Numerical simulation of electrokinetically driven micro flows
Hahm, Jungyoon
2005-11-01T23:59:59.000Z
Spectral element based numerical solvers are developed to simulate electrokinetically driven flows for micro-fluidic applications. Based on these numerical solvers, basic phenomena and devices for electrokinetic applications in micro and nano flows...
Simulation- Assisted Audit of an Air Conditioned Office Building
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....
Mesoscale simulations of particulate flows with parallel distributed...
Office of Scientific and Technical Information (OSTI)
Journal Article: Mesoscale simulations of particulate flows with parallel distributed Lagrange multiplier technique Citation Details In-Document Search Title: Mesoscale simulations...
Model Order Reduction in Porous Media Flow Simulation and Optimization
Ghasemi, Mohammadreza
2015-05-06T23:59:59.000Z
Subsurface flow modeling and simulation is ubiquitous in many energy related processes, including oil and gas production. These models are usually large scale and simulating them can be very computationally demanding, particularly in work-flows...
Numerical Simulation of Laminar Reacting Flows with Complex Chemistry
Bell, John B.
Numerical Simulation of Laminar Reacting Flows with Complex Chemistry M S Day and J B Bell Lawrence Simulation of Laminar Reacting Flows 2 1. Introduction Detailed modelling of time-dependent reacting ows
Adaptive LES Methodology for Turbulent Flow Simulations
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.
Atrioventricular blood flow simulation based on patient-specific data
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
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...
Direct Numerical Simulation of the Flow in a Pebble Bed
Ward, Paul
2014-06-24T23:59:59.000Z
at Argonne National Laboratory, to conduct both large eddy simulation (LES) and direct numerical simulation (DNS) of fluid flow through a single face-centered cubic sphere lattice with periodic boundary conditions. Multiple LES were conducted with varying...
Numerical Simulation of Laminar Reacting Flows with Complex Chemistry
Bell, John B.
Numerical Simulation of Laminar Reacting Flows with Complex Chemistry M S Day and J B Bell Lawrence: 47.40.Fw, 82.40.Py Submitted to: Combust. Theory Modelling #12;Numerical Simulation of Laminar
Direct numerical simulation of turbulent reacting flows
Chen, J.H. [Sandia National Laboratories, Livermore, CA (United States)
1993-12-01T23:59:59.000Z
The development of turbulent combustion models that reflect some of the most important characteristics of turbulent reacting flows requires knowledge about the behavior of key quantities in well defined combustion regimes. In turbulent flames, the coupling between the turbulence and the chemistry is so strong in certain regimes that is is very difficult to isolate the role played by one individual phenomenon. Direct numerical simulation (DNS) is an extremely useful tool to study in detail the turbulence-chemistry interactions in certain well defined regimes. Globally, non-premixed flames are controlled by two limiting cases: the fast chemistry limit, where the turbulent fluctuations. In between these two limits, finite-rate chemical effects are important and the turbulence interacts strongly with the chemical processes. This regime is important because industrial burners operate in regimes in which, locally the flame undergoes extinction, or is at least in some nonequilibrium condition. Furthermore, these nonequilibrium conditions strongly influence the production of pollutants. To quantify the finite-rate chemistry effect, direct numerical simulations are performed to study the interaction between an initially laminar non-premixed flame and a three-dimensional field of homogeneous isotropic decaying turbulence. Emphasis is placed on the dynamics of extinction and on transient effects on the fine scale mixing process. Differential molecular diffusion among species is also examined with this approach, both for nonreacting and reacting situations. To address the problem of large-scale mixing and to examine the effects of mean shear, efforts are underway to perform large eddy simulations of round three-dimensional jets.
Methods for Numerical Flow Simulation Rolf Rannacher
models of laminar hemodynamical flows. We discuss space and time dis- cretization with emphasis as flow control and model calibration. We concen- trate on laminar flows in which all relevant spatial-Stokes equations The continuum mechanical model of the flow of a viscous Newtonian fluid is the system
Numerical simulation of electrokinetically driven micro flows
Hahm, Jungyoon
2005-11-01T23:59:59.000Z
to control mixed electroosmotic/pressure driven flow in the grooved micro-channel. The controlled flow pattern enables entrapment and release of prescribed amounts of scalar species in the grooves. As another application, hydrodynamic/ electrokinetic focusing...
Numerical simulation of flow separation control by oscillatory fluid injection
Resendiz Rosas, Celerino
2005-08-29T23:59:59.000Z
In this work, numerical simulations of flow separation control are performed. The sep-aration control technique studied is called 'synthetic jet actuation'. The developed code employs a cell centered finite volume scheme which handles viscous...
Simulation of bilinear flow in single matrix block drainage
Branajaya, Romi Triaji
2005-02-17T23:59:59.000Z
This thesis presents modeling of bilinear flow in tight gas wells and its behavior on single matrix block drainage. The objectives of this research are to: simulate a tight gas well using matrix block drainage under constant production pwf...
Implicit runge-kutta methods to simulate unsteady incompressible flows
Ijaz, Muhammad
2009-05-15T23:59:59.000Z
A numerical method (SIMPLE DIRK Method) for unsteady incompressible viscous flow simulation is presented. The proposed method can be used to achieve arbitrarily high order of accuracy in time-discretization which is otherwise limited to second order...
Direct Numerical Simulation of the Flow in a Pebble Bed
Ward, Paul
2014-06-24T23:59:59.000Z
bed reactors: dust generation and scaling, proceedings of ICAPP 2012, Chicago, June 24–28, 2012 [3] A. Shams, F. Roelofs, EMJ. Komen, E. Baglietto, 2013. “Quasi-direct numerical simulation of a pebble bed configuration. Part I: Flow (velocity...
Economic evaluation of mine assisted oil recovery using a reservoir simulator
Fontaine, Russell Charles
1985-01-01T23:59:59.000Z
ECONOMIC EVALUATION OF MINE ASSISTED OIL RECOVERY USING A RESERVOIR SIMULATOR A Thesis by RUSSELL CHARLES FONTAINE Submitted to the Graduate College of Texas A 4 M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 1985 Major Subject: Petroleum Engineering ECONOMIC EVALUATION OF MINE ASSISTED OIL RECOVERY USING A RESERVOIR SIMULATOR A Thesis by RUSSELL CHARLES FONTAINE Approved as to style and content by: Richard A. tar zman...
Two-dimensional AMR simulations of colliding flows
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...
SIMULATING NON-DARCY FLOW THROUGH POROUS MEDIA USING SUNDANCE
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
Fluid Flow Simulation in Fractured Reservoirs
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 ...
Multiscale CFD simulations of entrained flow gasification
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, ...
Water and Mercury Pipe Flow Simulation in FLUENTSimulation in FLUENT
McDonald, Kirk
Water and Mercury Pipe Flow Simulation in FLUENTSimulation in FLUENT Yan Zhan, Foluso Ladeinde;Straight Pipe flow Ph i l bl-- Physical problem Isothermal mercury/ water flow through a 60D straight pipe* Mercury 1500 41.844 m 4.04 m/s 18.5 bar 15.67 bar Water 1500 331.404 m 4.04 m/s 18.5 bar 18.291bar *uave
Submarine landslide flows simulation through centrifuge modelling
Gue, Chang Shin
2012-05-08T23:59:59.000Z
) ...... . . . . . . . . 166 Figure 5.2: Illustration of DAM PM (after Abe, 2008) ............................................... 167 Figure 5.3: Condition of a unit of a mass in submerged case ........ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 Figure 5... height ph average prototype flow height i hydraulic Gradient K hydraulic conductivity k hydraulic permeability act/passk lateral stress coefficient L horizontal length or flow distance L max maximum runout distance M mass N Normal...
Simulation of noise-assisted transport via optical cavity networks
Filippo Caruso; Nicolò Spagnolo; Chiara Vitelli; Fabio Sciarrino; Martin B. Plenio
2010-10-26T23:59:59.000Z
Recently, the presence of noise has been found to play a key role in assisting the transport of energy and information in complex quantum networks and even in biomolecular systems. Here we propose an experimentally realizable optical network scheme for the demonstration of the basic mechanisms underlying noise-assisted transport. The proposed system consists of a network of coupled quantum optical cavities, injected with a single photon, whose transmission efficiency can be measured. Introducing dephasing in the photon path this system exhibits a characteristic enhancement of the transport efficiency that can be observed with presently available technology.
Mesoscale simulations of polymer dynamics in microchannel flows
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.
Integration of an Aggregate Flow Model with a Traffic Flow Simulator
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
FRAC-STIM: A Physics-Based Fracture Simulation, /reservoir Flow...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
FRAC-STIM: A Physics-Based Fracture Simulation, reservoir Flow and Heat Transport Simulator(aka FALCON) FRAC-STIM: A Physics-Based Fracture Simulation, reservoir Flow and Heat...
Hydrodynamic stability of inverted annular flow in an adiabatic simulation
DeJarlais, G.; Ishii, M.; Linehan, J.
1983-07-01T23:59:59.000Z
Inverted annular flow was simulated adiabatically with turbulent water jets, issuing downward from large aspect ratio nozzles, enclosed in gas annuli. Velocities, diameters, and gas species were varied, and core jet length, shape, break-up mode, and dispersed core droplet sizes were recorded at approximately 750 data points. Inverted annular flow destabilization lead to inverted slug flow at low relative velocities, and to dispersed droplet flow at high relative velocities. For both of these transitions from inverted annular flow, core break-up length correlations were developed by extending work on free liquid jets to include this coaxial, jet disintegration phenomenon. The results show length dependence upon D/SUB J/, Re/SUB J/, We/SUB J/, ..cap alpha.. and We/SUB G. Correlations for core shape, break-up mechanisms and dispersed core droplet size were also developed, by extending the results of free jet stability, roll wave entrainment, and churn turbulent droplet stability studies.
Hydrodynamic stability of inverted annular flow in an adiabatic simulation
De Jarlais, G.; Ishii, M.; Linehan, J.
1984-01-01T23:59:59.000Z
Inverted annular flow was simulated adiabatically with turbulent water jets, issuing downward from large aspect ratio nozzle, enclosed in gas annuli. Velocities, diameters, and gas species were varied, and core jet length, shape, break-up mode, and dispersed core droplet sizes were recorded at approximately 750 data points. Inverted annular flow destabilization lead to inverted slug flow at low relative velocities, and to dispersed droplet flow at high relative velocities. For both of these transitions from inverted annular flow, core break-up length correlations were developed by extending work on free liquid jets to include this coaxial, jet disintegration phenomenon. The results show length dependence upon D/sub J/, Re/sub J/, ..cap alpha.. and We/sub G, rel/. Correlations for core shape, break-up mechanisms and dispersed core droplet size were also developed, by extending the results of free jet stability, roll wave entrainment, and churn turbulent droplet stability studies.
Unstructured spectral element methods of simulation of turbulent flows
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.
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.
Simulation of salt migrations in density dependent groundwater flow
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
Computer simulation of flow past superhydrophobic striped surfaces
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
Hydrodynamic stability of inverted annular flow in an adiabatic simulation
De Jarlais, G.; Ishii, M.; Linehan, J.
1986-02-01T23:59:59.000Z
Inverted annular flow was simulated adiabatically with turbulent water jets, issuing downward from large aspect ratio nozzles, enclosed in gas annuli. Velocities, diameters, and gas species were varied, and core jet length, shape, breakup mode, and dispersed core droplet sizes were recorded at approximately 750 data points. Inverted annular flow destabilization led to inverted slug flow at low relative velocities, and to dispersed droplet flow, core breakup length correlations were developed by extending work on free liquid jets to include this coaxial, jet disintegration phenomenon. The results show length dependence upon D/sub J/, Re/sub J/, We/sub J/, ..cap alpha.., and We/sub G/,rel. Correlations for core shape, breakup mechanisms, and dispersed core droplet size were also developed, by extending the results of free jet stability, roll wave entrainment, and churn turbulent droplet stability studies.
Parallel Multiphysics Simulations of Charged Particles in Microfluidic Flows
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.
Simulations of ductile flow in brittle material processing
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.
A Study of mixing in computer simulated laminar flow systems
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...
GPU accelerated simulations of bluff body flows using vortex particle methods
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
Heat transfer and material flow during laser assisted multi-layer additive manufacturing
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.
Error estimation and anisotropic mesh refinement for 3d laminar aerodynamic flow simulations
Hartmann, Ralf
Error estimation and anisotropic mesh refinement for 3d laminar aerodynamic flow simulations Tobias-dimensional laminar aerodynamic flow simulations. The optimal order symmetric interior penalty discontinuous Galerkin laminar flows, see Sections 2 and 3 for the governing equations and the discretization
Multiscale Simulation Framework for Coupled Fluid Flow and Mechanical Deformation
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.
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.
An energy preserving formulation for the simulation of multiphase turbulent flows.
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
Rutqvist, J.
2011-01-01T23:59:59.000Z
geomechanics and reservoir simulation. Society of Petroleumporous flow and geomechanics. Society of Petroleum Engineers
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
Simulation of Flow and Transport at the Micro (Pore) Scale
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.
Mass and charge flow in nanopores: numerical simulation via mesoscale models
Cecconi, Fabio
Mass and charge flow in nanopores: numerical simulation via mesoscale models Mauro Chinappi1 at nanoscale is here addressed via a recent developed mesoscale approach. In particular the flow
An unstructured finite volume simulator for multiphase flow through fractured-porous media
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 ...
Tetrahedral hp finite elements: Algorithms and flow simulations
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.
Pore-Scale Simulation Of Experimentally Realizable, Oscillatory Flow In Porous Rock
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
Flume Studies of Sediment Transportation in Shallow Flow with Simulated Rainfall
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 ...
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...
GPU accelerated flow solver for direct numerical simulation of turbulent flows
Salvadore, Francesco [CASPUR – via dei Tizii 6/b, 00185 Rome (Italy)] [CASPUR – via dei Tizii 6/b, 00185 Rome (Italy); Bernardini, Matteo, E-mail: matteo.bernardini@uniroma1.it [Department of Mechanical and Aerospace Engineering, University of Rome ‘La Sapienza’ – via Eudossiana 18, 00184 Rome (Italy)] [Department of Mechanical and Aerospace Engineering, University of Rome ‘La Sapienza’ – via Eudossiana 18, 00184 Rome (Italy); Botti, Michela [CASPUR – via dei Tizii 6/b, 00185 Rome (Italy)] [CASPUR – via dei Tizii 6/b, 00185 Rome (Italy)
2013-02-15T23:59:59.000Z
Graphical processing units (GPUs), characterized by significant computing performance, are nowadays very appealing for the solution of computationally demanding tasks in a wide variety of scientific applications. However, to run on GPUs, existing codes need to be ported and optimized, a procedure which is not yet standardized and may require non trivial efforts, even to high-performance computing specialists. In the present paper we accurately describe the porting to CUDA (Compute Unified Device Architecture) of a finite-difference compressible Navier–Stokes solver, suitable for direct numerical simulation (DNS) of turbulent flows. Porting and validation processes are illustrated in detail, with emphasis on computational strategies and techniques that can be applied to overcome typical bottlenecks arising from the porting of common computational fluid dynamics solvers. We demonstrate that a careful optimization work is crucial to get the highest performance from GPU accelerators. The results show that the overall speedup of one NVIDIA Tesla S2070 GPU is approximately 22 compared with one AMD Opteron 2352 Barcelona chip and 11 compared with one Intel Xeon X5650 Westmere core. The potential of GPU devices in the simulation of unsteady three-dimensional turbulent flows is proved by performing a DNS of a spatially evolving compressible mixing layer.
Large Eddy Simulations of Combustor Liner Flows | Argonne Leadership...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
flow characteristics, representative of large-scale flow unsteadiness present in aircraft engines. Ultimately, the findings will be applied to an actual multi-cup General Electric...
