashi; Okano, Yasushi [Japan Nuclear Cycle Development Institute (Japan)
2001-12-15T23:59:59.000Z
In the present study, a numerical methodology for sodium combustion has been developed for the safety evaluation of a liquid-metal-cooled fast reactor. The methodology includes a fast-running zone model computer program for safety evaluation, a field model program for multidimensional thermal hydraulics, and a chemical reaction analysis program based on chemical equilibrium theory. Two recently performed experiments have been analyzed using the computer programs, and the numerical results are in good agreement with the experiments. Although sodium combustion is a complex phenomenon, use of these computer programs gives better understanding of the coupled thermal hydraulics and chemical reaction.
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 ...
A numerical sensitivity analysis of streamline simulation
Chaban Habib, Fady Ruben
2005-02-17T23:59:59.000Z
of the finite-difference flow equations. In order to find the position of the particle, its movement through a three- dimensional finite-difference cell must be considered. Let?s start with the rate of change in the particle?s x-component of velocity... were performed to determine the effects of various influential elements on the stability and results of the solution. Those experiments were applied to various models to identify the impact of factors such as mobility ratios, mapping of saturation...
NUMERICAL SIMULATION OF MULTIPOLE CONFINEMENT (Examples)
Sprott, Julien Clinton
delphia APS meeting in November 1973. All cases are for neutral H 2 background. The excitation energy loss energy, so that little ionization occurs. As a result, the density builds steadily to a maximum at late at ionizing the neutrals. This ionization raises the charged particle density and thus lowers the heating rate
Direct Numerical Simulation of Cosmological Reionization /
So, Geoffrey C.
2013-01-01T23:59:59.000Z
2004). We are focusing on EoR which occured after the “Dark2004). We are focusing on EoR which occured after the “DarkEpoch of Reionization” (EoR). In Figure 1.1, a brief history
Numerical simulation of an energy storage well
Ebeling, Lynn Louis
2012-06-07T23:59:59.000Z
~ Isothera aap oC ~ at the end of 0. 25 yr. of in]ectiou. . ~ ~ ~ ~ ~ ~ ~ . ~ . ~ ~ . ~ 48 7 ~ Isobar aap, Rilopascals, after 0. 25 yr. of storaqe. 49 8. Isothera aap, oC ~ after 0 25 yr. of stozaqe. . . . ~ 50 9 Isobar nap. Rilopascal, after 0 ~ 25 yr...-recovery schedules to insure an economical operation and to prevent theraal pollution of the aquifer. Sa~iaal 511~I mayer and Todd (1973) did preliminary calculations for a well in a 33 a thick confined aquifer of 25 percent poros- ity. The well received 99o...
Numerical simulation and modeling of carbon nanotubes.
Wong, Chee How.
2008-01-01T23:59:59.000Z
??The discovery of carbon nanotubes has triggered a significant amount of interest. Since then, much research has been done on these new forms of carbon… (more)
Numerical simulation of sandstone reservoir models
Gross, Stephen Joseph
1983-01-01T23:59:59.000Z
. Case 3 - Alternatin h1 h and low ermeabilities Waterflood performance of the Case 3 reservoir is shown in Figures 19 and 20. The process 1s practically rate insensitive for both the high and low viscosity ratio cases because of the ex istence... The results of the water flood study indicate that lower rates result i n higher waterflood oil recoveries from heterogeneous reservoirs, particularly where high oil-water viscosity ratios exist. These results support the conclusions of Jordan et. al...
Numerical Simulations ANSYS FLUENT 14.0
California at San Diego, University of
-cooled divertor with multi-pin array (HEMP) Â· FZK design1 used array of fins (vs. jet impingement) to cool surface
Numerical Simulation of Condensation in Transonic Flows
Twente, Universiteit
set of governing equations . . . . . . . . . . . . . . . . . . 21 2.3.8 Speed of sound equations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.3.1 Gas-liquid mixtures of the liquid phase . . . . . . . . . . . . . . . . . . . . . 14 2.3.4 Alternative derivation of Hill's Method
Numerical simulations in laser controlled fusion
Afanas'ev, Y.V.; Busurina, L.N.; Volosevich, P.P.; Galiguzova, I.I.; Gamalii, E.G.; Gus'kov, S.Y.; Danilova, G.V.; Krokhin, O.N.; Kurdyumov, S.P.; Levanov, E.I.
1983-07-01T23:59:59.000Z
Various theoretical models for the events which occur in laser targets are discussed. Difference methods are used to solve the corresponding problems. The results calculated by the LUCH program at the Institute of Applied Mathematics are compared with experiments carried out in the Kal'mar device (Lebedev Physics Institute, Moscow) and in the USA (at the KMS Fusion laboratory) in the Argus and Shiva devices. The theoretical and experimental results are in satisfactory agreement over broad ranges of the laser power density. It is also shown that the results calculated by the code of the Institute of Applied Mathematics and by the code of the Lawrence Livermore Laboratory (LASNEX) under identical physical assumptions are approximately the same.
