Sample records for flow simulation assisted

  1. Simulation- Assisted Audit of an Air Conditioned Office Building

    E-Print Network [OSTI]

    Bertagnolio, S.; Lebrun, J.; Hannay, J.; Silva, C. A.

    , an equation-based building-HVAC simulation tool is used to assist the audit. Fuel and electricity consumption are then interpreted and significant energy saving opportunities are identified....

  2. Assembly flow simulation of a radar

    SciTech Connect (OSTI)

    Rutherford, W.C.; Biggs, P.M.

    1993-10-01T23:59:59.000Z

    A discrete event simulation model has been developed to predict the assembly flow time of a new radar product. The simulation was the key tool employed to identify flow constraints. The radar, production facility, and equipment complement were designed, arranged, and selected to provide the most manufacturable assembly possible. A goal was to reduce the assembly and testing cycle time from twenty-six weeks to six weeks. A computer software simulation package (SLAM II) was utilized as the foundation a for simulating the assembly flow time. FORTRAN subroutines were incorporated into the software to deal with unique flow circumstances that were not accommodated by the software. Detailed information relating to the assembly operations was provided by a team selected from the engineering, manufacturing management, inspection, and production assembly staff. The simulation verified that it would be possible to achieve the cycle time goal of six weeks. Equipment and manpower constraints were identified during the simulation process and adjusted as required to achieve the flow with a given monthly production requirement. The simulation is being maintained as a planning tool to be used to identify constraints in the event that monthly output is increased. ``What-if`` studies have been conducted to identify the cost of reducing constraints caused by increases in output requirement.

  3. Adaptive LES Methodology for Turbulent Flow Simulations

    SciTech Connect (OSTI)

    Oleg V. Vasilyev

    2008-06-12T23:59:59.000Z

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

  4. Atrioventricular blood flow simulation based on patient-specific data

    E-Print Network [OSTI]

    Sussman, Mark

    Atrioventricular blood flow simulation based on patient-specific data Viorel Mihalef1 , Dimitris blood flow in- side the heart, usable with geometric models of the heart from patient- specific data. The method is geared toward realistic simulation of blood flow, taking into account not only heart wall

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

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

    experts in turbulent- flow simulation, computational mathematics, and high-performance computing. Building upon previous ASCR workshops on exascale computing, participants...

  6. Direct numerical simulation of turbulent reacting flows

    SciTech Connect (OSTI)

    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.

  7. Tritium flow through a non-symmetrical source. Simulation of gas flow through an injection hole

    E-Print Network [OSTI]

    Sharipov, Felix

    Tritium flow through a non-symmetrical source. Simulation of gas flow through an injection hole of source in injection rarefaction parameter µ0 viscosity of tritium at T0 Pa s 2 #12;Ll = 5074.5 Lr = 5007

  8. Large-eddy simulation of multiphase flows in complex combustors

    E-Print Network [OSTI]

    Mahesh, Krishnan

    Large-eddy simulation of multiphase flows in complex combustors S. V. Apte1 , K. Mahesh2 , F. Ham1 to accurately predict reacting multi-phase flows in practical combustors involving complex physical phenomena-turbine combustor geometries to evaluate the predictions made for multiphase, turbulent flow. 1 Introduction

  9. Numerical simulation of electrokinetically driven micro flows

    E-Print Network [OSTI]

    Hahm, Jungyoon

    2005-11-01T23:59:59.000Z

    in a micro-channel is studied. External electric field, flow rate of pressure driven flow, and geometry in the micro-channel are manipulated to obtain the focusing point, which led to determination of the electrophoretic mobility and (relative...

  10. Classical noise assists the flow of quantum energy by `momentum rejuvenation'

    E-Print Network [OSTI]

    Ying Li; Filippo Caruso; Erik Gauger; Simon C. Benjamin

    2014-06-13T23:59:59.000Z

    An important challenge in quantum science is to fully understand the efficiency of energy flow in networks. Here we present a simple and intuitive explanation for the intriguing observation that optimally efficient networks are not purely quantum, but are assisted by some interaction with a `noisy' classical environment. By considering the system's dynamics in both the site-basis and the momentum-basis, we show that the effect of classical noise is to sustain a broad momentum distribution, countering the depletion of high mobility terms which occurs as energy exits from the network. This picture predicts that the optimal level of classical noise is reciprocally related to the linear dimension of the lattice; our numerical simulations verify this prediction to high accuracy for regular 1D and 2D networks over a range of sizes up to thousands of sites. This insight leads to the discovery that dramatic further improvements in performance occur when a driving field targets noise at the low mobility components.

  11. Extinction Characteristics of Catalyst-Assisted Combustion in a Stagnation-Point Flow Reactor

    E-Print Network [OSTI]

    Im, Hong G.

    -NOx combustion as would be the case in the gas turbine application. In a premixed combustion mode, increasedExtinction Characteristics of Catalyst-Assisted Combustion in a Stagnation-Point Flow Reactor of detailed surface and gas- phase chemical kinetic models. Parametric studies are con- ducted to investigate

  12. Direct Numerical Simulation of the Flow in a Pebble Bed

    E-Print Network [OSTI]

    Ward, Paul

    2014-06-24T23:59:59.000Z

    bed reactors: dust generation and scaling, proceedings of ICAPP 2012, Chicago, June 24–28, 2012 [3] A. Shams, F. Roelofs, EMJ. Komen, E. Baglietto, 2013. “Quasi-direct numerical simulation of a pebble bed configuration. Part I: Flow (velocity...

  13. Numerical simulation of flow separation control by oscillatory fluid injection 

    E-Print Network [OSTI]

    Resendiz Rosas, Celerino

    2005-08-29T23:59:59.000Z

    In this work, numerical simulations of flow separation control are performed. The sep-aration control technique studied is called 'synthetic jet actuation'. The developed code employs a cell centered finite volume scheme which handles viscous...

  14. Grid adaptation for functional outputs of compressible flow simulations

    E-Print Network [OSTI]

    Venditti, David Anthony, 1973-

    2002-01-01T23:59:59.000Z

    An error correction and grid adaptive method is presented for improving the accuracy of functional outputs of compressible flow simulations. The procedure is based on an adjoint formulation in which the estimated error in ...

  15. Two-dimensional AMR simulations of colliding flows

    E-Print Network [OSTI]

    Niklaus, Markus; Niemeyer, Jens C

    2009-01-01T23:59:59.000Z

    Colliding flows are a commonly used scenario for the formation of molecular clouds in numerical simulations. Due to the thermal instability of the warm neutral medium, turbulence is produced by cooling. We carry out a two-dimensional numerical study of such colliding flows in order to test whether statistical properties inferred from adaptive mesh refinement (AMR) simulations are robust with respect to the applied refinement criteria. We compare probability density functions of various quantities as well as the clump statistics and fractal dimension of the density fields in AMR simulations to a static-grid simulation. The static grid with 2048^2 cells matches the resolution of the most refined subgrids in the AMR simulations. The density statistics is reproduced fairly well by AMR. Refinement criteria based on the cooling time or the turbulence intensity appear to be superior to the standard technique of refinement by overdensity. Nevertheless, substantial differences in the flow structure become apparent. In...

  16. SIMULATING NON-DARCY FLOW THROUGH POROUS MEDIA USING SUNDANCE

    E-Print Network [OSTI]

    Kelley, C. T. "Tim"

    Abstract A non-Darcy partial differential equation (PDE) model for flow through porous media is presentedSIMULATING NON-DARCY FLOW THROUGH POROUS MEDIA USING SUNDANCE J. P. REESE1 , K. R. LONG2 , C. T media has been modeled using either the linear Darcy's law or some empirical nonlinear relationship

  17. Fluid Flow Simulation in Fractured Reservoirs

    E-Print Network [OSTI]

    Sarkar, Sudipta

    2002-01-01T23:59:59.000Z

    The purpose of this study is to analyze fluid flow in fractured reservoirs. In most petroleum reservoirs, particularly carbonate reservoirs and some tight sands, natural fractures play a critical role in controlling fluid ...

  18. Multiscale CFD simulations of entrained flow gasification

    E-Print Network [OSTI]

    Kumar, Mayank, Ph. D. Massachusetts Institute of Technology

    2011-01-01T23:59:59.000Z

    The design of entrained flow gasifiers and their operation has largely been an experience based enterprise. Most, if not all, industrial scale gasifiers were designed before it was practical to apply CFD models. Moreover, ...

  19. Mesoscale simulations of polymer dynamics in microchannel flows

    E-Print Network [OSTI]

    L. Cannavacciuolo; R. G. Winkler; G. Gompper

    2007-09-24T23:59:59.000Z

    The non-equilibrium structural and dynamical properties of flexible polymers confined in a square microchannel and exposed to a Poiseuille flow are investigated by mesoscale simulations. The chain length and the flow strength are systematically varied. Two transport regimes are identified, corresponding to weak and strong confinement. For strong confinement, the transport properties are independent of polymer length. The analysis of the long-time tumbling dynamics of short polymers yields non-periodic motion with a sublinear dependence on the flow strength. We find distinct differences for conformational as well as dynamical properties from results obtained for simple shear flow.

  20. Submarine landslide flows simulation through centrifuge modelling

    E-Print Network [OSTI]

    Gue, Chang Shin

    2012-05-08T23:59:59.000Z

    ......... 140   4.6.4   Series 4: Experiments at various g le vels with a large flow rate in the dry condition ........................................................................................ 148   4.7   Repeatability of the Centrifuge Experiments... .......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .188   5.5.4   Side wall friction ..................................................................................189   5.5.5   Basal friction and pore pressure ratio ( ? ) ............................................ 194   5.6   Summary...

  1. Integration of an Aggregate Flow Model with a Traffic Flow Simulator

    E-Print Network [OSTI]

    Integration of an Aggregate Flow Model with a Traffic Flow Simulator Robert Hoffman , Dengfeng Sun restrictions to aircraft movement are applied by air traffic controllers and traffic managers in response to demand overages or capacity shortfalls in sectors of airspace. To estimate and assess the efficiency

  2. Unstructured spectral element methods of simulation of turbulent flows

    SciTech Connect (OSTI)

    Henderson, R.D. [California Inst. of Technology, Pasadena, CA (United States)] [California Inst. of Technology, Pasadena, CA (United States); Karniadakis, G.E. [Brown Univ., Providence, RI (United States)] [Brown Univ., Providence, RI (United States)

    1995-12-01T23:59:59.000Z

    In this paper we present a spectral element-Fourier algorithm for simulating incompressible turbulent flows in complex geometries using unstructured quadrilateral meshes. To this end, we compare two different interface formulations for extending the conforming spectral element method in order to allow for surgical mesh refinement and still retain spectral accuracy: the Zanolli iterative procedure and variational patching based on auxiliary {open_quotes}mortar{close_quotes} functions. We present an interpretation of the original mortar element method as a patching scheme and develop direct and iterative solution techniques that make the method efficient for simulations of turbulent flows. The properties of the new method are analyzed in detail by studying the eigenspectra of the advection and diffusion operators. We then present numerical results that illustrate the flexibility as well as the exponential convergence of the new algorithm for nonconforming discretizations. We conclude with simulation studies of the turbulent cylinder wake at Re = 1000 (external flow) and turbulent flow over riblets at Re = 3280 (internal flow). 36 refs., 29 figs., 7 tabs.

  3. MPSalsa 3D Simulations of Chemically Reacting Flows

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Many important scientific and engineering applications require a detailed analysis of complex systems with coupled fluid flow, thermal energy transfer, mass transfer and nonequilibrium chemical reactions. Currently, computer simulations of these complex reacting flow problems are limited to idealized systems in one or two spatial dimensions when coupled with a detailed, fundamental chemistry model. The goal of our research is to develop, analyze and implement advanced MP numerical algorithms that will allow high resolution 3D simulations with an equal emphasis on fluid flow and chemical kinetics modeling. In our research, we focus on the development of new, fully coupled, implicit solution strategies that are based on robust MP iterative solution methods (copied from http://www.cs.sandia.gov/CRF/MPSalsa/). These simulations are needed for scientific and technical areas such as: combustion research for transportation, atmospheric chemistry modeling for pollution studies, chemically reacting flow models for analysis and control of manufacturing processes, surface catalytic reactors for methane to methanol conversion and chemical vapor deposition (CVD) process modeling for production of advanced semiconductor materials (http://www.cs.sandia.gov/CRF/MPSalsa/).

    This project website provides six QuickTime videos of these simulations, along with a small image gallery and slideshow animations. A list of related publications and conference presentations is also made available.

  4. Simulation of salt migrations in density dependent groundwater flow

    E-Print Network [OSTI]

    Vuik, Kees

    Simulation of salt migrations in density dependent groundwater flow E.S. van Baaren Master's Thesis for the salt migration in the groundwater underneath the polders near the coast. The problem description of this thesis is to investigate the possibilities of modelling salt migrations in density dependent groundwater

  5. Computer simulation of flow past superhydrophobic striped surfaces

    E-Print Network [OSTI]

    Zhou, Jiajia

    Computer simulation of flow past superhydrophobic striped surfaces Jiajia Zhou1 , Aleksey V of superhydrophobic surfaces. 1 Introduction Fluid modeling from micrometer to nanometer scale not only that patterned superhydrophobic materials are important in context of fluid dynamics and their superlubricating

  6. Parallel Multiphysics Simulations of Charged Particles in Microfluidic Flows

    E-Print Network [OSTI]

    Bartuschat, Dominik

    2014-01-01T23:59:59.000Z

    The article describes parallel multiphysics simulations of charged particles in microfluidic flows with the waLBerla framework. To this end, three physical effects are coupled: rigid body dynamics, fluid flow modelled by a lattice Boltzmann algorithm, and electric potentials represented by a finite volume discretisation. For solving the finite volume discretisation for the electrostatic forces, a cell-centered multigrid algorithm is developed that conforms to the lattice Boltzmann meshes and the parallel communication structure of waLBerla. The new functionality is validated with suitable benchmark scenarios. Additionally, the parallel scaling and the numerical efficiency of the algorithms are analysed on an advanced supercomputer.

  7. Computer Simulation of Reservoir Depletion and Oil Flow from the Macondo Well Following the Deepwater

    E-Print Network [OSTI]

    Computer Simulation of Reservoir Depletion and Oil Flow from the Macondo Well Following, 2010, Computer simulation of reservoir depletion and oil flow from the Macondo well following......................................................................................................................................... 7 Reservoir Depletion

  8. Numerical simulation of water flow around a rigid fishing net

    E-Print Network [OSTI]

    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.

  9. Simulations of ductile flow in brittle material processing

    SciTech Connect (OSTI)

    Luh, M.H.; Strenkowski, J.S.

    1988-12-01T23:59:59.000Z

    Research is continuing on the effects of thermal properties of the cutting tool and workpiece on the overall temperature distribution. Using an Eulerian finite element model, diamond and steel tools cutting aluminum have been simulated at various, speeds, and depths of cut. The relative magnitude of the thermal conductivity of the tool and the workpiece is believed to be a primary factor in the resulting temperature distribution in the workpiece. This effect is demonstrated in the change of maximum surface temperatures for diamond on aluminum vs. steel on aluminum. As a preliminary step toward the study of ductile flow in brittle materials, the relative thermal conductivities of diamond on polycarbonate is simulated. In this case, the maximum temperature shifts from the rake face of the tool to the surface of the machined workpiece, thus promoting ductile flow in the workpiece surface.

  10. A Study of mixing in computer simulated laminar flow systems 

    E-Print Network [OSTI]

    McFarland, Allison Anne

    1984-01-01T23:59:59.000Z

    1984 Major Subject: Chemical Engineering A STUDY OF MIXING IN COMPUTER SIMULATED LAMINAR FLOW SYSTEMS A Thesis by ALLISON ANNE MCFARLAND Approved as to style and content by: Gary B. Tatterson (Chairman) ries J. Glover (Member) A. Ted Watson...: Dr. Gary B. Tatterson Mixing is a process that reduces nonuniformities or gradients in composition, properties, or temperature of material in bulk. It is a basic part of many chemical engineering processes, yet the theoretical understanding...

  11. Implicit Large Eddy Simulation of Cavitation in Micro Channel Flows

    E-Print Network [OSTI]

    Hickel, S; Schmidt, S J

    2014-01-01T23:59:59.000Z

    We present a numerical method for Large Eddy Simulations (LES) of compressible two-phase flows. The method is validated for the flow in a micro channel with a step-like restriction. This setup is representative for typical cavitating multi-phase flows in fuel injectors and follows an experimental study of Iben et al., 2010. While a diesel-like test fuel was used in the experiment, we solve the compressible Navier-Stokes equations with a barotropic equation of state for water and vapor and a simple phase-change model based on equilibrium assumptions. Our LES resolve all wave dynamics in the compressible fluid and the turbulence production in shear layers.

  12. GPU accelerated simulations of bluff body flows using vortex particle methods

    E-Print Network [OSTI]

    Cottet, Georges-Henri

    GPU accelerated simulations of bluff body flows using vortex particle methods Diego Rossinelli in press as: D. Rossinelli et al., GPU accelerated simulations of bluff body flows using vortex particle Penalization Bluff body flows a b s t r a c t We present a GPU accelerated solver for simulations of bluff body

  13. Numerical Simulation of Bubble Formation in Co-Flowing Mercury

    SciTech Connect (OSTI)

    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.

  14. Heat transfer and material flow during laser assisted multi-layer additive manufacturing

    SciTech Connect (OSTI)

    Manvatkar, V.; De, A.; DebRoy, T. [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2014-09-28T23:59:59.000Z

    A three-dimensional, transient, heat transfer, and fluid flow model is developed for the laser assisted multilayer additive manufacturing process with coaxially fed austenitic stainless steel powder. Heat transfer between the laser beam and the powder particles is considered both during their flight between the nozzle and the growth surface and after they deposit on the surface. The geometry of the build layer obtained from independent experiments is compared with that obtained from the model. The spatial variation of melt geometry, cooling rate, and peak temperatures is examined in various layers. The computed cooling rates and solidification parameters are used to estimate the cell spacings and hardness in various layers of the structure. Good agreement is achieved between the computed geometry, cell spacings, and hardness with the corresponding independent experimental results.

  15. Simulation of High Density Pedestrian Flow: Microscopic Model

    E-Print Network [OSTI]

    Dridi, Mohamed H

    2015-01-01T23:59:59.000Z

    In recent years modelling crowd and evacuation dynamics has become very important, with increasing huge numbers of people gathering around the world for many reasons and events. The fact that our global population grows dramatically every year and the current public transport systems are able to transport large amounts of people, heightens the risk of crowd panic or crush. Pedestrian models are based on macroscopic or microscopic behaviour. In this paper, we are interested in developing models that can be used for evacuation control strategies. This model will be based on microscopic pedestrian simulation models, and its evolution and design requires a lot of information and data. The people stream will be simulated, based on mathematical models derived from empirical data about pedestrian flows. This model is developed from image data bases, so called empirical data, taken from a video camera or data obtained using human detectors. We consider the individuals as autonomous particles interacting through socia...

  16. Large-eddy simulation of swirling particle-laden flows in a coaxial-jet combustor

    E-Print Network [OSTI]

    Apte, Sourabh V.

    Large-eddy simulation of swirling particle-laden flows in a coaxial-jet combustor S.V. Apte a,* , K 2003 Abstract Large-eddy simulation (LES) of particle-laden, swirling flow in a coaxial-jet combustor;cyclone combustors, and biomass gasifiers (Lefebvre, 1989). The physics of such flows is extremely complex

  17. LATEX TikZposter Simulation of two-phase flow for

    E-Print Network [OSTI]

    Ábrahám, Erika

    below). Sunlight Fresnel Solar collector · Absorber tube (two-phase flow) · Secondary reflector · SolarLATEX TikZposter Simulation of two-phase flow for direct steam-generating solar thermal power Aachen University Simulation of two-phase flow for direct steam-generating solar thermal power plants

  18. Multiscale Simulation Framework for Coupled Fluid Flow and Mechanical Deformation

    SciTech Connect (OSTI)

    Tchelepi, Hamdi

    2014-11-14T23:59:59.000Z

    A multiscale linear-solver framework for the pressure equation associated with flow in highly heterogeneous porous formations was developed. The multiscale based approach is cast in a general algebraic form, which facilitates integration of the new scalable linear solver in existing flow simulators. The Algebraic Multiscale Solver (AMS) is employed as a preconditioner within a multi-stage strategy. The formulations investigated include the standard MultiScale Finite-Element (MSFE) andMultiScale Finite-Volume (MSFV) methods. The local-stage solvers include incomplete factorization and the so-called Correction Functions (CF) associated with the MSFV approach. Extensive testing of AMS, as an iterative linear solver, indicate excellent convergence rates and computational scalability. AMS compares favorably with advanced Algebraic MultiGrid (AMG) solvers for highly detailed three-dimensional heterogeneous models. Moreover, AMS is expected to be especially beneficial in solving time-dependent problems of coupled multiphase flow and transport in large-scale subsurface formations.

  19. An energy preserving formulation for the simulation of multiphase turbulent flows.

    E-Print Network [OSTI]

    Fuster, Daniel

    An energy preserving formulation for the simulation of multiphase turbulent flows. Abstract In this manuscript we propose an energy preserving formulation for the simulation of multiphase flows. The new jumps across the interface including surface tension effects. 1 Introduction Nowadays the simulation

  20. Hydrodynamical adaptive mesh refinement simulations of turbulent flows - II. Cosmological simulations of galaxy clusters

    E-Print Network [OSTI]

    L. Iapichino; J. C. Niemeyer

    2008-07-01T23:59:59.000Z

    The development of turbulent gas flows in the intra-cluster medium and in the core of a galaxy cluster is studied by means of adaptive mesh refinement (AMR) cosmological simulations. A series of six runs was performed, employing identical simulation parameters but different criteria for triggering the mesh refinement. In particular, two different AMR strategies were followed, based on the regional variability of control variables of the flow and on the overdensity of subclumps, respectively. We show that both approaches, albeit with different results, are useful to get an improved resolution of the turbulent flow in the ICM. The vorticity is used as a diagnostic for turbulence, showing that the turbulent flow is not highly volume-filling but has a large area-covering factor, in agreement with previous theoretical expectations. The measured turbulent velocity in the cluster core is larger than 200 km/s, and the level of turbulent pressure contribution to the cluster hydrostatic equilibrium is increased by using the improved AMR criteria.

  1. Numerical simulations of the Macondo well blowout reveal strong control of oil flow by reservoir permeability and exsolution of gas

    E-Print Network [OSTI]

    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

  2. Automation cueing modulates cerebral blood flow and vigilance in a simulated air traffic control task

    E-Print Network [OSTI]

    Parasuraman, Raja

    Automation cueing modulates cerebral blood flow and vigilance in a simulated air traffic control: Automation; vigilance; cerebral blood flow; mental workload; attentional resources. Automation cueing operator, depending on automation reliability. To assess these effects, transcranial Doppler sonography

  3. An unstructured finite volume simulator for multiphase flow through fractured-porous media

    E-Print Network [OSTI]

    Bajaj, Reena

    2009-01-01T23:59:59.000Z

    Modeling of multiphase flow in fractured media plays an integral role in management and performance prediction of oil and gas reserves. Geological characterization and nmultiphase flow simulations in fractured media are ...

  4. Simulation of Flow and Transport at the Micro (Pore) Scale

    SciTech Connect (OSTI)

    Trebotich, D; Miller, G H

    2007-04-05T23:59:59.000Z

    An important problem in porous media involves the ability of micron and submicron-sized biological particles such as viruses or bacteria to move in groundwater systems through geologic media characterized by rock or mixed gravel, clay and sand materials. Current simulation capabilities require properly upscaled (continuum) models of colloidal filtration and adsorption to augment existing theories of fluid flow and chemical transport. Practical models typically address flow and transport behavior in aquifers over distances of 1 to 10 km where, for example, fluid momentum balance is governed by the simple Darcy's Law as a function of a pressure gradient, elevation gradient and a medium-dependent permeability parameter. In addition to fluid advection, there are multiple transport processes occurring in these systems including diffusion, dispersion and chemical interactions with solids or other aqueous chemical species. Particle transport is typically modeled in the same way as dissolved species, except that additional loss terms are incorporated to model particle filtration (physical interception), adsorption (chemical interception) and inactivation. Proper resolution of these processes at the porous medium continuum scale constitutes an important closure problem in subsurface science. We present a new simulation capability based on enabling technologies developed for microfluidics applications to model transport of colloidal-sized particles at the microscale, with relevance to the pore scale in geophysical subsurface systems. Particulate is represented by a bead-rod polymer model and is fully-coupled to a Newtonian solvent described by Navier-Stokes. Finite differences are used to discretize the interior of the domain; a Cartesian grid embedded boundary/volume-of-fluid method is used near boundaries and interfaces. This approach to complex geometry is amenable to direct simulation on grids obtained from surface extractions of tomographic image data. Short-range interactions are included in the particle model. This capability has been previously demonstrated on polymer flow in spatially-resolved packed bed (3D) and post array (2D) systems. We also discuss the advantages of this approach for the development of high-resolution adaptive algorithms for multiscale continuum-particle and mesoscale coarse-grained molecular dynamics models.

  5. Pore-Scale Simulation Of Experimentally Realizable, Oscillatory Flow In Porous Rock

    E-Print Network [OSTI]

    Olson, John F.

    1999-01-01T23:59:59.000Z

    We report new simulations of oscillating flow in porous rock. Our goal is to better understand the frequency dependence of pore-scale fluid motion, which should ultimately

  6. Flume Studies of Sediment Transportation in Shallow Flow with Simulated Rainfall

    E-Print Network [OSTI]

    Nail, F.M.

    TR-2 1966 Flume Studies of Sediment Transportation in Shallow Flow with Simulated Rainfall F.M. Nail Texas Water Resources Institute Texas A&M University ...

  7. Tetrahedral hp finite elements: Algorithms and flow simulations

    SciTech Connect (OSTI)

    Sherwin, S.J.; Karniadakis, G.E. [Brown Univ., Providence RI (United States)] [Brown Univ., Providence RI (United States)

    1996-03-01T23:59:59.000Z

    We present a new discretisation for the incompressible Navier-Stokes equations that extends spectral methods to three-dimensional complex domains consisting of tetrahedral subdomains. The algorithm is based on standard concepts of hp finite elements as well as tensorial spectral elements. This new formulation employs a hierarchical/modal basis constructed from a new apex co-ordinate system which retains a generalised tensor product. These properties enable the development of computationally efficienct algorithms for use on standard finite volume unstructed meshes. A detailed analysis is presented that documents the stability and exponential convergence of the method and several flow cases are simulated and compared with analytical and experimental results. 34 refs., 28 figs., 1 tab.

  8. Modeling fluid flow through single fracture using experimental, stochastic, and simulation approaches

    E-Print Network [OSTI]

    Alfred, Dicman

    2004-09-30T23:59:59.000Z

    This research presents an approach to accurately simulate flow experiments through a fractured core using experimental, stochastic, and simulation techniques. Very often, a fracture is assumed as a set of smooth parallel plates separated by a...

  9. GPU accelerated flow solver for direct numerical simulation of turbulent flows

    SciTech Connect (OSTI)

    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.

  10. Simulation of Biological Flow and Transport in Complex Geometries using Embedded Boundary /

    E-Print Network [OSTI]

    Simulation of Biological Flow and Transport in Complex Geometries using Embedded Boundary / Volume for modeling polymer fluids in irregular microscale geometries that enables long-time simulation of validation the constitutive behavior of polymer fluids. Complex flow environment geometries are represented on Cartesian grids

  11. Comparison of Numerical Techniques Used for Simulating Variable-Density Flow and Transport Experiments

    E-Print Network [OSTI]

    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

  12. Friction dependence of shallow granular flows from discrete par-ticle simulations

    E-Print Network [OSTI]

    Al Hanbali, Ahmad

    Friction dependence of shallow granular flows from discrete par- ticle simulations Anthony Thornton relation for the macroscopic bed friction or basal roughness obtained from micro-scale discrete particle simulations of steady flows. We systematically vary the bed friction by changing the contact friction

  13. Numerical simulation of single-phase and multiphase non-Darcy flow in porous and fractured reservoirs

    E-Print Network [OSTI]

    Wu, Yu-Shu

    2000-01-01T23:59:59.000Z

    flow simulations in fractured reservoirs, Report LBL-15227,behavior of naturally fractured reservoirs, Soc. Pet. Eng.Flow in Porous and Fractured Reservoirs Yu-Shu Wu Earth

  14. Drop breakup in the flow through fixed beds via stochastic simulation in model Gaussian fields

    E-Print Network [OSTI]

    Shaqfeh, Eric

    Drop breakup in the flow through fixed beds via stochastic simulation in model Gaussian fields that the flow through a dilute disordered fixed bed of fibers produces large polymer conformation change beyond on the shape and breakup of viscous drops. Because the flow through a dilute fixed bed is equivalent

  15. Experimental validation of large eddy simulations of flow and heat transfer in a stationary ribbed duct

    E-Print Network [OSTI]

    Thole, Karen A.

    Elsevier Inc. All rights reserved. Keywords: Duct flow; Ribbed channels; LES 1. Introduction In an effortExperimental validation of large eddy simulations of flow and heat transfer in a stationary ribbed Abstract Accurate prediction of ribbed duct flow and heat transfer is of importance to the gas turbine

  16. Numeric Simulation of Heat Transfer and Electrokinetic Flow in an Electroosmosis-Based

    E-Print Network [OSTI]

    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

  17. Steam generators two phase flows numerical simulation with liquid and gas momentum equations

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    . The secondary flow is another loop that links the steam generator and the turbines. Inside the exchangerSteam generators two phase flows numerical simulation with liquid and gas momentum equations M Abstract This work takes place in steam generators flow studies and we consider here steady state three

  18. Simulating Vibrational Energy Flow in Proteins: Relaxation Rate and Mechanism for Heme Cooling in Cytochrome c

    E-Print Network [OSTI]

    Straub, John E.

    Simulating Vibrational Energy Flow in Proteins: Relaxation Rate and Mechanism for Heme Cooling dynamics simulation. The kinetic energy relaxation was found to be a biphasic exponential decay process in the heme protein myoglobin. Computer simulation of vibrational energy relaxation in heme proteins began

  19. Bluff Body Flow Simulation Using a Vortex Element Method

    SciTech Connect (OSTI)

    Anthony Leonard; Phillippe Chatelain; Michael Rebel

    2004-09-30T23:59:59.000Z

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

  20. Numerical simulation of three-dimensional electrical flow through geomaterials

    E-Print Network [OSTI]

    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...

  1. Numerical simulation of two-phase fluid flow

    E-Print Network [OSTI]

    2013-01-30T23:59:59.000Z

    diffusive wave (see also Carcione, 2007). Hence, fluid flow and pressure diffusion are phenomena described by the same differential equation. In hydrology and ...

  2. GMINC - A MESH GENERATOR FOR FLOW SIMULATIONS IN FRACTURED RESERVOIRS

    E-Print Network [OSTI]

    Pruess, K.

    2010-01-01T23:59:59.000Z

    Flow in Naturally Fractured Reservoirs, Society of Petroleumfor Naturally Fractured Reservoirs, paper SPE-11688,Determining Naturally Fractured Reservoir Properties by Well

  3. High Fidelity Simulation of Complex Suspension Flow for Practical...

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

    rheometer and mixing geometries to fundamental rheological properties, like viscosity versus strain rate, by studying the flow of concrete in such rheometers and by the...

  4. ON THE SIMULATION OF MULTICOMPONENT GAS FLOW IN POROUS MEDIA

    E-Print Network [OSTI]

    Ewing, Richard E.

    quadrilaterals as a solver to the non­Darcy flow equation, and a conservative Godunov­type scheme for the mass. Traditionally, the standard Darcy equation provides this relation. In this paper, however, we replace this classical law with the Forchheimer equation to model non­Darcy flow [9, 17, 13]. The mathematical nature

  5. Large-Eddy Simulation of Flow and Pollutant Transport in Urban Street Canyons with Ground Heating

    E-Print Network [OSTI]

    Li, Xian-Xiang

    Our study employed large-eddy simulation (LES) based on a one-equation subgrid-scale model to investigate the flow field and pollutant dispersion characteristics inside urban street canyons. Unstable thermal stratification ...

  6. Calculation of unsteady turbulent flow around obstacles using the large eddy simulation turbulence model

    E-Print Network [OSTI]

    Helton, Donald McLean

    2002-01-01T23:59:59.000Z

    The premise of the work presented here is to use a common analytical tool, Computational Fluid Dynamics (CFD), along with a prevalent turbulence model, Large Eddy Simulation (LES), to study the flow past rectangular cylinders. In an attempt to use...

  7. Simulation and visualization of fields and energy flows in electric circuits with idealized geometries

    E-Print Network [OSTI]

    Ohannessian, Mesrob I., 1981-

    2005-01-01T23:59:59.000Z

    This thesis develops a method to simulate and visualize the fields and energy flows in electric circuits, using a simplified physical model based on an idealized geometry. The physical models combine and extend previously ...

  8. Parallel Computing for the Simulation of 3D Free Surface Flows in Environmental Applications

    E-Print Network [OSTI]

    Causin, Paola

    Causin and Edie Miglio MOX - Modeling and Scientific Computing, Dipartimento di Matematica "F.Miglio@mate.polimi.it, WWW home page: http://www.mox.polimi.it Abstract. The numerical simulation of 3D free surface flows

  9. Groundwater flow with energy transport and waterice phase change: Numerical simulations, benchmarks, and application to

    E-Print Network [OSTI]

    McKenzie, Jeffrey M.

    saturated, coupled porewater-energy transport, with freezing and melting porewater, and includes propor transport; Freezing; Cold regions; Benchmark; Modelling 1. Introduction The freezing and thawingGroundwater flow with energy transport and water­ice phase change: Numerical simulations

  10. Comparison and Validation of Compressible Flow Simulations of Laser-Induced Cavitation

    E-Print Network [OSTI]

    Comparison and Validation of Compressible Flow Simulations of Laser-Induced Cavitation Bubbles)). The validation is performed for the case of laser-induced cavitation bubbles collapsing in an infinite medium

  11. Molecular dynamics simulations of oscillatory Couette flows with slip boundary conditions

    E-Print Network [OSTI]

    Priezjev, Nikolai V

    2012-01-01T23:59:59.000Z

    The effect of interfacial slip on steady-state and time-periodic flows of monatomic liquids is investigated using non-equilibrium molecular dynamics simulations. The fluid phase is confined between atomically smooth rigid walls, and the fluid flows are induced by moving one of the walls. In steady shear flows, the slip length increases almost linearly with shear rate. We found that the velocity profiles in oscillatory flows are well described by the Stokes flow solution with the slip length that depends on the local shear rate. Interestingly, the rate dependence of the slip length obtained in steady shear flows is recovered when the slip length in oscillatory flows is plotted as a function of the local shear rate magnitude. For both types of flows, the friction coefficient at the liquid-solid interface correlates well with the structure of the first fluid layer near the solid wall.

  12. Molecular dynamics simulations of oscillatory Couette flows with slip boundary conditions

    E-Print Network [OSTI]

    Nikolai V. Priezjev

    2012-08-27T23:59:59.000Z

    The effect of interfacial slip on steady-state and time-periodic flows of monatomic liquids is investigated using non-equilibrium molecular dynamics simulations. The fluid phase is confined between atomically smooth rigid walls, and the fluid flows are induced by moving one of the walls. In steady shear flows, the slip length increases almost linearly with shear rate. We found that the velocity profiles in oscillatory flows are well described by the Stokes flow solution with the slip length that depends on the local shear rate. Interestingly, the rate dependence of the slip length obtained in steady shear flows is recovered when the slip length in oscillatory flows is plotted as a function of the local shear rate magnitude. For both types of flows, the friction coefficient at the liquid-solid interface correlates well with the structure of the first fluid layer near the solid wall.

  13. Stochastic numerical simulations of long term unsaturated flow in waste rock piles

    E-Print Network [OSTI]

    Aubertin, Michel

    Stochastic numerical simulations of long term unsaturated flow in waste rock piles O. Fala Genivar water flow in waste rock piles using selected realizations of stochastically distributed hydraulic term hydrogeological behaviour of waste rock piles, to help select the construction sequence

  14. Simple Models of Zero-Net Mass-Flux Jets for Flow Control Simulations

    E-Print Network [OSTI]

    Mittal, Rajat

    Simple Models of Zero-Net Mass-Flux Jets for Flow Control Simulations Reni Raju Dynaflow Inc for modeling the dynamics of zero- net mass-flux (ZNMF) actuators, the computational costs associated-flow model. 1. INTRODUCTION Zero-net mass-flux (ZNMF) actuators or "synthetic jets" have potential

  15. Low level jet development during a numerically simulated return flow event

    E-Print Network [OSTI]

    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...

  16. Simulation of Nondifferentiable Models for Groundwater Flow and C. T. Kelleya

    E-Print Network [OSTI]

    1 Simulation of Nondifferentiable Models for Groundwater Flow and Transport C. T. Kelleya K. R frequently in models for groundwater flow and species transport. The van Genuchten and Mualem PSK relations. INTRODUCTION Nonsmooth, even non-Lipschitz continuous, constitutive laws are not uncommon in models

  17. Recent Advances in Computational Techniques for Simulation of Flow in Porous Media

    E-Print Network [OSTI]

    Coutinho, Alvaro L. G. A.

    are also addressed. Introduction Modeling porous media flow processes is required in many science and engineering applications. Oil recovery, environmental hydrology and groundwater flow are a few drivers in the development of porous media simulation tools. Nowadays high resolution models are constructed as a result

  18. aerodynamic flow simulation: Topics by E-print Network

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

    mueller (Siegfried Muller). 12;1 Introduction The investigation of cavitation bubbles is of interest for different 408 An experimental and simulation study...

  19. Sediment Transport in Shallow Subcritical Flow Disturbed by Simulated Rainfall 

    E-Print Network [OSTI]

    Machemehl, J. L.

    1968-01-01T23:59:59.000Z

    sediment samples were siphoned from the flow with a stainless steel-pipette sediment sampler. Sediment concentrations were found with a filtering technique. Sediment samples were taken with and without rainfall to evaluate the relative effect...

  20. Edge-based Meshless Methods for Compressible Flow Simulations

    E-Print Network [OSTI]

    Jameson, Antony

    are obtained for airfoils in transonic flow. Lift and drag coefficients also compare well to the finite volume, including (1) the application of certain artificial diffusion schemes to meshless methods within an edge

  1. Simulation of Combustion and Thermal Flow in an Industrial Boiler

    E-Print Network [OSTI]

    Saripalli, R.; Wang, T.; Day, B.

    2005-01-01T23:59:59.000Z

    insight into the detailed thermal-flow and combustion in the boiler and showing possible reasons for superheater tube rupture. The exhaust gas temperature is consistent with the actual results from the infrared thermograph inspection....

  2. Simulated Surface-Induced Thrombin Generation in a Flow Field

    E-Print Network [OSTI]

    Jordan, S.W.