Large-Eddy Simulation of a Turbulent Flow around a Multi-Perforated Plate
Mendez, Simon
Large-Eddy Simulation of a Turbulent Flow around a Multi-Perforated Plate Simon Mendez1 , Franck and used in Reynolds-Averaged Navier-Stokes methods cannot predict momen- tum/heat transfer on perforated plate are reported. Large-Eddy Simulations of the flow created by an infinite multi-perforated plate
Numerical simulation of flow and mixing behavior of solids on a moving grate combustion system
Columbia University
Numerical simulation of flow and mixing behavior of solids on a moving grate combustion system by #12;ii Numerical simulation of flow and mixing behavior of solids on a moving grate combustion system, and to a large extent influences the combustion process. Municipal solid waste (MSW) is not a uniform fuel
Friction dependence of shallow granular flows from discrete par-ticle simulations
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
LATEX TikZposter Simulation of two-phase flow for
Ábrahám, Erika
LATEX 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 University Concentrating solar thermal power plants Concentrating solar thermal power (CSP) plants
Drop breakup in the flow through fixed beds via stochastic simulation in model Gaussian fields
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
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
Numeric Simulation of Heat Transfer and Electrokinetic Flow in an Electroosmosis-Based
Le Roy, Robert J.
Numeric Simulation of Heat Transfer and Electrokinetic Flow in an Electroosmosis-Based Continuous is dedicated to under- standing the fluid flow and heat transfer mechanisms occurring in continuous flow PCR are discussed in detail. The importance of each heat transfer mechanism for different situations is also
Steam generators two phase flows numerical simulation with liquid and gas momentum equations
Paris-Sud XI, Université de
. The secondary flow is another loop that links the steam generator and the turbines. Inside the exchangerSteam generators two phase flows numerical simulation with liquid and gas momentum equations M Abstract This work takes place in steam generators flow studies and we consider here steady state three
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
Bluff Body Flow Simulation Using a Vortex Element Method
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.
A MONTE CARLO SIMULATION OF WATER FLOW IN VARIABLY ...
1910-10-30T23:59:59.000Z
derstanding and the prediction of water flow and contaminant transport ... conductivity (?) versus pressure head () and water content () versus must be specified.
GMINC - A MESH GENERATOR FOR FLOW SIMULATIONS IN FRACTURED RESERVOIRS
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
ON THE SIMULATION OF MULTICOMPONENT GAS FLOW IN POROUS MEDIA
Ewing, Richard E.
quadrilaterals as a solver to the nonÂDarcy flow equation, and a conservative GodunovÂtype 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 nonÂDarcy flow [9, 17, 13]. The mathematical nature
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...
Parallel Computing for the Simulation of 3D Free Surface Flows in Environmental Applications
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
Large-Eddy Simulation of Flow and Pollutant Transport in Urban Street Canyons with Ground Heating
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 ...
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 ...
Molecular dynamics simulations of oscillatory Couette flows with slip boundary conditions
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.
Molecular dynamics simulations of oscillatory Couette flows with slip boundary conditions
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.
Simulation of heavy oil reservoir performance using a non-Newtonian flow model
Narahara, Gene Masao
1983-01-01T23:59:59.000Z
SIMULATION OF HEAVY OIL RESERVOIR PERFORMANCE USING A NON-NEWTONIAN FLOW MODEL A Thesis by GENE MASAO NARAHARA Submitted to the Graduate College of Texas AILM University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE December 1983 Major Subject: Petroleum Engineering SIMULATION OF HEAVY OIL RESERVOIR PERFORMANCE USING A NON-NEWTONIAN FLOW MODEL A Thesis by GENE MASAO NARAHARA Approved as to style and content by: lng . U an of Committee) R. . Morse...
Probing protein orientation near charged nanosurfaces for simulation-assisted biosensor design
Christopher D. Cooper; Natalia C. Clementi; Lorena A. Barba
2015-08-20T23:59:59.000Z
Protein-surface interactions are ubiquitous in biological processes and bioengineering, yet are not fully understood. In biosensors, a key factor determining the sensitivity and thus the performance of the device is the orientation of the ligand molecules on the bioactive device surface. Adsorption studies thus seek to determine how orientation can be influenced by surface preparation. In this work, protein orientation near charged nanosurfaces is obtained under electrostatic effects using the Poisson-Boltzmann equation, in an implicit-solvent model. Sampling the free energy for protein GB1D4' at a range of tilt and rotation angles with respect to the charged surface, we calculated the probability of the protein orientations and observed a dipolar behavior. This result is consistent with published experimental studies and combined Monte Carlo and molecular dynamics simulations using this small protein, validating our method. More relevant to biosensor technology, antibodies such as immunoglobulin G are still a formidable challenge to molecular simulation, due to their large size. We obtained the probability distribution of orientations for the iso-type IgG2a at varying surface charge and salt concentration. This iso-type was not found to have a preferred orientation in previous studies, unlike the iso-type IgG1 whose larger dipole moment was assumed to make it easier to control. We find that the preferred orientation of IgG2a can be favorable for biosensing with positive surface charge of 0.05C/m$^{2}$ or higher and 37mM salt concentration. The results also show that local interactions dominate over dipole moment for this protein. Improving immunoassay sensitivity may thus be assisted by numerical studies using our method (and open-source code), guiding changes to fabrication protocols or protein engineering of ligand molecules to obtain more favorable orientations.
High Fidelity Simulation of Complex Suspension Flow for Practical...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
and John Kelso of the National Institute of Standards and Technology (NIST), and Marc Olano of NIST and the University of Maryland-Baltimore County. High Fidelity Simulation...
Numerical simulation of air/water multiphase flows for ceramic sanitary ware design by multiple GPUs
8 Numerical simulation of air/water multiphase flows for ceramic sanitary ware design by multiple and manufacturing of plumbing products such as ceramic sanitary wares. In order to re-produce the complex/water multiphase flows for ceramic sanitary ware design by multiple GPUs Being a world-wide leading company, TOTO
3-D Time-Accurate CFD Simulations of Wind Turbine Rotor Flow Fields
3-D Time-Accurate CFD Simulations of Wind Turbine Rotor Flow Fields Nilay Sezer-Uzol and Lyle N around the National Renewable Energy Laboratory (NREL) Phase VI horizontal axis wind turbine rotor. The 3 turbulent flow that generates the noise, in the context of the wind turbine application. I. Introduction
Stochastic numerical simulations of long term unsaturated flow in waste rock piles
Aubertin, Michel
Stochastic numerical simulations of long term unsaturated flow in waste rock piles O. Fala Genivar water flow in waste rock piles using selected realizations of stochastically distributed hydraulic term hydrogeological behaviour of waste rock piles, to help select the construction sequence
Simple Models of Zero-Net Mass-Flux Jets for Flow Control Simulations
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
Energy-Conserving Simulation of Incompressible Electro-Osmotic and Pressure-Driven Flow
Bowman,John C.
Energy-Conserving Simulation of Incompressible Electro-Osmotic and Pressure-Driven Flow Jahrul Alam in Theoretical and Computational Fluid Dynamics) Abstract. A numerical model for electro-osmotic flow asymmetric concentration profile that arises when an external pressure drop is imposed on electro-osmotic
Kochevsky, A N
2005-01-01T23:59:59.000Z
The paper describes capabilities of numerical simulation of liquid flows with solid and/or gas admixtures in centrifugal pumps using modern commercial CFD software packages, with the purpose to predict performance curves of the pumps treating such media. In particular, the approaches and multiphase flow models available in the package CFX-5 are described; their advantages and disadvantages are analyzed.
Sediment Transport in Shallow Subcritical Flow Disturbed by Simulated Rainfall
Machemehl, J. L.
1968-01-01T23:59:59.000Z
Studies were conducted in a closed system recirculating research flume to evaluate the relative effects of high intensity rainfall on von Karman's universal constant and the sediment transport capacity of shallow flow The tests in this study were...
Numerical simulation of three-dimensional electrical flow through geomaterials
Akhtar, Anwar Saeed
1998-01-01T23:59:59.000Z
95 99 V ELECTRICAL FLOW AROUND AN ELECTRICAL CONE PENETROMETER 104 5. 1 INTRODUCTION 5. 2 ANALYTICAL SOLUTION FOR ELECTRICAL FLOW AROUND AN ELECTRICAL CONE PENETROMETER 5. 3 NUMERICAL INVESTIGATION 5. 4 COMPARISON OF ANALYTICAL AND NUMERICAL... RESULTS 5. 5 CONCLUSION AND APPLICATION 5. 5. 1 Utilization of Numerical Results 104 106 110 113 115 116 VI EXPERIMENTAL EQUIPMENT DESIGN 121 6. 1 INTRODUCTION 6. 2 ELECTRICAL POWER SOURCE 6. 3 ELECTRICAL RESISTIVITY CONE PENETROMETER 6. 4...
Mechanistic Foam Flow Simulation in Heterogeneous and Multidimensional Porous Media
Patzek, Tadeusz W.
, and thermal reservoir simulator and created a fully functional, mechanistic foam simulator. Because foam, field-scale model for foam displacement is currently in use. The population-balance method for modeling that is analogous to energy and species mass balances7, 8. Accordingly, a separate conservation equation is written
On the Modeling and Simulation of Non-Hydrostatic Dam Break Flows
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
NUMERICAL SIMULATIONS OF LONG TERM UNSATURATED FLOW AND ACID MINE DRAINAGE AT WASTE ROCK PILES
Aubertin, Michel
NUMERICAL SIMULATIONS OF LONG TERM UNSATURATED FLOW AND ACID MINE DRAINAGE AT WASTE ROCK PILES Omar representative) waste rock piles and using observed climatic recharge data. The simulations were used to help are applied each year at the top of the piles, the water content profiles become periodic after a few years
Level Set Based Simulations of Two-Phase Oil-Water Flows in Pipes
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
van de Meent, Jan-Willem; Somfai, Ellak; Sultan, Eric; van Saarloos, Wim
2008-01-01T23:59:59.000Z
We present simulations of coherent structures in compressible flows near the transition to turbulence using the Dissipative Particle Dynamics (DPD) method. The structures we find are remarkably consistent with experimental observations and DNS simulations of incompressible flows, despite a difference in Mach number of several orders of magnitude. The bifurcation from the laminar flow is bistable and shifts to higher Reynolds numbers when the fluid becomes more compressible. This work underlines the robustness of coherent structures in the transition to turbulence and illustrates the ability of particle-based methods to reproduce complex non-linear instabilities.
Quantum Simulator for Transport Phenomena in Fluid Flows
Mezzacapo, A; Lamata, L; Egusquiza, I L; Succi, S; Solano, E
2015-01-01T23:59:59.000Z
Transport phenomena are one of the most challenging problems in computational physics. We present a quantum simulator based on pseudospin-boson quantum systems, which is suitable for encoding fluid dynamics problems within a lattice kinetic formalism. This quantum simulator is obtained by exploiting the analogies between Dirac and lattice Boltzmann equations. It is shown that both the streaming and collision processes of lattice Boltzmann dynamics can be implemented with controlled quantum operations, using a heralded quantum protocol to encode non-unitary scattering processes. The proposed simulator is amenable to realization in controlled quantum platforms, such as ion-trap quantum computers or circuit quantum electrodynamics processors.
Flow-History-Dependent Behavior in Entangled Polymer Melt Flow with Multiscale Simulation
Takahiro Murashima; Takashi Taniguchi
2011-10-05T23:59:59.000Z
Polymer melts represent the flow-history-dependent behavior. To clearly show this behavior, we have investigated flow behavior of an entangled polymer melt around two cylinders placed in tandem along the flow direction in a two dimensional periodic system. In this system, the polymer states around a cylinder in downstream side are different from the ones around another cylinder in upstream side because the former ones have a memory of a strain experienced when passing around the cylinder in upstream side but the latter ones do not have the memory. Therefore, the shear stress distributions around two cylinders are found to be different from each other. Moreover, we have found that the averaged flow velocity decreases accordingly with increasing the distance between two cylinders while the applied external force is constant. While this behavior is consistent with that of the Newtonian fluid, the flow-history-dependent behavior enhances the reduction of the flow resistance.
Numerical simulation of three-dimensional electrical flow through geomaterials
Akhtar, Anwar Saeed
1998-01-01T23:59:59.000Z
investigation results further validate this fact. DEDICATION To my parents, who desired it more for me than I did, and to my dearest wife Sofia and loving daughter Aneeka, who endured most of it. ACKNOWLEDGMENTS The author would like to express his... 46 46 50 50 50 51 52 53 54 57 57 58 59 60 62 64 65 67 70 CHAPTER IV ELECTRICAL FLOW THROUGH GEOMATERIALS WITH ELECTRODES AT GROUND SURFACE Page 73 4. 1 INTRODUCTION 4. 2 NUMERICAL INVESTIGATION OF ELECTRICAL FLOW THROUGH...
Pore-scale lattice Boltzmann simulation of laminar and turbulent flow through a sphere pack
Fattahia, Ehsan; Wohlmuth, Barbara; Rüde, Ulrich; Manhart, Michael; Helmig, Rainer
2015-01-01T23:59:59.000Z
The lattice Boltzmann method can be used to simulate flow through porous media with full geometrical resolution. With such a direct numerical simulation, it becomes possible to study fundamental effects which are difficult to assess either by developing macroscopic mathematical models or experiments. We first evaluate the lattice Boltzmann method with various boundary handling of the solid-wall and various collision operators to assess their suitability for large scale direct numerical simulation of porous media flow. A periodic pressure drop boundary condition is used to mimic the pressure driven flow through the simple sphere pack in a periodic domain. The evaluation of the method is done in the Darcy regime and the results are compared to a semi-analytic solution. Taking into account computational cost and accuracy, we choose the most efficient combination of the solid boundary condition and collision operator. We apply this method to perform simulations for a wide range of Reynolds numbers from Stokes flo...
FINITE ELEMENT METHODS FOR THE SIMULATION OF INCOMPRESSIBLE POWDER FLOW
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
Large Eddy Simulations of Jet Flow Interactions Within Rod Bundles
Salpeter, Nathaniel O.
2010-07-14T23:59:59.000Z
The present work investigates the turbulent jet flow mixing of downward impinging jets within a staggered rod bundle based on previous experimental work. The two inlet jets had Reynold's numbers of 11,160 and 6,250 and were chosen to coincide...
Probabilistic Power Flow Simulation allowing Temporary Current Overloading
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
Quantum Simulator for Transport Phenomena in Fluid Flows
A. Mezzacapo; M. Sanz; L. Lamata; I. L. Egusquiza; S. Succi; E. Solano
2015-08-19T23:59:59.000Z
Transport phenomena still stand as one of the most challenging problems in computational physics. By exploiting the analogies between Dirac and lattice Boltzmann equations, we develop a quantum simulator based on pseudospin-boson quantum systems, which is suitable for encoding fluid dynamics transport phenomena within a lattice kinetic formalism. It is shown that both the streaming and collision processes of lattice Boltzmann dynamics can be implemented with controlled quantum operations, using a heralded quantum protocol to encode non-unitary scattering processes. The proposed simulator is amenable to realization in controlled quantum platforms, such as ion-trap quantum computers or circuit quantum electrodynamics processors.
Dispersion of swimming algae in laminar and turbulent channel flows: theory and simulations
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...
Hull/Mooring/Riser coupled motion simulations of thruster-assisted moored platforms
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 ...
A Hybrid Multiscale Framework for Subsurface Flow and Transport Simulations
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Scheibe, Timothy D.; Yang, Xiaofan; Chen, Xingyuan; Hammond, Glenn E.