NUMERICAL SIMULATION OF INCOMPRESSIBLE FLOWS IN ...
u, v and w respectively, and f, g, h, q are functions depending on the solutions at .... and letting A, B, C, D, E, F and U be the corresponding matrices with entries.
The Numerical Approximation of Solutions of ... - Purdue University
2009-05-05T23:59:59.000Z
numerical simulation of waterflooding of heterogeneous petroleum reservoirs. Computational Geosciences, 1 (1997). 155–190. J. Douglas, Jr., C.-S. Huang, and ...
E-Print Network 3.0 - adaptive numerical methods Sample Search...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
- Fachbereich Mathematik und Informatik, Philipps-Universitt Marburg Collection: Mathematics 2 Introduction Adaptive wavelet numerical simulation Turbulence modelling Summary...
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.
Causality and sensitivity analysis in distributed design simulation
Kim, Jaehyun, 1970-
2002-01-01T23:59:59.000Z
Numerous collaborative design frameworks have been developed to accelerate the product development, and recently environments for building distributed simulations have been proposed. For example, a simulation framework ...
Numerical techniques for lattice gauge theories
Creutz, M.
1981-02-06T23:59:59.000Z
The motivation for formulating gauge theories on a lattice is reviewed. Monte Carlo simulation techniques are then discussed for these systems. Finally, the Monte Carlo methods are combined with renormalization group analysis to give strong numerical evidence for confinement of quarks by non-Abelian gauge fields.
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 ...
Numerical study of high heat ux pool boiling heat transfer Ying He a,*, Masahiro Shoji b
Maruyama, Shigeo
Numerical study of high heat Â¯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
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 ...
A numerical investigation of collisionality and turbulent transport
Lindsey, Martin L., S.B. Massachusetts Institute of Technology
2014-01-01T23:59:59.000Z
An investigation of collisionality's role in turbulent transport in magnetized plasma using the GS2 gyrokinetic simulation software is presented. The investigation consists of three parts, conducted by way of numerical ...
2005-10-20T23:59:59.000Z
Required tools: Matlab routine dfield ; numerical routines eul, rk2, rk4; m-files. Discussion ... You should get a piecewise linear graph made up .... in the matrix y
Numerical Analysis Gordon K. Smyth
Smyth, Gordon K.
Numerical Analysis Gordon K. Smyth May 1997 Numerical analysis is concerned with the accurate discipline of numerÂ ical analysis is almost entirely a product of the period since 1950 during which biostatisticians can benefit from familiarity with numerical analysis. An understanding of the numerical methods
E-Print Network 3.0 - acoustic sources numerical Sample Search...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
analytical or numerical so- lutions. The natural physical and acoustical data are limited in accuracy... 400 150 250 350 SOURCE RECEIVER 1 RECEIVER 2 Simulation Experiment ......
E-Print Network 3.0 - adaptive numerical dissipative Sample Search...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
rate. Through numerical simulations, we find... description (i) Dissipative, vortex-vortex forces ... Source: Grzybowski, Bartosz A. - Departments of Chemistry & Chemical...
Frey, Pascal
. Frey1,2 1UPMC Univ Paris 06, UMR 7598, Laboratoire J.L. Lions, F-75005 Paris, France 2Universidad de present a three-dimensional numerical simulation on a mechanical device. Copyright 2011 John Wiley & Sons.L. Lions, F-75005 Paris, France. E-mail: debuhan@ann.jussieu.fr Copyright 2011 John Wiley & Sons, Ltd. #12
RisR1448(EN) Numerical Study of the
is the better understanding of the physics of the aeroelastic motion of wind turbine blades in order to improve of wind turbine blades in order to improve the numerical simulation of such dynamical systems. In previous works, both aerodynamic damping cal- culations and fully-coupled aeroelastic simulations of wind turbine
Computing Flowpipe of Nonlinear Hybrid Systems with Numerical Methods
Boyer, Edmond
(which embed information on the plant dynamics) are more and more used: for such systems, the controller simulation used nowadays are very powerful and efficient to approximate the behavior of complex dynamical guaranteed generalization of classical efficient numerical simulation methods, including with variable
VALIDATION OF MASSIVELY PARALLEL SIMULATIONS OF DYNAMIC FRACTURE AND
Barr, Al
VALIDATION OF MASSIVELY PARALLEL SIMULATIONS OF DYNAMIC FRACTURE AND FRAGMENTATION OF BRITTLE element simulations of dynamic fracture and fragmentation of brittle solids are presented. Fracture the results of massively parallel numerical simulations of dynamic fracture and fragmentation in brittle
Studied models Numerical scheme
Helluy, Philippe
: Sound speed: c0 = 1500m/s Pressure: p0 = 105Pa Density: 0 = 1000kg/m3 Vapor: 1 = 1.4 (1 = 0) Water: 2. Helluy, S. MÂ¨uller HÂ´el`ene Mathis Micro-Macro Modelling and Simulation of Liquid-Vapour Flows #12 approximations HÂ´el`ene Mathis Micro-Macro Modelling and Simulation of Liquid-Vapour Flows #12;Studied models
Numerical control user experience
Butler, J.