    A computational model of blood coagulation is presented with particular emphasis on the regulatory effects of blood flow, spatial distribution of tissue factor (TF), and the importance of the thrombomodulin-activated protein ...

  3. Numerical simulation of three-dimensional electrical flow through geomaterials 

    E-Print Network [OSTI]

    Akhtar, Anwar Saeed

    1998-01-01T23:59:59.000Z

    95 99 V ELECTRICAL FLOW AROUND AN ELECTRICAL CONE PENETROMETER 104 5. 1 INTRODUCTION 5. 2 ANALYTICAL SOLUTION FOR ELECTRICAL FLOW AROUND AN ELECTRICAL CONE PENETROMETER 5. 3 NUMERICAL INVESTIGATION 5. 4 COMPARISON OF ANALYTICAL AND NUMERICAL... RESULTS 5. 5 CONCLUSION AND APPLICATION 5. 5. 1 Utilization of Numerical Results 104 106 110 113 115 116 VI EXPERIMENTAL EQUIPMENT DESIGN 121 6. 1 INTRODUCTION 6. 2 ELECTRICAL POWER SOURCE 6. 3 ELECTRICAL RESISTIVITY CONE PENETROMETER 6. 4...

  4. NUMERICAL SIMULATIONS OF LONG TERM UNSATURATED FLOW AND ACID MINE DRAINAGE AT WASTE ROCK PILES

    E-Print Network [OSTI]

    Aubertin, Michel

    NUMERICAL SIMULATIONS OF LONG TERM UNSATURATED FLOW AND ACID MINE DRAINAGE AT WASTE ROCK PILES Omar representative) waste rock piles and using observed climatic recharge data. The simulations were used to help are applied each year at the top of the piles, the water content profiles become periodic after a few years

  5. On the Modeling and Simulation of Non-Hydrostatic Dam Break Flows

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    by the failure of the dam structure. The determination of the potential consequences of a dam break requiresOn the Modeling and Simulation of Non-Hydrostatic Dam Break Flows Alexandre Caboussat S´ebastien Boyaval Alexandre Masserey January 1, 2013 Abstract The numerical simulation of three-dimensional dam

  6. Level Set Based Simulations of Two-Phase Oil-Water Flows in Pipes

    E-Print Network [OSTI]

    Soatto, Stefano

    the assumption that the densities of the two uids are di#11;erent and that the viscosity of the oil core is veryLevel Set Based Simulations of Two-Phase Oil-Water Flows in Pipes Hyeseon Shim July 31, 2000 Abstract We simulate the axisymmetric pipeline transportation of oil and water numerically under

  7. Hull/Mooring/Riser coupled motion simulations of thruster-assisted moored platforms 

    E-Print Network [OSTI]

    Ryu, Sangsoo

    2005-02-17T23:59:59.000Z

    To reduce large motion responses of moored platforms in a harsh environment in deep waters, a thruster-assisted position mooring system can be applied. By applying the system, global dynamic responses can be improved in ...

  8. Probabilistic Power Flow Simulation allowing Temporary Current Overloading

    E-Print Network [OSTI]

    Frank, Jason

    flow model subject to connection temperature constraints. Renewable power generation is included model. This substantially influences the choice of model for the renewable power source, as we explain realistically. Using such a constraint is justified the more by the intermittent nature of the renewable power

  9. FINITE ELEMENT METHODS FOR THE SIMULATION OF INCOMPRESSIBLE POWDER FLOW

    E-Print Network [OSTI]

    Hron, Jaroslav

    configurations are provided. PHYSICAL BACKGROUD 1. Mohr-Coulomb criterion for friction The Mohr theory suggests a frictional stress model must be taken into account. This can be done using plasticity and similar theories cannot accurately describe granular flow. It is assumed that the material is incompressible, dry

  10. Multiscale Modeling and Simulation of Fluid Flows in Inelastic Media

    E-Print Network [OSTI]

    Popov, Peter

    in porous media (e.g. soil), Elasticity equations in heterogeneous media (concrete, asphalt), etc porous media s The Fluid-Structure interaction (FSI) problem at the microscale and numerical methods with computational solutions s Numerical upscaling of flow in deformable porous media #12;- p. 3/42 Why homogenize

  11. A low diffusive Lagrange-remap scheme for the simulation of violent air-water free-surface flows.

    E-Print Network [OSTI]

    Boyer, Edmond

    . The evolution of the interfaces between phases and the consecutive complex dynamics need to be simulatedA low diffusive Lagrange-remap scheme for the simulation of violent air-water free-surface flows. Introduction Simulation of free surface flows knows an increasing interest as an essential predictive tool

  12. Dispersion of swimming algae in laminar and turbulent channel flows: theory and simulations

    E-Print Network [OSTI]

    Croze, O A; Ahmed, M; Bees, M A; Brandt, L

    2012-01-01T23:59:59.000Z

    Algal swimming is often biased by environmental cues, e.g. gravitational and viscous torques drive cells towards downwelling fluid (gyrotaxis). In view of biotechnological applications, it is important to understand how such biased swimming affects cell dispersion in a flow. Here, we study the dispersion of gyrotactic swimming algae in laminar and turbulent channel flows. By direct numerical simulation (DNS) of cell motion within upwelling and downwelling channel flows, we evaluate time-dependent measures of dispersion for increasing values of the flow Peclet (Reynolds) numbers, Pe (Re). Furthermore, we derive an analytical `swimming Taylor-Aris dispersion' theory, using flow-dependent transport parameters given by existing microscopic models. In the laminar regime, DNS results and analytical predictions compare very well, providing the first confirmation that cells' response to flow is best described by the generalized-Taylor-dispersion microscopic model. We predict that cells drift along a channel faster th...

  13. Mechanistic Foam Flow Simulation in Heterogeneous and Multidimensional Porous Media

    E-Print Network [OSTI]

    Patzek, Tadeusz W.

    -scale simulation is a vital component of the engineering and economic evaluation of any enhanced oil recovery (EOR Copyright 1997, Society of Petroleum Engineers, Inc. Received for review, April 24, 1997 Revised, July 23 generation, and foam propagation in rock formations. Efficient application and evaluation of candidates

  14. Simulation of heavy oil reservoir performance using a non-Newtonian flow model

    E-Print Network [OSTI]

    Narahara, Gene Masao

    1983-01-01T23:59:59.000Z

    . This reduction of viscosity as a function of shear rate has a significant effect on rates and other parameters when simulating reservoir performance. The objective of this study is to compare the simulation results of Newtonian and non-Newtonian oils under...)ected to increasing shear rate, the viscosity decreases. This behavior implies that the oil viscosity varies as a function of not only pressure, but also shear rate. This behavior is important when simulating heavy-oil reservoir performance. To simulate the flow...

  15. Programs for Laser-AO Assisted Integral-Field Spectrometers on Ionized Flows

    E-Print Network [OSTI]

    Cecil, Gerald

    (starburst galaxies) or by gas accretion (Herbig-Haro object [HHO] flows and AGN). I introduce some-Haro Outflows HHO's are second only to supernova remnants as laboratories for study of non- planar astrophysical shocks. Ionization is entirely local in HHO shocks. Because only the component of motion perpendicular

  16. Hydrodynamical adaptive mesh refinement simulations of turbulent flows - I. Substructure in a wind

    E-Print Network [OSTI]

    Iapichino, L; Schmidt, W; Niemeyer, J C

    2008-01-01T23:59:59.000Z

    The problem of the resolution of turbulent flows in adaptive mesh refinement (AMR) simulations is investigated by means of 3D hydrodynamical simulations in an idealised setup, representing a moving subcluster during a merger event. AMR simulations performed with the usual refinement criteria based on local gradients of selected variables do not properly resolve the production of turbulence downstream of the cluster. Therefore we apply novel AMR criteria which are optimised to follow the evolution of a turbulent flow. We demonstrate that these criteria provide a better resolution of the flow past the subcluster, allowing us to follow the onset of the shear instability, the evolution of the turbulent wake and the subsequent back-reaction on the subcluster core morphology. We discuss some implications for the modelling of cluster cold fronts.

  17. Hydrodynamical adaptive mesh refinement simulations of turbulent flows - I. Substructure in a wind

    E-Print Network [OSTI]

    L. Iapichino; J. Adamek; W. Schmidt; J. C. Niemeyer

    2008-07-01T23:59:59.000Z

    The problem of the resolution of turbulent flows in adaptive mesh refinement (AMR) simulations is investigated by means of 3D hydrodynamical simulations in an idealised setup, representing a moving subcluster during a merger event. AMR simulations performed with the usual refinement criteria based on local gradients of selected variables do not properly resolve the production of turbulence downstream of the cluster. Therefore we apply novel AMR criteria which are optimised to follow the evolution of a turbulent flow. We demonstrate that these criteria provide a better resolution of the flow past the subcluster, allowing us to follow the onset of the shear instability, the evolution of the turbulent wake and the subsequent back-reaction on the subcluster core morphology. We discuss some implications for the modelling of cluster cold fronts.

  18. Sensitivity Analysis and Stochastic Simulations of Non-equilibrium Plasma Flow

    SciTech Connect (OSTI)

    Lin, Guang; Karniadakis, George E.

    2009-11-05T23:59:59.000Z

    We study parametric uncertainties involved in plasma flows and apply stochastic sensitivity analysis to rank the importance of all inputs to guide large-scale stochastic simulations. Specifically, we employ different gradient-based sensitivity methods, namely Morris, multi-element probabilistic collocation method (ME-PCM) on sparse grids, Quasi-Monte Carlo, and Monte Carlo methods. These approaches go beyond the standard ``One-At-a-Time" sensitivity analysis and provide a measure of the nonlinear interaction effects for the uncertain inputs. The objective is to perform systematic stochastic simulations of plasma flows treating only as {\\em stochastic processes} the inputs with the highest sensitivity index, hence reducing substantially the computational cost. Two plasma flow examples are presented to demonstrate the capability and efficiency of the stochastic sensitivity analysis. The first one is a two-fluid model in a shock tube while the second one is a one-fluid/two-temperature model in flow past a cylinder.

  19. Simulation of FCC riser flow with multiphase heat transfer and cracking reactions.

    SciTech Connect (OSTI)

    Chang, S. L.; Zhou, C. Q.; Energy Systems

    2003-08-01T23:59:59.000Z

    A validated Computational Fluid Dynamics (CFD) code ICRKFLO was developed for simulations of three-dimensional three-phase reacting flows in Fluid Catalytic Cracking (FCC) riser reactors. It calculates the product yields based on local flow properties by solving the fundamental conservation principles of mass, momentum, and energy for the flow properties associated with the gas, liquid, and solid phases. Unique phenomenological models and numerical techniques were developed specifically for the FCC flow simulation. The models include a spray vaporization model, a particle-solid interaction model, and an interfacial heat transfer model. The numerical techniques include a time-integral approach to overcome numerical stiffness problems in chemical kinetics rate calculations and a hybrid hydrodynamic-kinetic treatment to facilitate detailed kinetics calculations of cracking reactions. ICRKFLO has been validated with extensive test data from two pilot and one commercial FCC units. It is proven to be useful for advanced development of FCC riser reactors.

  20. Mesoscale flows in large aspect ratio simulations of turbulent compressible convection

    E-Print Network [OSTI]

    F. Rincon; F. Lignieres; M. Rieutord

    2006-11-28T23:59:59.000Z

    We present the results of a very large aspect ratio (42.6) numerical simulation of fully compressible turbulent convection in a polytropic atmosphere, and focus on the properties of large-scale flows. Mesoscale patterns dominate the turbulent energy spectrum. We show that these structures, which had already been observed in Boussinesq simulations by Cattaneo et al. (2001), have a genuine convective origin and do not result directly from collective interactions of the smaller scales of the flow, even though their growth is strongly affected by nonlinear transfers. If this result is relevant to the solar photosphere, it suggests that the dominant convective mode below the Sun's surface may be at mesoscales.

  1. Hull/Mooring/Riser coupled motion simulations of thruster-assisted moored platforms

    E-Print Network [OSTI]

    Ryu, Sangsoo

    2005-02-17T23:59:59.000Z

    responses. Investigation of the performance of thruster-assisted moored offshore platforms was conducted in terms of six-degree-of-freedom motions and mooring line/riser top tensions by means of a fully coupled hull/mooring/riser dynamic analysis program...

  2. Researchers at Lancaster University are using the supercomputing capability of the Hartree Centre to accurately simulate the flow of

    E-Print Network [OSTI]

    Zharkova, Valentina V.

    Centre is an industrial gateway to world- class high performance computing (HPC) and simulation to approximate the flow of oil. The benefits Using high performance computing, simulation and exploiting key

  3. Numerical simulation of laminar reacting flows with complex chemistry

    SciTech Connect (OSTI)

    Day, Marcus S.; Bell, John B.

    1999-12-01T23:59:59.000Z

    We present an adaptive algorithm for low Mach number reacting flows with complex chemistry. Our approach uses a form of the low Mach number equations that discretely conserves both mass and energy. The discretization methodology is based on a robust projection formulation that accommodates large density contrasts. The algorithm uses an operator-split treatment of stiff reaction terms and includes effects of differential diffusion. The basic computational approach is embedded in an adaptive projection framework that uses structured hierarchical grids with subcycling in time that preserves the discrete conservation properties of the underlying single-grid algorithm. We present numerical examples illustrating the performance of the method on both premixed and non-premixed flames.

  4. Free-surface flow simulations for discharge-based operation of hydraulic structure gates

    E-Print Network [OSTI]

    Erdbrink, C D; Sloot, P M A

    2014-01-01T23:59:59.000Z

    We combine non-hydrostatic flow simulations of the free surface with a discharge model based on elementary gate flow equations for decision support in operation of hydraulic structure gates. A water level-based gate control used in most of today's general practice does not take into account the fact that gate operation scenarios producing similar total discharged volumes and similar water levels may have different local flow characteristics. Accurate and timely prediction of local flow conditions around hydraulic gates is important for several aspects of structure management: ecology, scour, flow-induced gate vibrations and waterway navigation. The modelling approach is described and tested for a multi-gate sluice structure regulating discharge from a river to the sea. The number of opened gates is varied and the discharge is stabilized with automated control by varying gate openings. The free-surface model was validated for discharge showing a correlation coefficient of 0.994 compared to experimental data. A...

  5. Closures for Course-Grid Simulation of Fluidized Gas-Particle Flows

    SciTech Connect (OSTI)

    Sankaran Sundaresan

    2010-02-14T23:59:59.000Z

    Gas-particle flows in fluidized beds and riser reactors are inherently unstable, and they manifest fluctuations over a wide range of length and time scales. Two-fluid models for such flows reveal unstable modes whose length scale is as small as ten particle diameters. Yet, because of limited computational resources, gas-particle flows in large fluidized beds are invariably simulated by solving discretized versions of the two-fluid model equations over a coarse spatial grid. Such coarse-grid simulations do not resolve the small-scale spatial structures which are known to affect the macroscale flow structures both qualitatively and quantitatively. Thus there is a need to develop filtered two-fluid models which are suitable for coarse-grid simulations and capturing the effect of the small-scale structures through closures in terms of the filtered variables. The overall objective of the project is to develop validated closures for filtered two-fluid models for gas-particle flows, with the transport gasifier as a primary, motivating example. In this project, highly resolved three-dimensional simulations of a kinetic theory based two-fluid model for gas-particle flows have been performed and the statistical information on structures in the 100-1000 particle diameters length scale has been extracted. Based on these results, closures for filtered two-fluid models have been constructed. The filtered model equations and closures have been validated against experimental data and the results obtained in highly resolved simulations of gas-particle flows. The proposed project enables more accurate simulations of not only the transport gasifier, but also many other non-reacting and reacting gas-particle flows in a variety of chemical reactors. The results of this study are in the form of closures which can readily be incorporated into existing multi-phase flow codes such as MFIX (www.mfix.org). Therefore, the benefits of this study can be realized quickly. The training provided by this project has prepared a PhD student to enter research and development careers in DOE laboratories or chemicals/energy-related industries.

  6. Plasma flow measurements in a simulated low earth orbit plasma

    SciTech Connect (OSTI)

    Gabriel, S.B. (California Institute of Technology, Jet Propulsion Laboratory, Electrical Power and Propulsion Section, Pasadena, CA); Mccoy, J.E. (NASA, Johnson Space Center, Houston, TX); Carruth, M.R. Jr. (NASA, Marshall Space Flight Center, Huntsville, AL)

    1982-01-01T23:59:59.000Z

    The employment of large, higher power solar arrays for space operation has been considered, taking into account a utilization of high operating voltages. In connection with the consideration of such arrays, attention must be given to the fact that the ambient environment of space contains a tenuous low energy plasma which can interact with the high voltage array causing power 'leakage' and arcing. An investigation has been conducted with the aim to simulate the behavior of such an array in low-earth-orbit (LEO). During the experiments, local concentrations of the 'leakage' current were observed when the panel was at a high voltage. These concentrations could overload or damage a small area of cells in a large string. It was hypothesized that this effect was produced by electrostatic focusing of the particles by the sheath fields. To verify this experimentally, an end-effect Langmuir probe was employed. The obtained results are discussed.

  7. Stochastic Simulations and Sensitivity Analysis of Plasma Flow

    SciTech Connect (OSTI)

    Lin, Guang; Karniadakis, George E.

    2008-08-01T23:59:59.000Z

    For complex physical systems with large number of random inputs, it will be very expensive to perform stochastic simulations for all of the random inputs. Stochastic sensitivity analysis is introduced in this paper to rank the significance of random inputs, provide information on which random input has more influence on the system outputs and the coupling or interaction effect among different random inputs. There are two types of numerical methods in stochastic sensitivity analysis: local and global methods. The local approach, which relies on a partial derivative of output with respect to parameters, is used to measure the sensitivity around a local operating point. When the system has strong nonlinearities and parameters fluctuate within a wide range from their nominal values, the local sensitivity does not provide full information to the system operators. On the other side, the global approach examines the sensitivity from the entire range of the parameter variations. The global screening methods, based on One-At-a-Time (OAT) perturbation of parameters, rank the significant parameters and identify their interaction among a large number of parameters. Several screening methods have been proposed in literature, i.e., the Morris method, Cotter's method, factorial experimentation, and iterated fractional factorial design. In this paper, the Morris method, Monte Carlo sampling method, Quasi-Monte Carlo method and collocation method based on sparse grids are studied. Additionally, two MHD examples are presented to demonstrate the capability and efficiency of the stochastic sensitivity analysis, which can be used as a pre-screening technique for reducing the dimensionality and hence the cost in stochastic simulations.

  8. MULTIDIMENSIONAL NUMERICAL SIMULATION OF THE REACTING FLOW IN A PULSE COMBUSTOR \\Lambda

    E-Print Network [OSTI]

    MULTIDIMENSIONAL NUMERICAL SIMULATION OF THE REACTING FLOW IN A PULSE COMBUSTOR \\Lambda Daniel L to study the behavior of pulse combustors. Our approach is based on the use of higher­order Godunov meth of pulse combustor is based on a Helmholtz resonator -- a burning cycle drives a resonant pressure wave

  9. Large Eddy Simulation Analysis of Flow Field Inside a High-g Combustor

    E-Print Network [OSTI]

    Raman, Venkat

    Large Eddy Simulation Analysis of Flow Field Inside a High-g Combustor C. Heye , C. Lietz , J-compact combustors (UCC) are a technology for reducing the size of combustors. In these combustors the fuel and air results exhibit significant entrainment of fuel into recirculation zones inside the combustor, however

  10. Simulation of water flow and solute transport in free-drainage lysimeters and field soils with

    E-Print Network [OSTI]

    Flury, Markus

    Simulation of water flow and solute transport in free-drainage lysimeters and field soils for studying the fate and transport of chemicals in soil. Large-scale field lysimeters are used to assess pesticide behaviour and radionuclide transport, and are assumed to represent natural field conditions better

  11. Numerical simulations of gas-particle flows with combustion Julien NUSSBAUM

    E-Print Network [OSTI]

    Paris-Sud XI, Université 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

  12. Resistive MHD Simulations of Laminar Round Jets with Application to Magnetic Nozzle Flows

    E-Print Network [OSTI]

    Araya, Daniel

    2012-02-14T23:59:59.000Z

    physics. This new code is validated against known solutions to MHD channel flows and new results are presented for simulations of a laminar round jet subject to a constant applied magnetic field as well as the diverging magnetic field of a current loop...

  13. Mathematical Modeling and Simulation for Applications of Fluid Flow in Porous Media \\Lambda

    E-Print Network [OSTI]

    Ewing, Richard E.

    Mathematical Modeling and Simulation for Applications of Fluid Flow in Porous Media \\Lambda Richard descriptions at various length scales, modeling the effects of this heterogeneity of the porous medium a computer code has been developed which gives concrete quantitative results for the total model, this out

  14. Flow Simulations of a Rotating MidSized Rim Driven Wind Turbine

    E-Print Network [OSTI]

    Maccabe, Barney

    Flow Simulations of a Rotating MidSized Rim Driven Wind Turbine Bryan E. Kaiser1 , Andrew B: poroseva@unm.edu Introduction Conventional horizontal axis wind turbines (HAWTs) require harvesting. To overcome this limitation, small to midsized wind turbine designs capable of power

  15. A Coupled Approach for Plasma-Based Flow Control Simulations of Wing Sections

    E-Print Network [OSTI]

    Roy, Subrata

    a role in momentum coupling, though as noted in Ref. 10 there is no significant heating of the airA Coupled Approach for Plasma-Based Flow Control Simulations of Wing Sections Datta V. Gaitonde Vehicles Directorate Kettering University Air Force Research Laboratory Flint, MI 48504 Wright

  16. Apparatus and method for interaction phenomena with world modules in data-flow-based simulation

    DOE Patents [OSTI]

    Xavier, Patrick G. (Albuquerque, NM); Gottlieb, Eric J. (Corrales, NM); McDonald, Michael J. (Albuquerque, NM); Oppel, III, Fred J. (Albuquerque, NM)

    2006-08-01T23:59:59.000Z

    A method and apparatus accommodate interaction phenomenon in a data-flow-based simulation of a system of elements, by establishing meta-modules to simulate system elements and by establishing world modules associated with interaction phenomena. World modules are associated with proxy modules from a group of meta-modules associated with one of the interaction phenomenon. The world modules include a communication world, a sensor world, a mobility world, and a contact world. World modules can be further associated with other world modules if necessary. Interaction phenomenon are simulated in corresponding world modules by accessing member functions in the associated group of proxy modules. Proxy modules can be dynamically allocated at a desired point in the simulation to accommodate the addition of elements in the system of elements such as a system of robots, a system of communication terminals, or a system of vehicles, being simulated.

  17. Multiscale Simulation of Blood Flow in Brain Arteries with an Aneurysm

    SciTech Connect (OSTI)

    Leopold Grinberg; Vitali Morozov; Dmitry A. Fedosov; Joseph Insley; Michael Papka; Kalyan Kumaran; George Karniadakis

    2013-04-24T23:59:59.000Z

    Multi-scale modeling of arterial blood flow can shed light on the interaction between events happening at micro- and meso-scales (i.e., adhesion of red blood cells to the arterial wall, clot formation) and at macro-scales (i.e., change in flow patterns due to the clot). Coupled numerical simulations of such multi-scale flow require state-of-the-art computers and algorithms, along with techniques for multi-scale visualizations. This animation presents results of studies used in the development of a multi-scale visualization methodology. First we use streamlines to show the path the flow is taking as it moves through the system, including the aneurysm. Next we investigate the process of thrombus (blood clot) formation, which may be responsible for the rupture of aneurysms, by concentrating on the platelet blood cells, observing as they aggregate on the wall of the aneurysm

  18. Simulation of hydrogen and hydrogen-assisted propane ignition in Pt catalyzed microchannel

    SciTech Connect (OSTI)

    Seshadri, Vikram; Kaisare, Niket S. [Department of Chemical Engineering, Indian Institute of Technology - Madras, Chennai 600 036 (India)

    2010-11-15T23:59:59.000Z

    This paper deals with self-ignition of catalytic microburners from ambient cold-start conditions. First, reaction kinetics for hydrogen combustion is validated with experimental results from the literature, followed by validation of a simplified pseudo-2D microburner model. The model is then used to study the self-ignition behavior of lean hydrogen/air mixtures in a Platinum-catalyzed microburner. Hydrogen combustion on Pt is a very fast reaction. During cold start ignition, hydrogen conversion reaches 100% within the first few seconds and the reactor dynamics are governed by the ''thermal inertia'' of the microburner wall structure. The self-ignition property of hydrogen can be used to provide the energy required for propane ignition. Two different modes of hydrogen-assisted propane ignition are considered: co-feed mode, where the microburner inlet consists of premixed hydrogen/propane/air mixtures; and sequential feed mode, where the inlet feed is switched from hydrogen/air to propane/air mixtures after the microburner reaches propane ignition temperature. We show that hydrogen-assisted ignition is equivalent to selectively preheating the inlet section of the microburner. The time to reach steady state is lower at higher equivalence ratio, lower wall thermal conductivity, and higher inlet velocity for both the ignition modes. The ignition times and propane emissions are compared. Although the sequential feed mode requires slightly higher amount of hydrogen, the propane emissions are at least an order of magnitude lower than the other ignition modes. (author)

  19. Numerical simulations of aggregate breakup in bounded and unbounded turbulent flows

    E-Print Network [OSTI]

    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.

  20. Simulation of coastal flow fields when the incident solar radiation is obscured

    SciTech Connect (OSTI)

    Molenkamp, C.R.

    1986-12-01T23:59:59.000Z

    In the aftermath of a large scale nuclear exchange, smoke from fires started by the explosions would be lofted into the troposphere and lower stratosphere. If sufficient amounts are injected, this smoke would be so thick that very little solar radiation would penetrate to the ground. The ground surface, obscured from insolation by the smoke, would cool rapidly leading to temperature decreases of 10 to 25/sup 0/C in the lower atmosphere. Among the many possible effects accompanying this cooling, a suggestion has been made that regions of enhanced and persistent precipitation could occur along continental coastlines due to the response of the flow fields to the more rapid cooling of air over land than over the oceans. This paper describes a simulation intended to investigate this super land breeze hypothesis using a mesoscale model that has been used to simulate normal land and sea breeze flows. The simulation shows that fog and clouds form over both land and sea with the net result that there is no dramatic temperature difference at the continental coastline and no significant induced flow or vertical motion. This simulation again contravenes the super land breeze precipitation hypothesis. In addition, it points out the moderating effect cloud and fog formation would have on the rate of cooling over the continents.

  1. One- and two-dimensional Stirling machine simulation using experimentally generated reversing flow turbuulence models

    SciTech Connect (OSTI)

    Goldberg, L.F. [Univ. of Minnesota, Minneapolis, MN (United States)

    1990-08-01T23:59:59.000Z

    The activities described in this report do not constitute a continuum but rather a series of linked smaller investigations in the general area of one- and two-dimensional Stirling machine simulation. The initial impetus for these investigations was the development and construction of the Mechanical Engineering Test Rig (METR) under a grant awarded by NASA to Dr. Terry Simon at the Department of Mechanical Engineering, University of Minnesota. The purpose of the METR is to provide experimental data on oscillating turbulent flows in Stirling machine working fluid flow path components (heater, cooler, regenerator, etc.) with particular emphasis on laminar/turbulent flow transitions. Hence, the initial goals for the grant awarded by NASA were, broadly, to provide computer simulation backup for the design of the METR and to analyze the results produced. This was envisaged in two phases: First, to apply an existing one-dimensional Stirling machine simulation code to the METR and second, to adapt a two-dimensional fluid mechanics code which had been developed for simulating high Rayleigh number buoyant cavity flows to the METR. The key aspect of this latter component was the development of an appropriate turbulence model suitable for generalized application to Stirling simulation. A final-step was then to apply the two-dimensional code to an existing Stirling machine for which adequate experimental data exist. The work described herein was carried out over a period of three years on a part-time basis. Forty percent of the first year`s funding was provided as a match to the NASA funds by the Underground Space Center, University of Minnesota, which also made its computing facilities available to the project at no charge.

  2. TOUGH Simulations of the Updegraff's Set of Fluid and Heat Flow Problems

    SciTech Connect (OSTI)

    Moridis, G.J.; Pruess (editor), K.

    1992-11-01T23:59:59.000Z

    The TOUGH code [Pruess, 1987] for two-phase flow of water, air, and heat in penneable media has been exercised on a suite of test problems originally selected and simulated by C. D. Updegraff [1989]. These include five 'verification' problems for which analytical or numerical solutions are available, and three 'validation' problems that model laboratory fluid and heat flow experiments. All problems could be run without any code modifications (*). Good and efficient numerical performance, as well as accurate results were obtained throughout. Additional code verification and validation problems from the literature are briefly summarized, and suggestions are given for proper applications of TOUGH and related codes.

  3. Large-eddy simulation of turbulent cavitating flow in a micro channel

    SciTech Connect (OSTI)

    Egerer, Christian P., E-mail: christian.egerer@aer.mw.tum.de; Hickel, Stefan; Schmidt, Steffen J.; Adams, Nikolaus A. [Institute of Aerodynamics and Fluid Mechanics, Technische Universität München, Boltzmannstr. 15, 85748 Garching bei München (Germany)

    2014-08-15T23:59:59.000Z

    Large-eddy simulations (LES) of cavitating flow of a Diesel-fuel-like fluid in a generic throttle geometry are presented. Two-phase regions are modeled by a parameter-free thermodynamic equilibrium mixture model, and compressibility of the liquid and the liquid-vapor mixture is taken into account. The Adaptive Local Deconvolution Method (ALDM), adapted for cavitating flows, is employed for discretizing the convective terms of the Navier-Stokes equations for the homogeneous mixture. ALDM is a finite-volume-based implicit LES approach that merges physically motivated turbulence modeling and numerical discretization. Validation of the numerical method is performed for a cavitating turbulent mixing layer. Comparisons with experimental data of the throttle flow at two different operating conditions are presented. The LES with the employed cavitation modeling predicts relevant flow and cavitation features accurately within the uncertainty range of the experiment. The turbulence structure of the flow is further analyzed with an emphasis on the interaction between cavitation and coherent motion, and on the statistically averaged-flow evolution.

  4. Coarse-grained simulations of vortex dynamics and transition in complex high-Re flows

    SciTech Connect (OSTI)

    Grinstein, Fernando F [Los Alamos National Laboratory

    2011-01-21T23:59:59.000Z

    Turbulent flow complexity in applications in engineering, geophysics and astrophysics typically requires achieving accurate and dependable large scale predictions of highly nonlinear processes with under-resolved computer simulation models. Laboratory observations typically demonstrate the end outcome of complex non-linear three-dimensional physical processes with many unexplained details and mechanisms. Carefully controlled computational experiments based on the numerical solution of the conservation equations for mass, momentum, and energy, provide insights into the underlying flow dynamics. Relevant computational fluid dynamics issues to be addressed relate to the modeling of the unresolved tlow conditions at the subgrid scale (SGS) level - within a computational cell, and at the supergrid (SPG) scale - at initialization and beyond computational boundaries. SGS and SPG information must be prescribed for closure of the equations solved numerically. SGS models appear explicitly or implicitly as additional source tenns in the modified flow equations solved by the numerical solutions being calculated, while SPG models provide the necessary set of initial and boundary conditions that must be prescribed to ensure unique well-posed solutions. From this perspective, it is clear that the simulation process is inherently determined by the SGS and SPG information prescription process. On the other hand, observables in laboratory experiments are always characterized by the finite scales of the instrumental resolution of measuring/visualizing devices, and subject as well to SPG issues. It is thus important to recognize the inherently intrusive nature of observations based on numerical or laboratory experiments. Ultimately, verification and validation (V & V) frameworks and appropriate metrics for the specific problems at hand are needed to establish predictability of the simulation model. Direct numerical simulation (DNS) - resolving all relevant space/time scales, is prohibitively expensive in the foreseeable future for most practical flows of interest at moderate-to-high Reynolds number (Re). On the other end of the simulation spectrum are the Reynolds-Averaged Navier-Stokes (RANS) approaches - which model the turbulent effects. In the coarsegrained large eddy simulation (LES) strategies, the large energy containing structures are resolved, the smaller structures are filtered out, and unresolved SGS effects are modeled. By necessity - rather than choice, LES effectively becomes the intermediate approach between DNS and RANS. Extensive work has demonstrated that predictive simulations of turbulent velocity fields are possible using a particular LES denoted implicit LES (ILES), using the class of nonoscillatory finite-volume (NFV) numerical algorithms. Use of the modified equation as framework for theoretical analysis, demonstrates that leading truncation tenns associated with NFV methods provide implicit SGS models of mixed anisotropic type and regularized motion of discrete observables. Tests in fundamental applications ranging from canonical to very complex flows indicate that ILES is competitive with conventional LES in the LES realm proper - flows driven by large scale features. High-Re flows are vortex dominated and governed by short convective timescales compared to those of diffusion, and kinematically characterized at the smallest scales by slender worm vortices with insignificant internal structure. This motivates nominally inviscid ILES methods capable of capturing the high-Re dissipation dynamics and of handling vortices as shocks in shock capturing schemes. Depending on flow regimes, initial conditions, and resolution, additional modeling may be needed to emulate SGS driven physics, such as backscatter, chemical reaction, material mixing, and near-wall flow-dynamics - where typically-intertwined SGS/SPG issues need to be addressed. A major research focus is recognizing when additional explicit models and/or numerical treatments are needed and ensuring that mixed explicit and implicit SGS models can effectively act in

  5. Simulated effects of climate change on the Death Valley regional ground-water flow system, Nevada and California

    SciTech Connect (OSTI)

    D`Agnese, F.A.; O`Brien, G.M.; Faunt, C.C.; San Juan, C.A.

    1999-04-01T23:59:59.000Z

    The US Geological Survey, in cooperation with the US Department of Energy, is evaluating the geologic and hydrologic characteristics of the Death Valley regional flow system as part of the Yucca Mountain Project. As part of the hydrologic investigation, regional, three-dimensional conceptual and numerical ground-water-flow models have been developed to assess the potential effects of past and future climates on the regional flow system. A simulation that is based on climatic conditions 21,000 years ago was evaluated by comparing the simulated results to observation of paleodischarge sites. Following acceptable simulation of a past climate, a possible future ground-water-flow system, with climatic conditions that represent a doubling of atmospheric carbon dioxide, was simulated. The steady-state simulations were based on the present-day, steady-state, regional ground-water-flow model. The finite-difference model consisted of 163 rows, 153 columns, and 3 layers and was simulated using MODFLOWP. Climate changes were implemented in the regional ground-water-flow model by changing the distribution of ground-water recharge. Global-scale, average-annual, simulated precipitation for both past- and future-climate conditions developed elsewhere were resampled to the model-grid resolution. A polynomial function that represents the Maxey-Eakin method for estimating recharge from precipitation was used to develop recharge distributions for simulation.

  6. An implicit centered finite-difference simulation for free surface flows in a rocking tank

    E-Print Network [OSTI]

    Jobst, William Edward

    1982-01-01T23:59:59.000Z

    include the liquid movement in closed containers such as tank trucks on highways and railroads, liquid fuel tanks in space vehicles' and contained liquid cargo in oceangoing vessels. Interest in this particular fluid phenomenon has grown consider...AN IMPLICIT CENTERED FINITE-DIFFERENCE SIMULATION FOR FREE SURFACE FLOWS IN A ROCKING TANK A Thesis by WILLIAM EDWARD JOBST Submitted to the Graduate College of Texas A8M University in partial fulfillment of the requirement for the degree...

  7. Simulating the dissociation of CO/sub 2/ in a supersonic nonequilibrium plasma flow

    SciTech Connect (OSTI)

    Grigor'eva, T.M.; Fridman, A.A.; Levitskii, A.A.; Polak, L.S.; Potapkin, B.V.; Rusanov, V.D.

    1986-11-01T23:59:59.000Z

    Gas-dynamic and chemical-kinetic equations have been used in simulating CO/sub 2/ dissociation in a supersonic flow of nonequilibrium plasma. The energy performance and the degree of conversion of CO/sub 2/ have been related to the specific energy deposition in the vibrational degrees of freedom. It is shown that the degree of conversion may attain about 30% in a constant-pressure reactor with comparatively small expansion angles.

  8. All-optical cavity-based simulator of noise-assisted transport

    E-Print Network [OSTI]

    Silvia Viciani; Manuela Lima; Marco Bellini; Filippo Caruso

    2015-04-19T23:59:59.000Z

    Recent theoretical and experimental efforts have shown the remarkable and counter-intuitive role of noise in enhancing the transport efficiency of complex systems. Here, we realize simple, scalable, and controllable optical fiber cavity networks that allow us to simulate the performance of transport networks for different conditions of interference, dephasing and disorder. In particular, we experimentally demonstrate that the transport efficiency reaches a maximum when varying the external dephasing noise, i.e. a bell-like shape behavior that had been predicted only theoretically. These optical platforms are very promising simulators of transport phenomena, and could be used, in particular, to design and test optimal topologies of artificial light-harvesting structures for future solar energy technologies.

  9. All-optical cavity-based simulator of noise-assisted transport

    E-Print Network [OSTI]

    Viciani, Silvia; Bellini, Marco; Caruso, Filippo

    2015-01-01T23:59:59.000Z

    Recent theoretical and experimental efforts have shown the remarkable and counter-intuitive role of noise in enhancing the transport efficiency of complex systems. Here, we realize simple, scalable, and controllable optical fiber cavity networks that allow us to simulate the performance of transport networks for different conditions of interference, dephasing and disorder. In particular, we experimentally demonstrate that the transport efficiency reaches a maximum when varying the external dephasing noise, i.e. a bell-like shape behavior that had been predicted only theoretically. These optical platforms are very promising simulators of transport phenomena, and could be used, in particular, to design and test optimal topologies of artificial light-harvesting structures for future solar energy technologies.

  10. Theory and simulations of the scaling of magnetic reconnection with symmetric shear flow

    SciTech Connect (OSTI)

    Cassak, P. A. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States)

    2011-07-15T23:59:59.000Z

    The scaling of magnetic reconnection in the presence of an oppositely directed sub-Alfvenic shear flow parallel to the reconnecting magnetic field is studied using analytical scaling arguments and two-dimensional two-fluid numerical simulations of collisionless (Hall) reconnection. Previous studies noted that the reconnection rate falls and the current sheet tilts with increasing flow speed, but no quantitative theory was presented. This study presents a physical model of the effect of shear flow on reconnection, resulting in expressions for the scaling of properties such as the reconnection rate, outflow speed, and thickness and length of the dissipation region, which are verified numerically. Differences between Hall and Sweet-Parker reconnection are pointed out. The tilting of the current sheet is explained physically and a quantitative prediction is presented and verified.