2015-06-01T23:59:59.000Z
Extensive research efforts have been invested in reducing model errors to improve the predictive ability of biogeochemical earth and environmental system simulators, with applications ranging from contaminant transport and remediation to impacts of biogeochemical elemental cycling (e.g., carbon and nitrogen) on local ecosystems and regional to global climate. While the bulk of this research has focused on improving model parameterizations in the face of observational limitations, the more challenging type of model error/uncertainty to identify and quantify is model structural error which arises from incorrect mathematical representations of (or failure to consider) important physical, chemical, or biological processes, properties, ormore »system states in model formulations. While improved process understanding can be achieved through scientific study, such understanding is usually developed at small scales. Process-based numerical models are typically designed for a particular characteristic length and time scale. For application-relevant scales, it is generally necessary to introduce approximations and empirical parameterizations to describe complex systems or processes. This single-scale approach has been the best available to date because of limited understanding of process coupling combined with practical limitations on system characterization and computation. While computational power is increasing significantly and our understanding of biological and environmental processes at fundamental scales is accelerating, using this information to advance our knowledge of the larger system behavior requires the development of multiscale simulators. Accordingly there has been much recent interest in novel multiscale methods in which microscale and macroscale models are explicitly coupled in a single hybrid multiscale simulation. A limited number of hybrid multiscale simulations have been developed for biogeochemical earth systems, but they mostly utilize application-specific and sometimes ad-hoc approaches for model coupling. We are developing a generalized approach to hierarchical model coupling designed for high-performance computational systems, based on the Swift computing workflow framework. In this presentation we will describe the generalized approach and provide two use cases: 1) simulation of a mixing-controlled biogeochemical reaction coupling pore- and continuum-scale models, and 2) simulation of biogeochemical impacts of groundwater – river water interactions coupling fine- and coarse-grid model representations. This generalized framework can be customized for use with any pair of linked models (microscale and macroscale) with minimal intrusiveness to the at-scale simulators. It combines a set of python scripts with the Swift workflow environment to execute a complex multiscale simulation utilizing an approach similar to the well-known Heterogeneous Multiscale Method. User customization is facilitated through user-provided input and output file templates and processing function scripts, and execution within a high-performance computing environment is handled by Swift, such that minimal to no user modification of at-scale codes is required.« less
Simulation of relativistically colliding laser-generated electron flows
Yang, Xiaohu; Sarri, Gianluca; Borghesi, Marco
2012-01-01T23:59:59.000Z
The plasma dynamics resulting from the simultaneous impact, of two equal, ultra-intense laser pulses, in two spatially separated spots, onto a dense target is studied via particle-in-cell (PIC) simulations. The simulations show that electrons accelerated to relativistic speeds, cross the target and exit at its rear surface. Most energetic electrons are bound to the rear surface by the ambipolar electric field and expand along it. Their current is closed by a return current in the target, and this current configuration generates strong surface magnetic fields. The two electron sheaths collide at the midplane between the laser impact points. The magnetic repulsion between the counter-streaming electron beams separates them along the surface normal direction, before they can thermalize through other beam instabilities. This magnetic repulsion is also the driving mechanism for the beam-Weibel (filamentation) instability, which is thought to be responsible for magnetic field growth close to the internal shocks of ...
A Hybrid Multiscale Framework for Subsurface Flow and Transport Simulations
Scheibe, Timothy D.; Yang, Xiaofan; Chen, Xingyuan; Hammond, Glenn E.
2015-01-01T23:59:59.000Z
Extensive research efforts have been invested in reducing model errors to improve the predictive ability of biogeochemical earth and environmental system simulators, with applications ranging from contaminant transport and remediation to impacts of biogeochemical elemental cycling (e.g., carbon and nitrogen) on local ecosystems and regional to global climate. While the bulk of this research has focused on improving model parameterizations in the face of observational limitations, the more challenging type of model error/uncertainty to identify and quantify is model structural error which arises from incorrect mathematical representations of (or failure to consider) important physical, chemical, or biological processes, properties, or system states in model formulations. While improved process understanding can be achieved through scientific study, such understanding is usually developed at small scales. Process-based numerical models are typically designed for a particular characteristic length and time scale. For application-relevant scales, it is generally necessary to introduce approximations and empirical parameterizations to describe complex systems or processes. This single-scale approach has been the best available to date because of limited understanding of process coupling combined with practical limitations on system characterization and computation. While computational power is increasing significantly and our understanding of biological and environmental processes at fundamental scales is accelerating, using this information to advance our knowledge of the larger system behavior requires the development of multiscale simulators. Accordingly there has been much recent interest in novel multiscale methods in which microscale and macroscale models are explicitly coupled in a single hybrid multiscale simulation. A limited number of hybrid multiscale simulations have been developed for biogeochemical earth systems, but they mostly utilize application-specific and sometimes ad-hoc approaches for model coupling. We are developing a generalized approach to hierarchical model coupling designed for high-performance computational systems, based on the Swift computing workflow framework. In this presentation we will describe the generalized approach and provide two use cases: 1) simulation of a mixing-controlled biogeochemical reaction coupling pore- and continuum-scale models, and 2) simulation of biogeochemical impacts of groundwater – river water interactions coupling fine- and coarse-grid model representations. This generalized framework can be customized for use with any pair of linked models (microscale and macroscale) with minimal intrusiveness to the at-scale simulators. It combines a set of python scripts with the Swift workflow environment to execute a complex multiscale simulation utilizing an approach similar to the well-known Heterogeneous Multiscale Method. User customization is facilitated through user-provided input and output file templates and processing function scripts, and execution within a high-performance computing environment is handled by Swift, such that minimal to no user modification of at-scale codes is required.
Hydrodynamical adaptive mesh refinement simulations of turbulent flows - I. Substructure in a wind
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.
Hydrodynamical adaptive mesh refinement simulations of turbulent flows - I. Substructure in a wind
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.
Simulation of FCC riser flow with multiphase heat transfer and cracking reactions.
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.
Sensitivity Analysis and Stochastic Simulations of Non-equilibrium Plasma Flow
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.
Simulation of heavy oil reservoir performance using a non-Newtonian flow model
Narahara, Gene Masao
1983-01-01T23:59:59.000Z
AAM University Chairman of Advisory Committee: Dr. Ching Wu Several published reports have concluded that certain crude oils, especially heavy oils, exhibit non-Newtonian flow characteristics. When these non-Newtonian oils are sub... Production, Kv/Kh 0. 1 - Viscosity Distribution of the Top Layer of the Non-Newtonian Oil Graphed with Respect to Time (Log Scale) 63 64 65 INTRODUCTION In simulating the flow of crude oils in porous media, oil has generally been assumed to be a...
Mesoscale flows in large aspect ratio simulations of turbulent compressible convection
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.
Numerical simulation of laminar reacting flows with complex chemistry
Day, Marcus S.; Bell, John B.
1999-12-01T23:59:59.000Z
We present an adaptive algorithm for low Mach number reacting flows with complex chemistry. Our approach uses a form of the low Mach number equations that discretely conserves both mass and energy. The discretization methodology is based on a robust projection formulation that accommodates large density contrasts. The algorithm uses an operator-split treatment of stiff reaction terms and includes effects of differential diffusion. The basic computational approach is embedded in an adaptive projection framework that uses structured hierarchical grids with subcycling in time that preserves the discrete conservation properties of the underlying single-grid algorithm. We present numerical examples illustrating the performance of the method on both premixed and non-premixed flames.
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
Free-surface flow simulations for discharge-based operation of hydraulic structure gates
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...
Closures for Course-Grid Simulation of Fluidized Gas-Particle Flows
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.
Stochastic Simulations and Sensitivity Analysis of Plasma Flow
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.
Walker, Lawrence R.
Injured? Workers' Compensation Flow Chart Please contact Risk Management and Safety if assistance is able. The C-1 form is sent/faxed to Risk Management and Safety as soon as possible. Supervisor to the appropriate Safety Office Employee completes the C-1 form. The C-1 form is sent/faxed to Risk Management
Peszynska, Malgorzata
Society of Petroleum Engineers SPE 51920 Staggered In Time Coupling of Reservoir Flow Simulation, The University of Texas at Austin Copyright 1999, Society of Petroleum Engineers, Inc. Thispaperwas by the Society of Petroleum Engineers and are subject to correction by the author(s). The material, as presented
An analysis of flow-simulation scales and seismic response P. L. Stoffa*
Bangerth, Wolfgang
computational costs and our ability to predict reservoir changes from seismic observations. A sensitivity study that the current reservoir characterization tools can generate very refined reservoir models containing millions resolution in flow and seismic simulations when the two processes are coupled in an iterative inversion
RESEARCH PAPER Simulation-based analysis of flow due to traveling-plane-wave
Yanikoglu, Berrin
RESEARCH PAPER Simulation-based analysis of flow due to traveling-plane-wave deformations: 28 March 2007 Ó Springer-Verlag 2007 Abstract One of the propulsion mechanisms of micro- organisms be placed in a channel and actuated for pumping of the fluid by means of introducing a series of traveling-wave
Flow Simulations of a Rotating MidSized Rim Driven Wind Turbine
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 relatively high free stream wind velocities that limit the geographic areas suitable for wind energy
Resistive MHD Simulations of Laminar Round Jets with Application to Magnetic Nozzle Flows
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...
Numerical simulation of flow distribution for pebble bed high temperature gas cooled reactors
Yesilyurt, Gokhan
2004-09-30T23:59:59.000Z
to study the flow past bluff bodies. A suitable CFD code (CFX5.6b) was selected and implemented. Simulation of turbulent transport for the gas through the gaps of the randomly distributed spherical fuel elements (pebbles) was performed. Although there are a...
Domain Decomposition Algorithm and Analytical Simulation of Coupled Flow in Reservoir / Well System
Ewing, Richard E.
that the technological progress of horizontal well drilling has been recognized by the petroleum industry as a most e of the wall and acceleration terms in balance equation. In the present paper a model of a reservoir/wellDomain Decomposition Algorithm and Analytical Simulation of Coupled Flow in Reservoir / Well System
Domain Decomposition Algorithm and Analytical Simulation of Coupled Flow in Reservoir / Well System
Lazarov, Raytcho
of horizontal well drilling has been recognized by the petroleum industry as a most efficient technique of the wall and acceleration terms in balance equation. In the present paper a model of a reservoir/wellDomain Decomposition Algorithm and Analytical Simulation of Coupled Flow in Reservoir / Well System
Straub, John E.
Simulating Vibrational Energy Flow in Proteins: Relaxation Rate and Mechanism for Heme Cooling 02215 ReceiVed: April 30, 2003; In Final Form: July 24, 2003 The rate and mechanism of the kinetic was found to proceed via a spatially anisotropic "funneling" mechanism as a single-exponential process
Towards Numerical Simulation of Cavitating Flows in Complex M. Mattson and K. Mahesh
Mahesh, Krishnan
Towards Numerical Simulation of Cavitating Flows in Complex Geometries M. Mattson and K. Mahesh (Aerospace Engineering and Mechanics, University of Minnesota) 27th Symposium on Naval Hydrodynamics Seoul of bubbles in complex geometries, with specific applica- tion to modeling cavitation instabilities
McKenzie, Jeffrey M.
Groundwater flow with energy transport and waterice phase change: Numerical simulations saturated, coupled porewater-energy transport, with freezing and melting porewater, and includes propor for groundwater and energy transport with ice formation and melting are proposed that may be used by other
Roma "La Sapienza", UniversitÃ di
2011-01-01T23:59:59.000Z
been found to play a key role in assisting the transport of energy and information in complex quantum transmission efficiency can be measured. Introducing dephasing in the photon path, this system exhibits a characteristic enhancement of the transport efficiency that can be observed with presently available technology
The Numerical Simulation Of A Transitional Flow In The VKI-GENOA Turbine Cascade
Yershov, Sergiy; Yakovlev, Viktor; Gryzun, Maria
2015-01-01T23:59:59.000Z
This study presents a numerical simulation of a 3D viscous flow in the VKI-Genoa cascade that takes into account the laminar-turbulent transition. The numerical simulation is performed using the Reynolds-averaged Navier-Stokes equations and the two-equation k-omega SST turbulence model. The algebraic Production Term Modification model is used for modeling the laminar-turbulent transition. Computations of both fully turbulent and transitional flows are carried out. The contours of the Mach number, the turbulence kinetic energy, the entropy function, as well as limiting streamlines are presented. The analysis of the numerical results demonstrates the influence of the laminar-turbulent transition on the secondary flow pattern. The comparison between the present computational results and the existing experimental and numerical data shows that the proposed approach reflects sufficiently the physics of the laminar-turbulent transition in turbine cascades.
Apparatus and method for interaction phenomena with world modules in data-flow-based simulation
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.
Guidoboni, Giovanna
2007-01-01T23:59:59.000Z
J. Non-Newtonian Fluid Mech. 142 (2007) 36Â62 Review On the numerical simulation of Bingham visco-plastic various results and methods concerning the numerical simulation of Bingham visco-plastic flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 2. On the modeling of Bingham viscous plastic flow
Adaptive and Efficient Computing for Subsurface Simulation within ParFlow
Tiedeman, H; Woodward, C S
2010-11-16T23:59:59.000Z
This project is concerned with the PF.WRF model as a means to enable more accurate predictions of wind fluctuations and subsurface storage. As developed at LLNL, PF.WRF couples a groundwater (subsurface) and surface water flow model (ParFlow) to a mesoscale atmospheric model (WRF, Weather Research and Forecasting Model). It was developed as a unique tool to address coupled water balance and wind energy questions that occur across traditionally separated research regimes of the atmosphere, land surface, and subsurface. PF.WRF is capable of simulating fluid, mass, and energy transport processes in groundwater, vadose zone, root zone, and land surface systems, including overland flow, and allows for the WRF model to both directly drive and respond to surface and subsurface hydrologic processes and conditions. The current PF.WRF model is constrained to have uniform spatial gridding below the land surface and matching areal grids with the WRF model at the land surface. There are often cases where it is advantageous for land surface, overland flow and subsurface models to have finer gridding than their atmospheric counterparts. Finer vertical discretization is also advantageous near the land surface (to properly capture feedbacks) yet many applications have a large vertical extent. However, the surface flow is strongly dependent on topography leading to a need for greater lateral resolution in some regions and the subsurface flow is tightly coupled to the atmospheric model near the surface leading to a need for finer vertical resolution. In addition, the interactions (e.g. rain) will be highly variable in space and time across the problem domain so an adaptive scheme is preferred to a static strategy to efficiently use computing and memory resources. As a result, this project focussed on algorithmic research required for development of an adaptive simulation capability in the PF.WRF system and its subsequent use in an application problem in the Central Valley of California. This report documents schemes of use for a future implementation of an adaptive grid capability within the ParFlow subsurface flow simulator in PF.WRF. The methods describe specific handling of the coarse/fine boundaries within a cell-centered discretization of the nonlinear parabolic Richards equation model for variable saturated flow. In addition, we describe development of a spline fit and table lookup method implemented within ParFlow to enhance computational efficiency of variably saturated flow calculations.
Multiscale Simulation of Blood Flow in Brain Arteries with an Aneurysm
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
Nature of turbulent transport across sheared zonal flows: insights from gyro-kinetic simulations
Sanchez, Raul [ORNL; Newman, David E [University of Alaska; Leboeuf, Jean-Noel [JNL Scientific, Inc., Casa Grande, AZ; Decyk, Viktor [University of California, Los Angeles
2011-01-01T23:59:59.000Z
The traditional view regarding the reduction of turbulence-induced transport across a stable sheared flow invokes a reduction of the characteristic length scale in the direction perpendicular to the flow as a result of the shearing and stretching of eddies caused by the differential pull exerted in the direction of the flow. A reduced effective transport coefficient then suffices to capture the reduction, that can then be readily incorporated into a transport model. However, recent evidence from gyrokinetic simulations of the toroidal ion-temperature-gradient mode suggests that the dynamics of turbulent transport across sheared flows changes in a more fundamental manner, and that the use of reduced effective transport coefficients fails to capture the full dynamics that may exhibit both subdiffusion and non-Gaussian statistics. In this contribution, after briefly reviewing these results, we propose some candidates for the physical mechanisms responsible for endowing transport with such non-diffusive characteristics, backing these proposals with new numerical gyrokinetic data
A hybrid stochastic-deconvolution model for large-eddy simulation of particle-laden flow
Micha?ek, W. R., E-mail: w.michalek@tue.nl [Department of Mechanical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Kuerten, J. G. M. [Department of Mechanical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands) [Department of Mechanical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Faculty EEMCS, University of Twente, 7500 AE Enschede (Netherlands); Zeegers, J. C. H.; Liew, R. [Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands)] [Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Pozorski, J. [Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Gdansk (Poland)] [Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Gdansk (Poland); Geurts, B. J. [Faculty EEMCS, University of Twente, 7500 AE Enschede (Netherlands) [Faculty EEMCS, University of Twente, 7500 AE Enschede (Netherlands); Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands)
2013-12-15T23:59:59.000Z
We develop a hybrid model for large-eddy simulation of particle-laden turbulent flow, which is a combination of the approximate deconvolution model for the resolved scales and a stochastic model for the sub-grid scales. The stochastic model incorporates a priori results of direct numerical simulation of turbulent channel flow, which showed that the parameters in the stochastic model are quite independent of Reynolds and Stokes number. In order to correctly predict the flux of particles towards the walls an extra term should be included in the stochastic model, which corresponds to the term related to the well-mixed condition in Langevin models for particle dispersion in inhomogeneous turbulent flow. The model predictions are compared with results of direct numerical simulation of channel flow at a frictional Reynolds number of 950. The inclusion of the stochastic forcing is shown to yield a significant improvement over the approximate deconvolution model for the particles alone when combined with a Stokes dependent weight-factor for the well-mixed term.