1985-10-01T23:59:59.000Z
AUTOCON is an acronym for Automatic Contouring, a program which generates a contour toolpath for the external profile of printed writing boards (PWB) using ICEM DDN. AUTOCON originates from the Computer Aided Process Planning (CAPP) Procedure developed by Electrical Manufacturing at Allied Bendix. The CAPP program uses electronically transmitted graphics files received from a design agency to generate automatic panel layouts and travellers for Process Engineers. The objective of AUTOCON is to utilize the information from the CAPP program to generate Numerical Control tapes. If the CAPP program can be utilized to its full potential, it is estimated that a good portion of the 60 to 90 PWB tapes shipped each month from our Numerical Control Department could be eliminated from conventional N/C Programming. The purpose of AUTOCON is to automatically generate a toolpath around the external profile of a PWB with no user intervention. The Process Engineer can generate a profile contour N/C tape after he has completed the panel layout and traveller through CAPPS for a part. After the layout and traveller illustrations have been completed, the same geometry can then be utilized again for the N/C tape. An N/C Analysist then reviews the listing for a final checkout of the job. 13 figs.
Dynamical Spacetimes from Numerical Hydrodynamics
Allan Adams; Nathan Benjamin; Arvin Moghaddam; Wojciech Musial
2014-11-07T23:59:59.000Z
We numerically construct dynamical asymptotically-AdS$_4$ metrics by evaluating the fluid/gravity metric on numerical solutions of dissipative hydrodynamics in (2+1) dimensions. The resulting numerical metrics satisfy Einstein's equations in (3+1) dimensions to high accuracy.
Numerical Analysis Gordon K. Smyth
Smyth, Gordon K.
Numerical Analysis 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 Analysis Numerical analysis is concerned with the accurate and efficient evalua- tion of mathematical expressions
Simulation of Radon Transport in Geothermal Reservoirs
Semprini, Lewis; Kruger, Paul
1983-12-15T23:59:59.000Z
Numerical simulation of radon transport is a useful adjunct in the study of radon as an in situ tracer of hydrodynamic and thermodynamic numerical model has been developed to assist in the interpretation of field experiments. The model simulates transient response of radon concentration in wellhead geofluid as a function of prevailing reservoir conditions. The radon simulation model has been used to simulate radon concentration response during production drawdown and two flowrate transient tests in vapor-dominated systems. Comparison of model simulation with experimental data from field tests provides insight in the analysis of reservoir phenomena such as propagation of boiling fronts, and estimates of reservoir properties of porosity and permeability thickness.
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.
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.
Altubayyeb, Abdulaziz Samir
2014-01-01T23:59:59.000Z
??The reserve growth potential of existing conventional oil reservoirs is huge. This research, through numerical simulation, aims to evaluate pattern size reduction as a strategy… (more)
Numerical Tests of the Improved Fermilab Action
C. Detar; A. S. Kronfeld; M. B. Oktay
2010-11-23T23:59:59.000Z
Recently, the Fermilab heavy-quark action was extended to include dimension-six and -seven operators in order to reduce the discretization errors. In this talk, we present results of the first numerical simulations with this action (the OK action), where we study the masses of the quarkonium and heavy-light systems. We calculate combinations of masses designed to test improvement and compare results obtained with the OK action to their counterparts obtained with the clover action. Our preliminary results show a clear improvement.
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.
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.
Numerical simulation of three-dimensional electrical flow through geomaterials
Akhtar, Anwar Saeed
1998-01-01T23:59:59.000Z
components in different arrangements (Mitchell 1993; Shang et al. 1995). These are very simple models and have been verified by experiments that consider only one-dimensional flow of current. In actual practice, current flow is three-dimensional around... the source. Methods do not exist to analyze three-dimensional current flow through circuit elements other than resistors. Thus, there is a need to develop methods to overcome these shortcomings. Electrical cone penetrometers have been used to convey...