  11. Rheological properties of soft-glassy flows from hydro-kinetic simulations

    E-Print Network [OSTI]

    R. Benzi; M. Bernaschi; M. Sbragaglia; S. Succi

    2014-02-28T23:59:59.000Z

    Based on numerical simulations of a lattice kinetic model for soft-glassy materials, we characterize the global rheology of a dense emulsion-like system, under three representative load conditions: Couette flow, time-oscillating Strain and Kolmogorov flow. It is found that in all cases the rheology is described by a Herschel-Bulkley (HB) relation, $\\sigma = {\\sigma}_{Y} + A S^{\\beta}$, with the yield stress ${\\sigma}_{Y}$ largely independent of the loading scenario. A proper rescaling of the HB parameters permits to describe heterogeneous flows with space-dependent stresses, based on the notion of cooperativity, as recently proposed to characterize the degree of non-locality of stress relaxation phenomena in soft-glassy materials.

  12. Continuum modeling and simulation of granular flows through their many phases

    E-Print Network [OSTI]

    Sachith Dunatunga; Ken Kamrin

    2014-11-20T23:59:59.000Z

    We propose and numerically implement a constitutive framework for granular media that allows the material to traverse through its many common phases during the flow process. When dense, the material is treated as a pressure sensitive elasto-viscoplastic solid obeying a yield criterion and a plastic flow rule given by the $\\mu(I)$ inertial rheology of granular materials. When the free volume exceeds a critical level, the material is deemed to separate and is treated as disconnected, stress-free media. A Material Point Method (MPM) procedure is written for the simulation of this model and many demonstrations are provided in different geometries. By using the MPM framework, extremely large strains and nonlinear deformations, which are common in granular flows, are representable. The method is verified numerically and its physical predictions are validated against known results.

  13. Simulation-assisted evaluation of potential energy savings: Application to an administrative building in France 

    E-Print Network [OSTI]

    Randaxhe, F.; Bertagnolio, S.; Lemort, V.

    2012-01-01T23:59:59.000Z

    CONSUMPTION 17 MWh kWh/m? Total per year 3172 166 25 Oct 2012 RETROFIT OPTIONS SIMULATION (1) ? Implementation of energy efficient schedule, fresh air rate and new setpoint for air handling units and fan coils into the BMS: ? New indoor setpoint (occ... that only 28% of the annual energy consumption comes from the working period. These observations lead to various energy savings scenarios. Table 3: 2009 Electricty consumption period disaggregation according to SIMAUDIT model % MWh Primary Energy [MWh...

  14. Pair interaction lattice gas simulations: Flow past obstacles in two and three dimensions

    SciTech Connect (OSTI)

    Vogeler, A.; Wolf-Gladrow, D.A. (Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven (Germany))

    1993-04-01T23:59:59.000Z

    Apart from the FCHC (face-centered hypercube), Nasilowski's pair interaction lattice gas (PI) is the only known lattice gas automaton for three-dimensional hydrodynamic simulations. Unfortunately, the viscosity of PI is not isotropic. In order to determine the degree anisotropy, the authors derive fluid dynamic equations for the regime of compressible viscid flow. From relaxation measurements of waves propagating in various directions they compute the physically relevant dissipation coefficients and compare their results with theoretical predictions. Although PI shows a high degree of anisotropy, they define the mean value of the dissipation tensor as effective shear viscosity. Using this value of v[sub eff][sup 2D] = 0.35, two-dimensional simulations of flow past a cylinder yield drag coefficients in quantitative agreement with wind tunnel measurements over a range of Reynolds numbers of 5-50. Three-dimensional simulations of flow past a sphere yield qualitative agreement with various references. A fit of the results to a semi-empirical curve provides an effective value of v[sub eff][sup 2D] = 0.21 for a range of Reynolds numbers from 0.19 to 40. In order to check for finite-size effects, the authors measured the mean free path [lambda] and computed the Knudsen numbers. They obtained [lambda] [approx]1 lattice unit, corresponding to Kn = 0.01 (2D) and Kn = 0.1 (3D). They found no significant finite-size effects. 44 refs., 10 figs.

  15. Characterization and fluid flow simulation of naturally fractured Frontier sandstone, Green River Basin, Wyoming

    SciTech Connect (OSTI)

    Harstad, H. [New Mexico Tech, Socorro, NM (United States); Teufel, L.W.; Lorenz, J.C.; Brown, S.R. [Sandia National Labs., Albuquerque, NM (United States). Geomechanics Dept.

    1996-08-01T23:59:59.000Z

    Significant gas reserves are present in low-permeability sandstones of the Frontier Formation in the greater Green River Basin, Wyoming. Successful exploitation of these reservoirs requires an understanding of the characteristics and fluid-flow response of the regional natural fracture system that controls reservoir productivity. Fracture characteristics were obtained from outcrop studies of Frontier sandstones at locations in the basin. The fracture data were combined with matrix permeability data to compute an anisotropic horizontal permeability tensor (magnitude and direction) corresponding to an equivalent reservoir system in the subsurface using a computational model developed by Oda (1985). This analysis shows that the maximum and minimum horizontal permeability and flow capacity are controlled by fracture intensity and decrease with increasing bed thickness. However, storage capacity is controlled by matrix porosity and increases linearly with increasing bed thickness. The relationship between bed thickness and the calculated fluid-flow properties was used in a reservoir simulation study of vertical, hydraulically-fractured and horizontal wells and horizontal wells of different lengths in analogous naturally fractured gas reservoirs. The simulation results show that flow capacity dominates early time production, while storage capacity dominates pressure support over time for vertical wells. For horizontal wells drilled perpendicular to the maximum permeability direction a high target production rate can be maintained over a longer time and have higher cumulative production than vertical wells. Longer horizontal wells are required for the same cumulative production with decreasing bed thickness.

  16. Simulation of flood flow in a river system using artificial neural networks Hydrology and Earth System Sciences, 9(4), 313321 (2005) EGU

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    2005-01-01T23:59:59.000Z

    Simulation of flood flow in a river system using artificial neural networks 313 Hydrology and Earth System Sciences, 9(4), 313321 (2005) © EGU Simulation of flood flow in a river system using artificial Artificial neural networks (ANNs) provide a quick and flexible means of developing flood flow simulation

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

    SciTech Connect (OSTI)

    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.

  18. Comparison between RHD simulation of supercritical accretion flows and steady model with outflows

    E-Print Network [OSTI]

    Jiao, Cheng-Liang; Takeuchi, Shun; Ohsuga, Ken

    2015-01-01T23:59:59.000Z

    We apply our two-dimensional (2D), radially self-similar steady-state accretion flow model to the analysis of hydrodynamic simulation results of supercritical accretion flows. Self-similarity is checked and the input parameters for the model calculation, such as advective factor and heat capacity ratio, are obtained from time-averaged simulation data. Solutions of the model are then calculated and compared with the simulation results. We find that in the converged region of the simulation, excluding the part too close to the black hole, the radial distribution of azimuthal velocity $v_\\phi$, density $\\rho$ and pressure $p$ basically follows the self-similar assumptions, i.e. they are roughly proportional to $r^{-0.5}$, $r^{-n}$, and $r^{-(n+1)}$, respectively, where $n\\sim0.85$ for the mass injection rate of $1000L_\\mathrm{E}/c^2$, and $n\\sim0.74$ for $3000L_\\mathrm{E}/c^2$. The distribution of $v_r$ and $v_\\theta$ agrees less with self-similarity, possibly due to convective motions in the $r\\theta$ plane. Th...

  19. Simulation of Coupled Processes of Flow, Transport, and Storage of CO2 in Saline Aquifers

    SciTech Connect (OSTI)

    Wu, Yu-Shu; Chen, Zizhong; Kazemi, Hossein; Yin, Xiaolong; Pruess, Karsten; Oldenburg, Curt; Winterfeld, Philip; Zhang, Ronglei

    2014-09-30T23:59:59.000Z

    This report is the final scientific one for the award DE- FE0000988 entitled “Simulation of Coupled Processes of Flow, Transport, and Storage of CO2 in Saline Aquifers.” The work has been divided into six tasks. In task, “Development of a Three-Phase Non-Isothermal CO2 Flow Module,” we developed a fluid property module for brine-CO2 mixtures designed to handle all possible phase combinations of aqueous phase, sub-critical liquid and gaseous CO2, supercritical CO2, and solid salt. The thermodynamic and thermophysical properties of brine-CO2 mixtures (density, viscosity, and specific enthalpy of fluid phases; partitioning of mass components among the different phases) use the same correlations as an earlier fluid property module that does not distinguish between gaseous and liquid CO2-rich phases. We verified the fluid property module using two leakage scenarios, one that involves CO2 migration up a blind fault and subsequent accumulation in a secondary “parasitic” reservoir at shallower depth, and another investigating leakage of CO2 from a deep storage reservoir along a vertical fault zone. In task, “Development of a Rock Mechanical Module,” we developed a massively parallel reservoir simulator for modeling THM processes in porous media brine aquifers. We derived, from the fundamental equations describing deformation of porous elastic media, a momentum conservation equation relating mean stress, pressure, and temperature, and incorporated it alongside the mass and energy conservation equations from the TOUGH2 formulation, the starting point for the simulator. In addition, rock properties, namely permeability and porosity, are functions of effective stress and other variables that are obtained from the literature. We verified the simulator formulation and numerical implementation using analytical solutions and example problems from the literature. For the former, we matched a one-dimensional consolidation problem and a two-dimensional simulation of the Mandel-Cryer effect. For the latter, we obtained a good match of temperature and gas saturation profiles, and surface uplift, after injection of hot fluid into a model of a caldera structure. In task, “Incorporation of Geochemical Reactions of Selected Important Species,” we developed a novel mathematical model of THMC processes in porous and fractured saline aquifers, simulating geo-chemical reactions associated with CO2 sequestration in saline aquifers. Two computational frameworks, sequentially coupled and fully coupled, were used to simulate the reactions and transport. We verified capabilities of the THMC model to treat complex THMC processes during CO2 sequestration by analytical solutions and we constructed reactive transport models to analyze the THMC process quantitatively. Three of these are 1D reactive transport under chemical equilibrium, a batch reaction model with equilibrium chemical reactions, and a THMC model with CO2 dissolution. In task “Study of Instability in CO2 Dissolution-Diffusion-Convection Processes,” We reviewed literature related to the study of density driven convective flows and on the instability of CO2 dissolution-diffusion-convection processes. We ran simulations that model the density-driven flow instability that would occur during CO2 sequestration. CO2 diffused through the top of the system and dissolved in the aqueous phase there, increasing its density. Density fingers formed along the top boundary, and coalesced into a few prominent ones, causing convective flow that forced the fluid to the system bottom. These simulations were in two and three dimensions. We ran additional simulations of convective mixing with density contrast caused by variable dissolved CO2 concentration in saline water, modeled after laboratory experiments in which supercritical CO2 was circulated in the headspace above a brine saturated packed sand in a pressure vessel. As CO2 dissolved into the upper part of the saturated sand, liquid phase density increases causing instability and setting off convective mixing. We obtained good agreement

  20. Three-dimensional Simulation of Magnetized Cloud Fragmentation Induced by Nonlinear Flows and Ambipolar Diffusion

    E-Print Network [OSTI]

    Takahiro Kudoh; Shantanu Basu

    2008-04-27T23:59:59.000Z

    We demonstrate that the formation of collapsing cores in subcritical clouds is accelerated by nonlinear flows, by performing three-dimensional non-ideal MHD simulations. An initial random supersonic (and trans-Alfvenic) turbulent-like flow is input into a self-gravitating gas layer that is threaded by a uniform magnetic field (perpendicular to the layer) such that the initial mass-to-flux ratio is subcritical. Magnetic ambipolar diffusion occurs very rapidly initially due to the sharp gradients introduced by the turbulent flow. It subsequently occurs more slowly in the traditional near-quasistatic manner, but in regions of greater mean density than present in the initial state. The overall timescale for runaway growth of the first core(s) is several times, 10^6 yr, even though previous studies have found a timescale of several times, 10^7 yr when starting with linear perturbations and similar physical parameters. Large-scale supersonic flows exist in the cloud and provide an observationally testable distinguishing characteristic from core formation due to linear initial perturbations. However, the nonlinear flows have decayed sufficiently that the relative infall motions onto the first core are subsonic, as in the case of starting from linear initial perturbations. The ion infall motions are very similar to those of neutrals; however, they lag the neutral infall in directions perpendicular to the mean magnetic field direction and lead the neutral infall in the direction parallel to the mean magnetic field.

  1. Status of the TOUGH-FLAC simulator and recent applications related to coupled fluid flow and crustal deformations

    E-Print Network [OSTI]

    Rutqvist, J.

    2011-01-01T23:59:59.000Z

    Analytical Methods in Geomechanics 17, 577–598. Liu, H.H. ,J.E. , 2003. Coupled geomechanics and reservoir simulation.coupling porous flow and geomechanics. Society of Petroleum

  2. Development and verification of a numerical simulator to calculate the bottom hole flowing pressures in multiphase systems 

    E-Print Network [OSTI]

    Rasool, Syed Ahmed

    1994-01-01T23:59:59.000Z

    A vast amount of research has been conducted on the subject of pressure drop in muldphase flow systems. The simulator developed for this research incorporates the Beggs and Brill model for pressure drop prediction with an equation of state...

  3. A simulation code to assist designing space missions of the Airwatch type

    E-Print Network [OSTI]

    T. Montaruli; R. Bellotti; F. Cafagna; M. Circella; C. N. De Marzo; P. Lipari

    1998-10-06T23:59:59.000Z

    The design of an Airwatch type space mission can greatly benefit from a flexible simulation code for establishing the values of the main parameters of the experiment. We present here a code written for this purpose. The cosmic ray primary spectrum at very high energies, the atmosphere modelling, the fluorescence yield, the photon propagation and the detector response are taken into account in order to optimize the fundamental design parameters of the experiment, namely orbit height, field of view, mirror radius, number of pixels of the focal plane, threshold of photo-detection. The optimization criterion will be to maximize counting rates versus mission cost, which imposes limits both on weight and power consumption. Preliminary results on signals with changing energy and zenith angle of incident particles are shown.

  4. Numerical simulation of coastal flows when solar radiation is blocked by smoke

    SciTech Connect (OSTI)

    Molenkamp, C. R.

    1989-05-01T23:59:59.000Z

    Smoke from fires ignited in a large-scale nuclear exchange would greatly reduce the flux of solar radiation at the ground and lead to rapid cooling over continental regions. Because of its large heat capacity, the ocean would cool more slowly so that a thermal gradient would tend to develop at the continental coastlines. In order to investigate the hypothesis that these thermal gradients would lead to zones of persistent precipitation along the coastlines, a modified version of the Colorado State University Mesoscale Model has been used to simulate the evolution of atmospheric flows for both West and East coasts assuming a moderate westerly synoptic flow of 5 m s/sup /minus/1/. In both cases a layer of fog forms over the ground, effectively limiting the rate of cooling over land. This fog layer grows in height as the atmosphere aloft cools, forming a stratus cloud. Moisture from the ocean surface, mixed vertically into a radiatively cooled atmosphere, causes a cloud layer to form over the ocean as well. With both land and sea covered by clouds, there is no differential cooling, anomalous flow fields, or enhanced precipitation. These simulations also demonstrate the important role of moisture in moderating the initial rate of atmospheric cooling when solar radiation is blocked by smoke.

  5. Relative performance of body fitted and fictitious domain simulations of flow through fixed packed beds of spheres

    E-Print Network [OSTI]

    Apte, Sourabh V.

    porescale flow in complex configurations of fixed packed beds of spheres at moderate pore Reynolds numbersRelative performance of body fitted and fictitious domain simulations of flow through fixed packed beds of spheres Justin Finn , Sourabh V. Apte School of Mechanical Industrial and Manufacturing

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

    E-Print Network [OSTI]

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

    2013-01-01T23:59:59.000Z

    The grid-to-rod fretting (GTRF) problem in pressurized water reactors is a flow-induced vibration problem that results in wear and failure of the fuel rods in nuclear assemblies. In order to understand the fluid dynamics of GTRF and to build an archival database of turbulence statistics for various configurations, implicit large-eddy simulations of time-dependent single-phase turbulent flow have been performed in 3x3 and 5x5 rod bundles with a single grid spacer. To assess the computational mesh and resolution requirements, a method for quantitative assessment of unstructured meshes with no-slip walls is described. The calculations have been carried out using Hydra-TH, a thermal-hydraulics code developed at Los Alamos for the Consortium for Advanced Simulation of Light water reactors, a United States Department of Energy Innovation Hub. Hydra-TH uses a second-order implicit incremental projection method to solve the single-phase incompressible Navier-Stokes equations. The simulations explicitly resolve the la...

  7. Numerical simulation of groundwater flow and contaminant transport at the K, L, and P areas of the Savannah River Site, Aiken, South Carolina

    SciTech Connect (OSTI)

    Not Available

    1989-11-01T23:59:59.000Z

    The Department of Energy (DOE) is preparing an Environmental Impact Statement (EIS) as part of the process for continuing operation of three reactors at the Savannah River Site (SRS). As required by the National Environmental Policy Act (NEPA), the EIS must address the potential environmental consequences to human health and the environment of this major federal action.'' Some of the possible consequences are related to subsurface transport of radionuclides released to seepage basins during normal reactor operation. To assist in the evaluation of the potential subsurface environmental impacts of these releases, Camp Dresser McKee Inc. (CDM) was contracted in June of 1989 to develop a three-dimensional groundwater flow and contaminant transport model which will simulate the movement of radionuclides at each of the reactor areas after they enter the groundwater system through the seepage basins. This report describes the development, calibration, and simulation results of the groundwater flow and contaminant transport model developed for this task. 10 refs., 63 figs., 11 tabs.

  8. DENSE MULTIPHASE FLOW SIMULATION: CONTINUUM MODEL FOR POLY-DISPERSED SYSTEMS USING KINETIC THEORY

    SciTech Connect (OSTI)

    Moses Bogere

    2011-08-31T23:59:59.000Z

    The overall objective of the project was to verify the applicability of the FCMOM approach to the kinetic equations describing the particle flow dynamics. For monodispersed systems the fundamental equation governing the particle flow dynamics is the Boltzmann equation. During the project, the FCMOM was successfully applied to several homogeneous and in-homogeneous problems in different flow regimes, demonstrating that the FCMOM has the potential to be used to solve efficiently the Boltzmann equation. However, some relevant issues still need to be resolved, i.e. the homogeneous cooling problem (inelastic particles cases) and the transition between different regimes. In this report, the results obtained in homogeneous conditions are discussed first. Then a discussion of the validation results for in-homogeneous conditions is provided. And finally, a discussion will be provided about the transition between different regimes. Alongside the work on development of FCMOM approach studies were undertaken in order to provide insights into anisotropy or particles kinetics in riser hydrodynamics. This report includes results of studies of multiphase flow with unequal granular temperatures and analysis of momentum re-distribution in risers due to particle-particle and fluid-particle interactions. The study of multiphase flow with unequal granular temperatures entailed both simulation and experimental studies of two particles sizes in a riser and, a brief discussion of what was accomplished will be provided. And finally, a discussion of the analysis done on momentum re-distribution of gas-particles flow in risers will be provided. In particular a discussion of the remaining work needed in order to improve accuracy and predictability of riser hydrodynamics based on two-fluid models and how they can be used to model segregation in risers.

  9. Simulations for Complex Fluid Flow Problems from Berkeley Lab's Center for Computational Sciences and Engineering (CCSE)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    The Center for Computational Sciences and Engineering (CCSE) develops and applies advanced computational methodologies to solve large-scale scientific and engineering problems arising in the Department of Energy (DOE) mission areas involving energy, environmental, and industrial technology. The primary focus is in the application of structured-grid finite difference methods on adaptive grid hierarchies for compressible, incompressible, and low Mach number flows. The diverse range of scientific applications that drive the research typically involve a large range of spatial and temporal scales (e.g. turbulent reacting flows) and require the use of extremely large computing hardware, such as the 153,000-core computer, Hopper, at NERSC. The CCSE approach to these problems centers on the development and application of advanced algorithms that exploit known separations in scale; for many of the application areas this results in algorithms are several orders of magnitude more efficient than traditional simulation approaches.

  10. TOUGH2: A general-purpose numerical simulator for multiphase nonisothermal flows

    SciTech Connect (OSTI)

    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.

  11. Fast and Informative Flow Simulations in a Building by Using Fast Fluid Dynamics Model on Graphics Processing Unit

    E-Print Network [OSTI]

    Chen, Qingyan "Yan"

    Fast and Informative Flow Simulations in a Building by Using Fast Fluid Dynamics Model on Graphics solve Navier-Stokes equations and other transportation equations for energy and species at a speed of 50 it in parallel on a Graphics Processing Unit (GPU). This study validated the FFD on the GPU by simulating

  12. Prediction of effects of hydraulic fracturing using reservoir and well flow simulation

    SciTech Connect (OSTI)

    Mineyuki Hanano; Tayuki Kondo

    1992-01-01T23:59:59.000Z

    This paper presents a method to predict and evaluate effects of hydraulic fracturing jobs by using reservoir and well flow numerical simulation. The concept of the method i5 that steam production rate at the operating well head pressure is predicted with different fracture conditions which would be attained by the hydraulic fracturing jobs. Then, the effects of the hydraulic fracturing is evaluated by comparing the predicted steam production rate and that before the hydraulic fracturing. This course of analysis will suggest how large fracture should be created by the fracturing job to attain large enough increase in steam production at the operating condition and the best scheme of the hydraulic fracturing job.

  13. Turbulent flow over a house in a simulated hurricane boundary layer

    E-Print Network [OSTI]

    Taylor, Zachary; Gurka, Roi; Kopp, Gregory

    2009-01-01T23:59:59.000Z

    Every year hurricanes and other extreme wind storms cause billions of dollars in damage worldwide. For residential construction, such failures are usually associated with roofs, which see the largest aerodynamic loading. However, determining aerodynamic loads on different portions of North American houses is complicated by the lack of clear load paths and non-linear load sharing in wood frame roofs. This problem of fluid-structure interaction requires both wind tunnel testing and full-scale structural testing. A series of wind tunnel tests have been performed on a house in a simulated atmospheric boundary layer (ABL), with the resulting wind-induced pressures applied to the full-scale structure. The ABL was simulated for flow over open country terrain where both velocity and turbulence intensity profiles, as well as spectra, were matched with available full scale measurements for this type of terrain. The first set of measurements was 600 simultaneous surface pressure measurements over the entire house. A key...

  14. Simulation of Branching Blood Flows on Parallel Computers1 Xue Yue, Feng-Nan Hwang, Robin Shandas, Xiao-Chuan Cai

    E-Print Network [OSTI]

    Cai, Xiao-Chuan

    Simulation of Branching Blood Flows on Parallel Computers1 Xue Yue, Feng-Nan Hwang, Robin Shandas nonlinearly implicit algorithm for the numerical simulation of some branching blood flow problems, which-Stokes equations that we use to model the blood flow in the left anterior descending coronary artery. Key words

  15. Modeling and Simulation of Two-Phase Two-Component Flow with Disappearing Nonwetting Phase

    E-Print Network [OSTI]

    Neumann, Rebecca; Ippisch, Olaf

    2012-01-01T23:59:59.000Z

    Carbon Capture and Storage (CCS) is a recently discussed new technology, aimed at allowing an ongoing use of fossil fuels while preventing the produced CO2 to be released to the atmosphere. CSS can be modeled with two components (water and CO2) in two phases (liquid and CO2). To simulate the process, a multiphase flow equation with equilibrium phase exchange is used. One of the big problems arising in two-phase two-component flow simulations is the disappearance of the nonwetting phase, which leads to a degeneration of the equations satisfied by the saturation. A standard choice of primary variables, which is the pressure of one phase and the saturation of the other phase, cannot be applied here. We developed a new approach using the pressure of the nonwetting phase and the capillary pressure as primary variables. One important advantage of this approach is the fact that we have only one set of primary variables that can be used for the biphasic as well as the monophasic case. We implemented this new choice o...

  16. CFD Simulation of 3D Flow field in a Gas Centrifuge

    SciTech Connect (OSTI)

    Dongjun Jiang; Shi Zeng [Tsinghua University, Beijing, 100084 (China)

    2006-07-01T23:59:59.000Z

    A CFD method was used to study the whole flow field in a gas centrifuge. In this paper, the VSM (Vector Splitting Method) of the FVM (Finite Volume Method) was used to solve the 3D Navier-Stokes equations. An implicit second-order upwind scheme was adopted. The numerical simulation was successfully performed on a parallel cluster computer and a convergence result was obtained. The simulation shows that: in the withdrawal chamber, a strong detached shock wave is formed in front of the scoop; as the radial position increases, the shock becomes stronger and the distance to scoop front surface is smaller. An oblique shock forms in the clearance between the scoop and the centrifuge wall; behind the shock-wave, the radially-inward motion of gas is induced because of the imbalance of the pressure gradient and the centrifugal force. In the separation chamber, a countercurrent is introduced. This indicates that CFD method can be used to study the complex three-dimensional flow field of gas centrifuges. (authors)

  17. Energy Simulation of Integrated Multiple-Zone Variable Refrigerant Flow System

    SciTech Connect (OSTI)

    Shen, Bo [ORNL] [ORNL; Rice, C Keith [ORNL] [ORNL; Baxter, Van D [ORNL] [ORNL

    2013-01-01T23:59:59.000Z

    We developed a detailed steady-state system model, to simulate the performance of an integrated five-zone variable refrigerant flow (VRF)heat pump system. The system is multi-functional, capable of space cooling, space heating, combined space cooling and water heating, and dedicated water heating. Methods were developed to map the VRF performance in each mode, based on the abundant data produced by the equipment system model. The performance maps were used in TRNSYS annual energy simulations. Using TRNSYS, we have successfully setup and run cases for a multiple-split, VRF heat pump and dehumidifier combination in 5-zone houses in 5 climates that control indoor dry-bulb temperature and relative humidity. We compared the calculated energy consumptions for the VRF heat pump against that of a baseline central air source heat pump, coupled with electric water heating and the standalone dehumidifiers. In addition, we investigated multiple control scenarios for the VRF heat pump, i.e. on/off control, variable indoor air flow rate, and using different zone temperature setting schedules, etc. The energy savings for the multiple scenarios were assessed.

  18. Some Specific CASL Requirements for Advanced Multiphase Flow Simulation of Light Water Reactors

    SciTech Connect (OSTI)

    R. A. Berry

    2010-11-01T23:59:59.000Z

    Because of the diversity of physical phenomena occuring in boiling, flashing, and bubble collapse, and of the length and time scales of LWR systems, it is imperative that the models have the following features: • Both vapor and liquid phases (and noncondensible phases, if present) must be treated as compressible. • Models must be mathematically and numerically well-posed. • The models methodology must be multi-scale. A fundamental derivation of the multiphase governing equation system, that should be used as a basis for advanced multiphase modeling in LWR coolant systems, is given in the Appendix using the ensemble averaging method. The remainder of this work focuses specifically on the compressible, well-posed, and multi-scale requirements of advanced simulation methods for these LWR coolant systems, because without these are the most fundamental aspects, without which widespread advancement cannot be claimed. Because of the expense of developing multiple special-purpose codes and the inherent inability to couple information from the multiple, separate length- and time-scales, efforts within CASL should be focused toward development of a multi-scale approaches to solve those multiphase flow problems relevant to LWR design and safety analysis. Efforts should be aimed at developing well-designed unified physical/mathematical and high-resolution numerical models for compressible, all-speed multiphase flows spanning: (1) Well-posed general mixture level (true multiphase) models for fast transient situations and safety analysis, (2) DNS (Direct Numerical Simulation)-like models to resolve interface level phenmena like flashing and boiling flows, and critical heat flux determination (necessarily including conjugate heat transfer), and (3) Multi-scale methods to resolve both (1) and (2) automatically, depending upon specified mesh resolution, and to couple different flow models (single-phase, multiphase with several velocities and pressures, multiphase with single velocity and pressure, etc.) A unified, multi-scale approach is advocated to extend the necessary foundations and build the capability to simultaneously solve the fluid dynamic interface problems (interface resolution) as well as multiphase mixtures (homogenization).

  19. A Many-Task Parallel Approach for Multiscale Simulations of Subsurface Flow and Reactive Transport

    SciTech Connect (OSTI)

    Scheibe, Timothy D.; Yang, Xiaofan; Schuchardt, Karen L.; Agarwal, Khushbu; Chase, Jared M.; Palmer, Bruce J.; Tartakovsky, Alexandre M.

    2014-12-16T23:59:59.000Z

    Continuum-scale models have long been used to study subsurface flow, transport, and reactions but lack the ability to resolve processes that are governed by pore-scale mixing. Recently, pore-scale models, which explicitly resolve individual pores and soil grains, have been developed to more accurately model pore-scale phenomena, particularly reaction processes that are controlled by local mixing. However, pore-scale models are prohibitively expensive for modeling application-scale domains. This motivates the use of a hybrid multiscale approach in which continuum- and pore-scale codes are coupled either hierarchically or concurrently within an overall simulation domain (time and space). This approach is naturally suited to an adaptive, loosely-coupled many-task methodology with three potential levels of concurrency. Each individual code (pore- and continuum-scale) can be implemented in parallel; multiple semi-independent instances of the pore-scale code are required at each time step providing a second level of concurrency; and Monte Carlo simulations of the overall system to represent uncertainty in material property distributions provide a third level of concurrency. We have developed a hybrid multiscale model of a mixing-controlled reaction in a porous medium wherein the reaction occurs only over a limited portion of the domain. Loose, minimally-invasive coupling of pre-existing parallel continuum- and pore-scale codes has been accomplished by an adaptive script-based workflow implemented in the Swift workflow system. We describe here the methods used to create the model system, adaptively control multiple coupled instances of pore- and continuum-scale simulations, and maximize the scalability of the overall system. We present results of numerical experiments conducted on NERSC supercomputing systems; our results demonstrate that loose many-task coupling provides a scalable solution for multiscale subsurface simulations with minimal overhead.

  20. Simulation of conjugate driven cavity flow using a Chebyshev-Multidomain method

    SciTech Connect (OSTI)

    Huckaby, E.D.; Catton, I.

    1999-07-01T23:59:59.000Z

    The driven cavity problem with a temperature gradient is solved as a conjugate problem and compared with the nonconjugate case. Solid-fluid interface conditions are developed for the Chebyshev-Multidomain method which is used to simulate the coupled system. Steady-state solutions are examined at M = 0.3 for a square-cavity at Re = 350 and Re = 3,200 and for a cylindrical cavity at Re = 350. The results show that there are at least slight conjugate effects under most conditions but these effects are generally confined to the solution of the temperature distribution. Transient solutions at Re = 10{sup 4} show effects on the velocity field due to the chaotic nature of the flow.

  1. TOUGH2: A general-purpose numerical simulator for multiphase fluid and heat flow

    SciTech Connect (OSTI)

    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.

  2. Effects of mesh density and flow conditioning in simulating 7-pin wire wrapped fuel pins.

    SciTech Connect (OSTI)

    Smith, J. G.; Babin, B. R.; Pointer, W. D.; Fischer, P. F. (Mathematics and Computer Science); ( NE); (Kansas State Univ.)

    2008-01-01T23:59:59.000Z

    In response to the goals outlined by the U.S. Department of Energy's Global Nuclear Energy Partnership program, Argonne National Laboratory has initiated an effort to create an integrated multi-physics multi-resolution thermal hydraulic simulation tool package for the evaluation of nuclear power plant design and safety. As part of this effort, the applicability of a variety of thermal hydraulic analysis methods for the prediction of heat transfer and fluid dynamics in the wire-wrapped fuel-rod bundles found in a fast reactor core is being evaluated. The work described herein provides an initial assessment of the capabilities of the general purpose commercial computational fluid dynamics code Star-CD for the prediction of fluid dynamic characteristics in a wire wrapped fast reactor fuel assembly. A 7-pin wire wrapped fuel rod assembly based on the dimensions of fuel elements in the concept Advanced Burner Test Reactor [1] was simulated for different mesh densities and domain configurations. A model considering a single axial span of the wire wrapped fuel assembly was initially used to assess mesh resolution effects. The influence of the inflow/outflow boundary conditions on the predicted flow fields in the single-span model were then investigated through comparisons with the central span region of models which included 3 and 5 spans. The change in grid refinement had minimal impact on the inter-channel exchange within the assembly resulting in roughly a 5 percent maximum difference. The central span of the 3-span and 5-span cases exhibits much higher velocities than the single span case,, with the largest deviation (15 to 20 percent) occurring furthest away from the wire spacer grids in the higher velocity regions. However, the differences between predicted flow fields in the 3-span and 5-span models are minimal.

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

    SciTech Connect (OSTI)

    Sanjiva Lele

    2012-10-01T23:59:59.000Z

    The target of this SciDAC Science Application was to develop a new capability based on high-order and high-resolution schemes to simulate shock-turbulence interactions and multi-material mixing in planar and spherical geometries, and to study Rayleigh-Taylor and Richtmyer-Meshkov turbulent mixing. These fundamental problems have direct application in high-speed engineering flows, such as inertial confinement fusion (ICF) capsule implosions and scramjet combustion, and also in the natural occurrence of supernovae explosions. Another component of this project was the development of subgrid-scale (SGS) models for large-eddy simulations of flows involving shock-turbulence interaction and multi-material mixing, that were to be validated with the DNS databases generated during the program. The numerical codes developed are designed for massively-parallel computer architectures, ensuring good scaling performance. Their algorithms were validated by means of a sequence of benchmark problems. The original multi-stage plan for this five-year project included the following milestones: 1) refinement of numerical algorithms for application to the shock-turbulence interaction problem and multi-material mixing (years 1-2); 2) direct numerical simulations (DNS) of canonical shock-turbulence interaction (years 2-3), targeted at improving our understanding of the physics behind the combined two phenomena and also at guiding the development of SGS models; 3) large-eddy simulations (LES) of shock-turbulence interaction (years 3-5), improving SGS models based on the DNS obtained in the previous phase; 4) DNS of planar/spherical RM multi-material mixing (years 3-5), also with the two-fold objective of gaining insight into the relevant physics of this instability and aiding in devising new modeling strategies for multi-material mixing; 5) LES of planar/spherical RM mixing (years 4-5), integrating the improved SGS and multi-material models developed in stages 3 and 5. This final report is outlined as follows. Section 2 shows an assessment of numerical algorithms that are best suited for the numerical simulation of compressible flows involving turbulence and shock phenomena. Sections 3 and 4 deal with the canonical shock-turbulence interaction problem, from the DNS and LES perspectives, respectively. Section 5 considers the shock-turbulence inter-action in spherical geometry, in particular, the interaction of a converging shock with isotropic turbulence as well as the problem of the blast wave. Section 6 describes the study of shock-accelerated mixing through planar and spherical Richtmyer-Meshkov mixing as well as the shock-curtain interaction problem In section 7 we acknowledge the different interactions between Stanford and other institutions participating in this SciDAC project, as well as several external collaborations made possible through it. Section 8 presents a list of publications and presentations that have been generated during the course of this SciDAC project. Finally, section 9 concludes this report with the list of personnel at Stanford University funded by this SciDAC project.

  4. Three-Dimensional Simulation of Forebay and Turbine Intakes Flows for the Bonneville Project

    SciTech Connect (OSTI)

    Rakowski, Cynthia L.; Richmond, Marshall C.; Serkowski, John A.; Ebner, Laurie L.

    2002-12-31T23:59:59.000Z

    Natural resource applications of computational fluid dynamics (CFD) models are becoming more frequent with the advances in computational power and the availability of commercial meshing software and verified CFD solver applications. The Bonneville Lock and Dam Project, constructed and operated by the U. S. Army Corps of Engineers, is the westernmost dam on the Columbia River, and is located about 40 miles upstream of Portland, Oregon. A set of 3D CFD models have been developed for the Bonneville Project forebay and turbine intakes; the CFD models provide a tool to predict the impact of proposed changes in operational rules both for the overall river flow patterns and near the turbine intakes. These models also offer rapid insight into the performance of proposed or existing hydraulic structures. The creation of a computational domain for Bonneville was complex and required the use of many software tools to integrate the diverse data sources that described the river and powerhouse geometry into a single computational domain. Once the computational mesh was created, flows were simulated by solving the Reynolds-averaged Navier-Stokes (RANS) equations together with a two-equation (k-epsilon) turbulence model. The model was validated using velocity data measured in reduced scale physical models and in the field.

  5. Thickness-based adaptive mesh refinement methods for multi-phase flow simulations with thin regions

    SciTech Connect (OSTI)

    Chen, Xiaodong [The State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China); Yang, Vigor, E-mail: vigor.yang@aerospace.gatech.edu [School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0150 (United States)

    2014-07-15T23:59:59.000Z

    In numerical simulations of multi-scale, multi-phase flows, grid refinement is required to resolve regions with small scales. A notable example is liquid-jet atomization and subsequent droplet dynamics. It is essential to characterize the detailed flow physics with variable length scales with high fidelity, in order to elucidate the underlying mechanisms. In this paper, two thickness-based mesh refinement schemes are developed based on distance- and topology-oriented criteria for thin regions with confining wall/plane of symmetry and in any situation, respectively. Both techniques are implemented in a general framework with a volume-of-fluid formulation and an adaptive-mesh-refinement capability. The distance-oriented technique compares against a critical value, the ratio of an interfacial cell size to the distance between the mass center of the cell and a reference plane. The topology-oriented technique is developed from digital topology theories to handle more general conditions. The requirement for interfacial mesh refinement can be detected swiftly, without the need of thickness information, equation solving, variable averaging or mesh repairing. The mesh refinement level increases smoothly on demand in thin regions. The schemes have been verified and validated against several benchmark cases to demonstrate their effectiveness and robustness. These include the dynamics of colliding droplets, droplet motions in a microchannel, and atomization of liquid impinging jets. Overall, the thickness-based refinement technique provides highly adaptive meshes for problems with thin regions in an efficient and fully automatic manner.

  6. General Relativistic Magnetohydrodynamic Simulations of Magnetically Choked Accretion Flows around Black Holes

    SciTech Connect (OSTI)

    McKinney, Jonathan C.; Tchekhovskoy, Alexander; Blandford, Roger D.; ,

    2012-04-26T23:59:59.000Z

    Black hole (BH) accretion flows and jets are qualitatively affected by the presence of ordered magnetic fields. We study fully three-dimensional global general relativistic magnetohydrodynamic (MHD) simulations of radially extended and thick (height H to cylindrical radius R ratio of |H/R| {approx} 0.2-1) accretion flows around BHs with various dimensionless spins (a/M, with BH mass M) and with initially toroidally-dominated ({phi}-directed) and poloidally-dominated (R-z directed) magnetic fields. Firstly, for toroidal field models and BHs with high enough |a/M|, coherent large-scale (i.e. >> H) dipolar poloidal magnetic flux patches emerge, thread the BH, and generate transient relativistic jets. Secondly, for poloidal field models, poloidal magnetic flux readily accretes through the disk from large radii and builds-up to a natural saturation point near the BH. While models with |H/R| {approx} 1 and |a/M| {le} 0.5 do not launch jets due to quenching by mass infall, for sufficiently high |a/M| or low |H/R| the polar magnetic field compresses the inflow into a geometrically thin highly non-axisymmetric 'magnetically choked accretion flow' (MCAF) within which the standard linear magneto-rotational instability is suppressed. The condition of a highly-magnetized state over most of the horizon is optimal for the Blandford-Znajek mechanism that generates persistent relativistic jets with and 100% efficiency for |a/M| {approx}> 0.9. A magnetic Rayleigh-Taylor and Kelvin-Helmholtz unstable magnetospheric interface forms between the compressed inflow and bulging jet magnetosphere, which drives a new jet-disk oscillation (JDO) type of quasi-periodic oscillation (QPO) mechanism. The high-frequency QPO has spherical harmonic |m| = 1 mode period of {tau} {approx} 70GM/c{sup 3} for a/M {approx} 0.9 with coherence quality factors Q {approx}> 10. Overall, our models are qualitatively distinct from most prior MHD simulations (typically, |H/R| << 1 and poloidal flux is limited by initial conditions), so they should prove useful for testing accretion-jet theories and measuring a/M in systems such as SgrA* and M87.