Simulation of coastal flow fields when the incident solar radiation is obscured
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.
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.
Computer assisted gamma and X-ray tomography: Applications to multiphase flow systems
Kumar, S.B.; Dudukovic, M.
1998-01-01T23:59:59.000Z
In process vessels, involving two or three phases it is often important not only to know the volume fraction (holdup) of each phase but also the spatial distribution of such holdups. This information is needed in control, trouble shooting and assessment of flow patterns and can be observed noninvasively by the application of Computed Tomography (CT). This report presents a complete overview of X-ray and gamma ray transmission tomography principles, equipment design to specific tasks and application in process industry. The fundamental principles of tomography, the algorithms for image reconstruction, the measurement method and the possible sources of error are discussed in detail. A case study highlights the methodology involved in designing a scanning system for the study of a given process unit, e.g., reactor, separations column etc. Results obtained in the authors` laboratory for the gas holdup distribution in bubble columns are also presented. Recommendations are made for the Advanced Fuels Development Unit (AFDU) in LaPorte, TX.
Electrodeposition of Au/Ag bimetallic dendrites assisted by Faradaic AC-electroosmosis flow
Ji, Jianlong; Li, Pengwei; Sang, Shengbo, E-mail: sbsang@tyut.edu.cn; Zhang, Wendong, E-mail: wdzhang@tyut.edu.cn; Li, Gang; Hu, Jie [Micro and Nano-system Research Centre, College of Information Engineering, Taiyuan University of Technology, 030024, Taiyuan (China)] [Micro and Nano-system Research Centre, College of Information Engineering, Taiyuan University of Technology, 030024, Taiyuan (China); Zhou, Zhaoying, E-mail: zhouzy@mail.tsinghua.edu.cn; Yang, Xing; Dong, Hualai [MEMS Laboratory, Department of Precision Instruments, Tsinghua University, 100084, Beijing (China)] [MEMS Laboratory, Department of Precision Instruments, Tsinghua University, 100084, Beijing (China)
2014-03-15T23:59:59.000Z
Au/Ag bimetallic dendrites were synthesized successfully from the corresponding aqueous solution via the AC electrodeposition method. Both of the morphologies and compositions could be tuned by the electrolyte concentration and AC frequency. The prepared bimetallic dendrites were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM) and UV–vis spectroscopy. The underlying dendrite growth mechanism was then proposed in the context of the Directed Electrochemical Nanowires Assembly (DENA) models. Owing to the unscreened voltage dropping in the electrolyte bulk, electromigration dominates the species flux process, and cations tend to accumulate in areas with strong electric field intensity, such as electrode edges. Moreover, Faradaic AC-electro-osmosis (ACEO) flow could increase the effective diffusion layer thickness in these areas during the electrochemical reaction, and leads to dendrite growth. Further Micro-Raman observations illustrated that the Au/Ag bimetallic dendrites exhibited pronounced surface-enhanced Raman scattering (SERS) activity, using 4-mercaptopyridine (4-MP) as model molecules.
TOUGH Simulations of the Updegraff's Set of Fluid and Heat Flow Problems
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.
Chen, Qingyan "Yan"
Fast and Informative Flow Simulations in a Building by Using Fast Fluid Dynamics Model on Graphics simulations are necessary for building emergency management, preliminary design of sustainable buildings for a whole building. This paper reports our efforts on further accelerating FFD simulation by running
Using Stochastic Discounted Cash Flow and Real Option Monte Carlo Simulation to Analyse the Impacts in the presence of a windfall profits tax. Real options Monte Carlo simulation is used to characterise from the project. The results highlight that Monte Carlo simulation paired with the real option
Large-eddy simulation of turbulent cavitating flow in a micro channel
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.
Coarse-grained simulations of vortex dynamics and transition in complex high-Re flows
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
Simulation of hydrogen and hydrogen-assisted propane ignition in Pt catalyzed microchannel
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)
Simulating the dissociation of CO/sub 2/ in a supersonic nonequilibrium plasma flow
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.
Pair interaction lattice gas simulations: Flow past obstacles in two and three dimensions
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.
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.
Numerical simulation of laminar plasma dynamos in a cylindrical von Karman flow
Khalzov, I. V.; Brown, B. P.; Schnack, D. D.; Forest, C. B. [University of Wisconsin, 1150 University Avenue, Madison, Wisconsin 53706 (United States); Ebrahimi, F. [University of New Hampshire, 8 College Road, Durham, New Hampshire 03824 (United States)
2011-03-15T23:59:59.000Z
The results of a numerical study of the magnetic dynamo effect in cylindrical von Karman plasma flow are presented with parameters relevant to the Madison Plasma Couette Experiment. This experiment is designed to investigate a broad class of phenomena in flowing plasmas. In a plasma, the magnetic Prandtl number Pm can be of order unity (i.e., the fluid Reynolds number Re is comparable to the magnetic Reynolds number Rm). This is in contrast to liquid metal experiments, where Pm is small (so, Re>>Rm) and the flows are always turbulent. We explore dynamo action through simulations using the extended magnetohydrodynamic NIMROD code for an isothermal and compressible plasma model. We also study two-fluid effects in simulations by including the Hall term in Ohm's law. We find that the counter-rotating von Karman flow results in sustained dynamo action and the self-generation of magnetic field when the magnetic Reynolds number exceeds a critical value. For the plasma parameters of the experiment, this field saturates at an amplitude corresponding to a new stable equilibrium (a laminar dynamo). We show that compressibility in the plasma results in an increase of the critical magnetic Reynolds number, while inclusion of the Hall term in Ohm's law changes the amplitude of the saturated dynamo field but not the critical value for the onset of dynamo action.
Numerical simulation of laminar plasma dynamos in a cylindrical von K\\'arm\\'an flow
Khalzov, I V; Ebrahimi, F; Schnack, D D; Forest, C B; 10.1063/1.3559472
2011-01-01T23:59:59.000Z
The results of a numerical study of the magnetic dynamo effect in cylindrical von K\\'arm\\'an plasma flow are presented with parameters relevant to the Madison Plasma Couette Experiment. This experiment is designed to investigate a broad class of phenomena in flowing plasmas. In a plasma, the magnetic Prandtl number Pm can be of order unity (i.e., the fluid Reynolds number Re is comparable to the magnetic Reynolds number Rm). This is in contrast to liquid metal experiments, where Pm is small (so, Re>>Rm) and the flows are always turbulent. We explore dynamo action through simulations using the extended magnetohydrodynamic NIMROD code for an isothermal and compressible plasma model.We also study two-fluid effects in simulations by including the Hall term in Ohm's law. We find that the counter-rotating von K\\'arm\\'an flow results in sustained dynamo action and the self-generation of magnetic field when the magnetic Reynolds number exceeds a critical value. For the plasma parameters of the experiment, this field ...
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
Comparison between RHD simulation of supercritical accretion flows and steady model with outflows
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...
Simulation of Coupled Processes of Flow, Transport, and Storage of CO2 in Saline Aquifers
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
All-optical cavity-based simulator of noise-assisted transport
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.
All-optical cavity-based simulator of noise-assisted transport
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.
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...
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
Simon, Hélène A.; Ge, Liang; Sotiropoulos, Fotis; Yoganathan, Ajit P.
2010-01-01T23:59:59.000Z
G. Rau. Leakage ?ow at mechanical heart valve prostheses:and the valve housing and forms two strong leakage jets onleakage ?ow rate Simulation of the Three-Dimensional Hinge Flow Fields through the closed valve
General Relativistic Hydrodynamic Simulation of Accretion Flow from a Stellar Tidal Disruption
Shiokawa, Hotaka; Cheng, Roseanne M; Piran, Tsvi; Noble, Scott C
2015-01-01T23:59:59.000Z
We study how the matter dispersed when a supermassive black hole tidally disrupts a star joins an accretion flow. Combining a relativistic hydrodynamic simulation of the stellar disruption with a relativistic hydrodynamics simulation of the tidal debris motion, we track such a system until ~80% of the stellar mass bound to the black hole has settled into an accretion flow. Shocks near the stellar pericenter and also near the apocenter of the most tightly-bound debris dissipate orbital energy, but only enough to make the characteristic radius comparable to the semi-major axis of the most-bound material, not the tidal radius as previously thought. The outer shocks are caused by post-Newtonian effects, both on the stellar orbit during its disruption and on the tidal forces. Accumulation of mass into the accretion flow is non-monotonic and slow, requiring ~3--10x the orbital period of the most tightly-bound tidal streams, while the inflow time for most of the mass may be comparable to or longer than the mass accu...
Numerical simulation of coastal flows when solar radiation is blocked by smoke
Molenkamp, C. R.
1989-05-01T23:59:59.000Z
Smoke from fires ignited in a large-scale nuclear exchange would greatly reduce the flux of solar radiation at the ground and lead to rapid cooling over continental regions. Because of its large heat capacity, the ocean would cool more slowly so that a thermal gradient would tend to develop at the continental coastlines. In order to investigate the hypothesis that these thermal gradients would lead to zones of persistent precipitation along the coastlines, a modified version of the Colorado State University Mesoscale Model has been used to simulate the evolution of atmospheric flows for both West and East coasts assuming a moderate westerly synoptic flow of 5 m s/sup /minus/1/. In both cases a layer of fog forms over the ground, effectively limiting the rate of cooling over land. This fog layer grows in height as the atmosphere aloft cools, forming a stratus cloud. Moisture from the ocean surface, mixed vertically into a radiatively cooled atmosphere, causes a cloud layer to form over the ocean as well. With both land and sea covered by clouds, there is no differential cooling, anomalous flow fields, or enhanced precipitation. These simulations also demonstrate the important role of moisture in moderating the initial rate of atmospheric cooling when solar radiation is blocked by smoke.
Triadic resonances in non-linear simulations of a fluid flow in a precessing cylinder
Giesecke, A; Gundrum, T; Herault, J; Stefani, F
2015-01-01T23:59:59.000Z
We present results from three-dimensional non-linear hydrodynamic simulations of a precession driven flow in cylindrical geometry. The simulations are motivated by a dynamo experiment currently under development at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) in which the possibility of generating a magnetohydrodynamic dynamo will be investigated in a cylinder filled with liquid sodium and simultaneously rotating around two axes. In this study, we focus on the emergence of non-axisymmetric time-dependent flow structures in terms of inertial waves which - in cylindrical geometry - form so-called Kelvin modes. For a precession ratio ${\\rm{Po}}=\\Omega_p/\\Omega_c=0.014$ the amplitude of the forced Kelvin mode reaches up to one fourth of the rotation velocity of the cylindrical container confirming that precession provides a rather efficient flow driving mechanism even at moderate values of ${\\rm{Po}}$. More relevant for dynamo action might be free Kelvin modes with higher azimuthal wave number. These free Kelvin m...
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Lykov, Kirill; Li, Xuejin; Lei, Huan; Pivkin, Igor V.; Karniadakis, George Em; Feng, James
2015-08-28T23:59:59.000Z
When blood flows through a bifurcation, red blood cells (RBCs) travel into side branches at different hematocrit levels, and it is even possible that all RBCs enter into one branch only, leading to a complete separation of plasma and RBCs. To quantify this phenomenon via particle-based mesoscopic simulations, we developed a general framework for open boundary conditions in multiphase flows that is effective even for high hematocrit levels. The inflow at the inlet is duplicated from a fully developed flow generated in a pilot simulation with periodic boundary conditions. The outflow is controlled by adaptive forces to maintain the flowmore »rate and velocity gradient at fixed values, while the particles leaving the arteriole at the outlet are removed from the system. Upon validation of this approach, we performed systematic 3D simulations to study plasma skimming in arterioles of diameters 20 to 32 microns. For a flow rate ratio 6:1 at the branches, we observed the “all-or-nothing” phenomenon with plasma only entering the low flow rate branch. We then simulated blood-plasma separation in arteriolar bifurcations with different bifurcation angles and same diameter of the daughter branches. Our simulations predict a significant increase in RBC flux through the main daughter branch as the bifurcation angle is increased. Finally, we demonstrated the effectiveness of the new methodology in simulations of blood flow in vessels with multiple inlets and outlets, constructed using an angiogenesis mode« less
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
Two-dimensional PIC simulations of ion-beam instabilities in Supernova-driven plasma flows
M. E. Dieckmann; A. Meli; P. K. Shukla; L. O. C. Drury; A. Mastichiadis
2008-04-16T23:59:59.000Z
Supernova remnant (SNR) blast shells can reach the flow speed $v_s = 0.1 c$ and shocks form at its front. Instabilities driven by shock-reflected ion beams heat the plasma in the foreshock, which may inject particles into diffusive acceleration. The ion beams can have the speed $v_b \\approx v_s$. For $v_b \\ll v_s$ the Buneman or upper-hybrid instabilities dominate, while for $v_b \\gg v_s$ the filamentation and mixed modes grow faster. Here the relevant waves for $v_b \\approx v_s$ are examined and how they interact nonlinearly with the particles. The collision of two plasma clouds at the speed $v_s$ is modelled with particle-in-cell (PIC) simulations, which convect with them magnetic fields oriented perpendicular to their flow velocity vector. One simulation models equally dense clouds and the other one uses a density ratio of 2. Both simulations show upper-hybrid waves that are planar over large spatial intervals and that accelerate electrons to $\\sim$ 10 keV. The symmetric collision yields only short oscillatory wave pulses, while the asymmetric collision also produces large-scale electric fields, probably through a magnetic pressure gradient. The large-scale fields destroy the electron phase space holes and they accelerate the ions, which facilitates the formation of a precursor shock.
Large-eddy simulations of turbulent flow for grid-to-rod fretting in nuclear reactors
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...
DENSE MULTIPHASE FLOW SIMULATION: CONTINUUM MODEL FOR POLY-DISPERSED SYSTEMS USING KINETIC THEORY
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.
Kim, Jihoon; Moridis, George
2013-05-22T23:59:59.000Z
We developed a hydraulic fracturing simulator by coupling a flow simulator to a geomechanics code, namely T+M simulator. Modeling of the vertical fracture development involves continuous updating of the boundary conditions and of the data connectivity, based on the finite element method for geomechanics. The T+M simulator can model the initial fracture development during the hydraulic fracturing operations, after which the domain description changes from single continuum to double or multiple continua in order to rigorously model both flow and geomechanics for fracture-rock matrix systems. The T+H simulator provides two-way coupling between fluid-heat flow and geomechanics, accounting for thermoporomechanics, treats nonlinear permeability and geomechanical moduli explicitly, and dynamically tracks changes in the fracture(s) and in the pore volume. We also fully accounts for leak-off in all directions during hydraulic fracturing. We first validate the T+M simulator, matching numerical solutions with the analytical solutions for poromechanical effects, static fractures, and fracture propagations. Then, from numerical simulation of various cases of the planar fracture propagation, shear failure can limit the vertical fracture propagation of tensile failure, because of leak-off into the reservoirs. Slow injection causes more leak-off, compared with fast injection, when the same amount of fluid is injected. Changes in initial total stress and contributions of shear effective stress to tensile failure can also affect formation of the fractured areas, and the geomechanical responses are still well-posed.
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.
TOUGH2: A general-purpose numerical simulator for multiphase nonisothermal flows
Pruess, K. [Lawrence Berkeley Lab., CA (United States)
1991-06-01T23:59:59.000Z
Numerical simulators for multiphase fluid and heat flows in permeable media have been under development at Lawrence Berkeley Laboratory for more than 10 yr. Real geofluids contain noncondensible gases and dissolved solids in addition to water, and the desire to model such `compositional` systems led to the development of a flexible multicomponent, multiphase simulation architecture known as MULKOM. The design of MULKOM was based on the recognition that the mass-and energy-balance equations for multiphase fluid and heat flows in multicomponent systems have the same mathematical form, regardless of the number and nature of fluid components and phases present. Application of MULKOM to different fluid mixtures, such as water and air, or water, oil, and gas, is possible by means of appropriate `equation-of-state` (EOS) modules, which provide all thermophysical and transport parameters of the fluid mixture and the permeable medium as a function of a suitable set of primary thermodynamic variables. Investigations of thermal and hydrologic effects from emplacement of heat-generating nuclear wastes into partially water-saturated formations prompted the development and release of a specialized version of MULKOM for nonisothermal flow of water and air, named TOUGH. TOUGH is an acronym for `transport of unsaturated groundwater and heat` and is also an allusion to the tuff formations at Yucca Mountain, Nevada. The TOUGH2 code is intended to supersede TOUGH. It offers all the capabilities of TOUGH and includes a considerably more general subset of MULKOM modules with added capabilities. The paper briefly describes the simulation methodology and user features.