Numerical simulation of cooling gas injection using adaptive multiscale techniques
for supersonic flows. Film cooling for supersonic flows is, for instance, considered in scramjet applications
Exact controllability of a piezoelectric body. Theory and numerical simulation
Sart, Remi
that a coupled elasticÂelectric control acting on the whole boundary of the body drives the system to rest after made of a material whose constitutive law introduces an elasticity-electricity coupling. We show control alone. Key words: Piezo-electricity, Exact boundary controllability, Finite element approxima
Numerical Simulations of Compact Binaries Lawrence E. Kidder
Maryland at College Park, University of
, Mark Scheel, Bela Szilagyi, Kip Thorne CITA: Harald Pfeiffer Motivation: Gravitational waves Properties gauge source functions key to get common horizon [Lindblom, Szilagyi; arXiv:0904.4873 (2009)] Change
DNAPL remediation of fractured rock evaluated via numerical simulation
Pang, Ti Wee
2010-01-01T23:59:59.000Z
Fractured rock formations represent a valuable source of groundwater and can be highly susceptible to contamination by dense, non-aqueous phase liquids (DNAPLs). The goal of this research is to evaluate the effectiveness ...
Direct Numerical Simulation of the Flow in a Pebble Bed
Ward, Paul
2014-06-24T23:59:59.000Z
,lelt),uvdyms(lx1,ly1,lz1,lelt), $ uvdzms(lx1,ly1,lz1,lelt),uwdxms(lx1,ly1,lz1,lelt), $ uwdyms(lx1,ly1,lz1,lelt),uwdzms(lx1,ly1,lz1,lelt), $ vwdxms(lx1,ly1,lz1,lelt),vwdyms(lx1,ly1,lz1,lelt), $ vwdzms(lx1,ly1,lz1,lelt),eps_uu(lx1...,ly1,lz1,lelt), $ eps_vv(lx1,ly1,lz1,lelt),eps_ww(lx1,ly1,lz1,lelt), $ eps_uv(lx1,ly1,lz1,lelt),eps_uw(lx1,ly1,lz1,lelt), $ eps_vw(lx1,ly1,lz1,lelt) common /production/ $ prd_uu(lx1,ly1,lz1,lelt),prd_vv(lx1,ly1,lz1,lelt...
NUMERICAL SIMULATIONS OF A 2D QUASI GEOSTROPHIC EQUATION
Paris-Sud XI, UniversitÃ© de
, France, jean-paul.chehab@u-picardie.fr & INRIA Nord-Europe, SIMPAF Project, Villeuneuve d'Ascq, France and atmosphere at middle latitudes. Indeed, air that streams to the south is pushed east or west through Coriolis
Numerical Simulations of Leakage from Underground LPG Storage Caverns
Yamamoto, Hajime; Pruess, Karsten
2004-01-01T23:59:59.000Z
model contains three propane storage caverns, 10 m wide and3.2.9. The loss of propane from storage is not significant,liquefied propane) was placed in the storage caverns, and
Numerical Simulation in Applied Geophysics. From the Mesoscale to ...
santos
due to patchy brine-CO2 saturation .... Case 4: A brine saturated sample with a fractal frame and ..... foods, groundwater flow and contamination among others.
Numerical Simulation of Underground Solar Thermal Energy Storage.
Sweet, Marshall
2010-01-01T23:59:59.000Z
??The United States Department of Energy indicates that 97% of all homes in the US use fossil fuels either directly or indirectly for space heating.… (more)
Numerical simulation of two-phase fluid flow
2013-01-30T23:59:59.000Z
42c, 34010 Sgonico, Trieste, Italy. E-mail: jcarcione@inogs.it. 2 CONICET, Departamento de Geof?sica Aplicada, Fac. Ciencias Astronómicas y Geof?sicas,.
Direct Numerical Simulation of Unsteady Decelerating Flows Yongmann M. Chung
Chung, Yongmann M.
. In contrast, v' and w' do not decrease immediately and show a little delayed response after the pressu
A numerical simulation of slantwise convection: its structure and evolution
Overpeck, Scott Allen
2001-01-01T23:59:59.000Z
gained more acceptance as the cause of the rainbands under certain conditions. Bennetts and Hoskins (1979) predict that under saturated conditions, CSI would be released, forming slantwise roll circulations with sloping updrafts and downdrafts (slantwise...
Numerical simulations of supercell interactions with thermal boundaries
Kay, Michael Paul
1999-01-01T23:59:59.000Z
. Storm motion. . d. Storm structure at time of peak surface vertical vorticity. . . . . . 5. ANALYSIS OF THE ORIGINS OF LOW-LEVEL ROTATION. . . . . . . . a. Background. . b. Circulation analyses. . c. Theories for delayed mesocyclogenesis. d. Low...-level mesocyclone strength. e. -3 K circulation, 6. CONCLUSIONS. . Page v V1 V111 13 13 14 22 34 40 42 49 49 52 61 70 73 80 REFERENCES VITA, . Page 89 LIST OF FIGURES FIGURE Surface mesoanalysis for 6 May 1975. . . . . Surface analysis...