  7. An isogeometric variational multiscale method for large-eddy simulation of coupled multi-ion transport in turbulent flow

    SciTech Connect (OSTI)

    Bauer, Georg; Gamnitzer, Peter [Institute for Computational Mechanics, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany)] [Institute for Computational Mechanics, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany); Gravemeier, Volker, E-mail: vgravem@lnm.mw.tum.de [Institute for Computational Mechanics, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany) [Institute for Computational Mechanics, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany); Emmy Noether Research Group “Computational Multiscale Methods for Turbulent Combustion”, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany); Wall, Wolfgang A. [Institute for Computational Mechanics, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany)] [Institute for Computational Mechanics, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany)

    2013-10-15T23:59:59.000Z

    Highlights: •We present a computational method for coupled multi-ion transport in turbulent flow. •The underlying formulation is a variational multiscale finite element method. •It is combined with the isogeometric concept for electrochemical systems. •Coupled multi-ion transport in fully turbulent Taylor–Couette flow is simulated. •This example is an important model problem for rotating cylinder electrodes. -- Abstract: Electrochemical processes, such as electroplating of large items in galvanic baths, are often coupled to turbulent flow. In this study, we propose an isogeometric residual-based variational multiscale finite element method for multi-ion transport in dilute electrolyte solutions under turbulent flow conditions. In other words, this means that the concepts of isogeometric discretization and variational multiscale methods are successfully combined for developing a method capable of simulating the challenging problem of coupled multi-ion transport in turbulent flow. We present a comprehensive three-dimensional computational method taking into account, among others, coupled convection–diffusion-migration equations subject to an electroneutrality constraint in combination with phenomenological electrode-kinetics modeling. The electrochemical subproblem is one-way coupled to turbulent incompressible flow via convection. Ionic mass transfer in turbulent Taylor–Couette flow is investigated, representing an important model problem for rotating-cylinder-electrode configurations. Multi-ion transport as considered here is an example for mass transport at high Schmidt number (Sc=1389). An isogeometric discretization is especially advantageous for the present problem, since (i) curved boundaries can be represented exactly, and (ii) it has been proven to provide very accurate solutions for flow quantities when being applied in combination with residual-based variational multiscale modeling. We demonstrate that the method is robust and provides results which are in good agreement with direct numerical simulation results as well as empirical mass-transfer correlations reported in literature.

  8. Step-flow anisotropy of the m-plane GaN (1100) grown under nitrogen-rich conditions by plasma-assisted molecular beam epitaxy

    SciTech Connect (OSTI)

    Sawicka, Marta; Siekacz, Marcin; Skierbiszewski, Czeslaw [Institute of High Pressure Physics, Polish Academy of Sciences, Sokolowska 29/37, PL-01-142 Warszawa (Poland); TopGaN Ltd., Sokolowska 29/37, PL-01-142 Warszawa (Poland); Turski, Henryk; Krysko, Marcin; DziePcielewski, Igor; Grzegory, Izabella [Institute of High Pressure Physics, Polish Academy of Sciences, Sokolowska 29/37, PL-01-142 Warszawa (Poland); Smalc-Koziorowska, Julita [Institute of High Pressure Physics, Polish Academy of Sciences, Sokolowska 29/37, PL-01-142 Warszawa (Poland); TopGaN Ltd., Sokolowska 29/37, PL-01-142 Warszawa (Poland); Warsaw University of Technology, Faculty of Material Science and Engineering, Woloska 141, PL-02-507 Warszawa (Poland)

    2011-06-15T23:59:59.000Z

    The homoepitaxial growth of m-plane (1100) GaN was investigated by plasma-assisted molecular beam epitaxy under nitrogen-rich conditions. The surface morphologies as a function of sample miscut were studied, providing evidence for a strong growth anisotropy that is a consequence of the anisotropy of Ga adatom diffusion barriers on the m-plane surface recently calculated ab initio[Lymperakis and Neugebauer, Phys. Rev. B 79, 241308(R) (2009)]. We found that substrate miscut toward [0001] implies a step flow toward <1126> while substrate miscut toward [0001] causes formation of atomic steps either perpendicular or parallel to the [0001] direction, under N-rich conditions at 730 deg C. We describe the growth conditions for achieving atomically flat m-plane GaN layers with parallel atomic steps.

  9. Reduced-Order Models of Zero-Net Mass-Flux Jets for Large-Scale Flow Control Simulations

    E-Print Network [OSTI]

    Mittal, Rajat

    Reduced-Order Models of Zero-Net Mass-Flux Jets for Large-Scale Flow Control Simulations Reni Raju computational tools are well suited for modeling the dynamics of zero-net mass-flux actuators, the computational vorticity, (s-1 ) I. Introduction ERO-net mass-flux (ZNMF) actuators or "synthetic jets" have potential

  10. Lattice Boltzmann method and gas-kinetic BGK scheme in the low-Mach number viscous flow simulations

    E-Print Network [OSTI]

    Xu, Kun

    and collisions process. On the other hand, the gas-kinetic BGK scheme is a finite volume scheme, where the timeLattice Boltzmann method and gas-kinetic BGK scheme in the low-Mach number viscous flow simulations method (LBM) and the gas-kinetic BGK scheme are based on the numerical discretization of the Boltzmann

  11. Massive first-principles simulation provides insight into flame anchoring in a hydrogen-rich jet in cross-flow.

    E-Print Network [OSTI]

    in cross-flow. When gas turbine designers want to use gasified biomass for stationary power generation is far more reactive than the methane that is the traditional gas turbine fuel. This reactivity leads Science Simulations Provide New Insights to Aid Hydrogen Gas Turbine Development NREL Highlights SCIENCE

  12. Numerical simulation of the flow field and the lifting forces in the bristle tip region of a brush seal

    E-Print Network [OSTI]

    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...

  13. Development and Validation of a Parallel MHD Code for the Simulation of Self-Field MPDT Flows

    E-Print Network [OSTI]

    Choueiri, Edgar

    . The conservation relations for the internal energy density of electrons, % ! , can be written as, Y % ! Y Q `ac), % , which includes the internal energy, kinetic energy and the energy in the magnetic field. The dissipativeDevelopment and Validation of a Parallel MHD Code for the Simulation of Self-Field MPDT Flows K

  14. A Convective-like Energy-Stable Open Boundary Condition for Simulations of Incompressible Flows

    E-Print Network [OSTI]

    Dong, Suchuan

    2015-01-01T23:59:59.000Z

    We present a new energy-stable open boundary condition, and an associated numerical algorithm, for simulating incompressible flows with outflow/open boundaries. This open boundary condition ensures the energy stability of the system, even when strong vortices or backflows occur at the outflow boundary. Under certain situations it can be reduced to a form that can be analogized to the usual convective boundary condition. One prominent feature of this boundary condition is that it provides a control over the velocity on the outflow/open boundary. This is not available with the other energy-stable open boundary conditions from previous works. Our numerical algorithm treats the proposed open boundary condition based on a rotational velocity-correction type strategy. It gives rise to a Robin-type condition for the discrete pressure and a Robin-type condition for the discrete velocity on the outflow/open boundary, respectively at the pressure and the velocity sub-steps. We present extensive numerical experiments on...

  15. Accelerating moderately stiff chemical kinetics in reactive-flow simulations using GPUs

    E-Print Network [OSTI]

    Niemeyer, Kyle E

    2014-01-01T23:59:59.000Z

    The chemical kinetics ODEs arising from operator-split reactive-flow simulations were solved on GPUs using explicit integration algorithms. Nonstiff chemical kinetics of a hydrogen oxidation mechanism (9 species and 38 irreversible reactions) were computed using the explicit fifth-order Runge-Kutta-Cash-Karp method, and the GPU-accelerated version performed faster than single- and six-core CPU versions by factors of 126 and 25, respectively, for 524,288 ODEs. Moderately stiff kinetics, represented with mechanisms for hydrogen/carbon-monoxide (13 species and 54 irreversible reactions) and methane (53 species and 634 irreversible reactions) oxidation, were computed using the stabilized explicit second-order Runge-Kutta-Chebyshev (RKC) algorithm. The GPU-based RKC implementation demonstrated an increase in performance of nearly 59 and 10 times, for problem sizes consisting of 262,144 ODEs and larger, than the single- and six-core CPU-based RKC algorithms using the hydrogen/carbon-monoxide mechanism. With the met...

  16. Fully Nonlinear Edge Gyrokinetic Simulations of Kinetic Geodesic-Acoustic Modes and Boundary Flows

    SciTech Connect (OSTI)

    Xu, X Q; Belli, E; Bodi, K; Candy, J; Chang, C S; Cohen, B I; Cohen, R H; Colella, P; Dimits, A M; Dorr, M R; Gao, Z; Hittinger, J A; Ko, S; Krasheninnikov, S; McKee, G R; Nevins, W M; Rognlien, T D; Snyder, P B; Suh, J; Umansky, M V

    2008-09-18T23:59:59.000Z

    We present edge gyrokinetic neoclassical simulations of tokamak plasmas using the fully nonlinear (full-f) continuum code TEMPEST. A nonlinear Boltzmann model is used for the electrons. The electric field is obtained by solving the 2D gyrokinetic Poisson Equation. We demonstrate the following: (1) High harmonic resonances (n > 2) significantly enhance geodesic-acoustic mode (GAM) damping at high-q (tokamak safety factor), and are necessary to explain both the damping observed in our TEMPEST q-scans and experimental measurements of the scaling of the GAM amplitude with edge q{sub 95} in the absence of obvious evidence that there is a strong q dependence of the turbulent drive and damping of the GAM. (2) The kinetic GAM exists in the edge for steep density and temperature gradients in the form of outgoing waves, its radial scale is set by the ion temperature profile, and ion temperature inhomogeneity is necessary for GAM radial propagation. (3) The development of the neoclassical electric field evolves through different phases of relaxation, including GAMs, their radial propagation, and their long-time collisional decay. (4) Natural consequences of orbits in the pedestal and scrape-off layer region in divertor geometry are substantial non-Maxwellian ion distributions and flow characteristics qualitatively like those observed in experiments.

  17. COARSE-GRID SIMULATION OF REACTING AND NON-REACTING GAS-PARTICLE FLOWS

    SciTech Connect (OSTI)

    Sankaran Sundaresan

    2004-03-01T23:59:59.000Z

    The principal goal of this project, funded under the ''DOE Vision 21 Virtual Demonstration Initiative'' is virtual demonstration of circulating fluidized bed performance. We had proposed a ''virtual demonstration tool'', which is based on the open-domain CFD code MFIX. The principal challenge funded through this grant is to devise and implement in this CFD code sound physical models for the rheological characteristics of the gas-particle mixtures. Within the past year, which was the third year of the project, we have made the following specific advances. (a) We have completed a study of the impact of sub-grid models of different levels of detail on the results obtained in coarse-grid simulations of gas-particle flow. (b) We have also completed a study of a model problem to understand the effect of wall friction, which was proved in our earlier work to be very important for stable operation of standpipes in a circulating fluidized bed circuit. These are described in a greater detail in this report.

  18. Investigation of basic processes in a lithium Lorentz force accelerator through plasma flow simulation

    E-Print Network [OSTI]

    Choueiri, Edgar

    ". Presently Assistant Professor, Physics Department, Whitworth College, WA. Chief Scientist at the Electric such as robotic and piloted exploration of the moon, mars and the outer planets, had been shown[6

  19. Direct numerical simulations of multiphase flow with applications to basaltic volcanism and planetary evolution

    E-Print Network [OSTI]

    Suckale, Jenny

    2011-01-01T23:59:59.000Z

    Multiphase flows are an essential component of natural systems: They affect the explosivity of volcanic eruptions, shape the landscape of terrestrial planets, and govern subsurface flow in hydrocarbon reservoirs. Advancing ...

  20. Object-Oriented Modelling and Simulation of Air Flow in Data Centres Based on a Quasi-3D Approach for Energy Optimisation

    E-Print Network [OSTI]

    Como, Giacomo

    ­5]. On the other hand, power delivery, electricity consumption, and heat management studies for data centre) simulation is extensively used for simulate airflow and heating components in data centres. CFD modellingObject-Oriented Modelling and Simulation of Air Flow in Data Centres Based on a Quasi-3D Approach

  1. Module Development and Simulation of the Variable Refrigerant Flow Air Conditioning System under Cooling Conditions in Energyplus

    E-Print Network [OSTI]

    Zhou, Y.; Wu, J.; Wang, R.; Shiochi, S.

    2006-01-01T23:59:59.000Z

    ICEBO2006, Shenzhen, China HVAC Technologies for Energy Efficiency Vol.IV-1-2 Module Development and Simulation of the Variable Refrigerant Flow Air Conditioning System under Cooling Conditions in Energyplus Yanping Zhou Jingyi..., especially for those who ICEBO2006, Shenzhen, China HVAC Technologies for Energy Efficiency Vol.IV-1-2 show some interest about high-efficiency systems like VRF, it becomes of interest to compare the VRF to other systems and evaluate VRF?s performance...

  2. Comparative Analysis of Natural Convection Flows Simulated by both the Conservation and Incompressible Forms of the Navier-Stokes Equations in a Differentially-Heated Square Cavity

    SciTech Connect (OSTI)

    Richard C. Martineau; Ray A. Berry; Aurélia Esteve; Kurt D. Hamman; Dana A. Knoll; Ryosuke Park; William Taitano

    2009-01-01T23:59:59.000Z

    This report illustrates a comparative study to analyze the physical differences between numerical simulations obtained with both the conservation and incompressible forms of the Navier-Stokes equations for natural convection flows in simple geometries. The purpose of this study is to quantify how the incompressible flow assumption (which is based upon constant density advection, divergence-free flow, and the Boussinesq gravitational body force approximation) differs from the conservation form (which only assumes that the fluid is a continuum) when solving flows driven by gravity acting upon density variations resulting from local temperature gradients. Driving this study is the common use of the incompressible flow assumption in fluid flow simulations for nuclear power applications in natural convection flows subjected to a high heat flux (large temperature differences). A series of simulations were conducted on two-dimensional, differentially-heated rectangular geometries and modeled with both hydrodynamic formulations. From these simulations, the selected characterization parameters of maximum Nusselt number, average Nusselt number, and normalized pressure reduction were calculated. Comparisons of these parameters were made with available benchmark solutions for air with the ideal gas assumption at both low and high heat fluxes. Additionally, we generated body force, velocity, and divergence of velocity distributions to provide a basis for further analysis. The simulations and analysis were then extended to include helium at the Very High Temperature gas-cooled Reactor (VHTR) normal operating conditions. Our results show that the consequences of incorporating the incompressible flow assumption in high heat flux situations may lead to unrepresentative results. The results question the use of the incompressible flow assumption for simulating fluid flow in an operating nuclear reactor, where large temperature variations are present. The results show that the use of the incompressible flow assumption with the Boussinesq gravitational body force approximation should be restricted to flows where the density change of a fluid particle along a pathline is negligible.

  3. Sandia National Laboratories: New Mexico Small Business Assistance

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

    Small Business Assistance Sandia-Atmocean Inc.'s New Mexico Small Business Assistance Project On March 13, 2014, in Computational Modeling & Simulation, Energy, News, News &...

  4. Helioseismic Holography of Simulated Solar Convection and Prospects for the Detection of Small-Scale Subsurface Flows

    E-Print Network [OSTI]

    D. C. Braun; A. C. Birch; D. Benson; R. F. Stein; Å. Nordlund

    2007-08-01T23:59:59.000Z

    We perform helioseismic holography on realistic solar convection simulations and compare the observed travel-time perturbations with the expected travel times from the horizontal flows in the simulations computed from forward models under the assumption of the Born approximation. We demonstrate reasonable agreement between the observed and model travel times which reinforces the validity of helioseismic holography in the detection of subsurface horizontal flows. From the variation of the signal-to-noise ratio with depth, we conclude that the helioseismic detection of individual flow structures with spatial scales of supergranulation or smaller is not possible for depths below about 5 Mm below the surface over time scales less than a day. Approximately half of the observed signal originates within the first 2 Mm below the surface. A consequence of this is a rapid decrease (and reversal in some cases) of the travel-time perturbations with depth due to the contribution to the measurements of oppositely directed surface flows in neighboring convective cells. This confirms an earlier interpretation of similar effects reported from observations.

  5. Large-Eddy Simulation of the Bachalo-Johnson Flow, with Shock...

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

    proposals for carbon capture and sequestration also involve supersonic flows in the compressors. This project will focus on the upper surface of a transport aircraft wing,...

  6. A Unified Multi-Scale Model for Pore-Scale Flow Simulations in...

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

    Subsurface Flow and Transport Science Theme: Terrestrial & Subsurface Ecosystems Instruments: X-ray Computed Tomography Volume: 78 Issue: 1 Pages: 108-118 Publication year: 2014...

  7. A Flux-Limited Numerical Method for the MHD Equations to Simulate Propulsive Plasma Flows

    E-Print Network [OSTI]

    Choueiri, Edgar

    to be effective tools in plasma propulsion research, a higher order accu- rate solver that captures MHD shocks approach, numerical simulations are valuable tools in plasma thruster research. More- over, simulations can Simula- tions The importance of numerical simulation in advancing plasma thruster research was realized

  8. Simulating Electron Transport and Synchrotron Emission in Radio Galaxies: Shock Acceleration and Synchrotron Aging in Three-Dimensional Flows

    E-Print Network [OSTI]

    I. L. Tregillis; T. W. Jones; Dongsu Ryu

    2001-04-18T23:59:59.000Z

    We present the first three-dimensional MHD radio galaxy simulations that explicitly model transport of relativistic electrons, including diffusive acceleration at shocks as well as radiative and adiabatic cooling in smooth flows. We discuss three simulations of light Mach 8 jets, designed to explore the effects of shock acceleration and radiative aging on the nonthermal particle populations that give rise to synchrotron and inverse-Compton radiations. We also conduct detailed synthetic radio observations of our simulated objects. We have gained several key insights from this approach: 1. The jet head in these multidimensional simulations is extremely complex. The classical jet termination shock is often absent, but motions of the jet terminus spin a ``shock-web complex'' within the backflowing jet material of the head. 2. Understanding the spectral distribution of energetic electrons in these simulations relies partly upon understanding the shock-web complex, for it can give rise to distributions that confound interpretation in terms of the standard model for radiative aging of radio galaxies. 3. The magnetic field outside of the jet itself becomes very intermittent and filamentary in these simulations, yet adiabatic expansion causes most of the cocoon volume to be occupied by field strengths considerably diminished below the nominal jet value. Thus population aging rates vary considerably from point to point.

  9. Simulation assisted design of a gallium phosphide np photovoltaic junction Charles R. Allen, Jong-Hyeok Jeon , Jerry M. Woodall

    E-Print Network [OSTI]

    Woodall, Jerry M.

    University, 1205 W State Street, West Lafayette, IN, USA a r t i c l e i n f o Article history: Received 27 February 2010 Keywords: Gallium phosphide Solar cell Multi-junction CPV Simulation a b s t r a c with measurements of the dark and light response. The light current was measured under an illumination of air mass

  10. Numerical Simulation of the Flow of a Power Law Fluid in an Elbow Bend

    E-Print Network [OSTI]

    Kanakamedala, Karthik

    2010-07-14T23:59:59.000Z

    A numerical study of flow of power law fluid in an elbow bend has been carried out. The motivation behind this study is to analyze the velocity profiles, especially the pattern of the secondary flow of power law fluid in a bend as there are several...

  11. CFD Simulation and Experimental Testing of Multiphase Flow Inside the MVP Electrical Submersible Pump

    E-Print Network [OSTI]

    Rasmy Marsis, Emanuel 1983-

    2012-08-16T23:59:59.000Z

    The MVP is a special type of Electrical Submersible Pumps (ESPs) manufactured by Baker Hughes, model no. G470, and is capable of handling multiphase flow up to 70% Gas Volume Fraction (GVF). Flows at high GVF cause conventional ESPs to surge...

  12. A numerical method for fully resolved simulation (FRS) of rigid particleflow interactions in complex flows

    E-Print Network [OSTI]

    Apte, Sourabh V.

    and dispersion of particles due to fluctuations in the fluid flow is important to develop reduced-ordered models and engineering involve two-phase flows where solid particles of arbitrary shape and sizes are dispersed sediment transport in rivers, fluidized beds, coal-based oxy-fuel combustion chambers, biomass gasifiers

  13. Numerical Simulation of the Flow Field in 3D Eccentric Annular and 2D Centered Labyrinth Seals for Comparison with Experimental LDA Data 

    E-Print Network [OSTI]

    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 ...

  14. Numerical Simulation of Flow Field Inside a Squeeze Film Damper and the Study of the Effect of Cavitation on the Pressure Distribution

    E-Print Network [OSTI]

    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...

  15. An investigation of the effect of pore scale flow on average geochemical reaction rates using direct numerical simulation

    SciTech Connect (OSTI)

    Rafa, S. Molins; Trebotich, D.; Steefel, C. I.; Shen, C.

    2012-02-01T23:59:59.000Z

    The scale-dependence of geochemical reaction rates hinders their use in continuum scale models intended for the interpretation and prediction of chemical fate and transport in subsurface environments such as those considered for geologic sequestration of CO{sub 2}. Processes that take place at the pore scale, especially those involving mass transport limitations to reactive surfaces, may contribute to the discrepancy commonly observed between laboratory-determined and continuum-scale or field rates. Here, the dependence of mineral dissolution rates on the pore structure of the porous media is investigated by means of pore scale modeling of flow and multicomponent reactive transport. The pore scale model is comprised of high performance simulation tools and algorithms for incompressible flow and conservative transport combined with a general-purpose multicomponent geochemical reaction code. The model performs direct numerical simulation of reactive transport based on an operator-splitting approach to coupling transport and reactions. The approach is validated with a Poiseuille flow single-pore experiment and verified with an equivalent 1D continuum-scale model of a capillary tube packed with calcite spheres. Using the case of calcite dissolution as an example, the high resolution model is used to demonstrate that non-uniformity in the flow field at the pore scale has the effect of decreasing the overall reactivity of the system, even when systems with identical reactive surface area are considered. The effect becomes more pronounced as the heterogeneity of the reactive grain packing increases, particularly where the flow slows sufficiently such that the solution approaches equilibrium locally and the average rate becomes transport-limited.

  16. FullSWOF: A software for overland flow simulation / FullSWOF : un logiciel pour la simulation du ruissellement

    E-Print Network [OSTI]

    Delestre, Olivier; Darboux, Frédéric; Du, Mingxuan; James, Francois; Laguerre, Christian; Lucas, Carine; Planchon, Olivier

    2012-01-01T23:59:59.000Z

    Overland flow on agricultural fields may have some undesirable effects such as soil erosion, flood and pollutant transport. To better understand this phenomenon and limit its consequences, we developed a code using state-of-the-art numerical methods: FullSWOF (Full Shallow Water equations for Overland Flow), an object oriented code written in C++. It has been made open-source and can be downloaded from http://www.univ-orleans.fr/mapmo/soft/FullSWOF/. The model is based on the classical system of Shallow Water (SW) (or Saint-Venant system). Numerical difficulties come from the numerous dry/wet transitions and the highly-variable topography encountered inside a field. It includes runon and rainfall inputs, infiltration (modified Green-Ampt equation), friction (Darcy-Weisbach and Manning formulas). First we present the numerical method for the resolution of the Shallow Water equations integrated in FullSWOF_2D (the two-dimension version). This method is based on hydrostatic reconstruction scheme, coupled with a ...

  17. CFD Simulations of a Flow Mixing and Heat Transfer Enhancement in an Advanced LWR Nuclear Fuel Assembly

    SciTech Connect (OSTI)

    In, Wang-Kee; Chun, Tae-Hyun; Shin, Chang-Hwan; Oh, Dong-Seok [Korea Atomic Energy Research Institute, 1045 Daedeokdaero, Yuseong-Gu, Daejeon, Korea 305-353 (Korea, Republic of)

    2007-07-01T23:59:59.000Z

    A computational fluid dynamics (CFD) analysis has been performed to investigate a flow-mixing and heat-transfer enhancement caused by a mixing-vane spacer in a LWR fuel assembly which is a rod bundle. This paper presents the CFD simulations of a flow mixing and heat transfer in a fully heated 5x5 array of a rod bundle with a split-vane and hybrid-vane spacer. The CFD prediction at a low Reynolds number of 42,000 showed a reasonably good agreement of the initial heat transfer enhancement with the measured one for a partially heated experiment using a similar spacer structure. The CFD simulation also predicted the decay rate of a normalized Nusselt number downstream of the split-vane spacer which agrees fairly well with those of the experiment and the correlation. The CFD calculations for the split vane and hybrid vane at the LWR operating conditions(Re = 500,000) predicted hot fuel spots in a streaky structure downstream of the spacer, which occurs due to the secondary flow occurring in an opposite direction near the fuel rod. However, the split-vane and hybrid-vane spacers are predicted to significantly enhance the overall heat transfer of a LWR nuclear fuel assembly. (authors)

  18. Quantifying Distributed System Stability through Simulation: A Case Study of an Agent-Based System for Flow Reconstruction of DDoS Attacks

    E-Print Network [OSTI]

    Khan, Bilal

    Quantifying Distributed System Stability through Simulation: A Case Study of an Agent-Based System for Flow Reconstruction of DDoS Attacks Omer Demir Department of Computer Science City University of New denial of service (DDoS) attacks. The pro- posed system provides a description of the structure of flows

  19. FRAC-STIM: A Physics-Based Fracture Simulation, /reservoir Flow...

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

    Simulator track 4: enhanced geothermal systems (EGS) | geothermal 2015 peer review Fracture Characterization in Enhanced Geothermal Systems by Wellbore and Reservoir Analysis...

  20. Spectral element/smoothed profile method for turbulent flow simulations of waterjet propulsion systems

    E-Print Network [OSTI]

    Luo, Xian

    We have developed fast numerical algorithms [1] for flows with complex moving domains, e.g. propellers in free-space and impellers in waterjets, by combining the smoothed profile method (SPM, [2, 3, 4]) with the spectral ...

  1. ITR/ACS: Simulation Flows with Dynamic Interfaces on MultiTeraflop Computers

    E-Print Network [OSTI]

    Antaki, James F.

    , chemical, marine, materials, wind engineering sciences. These include large­amplitude vibrations such flexible aerodynamic components high aspect ratio wings blades; flows mixtures slurries; wind biofluids with elastic vessels; and materials phase transition problems. We particularly interested modeling

  2. A Novel Approach For the Simulation of Multiple Flow Mechanisms and Porosities in Shale Gas Reservoirs

    E-Print Network [OSTI]

    Yan, Bicheng

    2013-07-15T23:59:59.000Z

    The state of the art of modeling fluid flow in shale gas reservoirs is dominated by dual porosity models that divide the reservoirs into matrix blocks that significantly contribute to fluid storage and fracture networks which principally control...

  3. A front-tracking method for the simulation of three-phase flow in porous media

    E-Print Network [OSTI]

    , the simultaneous flow of oil, water, and gas in the reservoir. Practical examples include primary production below bubble point and with movable water, waterfloods in the presence of free gas, gas floods, and water

  4. Modeling, Analysis and Simulation of Multiscale Preferential Flow - 8/05-8/10 - Final Report

    SciTech Connect (OSTI)

    Ralph Showalter; Malgorzata Peszynska

    2012-07-03T23:59:59.000Z

    The research agenda of this project are: (1) Modeling of preferential transport from mesoscale to macroscale; (2) Modeling of fast flow in narrow fractures in porous media; (3) Pseudo-parabolic Models of Dynamic Capillary Pressure; (4) Adaptive computational upscaling of flow with inertia from porescale to mesoscale; (5) Adaptive modeling of nonlinear coupled systems; and (6) Adaptive modeling and a-posteriori estimators for coupled systems with heterogeneous data.

  5. PROBABILISTIC SIMULATION OF SUBSURFACE FLUID FLOW: A STUDY USING A NUMERICAL SCHEME

    SciTech Connect (OSTI)

    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.

  6. Two-Phase Flow Simulations In a Natural Rock Fracture using the VOF Method

    SciTech Connect (OSTI)

    Crandall, Dustin; Ahmadi, Goodarz; Smith, Duane H., Bromhal, Grant

    2010-01-01T23:59:59.000Z

    Standard models of two-phase flow in porous media have been shown to exhibit several shortcomings that might be partially overcome with a recently developed model based on thermodynamic principles (Hassanizadeh and Gray, 1990). This alternative two-phase flow model contains a set of new and non-standard parameters, including specific interfacial area. By incorporating interfacial area production, destruction, and propagation into functional relationships that describe the capillary pressure and saturation, a more physical model has been developed. Niessner and Hassanizadeh (2008) have examined this model numerically and have shown that the model captures saturation hysteresis with drainage/imbibition cycles. Several static experimental studies have been performed to examine the validity of this new thermodynamically based approach; these allow the determination of static parameters of the model. To date, no experimental studies have obtained information about the dynamic parameters required for the model. A new experimental porous flow cell has been constructed using stereolithography to study two-phase flow phenomena (Crandall et al. 2008). A novel image analysis tool was developed for an examination of the evolution of flow patterns during displacement experiments (Crandall et al. 2009). This analysis tool enables the direct quantification of interfacial area between fluids by matching known geometrical properties of the constructed flow cell with locations identified as interfaces from images of flowing fluids. Numerous images were obtained from two-phase experiments within the flow cell. The dynamic evolution of the fluid distribution and the fluid-fluid interface locations were determined by analyzing these images. In this paper, we give a brief introduction to the thermodynamically based two-phase flow model, review the properties of the stereolithography flow cell, and show how the image analysis procedure has been used to obtain dynamic parameters for the numerical model. These parameters include production/destruction of interfacial area as a function of saturation and capillary pressure. Our preliminary results for primary drainage in porous media show that the specific interfacial area increased linearly with increasing gas saturation until breakthrough of the displacing gas into the exit manifold occurred.

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

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

    Schilling, Oleg; Mueschke, Nicholas J.

    2010-01-01T23:59:59.000Z

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

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

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

    Schilling, Oleg [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Mueschke, Nicholas J. [Texas A and M Univ., College Station, TX (United States)

    2010-01-01T23:59:59.000Z

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

  9. Status of the TOUGH-FLAC simulator and recent applications related to coupled fluid flow and crustal deformations

    SciTech Connect (OSTI)

    Rutqvist, J.

    2010-06-01T23:59:59.000Z

    This paper presents recent advancement in and applications of TOUGH-FLAC, a simulator for multiphase fluid flow and geomechanics. The TOUGH-FLAC simulator links the TOUGH family multiphase fluid and heat transport codes with the commercial FLAC{sup 3D} geomechanical simulator. The most significant new TOUGH-FLAC development in the past few years is a revised architecture, enabling a more rigorous and tight coupling procedure with improved computational efficiency. The applications presented in this paper are related to modeling of crustal deformations caused by deep underground fluid movements and pressure changes as a result of both industrial activities (the In Salah CO{sub 2} Storage Project and the Geysers Geothermal Field) and natural events (the 1960s Matsushiro Earthquake Swarm). Finally, the paper provides some perspectives on the future of TOUGH-FLAC in light of its applicability to practical problems and the need for high-performance computing capabilities for field-scale problems, such as industrial-scale CO{sub 2} storage and enhanced geothermal systems. It is concluded that despite some limitations to fully adapting a commercial code such as FLAC{sup 3D} for some specialized research and computational needs, TOUGH-FLAC is likely to remain a pragmatic simulation approach, with an increasing number of users in both academia and industry.

  10. BREATH Version 1.1, Coupled flow and energy transport in porous media: Simulator description and user guide

    SciTech Connect (OSTI)

    Stothoff, S.A.

    1995-07-01T23:59:59.000Z

    This document describes the BREATH computer code, including the mathematical and numerical formulation for the simulator, usage description, and sample input files with corresponding output files. The BREATH computer code is designed to simulate one-dimensional flow of a liquid phase and dispersive transport of the corresponding vapor species, coupled with energy transfer, in a heterogeneous porous medium. The BREATH simulator has been developed for use in auxiliary analyses which are a part of the Nuclear Regulatory Commission Iterative Performance Assessment program. The simulator was developed in response to the observation from Total System Performance Assessments by both the Nuclear Regulatory Commission and the US Department of Energy that total-system performance at the Yucca Mountain site in Nevada is highly sensitive to the infiltration rate. Accordingly, this first version of the code is primarily intended to simulate processes important to infiltration and evaporation in climatic and hydrologic near-surface environments representative of the Yucca Mountain site. The simulation model assumes that there is an immobile solid phase, a mobile liquid phase, and an optional infinitely mobile gas phase. The liquid may have an associated vapor species, assumed to be in equilibrium with the liquid phase. The vapor phase may only move via diffusion within the gas phase. Energy may be transported in the form of enthalpy, thermal conduction, and latent heat. The temperature range is assumed to be between 0 and 100{degree}C. Available boundary conditions include six liquid-phase conditions, four vapor-species conditions, and three energy conditions, all of which may be applied independently to either end of the domain. Meteorological conditions may also be input, thereby providing additional control over boundary fluxes. Boundary conditions may be updated as often as desired.

  11. Numerical simulation of material and energy flow in an e-beam melt furnace

    SciTech Connect (OSTI)

    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.

  12. Accounting for Finite-Size Effects in Simulations of Disperse Particle-Laden Flows

    E-Print Network [OSTI]

    Mahesh, Krishnan

    flowfield: a) gravitational settling, b) fluidization by a gaseous jet, and c) fluidization by lift phase is modeled through drag and lift laws [Crowe et al. (1998)]. Several simulations of particle

  13. Multiscale simulation of blood flow in brain arteries with an aneurysm

    E-Print Network [OSTI]

    Grinberg, Leopold; Fedosov, Dmitry A; Insley, Joseph A; Papka, Michael E; Kumaran, Kalyan; Karniadakis, George Em

    2011-01-01T23:59:59.000Z

    Interfacing atomistic-based with continuum-based simulation codes is now required in many multiscale physical and biological systems. We present the first results from coupled atomistic-continuum simulations on 190,000 processors. Platelet aggregation in the patient-specific model of an aneurysm has been modeled using a high-order spectral/hp element Navier-Stokes solver with a stochastic (coarse-grained) Molecular Dynamics solver based on Dissipative Particle Dynamics (DPD).

  14. USER’S GUIDE of TOUGH2-EGS: A Coupled Geomechanical and Reactive Geochemical Simulator for Fluid and Heat Flow in Enhanced Geothermal Systems Version 1.0

    SciTech Connect (OSTI)

    Fakcharoenphol, Perapon [Colorado School of Mines; Xiong, Yi [Colorado School of Mines; Hu, Litang; Winterfeld, Philip H. [Colorado School of Mines; Xu, Tianfu [Lawrence Berkeley National Laboratory; Wu, Yu-Shu [Colorado School of Mines

    2013-05-01T23:59:59.000Z

    TOUGH2-EGS is a numerical simulation program coupling geomechanics and chemical reactions for fluid and heat flows in porous media and fractured reservoirs of enhanced geothermal systems. The simulator includes the fully-coupled geomechanical (THM) module, the fully-coupled geochemical (THC) module, and the sequentially coupled reactive geochemistry (THMC) module. The fully-coupled flow-geomechanics model is developed from the linear elastic theory for the thermo-poro-elastic system and is formulated with the mean normal stress as well as pore pressure and temperature. The chemical reaction is sequentially coupled after solution of flow equations, which provides the flow velocity and phase saturation for the solute transport calculation at each time step. In addition, reservoir rock properties, such as porosity and permeability, are subjected to change due to rock deformation and chemical reactions. The relationships between rock properties and geomechanical and chemical effects from poro-elasticity theories and empirical correlations are incorporated into the simulator. This report provides the user with detailed information on both mathematical models and instructions for using TOUGH2-EGS for THM, THC or THMC simulations. The mathematical models include the fluid and heat flow equations, geomechanical equation, reactive geochemistry equations, and discretization methods. Although TOUGH2-EGS has the capability for simulating fluid and heat flows coupled with both geomechanical and chemical effects, it is up to the users to select the specific coupling process, such as THM, THC, or THMC in a simulation. There are several example problems illustrating the applications of this program. These example problems are described in details and their input data are presented. The results demonstrate that this program can be used for field-scale geothermal reservoir simulation with fluid and heat flow, geomechanical effect, and chemical reaction in porous and fractured media.

  15. Interpretation of Flow Logs from Nevada Test Site Boreholes to Estimate Hydraulic conductivity Using Numerical Simulations Constrained by Single-Well Aquifer Tests

    SciTech Connect (OSTI)

    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.

  16. TOUGHREACT Version 2.0: A simulator for subsurface reactive transport under non-isothermal multiphase flow conditions

    SciTech Connect (OSTI)

    Xu, T.; Spycher, N.; Sonnenthal, E.; Zhang, G.; Zheng, L.; Pruess, K.

    2010-08-01T23:59:59.000Z

    TOUGHREACT is a numerical simulation program for chemically reactive non-isothermal flows of multiphase fluids in porous and fractured media, and was developed by introducing reactive chemistry into the multiphase fluid and heat flow simulator TOUGH2 V2. The first version of TOUGHREACT was released to the public through the U.S. Department of Energy's Energy Science and Technology Software Center (ESTSC) in August 2004. It is among the most frequently requested of ESTSC's codes. The code has been widely used for studies in CO{sub 2} geological sequestration, nuclear waste isolation, geothermal energy development, environmental remediation, and increasingly for petroleum applications. Over the past several years, many new capabilities have been developed, which were incorporated into Version 2 of TOUGHREACT. Major additions and improvements in Version 2 are discussed here, and two application examples are presented: (1) long-term fate of injected CO{sub 2} in a storage reservoir and (2) biogeochemical cycling of metals in mining-impacted lake sediments.