General Relativistic Hydrodynamic Simulation of Accretion Flow from a Stellar Tidal Disruption
Hotaka Shiokawa; Julian H. Krolik; Roseanne M. Cheng; Tsvi Piran; Scott C. Noble
2015-01-18T23:59:59.000Z
We study how the matter dispersed when a supermassive black hole tidally disrupts a star joins an accretion flow. Combining a relativistic hydrodynamic simulation of the stellar disruption with a relativistic hydrodynamics simulation of the tidal debris motion, we track such a system until ~80% of the stellar mass bound to the black hole has settled into an accretion flow. Shocks near the stellar pericenter and also near the apocenter of the most tightly-bound debris dissipate orbital energy, but only enough to make the characteristic radius comparable to the semi-major axis of the most-bound material, not the tidal radius as previously thought. The outer shocks are caused by post-Newtonian effects, both on the stellar orbit during its disruption and on the tidal forces. Accumulation of mass into the accretion flow is non-monotonic and slow, requiring ~3--10x the orbital period of the most tightly-bound tidal streams, while the inflow time for most of the mass may be comparable to or longer than the mass accumulation time. Deflection by shocks does, however, remove enough angular momentum and energy from some mass for it to move inward even before most of the mass is accumulated into the accretion flow. Although the accretion rate rises sharply and then decays roughly as a power-law, its maximum is ~0.1x the previous expectation, and the duration of the peak is ~5x longer than previously predicted. The geometric mean of the black hole mass and stellar mass inferred from a measured event timescale is therefore ~0.2x the value given by classical theory.
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.
Prediction of effects of hydraulic fracturing using reservoir and well flow simulation
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.
Turbulent flow over a house in a simulated hurricane boundary layer
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...
A Molecular Dynamics Simulation of the Turbulent Couette Minimal Flow Unit
Smith, E R
2015-01-01T23:59:59.000Z
A molecular dynamics (MD) simulation of planar Couette flow is presented for the minimal channel in which turbulence structures can be sustained. Evolution over a single breakdown and regeneration cycle is compared to computational fluid dynamics (CFD) simulations. Qualitative similar structures are observed and turbulent statistics show excellent quantitative agreement. The molecular scale law of the wall is presented in which stick-slip molecular wall-fluid interactions replace the no-slip conditions. The impact of grid resolution is explored and the observed structures are seen to be dependant on averaging time and length scales. The kinetic energy spectra show a range of scales are present in the molecular system and that spectral content is dependent on the grid resolution employed. The subgrid velocity of the molecules is compared to spatial averaged velocity using joint probability density functions. Molecular trajectories, diffusions and Lagrangian statistics are presented. The importance of sub-grid ...
Energy Simulation of Integrated Multiple-Zone Variable Refrigerant Flow System
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.
Modeling and Simulation of Two-Phase Two-Component Flow with Disappearing Nonwetting Phase
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...
CFD Simulation of 3D Flow field in a Gas Centrifuge
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)
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
Jameson, Antony
High-order accurate simulation of low-Mach laminar flow past two side-by-side cylinders using applications on simulating laminar flow past two side-by-side cylinders at various spacings. The high-by-side cylinders Investigations of the fluid flow and vortex dynamics about sim- ple configurations of two
Some Specific CASL Requirements for Advanced Multiphase Flow Simulation of Light Water Reactors
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).
Garain, Sudip K; Chakrabarti, Sandip K
2013-01-01T23:59:59.000Z
Low and intermediate frequency quasi-periodic oscillations (QPOs) in black hole candidates are believed to be due to oscillations of the Comptonizing regions in an accretion flow. Assuming that the general structure of an accretion disk is a Two Component Advective Flow (TCAF), we numerically simulate the light curves emitted from an accretion disk for different accretion rates and find how the QPO frequencies vary. We use a standard Keplerian disk residing at the equatorial plane as a source of soft photons. These soft photons, after suffering multiple scattering with the hot electrons of the low angular momentum, sub-Keplerian, flow emerge out as hard radiation. The hydrodynamic and thermal properties of the electron cloud is simulated using a Total Variation Diminishing (TVD) code. The TVD code is then coupled with a radiative transfer code which simulates the energy exchange between the electron and radiation using Monte Carlo technique. The resulting localized heating and cooling are included also. We fi...
A Many-Task Parallel Approach for Multiscale Simulations of Subsurface Flow and Reactive Transport
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.
Nikoleris, Teo
1988-01-01T23:59:59.000Z
NUMERICAL SIMULATION OF THE NON-ISOTHERMAL DEVELOPING FLOXV OF A NONLINEAR VISCOELASTIC FLUID IN A RECTANGULAR CHANNEL A Thesis by TEO NIKOLERIS Submitted to the Graduate College of Texas A&M University in partial fulfillment... developing flow of a nonlinear viscoelas- tic fluid. The temperature dependence of the rheological parameters was imposed using an Arrhenius-like exponential relationship. The flow was creeping, at the early stages of thermal development and wall cooling...
Garain, Sudip K; Chakrabarti, Sandip K
2013-01-01T23:59:59.000Z
We study the spectral and timing properties of a two component advective flow (TCAF) around a black hole by numerical simulation. Several cases have been simulated by varying the Keplerian disk rate and the resulting spectra and lightcurves have been produced for all the cases. The dependence of the spectral states and quasi-periodic oscillation (QPO) frequencies on the flow parameters is discussed. We also find the earlier explanation of arising of QPOs as the resonance between infall time scale and cooling time scale remain valid even for Compton cooling.
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.
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.
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...
Zhou, Y.; Wu, J.; Wang, R.; Shiochi, S.
2006-01-01T23:59:59.000Z
As a high-efficiency air conditioning scheme, the variable refrigerant flow (VRF) air-conditioning system is finding its way into medium-sized office buildings. Based on a generic dynamic building energy simulation environment, EnergyPlus, a new...
Texas at Arlington, University of
supersonic Mach numbers (2) A pulsed normal detonation wave mode at combustion chamber Mach numbers less thanCold Flow Simulations for a Pulse Detonation Rocket Ejector J. Tyler Nichols, Donald R. Wilson pulse detonation rocket (PDR) ejecting into a duct was fabricated and integrated into the supersonic
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...
Development and Validation of a Parallel MHD Code for the Simulation of Self-Field MPDT Flows
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
Reduced-Order Models of Zero-Net Mass-Flux Jets for Large-Scale Flow Control Simulations
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
Zhou, Y.; Wu, J.; Wang, R.; Shiochi, S.
2006-01-01T23:59:59.000Z
As a high-efficiency air conditioning scheme, the variable refrigerant flow (VRF) air-conditioning system is finding its way into medium-sized office buildings. Based on a generic dynamic building energy simulation environment, EnergyPlus, a new...
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.
Smyth, Tamara
is similar to that of a leaky valve where the leakage decreases as the volume flow decreases. 1. INTRODUCTIONDISCRETE-TIME SIMULATION OF AIR-FLOW CUT-OFF IN PRESSURE-CONTROLLED VALVES Tamara Smyth, Jonathan of the differential equation govern- ing volume flow through a pressure-controlled valve is examined with particular
Fully Nonlinear Edge Gyrokinetic Simulations of Kinetic Geodesic-Acoustic Modes and Boundary Flows
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.
A Convective-like Energy-Stable Open Boundary Condition for Simulations of Incompressible Flows
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...
Two-Dimensional Optical Measurement of Waves on Liquid Lithium Jet Simulating IFMIF Target Flow
Kazuhiro Itoh; Hiroyuki Koterazawa [University of Hyogo, 1-3-3, Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo (Japan); Taro Itoh; Yutaka Kukita [Nagoya University, Furo-cho, Chikusa-ku, Nagoya-shi, Aichi, 464-8603 (Japan); Hiroo Kondo; Nobuo Yamaoka; Hiroshi Horiike [Osaka University, 1-8 Yamadaoka, Suita, Osaka 565-0871 (Japan); Mizuho Ida; Hideo Nakamura; Hiroo Nakamura [Japan Atomic Energy Agency (Japan); Takeo Muroga [National Institute for Fusion Science, 322-6, Oroshi-cho, Toki, GIFU, 509-5292 (Japan)
2006-07-01T23:59:59.000Z
Waves on a liquid-lithium jet flow, simulating a proposed high-energy beam target design, have been measured using an optical technique based on specular reflection of a single laser beam on the jet surface. The stream-wise and spanwise fluctuations of the local free-surface slope were least-square fitted with a sinusoidal curve to makeup the signals lost due to the constriction in the optical arrangement. The waveform was estimated with an assumption that wave phase speed can be calculated using the dispersion relation for linear capillary-gravity waves. The direction of propagation on the jet surface was also evaluated so that the wave amplitudes, calculated by integral of slope angle signal, agree consistently in stream-wise and spanwise direction. These measurements and analyses show that the waves at the measurement location for a jet velocity of 1.2 m/s can best be represented by oblique waves with an inclination of 1.23 rad, a wavelength of 3.8 mm and a wave amplitude of about 0.05 mm. (authors)
Accelerating moderately stiff chemical kinetics in reactive-flow simulations using GPUs
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...
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 ...
Alfred, Dicman
2004-09-30T23:59:59.000Z
constant width. However, the flow characteristics of an actual fracture surface are quite different, affected by tortuosity and the impact of surface roughness. Though several researchers have discussed the effect of friction on flow reduction...
Theoretical and Numerical Simulation of Non-Newtonian Fluid Flow in Propped Fractures
Ouyang, Liangchen
2013-12-10T23:59:59.000Z
behavior in hydraulic fracturing theoretically and experimentally. I developed a model to describe the flow behavior of residual polymer gel being displaced by gas in parallel plates. I developed analytical models for gas-liquid two-phase stratified flow...
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
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.
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.
Large Eddy Simulation Analysis of Flow Field Inside a High-g Combustor
Raman, Venkat
-based combustion systems. Simulation results show that mixing of fuel and oxidizer is based on a jet-in-crossflow the jet and the crossflow determine fuel penetration, and will determine combustion e ciency. Simulation
................................................................................................................................................... 2 Reservoir Model ............................................................................................................................................. 7 Uncertainty Analysis........................................................................................................................................... 8 Tables Table 1. Reservoir and fluid properties used in the reservoir simulation model
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...
Large-Eddy Simulation of the Bachalo-Johnson Flow, with Shock...
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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,...
A Flux-Limited Numerical Method for the MHD Equations to Simulate Propulsive Plasma Flows
Choueiri, Edgar
to be effective tools in plasma propulsion research, a higher order accu- rate solver that captures MHD shocks approach, numerical simulations are valuable tools in plasma thruster research. More- over, simulations can Simula- tions The importance of numerical simulation in advancing plasma thruster research was realized
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.
Simulating surface and subsurface initiation of macropore flow Markus Weilera,*, Felix Naefb,1
Weiler, Markus
soil sections extracted from each study profile. The MDA was calculated for different sets of surface infiltration in macroporous soils. q 2003 Elsevier Science B.V. All rights reserved. Keywords: Macropore flow; Micro-topography; Preferential flow; Earthworm burrows; Infiltration 1. Introduction Macropores
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
Numerical simulation of flow of shear-thinning fluids in corrugated channels
Aiyalur Shankaran, Rohit
2009-05-15T23:59:59.000Z
A numerical study of flow of a shear thinning fluid through a pair of corrugated plates was carried out. The aim of the study was to observe and understand the behavior of the flow of shear thinning fluids through channels were the fluid...
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...
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.
NUMERICAL SIMULATIONS OF AIR FLOW AND HEAT TRANSFER VIA PDES By Fei Cao, Luz Angelica Caudillo Transfer via PDEs Fei Cao, Luz Angelica Caudillo-Mata, Natalia Iwanski, Yong Li, Kamran Sadiq, Arturo
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)
Yerramreddy, Anilkumar
1993-01-01T23:59:59.000Z
. 005) (f 4, 0, 200, + 0. 01 5) Fig. 3. Network Model for the Convex Cost Function The concave cost function cannot be modeled as a minimum cost linear network because the slope of the curve increases with each segment unlike in convex cost function.... 3. It uses no external node flow parameters. All such ini'ormation is described by arc parameters. 4. The algorithm may initiate with any set of flows that satisfies conservation of flow. 22 (Thus this algorithm &s particularly useful...
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
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 ...
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...
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...
Numerical simulation of flow and heat transfer of internal cooling passage in gas turbine blade
Su, Guoguang
2007-04-25T23:59:59.000Z
A computational study of three-dimensional turbulent flow and heat transfer was performed in four types of rotating channels. The first type is a rotating rectangular channel with V-shaped ribs. The channel aspect ratio ...
Modeling, Analysis and Simulation of Multiscale Preferential Flow - 8/05-8/10 - Final Report
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.
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 &...
PROBABILISTIC SIMULATION OF SUBSURFACE FLUID FLOW: A STUDY USING A NUMERICAL SCHEME
Buscheck, Timothy Eric
1980-03-01T23:59:59.000Z
There has been an increasing interest in probabilistic modeling of hydrogeologic systems. The classical approach to groundwater modeling has been deterministic in nature, where individual layers and formations are assumed to be uniformly homogeneous. Even in the case of complex heterogeneous systems, the heterogeneities describe the differences in parameter values between various layers, but not within any individual layer. In a deterministic model a single-number is assigned to each hydrogeologic parameter, given a particular scale of interest. However, physically there is no such entity as a truly uniform and homogeneous unit. Single-number representations or deterministic predictions are subject to uncertainties. The approach used in this work models such uncertainties with probabilistic parameters. The resulting statistical distributions of output variables are analyzed. A numerical algorithm, based on axiomatic principles of probability theory, performs arithmetic operations between probability distributions. Two subroutines are developed from the algorithm and incorporated into the computer program TERZAGI, which solves groundwater flow problems in saturated, multi-dimensional systems. The probabilistic computer program is given the name, PROGRES. The algorithm has been applied to study the following problems: one-dimensional flow through homogeneous media, steady-state and transient flow conditions, one-dimensional flow through heterogeneous media, steady-state and transient flow conditions, and two-dimensional steady-stte flow through heterogeneous media. The results are compared with those available in the literature.
PANS method of turbulence: simulation of high and low Reynolds number flows past a circular cylinder
Lakshmipathy, Sunil
2006-04-12T23:59:59.000Z
cylinder are performed at ReD 140,000 and ReD 3900 using the PANS model. The high Reynolds number PANS results are compared with experimental results from Cantwell and Coles, Large Eddy Simulation results from Breuer, and Detached Eddy Simulation results...
The matching of 3D Rolie-Poly viscoelastic numerical simulations with experimental polymer melt flow
Jimack, Peter
Kingdom J. Embery and D. Auhl IRC in Polymer Science and Technology, Department of Physics and AstronomyThe matching of 3D Rolie-Poly viscoelastic numerical simulations with experimental polymer melt of commercial viscoelastic polymer melts. Numerical simulation techniques have steadily advanced over the last
Two-Phase Flow Simulations In a Natural Rock Fracture using the VOF Method
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.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Schilling, Oleg; Mueschke, Nicholas J.