Direct numerical simulation of turbulent Taylor–Couette flow
2007-08-23T23:59:59.000Z
the flow is characterized by the radius ratio, ? = R1/R2, where R1 and R2 are the radii ... vortices at the critical onset Taylor number Tc (defined as the Taylor number at which ... Beyond 5 × 105Tc these turbulent vortices became fragmented and lost .... employ a stiffly stable velocity-correction-type scheme with a third-order ...
Numerical Simulations of Dynamos Generated in Spherical Couette Flows
Boyer, Edmond
at generating a self-sustained magnetic field. No dynamo action occurs for axisymmetric flow while we always, Forest et al., 2002). No self-sustained magnetic fields were observed in the parameter regime where of ferromagnetic impellers, a self-sustained magnetic field has been observed in the Von KÂ´armÂ´an Sodium (VKS
Numerical Simulation of Polymer Flow in Microfluidic Devices Bakytzhan Kallemov
in pharmaceuticals, continuous monitoring and diagnostics in biotechnology, and fuel cells in energy to design and optimize trust- worthy working devices, and to get them to market more quickly and with less
Radioluminescence in Al : C analytical and numerical simulation results
Chen, Reuven
a quantitative description of the thermoluminescence and optically stimulated luminescence processes in Al2O3 : C is also solved analytically by assuming dynamic balance during sample irradiation. Analytical expressions are obtained for the concentrations of traps and centres in the material during irradiation with short
Experimental and numerical simulation of dough kneading in filled geometries
Grant, P. W.
of the study is to be able to optimise mixer design, in terms of energy efficiency and the amount and type pictures of the model #12;mixer, under operation and a baked product as a result). However, the two main
Direct Numerical Simulation of Polymer Electrolyte Fuel Cell Catalyst
. Mukherjee,1 Guoqing Wang,2 and Chao-Yang Wang1 * 1 Electrochemical Engine Center (ECEC), and Department efficiency, zero pollution and low noise, are widely considered as the 21st century energy- conversion humidified air is fed into the cathode. Hydrogen and oxygen combine electrochemically within the active
Numerical Simulation of Compositional Fluid Flow in Porous Media
Ewing, Richard E.
variables is developed for modeling the enhanced oil recovery pro- cesses. A mixed #12;nite element method to predict the reservoir performance under various exploita- tion schemes. In many enhanced oil recovery. Computational results for two- and three-phase multi-component uid ow occurring in enhanced oil re- covery
DIRECT NUMERICAL SIMULATION OF HOT AND HIGHLY PULSATED
Sart, Remi
generated by direct current plasma torch. Plasma spraying is used to deposit thick coatings on a substrate, turbulence, compact scheme, non-reflecting bound- ary conditions 1 Introduction Plasma spraying and transport properties are evaluated by using tabulated values for the viscosity and the thermal conductivity
Direct Numerical Simulations of Plunging Airfoils Yves Allaneau
Jameson, Antony
Energy H Specific Total Enthalpy k Specific Kinetic Energy Dynamic Viscosity Volume Viscosity) scheme, the global balance of kinetic energy over the computational domain, along with the balance of mass, momentum and total energy is respected. The KEP scheme provides improved stability, removing
Course: Numerical Simulation in Applied Geophysics. From the ...
2013-10-09T23:59:59.000Z
Technip, Paris, (1987). [6] S. C. Brenner and L. R. Scott, The Mathematical Theory of Finite Element. Methods, Springer, New York, 1994. [7] P. G. Ciarlet, The ...
Numerical Simulation in Applied Geophysics. From de Messocale to ...
2013-10-09T23:59:59.000Z
Editions Technip, Paris, (1987). [7] S. C. Brenner and L. R. Scott, The Mathematical Theory of Finite Ele- ment Methods, Springer, New York, 1994. [8] P. G. ...
Numerical Simulation in Applied Geophysics. From the Mesoscale to ...
Instituto del Gas y del Petróleo, Facultad de Ingenie? a UBA ... Seismic wave propagation is a common technique used in hydrocarbon exploration geophysics
advanced numerical simulations: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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....
advanced numerical simulation: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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....
Physical formulation and numerical algorithm for simulating N ...
S. Dong
2014-12-15T23:59:59.000Z
Dec 5, 2014 ... Media 82 (2010) 463–483. .... [41] K.A. Smith, F.J. Solis, D.L. Chopp, A projection method for motion of triple juncations by level sets, Interfaces ...