  17. Numerical simulation of flow of shear-thinning fluids in corrugated channels

    E-Print Network [OSTI]

    Aiyalur Shankaran, Rohit

    2009-05-15T23:59:59.000Z

    is subjected to a periodic increase and decrease in cross-section area. Such conditions are frequently observed in the flow of blood through blood vessels, movement of lubricating oils through the ground during the oil extraction process, in the process...

  18. Numerical simulation of flow of shear-thinning fluids in corrugated channels

    E-Print Network [OSTI]

    Aiyalur Shankaran, Rohit

    2008-10-10T23:59:59.000Z

    is subjected to a periodic increase and decrease in cross-section area. Such conditions are frequently observed in the flow of blood through blood vessels, movement of lubricating oils through the ground during the oil extraction process, in the process...

  19. COHERENT VORTEX SIMULATION (CVS) OF A FLOW PAST A NACA AIRFOIL 23012 AT RE = 1000

    E-Print Network [OSTI]

    École Normale Supérieure

    coherent vortices) and a random part (the incoherent back- ground flow) [5, 7]. The CVS method is based to compute three­dimensional turbulent mixing layers we refer to [13]. In this paper we present applications or solid obstacles, even if their shape varies in time, are modelled as a porous medium whose porosity

  20. A PARALLEL DYNAMIC-MESH LAGRANGIAN METHOD FOR SIMULATION OF FLOWS WITH DYNAMIC INTERFACES

    E-Print Network [OSTI]

    Antaki, James F.

    abound in the aerospace, automotive, biomedical, chemical, marine, materials, and wind engineering ratio wings and blades; flows of mixtures and slurries; wind-induced deformation of towers, antennas for such problems, since interfaces are naturally represented and propagated. However, the material description

  1. ITR/ACS: Simulation of Flows with Dynamic Interfaces on Multi-Teraflop Computers

    E-Print Network [OSTI]

    Antaki, James F.

    , materials, and wind engineering sciences. These include large-amplitude vibrations of such flexible aerodynamic components as high aspect ratio wings and blades; flows of mixtures and slurries; wind; interaction of biofluids with elastic vessels; and materials phase transition problems. We are particularly

  2. Multiphase flow and Encapsulation simulations using the moment of fluid method 1

    E-Print Network [OSTI]

    Sussman, Mark

    in order to demonstrate its capabilities. Examples are given in 2D, 3D axisymmetric (R-Z), and 3D (X Corporation, for the U. S. Department of Energy's National Nuclear Security Administration under contract DE. Introduction Multiphase flow plays an important role in many technical applications including ink-jet printing

  3. Theoretical and Numerical Simulation of Non-Newtonian Fluid Flow in Propped Fractures

    E-Print Network [OSTI]

    Ouyang, Liangchen

    2013-12-10T23:59:59.000Z

    the original gel. The residual gel exhibits a higher yield stress, and is difficult to remove after fracture closure. But non-Newtonian fluid has complicated rheological equation and its flow behavior in porous media is difficult to be described and modeled...

  4. Direct numerical simulation of a reacting turbulent channel flow with thermo-chemical ablation

    E-Print Network [OSTI]

    Nicoud, Franck

    species; 2) pyrolysis of the composite material resin (series of chemical reactions arising and multicompo- nent physics, multi-phase flow dynamics, thermo-structural mechanics of composite materials attack. Graphite and carbon-carbon composites are widely used because they offer excellent thermo

  5. Domain Decomposition Algorithm and Analytical Simulation of Coupled Flow in Reservoir / Well System

    E-Print Network [OSTI]

    Lazarov, Raytcho

    and on its production index. 1. Introduction The modern technology in oil and gas recovery requires new shown [2] that in a 3-D unbounded reservoir with permeability less than 1-Darcy and laminar well flow of the wall and acceleration terms in balance equation. In the present paper a model of a reservoir

  6. Numerical simulation of turbulent, oscillatory flow over sand ripples Brian C. Barr and Donald N. Slinn

    E-Print Network [OSTI]

    Slinn, Donald

    an improved understanding of oscillatory flow over sand ripples. [3] The wave bottom boundary layer (WBBL the ripple crest produce a continuously turbulent boundary layer, differing from results obtained processes; KEYWORDS: turbulent boundary layer, drag coefficient, dissipation rate Citation: Barr, B. C., D

  7. Experiences and Challenges Scaling PFLOTRAN, a PETSc-based Code for Subsurface Reactive Flow Simulations,

    E-Print Network [OSTI]

    Mills, Richard

    and dis- cretization PFLOTRAN solves a coupled system of continuum scale mass and energy conservation in the flow module of PFLOTRAN for mass and energy conservation can be summarized as [1]: t sX i + · qX i the mole fraction of species i; , H, U refer to the molar density, enthalpy, and internal energy of each

  8. Measurement and simulation of a droplet population in a turbulent flow field Rbert Bords a,1

    E-Print Network [OSTI]

    John, Volker

    online 30 May 2012 Keywords: Two-phase turbulent flow Disperse droplet population Non-intrusive are determined by non-intrusive measurements. A direct discretization of the 4D equation for the droplet size deter- mined by means of non-intrusive measurement techniques. In this way, suitable time

  9. A splitting method for numerical simulation of free surface flows of incompressible fluids with surface tension

    E-Print Network [OSTI]

    Olshanskii, Maxim A.

    with surface tension Kirill D. Nikitin Maxim A. Olshanskii Kirill M. Terekhov Yuri V. Vassilevski§ Abstract to surface tension forces. The method splits one time step into a semi-Lagrangian treatment of the surface models a free surface flow of viscous incompressible fluid subject to surface tension forces. Further

  10. Evaluating Subgrid-Scale Models for Large-Eddy Simulation of Turbulent Katabatic Flow

    E-Print Network [OSTI]

    Fedorovich, Evgeni

    of LES for reproducing stably-stratified turbulent boundary layers [2]. Under stably-stratified conditions, the characteristic length scale of the small-scale turbulent motions decrease, placing a larger analytically for a laminar slope flow in a stably- stratified environment. The Prandtl solution

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

    SciTech Connect (OSTI)

    Grinstein, Fernando F [Los Alamos National Laboratory

    2009-01-01T23:59:59.000Z

    Implicit large eddy simulation proposes to effectively rely on the use of subgrid modeling and filtering provided implicitly by physics capturing numerics. Extensive work has demonstrated that predictive simulations of turbulent velocity fields are possible using a class of high resolution, non-oscillatory finite-volume (NFV) numerical algorithms. Truncation terms associated with NFV methods implicitly provide subgrid models capable of emulating the physical dynamics of the unresolved turbulent velocity fluctuations by themselves. The extension of the approach to the substantially more difficult problem of under-resolved material mixing by an under-resolved velocity field has not yet been investigated numerically, nor are there any theories as to when the methodology may be expected to be successful. Progress in addressing these issues in studies of shock-driven scalar mixing driven by Ritchmyer-Meshkov instabilities will be reported in the context of ongoing simulations of shock-tube laboratory experiments.

  12. Gusty, gaseous flows of FIRE: galactic winds in cosmological simulations with explicit stellar feedback

    E-Print Network [OSTI]

    Muratov, Alexander L; Faucher-Giguere, Claude-Andre; Hopkins, Philip F; Quataert, Eliot; Murray, Norman

    2015-01-01T23:59:59.000Z

    We present an analysis of the galaxy-scale gaseous outflows from the FIRE (Feedback in Realistic Environments) simulations. This suite of hydrodynamic cosmological zoom simulations provides a sample of halos where star-forming giant molecular clouds are resolved to z=0, and features an explicit stellar feedback model on small scales. In this work, we focus on quantifying the gas mass ejected out of galaxies in winds and how this material travels through the halo. We correlate these quantities to star formation in galaxies throughout cosmic history. Our simulations reveal that a significant portion of every galaxy's evolution, particularly at high redshift, is dominated by bursts of star formation, which are followed by powerful gusts of galactic outflow that sweep up a large fraction of gas in the interstellar medium and send it through the circumgalactic medium. The dynamical effect of these outflows can significantly limit the amount of star formation within the affected galaxy. At low redshift, however, su...

  13. Wake Flow Simulations for a Mid-Sized Rim Driven Wind Turbine

    SciTech Connect (OSTI)

    Rob O. Hovsapian; Various

    2014-06-01T23:59:59.000Z

    The onshore land where wind farms with conventional wind turbines can be places is limited by various factors including a requirement for relatively high wind speed for turbines' efficient operations. Where such a requirement cannot be met, mid-and small-sized turbines can be a solution. In the current paper simulations for near and for wakes behind a mid-sized Rim Driven Wind Turbine developed by Keuka Energy LLC is analyzed. The purposes of this study is to better understand the wake structure for more efficient wind farm planning. Simulations are conducted with the commercial CFD software STARCCM+

  14. Numerical Simulation of Rarefied-Gas Flows about a Rotating Cylinder

    E-Print Network [OSTI]

    Riabov, Vladimir V.

    -Gas Flows, Aerodynamic Coefficients. PACS: 47.11.Mn, 47.27 ek, 47.32 Ef, 47.45 n, 47.85 Gj. NOMENCLATURE Cx. The lift and drag coefficients Cy,FM and Cx,FM , respectively, can be calculated using the formulae [6]: Cy,FM = Cy (0) + Cy (W), Cy (W) = ( /2) t W (1) Cx,FM = Cx (0) + Cx (W), Cx (W) = 0 (2) where the parameter

  15. Numerical simulation of flow distribution for pebble bed high temperature gas cooled reactors

    E-Print Network [OSTI]

    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...

  16. High-Performance Reactive Fluid Flow Simulations Using Adaptive Mesh Refinement on Thousands of Processors

    E-Print Network [OSTI]

    Rhoads, James

    Thermonuclear Flashes at the University of Chicago. FLASH is a modular, adaptive mesh, parallel simulation code to thermonuclear reactions in supernovae and novae. The FLASH code was designed to study thermonuclear flashes Thermonuclear Flashes, The University of Chicago, Chicago, IL 60637 2 Center for Applied Scientific Computing

  17. SIMULATION OF CROSS FLOW PAST A TUBE BANK EMPLOYING AN ADAPTIVE PARALLEL / VECTOR FINITE ELEMENT PROCEDURE

    E-Print Network [OSTI]

    Coutinho, Alvaro L. G. A.

    Engenharia Civil, COPPE Comissão Nacional de Energia Nuclear Universidade Federal do Rio de Janeiro 21945­970 ­ Rio de Janeiro ­ RJ ­ Brasil 21945­910 ­ Rio de Janeiro ­ RJ ­ Brasil SUMMARY The numerical simulation

  18. Visualizing Vortices in Simulated Air Flow around Bat Wings during Flight

    E-Print Network [OSTI]

    Laidlaw, David

    visualizations. #12;2. Motivation We believe that bats employ unique, extremely energy efficient aerodynamic present a case study of our efforts towards building a set of data visualization tools to aid interdisciplinary collaboration efforts towards building a set of tools for visualizing simulated airflow and its

  19. Measurement and modelling of high-resolution flow-velocity data under simulated rainfall on a

    E-Print Network [OSTI]

    solves the Saint- Venant equations in 2D, MAHLERAN uses a 1D kinematic wave in the slope direction 0022 in revised form 5 July 2007; accepted 23 July 2007 KEYWORDS Rainfall-simulation; Water erosion; Erosion algorithm that is close in principle to the diffusion-wave equation in 2D. The Darcy­ Weisbach friction

  20. Lattice-Boltzmann Simulations of Multiphase Flows in Gas-Diffusion-Layer (GDL) of a PEM Fuel Cell

    SciTech Connect (OSTI)

    Shiladitya Mukherjeea; J. Vernon Cole; Kunal Jainb; Ashok Gidwania

    2008-11-01T23:59:59.000Z

    Improved power density and freeze-thaw durability in automotive applications of Proton Exchange Membrane Fuel Cells (PEMFCs) requires effective water management at the membrane. This is controlled by a porous hydrophobic gas-diffusion-layer (GDL) inserted between the membrane catalyst layer and the gas reactant channels. The GDL distributes the incoming gaseous reactants on the catalyst surface and removes excess water by capillary action. There is, however, limited understanding of the multiphase, multi-component transport of liquid water, vapor and gaseous reactants within these porous materials. This is due primarily to the challenges of in-situ diagnostics for such thin (200 -? 300 {microns}), optically opaque (graphite) materials. Transport is typically analyzed by fitting Darcy's Law type expressions for permeability, in conjunction with capillary pressure relations based on formulations derived for media such as soils. Therefore, there is significant interest in developing predictive models for transport in GDLs and related porous media. Such models could be applied to analyze and optimize systems based on the interactions between cell design, materials, and operating conditions, and could also be applied to evaluating material design concepts. Recently, the Lattice Boltzmann Method (LBM) has emerged as an effective tool in modeling multiphase flows in general, and flows through porous media in particular. This method is based on the solution of a discrete form of the well-known Boltzmann Transport Equation (BTE) for molecular distribution, tailored to recover the continuum Navier-Stokes flow. The kinetic theory basis of the method allows simple implementation of molecular forces responsible for liquid-gas phase separation and capillary effects. The solution advances by a streaming and collision type algorithm that makes it suitable to implement for domains with complex boundaries. We have developed both single and multiphase LB models and applied them to simulate flow through porous GDL materials. We will present an overview of the methods as implemented, verification studies for both microstructure reconstruction and transport simulations, and application to single- and two-phase transport in GDL structures. The applications studies are designed to both improve understanding of transport within a given structure, and to investigate possible routes for improving material properties through microstructure design.

  1. Study of Particle Rotation Effect in Gas-Solid Flows using Direct Numerical Simulation with a Lattice Boltzmann Method

    SciTech Connect (OSTI)

    Kwon, Kyung; Fan, Liang-Shih; Zhou, Qiang; Yang, Hui

    2014-09-30T23:59:59.000Z

    A new and efficient direct numerical method with second-order convergence accuracy was developed for fully resolved simulations of incompressible viscous flows laden with rigid particles. The method combines the state-of-the-art immersed boundary method (IBM), the multi-direct forcing method, and the lattice Boltzmann method (LBM). First, the multi-direct forcing method is adopted in the improved IBM to better approximate the no-slip/no-penetration (ns/np) condition on the surface of particles. Second, a slight retraction of the Lagrangian grid from the surface towards the interior of particles with a fraction of the Eulerian grid spacing helps increase the convergence accuracy of the method. An over-relaxation technique in the procedure of multi-direct forcing method and the classical fourth order Runge-Kutta scheme in the coupled fluid-particle interaction were applied. The use of the classical fourth order Runge-Kutta scheme helps the overall IB-LBM achieve the second order accuracy and provides more accurate predictions of the translational and rotational motion of particles. The preexistent code with the first-order convergence rate is updated so that the updated new code can resolve the translational and rotational motion of particles with the second-order convergence rate. The updated code has been validated with several benchmark applications. The efficiency of IBM and thus the efficiency of IB-LBM were improved by reducing the number of the Lagragian markers on particles by using a new formula for the number of Lagrangian markers on particle surfaces. The immersed boundary-lattice Boltzmann method (IBLBM) has been shown to predict correctly the angular velocity of a particle. Prior to examining drag force exerted on a cluster of particles, the updated IB-LBM code along with the new formula for the number of Lagrangian markers has been further validated by solving several theoretical problems. Moreover, the unsteadiness of the drag force is examined when a fluid is accelerated from rest by a constant average pressure gradient toward a steady Stokes flow. The simulation results agree well with the theories for the short- and long-time behavior of the drag force. Flows through non-rotational and rotational spheres in simple cubic arrays and random arrays are simulated over the entire range of packing fractions, and both low and moderate particle Reynolds numbers to compare the simulated results with the literature results and develop a new drag force formula, a new lift force formula, and a new torque formula. Random arrays of solid particles in fluids are generated with Monte Carlo procedure and Zinchenko's method to avoid crystallization of solid particles over high solid volume fractions. A new drag force formula was developed with extensive simulated results to be closely applicable to real processes over the entire range of packing fractions and both low and moderate particle Reynolds numbers. The simulation results indicate that the drag force is barely affected by rotational Reynolds numbers. Drag force is basically unchanged as the angle of the rotating axis varies.

  2. Comparative evaluation of network flow programming and conventional reservoir system simulation models

    E-Print Network [OSTI]

    Yerramreddy, Anilkumar

    1993-01-01T23:59:59.000Z

    ANALYSIS MODELS Operating river/reservoir systems in an optimal manner is an important and com- plex area of water resources planning and management. Reservoir system operation involves: allocating storage capacity and water resources between multiple... broad array of analysis capabilities, have been developed over the past several decades to support planning studies and management decisions. Reservoir system analysis models can be categorized as (I) simulation models, (2) optimization models...

  3. MOLECULAR-KINETIC SIMULATIONS OF ESCAPE FROM THE EX-PLANET AND EXOPLANETS: CRITERION FOR TRANSONIC FLOW

    SciTech Connect (OSTI)

    Johnson, Robert E.; Volkov, Alexey N.; Erwin, Justin T. [Engineering Physics, University of Virginia, Charlottesville, VA 22904-4745 (United States)

    2013-05-01T23:59:59.000Z

    The equations of gas dynamics are extensively used to describe atmospheric loss from solar system bodies and exoplanets even though the boundary conditions at infinity are not uniquely defined. Using molecular-kinetic simulations that correctly treat the transition from the continuum to the rarefied region, we confirm that the energy-limited escape approximation is valid when adiabatic expansion is the dominant cooling process. However, this does not imply that the outflow goes sonic. Rather large escape rates and concomitant adiabatic cooling can produce atmospheres with subsonic flow that are highly extended. Since this affects the heating rate of the upper atmosphere and the interaction with external fields and plasmas, we give a criterion for estimating when the outflow goes transonic in the continuum region. This is applied to early terrestrial atmospheres, exoplanet atmospheres, and the atmosphere of the ex-planet, Pluto, all of which have large escape rates.

  4. Simulations of Blood Flow in Plain Cylindrical and Constricted Vessels with Single Cell Resolution

    E-Print Network [OSTI]

    Florian Janoschek; Federico Toschi; Jens Harting

    2011-05-31T23:59:59.000Z

    Understanding the physics of blood is challenging due to its nature as a suspension of soft particles and the fact that typical problems involve different scales. This is valid also for numerical investigations. In fact, many computational studies either neglect the existence of discrete cells or resolve relatively few cells very accurately. The authors recently developed a simple and highly efficient yet still particulate model with the aim to bridge the gap between currently applied methods. The present work focuses on its applicability to confined flows in vessels of diameters up to 100 micrometres. For hematocrit values below 30 percent, a dependence of the apparent viscosity on the vessel diameter in agreement with experimental literature data is found.

  5. Immersed Boundary Methods for High-Resolution Simulation of Atmospheric Boundary-Layer Flow Over Complex Terrain

    E-Print Network [OSTI]

    Lundquist, Katherine Ann

    2010-01-01T23:59:59.000Z

    large-eddy simulations within mesoscale simulations for windEddy Simulation of a Mesoscale Convective Internal Boundary185, 1957. Pielke, R. , Mesoscale Meteorological Modeling,

  6. Two-dimensional hydrodynamic simulation of an accretion flow with radiative cooling in a close binary system

    E-Print Network [OSTI]

    Jun'ichi Sato; Keisuke Sawada; Naofumi Ohnishi

    2003-04-14T23:59:59.000Z

    Two-dimensional numerical simulations of an accretion flow in a close binary system are performed by solving the Euler equations with radiative transfer. In the present study, the specific heat ratio is assumed to be constant while radiative cooling effect is included as a non-adiabatic process. The cooling effect of the disc is considered by discharging energy in the vertical directions from the top and bottom surfaces of the disc. We use the flux-limited diffusion approximation to calculate the radiative heat flux values. Our calculations show that a disc structure appears and the spiral shocks are formed on the disc. These features are similar to that observed in the case of an adiabatic gas with a lower specific heat ratio, $\\gamma=1.01$. It is found that when radiative cooling effect is accounted for, the mass of the disc becomes larger than that assuming $\\gamma=5/3$, and smaller than that assuming $\\gamma=1.01$. It is concluded that employing an adiabatic gas with a lower specific heat ratio is almost a valid assumption for simulating accretion disc with radiative cooling effect.

  7. Immersed Boundary Methods for High-Resolution Simulation of Atmospheric Boundary-Layer Flow Over Complex Terrain

    E-Print Network [OSTI]

    Lundquist, Katherine Ann

    2010-01-01T23:59:59.000Z

    laminar flow over a ribbed channel. v ? U n F = + U · ?U + ?dimensional channel flow with smooth and ribbed surfaces. In

  8. Numerical Simulation of the Flow Field in 3D Eccentric Annular and 2D Centered Labyrinth Seals for Comparison with Experimental LDA Data

    E-Print Network [OSTI]

    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...

  9. Development of a Darcy-Brinkman model to simulate water flow and tracer transport in a heterogeneous karstic aquifer (Val d'Orlans, France)

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Modelling karstic aquifers is problematic because the equation of references (i.e. Darcy) is adapted: i) the Darcy law used to describe the hydraulic behaviour of massive limestone, and ii) the equationDevelopment of a Darcy- Brinkman model to simulate water flow and tracer transport

  10. NUMERICAL FLOW AND TRANSPORT SIMULATIONS SUPPORTING THE SALTSTONE FACILITY PERFORMANCE ASSESSMENT

    SciTech Connect (OSTI)

    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.

  11. Time cycle analysis and simulation of material flow in MOX process layout

    SciTech Connect (OSTI)

    Chakraborty, S.; Saraswat, A.; Danny, K.M.; Somayajulu, P.S.; Kumar, A. [Nuclear Fuels Group, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085 (India)

    2013-07-01T23:59:59.000Z

    The (U,Pu)O{sub 2} MOX fuel is the driver fuel for the upcoming PFBR (Prototype Fast Breeder Reactor). The fuel has around 30% PuO{sub 2}. The presence of high percentages of reprocessed PuO{sub 2} necessitates the design of optimized fuel fabrication process line which will address both production need as well as meet regulatory norms regarding radiological safety criteria. The powder pellet route has highly unbalanced time cycle. This difficulty can be overcome by optimizing process layout in terms of equipment redundancy and scheduling of input powder batches. Different schemes are tested before implementing in the process line with the help of a software. This software simulates the material movement through the optimized process layout. The different material processing schemes have been devised and validity of the schemes are tested with the software. Schemes in which production batches are meeting at any glove box location are considered invalid. A valid scheme ensures adequate spacing between the production batches and at the same time it meets the production target. This software can be further improved by accurately calculating material movement time through glove box train. One important factor is considering material handling time with automation systems in place.

  12. Numerical Simulation of Inter-basin Groundwater Flow into Northern Yucca Flat, Nevada National Security Site, Using the Death Valley Regional Flow System Model

    SciTech Connect (OSTI)

    Pohlmann Karl,Ye Ming

    2012-03-01T23:59:59.000Z

    Models of groundwater flow for the Yucca Flat area of the Nevada National Security Site (NNSS) are under development by the U.S. Department of Energy (DOE) for corrective action investigations of the Yucca Flat-Climax Mine Corrective Action Unit (CAU). One important aspect of these models is the quantity of inter-basin groundwater flow from regional systems to the north. This component of flow, together with its uncertainty, must be properly accounted for in the CAU flow models to provide a defensible regional framework for calculations of radionuclide transport that will support determinations of the Yucca Flat-Climax Mine contaminant boundary. Because characterizing flow boundary conditions in northern Yucca Flat requires evaluation to a higher level of detail than the scale of the Yucca Flat-Climax Mine CAU model can efficiently provide, a study more focused on this aspect of the model was required.

  13. Simulations Data Simulation Type

    E-Print Network [OSTI]

    Wang, Xiaorui "Ray"

    to request different simulations data. The flow chart above demonstrates the different steps and options@ornl.gov) Autotune Drupal 7 CMS Current building energy models (BEMs), using EnergyPlus or other simulations, are unreliable because they have to constantly be calibrated to match actual energy usage data. Currently

  14. Control-volume method for numerical simulation of two-phase immiscible flow in two-and

    E-Print Network [OSTI]

    Firoozabadi, Abbas

    -dimensional discrete-fractured media J. E. P. Monteagudo and A. Firoozabadi Reservoir Engineering Research Institute-hydrocarbon formations is of high interest in hydro- carbon production. Flow in fractured-geothermal reservoirs and incompressible flow in two- and three-dimensional discrete-fractured media. The concept of cross-flow equilibrium

  15. Status of the TOUGH-FLAC simulator and recent applications related to coupled fluid flow and crustal deformations

    E-Print Network [OSTI]

    Rutqvist, J.

    2011-01-01T23:59:59.000Z

    geomechanics and reservoir simulation. Society of Petroleum Engineers (and geomechanics. Society of Petroleum Engineers Journal 11,

  16. Assisted fusion

    E-Print Network [OSTI]

    German Kälbermann

    2009-10-19T23:59:59.000Z

    A model of nuclear fusion consisting of a wave packet impinging into a well located between square one dimensional barriers is treated analytically. The wave function inside the well is calculated exactly for the assisted tunneling induced by a perturbation mimicking a constant electric field with arbitrary time dependence. Conditions are found for the enhancement of fusion.

  17. Dealing with big circulation flow, small temperature difference based on verified dynamic model simulations of a hot water district heating system

    E-Print Network [OSTI]

    Zhong, L.

    2014-01-01T23:59:59.000Z

    DEALING WITH “BIG CIRCULATION FLOW RATE, SMALL TEMPERATURE DIFFERENCE” BASED ON VERIFIED DYNAMIC MODEL SIMULATIONS OF A HOT WATER DISTRICT HEATING SYSTEM Li Lian Zhong, Senior Sales Consultant, Danfoss Automatic Controls Management (Shanghai...) Co.,Ltd, Anshan, China ABSTRACT Dynamic models of an indirect hot water district heating system were developed based on the first principle of thermodynamics. The ideal model was verified by using measured operational data. The ideal...

  18. Numerical simulation of the fluid flow and heat transfer processes during scavenging in a two-stroke engine under steady-state conditions

    SciTech Connect (OSTI)

    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.

  19. Global Evaluation of the ISBA-TRIP Continental Hydrological System. Part II: Uncertainties in River Routing Simulation Related to Flow

    E-Print Network [OSTI]

    Boyer, Edmond

    the entire globe. RRMs have been introduced into earth system models (ESMs) to convert the runoff simulated

  20. Flow Components in a NaK Test Loop Designed to Simulate Conditions in a Nuclear Surface Power Reactor

    SciTech Connect (OSTI)

    Polzin, Kurt A.; Godfroy, Thomas J. [NASA Marshall Space Flight Center Propulsion Research and Technology Applications Branch/ER24, MSFC, AL 35812 (United States)

    2008-01-21T23:59:59.000Z

    A test loop using NaK as the working fluid is presently in use to study material compatibility effects on various components that comprise a possible nuclear reactor design for use on the lunar surface. A DC electromagnetic (EM) pump has been designed and implemented as a means of actively controlling the NaK flow rate through the system and an EM flow sensor is employed to monitor the developed flow rate. These components allow for the matching of the flow rate conditions in test loops with those that would be found in a full-scale surface-power reactor. The design and operating characteristics of the EM pump and flow sensor are presented. In the EM pump, current is applied to a set of electrodes to produce a Lorentz body force in the fluid. A measurement of the induced voltage (back-EMF) in the flow sensor provides the means of monitoring flow rate. Both components are compact, employing high magnetic field strength neodymium magnets thermally coupled to a water-cooled housing. A vacuum gap limits the heat transferred from the high temperature NaK tube to the magnets and a magnetically-permeable material completes the magnetic circuit. The pump is designed to produce a pressure rise of 34.5 kPa, and the flow sensor's predicted output is roughly 20 mV at the loop's nominal flow rate of 0.114 m{sup 3}/hr.

  1. A one-way coupled, EulerLagrangian simulation of bubble coalescence in a turbulent pipe flow

    E-Print Network [OSTI]

    Mahesh, Krishnan

    modifies the speed of sound in the bubbly mixture, which has implications for marine acoustic signatures. Gas­liquid flow at microgravity conditions ­ I. Dispersed bubble and slug flow. Int. J. Multiphase- ical in many heat transfer problems where liquid water contacting a hot surface boils and the resulting

  2. A Parallel Implementation of the TOUGH2 Software Package for Large Scale Multiphase Fluid and Heat Flow Simulations

    E-Print Network [OSTI]

    Elmroth, Erik

    A Parallel Implementation of the TOUGH2 Software Package for Large Scale Multiphase Fluid and Heat groundwater flow related problems such as nuclear waste isolation, environmental remediation, and geothermal with ¢¡¤£¦¥§ ¨¡© blocks in a Yucca Mountain nuclear waste site study. Keywords. Ground water flow, grid partitioning

  3. A Parallel Implementation of the TOUGH2 Software Package for Large Scale Multiphase Fluid and Heat Flow Simulations

    E-Print Network [OSTI]

    Elmroth, Erik

    A Parallel Implementation of the TOUGH2 Software Package for Large Scale Multiphase Fluid and Heat groundwater flow related problems such as nuclear waste isolation, environmental remediation, and geothermal 6 blocks in a Yucca Mountain nuclear waste site study. Keywords. Ground water flow, grid

  4. Hydrogeologic evaluation and numerical simulation of the Death Valley regional ground-water flow system, Nevada and California

    SciTech Connect (OSTI)

    D`Agnese, F.A.; Faunt, C.C.; Turner, A.K.; Hill, M.C.

    1997-12-31T23:59:59.000Z

    Yucca Mountain is being studied as a potential site for a high-level radioactive waste repository. In cooperation with the U.S. Department of Energy, the U.S. Geological Survey is evaluating the geologic and hydrologic characteristics of the ground-water system. The study area covers approximately 100,000 square kilometers between lat 35{degrees}N., long 115{degrees}W and lat 38{degrees}N., long 118{degrees}W and encompasses the Death Valley regional ground-water flow system. Hydrology in the region is a result of both the and climatic conditions and the complex described as dominated by interbasinal flow and may be conceptualized as having two main components: a series of relatively shallow and localized flow paths that are superimposed on deeper regional flow paths. A significant component of the regional ground-water flow is through a thick Paleozoic carbonate rock sequence. Throughout the regional flow system, ground-water flow is probably controlled by extensive and prevalent structural features that result from regional faulting and fracturing. Hydrogeologic investigations over a large and hydrogeologically complex area impose severe demands on data management. This study utilized geographic information systems and geoscientific information systems to develop, store, manipulate, and analyze regional hydrogeologic data sets describing various components of the ground-water flow system.

  5. assisted laser ablation: Topics by E-print Network

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

    of producing ions from small ionization (DESI),5 desorption atmospheric pressure chemical ionization (DAPCI),6 and matrix- assisted laser Vertes, Akos 10 Numerical simulation...

  6. An approach for simulation of paraffin deposition in pipelines as a function of flow characteristics with a reference to Teesside oil pipeline

    SciTech Connect (OSTI)

    Hamouda, A.A.; Davidsen, S.

    1995-11-01T23:59:59.000Z

    Paraffin deposition is experienced in pipelines during transportation of oil when the oil temperature is cooled below its paraffin deposition temperature. The formed paraffin crystals in the bulk flow are believed to be transported by molecular, brownian diffusion and shear dispersion. Gravity settling mechanism in previous work in the authors` laboratory has been shown to contribute to the total paraffin deposition, however, to a lesser extent than the above mentioned mechanisms. The work done here demonstrates that the paraffin deposition by molecular diffusion mechanism is a dominant one. This is in agreement with other previous studies done on the paraffin deposition. In this study, however, experimental design was made to quantify this statement. The paraffin concentration gradient (dc/dr) is the driving force of the molecular diffusion mechanism (where r is the pipeline radius). In pipelines the cooling rate is one of many factors that affect the paraffin deposition profile. Equipment was designed to simulate the flow characteristics at pipeline pressure. A three dimensional model was developed for paraffin deposition rates at various flow regimes. The developed experimental approach and the designed equipment for simulating the pipeline conditions are presented in this paper.

  7. Computational fluid dynamics assessment: Volume 1, Computer simulations of the METC (Morgantown Energy Technology Center) entrained-flow gasifier: Final report

    SciTech Connect (OSTI)

    Celik, I.; Chattree, M.

    1988-07-01T23:59:59.000Z

    An assessment of the theoretical and numerical aspects of the computer code, PCGC-2, is made; and the results of the application of this code to the Morgantown Energy Technology Center (METC) advanced gasification facility entrained-flow reactor, ''the gasifier,'' are presented. PCGC-2 is a code suitable for simulating pulverized coal combustion or gasification under axisymmetric (two-dimensional) flow conditions. The governing equations for the gas and particulate phase have been reviewed. The numerical procedure and the related programming difficulties have been elucidated. A single-particle model similar to the one used in PCGC-2 has been developed, programmed, and applied to some simple situations in order to gain insight to the physics of coal particle heat-up, devolatilization, and char oxidation processes. PCGC-2 was applied to the METC entrained-flow gasifier to study numerically the flash pyrolysis of coal, and gasification of coal with steam or carbon dioxide. The results from the simulations are compared with measurements. The gas and particle residence times, particle temperature, and mass component history were also calculated and the results were analyzed. The results provide useful information for understanding the fundamentals of coal gasification and for assessment of experimental results performed using the reactor considered. 69 refs., 35 figs., 23 tabs.

  8. A Robust Four-Fluid Transient Flow Simulator as an Analysis and Decision Making Tool for Dynamic Kill Operation 

    E-Print Network [OSTI]

    Haghshenas, Arash

    2013-04-24T23:59:59.000Z

    The worst scenario of drilling operation is blowout which is uncontrolled flow of formation fluid into the wellbore. Blowouts result in environmental damage with potential risk of injuries and fatalities. Although not all ...

  9. Three-Dimensional Characteristics of Post-CHF Behaviour Within a Rod Bundle for Loss-of-Flow Simulation: Experimental and Three-Fluid Porous Media Numerical Analyses

    SciTech Connect (OSTI)

    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)

  10. Variable Density Flow Modeling for Simulation Framework for Regional Geologic CO{sub 2} Storage Along Arches Province of Midwestern United States

    SciTech Connect (OSTI)

    Joel Sminchak

    2011-09-30T23:59:59.000Z

    The Arches Province in the Midwestern U.S. has been identified as a major area for carbon dioxide (CO{sub 2}) storage applications because of the intersection of Mt. Simon sandstone reservoir thickness and permeability. To better understand large-scale CO{sub 2} storage infrastructure requirements in the Arches Province, variable density scoping level modeling was completed. Three main tasks were completed for the variable density modeling: Single-phase, variable density groundwater flow modeling; Scoping level multi-phase simulations; and Preliminary basin-scale multi-phase simulations. The variable density modeling task was successful in evaluating appropriate input data for the Arches Province numerical simulations. Data from the geocellular model developed earlier in the project were translated into preliminary numerical models. These models were calibrated to observed conditions in the Mt. Simon, suggesting a suitable geologic depiction of the system. The initial models were used to assess boundary conditions, calibrate to reservoir conditions, examine grid dimensions, evaluate upscaling items, and develop regional storage field scenarios. The task also provided practical information on items related to CO{sub 2} storage applications in the Arches Province such as pressure buildup estimates, well spacing limitations, and injection field arrangements. The Arches Simulation project is a three-year effort and part of the United States Department of Energy (U.S. DOE)/National Energy Technology Laboratory (NETL) program on innovative and advanced technologies and protocols for monitoring/verification/accounting (MVA), simulation, and risk assessment of CO{sub 2} sequestration in geologic formations. The overall objective of the project is to develop a simulation framework for regional geologic CO{sub 2} storage infrastructure along the Arches Province of the Midwestern U.S.

  11. Towards practical implementation of computational solution of the Kinematic -wave Model for simulating traffic-flow scenarios

    E-Print Network [OSTI]

    Kumar, Nishant

    2004-11-15T23:59:59.000Z

    The Kinematic-wave model is one of the models proposed to simulate vehicular traffic. It has not received widespread use because of poor understanding of associated interface conditions and early use of incorrect numerical schemes used. This thesis...

  12. Numerical simulation of two-phase flow in discrete fractures using Rayleigh-Ritz finite element method

    E-Print Network [OSTI]

    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...

  13. A four-equation two-phase flow model for sodium boiling simulation of LMFBR fuel assemblies

    E-Print Network [OSTI]

    Schor, Andrei L.

    1982-01-01T23:59:59.000Z

    A three-dimensional numerical model for the simulation of sodium boiling transients has been developed. The model uses mixture mass and energy equations, while employing a separate momentum equation for each phase. Thermal ...

  14. Simulation of Strongly Heated Internal Gas Flows Using a Near-Wall Two-Equation Heat Flux Model

    SciTech Connect (OSTI)

    Richards, Adam H.; Spall, Robert E. [Utah State University, 1400 Old Main Hill Logan, Utah 84322-1400 (United States)

    2006-07-01T23:59:59.000Z

    A two-equation k-{omega} model is used to model a strongly heated, low-Mach number gas flowing upward in a vertical tube. Heating causes significant property variation and thickening of the viscous sublayer, consequently a fully developed flow does not evolve. Two-equation turbulence models generally perform poorly under such conditions. Consequently, in the present work, a near-wall two-equation heat transfer model is utilized in conjunction with the k-{omega} model to improve heat transfer predictions. (authors)

  15. Plane shear flows of frictionless spheres: Kinetic theory and 3D Soft-Sphere Discrete Element Method simulations

    E-Print Network [OSTI]

    Boyer, Edmond

    in the expression of the dissipation rate. We show that the Extended Kinetic Theory is in very good agreementPlane shear flows of frictionless spheres: Kinetic theory and 3D Soft-Sphere Discrete Element of spheres to evaluate the radial distribution function at contact that enables kinetic theory to correctly

  16. Development and verification of a numerical simulator to calculate the bottom hole flowing pressures in multiphase systems

    E-Print Network [OSTI]

    Rasool, Syed Ahmed

    1994-01-01T23:59:59.000Z

    the Middle East, but there were some wells located in offshore Louisiana. There was a wide range Of variation in the variables for each well, some of these were: flow rates, gas/oil ratios, total depths, tubing sizes, fluid Compositions, and water cuts...

  17. Numerical Simulation of Flow and Heat Transfer in Internal Multi-Pass Cooling Channel within Gas Turbine Blade

    E-Print Network [OSTI]

    Chu, Hung-Chieh 1979-

    2012-11-16T23:59:59.000Z

    four-pass channel with two different inlet settings. The main flowing channel was rectangular channel (AR=2:1) with hydraulic diameter (Dh ) equals to 2/3 inch (16.9 mm). The first and fourth channel were set as different aspect ratio (AR=2:1; AR=1...

  18. Low Speed Virtual Wind Tunnel Simulation For Educational Studies In Introducing Computational Fluid Dynamics And Flow Visualization

    E-Print Network [OSTI]

    Yang, Cher-Chiang

    2008-05-05T23:59:59.000Z

    ............................................................................................................... 25 3.2.4. Starting FlowLab ...................................................................................................................... 26 3.2.5. Geometry Settings... OF THE PROGRAMMING....................................................................... 52 v List of Figures FIGURE 2.1 ? COST AND TIME RELATIONSHIP WITH RESPECT TO CFD AND WIND TUNNELS............................. 5 FIGURE 2.2 - BOEING 777 DESIGN...