2010-10-18T23:59:59.000Z
Data from a 1152X760X1280 direct numerical simulation (DNS) of a transitional Rayleigh-Taylor mixing layer modeled after a small Atwood number water channel experiment is used to comprehensively investigate the structure of mean and turbulent transport and mixing. The simulation had physical parameters and initial conditions approximating those in the experiment. The budgets of the mean vertical momentum, heavy-fluid mass fraction, turbulent kinetic energy, turbulent kinetic energy dissipation rate, heavy-fluid mass fraction variance, and heavy-fluid mass fraction variance dissipation rate equations are constructed using Reynolds averaging applied to the DNS data. The relative importance of mean and turbulent production, turbulent dissipationmore »and destruction, and turbulent transport are investigated as a function of Reynolds number and across the mixing layer to provide insight into the flow dynamics not presently available from experiments. The analysis of the budgets supports the assumption for small Atwood number, Rayleigh/Taylor driven flows that the principal transport mechanisms are buoyancy production, turbulent production, turbulent dissipation, and turbulent diffusion (shear and mean field production are negligible). As the Reynolds number increases, the turbulent production in the turbulent kinetic energy dissipation rate equation becomes the dominant production term, while the buoyancy production plateaus. Distinctions between momentum and scalar transport are also noted, where the turbulent kinetic energy and its dissipation rate both grow in time and are peaked near the center plane of the mixing layer, while the heavy-fluid mass fraction variance and its dissipation rate initially grow and then begin to decrease as mixing progresses and reduces density fluctuations. All terms in the transport equations generally grow or decay, with no qualitative change in their profile, except for the pressure flux contribution to the total turbulent kinetic energy flux, which changes sign early in time (a countergradient effect). The production-to-dissipation ratios corresponding to the turbulent kinetic energy and heavy-fluid mass fraction variance are large and vary strongly at small evolution times, decrease with time, and nearly asymptote as the flow enters a self-similar regime. The late-time turbulent kinetic energy production-to-dissipation ratio is larger than observed in shear-driven turbulent flows. The order of magnitude estimates of the terms in the transport equations are shown to be consistent with the DNS at late-time, and also confirms both the dominant terms and their evolutionary behavior. These results are useful for identifying the dynamically important terms requiring closure, and assessing the accuracy of the predictions of Reynolds-averaged Navier-Stokes and large-eddy simulation models of turbulent transport and mixing in transitional Rayleigh-Taylor instability-generated flow.« less
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Schilling, Oleg [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Mueschke, Nicholas J. [Texas A and M Univ., College Station, TX (United States)
2010-01-01T23:59:59.000Z
Data from a 1152X760X1280 direct numerical simulation (DNS) of a transitional Rayleigh-Taylor mixing layer modeled after a small Atwood number water channel experiment is used to comprehensively investigate the structure of mean and turbulent transport and mixing. The simulation had physical parameters and initial conditions approximating those in the experiment. The budgets of the mean vertical momentum, heavy-fluid mass fraction, turbulent kinetic energy, turbulent kinetic energy dissipation rate, heavy-fluid mass fraction variance, and heavy-fluid mass fraction variance dissipation rate equations are constructed using Reynolds averaging applied to the DNS data. The relative importance of mean and turbulent production, turbulent dissipation and destruction, and turbulent transport are investigated as a function of Reynolds number and across the mixing layer to provide insight into the flow dynamics not presently available from experiments. The analysis of the budgets supports the assumption for small Atwood number, Rayleigh/Taylor driven flows that the principal transport mechanisms are buoyancy production, turbulent production, turbulent dissipation, and turbulent diffusion (shear and mean field production are negligible). As the Reynolds number increases, the turbulent production in the turbulent kinetic energy dissipation rate equation becomes the dominant production term, while the buoyancy production plateaus. Distinctions between momentum and scalar transport are also noted, where the turbulent kinetic energy and its dissipation rate both grow in time and are peaked near the center plane of the mixing layer, while the heavy-fluid mass fraction variance and its dissipation rate initially grow and then begin to decrease as mixing progresses and reduces density fluctuations. All terms in the transport equations generally grow or decay, with no qualitative change in their profile, except for the pressure flux contribution to the total turbulent kinetic energy flux, which changes sign early in time (a countergradient effect). The production-to-dissipation ratios corresponding to the turbulent kinetic energy and heavy-fluid mass fraction variance are large and vary strongly at small evolution times, decrease with time, and nearly asymptote as the flow enters a self-similar regime. The late-time turbulent kinetic energy production-to-dissipation ratio is larger than observed in shear-driven turbulent flows. The order of magnitude estimates of the terms in the transport equations are shown to be consistent with the DNS at late-time, and also confirms both the dominant terms and their evolutionary behavior. These results are useful for identifying the dynamically important terms requiring closure, and assessing the accuracy of the predictions of Reynolds-averaged Navier-Stokes and large-eddy simulation models of turbulent transport and mixing in transitional Rayleigh-Taylor instability-generated flow.
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.
Large-Eddy Simulation of Swirling Turbulent Jet Flows in Absence of Vortex Breakdown
Heinz, Stefan
simulation method to studies of the mechanism of swirl effects shows the following. Swirl breaks apart, n i 2 N0; 1 = kinematic viscosity T = Reynolds-averaged NavierStokes turbulent viscosity
Multiscale simulation of blood flow in brain arteries with an aneurysm
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).
Simulation of the quality of irrigation return flow from rice fields
Gerst, Michael Dean
1982-01-01T23:59:59.000Z
salt balance. The model predicted an emphasis on precipitation to supplement irrigation for managing irrigation water to reduce salt input, salt losses, and salt loading of the soil. Low simulated cation exchange capacities (CEC) resulted in high... predicted sales in the run-off and drainage waters. High simulated soil CEC resulted in low predicted salts in the runoff and drainage waters. The effect of fertilizer was shown to increase the cation concen- tration in the floodwater and to increase...
Curved plate damper test and simulations with snubbers, through- flow, and flexible plate effects
Gadangi, Ravindra Kumar
1992-01-01T23:59:59.000Z
through- flow, implying that tbe exit orifice is closed during the dynamic excitation of the damper plate. The energy is dissipated by the viscous shear of the fluid and orifice pressure drop. Damping coefficient is estimated by using a least...) . 3. 2 Comparison of results (concentrated load at the center) 3. 3 Comparison of results(fluid element model) 3. 4 Comparison oi' flows 4. 1 EfFects of variation of inlet orifice diameter 4. 2 EfFects of variation of damper clearance 4. 3 Ef...
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.
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.
Hartmann, Ralf
Flows, Error Estimation, Mesh Adaptation PACS: 02.60, 47.27, 47.11.Fg, 47.85.Gj 1. Introduction adaptation and efficient parallelization on modern distributed-memory computer architectures. While first of the European ADIGMA project [3], a coordinated European effort in advancing higher-order dis- cretization
Measurement and simulation of a droplet population in a turbulent flow field Rbert Bords a,1
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
Olshanskii, Maxim A.
and accurate numerical methods for computing flows with free surfaces and interfaces, see, e.g., [1, 2 is studied in a series of numerical experiments. Institute of Numerical Mathematics, Russian Academy@math.uh.edu Department of Energy Resources Engineering, Stanford University and Institute of Numerical Mathematics
Turbulence prediction in two- and three-dimensional bundle flows using Large Eddy Simulation
Ibrahim, Wael Abdul-Hamid
1994-01-01T23:59:59.000Z
of velocity fluctuations, small but macroscopic 'lumps' of fluid (eddies) are thrown about in the flow. Because these lumps carry mass, momentum, and energy, this enhanced mixing can lead to serious problems, such as in the increase of pressure drop in pipe...
Resistive MHD Simulations of Laminar Round Jets with Application to Magnetic Nozzle Flows
Araya, Daniel
2012-02-14T23:59:59.000Z
this large-scale device can fully function only in a vacuum. This difficulty makes computational analysis and modeling an important part of the design and testing process. A parallelized Boltzmann-BGK continuum flow solver is expanded to include resistive MHD...
COHERENT VORTEX SIMULATION (CVS) OF A FLOW PAST A NACA AIRFOIL 23012 AT RE = 1000
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
Rasmy Marsis, Emanuel 1983-
2012-08-16T23:59:59.000Z
to test the pump at different operating conditions. The pump is modeled and tested at two speeds; 3300 and 3600 rpm, using air-water mixtures with GVFs of 0, 5, 10, 25, 32 and 35%. The flow loop is controlled to produce different suction pressures up...
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
Multiphase flow and Encapsulation simulations using the moment of fluid method 1
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
Evaluating Subgrid-Scale Models for Large-Eddy Simulation of Turbulent Katabatic Flow
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
Accounting for finite-size effects in simulations of disperse particle-laden flows
Apte, Sourabh V.
, fluidized bed combustion, aerosol transport, and bubbly flows) involve millions of dispersed particles settling, (b) fluidization by a gaseous jet, and (c) fluidization by lift in a channel. The finite, and densities in the form of droplets, solid particles, or bubbles are dis- persed in a continuum (gaseous
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
Theoretical and Numerical Simulation of Non-Newtonian Fluid Flow in Propped Fractures
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...
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.
Miura, H; Miura, Hitoshi; Nakamoto, Taishi
2006-01-01T23:59:59.000Z
Millimeter-sized, spherical silicate grains abundant in chondritic meteorites, which are called as chondrules, are considered to be a strong evidence of the melting event of the dust particles in the protoplanetary disk. One of the most plausible scenarios is that the chondrule precursor dust particles are heated and melt in the high-velocity gas flow (shock-wave heating model). We developed the non-linear, time-dependent, and three-dimensional hydrodynamic simulation code for analyzing the dynamics of molten droplets exposed to the gas flow. We confirmed that our simulation results showed a good agreement in a linear regime with the linear solution analytically derived by Sekiya et al. (2003). We found that the non-linear terms in the hydrodynamical equations neglected by Sekiya et al. (2003) can cause the cavitation by producing negative pressure in the droplets. We discussed that the fragmentation through the cavitation is a new mechanism to determine the upper limit of chondrule sizes. We also succeeded t...
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...
On the simulation of shock-driven material mixing in high-Re flows (u)
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.
Wake Flow Simulations for a Mid-Sized Rim Driven Wind Turbine
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+
Numerical Simulation of Rarefied-Gas Flows about a Rotating Cylinder
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
Visualizing Vortices in Simulated Air Flow around Bat Wings during Flight
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
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
A front-tracking method for the simulation of three-phase flow in porous media
Stanford University, Dept. of Petroleum Engineering, 88 Green Earth Sciences Bldg., Stanford, CA 94305, USA, in- compressible fluids can be described by a 2×2 nongenuinely nonlinear, hyperbolic system. We in turn leads to simulation models with a very large number of grid blocks. As a result, there is and
Kwon, Kyung [Tuskegee Univ., Tuskegee, AL (United States); Fan, Liang-Shih [The Ohio State Univ., Columbus, OH (United States); Zhou, Qiang [The Ohio State Univ., Columbus, OH (United States); Yang, Hui [The Ohio State Univ., Columbus, OH (United States)
2014-09-30T23:59:59.000Z
A new and efficient direct numerical method with second-order convergence accuracy was developed for fully resolved simulations of incompressible viscous flows laden with rigid particles. The method combines the state-of-the-art immersed boundary method (IBM), the multi-direct forcing method, and the lattice Boltzmann method (LBM). First, the multi-direct forcing method is adopted in the improved IBM to better approximate the no-slip/no-penetration (ns/np) condition on the surface of particles. Second, a slight retraction of the Lagrangian grid from the surface towards the interior of particles with a fraction of the Eulerian grid spacing helps increase the convergence accuracy of the method. An over-relaxation technique in the procedure of multi-direct forcing method and the classical fourth order Runge-Kutta scheme in the coupled fluid-particle interaction were applied. The use of the classical fourth order Runge-Kutta scheme helps the overall IB-LBM achieve the second order accuracy and provides more accurate predictions of the translational and rotational motion of particles. The preexistent code with the first-order convergence rate is updated so that the updated new code can resolve the translational and rotational motion of particles with the second-order convergence rate. The updated code has been validated with several benchmark applications. The efficiency of IBM and thus the efficiency of IB-LBM were improved by reducing the number of the Lagragian markers on particles by using a new formula for the number of Lagrangian markers on particle surfaces. The immersed boundary-lattice Boltzmann method (IBLBM) has been shown to predict correctly the angular velocity of a particle. Prior to examining drag force exerted on a cluster of particles, the updated IB-LBM code along with the new formula for the number of Lagrangian markers has been further validated by solving several theoretical problems. Moreover, the unsteadiness of the drag force is examined when a fluid is accelerated from rest by a constant average pressure gradient toward a steady Stokes flow. The simulation results agree well with the theories for the short- and long-time behavior of the drag force. Flows through non-rotational and rotational spheres in simple cubic arrays and random arrays are simulated over the entire range of packing fractions, and both low and moderate particle Reynolds numbers to compare the simulated results with the literature results and develop a new drag force formula, a new lift force formula, and a new torque formula. Random arrays of solid particles in fluids are generated with Monte Carlo procedure and Zinchenko's method to avoid crystallization of solid particles over high solid volume fractions. A new drag force formula was developed with extensive simulated results to be closely applicable to real processes over the entire range of packing fractions and both low and moderate particle Reynolds numbers. The simulation results indicate that the drag force is barely affected by rotational Reynolds numbers. Drag force is basically unchanged as the angle of the rotating axis varies.
Numerical Simulation of the Flow of a Power Law Fluid in an Elbow Bend
Kanakamedala, Karthik
2010-07-14T23:59:59.000Z
widely used form of the general constitutive equation is the power law model. The one dimensional power law model during simple shear is given by, ??? = ? ? ? ?? ? where, ??? is the shear stress, ? is the consistency index ? ?? is the rate... institution. I would also like to thank the University for providing the supercomputing facilities which have been very helpful for performing the simulations. vi NOMENCLATURE ? Velocity vector p Hydrodynamic pressure ? Cauchy stress tensor...
Simulation of hydrogen adsorption systems adopting the flow through cooling concept
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Hardy, B.; Corgnale, C.; Chahine, R.; Cossement, D.; Tamburello, D.; Anton, D.
2014-10-01T23:59:59.000Z
Hydrogen storage systems based on adsorbent materials have the potential of achieving the U.S. Department of Energy (DOE) targets, especially in terms of gravimetric capacity. This paper deals with analysis of adsorption storage systems adopting the flow through cooling concept. By this approach the feeding hydrogen provides the needed cold to maintain the tank at low temperatures. Two adsorption systems have been examined and modeled adopting the Dubinin-Astakhov model, to see their performance under selected operating conditions. A first case has been analyzed, modeling a storage tank filled with carbon based material (namely MaxSorb®) and comparing the numerical outcomes withmore »the available experimental results for a 2.5 L tank. Under selected operating conditions (minimum inlet hydrogen temperature of approximately 100 K and maximum pressure on the order of 8.5 MPa) and adopting the flow through cooling concept the material shows a gravimetric capacity of about 5.7 %. A second case has been modeled, examining the same tank filled with metal organic framework material (MOF5®) under approximately the same conditions. The model shows that the latter material can achieve a (material) gravimetric capacity on the order of 11%, making the system potentially able to achieve the DOE 2017 target.« less
Roar Skartlien; Espen Sollum; Andreas Akselsen; Paul Meakin
2012-07-01T23:59:59.000Z
A 3D lattice Boltzmann model for two-phase flow with amphiphilic surfactant was used to investigate the evolution of emulsion morphology and shear stress in starting shear flow. The interfacial contributions were analyzed for low and high volume fractions and varying surfactant activity. A transient viscoelastic contribution to the emulsion rheology under constant strain rate conditions was attributed to the interfacial stress. For droplet volume fractions below 0.3 and an average capillary number of about 0.25, highly elliptical droplets formed. Consistent with affine deformation models, gradual elongation of the droplets increased the shear stress at early times and reduced it at later times. Lower interfacial tension with increased surfactant activity counterbalanced the effect of increased interfacial area, and the net shear stress did not change significantly. For higher volume fractions, co-continuous phases with a complex topology were formed. The surfactant decreased the interfacial shear stress due mainly to advection of surfactant to higher curvature areas. Our results are in qualitative agreement with experimental data for polymer blends in terms of transient interfacial stresses and limited enhancement of the emulsion viscosity at larger volume fractions where the phases are co-continuous.