NUMERICAL SIMULATIONS OF KATABATIC JUMPS IN COATS LAND, ANTARCTICA
Renfrew, Ian
supercritical to subcritical flow, in a hydraulic sense, i.e., the Froude number (Fr) of the flow changes from-Layer Meteorology (2005) 114: 413Â437 Ã? Springer 2005 #12;taining coastal open water areas (polynyas) (Bromwich, this corresponds to a change from supercritical (Froude number Fr > 1) to subcritical (Fr
Treatment of physical and numerical diffusion in fluid dynamic simulations
Huh, Kang Yul
1983-01-01T23:59:59.000Z
A computer code is developed to predict the behavior of the hydrogen gas in the containment aftet a loss-ofcoolant accident. The conservation equations for the four components, i.e., air, hydrogen, steam and water, are set ...
NUMERICAL SIMULATION OF RESERVOIR COMPACTION IN LIQUID DOMINATED GEOTHERMAL SYSTEMS
Lippmann, M.J.
2010-01-01T23:59:59.000Z
13. modeling of liquid geothermal systems: Ph.D. thesis,of water dominated geothermal fields with large temper~of land subsidence in geothermal areas: Proc. 2nd Int. Symp.
VERIFICATION OF A NUMERICAL SIMULATION TECHNIQUE FOR NATURAL CONVECTION
Gadgil, A.
2008-01-01T23:59:59.000Z
on advanced passive cooling techniques. Systems Analysis andand fabrica- tion techniques. Cooling Systems Research. This
Multi-Phase Flow: Direct Numerical Simulation Igor Bolotnov
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),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment SurfacesResource ProgramModification andinterface1JUN 2 5 2014Mud3-000 Multi-Phase
Direct Numerical Simulations and Robust Predictions of Cloud Cavitation
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),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to UserProduct: CrudeOfficeNERSCDiesel prices topDirectCollapse | Argonne
22nd International Conference on Numerical Simulation of Plasmas (ICNSP) |
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),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert SouthwestTechnologies |November 2011 Mon, Next2025 Power MarketingPrinceton Plasma
22nd International Conference on Numerical Simulation of Plasmas (ICNSP) |
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),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert SouthwestTechnologies |November 2011 Mon, Next2025 Power MarketingPrinceton
Tropical anvil cirrus evolution from observations and numerical simulations
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),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched Ferromagnetism in Layered NbS2TopoPortalBRDF EffectsPacific: A Year in
Sandia National Laboratories: Numerical Simulations of Hydrokinetics in the
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),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 -theErik Spoerke SSLSMolten-Salt StorageNo More GreenWorkshops NuclearandRoza Canal,
Sensor and numerical simulator evaluation for porous medium desiccation and
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),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administrationcontroller systemsBi (2) SrEvaluating theDepartmentSensitivity of Radiativerewetting
Nonlinear Gulf Stream Interaction with Deep Currents: A Numerical Simulation
Bowman, Malcolm
gasifying and escaping into the atmosphere, may oxidize and add huge amounts of CO2 (Katz et al., 1999 Ocean, Caribbean Sea and Gulf of Mexico region between 10 N and 73 N. All advection and horizontal and possible global climate warming. These rings transport heat northward in the wedge shaped region between
Assessment of Molecular Modeling & Simulation
None
2002-01-03T23:59:59.000Z
This report reviews the development and applications of molecular and materials modeling in Europe and Japan in comparison to those in the United States. Topics covered include computational quantum chemistry, molecular simulations by molecular dynamics and Monte Carlo methods, mesoscale modeling of material domains, molecular-structure/macroscale property correlations like QSARs and QSPRs, and related information technologies like informatics and special-purpose molecular-modeling computers. The panel's findings include the following: The United States leads this field in many scientific areas. However, Canada has particular strengths in DFT methods and homogeneous catalysis; Europe in heterogeneous catalysis, mesoscale, and materials modeling; and Japan in materials modeling and special-purpose computing. Major government-industry initiatives are underway in Europe and Japan, notably in multi-scale materials modeling and in development of chemistry-capable ab-initio molecular dynamics codes.
Numerical Modeling of HCCI Combustion
Broader source: Energy.gov (indexed) [DOE]
Numerical Modeling of HCCI Combustion Salvador M. Aceves, Daniel L. Flowers, J. Ray Smith, Joel Martinez-Frias, Francisco Espinosa-Loza, Tim Ross, Bruce Buchholz, Nick...
RELAP-7 Numerical Stabilization: Entropy Viscosity Method
R. A. Berry; M. O. Delchini; J. Ragusa
2014-06-01T23:59:59.000Z
The RELAP-7 code is the next generation nuclear reactor system safety analysis code being developed at the Idaho National Laboratory (INL). The code is based on the INL's modern scientific software development framework, MOOSE (Multi-Physics Object Oriented Simulation Environment). The overall design goal of RELAP-7 is to take advantage of the previous thirty years of advancements in computer architecture, software design, numerical integration methods, and physical models. The end result will be a reactor systems analysis capability that retains and improves upon RELAP5's capability and extends the analysis capability for all reactor system simulation scenarios. RELAP-7 utilizes a single phase and a novel seven-equation two-phase flow models as described in the RELAP-7 Theory Manual (INL/EXT-14-31366). The basic equation systems are hyperbolic, which generally require some type of stabilization (or artificial viscosity) to capture nonlinear discontinuities and to suppress advection-caused oscillations. This report documents one of the available options for this stabilization in RELAP-7 -- a new and novel approach known as the entropy viscosity method. Because the code is an ongoing development effort in which the physical sub models, numerics, and coding are evolving, so too must the specific details of the entropy viscosity stabilization method. Here the fundamentals of the method in their current state are presented.