  19. Simulation of fluid flow mechanisms in high permeability zones (Super-K) in a giant naturally fractured carbonate reservoir

    E-Print Network [OSTI]

    Abu-Hassoun, Amer H.

    2009-05-15T23:59:59.000Z

    and fractures were treated as two systems. Reservoir management practices and decisions should be very carefully reviewed and executed in this dual continuum reservoir based on the results of this work. Studying this dual media flow behavior is vital for better...

  20. A Domain Decomposition Approach for Large-Scale Simulations of Flow Processes in Hydrate-Bearing Geologic Media

    SciTech Connect (OSTI)

    Zhang, Keni; Moridis, G.J.; Wu, Y.-S.; Pruess, K.

    2008-07-01T23:59:59.000Z

    Simulation of the system behavior of hydrate-bearing geologic media involves solving fully coupled mass- and heat-balance equations. In this study, we develop a domain decomposition approach for large-scale gas hydrate simulations with coarse-granularity parallel computation. This approach partitions a simulation domain into small subdomains. The full model domain, consisting of discrete subdomains, is still simulated simultaneously by using multiple processes/processors. Each processor is dedicated to following tasks of the partitioned subdomain: updating thermophysical properties, assembling mass- and energy-balance equations, solving linear equation systems, and performing various other local computations. The linearized equation systems are solved in parallel with a parallel linear solver, using an efficient interprocess communication scheme. This new domain decomposition approach has been implemented into the TOUGH+HYDRATE code and has demonstrated excellent speedup and good scalability. In this paper, we will demonstrate applications for the new approach in simulating field-scale models for gas production from gas-hydrate deposits.

  1. Numerical simulation of the non-isothermal developing flow of a nonlinear viscoelastic fluid in a rectangular channel

    E-Print Network [OSTI]

    Nikoleris, Teo

    1988-01-01T23:59:59.000Z

    Fluid in a Rectangular Channel (December 1988) Teo Nikoleris, B. S. , Reed College Chairman of Advisory Committee: Dr. R. Darby An orthogonal collocation finite element program was used to numerically model the hydrodynamicslly and thermally... in negligible increase of Nw~ ~?. Also, the approach of Chang and Finlayson [6], [7] who applied orthogonal collocation finite elements in conjunction with bicubic Hermitian polynomials to approximate various viscoelastic flow problems, also met with little...

  2. Dynamics and energetics of the cloudy boundary layer in simulations of off-ice flow in the marginal ice zone

    E-Print Network [OSTI]

    Harrington, Jerry Y.

    kinetic energy even in the present case where very strong surface heat fluxes occur. Ice-phase. Inclusion of the ice phase significantly affected the radiative budget as compared to purely liquid clouds, illustrating the importance of ice-phase­radiative couplings for accurate simulations of arctic clouds

  3. The impact of climate, CO2, nitrogen deposition and land use change on simulated contemporary global river flow

    E-Print Network [OSTI]

    Hoffman, Forrest M.

    The impact of climate, CO2, nitrogen deposition and land use change on simulated contemporary., 38, L08704, doi:10.1029/ 2011GL046773. 1. Introduction [2] Climate change and human activities and Fung [2008] found that climate and land use change play more important roles than the stomatal closure

  4. FRACSTIM/I: A Fully Coupled Fluid Flow/Heat Transport and Geomechanical Deformation/Fracture Generation Simulator

    Broader source: Energy.gov [DOE]

    This research will develop a fully coupled, fully implicit approach for EGS stimulation and reservoir simulation. Solve all governing equations simultaneously in fully implicit way. Enable massively parallel performance and scalability. Apply state of the art nonlinear PDE solvers: Jacobian Free Newton Krylov (JFNK) method.

  5. Simulations on the Nonlinear Mode Coupling in Multiple-scale Drift-type Turbulence with Coherent Flow Structures

    E-Print Network [OSTI]

    Lin, Zhihong

    coupling, the same back-action process can deform the spectral distribution in inertia range from the powerTH/2-31 Simulations on the Nonlinear Mode Coupling in Multiple-scale Drift-type Turbulence@energy.kyoto-u.ac.jp Abstract: The dynamics of secondary, anisotropic coherent structures behaving as a stationary wave

  6. BGSU Libraries STUDENT ASSISTANT

    E-Print Network [OSTI]

    Moore, Paul A.

    BGSU Libraries STUDENT ASSISTANT EMPLOYMENT APPLICATION NAME LIBRARY EXPERIENCE: LOCATION:________________________________________________________________________ ________________________________________________________________________________________________ OTHER OFFICE/LIBRARY SKILLS

  7. Executive Assistant to the Vice-President

    E-Print Network [OSTI]

    Michelson, David G.

    Administrative Assistant Murray Armstrong Administrative Assistant Tangerine Twiss Research Partnership

  8. USER’S GUIDE of TOUGH2-EGS-MP: A Massively Parallel Simulator with Coupled Geomechanics for Fluid and Heat Flow in Enhanced Geothermal Systems VERSION 1.0

    SciTech Connect (OSTI)

    Xiong, Yi [Colorado School of Mines; Fakcharoenphol, Perapon [Colorado School of Mines; Wang, Shihao [Colorado School of Mines; Winterfeld, Philip H. [Colorado School of Mines; Zhang, Keni [Lawrence Berkeley National Laboratory; Wu, Yu-Shu [Colorado School of Mines

    2013-12-01T23:59:59.000Z

    TOUGH2-EGS-MP is a parallel numerical simulation program coupling geomechanics with fluid and heat flow in fractured and porous media, and is applicable for simulation of enhanced geothermal systems (EGS). TOUGH2-EGS-MP is based on the TOUGH2-MP code, the massively parallel version of TOUGH2. In TOUGH2-EGS-MP, the fully-coupled flow-geomechanics model is developed from linear elastic theory for thermo-poro-elastic systems and is formulated in terms of mean normal stress as well as pore pressure and temperature. Reservoir rock properties such as porosity and permeability depend on rock deformation, and the relationships between these two, obtained from poro-elasticity theories and empirical correlations, are incorporated into the simulation. This report provides the user with detailed information on the TOUGH2-EGS-MP mathematical model and instructions for using it for Thermal-Hydrological-Mechanical (THM) simulations. The mathematical model includes the fluid and heat flow equations, geomechanical equation, and discretization of those equations. In addition, the parallel aspects of the code, such as domain partitioning and communication between processors, are also included. Although TOUGH2-EGS-MP has the capability for simulating fluid and heat flows coupled with geomechanical effects, it is up to the user to select the specific coupling process, such as THM or only TH, in a simulation. There are several example problems illustrating applications of this program. These example problems are described in detail and their input data are presented. Their results demonstrate that this program can be used for field-scale geothermal reservoir simulation in porous and fractured media with fluid and heat flow coupled with geomechanical effects.

  9. Three-dimensional numerical simulations of heat transfer in an annular fuel channel with periodic spacer ribs under a fully developed turbulent flow

    SciTech Connect (OSTI)

    Takase, Kazuyuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan)

    1997-05-01T23:59:59.000Z

    Thermal-hydraulic characteristics in a spacer-ribbed annular fuel channel for high-temperature gas-cooled reactors were analyzed numerically by three-dimensional computations under a fully developed turbulent flow. The two-equation {kappa}-{epsilon} turbulence model was applied in the present turbulent analysis, and the turbulence model constants for eddy viscosity and the turbulent Prandtl number were improved from the previous standard values to increase the accuracy of numerical simulations. Consequently, heat transfer coefficients and friction factors in the spacer-ribbed fuel channel were predicted with sufficient accuracy in the range of Reynolds number >3,000. It was clarified quantitatively that the main mechanism for heat transfer augmentation in the spacer-ribbed fuel channel was a combined effect of the turbulence promoter effect by the spacer rib and the velocity acceleration effect by a reduction in the channel cross section.

  10. assisted chemical separation: Topics by E-print Network

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

    We propose such as the ability to view flow fields and manipulate time-scales. The end result of this project will be studentsProject Team German Drazer, Assistant...

  11. assistance quarterly project: Topics by E-print Network

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

    We propose such as the ability to view flow fields and manipulate time-scales. The end result of this project will be studentsProject Team German Drazer, Assistant...

  12. Network Electricity Use Associated with Wireless Personal Digital Assistants

    E-Print Network [OSTI]

    Kammen, Daniel M.

    Network Electricity Use Associated with Wireless Personal Digital Assistants Jonathan Koomey1 the widely cited claim that the network electricity use associated with a wireless personal digital assistant PDA is equal to the electricity consumed by a refrigerator. It compiles estimates of the data flows

  13. Technology Assistance Program | Partnerships | ORNL

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

    Assistance Program SHARE Technology Assistance Program Electronics Research Assistance is available for small business licensees of ORNL technologies to leverage ORNL's expertise...

  14. Cooling Flows or Heating Flows?

    E-Print Network [OSTI]

    James Binney

    2003-10-08T23:59:59.000Z

    It is now clear that AGN heat cooling flows, largely by driving winds. The winds may contain a relativistic component that generates powerful synchrotron radiation, but it is not clear that all winds do so. The spatial and temporal stability of the AGN/cooling flow interaction are discussed. Collimation of the winds probably provides spatial stability. Temporal stability may be possible only for black holes with masses above a critical value. Both the failure of cooling flows to have adiabatic cores and the existence of X-ray cavities confirm the importance of collimated outflows. I quantify the scale of the convective flow that the AGN Hydra would need to drive if it balanced radiative inward flow by outward flow parallel to the jets. At least in Virgo any such flow must be confined to r<~20 kpc. Hydrodynamical simulations suggest that AGN outbursts cannot last longer than ~25 Myr. Data for four clusters with well studied X-ray cavities suggests that heating associated with cavity formation approximately balances radiative cooling. The role of cosmic infall and the mechanism of filament formation are briefly touched on.

  15. Multigrid and Krylov Solvers for Large Scale Finite Element Groundwater Flow Simulations on Distributed Memory Parallel Platforms

    SciTech Connect (OSTI)

    Mahinthakumar, K.

    1997-01-01T23:59:59.000Z

    In this report we present parallel solvers for large linear systems arising from the finite-element discretization of the three-dimensional steady-state groundwater flow problem. Our solvers are based on multigrid and Krylov subspace methods. The parallel implementation is based on a domain decomposition strategy with explicit message passing using NX and MPI libraries. We have tested our parallel implementations on the Intel Paragon XP/S 150 supercomputer using up to 1024 parallel processors and on other parallel platforms such as SGI/Power Challenge Array, Cray/SGI Origin 2000, Convex Exemplar SPP-1200, and IBM SP using up to 64 processors. We show that multigrid can be a scalable algorithm on distributed memory machines. We demonstrate the effectiveness of parallel multigrid based solvers by solving problems requiring more than 70 million nodes in less than a minute. This is more than 25 times faster than the diagonal preconditioned conjugate gradient method which is one of the more popular methods for large sparse linear systems. Our results also show that multigrid as a stand alone solver works best for problems with smooth coefficients, but for rough coefficients it is best used as a preconditioner for a Krylov subspace method such as the conjugate gradient method. We show that even for extremely heterogeneous systems the multigrid pre-conditioned conjugate gradient method is at least 10 times faster than the diagonally preconditioned conjugate gradient method.

  16. A Mixed Finite Element Framework for Modeling Coupled Fluid Flow ...

    E-Print Network [OSTI]

    Birendra Jha

    2005-10-03T23:59:59.000Z

    and in enhanced oil recovery techniques such as steam assisted gravity ..... When fluid flows through a porous medium there are three forces acting, per unit.

  17. Simulation effectively sites surge-relief facilities on Saudi pipeline

    SciTech Connect (OSTI)

    Dempsey, J.J.; Al-Gouhi, A.H. (Saudi Arabian Oil Co., Dhahrain (Saudi Arabia))

    1993-09-20T23:59:59.000Z

    Pipeline hydraulic and surge analysis studies of the Saudi Aramco East-West crude-oil pipeline assisted in expanding the system's capacity by 50%. Surge studies predicted that operational upsets, such as the trip of a pump station, cause excessive surge pressures in the pipeline system at new flow rates. Additional surge studies showed that surge-relief stations must be located downstream from each of six pump stations. The new surge-relief stations and an increase in capacity of existing surge-relief stations protect the pipelines at the higher flow rates. The paper describes modeling the system, the analysis of the hydraulics, surge analysis, acoustic transit times, relief valve simulation, surge-relief protection, surge-relief stations, station locations, simulation results, tank sizing, and valve testing.

  18. Assistance Focus: Africa (Brochure)

    SciTech Connect (OSTI)

    Not Available

    2014-12-01T23:59:59.000Z

    The Clean Energy Solutions Center Ask an Expert service connects governments seeking policy information and advice with one of more than 30 global policy experts who can provide reliable and unbiased quick-response advice and information. The service is available at no cost to government agency representatives from any country and the technical institutes assisting them. This publication presents summaries of assistance provided to African governments, including the benefits of that assistance.

  19. Monica Sasse Executive Assistant

    E-Print Network [OSTI]

    Vaswani, Namrata

    Swenson, Natalie Bryant, Allie Rowe Student Recruiting Sadie Johnson, Susie DeMoss Deb Dewall Assistant Institute Diane Meyer Pre-award Services Engineering Research Institute Engineering '("#)*(+#,)!-$.)/010

  20. Administrative Business Assistant

    E-Print Network [OSTI]

    Rock, Chris

    Center Marketing Raider Welcome Tech Activities Board Town & Gown BUSINESS OFFICE Associate Director Station Chief Financial O cer & Vice President for Administration and Finance (Clark) Interim Assistant

  1. DOE Technical Assistance Program

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

    Designing Effective Residential Retrofit Programs eere.energy.gov The Parker Ranch installation in Hawaii DOE Technical Assistance Program Quality Assurance for Residential...

  2. Radiological Assistance Program

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    1992-04-10T23:59:59.000Z

    To establish Department of Energy (DOE) policy, procedures, authorities, and responsibilities for its Radiological Assistance Program. Canceled by DOE O 153.1.

  3. Brownfield Assistance Program (Delaware)

    Broader source: Energy.gov [DOE]

    The Brownfield Assistance Program, administrated by the Delaware Economic Development Office (DEDO) and funded from Delaware Strategic Fund, provides matching grants to owners and developers to...

  4. Improving parameter estimation and water table depth simulation in a land surface model using GRACE water storage and estimated base flow data

    E-Print Network [OSTI]

    Lo, Min-Hui; Famiglietti, James S; Yeh, P. J.-F.; Syed, T. H

    2010-01-01T23:59:59.000Z

    40, doi:10.1175/2008JHM993.1. Szilagyi, J. (2004), Heuristicsimulations of base flow [Szilagyi, 2004]. Although the

  5. TMVOC, simulator for multiple volatile organic chemicals

    SciTech Connect (OSTI)

    Pruess, Karsten; Battistelli, Alfredo

    2003-03-25T23:59:59.000Z

    TMVOC is a numerical simulator for three-phase non-isothermal flow of water, soil gas, and a multicomponent mixture of volatile organic chemicals (VOCs) in multidimensional heterogeneous porous media. It is an extension of the TOUGH2 general-purpose simulation program developed at the Lawrence Berkeley National Laboratory. TMVOC is designed for applications to contamination problems that involve hydrocarbon fuel or organic solvent spills in saturated and unsaturated zones. It can model contaminant behavior under ''natural'' environmental conditions, as well as for engineered systems, such as soil vapor extraction, groundwater pumping, or steam-assisted source remediation. TMVOC is upwards compatible with T2VOC (Falta et al., 1995) and can be initialized from T2VOC-style initial conditions. The main enhancements in TMVOC relative to T2VOC are as follows: a multicomponent mixture of volatile organic chemicals can be modeled; any and all combinations of the three phases water-oil-gas are treated; several non-condensible gases may be present; diffusion is treated in all phases in a manner that is fully coupled with phase partitioning. This paper gives a brief summary of the methodology used in TMVOC as well as highlighting some implementation issues. Simulation of a NAPL spill and subsequent remediation is discussed for a 2-D vertical section of a saturated-unsaturated flow problem.

  6. Mexico Small Business Assistance fest

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

    celebrate success at New Mexico Small Business Assistance fest April 4, 2011 LOS ALAMOS, New Mexico, April 4, 2011-The New Mexico Small Business Assistance (NMSBA) program is...

  7. Weatherization Assistance Program Technical Assistance Center

    SciTech Connect (OSTI)

    Robert Adams

    2009-01-07T23:59:59.000Z

    The following is a synopsis of the major achievements attributed to the operation of the Weatherization Assistance Program Technical Assistance Center (WAPTAC) by the National Association for State Community Services Programs (NASCSP). During the past five years, the WAPTAC has developed into the premier source for information related to operating the Weatherization Assistance Program (WAP) at the state and local levels. The services provide through WAPTAC include both virtual technical support as well as hands-on training and instruction in classroom and in the field. The WAPTAC achieved several important milestones during its operation including the establishment of a national Weatherization Day now celebrated in most states, the implementation of a comprehensive Public Information Campaign (PIC) to raise the awareness of the Program among policy makers and the public, the training of more than 150 new state managers and staff as they assume their duties in state offices around the country, and the creation and support of a major virtual information source on the Internet being accessed by thousands of staff each month. The Weatherization Assistance Program Technical Assistance Center serves the Department of Energy's (DOE) Office of Weatherization and Intergovernmental Program as a valuable training and technical assistance resource for the network of 54 direct state grantees (50 states, District of Columbia and three Native American tribes) and the network of 900 local subgrantees (comprised of community action agencies, units of local government, and other non-profit organizations). The services provided through WAPTAC focus on standardizing and improving the daily management of the WAP. Staff continually identify policies changes and best practices to help the network improve its effectiveness and enhance the benefits of the Program for the customers who receive service and the federal and private investors. The operations of WAPTAC are separated into six distinct areas: (1) Orientation for New WAP State Directors and Staff; (2) Pollution Occurrence Insurance Project; (3) Public Information Campaign; (4) State Management Training Project; (5) System for Integrating and Reviewing Technologies and Techniques; and (6) WAPTAC Services.

  8. Knowledge Assisted Visualization Knowledge-assisted visualization of seismic data

    E-Print Network [OSTI]

    for knowledge-assisted annotation and computer-assisted interpretation of seismic data for oil and gas, using seismic interpretation, is performed that makes it fit very naturally into the paradigmKnowledge Assisted Visualization Knowledge-assisted visualization of seismic data Daniel Patel a

  9. Assisting Difficult Calving

    E-Print Network [OSTI]

    Faries Jr., Floron C.

    2006-12-20T23:59:59.000Z

    Calving difficulty is frequently caused by disproportionate size--the calf is too big for the birth canal. This publication discusses the stages of labor, how to assist in delivery and what to do after the delivery of a calf....

  10. 9003: Biorefinery Assistance Program

    Broader source: Energy.gov [DOE]

    Breakout Session 1D—Building Market Confidence and Understanding I: Integrated Biorefinery (Lessons Learned and Best Practices) 9003: Biorefinery Assistance Program Chris Cassidy, National Business Renewable Energy Advisor, U.S. Department of Agriculture

  11. DOE Technical Assistance Program

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

    Solid-State Solutions for Municipal Lighting: What You'll Need to Know eere.energy.gov The Parker Ranch installation in Hawaii DOE Technical Assistance Program Solid-State...

  12. Dr. Krisellen Maloney Assistant Dean for

    E-Print Network [OSTI]

    Dodla, Ramana

    Assistant I Esmeralda Huerta Vacant Library Services Assistant I Timothy Lefkowitz Vacant Library Services

  13. A Simulator with Numerical Upscaling for the Analysis of Coupled Multiphase Flow and Geomechanics in Heterogeneous and Deformable Porous and Fractured Media

    E-Print Network [OSTI]

    Yang, Daegil

    2013-07-15T23:59:59.000Z

    A growing demand for more detailed modeling of subsurface physics as ever more challenging reservoirs - often unconventional, with significant geomechanical particularities - become production targets has moti-vated research in coupled flow...

  14. Mutiscale Modeling of Segregation in Granular Flows

    SciTech Connect (OSTI)

    Jin Sun

    2007-08-03T23:59:59.000Z

    Modeling and simulation of segregation phenomena in granular flows are investigated. Computational models at different scales ranging from particle level (microscale) to continuum level (macroscale) are employed in order to determine the important microscale physics relevant to macroscale modeling. The capability of a multi-fluid model to capture segregation caused by density difference is demonstrated by simulating grain-chaff biomass flows in a laboratory-scale air column and in a combine harvester. The multi-fluid model treats gas and solid phases as interpenetrating continua in an Eulerian frame. This model is further improved by incorporating particle rotation using kinetic theory for rapid granular flow of slightly frictional spheres. A simplified model is implemented without changing the current kinetic theory framework by introducing an effective coefficient of restitution to account for additional energy dissipation due to frictional collisions. The accuracy of predicting segregation rate in a gas-fluidized bed is improved by the implementation. This result indicates that particle rotation is important microscopic physics to be incorporated into the hydrodynamic model. Segregation of a large particle in a dense granular bed of small particles under vertical. vibration is studied using molecular dynamics simulations. Wall friction is identified as a necessary condition for the segregation. Large-scale force networks bearing larger-than-average forces are found with the presence of wall friction. The role of force networks in assisting rising of the large particle is analyzed. Single-point force distribution and two-point spatial force correlation are computed. The results show the heterogeneity of forces and a short-range correlation. The short correlation length implies that even dense granular flows may admit local constitutive relations. A modified minimum spanning tree (MST) algorithm is developed to asymptotically recover the force statistics in the force networks. This algorithm provides a possible route to constructing a continuum model with microstructural information supplied from it. Microstructures in gas fluidized beds are also analyzed using a hybrid method, which couples the discrete element method (DEM) for particle dynamics with the averaged two-fluid (TF) equations for the gas phase. Multi-particle contacts are found in defluidized regions away from bubbles in fluidized beds. The multi-particle contacts invalidate the binary-collision assumption made in the kinetic theory of granular flows for the defluidized regions. Large ratios of contact forces to drag forces are found in the same regions, which confirms the relative importance of contact forces in determining particle dynamics in the defluidized regions.

  15. An Efficient, Semi-implicit Pressure-based Scheme Employing a High-resolution Finitie Element Method for Simulating Transient and Steady, Inviscid and Viscous, Compressible Flows on Unstructured Grids

    SciTech Connect (OSTI)

    Richard C. Martineau; Ray A. Berry

    2003-04-01T23:59:59.000Z

    A new semi-implicit pressure-based Computational Fluid Dynamics (CFD) scheme for simulating a wide range of transient and steady, inviscid and viscous compressible flow on unstructured finite elements is presented here. This new CFD scheme, termed the PCICEFEM (Pressure-Corrected ICE-Finite Element Method) scheme, is composed of three computational phases, an explicit predictor, an elliptic pressure Poisson solution, and a semiimplicit pressure-correction of the flow variables. The PCICE-FEM scheme is capable of second-order temporal accuracy by incorporating a combination of a time-weighted form of the two-step Taylor-Galerkin Finite Element Method scheme as an explicit predictor for the balance of momentum equations and the finite element form of a time-weighted trapezoid rule method for the semi-implicit form of the governing hydrodynamic equations. Second-order spatial accuracy is accomplished by linear unstructured finite element discretization. The PCICE-FEM scheme employs Flux-Corrected Transport as a high-resolution filter for shock capturing. The scheme is capable of simulating flows from the nearly incompressible to the high supersonic flow regimes. The PCICE-FEM scheme represents an advancement in mass-momentum coupled, pressurebased schemes. The governing hydrodynamic equations for this scheme are the conservative form of the balance of momentum equations (Navier-Stokes), mass conservation equation, and total energy equation. An operator splitting process is performed along explicit and implicit operators of the semi-implicit governing equations to render the PCICE-FEM scheme in the class of predictor-corrector schemes. The complete set of semi-implicit governing equations in the PCICE-FEM scheme are cast in this form, an explicit predictor phase and a semi-implicit pressure-correction phase with the elliptic pressure Poisson solution coupling the predictor-corrector phases. The result of this predictor-corrector formulation is that the pressure Poisson equation in the PCICE-FEM scheme is provided with sufficient internal energy information to avoid iteration. The ability of the PCICE-FEM scheme to accurately and efficiently simulate a wide variety of inviscid and viscous compressible flows is demonstrated here.

  16. Technical Assistance to Developers

    SciTech Connect (OSTI)

    Rockward, Tommy [Los Alamos National Laboratory; Borup, Rodney L. [Los Alamos National Laboratory; Garzon, Fernando H. [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory; Spernjak, Dusan [Los Alamos National Laboratory

    2012-07-17T23:59:59.000Z

    This task supports the allowance of technical assistance to fuel-cell component and system developers as directed by the DOE. This task includes testing of novel materials and participation in the further development and validation of single cell test protocols. This task also covers technical assistance to DOE Working Groups, the U.S. Council for Automotive Research (USCAR) and the USCAR/DOE Driving Research and Innovation for Vehicle efficiency and Energy sustainability (U.S. Drive) Fuel Cell Technology Team. Assistance includes technical validation of new fuel cell materials and methods, single cell fuel cell testing to support the development of targets and test protocols, and regular advisory participation in other working groups and reviews. This assistance is made available to PEM fuel cell developers by request and DOE Approval. The objectives are to: (1) Support technically, as directed by DOE, fuel cell component and system developers; (2) Assess fuel cell materials and components and give feedback to developers; (3) Assist the DOE Durability Working Group with the development of various new material durability Testing protocols; and (4) Provide support to the U.S. Council for Automotive Research (USCAR) and the USCAR/DOE Fuel Cell Technology Team. FY2012 specific technical objectives are: (1) Evaluate novel MPL materials; (2) Develop of startup/ shutdown protocol; (3) Test the impact of hydrophobic treatment on graphite bi-polar plates; (4) Perform complete diagnostics on metal bi-polar plates for corrosion; and (5) Participate and lead efforts in the DOE Working Groups.

  17. THE APPLICATION OF A STATISTICAL DOWNSCALING PROCESS TO DERIVE 21{sup ST} CENTURY RIVER FLOW PREDICTIONS USING A GLOBAL CLIMATE SIMULATION

    SciTech Connect (OSTI)

    Werth, D.; Chen, K. F.

    2013-08-22T23:59:59.000Z

    The ability of water managers to maintain adequate supplies in coming decades depends, in part, on future weather conditions, as climate change has the potential to alter river flows from their current values, possibly rendering them unable to meet demand. Reliable climate projections are therefore critical to predicting the future water supply for the United States. These projections cannot be provided solely by global climate models (GCMs), however, as their resolution is too coarse to resolve the small-scale climate changes that can affect hydrology, and hence water supply, at regional to local scales. A process is needed to ‘downscale’ the GCM results to the smaller scales and feed this into a surface hydrology model to help determine the ability of rivers to provide adequate flow to meet future needs. We apply a statistical downscaling to GCM projections of precipitation and temperature through the use of a scaling method. This technique involves the correction of the cumulative distribution functions (CDFs) of the GCM-derived temperature and precipitation results for the 20{sup th} century, and the application of the same correction to 21{sup st} century GCM projections. This is done for three meteorological stations located within the Coosa River basin in northern Georgia, and is used to calculate future river flow statistics for the upper Coosa River. Results are compared to the historical Coosa River flow upstream from Georgia Power Company’s Hammond coal-fired power plant and to flows calculated with the original, unscaled GCM results to determine the impact of potential changes in meteorology on future flows.

  18. Investigating Flow-Structure Interactions in Cerebral Aneurysms...

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

    Investigating Flow-Structure Interactions in Cerebral Aneurysms Share Topic Programs Mathematics, computing, & computer science Modeling, simulation, & visualization...

  19. Low Income Home Energy Assistance Program (LIHEAP)

    Broader source: Energy.gov [DOE]

    The Low Income Home Energy Assistance Program (LIHEAP) provides resources to assist families with energy costs. This federally funded assistance helps in managing costs associated with:

  20. Renewable Energy Project Assistance | Department of Energy

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

    Assistance Renewable Energy Project Assistance The Federal Energy Management Program (FEMP) provides renewable energy project assistance to help Federal agencies identify and...

  1. Previous Technical Assistance | Department of Energy

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

    Technical assistance provided to WGAWIEB by the Electricity Market Studies Group of LBNL and The Regulatory Assistance Project (RAP); and More limited technical assistance...

  2. Flow instabilities in the core and the coolant circuit of advances low-boiling light water reacto: classification of causes and development of simulator for the future analysis

    E-Print Network [OSTI]

    Rezvyi, Aleksey

    2002-01-01T23:59:59.000Z

    . . 1. 3. Analysis method determination. 2. THEORETICAL ASPECTS OF DIFFERENT TYPES OF THE THERMO-HYDRAULIC INSTABILITIES. . 2. 1. Static instability of loading charactenstic. . . . . . . . . . . . . . . . . . . . . . . 2. 2. Resonance instability... in the 1C L-BWR during heat-up process. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Diagram of components hierarchy of the Thermo-Hydraulic instabilities phenomenon. . The steam generating heating channels instability area, mass flow vs...

  3. Appendixes 159 160 Simulation of Ground-Water/Surface-Water Flow in the Santa ClaraCalleguas Ground-Water Basin, Ventura County, California

    E-Print Network [OSTI]

    ­Calleguas Ground-Water Basin, Ventura County, California APPENDIX 1: DOCUMENTATION AND DESCRIPTION OF THE DIGITAL-Water/Surface-Water Flow in the Santa Clara­Calleguas Ground-Water Basin, Ventura County, California Figure A.1.2. Location-Water Basin, Ventura County, California Figure A1.4. Location of USGS_GWMODEL coverage. PacificOcean VENTURACO

  4. Medical Robots Surgical Assistants

    E-Print Network [OSTI]

    Pulfrey, David L.

    1 Medical Robots Surgical Assistants · Efficacy of Procedure ­ Accuracy ­ Longevity ­ Invasiveness · Augment human capabilities ­ Enabling new procedures ­ Time under anaesthetic #12;2 Surgical Robots) ­ Sensei (Hansen Medical) Autonomous Surgical Robots Robodoc.com #12;3 Guided Surgical Robots Makosurgical

  5. About Technical Assistance

    Broader source: Energy.gov [DOE]

    As technologies proceed along the development pipeline, most face major hurdles as they attempt to enter commercial markets. Our Technical Assistance program helps lower a range of institutional barriers to prepare innovative, energy-efficient technologies and energy management systems for full commercial deployment. These projects and activities address barriers that are not technical, Technology Readiness Level 9.

  6. Administrative Business Assistant

    E-Print Network [OSTI]

    Rock, Chris

    Marketing Raider Welcome Tech Activities Board Town & Gown BUSINESS OFFICE Associate Director for Business Legal Services University ID Center University Police SUB Station Interim Chief Financial O cer & Vice IT Student Assistant (2) Interim Chief Financial O cer & Vice President for Administration and Finance (Sloan

  7. Anantha Aiyyer Assistant Professor

    E-Print Network [OSTI]

    Parker, Matthew D. Brown

    radiant energy over earth's surface Graphics source: Georgia Tech. Univ. 12 Solar energy received at any or rainfall amount is broken. Thus, even in a relatively cold climate, we can expect a heat wave or a record4/13/2011 1 Anantha Aiyyer Assistant Professor Marine, Earth and Atmospheric Sciences 1 Climate

  8. Office of Security Assistance

    Broader source: Energy.gov [DOE]

    The Office of Security Assistance manages the Technology Deployment Program to improve the security posture of the Department of Energy and the protection of its assets and facilities through the deployment of new safeguards and security technologies and development of advanced technologies that reduce operating costs, save protective force lives, and improve security effectiveness.

  9. Archives Research Assistant Classification: Student Assistant 3 (LSA 3)

    E-Print Network [OSTI]

    Archives Research Assistant Classification: Student Assistant 3 (LSA 3) Salary: $9.50 - $9.69 Hours: 15-20 per week The University of Oregon Libraries invites application for a part-time, temporary Archives Research Assistant in Knight Library's Special Collections and University Archives. The student

  10. Job Training Assistance Programs (Tennessee)

    Broader source: Energy.gov [DOE]

    The Job Training Assistance Programs in Tennessee are a combination of three programs: The FastTrack Job Training Assistance Program (FJTAP), The Tennessee Job Skills Program (TJS), and The Job...

  11. Microblower assisted barometric valve

    SciTech Connect (OSTI)

    Rossabi, Joseph; Hyde, Warren K.; Riha, Brian D.; Jackson, Dennis G.; Sappington, Frank

    2005-12-06T23:59:59.000Z

    A gas exchange apparatus is provided which provides for both passive fluid flow and blower associated fluid flow through a barometric valve. A battery powered blower is provided which allows for operation of the barometric valve during times when the barometric valve would otherwise be closed, and provides for enhanced volume of gas exchange.

  12. Numerical simulation of the air flow field in a laboratory fume hood using the CFD-ACE(TM) computational fluid dynamics code

    E-Print Network [OSTI]

    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...

  13. Powder Flow Testing with 2D and 3D Biaxial and Triaxial simulations C. T. David, R. Garca-Rojo, H. J. Herrmann, S. Luding (*)

    E-Print Network [OSTI]

    Luding, Stefan

    , adhesion/cohesion and Coulomb friction are implemented in more advanced models. In both experiments Prof. Brian Scarlett ABSTRACT The mechanical response of frictional powders under quasi-static loading but more studies are needed to identify them properly. KEYWORDS: Particle simulation, friction, creep

  14. Electrically-Assisted Diesel Particulate Filter Regeneration...

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

    More Documents & Publications Substrate Studies of an Electrically-Assisted Diesel Particulate Filter Electrically-Assisted Diesel Particulate Filter Regeneration...

  15. Laser-assisted electrochemistry

    SciTech Connect (OSTI)

    Glenn, D.F.

    1995-05-01T23:59:59.000Z

    The effect of laser irradiation on electrodeposition processes has been investigated. These studies demonstrated that the addition of laser irradiation to an electroplating process can dramatically enhance plating rates and current efficiencies, as well as improve the morphology of the resultant electrodeposit. During the course of these investigations, the mechanism for the laser enhancement of electrodeposition processes was determined. Experimental evidence was obtained to show that laser irradiation of the substrate results in increased metal ion concentrations at the surface of the electrode due to a laser-induced Soret effect. The laser-induced Soret effect has important implications for laser-assisted electrochemical processing. The increase in the surface concentration of ions allows efficient electrodeposition from dilute solutions. As such, laser- assisted electrodeposition may develop into an environmentally conscious manufacturing process by reducing waste and limiting worker exposure to toxic chemicals.

  16. In Vitro Evaluation of Multiobjective Hemodynamic Control of a Heart-Assist Pump

    E-Print Network [OSTI]

    Paden, Brad

    In Vitro Evaluation of Multiobjective Hemodynamic Control of a Heart-Assist Pump KWAN-WOONG GWAK§ Ventricular assist devices now clinically used for treatment of end-stage heart failure require responsive simulator using a HeartQuest centrifugal blood pump (CF4b, MedQuest Products, Salt Lake City, UT). To avoid

  17. Improved Steam Assisted Gravity Drainage (SAGD) Performance with Solvent as Steam Additive

    E-Print Network [OSTI]

    Li, Weiqiang

    2011-02-22T23:59:59.000Z

    Steam Assisted Gravity Drainage (SAGD) is used widely as a thermal recovery technique in Canada to produce a very viscous bitumen formation. The main research objectives of this simulation and experimental study are to investigate oil recovery...

  18. Non-thermal plasma-assisted NOx reduction over Na-Y zeolites...

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

    investigated in the non-thermal plasma assisted NOx reduction reaction using a simulated diesel engine exhaust gas mixture. The acid sites were formed by NH4+ ion exchange and...

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

    E-Print Network [OSTI]

    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...

  20. Impact assisted segmented cutterhead

    DOE Patents [OSTI]

    Morrell, Roger J. (Bloomington, MN); Larson, David A. (Minneapolis, MN); Ruzzi, Peter L. (Eagan, MN)

    1992-01-01T23:59:59.000Z

    An impact assisted segmented cutterhead device is provided for cutting various surfaces from coal to granite. The device comprises a plurality of cutting bit segments deployed in side by side relationship to form a continuous cutting face and a plurality of impactors individually associated with respective cutting bit segments. An impactor rod of each impactor connects that impactor to the corresponding cutting bit segment. A plurality of shock mounts dampening the vibration from the associated impactor. Mounting brackets are used in mounting the cutterhead to a base machine.

  1. Expert assistants for design

    SciTech Connect (OSTI)

    Aldridge, J.; Cerutti, J.; Draisin, W.; Steuerwalt, M.

    1986-01-01T23:59:59.000Z

    Two expert programs currently under development at the Los Alamos National Laboratory, PROCON and the Designer's Apprentice, are briefly described. Both codes define interface to simulations that provide a wide variety of information about the performance of complex devices. (BCS)

  2. Transportation Economic Assistance Program (Wisconsin)

    Broader source: Energy.gov [DOE]

    The Transportation Economic Assistance Program provides state grants to private business and local governments to improve transportation to projects improving economic conditions and creating or...

  3. New Mexico Small Business Assistance

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

    of Los Alamos, Sandia national laboratories LOS ALAMOS, NEW MEXICO, May 31, 2012-The New Mexico Small Business Assistance (NMSBA) program, a collaboration of Los Alamos National...

  4. OFFICE OF PROCUREMENT & ASSISTANCE MANAGEMENT

    Energy Savers [EERE]

    & ASSISTANCE MANAGEMENT INHERENTLY GOVERNMENTAL AND COMMERCIAL ACTIVITIES (IGCA) INVENTORY GUIDANCE 2012 Name Date Tel E-Mail Created by: Jeff Davis March 28, 2012...

  5. DOE and NREL Technical Assistance

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

    assistance to Greensburg, Kansas, in the following areas. MASTER PLAN FOR REBUILDING GREEN * Completed detailed studies on renewable energy sources, cost-effective energy...

  6. CFD analysis of laminar oscillating flows

    SciTech Connect (OSTI)

    Booten, C. W. Charles W.); Konecni, S. (Snezana); Smith, B. L. (Barton L.); Martin, R. A. (Richard A.)

    2001-01-01T23:59:59.000Z

    This paper describes a numerical simulations of oscillating flow in a constricted duct and compares the results with experimental and theoretical data. The numerical simulations were performed using the computational fluid dynamics (CFD) code CFX4.2. The numerical model simulates an experimental oscillating flow facility that was designed to test the properties and characteristics of oscillating flow in tapered ducts, also known as jet pumps. Jet pumps are useful devices in thermoacoustic machinery because they produce a secondary pressure that can counteract an unwanted effect called streaming, and significantly enhance engine efficiency. The simulations revealed that CFX could accurately model velocity, shear stress and pressure variations in laminar oscillating flow. The numerical results were compared to experimental data and theoretical predictions with varying success. The least accurate numerical results were obtained when laminar flow approached transition to turbulent flow.