Simulation of hydrogen adsorption systems adopting the flow through cooling concept
Hardy, B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Corgnale, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Chahine, R. [Univ. du Quebec a Trois-Rivieres, QC (Canada). Hydrogen Research Inst.; Cossement, D. [Univ. du Quebec a Trois-Rivieres, QC (Canada). Hydrogen Research Inst.; Tamburello, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Anton, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
2014-10-01T23:59:59.000Z
Hydrogen storage systems based on adsorbent materials have the potential of achieving the U.S. Department of Energy (DOE) targets, especially in terms of gravimetric capacity. This paper deals with analysis of adsorption storage systems adopting the flow through cooling concept. By this approach the feeding hydrogen provides the needed cold to maintain the tank at low temperatures. Two adsorption systems have been examined and modeled adopting the Dubinin-Astakhov model, to see their performance under selected operating conditions. A first case has been analyzed, modeling a storage tank filled with carbon based material (namely MaxSorb®) and comparing the numerical outcomes with the available experimental results for a 2.5 L tank. Under selected operating conditions (minimum inlet hydrogen temperature of approximately 100 K and maximum pressure on the order of 8.5 MPa) and adopting the flow through cooling concept the material shows a gravimetric capacity of about 5.7 %. A second case has been modeled, examining the same tank filled with metal organic framework material (MOF5®) under approximately the same conditions. The model shows that the latter material can achieve a (material) gravimetric capacity on the order of 11%, making the system potentially able to achieve the DOE 2017 target.
Hitoshi Miura; Taishi Nakamoto
2006-11-09T23:59:59.000Z
Millimeter-sized, spherical silicate grains abundant in chondritic meteorites, which are called as chondrules, are considered to be a strong evidence of the melting event of the dust particles in the protoplanetary disk. One of the most plausible scenarios is that the chondrule precursor dust particles are heated and melt in the high-velocity gas flow (shock-wave heating model). We developed the non-linear, time-dependent, and three-dimensional hydrodynamic simulation code for analyzing the dynamics of molten droplets exposed to the gas flow. We confirmed that our simulation results showed a good agreement in a linear regime with the linear solution analytically derived by Sekiya et al. (2003). We found that the non-linear terms in the hydrodynamical equations neglected by Sekiya et al. (2003) can cause the cavitation by producing negative pressure in the droplets. We discussed that the fragmentation through the cavitation is a new mechanism to determine the upper limit of chondrule sizes. We also succeeded to reproduce the fragmentation of droplets when the gas ram pressure is stronger than the effect of the surface tension. Finally, we compared the deformation of droplets in the shock-wave heating with the measured data of chondrules and suggested the importance of other effects to deform droplets, for example, the rotation of droplets. We believe that our new code is a very powerful tool to investigate the hydrodynamics of molten droplets in the framework of the shock-wave heating model and has many potentials to be applied to various problems.
Simulations of Blood Flow in Plain Cylindrical and Constricted Vessels with Single Cell Resolution
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.
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,
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.
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
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
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...
Time cycle analysis and simulation of material flow in MOX process layout
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.
NUMERICAL FLOW AND TRANSPORT SIMULATIONS SUPPORTING THE SALTSTONE FACILITY PERFORMANCE ASSESSMENT
Flach, G.
2009-02-28T23:59:59.000Z
The Saltstone Disposal Facility Performance Assessment (PA) is being revised to incorporate requirements of Section 3116 of the Ronald W. Reagan National Defense Authorization Act for Fiscal Year 2005 (NDAA), and updated data and understanding of vault performance since the 1992 PA (Cook and Fowler 1992) and related Special Analyses. A hybrid approach was chosen for modeling contaminant transport from vaults and future disposal cells to exposure points. A higher resolution, largely deterministic, analysis is performed on a best-estimate Base Case scenario using the PORFLOW numerical analysis code. a few additional sensitivity cases are simulated to examine alternative scenarios and parameter settings. Stochastic analysis is performed on a simpler representation of the SDF system using the GoldSim code to estimate uncertainty and sensitivity about the Base Case. This report describes development of PORFLOW models supporting the SDF PA, and presents sample results to illustrate model behaviors and define impacts relative to key facility performance objectives. The SDF PA document, when issued, should be consulted for a comprehensive presentation of results.
House Simulation Protocols Report | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
House Simulation Protocols Report House Simulation Protocols Report Report cover Building America's House Simulation Protocols report is designed to assist researchers in tracking...
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.
Simulations Data Simulation Type
Wang, Xiaorui "Ray"
to request different simulations data. The flow chart above demonstrates the different steps and options@ornl.gov) Autotune Drupal 7 CMS Current building energy models (BEMs), using EnergyPlus or other simulations, are unreliable because they have to constantly be calibrated to match actual energy usage data. Currently
Control-volume method for numerical simulation of two-phase immiscible flow in two-and
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
Rutqvist, J.
2011-01-01T23:59:59.000Z
geomechanics and reservoir simulation. Society of Petroleum Engineers (and geomechanics. Society of Petroleum Engineers Journal 11,
Zhong, L.
2014-01-01T23:59:59.000Z
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 and verified models were applied to obtain...
Hiler, E. A.; Bhuiyan, S. I.
1971-01-01T23:59:59.000Z
Two computer programs were developed. One simulated vertical unsteady infiltration through the surface into a homogeneous unsaturated soil. Simulation results were obtained for three different soils--Yolo light clay, Adelanto loam, and Pachappa loam...
Boyer, Edmond
the entire globe. RRMs have been introduced into earth system models (ESMs) to convert the runoff simulated
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
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
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.
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.
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.
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 blowouts result in disaster...
Abu-Hassoun, Amer H.
2009-05-15T23:59:59.000Z
Fluid flow mechanisms in a large naturally fractured heterogeneous carbonate reservoir were investigated in this manuscript. A very thin layer with high permeability that produces the majority of production from specific wells and is deemed...
Rasool, Syed Ahmed
1994-01-01T23:59:59.000Z
program. 4. 3 Flow chart for Bublp subroutine 5. 1 Pressure profiles for Well Tex A 10. . 5. 2 Pressure profiles for Well Tex A3. . 5. 3 Crossplot of PBHFp~, versus measured BHFP. 5. 4 Cmssplot of PttHppcurr versus measured BHFP 5. 5 Error... distribution for BHFP calculated by EOS. . . . . . . . . . . 5. 6 Error distribution for BHFP calculated by correlation. . . . . . . . . . . . . . . . . . . . . . 5. 7 Plot of depth versus flow patterns for Well 364 and Well 365 . . . . . . . . . 5. 8 Plot...
A four-equation two-phase flow model for sodium boiling simulation of LMFBR fuel assemblies
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 ...
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...
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.
Simulation of Strongly Heated Internal Gas Flows Using a Near-Wall Two-Equation Heat Flux Model
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)
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...
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
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.
Lo, Min-Hui; Famiglietti, James S; Yeh, P. J.-F.; Syed, T. H
2010-01-01T23:59:59.000Z
Calibration Using GRACE Data and Base Flow Estimates [ 17 ]ESTIMATION USING GRACE DATA base flow data. In this casemeasured GRACE data and estimated base flow simultaneously
Thanh D.B. Nguyen; Young-Il Lim; Seong-Joon Kim; Won-Hyeon Eom; Kyung-Seun Yoo [Hankyong National University, Jungangno (Republic of Korea). Laboratory of Functional Analysis of Complex Systems (FACS)
2008-11-15T23:59:59.000Z
A turbulent reacting flow computational fluid dynamics (CFD) model involving a droplet size distribution function in the discrete droplet phase is first built for selective noncatalytic reduction (SNCR) processes using urea solution as a NOx removal reagent. The model is validated with the experimental data obtained from a pilot-scale urea-based SNCR reactor installed with a 150 kW gas burner. New kinetic parameters of seven chemical reactions for the urea-based NOx reduction are identified and incorporated into the three-dimensional turbulent flow CFD model. The two-phase droplet model with the non-uniform droplet size is also combined with the CFD model to predict the trajectory of the droplets and to examine the mixing between the flue gas and reagents. The maximum NO reduction efficiency of about 80%, experimentally measured at the reactor outlet, is obtained at 940{degree}C and a normalized stoichiometric ratio (NSR) = 2.0 under the conditions of 11% excess air and low CO concentration (10-15 ppm). At the reaction temperature of 940{degree}C, the difference of a maximum of 10% between experiments and simulations of the NO reduction percentage is observed for NSR = 1.0, 1.5, and 2.0. The ammonia slip is overestimated in CFD simulation at low temperatures, especially lower than 900{degree}C. However, the CFD simulation results above 900{degree}C show a reasonable agreement with the experimental data of NOx reduction and ammonia slip as a function of the NSR. 31 refs., 3 figs., 6 tabs.
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...
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
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.
Muñoz, P A; Kilian, P; Büchner, J; Jenko, F
2015-01-01T23:59:59.000Z
In this work, we extend a comparison between gyrokinetic (GK) and fully kinetic Particle-in-Cell (PIC) simulations of magnetic reconnection in the limit of strong guide field started by TenBarge et al. [Phys. Plasmas 21, 020708 (2014)]. By using a different set of kinetic PIC and GK simulation codes (ACRONYM and GENE, respectively), we analyze the limits of applicability of the GK approach when comparing to the force free kinetic simulations in the low guide field (bg) regime. Here we report the first part of a much more extended comparison, focusing on the macroscopic effects of the electron flows. For a low beta plasma (beta_i = 0.01), it is shown that magnetic reconnection only displays similar features between both plasma models for higher kinetic PIC guide fields (bg>30) in the secondary magnetic islands than in the region close to the X points or separatrices (bg>5). Kinetic PIC low guide field runs (53) to be negligible due to the reduced reconnection rate and fluctuation level.
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.
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.
BGSU Libraries STUDENT ASSISTANT
Moore, Paul A.
BGSU Libraries STUDENT ASSISTANT EMPLOYMENT APPLICATION NAME LIBRARY EXPERIENCE: LOCATION:________________________________________________________________________ ________________________________________________________________________________________________ OTHER OFFICE/LIBRARY SKILLS
Lo, Min-Hui; Famiglietti, James S; Yeh, P. J.-F.; Syed, T. H
2010-01-01T23:59:59.000Z
model using GRACE water storage and estimated base flow data,model using GRACE water storage and estimated base flow datawith esti- mated base flow data in the model calibration.
Executive Assistant to the Vice-President
Michelson, David G.
Administrative Assistant Murray Armstrong Administrative Assistant Tangerine Twiss Research Partnership
M E Dieckmann; A Bret
2008-12-09T23:59:59.000Z
Two charge- and current neutral plasma beams are modelled with a one-dimensional PIC simulation. The beams are uniform and unbounded. The relative speed between both beams is 0.4c. One beam is composed of electrons and protons and one out of protons and negatively charged oxygen (dust). All species have the temperature 9 keV. A Buneman instability develops between the electrons of the first beam and the protons of the second beam. The wave traps the electrons, which form plasmons. The plasmons couple energy into the ion acoustic waves, which trap the protons of the second beam. A proton phase space hole grows, which develops through its interaction with the oxygen and the heated electrons into a rarefaction pulse. This pulse drives a strong ion acoustic double layer, which accelerates a beam of electrons to about 50 MeV, which is comparable to the proton kinetic energy. The proton distribution eventually evolves into an electrostatic shock. Beams of charged particles moving at such speeds may occur in the foreshock of supernova remnant shocks. This double layer is thus potentially relevant for the electron acceleration (injection) into the diffusive shock acceleration by supernova remnants shocks.
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...
Hartmann, Andreas; Clauser, Christoph
2008-01-01T23:59:59.000Z
Development of geothermal energy and basin-scale simulations of fluid and heat flow both suffer from uncertain physical rock properties at depth. Therefore, building better prognostic models are required. We analysed hydraulic and thermal properties of the major rock types in the Molasse Basin in Southern Germany. On about 400 samples thermal conductivity, density, porosity, and sonic velocity were measured. Here, we propose a three-step procedure with increasing complexity for analysis of the data set: First, univariate descriptive statistics provides a general understanding of the data structure, possibly still with large uncertainty. Examples show that the remaining uncertainty can be as high as 0.8 W/(m K) or as low as 0.1 W/(m K). This depends on the possibility to subdivide the geologic units into data sets that are also petrophysically similar. Then, based on all measurements, cross-plot and quick-look methods are used to gain more insight into petrophysical relationships and to refine the analysis. Be...
Weatherization Assistance Program
Broader source: Energy.gov [DOE]
This fact sheet provides an overview of the U.S. Department of Energys Weatherization Assistance Program.
Rezvyi, Aleksey
2002-01-01T23:59:59.000Z
The coolant flow instability, apparent in the coolant mass flow fluctuations in the separate parallel heating channels and also in a closed loop of the primary circuit under some operating conditions, is observed in the core fuel assemblies of light...
Simulation effectively sites surge-relief facilities on Saudi pipeline
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.
Blood damage measures for ventricular assist device modeling
Natelson, Douglas
of implantable ventricular assist devicesin particular, continuous- flow axial and centrifugal pumpsoffers hope challenge that needs to be addressed in the design phase of blood pumps is the elevated level of shear of exposure. The distribution of the shear stress levels in a complex flow field of a rotary blood pump
Miniaturization of a left ventricular assist device
Milios, Gregory Scott
1996-01-01T23:59:59.000Z
The ventricular assist device under investigation in this study is the multiple disk centrifugal pump developed by Miller [32, 33, 34]. The pump design is based on that invented by Nikola Tesla and is termed the TAMU-MDP pump, standing for the Texas A... of the National Institute of Health (NIH) as being an accurate provider of the typical flow regime and pressure profile experienced by the human heart. As the Tesla pump is intended for use as a left ventricular assist device, only the systemic vasculature has...
Assistance Focus: Africa (Brochure)
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.
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.
Administrative Business Assistant
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
ASSISTED ELECTRONIC COMMUNICATION IN
;Department of Health Project 121-7184 Final Report 3 Executive Summary In the Assisted Electronic Project 121-7184 Final Report - 05.04.04 Kettering General NHS Hospital Trust University of Hertfordshire of Health Project 121-7184 Final Report 2 KEY to Common Abbreviations used: AEC(P) Assisted Electronic
Title: Marketing Assistant Description
Schweik, Charles M.
Title: Marketing Assistant Description: The UMass Amherst Career Services Office is searching for a student interested in marketing. The Marketing Assistant will work closely with our in-office marketing Brainstorm new and exciting marketing strategies, including social media Participate and contribute
Moridis, George; Freeman, Craig
2013-09-30T23:59:59.000Z
We developed two new EOS additions to the TOUGH+ family of codes, the RealGasH2O and RealGas . The RealGasH2O EOS option describes the non-isothermal two-phase flow of water and a real gas mixture in gas reservoirs, with a particular focus in ultra-tight (such as tight-sand and shale gas) reservoirs. The gas mixture is treated as either a single-pseudo-component having a fixed composition, or as a multicomponent system composed of up to 9 individual real gases. The RealGas option has the same general capabilities, but does not include water, thus describing a single-phase, dry-gas system. In addition to the standard capabilities of all members of the TOUGH+ family of codes (fully-implicit, compositional simulators using both structured and unstructured grids), the capabilities of the two codes include: coupled flow and thermal effects in porous and/or fractured media, real gas behavior, inertial (Klinkenberg) effects, full micro-flow treatment, Darcy and non-Darcy flow through the matrix and fractures of fractured media, single- and multi-component gas sorption onto the grains of the porous media following several isotherm options, discrete and fracture representation, complex matrix-fracture relationships, and porosity-permeability dependence on pressure changes. The two options allow the study of flow and transport of fluids and heat over a wide range of time frames and spatial scales not only in gas reservoirs, but also in problems of geologic storage of greenhouse gas mixtures, and of geothermal reservoirs with multi-component condensable (H2O and CH4) and non-condensable gas mixtures. The codes are verified against available analytical and semi-analytical solutions. Their capabilities are demonstrated in a series of problems of increasing complexity, ranging from isothermal flow in simpler 1D and 2D conventional gas reservoirs, to non-isothermal gas flow in 3D fractured shale gas reservoirs involving 4 types of fractures, micro-flow, non-Darcy flow and gas composition changes during production.
Khandare, Milind Nandkumar
2012-02-14T23:59:59.000Z
design are either overly simplified or incapable of taking into account all the features such as cavitation, air entrainment etc., affecting the performance of a SFD. On the other hand, experimental investigation of flow field and dynamic performance...
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...
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...
S. A. Voloshin
2002-11-20T23:59:59.000Z
Recent experimental results on directed and elliptic flow, theoretical developments, and new techniques for anisotropic flow analysis are reviewed.