Numerical modeling of magnetohydrodynamic activity in the Swarthmore Spheromak Experiment
Brown, Michael R.
Numerical modeling of magnetohydrodynamic activity in the Swarthmore Spheromak Experiment V. S resistive magnetohydrodynamic MHD simulation are compared to experimental data from the Swarthmore Spheromak is shown to reproduce global equilibrium magnetic field profiles of the spheromaks as well as much
A probabilistic numerical method for optimal multiple switching problem
performing the numerical resolution, the storage of the Monte Carlo simulation paths is not needed. Then, we at the minimum cost under a given constraint on the loss of load probability or on the level of energy non to thank Thomas Vareschi, Xavier Warin and the participants of the FiME seminar and the Energy Finance
Chimera: A hybrid approach to numerical loop quantum cosmology
Diener, Peter; Singh, Parampreet
2013-01-01T23:59:59.000Z
The existence of a quantum bounce in isotropic spacetimes is a key result in loop quantum cosmology (LQC), which has been demonstrated to arise in all the models studied so far. In most of the models, the bounce has been studied using numerical simulations involving states which are sharply peaked and which bounce at volumes much larger than the Planck volume. An important issue is to confirm the existence of the bounce for states which have a wide spread, or which bounce closer to the Planck volume. Numerical simulations with such states demand large computational domains, making them very expensive and practically infeasible with the techniques which have been implemented so far. To overcome these difficulties, we present an efficient hybrid numerical scheme using the property that at the small spacetime curvature, the quantum Hamiltonian constraint in LQC, which is a difference equation with uniform discretization in volume, can be approximated by a Wheeler-DeWitt differential equation. By carefully choosi...
Numerical analysis of nanostructures for enhanced light extraction from OLEDs
Zschiedrich, L; Burger, S; Schmidt, F; 10.1117/12.2001132
2013-01-01T23:59:59.000Z
Nanostructures, like periodic arrays of scatters or low-index gratings, are used to improve the light outcoupling from organic light-emitting diodes (OLED). In order to optimize geometrical and material properties of such structures, simulations of the outcoupling process are very helpful. The finite element method is best suited for an accurate discretization of the geometry and the singular-like field profile within the structured layer and the emitting layer. However, a finite element simulation of the overall OLED stack is often beyond available computer resources. The main focus of this paper is the simulation of a single dipole source embedded into a twofold infinitely periodic OLED structure. To overcome the numerical burden we apply the Floquet transform, so that the computational domain reduces to the unit cell. The relevant outcoupling data are then gained by inverse Flouqet transforming. This step requires a careful numerical treatment as reported in this paper.
Numerical Comparisons of Three Recently Proposed Algorithms in the Protein Folding Problem
Hansmann, Uwe H E; Hansmann, Ulrich H.E.; Okamoto, Yuko
1997-01-01T23:59:59.000Z
We compare numerically the effectiveness of three recently proposed algorithms, multicanonical simulations, simulations in a 1/k-ensemble, and simulated tempering for the protein folding problem. For this we perform simulations with high statistics for one of the simplest peptides, Met-enkephalin. While the performances of all three approaches is much better than traditional methods, we find that the differences among the three are only marginal.
On spurious behavior of CFD simulations
Yee, H.C. [National Aeronautics and Space Administration, Moffett Field, CA (United States). Ames Research Center; Torczynski, J.R. [Sandia National Labs., Albuquerque, NM (United States); Morton, S.A.; Visbal, M.R. [Wright Lab., Wright-Patterson AFB, OH (United States); Sweby, P.K. [Univ. of Reading (United Kingdom)
1997-05-01T23:59:59.000Z
Spurious behavior in underresolved grids and/or semi-implicit temporal discretizations for four computational fluid dynamics (CFD) simulations are studied. The numerical simulations consist of (a) a 1-D chemically relaxed nonequilibrium model, (b) the direct numerical simulation (DNS) of 2-D incompressible flow over a backward facing step, (c) a loosely-coupled approach for a 2-D fluid-structure interaction, and (d) a 3-D compressible unsteady flow simulation of vortex breakdown in delta wings. Using knowledge from dynamical systems theory, various types of spurious behaviors that are numerical artifacts were systematically identified. These studies revealed the various possible dangers of misinterpreting numerical simulation of realistic complex flows that are constrained by the available computing power. In large scale computations underresolved grids, semi-implicit procedures, loosely-coupled implicit procedures, and insufficiently long time integration in DNS are most often unavoidable. Consequently, care must be taken in both computation and in interpretation of the numerical data. The results presented confirm the important role that dynamical systems theory can play in the understanding of the nonlinear behavior of numerical algorithms and in aiding the identification of the sources of numerical uncertainties in CFD.