  7. Development and validation of a radial inflow turbine model for simulation of the SNL S-CO2 split-flow loop.

    SciTech Connect (OSTI)

    Vilim, R. B. (Nuclear Engineering Division)

    2012-07-31T23:59:59.000Z

    A one-dimensional model for a radial inflow turbine has been developed for super-critical carbon dioxide (S-CO{sub 2}) Brayton cycle applications. The model accounts for the main phenomena present in the volute, nozzle, and impeller of a single-stage turbine. These phenomena include internal losses due to friction, blade loading, and angle of incidence and parasitic losses due to windage and blade-housing leakage. The model has been added as a component to the G-PASS plant systems code. The model was developed to support the analysis of S-CO{sub 2} cycles in conjunction with small-scale loop experiments. Such loops operate at less than a MWt thermal input. Their size permits components to be reconfigured in new arrangements relatively easily and economically. However, the small thermal input combined with the properties of carbon dioxide lead to turbomachines with impeller diameters of only one to two inches. At these sizes the dominant phenomena differ from those in larger more typical machines. There is almost no treatment in the literature of turbomachines at these sizes. The present work therefore is aimed at developing turbomachine models that support the task of S-CO{sub 2} cycle analysis using small-scale tests. Model predictions were compared against data from an experiment performed for Sandia National Laboratories in the split-flow Brayton cycle loop currently located at Barber-Nichols Inc. The split-flow loop incorporates two turbo-alternator-compressor (TAC) units each incorporating a radial inflow turbine and a radial flow compressor on a common shaft. The predicted thermodynamic conditions at the outlet of the turbine on the main compressor shaft were compared with measured values at different shaft speeds. Two modifications to the original model were needed to better match the experiment data. First, a representation of the heat loss from the volute downstream of the sensed inlet temperature was added. Second, an empirical multiplicative factor was applied to the Euler head and another to the head loss to bring the predicted outlet pressure into better agreement with the experiment. These changes also brought the overall efficiency of the turbine into agreement with values cited by Barber Nichols for small turbines. More generally, the quality of measurement set data can in the future be improved by additional steps taken in the design and operation of the experimental apparatus. First, a thermocouple mounted at the nozzle inlet would provide a better indication of temperature at this key point. Second, heat losses from the turbine should be measured directly. Allowing the impeller to free wheel at inlet conditions and measuring the temperature drop between inlet and outlet would provide a more accurate measure of heat loss. Finally, the enthalpy change during operation is more accurately obtained by measuring the torque on the stator using strain gauges rather than by measuring pressure and temperature at inlet and outlet to infer thermodynamic states.

  8. Mathematical and experimental modelling of heat pump assisted microwave drying

    SciTech Connect (OSTI)

    Xiguo Jia (Univ. of Queensland (Australia))

    1993-01-01T23:59:59.000Z

    Drying is one of the most energy intensive operations in industry and agriculture. In the quest to increase drying efficiency and product quality, new technologies and methods are constantly being sought. Of these technologies, heat pump assisted drying and microwave drying have proved to be the most promising contenders. In order to achieve a better understanding and provide a computer design tool for heat pump assisted convective and microwave drying, both mathematical modelling and experimental investigations of heat pump assisted microwave dryers have been undertaken in this study. A mathematical model has been developed to predict the steady-state performance of a heat pump assisted continuous microwave dryer, with emphasis on the simulation of heat and mass transfer processes in the evaporator and drying chamber. The model is intend to serve as a design tool in the study of heat pump dryers. To achieve the optimum design, the influences of the key design and operating parameters, as well as the comparison of different drying configurations, have been examined. Based on investigation results, several methods have been proposed to improve the performance of heat pump assisted microwave drying, such as the use of a recuperator. To validate the above mathematical model, extensive drying tests using foam rubber as the test material have been conducted on a prototype heat pump assisted microwave dryer. The prototype heat pump input power was 5 kW with a maximum microwave input power of 10 kW. The experimental performance data confirmed the veracity of the simulation model. The experimental results on drying test materials indicate that with careful design heat pump assisted microwave drying is comparable to convective drying in energy consumption while with a much higher drying speed.

  9. Strategy for quantum algorithm design assisted by machine learning

    E-Print Network [OSTI]

    Jeongho Bang; Junghee Ryu; Seokwon Yoo; Marcin Pawlowski; Jinhyoung Lee

    2014-07-17T23:59:59.000Z

    We propose a method for quantum algorithm design assisted by machine learning. The method uses a quantum-classical hybrid simulator, where a "quantum student" is being taught by a "classical teacher." In other words, in our method, the learning system is supposed to evolve into a quantum algorithm for a given problem assisted by classical main-feedback system. Our method is applicable to design quantum oracle-based algorithm. As a case study, we chose an oracle decision problem, called a Deutsch-Jozsa problem. We showed by using Monte-Carlo simulations that our simulator can faithfully learn quantum algorithm to solve the problem for given oracle. Remarkably, learning time is proportional to the square root of the total number of parameters instead of the exponential dependance found in the classical machine learning based method.

  10. Status of the ground water flow model for the UMTRA Project, Shiprock, New Mexico, site

    SciTech Connect (OSTI)

    Not Available

    1995-01-01T23:59:59.000Z

    A two-dimensional numerical model was constructed for the alluvial aquifer in the area of the Uranium Mill Tailings Remedial Action (UMTRA) Project Shiprock, New Mexico, site. This model was used to investigate the effects of various hydrologic parameters on the evolution of the ground water flow field. Results of the model are useful for defining uncertainties in the site conceptual model and suggesting data collection efforts to reduce these uncertainties. The computer code MODFLOW was used to simulate the two-dimensional flow of ground water in the alluvium. The escarpment was represented as a no-flow boundary. The San Juan River was represented with the MODFLOW river package. A uniform hydraulic conductivity distribution with the value estimated by the UMTRA Project Technical Assistance Contractor (TAC) and a uniform recharge distribution was used. Infiltration from the flowing artesian well was represented using the well package. The ground water flow model was calibrated to ground water levels observed in April 1993. Inspection of hydrographs shows that these levels are representative of typical conditions at the site.

  11. The verification of a semi-analytical reservoir simulator using a finite difference reservoir simulator 

    E-Print Network [OSTI]

    Dube, Hans Gerhardt

    1990-01-01T23:59:59.000Z

    of Cases Fundamental Difference Between the Reservoir Simulators. Data Sets. . General Process of Verification. . . . . . . . . . . . . . . 22 24 25 25 26 29 32 36 SINGLE LAYER, RADIAL FLOW DRAWDOWN CASES. . 38 viii Page Infinite Cylindrical... Drawdown Problems. . . . . . . . . . . . . 38 41 43 45 49 50 52 MULTIPLE LAYER RESERVOIR, RADIAL FLOW DRAWDOWN CASES. 63 Simulation of Multiple Layer Reservoirs. . . . . . Simulation Parameters. Constant Rate Drawdown Tests in an Infinite...

  12. Proof-assistants using Dependent Type Henk Barendregt

    E-Print Network [OSTI]

    Barendregt, Henk

    .3 Autarkic Computations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 5 Proof assistants

  13. Laser Assisted Emittance Exchange

    SciTech Connect (OSTI)

    Xiang, Dao; /SLAC

    2012-06-11T23:59:59.000Z

    We describe here the laser assisted emittance exchange (LAEE) technique. A laser operating in the transverse mode (TEM10 or TEM01) is used to interact with the electron beam in a dispersive region and to initiate the transverse-to-longitudinal emittance exchange. It is shown that with the LAEE one can generate an electron beam with ultralow transverse emittance, which allows one to significantly bring down the size of an X-ray free electron laser (FEL) and greatly extend the availability of these light sources. The technique can also be used to enhance the performances of X-ray FELs in storage rings. The timing and energy jitter problems for the standard emittance exchange and LAEE techniques are also discussed.

  14. A Bicycle Electric Assist Unit

    E-Print Network [OSTI]

    Petron, Arthur J

    2010-01-01T23:59:59.000Z

    The BEAU is an electric-assist bicycle system that is completely self-contained within the rear wheel. The purpose of approaching a electric-assist bicycle in this manner is two-fold: simplifying the device and opening the ...

  15. Visualization of groundwater flow using line integral convolution

    E-Print Network [OSTI]

    Andrzejak, Artur

    for the simulation of groundwater flow and transport models. INTRODUCTION Nowadays, 3D numerical simulationsVisualization of groundwater flow using line integral convolution JÃ?RG GOTTHARDT & CAROLA BLÃ?MER of groundwater flow and transport problems become more and more common. At the same time the need for adequate

  16. Imbibition assisted oil recovery

    E-Print Network [OSTI]

    Pashayev, Orkhan H.

    2004-11-15T23:59:59.000Z

    as two superimposed continuous porous media. In the dual porosity model, the fluid flow between the matrix blocks and the surrounding fractures is characterized by the transfer functions. For the transfer functions, it is a prerequisite.... 1.2 Capillary Imbibition Capillary imbibition is described as a spontaneous penetration of a wetting phase into a porous media while displacing a non-wetting phase by means of capillary pressure, e.g., water imbibing into an oil-saturated rock...

  17. WANTED: Undergraduate Research Assistant Betelgeuse's Molecular Inventory

    E-Print Network [OSTI]

    Harper, Graham

    WANTED: Undergraduate Research Assistant Betelgeuse's Molecular Inventory GHRS Pre-COSTAR LSA G140L Assistant Opportunity We are seeking an undergraduate research assistant to help make an inventory

  18. Clinical Assistant Professor Human Resource Development

    E-Print Network [OSTI]

    Clinical Assistant Professor Human Resource Development Texas A&M University's Department, seeks a Clinical Assistant Professor of Human Resource Development with emphasis in Technology Management. This individual will assume the duties typically expected of a Clinical Assistant Professor

  19. GRADUATE COLLEGE TERMINATION OF GRADUATE ASSISTANT

    E-Print Network [OSTI]

    Cho, Hokwon

    GRADUATE COLLEGE TERMINATION OF GRADUATE ASSISTANT Policy Information & Directions for GA Termination 1. Once appointed, graduate assistants may not have their tuition/fees revoked standards, the Termination of Graduate Assistant form may be used to terminate a GA appointment

  20. Advanced wellbore thermal simulator GEOTEMP2 research report

    SciTech Connect (OSTI)

    Mitchell, R.F.

    1982-02-01T23:59:59.000Z

    The development of the GEOTEMP2 wellbore thermal simulator is described. The major technical features include a general purpose air and mist drilling simulator and a two-phase steam flow simulator that can model either injection or production.

  1. Reservoir management using streamline simulation

    E-Print Network [OSTI]

    Choudhary, Manoj Kumar

    2000-01-01T23:59:59.000Z

    of information and sparsity of data. Quantifying this uncertainty in terms of reservoir performance forecast poses a major reservoir management challenge. One solution to this problem is flow simulation of a large number of these plausible reservoir descriptions...

  2. Profiles in Leadership: Christopher Smith, Assistant Secretary...

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

    Profiles in Leadership: Christopher Smith, Assistant Secretary for Fossil Energy Profiles in Leadership: Christopher Smith, Assistant Secretary for Fossil Energy July 15, 2015 -...

  3. Federal Energy Management Program (FEMP) Technical Assistance...

    Energy Savers [EERE]

    Federal Energy Management Program (FEMP) Technical Assistance Request Portal User Guide Federal Energy Management Program (FEMP) Technical Assistance Request Portal User Guide...

  4. Electrically-Assisted Diesel Particulate Filter Regeneration...

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

    Evaluation pm041lance2011p.pdf More Documents & Publications Electrically-Assisted Diesel Particulate Filter Regeneration Substrate Studies of an Electrically-Assisted Diesel...

  5. Rural Enterprise Assistance Project's Loan Program (Nebraska)

    Broader source: Energy.gov [DOE]

    The Rural Enterprise Assistance Project (REAP) offers four services: financing (micro loans), business training, technical assistance, and networking. REAP's Loan Program focuses on providing...

  6. Energy Department Technical Assistance Bolsters Tribal Clean...

    Energy Savers [EERE]

    Technical Assistance Bolsters Tribal Clean Energy Deployment Energy Department Technical Assistance Bolsters Tribal Clean Energy Deployment December 2, 2011 - 3:39pm Addthis The...

  7. ARRA Proposed Award: Energy Technology Assistance Program

    E-Print Network [OSTI]

    ARRA Proposed Award: Energy Technology Assistance Program Statewide Program ­ covering Greater. Highlights: Energy Technology Assistance Program (ETAP) is a statewide program that will focus on providing

  8. Computational Methods for Design-Assisted Mask Flows

    E-Print Network [OSTI]

    Kagalwalla, Abde Ali Hunaid

    2014-01-01T23:59:59.000Z

    polygon/doc/index.html. [boob] “Boost Polygon Library. ”using Boost Polygon Library [boob]. Fourier transform of the

  9. Flow chamber

    DOE Patents [OSTI]

    Morozov, Victor (Manassas, VA)

    2011-01-18T23:59:59.000Z

    A flow chamber having a vacuum chamber and a specimen chamber. The specimen chamber may have an opening through which a fluid may be introduced and an opening through which the fluid may exit. The vacuum chamber may have an opening through which contents of the vacuum chamber may be evacuated. A portion of the flow chamber may be flexible, and a vacuum may be used to hold the components of the flow chamber together.

  10. Flow Split Venturi, Axially-Rotated Valve

    DOE Patents [OSTI]

    Walrath, David E. (Laramie, WY); Lindberg, William R. (Laramie, WY); Burgess, Robert K. (Sheridan, WY); LaBelle, James (Murrieta, CA)

    2000-02-22T23:59:59.000Z

    The present invention provides an axially-rotated valve which permits increased flow rates and lower pressure drop (characterized by a lower loss coefficient) by using an axial eccentric split venturi with two portions where at least one portion is rotatable with respect to the other portion. The axially-rotated valve typically may be designed to avoid flow separation and/or cavitation at full flow under a variety of conditions. Similarly, the valve is designed, in some embodiments, to produce streamlined flow within the valve. An axially aligned outlet may also increase the flow efficiency. A typical cross section of the eccentric split venturi may be non-axisymmetric such as a semicircular cross section which may assist in both throttling capabilities and in maximum flow capacity using the design of the present invention. Such a design can include applications for freeze resistant axially-rotated valves and may be fully-opened and fully-closed in one-half of a complete rotation. An internal wide radius elbow typically connected to a rotatable portion of the eccentric venturi may assist in directing flow with lower friction losses. A valve actuator may actuate in an axial manner yet be uniquely located outside of the axial flow path to further reduce friction losses. A seal may be used between the two portions that may include a peripheral and diametrical seal in the same plane. A seal separator may increase the useful life of the seal between the fixed and rotatable portions.

  11. Geological flows

    E-Print Network [OSTI]

    Yu. N. Bratkov

    2008-11-19T23:59:59.000Z

    In this paper geology and planetology are considered using new conceptual basis of high-speed flow dynamics. Recent photo technics allow to see all details of a flow, 'cause the flow is static during very short time interval. On the other hand, maps and images of many planets are accessible. Identity of geological flows and high-speed gas dynamics is demonstrated. There is another time scale, and no more. All results, as far as the concept, are new and belong to the author. No formulae, pictures only.

  12. Nodes, modes and flow codes

    SciTech Connect (OSTI)

    Karniadakis, G.E.; Orszag, S.A. (Princeton Univ., NJ (United States))

    1993-03-01T23:59:59.000Z

    Computational fluid dynamics and the numerical prediction of fluid flow in the understanding and modeling of turbulence is discussed with emphasis on the development of direct numerical simulation (DNS) of high-Reynolds number turbulent flows. Recent advances in computer systems and their use in turbulence simulation are reviewed and the need for parallel processing to achieve teraflop speeds necessary for DNS is discussed. Computer system architectures, nodes, and parallel computers currently in use are reviewed. Spectral, spectral-element, particle, and hybrid difference methods of solving incompressible- and compressible-flow problems are examined. Four applications of parallel computers to turbulent flow problems are presented and future developments in computer systems are discussed. 24 refs.

  13. Lagrangian Simulation of Combustion

    SciTech Connect (OSTI)

    Ahmed F. Ghoniem

    2008-05-01T23:59:59.000Z

    A Lagrangian approach for the simulation of reactive flows has been developed during the course of this project, and has been applied to a number of significant and challenging problems including the transverse jet simulations. An efficient strategy for parallel domain decomposition has also been developed to enable the implementation of the approach on massively parallel architecture. Since 2005, we focused our efforts on the development of a semi-Lagrangian treatment of diffusion, and fast and accurate Lagrangian simulation tools for multiphysics problems including combustion.

  14. Assistant Professor Cropping Systems Specialist

    E-Print Network [OSTI]

    Veiga, Pedro Manuel Barbosa

    Assistant Professor Cropping Systems Specialist Department of Plant and Soil Sciences POSITION DESCRIPTION The Department of Plant and Soil Sciences, Oklahoma State University is seeking, implementing, and evaluating educational programs to meet the needs of producers for improving existing

  15. Assistant Professor Agricultural Systems Modeler

    E-Print Network [OSTI]

    Veiga, Pedro Manuel Barbosa

    Assistant Professor Agricultural Systems Modeler Department of Plant and Soil Sciences Division of Agricultural Sciences and Natural Resources Oklahoma State University ­ Stillwater, Oklahoma POSITION DESCRIPTION The Department of Plant and Soil Sciences, Oklahoma State University is seeking applicants

  16. Engineering Organization Chart Assistant Dean

    E-Print Network [OSTI]

    Delene, David J.

    Engineering Organization Chart Fall `12 Assistant Dean Outreach & Recruiting Matthew Cavalli and Geological Engineering Joseph Hartman Chair, Petroleum Engineering Steve Benson Chair, Electrical Engineering Forrest Ames (interim) Chair, Mechanical Engineering Matthew Cavalli Chair, Chemical Engineering Mike Mann

  17. Simulation of geothermal subsidence

    SciTech Connect (OSTI)

    Miller, I.; Dershowitz, W.; Jones, K.; Myer, L.; Roman, K.; Schauer, M.

    1980-03-01T23:59:59.000Z

    The results of an assessment of existing mathematical models for subsidence simulation and prediction are summarized. The following subjects are discussed: the prediction process, physical processes of geothermal subsidence, computational models for reservoir flow, computational models for deformation, proficiency assessment, and real and idealized case studies. (MHR)

  18. Characterizing Flow in Oil Reservoir Rock Using Smooth Particle Hydrodynamics

    E-Print Network [OSTI]

    Holmes, David W.

    In this paper, a 3D Smooth Particle Hydrodynamics (SPH) simulator for modeling grain scale fluid flow in porous rock is presented. The versatility of the SPH method has driven its use in increasingly complex areas of flow ...

  19. Feedback control of flow separation using synthetic jets

    E-Print Network [OSTI]

    Kim, Kihwan

    2006-04-12T23:59:59.000Z

    The primary goal of this research is to assess the effect of synthetic jets on flow separation and provide a feedback control strategy for flow separation using synthetic jets. The feedback control synthesis is conducted based upon CFD simulation...

  20. A numerical study of flow-structure interactions with application to flow past a pair of cylinders

    E-Print Network [OSTI]

    Papaioannou, Georgios (Georgios Vasilios), 1975-

    2004-01-01T23:59:59.000Z

    Flow-structure interaction is a generic problem for many engineering applications, such as flow--induced oscillations of marine risers and cables. In this thesis a Direct Numerical Simulation (DNS) approach based on ...

  1. A study of surfactant-assisted waterflooding

    SciTech Connect (OSTI)

    Scamehorn, J.F.; Harwell, J.H.

    1990-09-01T23:59:59.000Z

    In surfactant-assisted waterflooding, a surfactant slug is injected into a reservoir, followed by a brine spacer, followed by second surfactant slug. The charge on the surfactant in the first slug has opposite sign to that in the second slug. When the two slugs mix in the reservoir, a precipitate or coacervate is formed which plugs the permeable region of the reservoir. Subsequently injected water or brine is forced through the low permeability region of the reservoir, increasing sweep efficiency of the waterflood, compared to a waterflood not using surfactants. In this part of the work, two major tasks are performed. First, core floods are performed with oil present to demonstrate the improvement in incremental oil production, as well as permeability modification. Second, a reservoir simulation model will be proposed to further delineate the optimum strategy for implementation of the surfactant-assisted waterflooding, as well as indicate the reservoir types for which it would be most effective. Surfactants utilized were sodium dodecyl sulfate and dodecyl pyridinium chloride. 44 refs., 17 figs., 3 tabs.

  2. Environmentally assisted cracking in light water reactors

    SciTech Connect (OSTI)

    Chopra, O.K.; Chung, H.M.; Gruber, E.E. [and others

    1996-07-01T23:59:59.000Z

    This report summarizes work performed by Argonne National Laboratory on fatigue and environmentally assisted cracking (EAC) in light water reactors (LWRs) from April 1995 to December 1995. Topics that have been investigated include fatigue of carbon and low-alloy steel used in reactor piping and pressure vessels, EAC of Alloy 600 and 690, and irradiation-assisted stress corrosion cracking (IASCC) of Type 304 SS. Fatigue tests were conducted on ferritic steels in water that contained various concentrations of dissolved oxygen (DO) to determine whether a slow strain rate applied during different portions of a tensile-loading cycle are equally effective in decreasing fatigue life. Crack-growth-rate tests were conducted on compact-tension specimens from several heats of Alloys 600 and 690 in simulated LWR environments. Effects of fluoride-ion contamination on susceptibility to intergranular cracking of high- and commercial- purity Type 304 SS specimens from control-tensile tests at 288 degrees Centigrade. Microchemical changes in the specimens were studied by Auger electron spectroscopy and scanning electron microscopy to determine whether trace impurity elements may contribute to IASCC of these materials.

  3. Stress-Assisted Corrosion in Boiler Tubes

    SciTech Connect (OSTI)

    Preet M Singh; Steven J Pawel

    2006-05-27T23:59:59.000Z

    A number of industrial boilers, including in the pulp and paper industry, needed to replace their lower furnace tubes or decommission many recovery boilers due to stress-assisted corrosion (SAC) on the waterside of boiler tubes. More than half of the power and recovery boilers that have been inspected reveal SAC damage, which portends significant energy and economic impacts. The goal of this project was to clarify the mechanism of stress-assisted corrosion (SAC) of boiler tubes for the purpose of determining key parameters in its mitigation and control. To accomplish this in-situ strain measurements on boiler tubes were made. Boiler water environment was simulated in the laboratory and effects of water chemistry on SAC initiation and growth were evaluated in terms of industrial operations. Results from this project have shown that the dissolved oxygen is single most important factor in SAC initiation on carbon steel samples. Control of dissolved oxygen can be used to mitigate SAC in industrial boilers. Results have also shown that sharp corrosion fatigue and bulbous SAC cracks have similar mechanism but the morphology is different due to availability of oxygen during boiler shutdown conditions. Results are described in the final technical report.

  4. Up-Scaling Geochemical Reaction Rates Accompanying Acidic CO2-Saturated Brine Flow in Sandstone Aquifers

    E-Print Network [OSTI]

    New York at Stoney Brook, State University of

    1 Up-Scaling Geochemical Reaction Rates Accompanying Acidic CO2-Saturated Brine Flow in Sandstone models. As a step toward this, network flow models were used to simulate the flow of CO2-saturated brine

  5. Some questions regarding the understanding and prediction of turbulent flow

    E-Print Network [OSTI]

    Heinz, Stefan

    more com- petitive industrial processes involving fluid flows. Internal combustion engine, energy predictions: the computational costs of such direct numerical simulation (DNS) do not allow applications

  6. The MIT Design Advisor : simple and rapid energy simulation of early-stage building designs

    E-Print Network [OSTI]

    Urban, Bryan J. (Bryan James)

    2007-01-01T23:59:59.000Z

    Simulation tools, when applied early in the design process, can considerably reduce the energy demand of newly constructed buildings. For a simulation tool to assist with design, it must be easy to use, provide feedback ...

  7. Numerical Simulation of Condensation in Transonic Flows

    E-Print Network [OSTI]

    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

  8. NUMERICAL SIMULATION OF INCOMPRESSIBLE FLOWS IN ...

    E-Print Network [OSTI]

    PDEs by boundary layer or quasi-geostrophic approximations, as well as imposing ... are to be completed with admissible initial and boundary conditions. ... eral practice, especially for spectral approximations, to treat the nonlinear terms .... spectral-Galerkin method in [19] is as good, if not more efficient and accurate, as.

  9. Adiabatic thermal Child-Langmuir flow

    E-Print Network [OSTI]

    Mok, Rachel V. (Rachel Verla)

    2013-01-01T23:59:59.000Z

    A simulation model is presented for the verification of the recently developed steady-state one-dimensional adiabatic thermal Child-Langmuir flow theory. In this theory, a self-consistent Poisson equation is developed ...

  10. Dynamics of Polymers in Flowing Colloidal Suspensions

    E-Print Network [OSTI]

    Chen, Hsieh

    Using hydrodynamic simulations we examine the behavior of single polymers in a confined colloidal suspension under flow. We study the conformations of both, collapsed and noncollapsed polymers. Our results show that the ...

  11. A survey of air flow models for multizone structures

    SciTech Connect (OSTI)

    Feustel, H.E.; Dieris, J.

    1991-03-01T23:59:59.000Z

    Air flow models are used to simulate the rates of incoming and outgoing air flows for a building with known leakage under given weather and shielding conditions. Additional information about the flow paths and air-mass flows inside the building can only by using multizone air flow models. In order to obtain more information on multizone air flow models, a literature review was performed in 1984. A second literature review and a questionnaire survey performed in 1989, revealed the existence of 50 multizone air flow models, all developed since 1966, two of which are still under development. All these programs use similar flow equations for crack flow but differ in the versatility to describe the full range of flow phenomena and the algorithm provided for solving the set of nonlinear equations. This literature review was found that newer models are able to describe and simulate the ventilation systems and interrelation of mechanical and natural ventilation. 27 refs., 2 figs., 1 tab.

  12. Modeling of Organizational Violence Violent Intent Modeling and Simulation (VIMS)

    E-Print Network [OSTI]

    McShea, Daniel W.

    111 Modeling of Organizational Violence Violent Intent Modeling and Simulation (VIMS) Georgiy and organizational violence ­ Use social science theories to assist analysis in understanding potential scenarios 2 Organizational Behavior (MAROB) · Global Terrorism Database (GTD) · The Big Allied And Dangerous (BAAD

  13. LANL, Sandia celebrate success at New Mexico Small Business Assistance...

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

    success at NM Small Business Assistance fest LANL, Sandia celebrate success at New Mexico Small Business Assistance fest The New Mexico Small Business Assistance (NMSBA)...

  14. START Program for Renewable Energy Project Development Assistance...

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

    Program for Renewable Energy Project Development Assistance START Program for Renewable Energy Project Development Assistance The Strategic Technical Assistance Response Team...

  15. assistance program personnel: Topics by E-print Network

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

    Medical Escort Services ** Repatriation of Remains ** Replacement of Medication or Eyeglasses EmergencyOverview of Emergency Travel Assistance TRAVEL ASSISTANCE The Team Assist...

  16. assistants essential tools: Topics by E-print Network

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

    Medical Escort Services ** Repatriation of Remains ** Replacement of Medication or Eyeglasses EmergencyOverview of Emergency Travel Assistance TRAVEL ASSISTANCE The Team Assist...

  17. State and Regional Policy Assistance - Program Activities | Department...

    Office of Environmental Management (EM)

    Technical assistance provided to WGAWIEB by the Electricity Market Studies Group of LBNL and The Regulatory Assistance Project (RAP); and More limited technical assistance...

  18. PERFORMANCE OF FULLY-COUPLED DOMAIN DECOMPOSITION PRECONDITIONERS for FINITE ELEMENT TRANSPORT / REACTION SIMULATIONS1

    E-Print Network [OSTI]

    Tuminaro, Ray S.

    element simulation of strongly coupled fluid flow, heat transfer, and mass transfer with non methods, stabilized finite element methods. 1. INTRODUCTION Modern computational fluid dynamics flows with unstructured mesh finite element methods. These flow problems are characterized by both

  19. Assistant Director, Prospect Management Description

    E-Print Network [OSTI]

    Portman, Douglas

    and to the Prospect Management Data Wranglers to assist their efforts in improving the quality of Prospect Management Management · Enter and monitor prospect assignments and new prospect records requests. · Monitor data quality of all functions and systems related to prospect management, including software applications, industry

  20. New Mexico Small Business Assistance

    E-Print Network [OSTI]

    New Mexico Small Business Assistance Program (NMSBA) helps small businesses in New Mexico access counties solve their technical challenges through NMSBA. Economic Impact of the Small Businesses related to NMSBA Small Business Jobs Created/Retained 2,874 Average Salary $38,647 Increased Revenue $145.2M

  1. Laura M. Grabowski Assistant Professor

    E-Print Network [OSTI]

    Grabowski, Laura M. - Department of Computer Science, University of Texas

    " Advisor: Dr. Richard Fowler MASTER OF ARTS May 1983 Communications/Theatre Bowling Green State University Committee Chair BACHELOR OF ARTS June 1980 Major: French; Minor: Dance Bowling Green State University Department of Theatre Bowling Green State University, Bowling Green, Ohio Graduate Teaching Assistant August

  2. The Effect of High Rotational Speed on the Performance of Straight-through Labyrinth Seals for Compressible and Incompressible Flow

    E-Print Network [OSTI]

    Obidigbo, Ekene R.

    2012-07-16T23:59:59.000Z

    The leakage flow through straight through labyrinth seals with tooth on stator was investigated by performing CFD simulations .ANSYS Fluent is used to simulate the fluid flow through straight through Labyrinth seals. The effect of seal geometry...

  3. Energy Technical Assistance: Industrial Processes Program

    E-Print Network [OSTI]

    McClure, J. D.

    1980-01-01T23:59:59.000Z

    The Energy Technical Assistance Division of Texas Engineering Extension Service (TEEX) has implemented an energy conservation program to assist small industry in using energy more efficiently. This full time service, an outgrowth of the Texas A...

  4. START Renewable Energy Project Development Assistance | Department...

    Energy Savers [EERE]

    START Renewable Energy Project Development Assistance START Renewable Energy Project Development Assistance May 1, 2015 11:59PM EDT U.S. Department of Energy The U.S. Department of...

  5. Obtaining Disaster Assistance for Public Infrastructure

    E-Print Network [OSTI]

    Taylor, Greg

    2005-10-10T23:59:59.000Z

    County and municipal governments, as well as certain private non-profit organizations, may qualify for assistance in rebuilding public infrastructure after a natural disaster. This leaflet details the assistance programs available from the Federal...

  6. Assistant Secretary Hoffman Discusses Grid Modernization with...

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

    Assistant Secretary Hoffman Discusses Grid Modernization with the New York Times and E&E TV Assistant Secretary Hoffman Discusses Grid Modernization with the New York Times and E&E...

  7. Job Position Description Job Title: Office Assistant

    E-Print Network [OSTI]

    Moore, Paul A.

    Job Position Description Job Title: Office Assistant A. Main purpose of the job: To assist of Campus Operations. B. Primary responsibilities or key duties of the job (tasks performed regularly

  8. Job Position Description Job Title: Locksmith Assistant

    E-Print Network [OSTI]

    Moore, Paul A.

    Job Position Description Job Title: Locksmith Assistant A. Main purpose of the job: Assist responsibilities or key duties of the job (tasks performed regularly): 1. Perform lock changes in all facilities

  9. Energy Technical Assistance: Industrial Processes Program 

    E-Print Network [OSTI]

    McClure, J. D.

    1980-01-01T23:59:59.000Z

    The Energy Technical Assistance Division of Texas Engineering Extension Service (TEEX) has implemented an energy conservation program to assist small industry in using energy more efficiently. This full time service, an outgrowth of the Texas A...

  10. SimHydro 2014:Modelling of rapid transitory flows,11-13 June 2014, Sophia Antipolis Marechal E., Khelladi S., Ravelet F., Delepierre-Massue O,. Bakir F Towards numerical simulation of snow showersin jet-engine fuel systems.

    E-Print Network [OSTI]

    Boyer, Edmond

    uncontrollably if icing occurs on the horizontal or vertical stabilizer. Obstruction of pitot tube will causeSimHydro 2014:Modelling of rapid transitory flows,11-13 June 2014, Sophia Antipolis ­Marechal E at low temperatures. If the flow rate is increased, sudden releases of large quantities of ice may occur

  11. (Preview Draft) Chapter 4. Accumulating the Flows

    E-Print Network [OSTI]

    Ford, Andrew

    't take long because you only needed to update the stock very dec as a combination of stocks and flows and then simulated on the computer. The simulation results are generated adopted for this example. CO2 in the atmosphere is a stock measured in Gigatons of Carbon, abbreviated GTC

  12. Radiological Assistance Program | National Nuclear Security Administra...

    National Nuclear Security Administration (NNSA)

    Federal Radiological Monitoring and Assessment Center Emergency Response Accident Response Group Radiation Emergency Assistance Center Training Site National Atmospheric Release...

  13. DFSP - a data flow signal processor

    SciTech Connect (OSTI)

    Hartimo, I.; Simula, O.; Skytta, J.; Kronlof, K.

    1986-01-01T23:59:59.000Z

    The concept of data flow computing is applied to digital signal processing (DSP). A data flow signal processor (DFSP) architecture is presented. The principles of data flow computing are carefully considered in order to conform with the special properties of DSP. The bus oriented architecture is easily configured to meet various performance requirements. The DFSP architecture is most suitable for nonrecursive algorithms. Typical tasks of this nature are transforms and FIR filters. A simulation model of the DFSP architecture has been developed. Simulation results of two application examples are given. 24 references.

  14. Graduate Assistant Stipend Enhancement Project Proposal Type

    E-Print Network [OSTI]

    Karonis, Nicholas T.

    1 Graduate Assistant Stipend Enhancement Project Proposal Type The Graduate Assistant Stipend Strategic Plan. Goals The Graduate Assistant Stipend Enhancement project consists of two programs: the Great. Fundamentally, the project seeks to increase the number of graduate students who receive assistantships

  15. START Renewable Energy Project Development Assistance

    Broader source: Energy.gov [DOE]

    The DOE Office of Indian Energy is now accepting applications for the third round of the Strategic Technical Assistance Response Team (START) Renewable Energy Project Development Assistance Program to provide Tribes with technical assistance with furthering the development of community- and commercial-scale renewable energy projects. Applications are due May 1, 2015, and up to five projects will be selected in June 2015.

  16. WARREN RESIDENTIAL LIFE RESIDENT ASSISTANT POSITION DESCRIPTION

    E-Print Network [OSTI]

    Russell, Lynn

    WARREN RESIDENTIAL LIFE RESIDENT ASSISTANT POSITION DESCRIPTION The position of Resident Assistant for students living within the Warren College residential community. Resident Assistant's (RA's) are principle members of the Warren Residential Life staff. In accordance with the University of California's Personnel

  17. Modeling-Computer Simulations At Long Valley Caldera Geothermal...

    Open Energy Info (EERE)

    Modeling-Computer Simulations Activity Date - 2003 Usefulness not indicated DOE-funding Unknown Notes Several fluid-flow models presented regarding the Long Valley Caldera....

  18. Electrically-Assisted Turbocharger Development for Performance and Emissions

    SciTech Connect (OSTI)

    Bailey, Milton

    2000-08-20T23:59:59.000Z

    Turbocharger transient lag inherently imposes a tradeoff between a robust engine response to transient load shifts and exhaust emissions. By itself, a well matched turbocharger for an engine has limited flexibility in improving this transient response. Electrically-assisted turbocharging has been seen as an attractive option to improve response and lower transient emissions. This paper presents the results of a multi-year joint CRADA between DDC and ORNL. Virtual lab diesel simulation models characterized the performance improvement potential of an electrically assisted turbocharger technology. Operating requirements to reduce transient duration between load shift time by up to 50% were determined. A turbomachine has been conceptualized with an integrated motor-generator, providing transient burst boost plus energy recovery capability. Numerous electric motor designs were considered, and a prototype motor was developed, fabricated, and is undergoing tests. Power controls have been designed and fabricated.

  19. Loop simulation capability for sodium-cooled systems

    E-Print Network [OSTI]

    Adekugbe, Oluwole A.

    1984-01-01T23:59:59.000Z

    A one-dimensional loop simulation capability has been implemented in the thermal-hydraulic analysis code, THERMIT-4E. This code had been used to simulate and investigate flow in test sections of experimental sodium loops ...

  20. (Preview Draft) Chapter 5. Water Flows in the Mono Basin

    E-Print Network [OSTI]

    Ford, Andrew

    of people began a campaign to save a dying lake, taking on not only the City of Los Angeles, but the entire a modeling point of view, Mono Lake is well suited to demonstrate the power of stock and flow modeling. We will be simulating the flows and accumulation of water, so the stock and flow concepts will be easy to understand

  1. assisted reproductive technology: Topics by E-print Network

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

    consumer information. Referral Date: Consumer's Name: Date of Birth Assistive Technology Assessment Computer Skills Assessment Assistive TechnologyComputer...

  2. assisted reproduction technology: Topics by E-print Network

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

    consumer information. Referral Date: Consumer's Name: Date of Birth Assistive Technology Assessment Computer Skills Assessment Assistive TechnologyComputer...

  3. assisted reproduction technologies: Topics by E-print Network

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

    consumer information. Referral Date: Consumer's Name: Date of Birth Assistive Technology Assessment Computer Skills Assessment Assistive TechnologyComputer...

  4. Office of the Assistant General Counsel for Procurement and Financial...

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

    and Financial Assistance Regulations: Federal Acquisition Regulation Department of Energy Acquisition Regulation Department of Energy Financial Assistance Regulations Office...

  5. Magnetic Amplifier for Power Flow Control

    SciTech Connect (OSTI)

    None

    2012-02-24T23:59:59.000Z

    GENI Project: ORNL is developing an electromagnet-based, amplifier-like device that will allow for complete control over the flow of power within the electric grid. To date, complete control of power flow within the grid has been prohibitively expensive. ORNL’s controller could provide a reliable, cost-effective solution to this problem. The team is combining two types of pre-existing technologies to assist in flow control, culminating in a prototype iron-based magnetic amplifier. Ordinarily, such a device would require expensive superconductive wire, but the magnetic iron core of ORNL’s device could serve as a low-cost alternative that is equally adept at regulating power flow.