Comprehensive Modeling and Numerical Investigation of Entrained-Flow Coal Gasifiers.
Silaen, Armin
2010-01-01T23:59:59.000Z
??Numerical simulations of coal gasification process inside a generic 2-stage entrainedflow gasifier are carried out using the commercial CFD solver ANSYS/FLUENT. The 3-D Navier-Stokes equations… (more)
Numerical Analysis of Heat and Moisture Transfer in Underground Air-conditioning Systems
Wang, Q.; Miao, X.; Cheng, B.; Fan, L.
2006-01-01T23:59:59.000Z
In view of the influence of humidity of room air on room heat load, indoor environment and building energy consumption in underground intermittent air-conditioning systems, numerical simulation was used to dynamically analyze the coupling condition...
Modeling and numerics for two partial differential equation systems arising from nanoscale physics
Brinkman, Daniel
2013-04-30T23:59:59.000Z
), we study the operation of the device in several specific asymptotic regimes. Furthermore, we simulate such devices using a customized 2D hybrid discontinuous Galerkin finite element scheme and compare the numerical results to our asymptotics. Next, we...
Numerical and analytical studies of single and multiphase starting jets and plumes
Wang, Ruo-Qian
2014-01-01T23:59:59.000Z
Multiphase starting jets and plumes are widely observed in nature and engineering systems. An environmental engineering example is open-water disposal of sediments. The present study numerically simulates such starting ...
Benjamin Aylott; John G. Baker; William D. Boggs; Michael Boyle; Patrick R. Brady; Duncan A. Brown; Bernd Brügmann; Luisa T. Buchman; Alessandra Buonanno; Laura Cadonati; Jordan Camp; Manuela Campanelli; Joan Centrella; Shourov Chatterji; Nelson Christensen; Tony Chu; Peter Diener; Nils Dorband; Zachariah B. Etienne; Joshua Faber; Stephen Fairhurst; Benjamin Farr; Sebastian Fischetti; Gianluca Guidi; Lisa M. Goggin; Mark Hannam; Frank Herrmann; Ian Hinder; Sascha Husa; Vicky Kalogera; Drew Keppel; Lawrence E. Kidder; Bernard J. Kelly; Badri Krishnan; Pablo Laguna; Carlos O. Lousto; Ilya Mandel; Pedro Marronetti; Richard Matzner; Sean T. McWilliams; Keith D. Matthews; R. Adam Mercer; Satyanarayan R. P. Mohapatra; Abdul H. Mroué; Hiroyuki Nakano; Evan Ochsner; Yi Pan; Larne Pekowsky; Harald P. Pfeiffer; Denis Pollney; Frans Pretorius; Vivien Raymond; Christian Reisswig; Luciano Rezzolla; Oliver Rinne; Craig Robinson; Christian Röver; Lucía Santamaría; Bangalore Sathyaprakash; Mark A. Scheel; Erik Schnetter; Jennifer Seiler; Stuart L. Shapiro; Deirdre Shoemaker; Ulrich Sperhake; Alexander Stroeer; Riccardo Sturani; Wolfgang Tichy; Yuk Tung Liu; Marc van der Sluys; James R. van Meter; Ruslan Vaulin; Alberto Vecchio; John Veitch; Andrea Viceré; John T. Whelan; Yosef Zlochower
2009-07-09T23:59:59.000Z
The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational-wave data analysis communities. The purpose of NINJA is to study the sensitivity of existing gravitational-wave search algorithms using numerically generated waveforms and to foster closer collaboration between the numerical relativity and data analysis communities. We describe the results of the first NINJA analysis which focused on gravitational waveforms from binary black hole coalescence. Ten numerical relativity groups contributed numerical data which were used to generate a set of gravitational-wave signals. These signals were injected into a simulated data set, designed to mimic the response of the Initial LIGO and Virgo gravitational-wave detectors. Nine groups analysed this data using search and parameter-estimation pipelines. Matched filter algorithms, un-modelled-burst searches and Bayesian parameter-estimation and model-selection algorithms were applied to the data. We report the efficiency of these search methods in detecting the numerical waveforms and measuring their parameters. We describe preliminary comparisons between the different search methods and suggest improvements for future NINJA analyses.