  6. Parallel-Flow-Shear Driven Low-Frequency Plasma Instability

    SciTech Connect (OSTI)

    Ishiguro, Seiji [Theory and Computer Simulation Center, National Institute for Fusion Science, Toki-shi, Gifu 509-5292 (Japan); Matsumoto, Noriaki; Kaneko, Toshiro; Hatakeyama, Rikizo [Department of Electronic Engineering, Tohoku University, Sendai 980-8579 (Japan)

    2004-12-01T23:59:59.000Z

    Full three dimensional Particle-in-Cell (PIC) simulations are performed in order to investigate effects of field-aligned (parallel) ion flow shears on low-frequency plasma instabilities. It is shown that the parallel ion flow velocity shear can induce the ion-acoustic instability, even when the ion flow velocity is so small that the instability can not take place. Simulation results are consistent with the analysis based on the local theory.

  7. Computer Assisted Parallel Program Generation

    E-Print Network [OSTI]

    Kawata, Shigeo

    2015-01-01T23:59:59.000Z

    Parallel computation is widely employed in scientific researches, engineering activities and product development. Parallel program writing itself is not always a simple task depending on problems solved. Large-scale scientific computing, huge data analyses and precise visualizations, for example, would require parallel computations, and the parallel computing needs the parallelization techniques. In this Chapter a parallel program generation support is discussed, and a computer-assisted parallel program generation system P-NCAS is introduced. Computer assisted problem solving is one of key methods to promote innovations in science and engineering, and contributes to enrich our society and our life toward a programming-free environment in computing science. Problem solving environments (PSE) research activities had started to enhance the programming power in 1970's. The P-NCAS is one of the PSEs; The PSE concept provides an integrated human-friendly computational software and hardware system to solve a target ...

  8. Zonal flow dynamics in the double tearing mode with antisymmetric shear flows

    SciTech Connect (OSTI)

    Mao, Aohua [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China) [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Graduate School of Energy Science, Kyoto University, Uji, Kyoto 6110011 (Japan); Li, Jiquan, E-mail: lijq@energy.kyoto-u.ac.jp [Graduate School of Energy Science, Kyoto University, Uji, Kyoto 6110011 (Japan)] [Graduate School of Energy Science, Kyoto University, Uji, Kyoto 6110011 (Japan); Liu, Jinyuan, E-mail: jyliu@dlut.edu.cn [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)] [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Kishimoto, Yasuaki [Graduate School of Energy Science, Kyoto University, Uji, Kyoto 6110011 (Japan) [Graduate School of Energy Science, Kyoto University, Uji, Kyoto 6110011 (Japan); Institude of Advanced Energy, Kyoto University, Uji, Kyoto 6110011 (Japan)

    2014-05-15T23:59:59.000Z

    The generation dynamics and the structural characteristics of zonal flows are investigated in the double tearing mode (DTM) with antisymmetric shear flows. Two kinds of zonal flow oscillations are revealed based on reduced resistive magnetohydrodynamics simulations, which depend on the shear flow amplitudes corresponding to different DTM eigen mode states, elaborated by Mao et al. [Phys. Plasmas 20, 022114 (2013)]. For the weak shear flows below an amplitude threshold, v{sub c}, at which two DTM eigen states with antisymmetric or symmetric magnetic island structure are degenerated, the zonal flows grow oscillatorily in the Rutherford regime during the nonlinear evolution of the DTMs. It is identified that the oscillation mechanism results from the nonlinear interaction between the distorted islands and the zonal flows through the modification of shear flows. However, for the medium shear flows above v{sub c} but below the critical threshold of the Kelvin-Helmholtz instability, an oscillatory growing zonal flow occurs in the linear phase of the DTM evolution. It is demonstrated that the zonal flow oscillation originates from the three-wave mode coupling or a modulation instability pumped by two DTM eigen modes with the same frequency but opposite propagating direction. With the shear flows increasing, the amplitude of zonal flow oscillation increases first and then decreases, whilst the oscillation frequency as twice of the Doppler frequency shift increases. Furthermore, impacts of the oscillatory zonal flows on the nonlinear evolution of DTM islands and the global reconnection are also discussed briefly.

  9. Assistive Devices for the Home

    E-Print Network [OSTI]

    Harris, Janie

    2002-01-31T23:59:59.000Z

    , contact a physical therapist or occupational therapist through a home health agency or your local hospital. The following Web sites have information about devices that can make your home safer and more functional: http...Assistive Devices for the Home Janie Harris Extension Specialist, Housing and Environment The Texas A&M University System If you were to become impaired or disabled from an accident or illness, how ?user-friendly? would your home be? There are many...

  10. Computer Assisted Virtual Environment - CAVE

    ScienceCinema (OSTI)

    Erickson, Phillip; Podgorney, Robert; Weingartner, Shawn; Whiting, Eric

    2014-06-09T23:59:59.000Z

    Research at the Center for Advanced Energy Studies is taking on another dimension with a 3-D device known as a Computer Assisted Virtual Environment. The CAVE uses projection to display high-end computer graphics on three walls and the floor. By wearing 3-D glasses to create depth perception and holding a wand to move and rotate images, users can delve into data.

  11. A general-purpose, geochemical reservoir simulator

    SciTech Connect (OSTI)

    Liu, X.; Ortoleva, P.

    1996-12-31T23:59:59.000Z

    A geochemical simulator for the analysis of coupled reaction and transport processes is presented. The simulator is based on the numerical solution of the equations of coupled multi-phase fluid flow, species transport, energy balance and rock/fluid reactions. It also accounts for the effects of grain growth/dissolution and the alteration of porosity and permeability due to mineral reactions. The simulator can be used to analyze core floods, single-well scenarios and multiple production/injection well systems on the reservoir scale. Additionally, the simulator provides two flow options: the Darcy law for fluid flow in porous media and the Brinkman law that subsumes both free and porous medium flows. The simulator was tested using core acidizing data and results were in good agreement with laboratory observations. The simulator was applied to analyze matrix acidizing treatments for a horizontal well. The evolution of the skin factor was predicted and the optimal volume of acid required to remove the near-wellbore damage was determined. Reactive fluid infiltration was shown to lead to reaction-front fingering under certain conditions. Viscosity contrast in multiphase flow could also result in viscous fingering. Examples in this study also address these nonlinear fingering phenomena. A waterflood on the reservoir scale was analyzed and simulation results show that scale formation during waterfloods can occur far beyond injection wells. Two cases of waste disposal by deep well injection were evaluated and our simulation results were consistent with field measured data.

  12. Transportation Analysis, Modeling, and Simulation (TAMS) Application

    E-Print Network [OSTI]

    Transportation Analysis, Modeling, and Simulation (TAMS) Application Center for Transportation Passenger Flows Supply Chain Efficiency Transportation: Energy Environment Safety Security Vehicle Technologies T he Center for Transportation Analysis (CTA) TAMS application is a web-based tool that supports

  13. Groundwater Recharge Simulator M. Tech. Thesis

    E-Print Network [OSTI]

    Sohoni, Milind

    Groundwater Recharge Simulator M. Tech. Thesis by Dharmvir Kumar Roll No: 07305902 Guide: Prof;Contents 1 Introduction 1 1.1 Groundwater Theory.1.5 Groundwater Flow Equation . . . . . . . . . . . . . . . . . . . . . . 11 1.2 Numerical Solvers and Boundary

  14. Improvement of semiconductor optical amplifier dynamic behaviour by assist light injection

    E-Print Network [OSTI]

    Haddadi, Hamed

    be used to model carrier dynamics. Simulations and experimental results in presence of the assist lightB) 3-6 Polarization sensitive Electrical -3dB gain bandwidth (nm) 30-70 Saturation). A propagation equation can be used to characterize the evolution of the electrical field and rate equations can

  15. Cost-Effective Multi-Mode Offloading with peer-assisted communications

    E-Print Network [OSTI]

    Gorinsky, Sergey

    cost in terms of financial settlement, energy consump- tion, and user satisfaction. Our simulationsCost-Effective Multi-Mode Offloading with peer-assisted communications Ioannis Komnios a, , Fani caused by the ongoing explosive growth in mobile data traffic. In this paper, we propose Cost

  16. Assistance

    Broader source: Energy.gov [DOE]

    The Department of Energy (DOE) assurance systems are designed to meet the needs and unique risks of each DOE site or activity, include methods to perform rigorous self-assessments, conduct feedback...

  17. Jet quenching and elliptic flow

    E-Print Network [OSTI]

    A. K. Chaudhuri

    2007-08-29T23:59:59.000Z

    In jet quenching, a hard QCD parton, before fragmenting into a jet of hadrons, deposits a fraction of its energy in the medium, leading to suppressed production of high-$p_T$ hadrons. Assuming that the deposited energy quickly thermalizes, we simulate the subsequent hydrodynamic evolution of the QGP fluid. Explicit simulation of Au+Au collision with and without a quenching jet indicate that elliptic flow is greatly reduced in a jet event. The result can be used to identify the jet events in heavy ion collisions.

  18. Gradual Variation Analysis for Groundwater Flow

    E-Print Network [OSTI]

    Chen, Li

    2010-01-01T23:59:59.000Z

    Groundwater flow in Washington DC greatly influences the surface water quality in urban areas. The current methods of flow estimation, based on Darcy's Law and the groundwater flow equation, can be described by the diffusion equation (the transient flow) and the Laplace equation (the steady-state flow). The Laplace equation is a simplification of the diffusion equation under the condition that the aquifer has a recharging boundary. The practical way of calculation is to use numerical methods to solve these equations. The most popular system is called MODFLOW, which was developed by USGS. MODFLOW is based on the finite-difference method in rectangular Cartesian coordinates. MODFLOW can be viewed as a "quasi 3D" simulation since it only deals with the vertical average (no z-direction derivative). Flow calculations between the 2D horizontal layers use the concept of leakage. In this project, we have established a mathematical model based on gradually varied functions for groundwater data volume reconstruction. T...

  19. Get Assistance | Department of Energy

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

    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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33Frequently20,000 RussianBy: Thomas P. D'Agostino, Undersecretary11-161-LNGGaryTechnical assistance

  20. Financial Assistance | Department of Energy

    Energy Savers [EERE]

    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 onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directed off Energy.gov. Are you sure you want toworldPowerHome |CookingFAQsFacilityFederalAssistance

  1. Technical Assistance | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onYouTube YouTube Note: Since the.pdfBreakingMayDepartment ofEnergyTeam Cumberland » TeamTechnical Assistance

  2. Technical Assistance: Increasing Code Compliance

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

    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 DataDepartment of Energy Your Density Isn'tOriginEducationVideoStrategic| Department ofGeneralWind »Assistance: Increasing Code Compliance

  3. Technology Assistance Program | Partnerships | ORNL

    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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our InstagramStructureProposedPAGESafety Tag:8,, 20153Assistance Program SHARE

  4. A Guide for Using the Transient Ground-Water Flow Model of the Death Valley Regional Ground-Water Flow System, Nevada and California

    SciTech Connect (OSTI)

    Joan B. Blainey; Claudia C. Faunt, and Mary C. Hill

    2006-05-16T23:59:59.000Z

    This report is a guide for executing numerical simulations with the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California using the U.S. Geological Survey modular finite-difference ground-water flow model, MODFLOW-2000. Model inputs, including observations of hydraulic head, discharge, and boundary flows, are summarized. Modification of the DVRFS transient ground-water model is discussed for two common uses of the Death Valley regional ground-water flow system model: predictive pumping scenarios that extend beyond the end of the model simulation period (1998), and model simulations with only steady-state conditions.

  5. A new relation between pressure and fractional flow in two-phase flow in porous media

    E-Print Network [OSTI]

    Henning Arendt Knudsen; Alex Hansen

    2002-01-30T23:59:59.000Z

    We study average flow properties in porous media using a two-dimensional network simulator. It models the dynamics of two-phase immiscible bulk flow where film flow can be neglected. The boundary conditions are biperiodic which provide a means of studying steady state flow where complex bubble dynamics dominate the flow picture. We find fractional flow curves and corresponding pressure curves for different capillary numbers. In particular, we study the case of the two phases having equal viscosity. In this case we find that the derivative of the fractional flow with respect to saturation is related to the global pressure drop. This result can also be expressed in terms of relative permeabilities or mobilities, resulting in an equation tying together the mobilities of the two phases.

  6. Assistance Focus: Latin America/Caribbean (Brochure)

    SciTech Connect (OSTI)

    Not Available

    2015-01-01T23:59:59.000Z

    The Clean Energy Solutions Center Ask an Expert service connects governments seeking policy information and advice with one of more than 30 global policy experts who can provide reliable and unbiased quick-response advice and information. The service is available at no cost to government agency representatives from any country and the technical institutes assisting them. This publication presents summaries of assistance provided to African governments, including the benefits of that assistance.

  7. Assistance Focus: Asia/Pacific Region (Brochure)

    SciTech Connect (OSTI)

    Not Available

    2015-01-01T23:59:59.000Z

    The Clean Energy Solutions Center Ask an Expert service connects governments seeking policy information and advice with one of more than 30 global policy experts who can provide reliable and unbiased quick-response advice and information. The service is available at no cost to government agency representatives from any country and the technical institutes assisting them. This publication presents summaries of assistance provided to governments in the Asia/Pacific region, including the benefits of that assistance.

  8. Precision electron flow measurements in a disk transmission line.

    SciTech Connect (OSTI)

    Clark, Waylon T.; Pelock, Michael D.; Martin, Jeremy Paul; Jackson, Daniel Peter Jr.; Savage, Mark Edward; Stoltzfus, Brian Scott; Mendel, Clifford Will, Jr.; Pointon, Timothy David

    2008-01-01T23:59:59.000Z

    An analytic model for electron flow in a system driving a fixed inductive load is described and evaluated with particle in cell simulations. The simple model allows determining the impedance profile for a magnetically insulated transmission line given the minimum gap desired, and the lumped inductance inside the transition to the minimum gap. The model allows specifying the relative electron flow along the power flow direction, including cases where the fractional electron flow decreases in the power flow direction. The electrons are able to return to the cathode because they gain energy from the temporally rising magnetic field. The simulations were done with small cell size to reduce numerical heating. An experiment to compare electron flow to the simulations was done. The measured electron flow is {approx}33% of the value from the simulations. The discrepancy is assumed to be due to a reversed electric field at the cathode because of the inductive load and falling electron drift velocity in the power flow direction. The simulations constrain the cathode electric field to zero, which gives the highest possible electron flow.

  9. TOUGH+Hydrate v1.0 User's Manual: A Code for the Simulation of System Behavior in Hydrate-Bearing Geologic Media

    E-Print Network [OSTI]

    Moridis, George

    2008-01-01T23:59:59.000Z

    Behavior of Naturally Fractured Reservoirs, Soc. Pet. Eng.Flow Simulations in Fractured Reservoirs, Lawrence BerkeleyFor any given fractured reservoir flow problem, selection of

  10. 7. Simulations of PlasmaPhysical Processes in Clusters

    E-Print Network [OSTI]

    Boehringer, Hans

    . These simulations will be used as a stepping stone for future 3D simulations of the evolution of magnetized cooling Implications for Magnetic Cooling Flow Cluster Cores Christopher J. Garasi 1;2 and Jean A. Eilek 3 1 Sandia in order to provide insight into the evolution of tur­ bulent, cooling flow cluster cores. It is believed

  11. American Recovery and Reinvestment Act, Financial Assistance...

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

    - ARRAAttachment3.rtf FOIA Frequently Requested Documents: DE-EE0002884 Recovery Act - Integrated Algal Biorefinery (IABR) Financial Assistance Funding Opportunity Announcement...

  12. ESPC ENABLE Project Assistance and Training

    Broader source: Energy.gov [DOE]

    The Federal Energy Management Program (FEMP) offers project assistance and training to help Federal agencies implement Energy Savings Performance Contracts (ESPC) ENABLE projects.

  13. Plasma Assisted Catalysis System for NOx Reduction

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

    2 NOXTECH NOXTECH PLASMA ASSISTED CATALYSIS SYSTEM FOR NOx REDUCTION BY NOXTECH With the Support & Cooperation of DOE Noxtech, Inc. *Delaware Corporation registered to do business...

  14. Radiological Assistance Program | National Nuclear Security Administra...

    National Nuclear Security Administration (NNSA)

    remains with the owner of the radioactive material. RAP team member surveying a vehicle Additionally, RAP provides emergency response training assistance to federal, state,...

  15. Air Emissions Reduction Assistance Program (Iowa) | Department...

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

    Provider Iowa Department of Natural Resources The State of Iowa may provide financial assistance in the form of loans andor grants to projects aimed at reducing air emissions...

  16. Renewable Energy Project Assistance | Department of Energy

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

    The Federal Energy Management Program (FEMP) provides renewable energy project assistance to help Federal agencies identify and implement renewable energy technologies into...

  17. Energy Innovation Assistance Program (EIAP) (Quebec, Canada)

    Broader source: Energy.gov [DOE]

    The Energy innovation assistance program (PAIE) aims to encourage the development of new technologies or innovative processes focusing on energy efficiency or emerging energy sources by financially...

  18. Employee Assistance Self-ID Form

    Office of Environmental Management (EM)

    assigned assistant, the Program Office Safety and Health Representative, the Health Clinic, and the Incident Management Team). The information may be aggregated into lists,...

  19. Weatherization Assistance Program - The American Recovery and...

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

    and if indicated, replacement of the same; mitigating air infiltration; and reducing electric base load consumption. Training and Technical Assistance At the national level,...

  20. THE DOE GUIDE TO FINANCIAL ASSISTANCE

    Office of Environmental Management (EM)

    as the Energy Policy Acts of 1992 and 2005 (EPAct), also provide authority for DOE to enter into financial assistance agreements. Generally, these statutes will identify the...

  1. USDA- Repowering Assistance Biorefinery Program (Federal)

    Broader source: Energy.gov [DOE]

    The Repowering Assistance Program provides payments to eligible biorefineries to replace fossil fuels used to produce heat or power to operate the biorefineries with renewable biomass....

  2. Research Assistant (Econometrics Specialist) -Centro de Estudios Puertorriqueos Job Title: Research Assistant (Econometrics Specialist)

    E-Print Network [OSTI]

    Qiu, Weigang

    Research Assistant (Econometrics Specialist) - Centro de Estudios Puertorriqueños Job Title: Research Assistant (Econometrics Specialist) ­ Centro de Estudios Puertorriqueños Job ID: 10155 Location related field is preferred. Training in econometrics and experience in applying econometrics are required

  3. Intelligent interface for design and simulation

    SciTech Connect (OSTI)

    Draisin, W.; Peter, E.

    1986-01-01T23:59:59.000Z

    We are developing a system composed of intelligent interfaces, expert systems, and databases that uses artificial intelligence techniques to simplify the use of large simulation codes and to help design complicated physical devices. The simulation codes are used in analyzing and designing weapons, and the devices are themselves parts of weapon systems. From a designer's point of view, the simulation process is the same no matter what is being simulated. In the course of developing two intelligent interfaces for the design of nuclear weapons, we have found that data-driven programming is a useful technique for implementing an open-ended user interface to assist the designer. We discuss the simulation process as it is done now and as it could be done with intelligent interfaces. We then discuss the use of data-driven programming in a database environment to support an interface for an arbitrary number of simulation codes. 3 figs.

  4. IEEE PES WM Panel on Modeling, Simulation and Applications of FACTS Controllers in Angle and Voltage Stability Studies, Singapore, Jan. 2000 Power Flow and Transient Stability Models of FACTS Controllers

    E-Print Network [OSTI]

    Cañizares, Claudio A.

    power ow and tran- sient stability studies of such system with its controllers. The latter and Voltage Stability Studies, Singapore, Jan. 2000 Power Flow and Transient Stability Models of FACTS|This paper presents transient stability and power ow models of Thyristor ControlledReactor TCR and Voltage

  5. Flow reversal power limit for the HFBR

    SciTech Connect (OSTI)

    Cheng, Lap Y.; Tichler, P.R.

    1995-10-01T23:59:59.000Z

    The High Flux Beam Reactor (HFBR) undergoes a buoyancy-driven reversal of flow in the reactor core following certain postulated accidents. Uncertainties about the afterheat removal capability during the flow reversal has limited the reactor operating power to 30 MW. An experimental and analytical program to address these uncertainties is described in this report. The experiments were single channel flow reversal tests under a range of conditions. The analytical phase involved simulations of the tests to benchmark the physical models and development of a criterion for dryout. The criterion is then used in simulations of reactor accidents to determine a safe operating power level. It is concluded that the limit on the HFBR operating power with respect to the issue of flow reversal is in excess of 60 MW.

  6. Health Resources Employee Assistance Program

    E-Print Network [OSTI]

    Fraden, Seth

    Generation of Cognitive Behavior (Playing Chess, etc.) · Involvement of Entire Perceptual-Cognitive System Busters Stressed at work? Stressed at home? Did you know that stress is now the #1 reason behind sickness and flow of your breath. This calms the body. · Imagine an energy bubble, like a balloon, around you

  7. K. A. Thole^ Assistant Professor.

    E-Print Network [OSTI]

    Thole, Karen A.

    . Institut fur Thermische Stromungsmaschinen, Universitat Karlsruhe, Karlsruhe, Germany Effect of a Crossflow at the Entrance to a Film-Cooling Hole Understanding the complex flow ofjets issuing into a crossflow from where the jet interacted with the crossflow at the hole exit. The results show that for entrance

  8. Plug flow and the breakdown of Bagnold scaling in cohesive granular flows

    E-Print Network [OSTI]

    Robert Brewster; Gary S. Grest; James W. Landry; Alex J. Levine

    2005-09-05T23:59:59.000Z

    Cohesive granular media flowing down an inclined plane are studied by discrete element simulations. Previous work on cohesionless granular media demonstrated that within the steady flow regime where gravitational energy is balanced by dissipation arising from intergrain forces, the velocity profile in the flow direction scales with depth in a manner consistent with the predictions of Bagnold. Here we demonstrate that this Bagnold scaling does not hold for the analogous steady-flows in cohesive granular media. We develop a generalization of the Bagnold constitutive relation to account for our observation and speculate as to the underlying physical mechanisms responsible for the different constitutive laws for cohesive and noncohesive granular media.

  9. A penalization method for calculating the flow beneath travelling water waves of large amplitude

    E-Print Network [OSTI]

    Adrian Constantin; Konstantinos Kalimeris; Otmar Scherzer

    2014-08-08T23:59:59.000Z

    A penalization method for a suitable reformulation of the governing equations as a constrained optimization problem provides accurate numerical simulations for large-amplitude travelling water waves in irrotational flows and in flows with constant vorticity.

  10. Anisotropic flow in striped superhydrophobic channels

    E-Print Network [OSTI]

    Zhou, Jiajia; Schmid, Friederike; Vinogradova, Olga I

    2012-01-01T23:59:59.000Z

    We report results of dissipative particle dynamics simulations and develop a semi-analytical theory and of an anisotropic flow in a parallel-plate channel with two superhydrophobic striped walls. Our approach is valid for any local slip at the gas sectors and an arbitrary distance between the plates, ranging from a thick to a thin channel. It allows us to optimize area fractions, slip lengths, channel thickness and texture orientation to maximize a transverse flow. Our results may be useful for extracting effective slip tensors from global measurements, such as the permeability of a channel, in experiments or simulations, and may also find applications in passive microfluidic mixing.

  11. Anisotropic flow in striped superhydrophobic channels

    E-Print Network [OSTI]

    Jiajia Zhou; Aleksey V. Belyaev; Friederike Schmid; Olga I. Vinogradova

    2012-05-02T23:59:59.000Z

    We report results of dissipative particle dynamics simulations and develop a semi-analytical theory of an anisotropic flow in a parallel-plate channel with two superhydrophobic striped walls. Our approach is valid for any local slip at the gas sectors and an arbitrary distance between the plates, ranging from a thick to a thin channel. It allows us to optimize area fractions, slip lengths, channel thickness and texture orientation to maximize a transverse flow. Our results may be useful for extracting effective slip tensors from global measurements, such as the permeability of a channel, in experiments or simulations, and may also find applications in passive microfluidic mixing.

  12. Low volume flow meter

    DOE Patents [OSTI]

    Meixler, Lewis D. (East Windsor, NJ)

    1993-01-01T23:59:59.000Z

    The low flow monitor provides a means for determining if a fluid flow meets a minimum threshold level of flow. The low flow monitor operates with a minimum of intrusion by the flow detection device into the flow. The electrical portion of the monitor is externally located with respect to the fluid stream which allows for repairs to the monitor without disrupting the flow. The electronics provide for the adjustment of the threshold level to meet the required conditions. The apparatus can be modified to provide an upper limit to the flow monitor by providing for a parallel electronic circuit which provides for a bracketing of the desired flow rate.

  13. Chemically assisted mechanical refrigeration process

    DOE Patents [OSTI]

    Vobach, A.R.

    1987-11-24T23:59:59.000Z

    There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing the evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator. 5 figs.

  14. Chemically assisted mechanical refrigeration process

    DOE Patents [OSTI]

    Vobach, Arnold R. (6006 Allentown Dr., Spring, TX 77389)

    1987-01-01T23:59:59.000Z

    There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer (11) at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer (11) to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator (10) to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing the evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator.

  15. Chemically assisted mechanical refrigeration process

    DOE Patents [OSTI]

    Vobach, Arnold R. (6006 Allentown Dr., Spring, TX 77379)

    1987-01-01T23:59:59.000Z

    There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer (11) at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer (11) to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator (10) to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing he evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator.

  16. Chemically assisted mechanical refrigeration process

    DOE Patents [OSTI]

    Vobach, A.R.

    1987-06-23T23:59:59.000Z

    There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing the evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator. 5 figs.

  17. Consulting Assistance on Economic Discussion Papers

    E-Print Network [OSTI]

    Consulting Assistance on Economic Reform II Discussion Papers The objectives of the Consulting Assistance on Economic Reform (CAER II) project are to contribute to broad-based and sustainable economic, Bureau for Global Programs, Field Support and Research, Center for Economic Growth and Agricultural

  18. Effective Community-Wide Policy Technical Assistance

    E-Print Network [OSTI]

    Effective Community-Wide Policy Technical Assistance: The DOE/NREL Approach NREL is a national: The DOE/NREL Approach Effective Community-Wide Policy Technical Assistance: The DOE/NREL Approach HelpingVoss, Sarah Busche, Eric Lantz, Lynn Billman, and Dan Beckley. The layout and technical editing were

  19. Instructions for use JICA's Assistance in Health

    E-Print Network [OSTI]

    Tsunogai, Urumu

    and clinical care eg, strengthen health systems including the development of human resources, facilitiesInstructions for use #12;1 JICA's Assistance in Health Ryuji MATSUNAGA International Cooperation's Assistance in Health Example of JICA Programme/Projects 2 #12;An Overview of Japan's ODA 3 #12;Japan's ODA

  20. Spanish & Portuguese -Teaching Assistants Spring 2014

    E-Print Network [OSTI]

    Wisconsin at Madison, University of

    Spanish & Portuguese - Teaching Assistants Spring 2014 Abreu-González, Kallie ........................................................................................ 2-3128 Spanish 102 Head TA pananth@wisc.edu 770 Van Hise Hall Office Hours: 9:55 ­ 10:55 MR Teach 383 VH #12;Spanish & Portuguese - Teaching Assistants Spring 2014 Beltrán, Edith

  1. Renewable Energy Project Development Assistance (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2013-07-01T23:59:59.000Z

    This fact sheet provides information on the Tribes selected to receive assistance from the U.S. Department of Energy Office of Indian Energy 2013 Strategic Technical Assistance Response Team (START) Program, which provides technical expertise to support the development of next-generation energy projects on tribal lands.

  2. AGREEMENT FOR DOE-FUNDED TECHNOLOGY ASSISTANCE

    E-Print Network [OSTI]

    National Laboratory, agrees to provide the Technology services described below at no cost to the REQUESTERAGREEMENT FOR DOE-FUNDED TECHNOLOGY ASSISTANCE Date: Agreement: TO: FROM: Battelle Memorial Title: Field of Use: The activities to be performed under this Technology assistance will be: BATTELLE

  3. Assistant or Associate Professor in Sedimentology

    E-Print Network [OSTI]

    Assistant or Associate Professor in Sedimentology The Department of Earth Sciences (DES), Mineral for a tenure-track Assistant or Associate Professor position in Sedimentology to begin in July 2015. We seek an innovative individual with excellent teaching and research skills in sedimentology. Expertise in Precambrian

  4. Modelling of Depletion-Induced Microseismic Events by Coupled Reservoir Simulation: Application to Valhall Field

    E-Print Network [OSTI]

    fractures/faults. A flow-deformation coupled reservoir geomechanical modelling approach has been applied. Coupled 3D geomechanical (deformation and fluid flow) simulations for Valhall field were conducted. Well in flow rate correlations in the field). The coupled 3D geomechanical simulation provides a tool

  5. Oxygen-assisted multipass cutting of carbon fiber reinforced plastics with ultra-short laser pulses

    SciTech Connect (OSTI)

    Kononenko, T. V.; Komlenok, M. S.; Konov, V. I. [Natural Sciences Center, General Physics Institute, Vavilov str. 38, 119991 Moscow (Russian Federation); National Research Nuclear University, “MEPhI,” Kashirskoye shosse 31, 115409 Moscow (Russian Federation); Freitag, C. [Universität Stuttgart, Institut für Strahlwerkzeuge (IFSW), Pfaffenwaldring 43, 70569 Stuttgart (Germany); GSaME Graduate School of Excellence Advanced Manufacturing Engineering, Nobelstrasse 12, 70569 Stuttgart (Germany); Onuseit, V.; Weber, R.; Graf, T. [Universität Stuttgart, Institut für Strahlwerkzeuge (IFSW), Pfaffenwaldring 43, 70569 Stuttgart (Germany)

    2014-03-14T23:59:59.000Z

    Deep multipass cutting of bidirectional and unidirectional carbon fiber reinforced plastics (CFRP) with picosecond laser pulses was investigated in different static atmospheres as well as with the assistance of an oxygen or nitrogen gas flow. The ablation rate was determined as a function of the kerf depth and the resulting heat affected zone was measured. An assisting oxygen gas flow is found to significantly increase the cutting productivity, but only in deep kerfs where the diminished evaporative ablation due to the reduced laser fluence reaching the bottom of the kerf does not dominate the contribution of reactive etching anymore. Oxygen-supported cutting was shown to also solve the problem that occurs when cutting the CFRP parallel to the fiber orientation where a strong deformation and widening of the kerf, which temporarily slows down the process speed, is revealed to be typical for processing in standard air atmospheres.

  6. Numerical studies on two-way coupled fluid flow and geomechanics in hydrate deposits

    E-Print Network [OSTI]

    Kim, J.

    2014-01-01T23:59:59.000Z

    A. 2008. Modeling of Geomechanics in Naturally Fracturedcoupling porous flow and geomechanics. Soc. Pet. Eng. J. 11(a reservoir simulator and a geomechanics module. Soc. Pet.

  7. A correction function method to solve incompressible fluid flows to high accuracy with immersed geometries

    E-Print Network [OSTI]

    Marques, Alexandre Noll

    2012-01-01T23:59:59.000Z

    Numerical simulations of incompressible viscous flows in realistic configurations are increasingly important in many scientific and engineering fields. In Aeronautics, for instance, relatively cheap numerical computations ...

  8. Well correction factors for three-dimensional reservoir simulation

    E-Print Network [OSTI]

    Fjerstad, Paul Albert

    1985-01-01T23:59:59.000Z

    of Advisory Committee: Dr. W. D. Von Gonten A three-dimensional reservoir simulation model does not calculate the correct bottomhole flowing pressure, p f, for a partially penetrating well. The simulator well cell pressure must be corrected ro obtain... an accurate value for p f. Simulation model results have wf' been used in this part to develop a new inflow equation relating cell pressure to actual bottomhole flowing pressure for a partially penetrating well. Based on the new inflow equation, an equation...

  9. RELAP5 subcooled critical flow model verification

    SciTech Connect (OSTI)

    Petelin, S.; Gortnar, O.; Mavko, B. (Institut Jozef Stefan, Ljubljana (Solomon Islands))

    1993-01-01T23:59:59.000Z

    We discuss some results of the RELAP5 break modeling during the analysis of International Standard Problem 27 (ISP-27) performed on the BETHSY facility. This study deals with the discontinuity of the RELAP5 critical flow prediction in a strongly subcooled region. Such unrealistic behavior was observed during the pretest simulations of ISP-27. Based on the investigation, a RELAP5 code correction is suggested that ensures a more appropriate simulation of the critical discharge of strongly subcooled liquid.

  10. Bacteria in shear flow

    E-Print Network [OSTI]

    Marcos, Ph.D. Massachusetts Institute of Technology

    2011-01-01T23:59:59.000Z

    Bacteria are ubiquitous and play a critical role in many contexts. Their environment is nearly always dynamic due to the prevalence of fluid flow: creeping flow in soil, highly sheared flow in bodily conduits, and turbulent ...

  11. Dispersed flow film boiling

    E-Print Network [OSTI]

    Yoder, Graydon L.

    1980-01-01T23:59:59.000Z

    Dispersed flow consists of small liquid droplets entrained in a flowing vapor. This flow regime can occur in cryogenic equipment, in steam generators, and during nuclear reactor loss of coolant accidents. A theoretical ...

  12. Building Galaxies with Simulations

    E-Print Network [OSTI]

    Romeel Davé; Kristian Finlator; Lars Hernquist; Neal Katz; Dušan Kereš; Casey Papovich; David H. Weinberg

    2005-10-20T23:59:59.000Z

    We present an overview of some of the issues surrounding current models of galaxy formation, highlighting recent insights obtained from cosmological hydrodynamic simulations. Detailed examination of gas accretion processes show a hot mode of gas cooling from near the halo's virial temperature, and a previously underappreciated cold mode where gas flows in along filaments on dynamical timescales, emitting its energy in line radiation. Cold mode dominates in systems with halo masses slightly smaller than the Milky Way and below, and hence dominates the global accretion during the heydey of galaxy formation. This rapid accretion path enables prompt assembly of massive galaxies in the early universe, and results in $z\\sim 4$ galaxy properties in broad agreement with observations, with the most massive galaxies being the most rapid star formers. Massive galaxies today are forming stars at a much reduced rate, a trend called downsizing. The trend of downsizing is naturally reproduced in simulations, owing to a transition from cold mode accretion in the early growth phase to slower hot mode accretion once their halos grow large. However, massive galaxies at the present epoch are still observed to have considerably redder colors than simulations suggest, suggesting that star formation is not sufficiently truncated in models by the transition to hot mode, and that another process not included in current simulations is required to suppress star formation.

  13. Flow Partitioning in Fully Saturated Soil Aggregates

    SciTech Connect (OSTI)

    Yang, Xiaofan; Richmond, Marshall C.; Scheibe, Timothy D.; Perkins, William A.; Resat, Haluk

    2014-03-30T23:59:59.000Z

    Microbes play an important role in facilitating organic matter decomposition in soils, which is a major component of the global carbon cycle. Microbial dynamics are intimately coupled to environmental transport processes, which control access to labile organic matter and other nutrients that are needed for the growth and maintenance of microorganisms. Transport of soluble nutrients in the soil system is arguably most strongly impacted by preferential flow pathways in the soil. Since the physical structure of soils can be characterized as being formed from constituent micro aggregates which contain internal porosity, one pressing question is the partitioning of the flow among the “inter-aggregate” and “intra-aggregate” pores and how this may impact overall solute transport within heterogeneous soil structures. The answer to this question is particularly important in evaluating assumptions to be used in developing upscaled simulations based on highly-resolved mechanistic models. We constructed a number of diverse multi-aggregate structures with different packing ratios by stacking micro-aggregates containing internal pores and varying the size and shape of inter-aggregate pore spacing between them. We then performed pore-scale flow simulations using computational fluid dynamics methods to determine the flow patterns in these aggregate-of-aggregates structures and computed the partitioning of the flow through intra- and inter-aggregate pores as a function of the spacing between the aggregates. The results of these numerical experiments demonstrate that soluble nutrients are largely transported via flows through inter-aggregate pores. Although this result is consistent with intuition, we have also been able to quantify the relative flow capacity of the two domains under various conditions. For example, in our simulations, the flow capacity through the aggregates (intra-aggregate flow) was less than 2% of the total flow when the spacing between the aggregates was larger than 18 micron. Inter-aggregate pores continued to be the dominant flow pathways even at much smaller spacing; intra-aggregate flow was less than 10% of the total flow when the inter- and intra-aggregate pore sizes were comparable. Such studies are making it possible to identify which model upscaling assumptions are realistic and what computational methods are required for detailed numerical investigation of microbial carbon cycling dynamics in soil systems.

  14. Friction and the oscillatory motion of granular flows

    E-Print Network [OSTI]

    Lydie Staron

    2012-11-26T23:59:59.000Z

    This contribution reports on numerical simulations of 2D granular flows on erodible beds. The broad aim is to investigate whether simple flows of model granular matter exhibits spontaneous oscillatory motion in generic flow conditions, and in this case, whether the frictional properties of the contacts between grains may affect the existence or the characteristics of this oscillatory motion. The analysis of different series of simulations show that the flow develops an oscillatory motion with a well-defined frequency which increases like the inverse of the velocity's square root. We show that the oscillation is essentially a surface phenomena. The amplitude of the oscillation is higher for lower volume fractions, and can thus be related to the flow velocity and grains friction properties. The study of the influence of the periodic geometry of the simulation cell shows no significant effect. These results are discussed in relation to sonic sands.

  15. Supporting Statement: OE Recovery Act Financial Assistance Grants...

    Energy Savers [EERE]

    Supporting Statement: OE Recovery Act Financial Assistance Grants OMB Control Number 1910-5149 Supporting Statement: OE Recovery Act Financial Assistance Grants OMB Control Number...

  16. assisted distal gastrectomy: Topics by E-print Network

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

    of Vermont USA 5. 112000-12312004: Graduate Research Assistant, Department of Civil Engineering, University of Vermont, Vermont, USA III Jacobs, Laurence J. 83 ASSISTED...

  17. assisted peritoneal dialysis: Topics by E-print Network

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

    of Vermont USA 5. 112000-12312004: Graduate Research Assistant, Department of Civil Engineering, University of Vermont, Vermont, USA III Jacobs, Laurence J. 102 ASSISTED...

  18. NA 15 - Assistant Deputy Administrator for Secure Transportation...

    National Nuclear Security Administration (NNSA)

    Us Our Operations Management and Budget Office of Civil Rights Workforce Statistics NA 15 - Assistant Deputy Administrator for ... NA 15 - Assistant Deputy...

  19. Hydrogen Assisted Diesel Combustion in a Common Rail Turbodiesel...

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

    Assisted Diesel Combustion in a Common Rail Turbodiesel Engine Hydrogen Assisted Diesel Combustion in a Common Rail Turbodiesel Engine This study measured the effects of hydrogen...

  20. Combustion, Efficiency, and Fuel Effects in a Spark-Assisted...

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

    Combustion, Efficiency, and Fuel Effects in a Spark-Assisted HCCI Gasoline Engine Combustion, Efficiency, and Fuel Effects in a Spark-Assisted HCCI Gasoline Engine 2004 Diesel...