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...
Assistant Vice President Advancement Marketing &
Bob Thomas Assistant Vice President Advancement Marketing & Communications N:\\groups\\handbook\\ Org Design Open Information Tech Web Design Lisa Wilton Assistant Director Paula Davenport Editor MSU Alumni
Weatherization Assistance Program Technical Assistance Center
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.
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.
Mutiscale Modeling of Segregation in Granular Flows
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.
Knowledge Assisted Visualization Knowledge-assisted visualization of seismic data
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
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
Weatherization Assistance Program (WAP)
Broader source: Energy.gov [DOE]
Through the Weatherization Assistance Program (WAP), the U.S. Department of Energy (DOE) issues grants to states, territories, and some Indian tribes to improve the energy efficiency of low-income...
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....
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.
Hanold, R.J.
1983-12-01T23:59:59.000Z
The two-phase flow program is directed at understanding the hydrodynamics of two-phase flows. The two-phase flow regime is characterized by a series of flow patterns that are designated as bubble, slug, churn, and annular flow. Churn flow has received very little scientific attention. This lack of attention cannot be justified because calculations predict that the churn flow pattern will exist over a substantial portion of the two-phase flow zone in producing geothermal wells. The University of Houston is experimentally investigating the dynamics of churn flow and is measuring the holdup over the full range of flow space for which churn flow exists. These experiments are being conducted in an air/water vertical two-phase flow loop. Brown University has constructed and is operating a unique two-phase flow research facility specifically designed to address flow problems of relevance to the geothermal industry. An important feature of the facility is that it is dedicated to two-phase flow of a single substance (including evaporation and condensation) as opposed to the case of a two-component two-phase flow. This facility can be operated with horizontal or vertical test sections of constant diameter or with step changes in diameter to simulate a geothermal well profile.
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
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...
Electromagnetically Induced Flows Michiel de Reus
Vuik, Kees
Electromagnetically Induced Flows in Water Michiel de Reus 8 maart 2013 () Electromagnetically Conclusion and future research () Electromagnetically Induced Flows 2 / 56 #12;1 Introduction 2 Maxwell Navier Stokes equations 5 Simulations 6 Conclusion and future research () Electromagnetically Induced
Numerical Investigation of turbulent coupling boundary layer of air-water interaction flow
Liu, Song, S.M. Massachusetts Institute of Technology
2005-01-01T23:59:59.000Z
Air-water interaction flow between two parallel flat plates, known as Couette flow, is simulated by direct numerical simulation. The two flowing fluids are coupled through continuity of velocity and shear stress condition ...
Technical Assistance to Developers
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.
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
Khandare, Milind Nandkumar
2012-02-14T23:59:59.000Z
combinations of rotor whirl speed, operating pressures and with and without incorporating the cavitation model. The fluid used in the simulations was ISO VG 2 Mobil Velocite no. 3. After the successful use of the cavitation model in the 2D case, a 3D model...
Fluid Flow Modeling in Fractures
Sarkar, Sudipta
2004-01-01T23:59:59.000Z
In this paper we study fluid flow in fractures using numerical simulation and address the challenging issue of hydraulic property characterization in fractures. The methodology is based on Computational Fluid Dynamics, ...
Particle simulation of vibrated gas-fluidized beds of cohesive fine powders
Sung Joon Moon; I. G. Kevrekidis; S. Sundaresan
2006-08-09T23:59:59.000Z
We use three-dimensional particle dynamics simulations, coupled with volume-averaged gas phase hydrodynamics, to study vertically vibrated gas-fluidized beds of fine, cohesive powders. The volume-averaged interstitial gas flow is restricted to be one-dimensional (1D). This simplified model captures the spontaneous development of 1D traveling waves, which corresponds to bubble formation in real fluidized beds. We use this model to probe the manner in which vibration and gas flow combine to influence the dynamics of cohesive particles. We find that as the gas flow rate increases, cyclic pressure pulsation produced by vibration becomes more and more significant than direct impact, and in a fully fluidized bed this pulsation is virtually the only relevant mechanism. We demonstrate that vibration assists fluidization by creating large tensile stresses during transient periods, which helps break up the cohesive assembly into agglomerates.
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:
Medical Robots Surgical Assistants
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
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.
Bélanger, Geneviève; Park, Jong-Chul, E-mail: belanger@lapp.in2p3.fr, E-mail: jcpark@kias.re.kr [Laboratoire d'Annecy-le-Vieux de Physique Théorique, Université de Savoie, CNRS, BP 110, 74941 Annecy-Le-Vieux (France)
2012-03-01T23:59:59.000Z
We explore a class of dark matter models with two dark matter candidates, only one interacts with the standard model sector. One of the dark matter is thermalized with the assistance of the other stable particle. While both stable particles contribute to the total relic density only one can elastically scatter with nuclei, thus effectively reducing the direct detection rate.
Research Assistant Tracking Code
Simmons, Craig A.
with neuroimaging technologies (MRI, EEG, MEG, PET, etc.). Working with technicians and scientists in collaborating & image processing, #12;statistics/data analysis, MRI and/or PET data acquisition Shell scripting in Unix control and processing, software development and data visualization. Assisting in maintaining
Mechanical Engineering Assistant Professor
Chandy, John A.
Mechanical Engineering Xu Chen Assistant Professor xchen@uconn.edu http://xchen.lab.uconn.edu From Cooking to Advanced Manufacturing --Controls, Automation, and Beyond 2014 UCONN open house #12;Mechanical of Diana Kuan #12;Mechanical Engineering The Cooking Procedure #12;Mechanical Engineering The Difference
Administrative Business Assistant
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
Archives Research Assistant Classification: Student Assistant 3 (LSA 3)
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
Microblower assisted barometric valve
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.
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...
Vijaykumar, Anand
2011-02-22T23:59:59.000Z
.05mm and clearance= 1.27mm (50 mil). The rotor is maintained initially at an eccentricity of 50% (25mil). The 3D modeling is based on the actual seal geometry used in the experiments. The entire geometry is meshed using a hexahedral grid which.... Numerical Simulation Model Five Test Cases Were Run 1. 50Mil clearance, 25Mil eccentricity, Circular orbit, 60hz case with whirl. 15 2. 50Mil clearance, 25Mil eccentricity, Circular orbit 60hz, Coordinate transformation. 3. 50Mil clearance, 25...
Plant analyzer development for high-speed interactive simulation of BWR plant transients
Wulff, W.; Cheng, H.S.; Mallen, A.N.
1986-01-01T23:59:59.000Z
Advanced modeling techniques have been combined with modern, special-purpose peripheral minicomputer technology to develop a plant analyzer which provides realistic and accurate predictions of plant transients and severe off-normal events in nuclear power plants through on-line simulations at speeds of approximately 10 times faster than actual process speeds. The new simulation technology serves not only for carrying out routinely and efficiently safety analyses, optimizations of emergency procedures and design changes, parametric studies for obtaining safety margins and for generic training but also for assisting plant operations. Five modeling principles are presented which serve to achieve high-speed simulation of neutron kinetics, thermal conduction, nonhomogeneous and nonequilibrium two-phase flow coolant dynamics, steam line acoustical effects, and the dynamics of the balance of plant and containment systems, control systems and plant protection systems. 21 refs.
Development of A Microwave Assisted Particulate Filter Regeneration System
Popuri, Sriram
2001-08-05T23:59:59.000Z
The need for active regeneration of diesel particulate filters and the advantages of microwave assisted regeneration are discussed. The current study has multiple objectives, which include developing a microwave assisted particulate filter regeneration system for future generation light-duty diesel applications, including PNGV type applications. A variable power 2.0 kW microwave system and a tuned waveguide were employed. Cavity geometry is being optimized with the aid of computational modeling and temperature measurements during microwave heating. A wall-flow ceramic-fiber filter with superior thermal shock resistance, high filtration efficiency, and high soot capacity was used. The microwave assisted particulate filter regeneration system has operated for more than 100 hours in an engine test-cell with a 5.9-liter diesel engine with automated split exhaust flow and by-pass flow capabilities. Filter regeneration was demonstrated using soot loads up to 10 g/liter and engine exhaust at idling flow rates as the oxygen source. A parametric study to determine the optimal combination of soot loading, oxidant flow rate, microwave power and heating time is underway. Preliminary experimental results are reported.
Energy Department Assistant Secretary Patricia Hoffman Addresses...
Assistant Secretary Patricia Hoffman Addresses 2011 FERC Reliability Technical Conference Energy Department Assistant Secretary Patricia Hoffman Addresses 2011 FERC...
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...
Lagrangian methods for ballistic impact simulations/
Tupek, Michael Ronne
2010-01-01T23:59:59.000Z
This thesis explores various Lagrangian methods for simulating ballistic impact with the ultimate goal of finding a universal, robust and scalable computational framework to assist in the design of armor systems. An overview ...
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.
CFD analysis of laminar oscillating flows
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.
Numerical simulation of the impeller tip clearance effect on centrifugal compressor performance
Hoenninger, Corbett Reed
2001-01-01T23:59:59.000Z
This thesis presents the numerical simulation of flow in centrifugal compressors. A three-dimensional Navier-Stokes solver was employed to simulate flow through two centrifugal compressors. The first compressor simulated was the NASA low speed...
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...
SPE-169507-MS Artificial Intelligence (AI) Assisted History Matching
Mohaghegh, Shahab
SPE-169507-MS Artificial Intelligence (AI) Assisted History Matching Alireza Shahkarami, Shahab D a successful history matching project. The pattern recognition capabilities of Artificial Intelligence and Data the history matching process. SRM is an intelligent prototype of the full-field reservoir simulation model
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... Reservoirs Simulation of Infinite Cylindrical Reservoirs. . . Simulation of Wellbore Storage Simulation of Near Wellbore Skin. . . . . . . . . . . . . . . . Negative Skin. Simulation of Bounded Reservoirs. . . . . . . . . . . . . . . . Constant Pressure...
Machine Assisted Organic Synthesis
Ley, Steven V.; Fitzpatrick, Daniel E.; Myers, Rebecca M.; Battilocchio, Claudio; Ingham, Richard. J.
2015-01-01T23:59:59.000Z
not known on this planet. Machines can only assist in this process and are never fully able to mimic or automate the abilities of an innovative bench chemist but they help by generating more time to think and design new processes. The first review... reactions need to be conducted over a full working day. While cryo-cooling devices for batch reactions are available, these are limited to smaller scales. We too have controlled reactions at low temperatures by submerging reactor coils in cooling baths...
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...
Wang, Xi-guang; Guo, Guang-hua, E-mail: guogh@mail.csu.edu.cn; Nie, Yao-zhuang; Xia, Qing-lin; Tang, Wei [School of Physics and Electronics, Central South University, Changsha 410083 (China)] [School of Physics and Electronics, Central South University, Changsha 410083 (China); Wang, D. [Department of Physics, National University of Defense Technology, Changsha 410073 (China)] [Department of Physics, National University of Defense Technology, Changsha 410073 (China); Zeng, Zhong-ming [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China)] [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China)
2013-12-23T23:59:59.000Z
We have studied the current-induced displacement of a 180° Bloch wall by means of micromagnetic simulation and analytical approach. It is found that the adiabatic spin-transfer torque can sustain a steady-state domain wall (DW) motion in the direction opposite to that of the electron flow without Walker Breakdown when a transverse microwave field is applied. This kind of motion is very sensitive to the microwave frequency and can be resonantly enhanced by exciting the domain wall thickness oscillation mode. A one-dimensional analytical model was established to account for the microwave-assisted wall motion. These findings may be helpful for reducing the critical spin-polarized current density and designing DW-based spintronic devices.
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...
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.
Liles, D.R.
1982-01-01T23:59:59.000Z
Internal boundaries in multiphase flow greatly complicate fluid-dynamic and heat-transfer descriptions. Different flow regimes or topological configurations can have radically dissimilar interfacial and wall mass, momentum, and energy exchanges. To model the flow dynamics properly requires estimates of these rates. In this paper the common flow regimes for gas-liquid systems are defined and the techniques used to estimate the extent of a particular regime are described. Also, the current computer-code procedures are delineated and introduce a potentially better method is introduced.
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.
Advanced wellbore thermal simulator GEOTEMP2 research report
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.
Laser Assisted Emittance Exchange
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.
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.
A Bicycle Electric Assist Unit
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 ...
Computational Methods for Design-Assisted Mask Flows
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
Flow Split Venturi, Axially-Rotated Valve
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.
The Time-Dependent NavierStokes Equations Laminar Flows
John, Volker
Chapter 6 The Time-Dependent NavierStokes Equations Laminar Flows Remark 6.1. Motivation to distinguish between laminar and turbulent flows. It does not exist an exact definition of these terms. From the point of view of simulations, a flow is considered to be laminar, if on reasonable grids all flow
Proof-assistants using Dependent Type Henk Barendregt
Barendregt, Henk
.3 Autarkic Computations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 5 Proof assistants
Office of the Assistant General Counsel for Procurement and Financial...
Procurement and Financial Assistance Office of the Assistant General Counsel for Procurement and Financial Assistance The Office of the Assistant General Counsel for Procurement...
Assisted distillation of quantum coherence
Chitambar, E; Rana, S; Bera, M N; Adesso, G; Lewenstein, M
2015-01-01T23:59:59.000Z
We introduce and study the task of assisted coherence distillation. This task arises naturally in bipartite systems where both parties work together to generate the maximal possible coherence on one of the subsystems. Only incoherent operations are allowed on the target system while general local quantum operations are permitted on the other, an operational paradigm that we call local quantum-incoherent operations and classical communication (LQICC). We show that the asymptotic rate of assisted coherence distillation for pure states is equal to the coherence of assistance, a direct analog of the entanglement of assistance, whose properties we characterize. Our findings imply a novel interpretation of the von Neumann entropy: it quantifies the maximum amount of extra quantum coherence a system can gain when receiving assistance from a collaborative party. Our results are generalized to coherence localization in a multipartite setting and possible applications are discussed.
Characterizing Flow in Oil Reservoir Rock Using Smooth Particle Hydrodynamics
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 ...
Feedback control of flow separation using synthetic jets
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...
Lagrangian Simulation of Combustion
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.
GRADUATE COLLEGE TERMINATION OF GRADUATE ASSISTANT
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
Clinical Assistant Professor Human Resource Development
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
Simulation of geothermal subsidence
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)
The bubbly-slug transition in a high velocity two phase flow
Griffith, P.
1964-01-01T23:59:59.000Z
A possible mechanism for the transition between bubbly and slug flow is proposed and tested in a simulated slug flow system. No sudden collapse of slug flow with increasing velocity is found and it is concluded that: a. ...
Federal Energy Management Program (FEMP) Technical Assistance...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Program (FEMP) Technical Assistance Request Portal User Guide Federal Energy Management Program (FEMP) Technical Assistance Request Portal User Guide Document explains how...
Graduate Assistant Commitment Form Eagle ID:________________________
Hutcheon, James M.
Graduate Assistant Commitment Form 1 Eagle ID:________________________ Name:_____________________________________________ Supervisor:______________________________________Dept./Unit unites within the University. Research Assistant (RA) primary responsibility
Environmental Policy and Assistance | Department of Energy
Office of Environmental Management (EM)
Environmental Policy and Assistance Environmental Policy and Assistance The Department of Energys (DOE) goal is to carry out all cleanup operations in a manner that protects...
START Renewable Energy Project Development Technical Assistance...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
START Renewable Energy Project Development Technical Assistance START Renewable Energy Project Development Technical Assistance The U.S. Department of Energy (DOE) Office of Indian...
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...
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...
Profiles in Leadership: Christopher Smith, Assistant Secretary...
Christopher Smith, Assistant Secretary for Fossil Energy Profiles in Leadership: Christopher Smith, Assistant Secretary for Fossil Energy July 15, 2015 - 8:19am Addthis Profiles in...
NUMERICAL SIMULATION OF INCOMPRESSIBLE FLOWS IN ...
PDEs by boundary layer or quasi-geostrophic approximations, as well as imposing ... are to be completed with admissible initial and boundary conditions. ... eral practice, especially for spectral approximations, to treat the nonlinear terms .... spectral-Galerkin method in [19] is as good, if not more efficient and accurate, as.
Acoustic Behavior of Flow From Fracture To Wellbore
Chen, Kyle
2015-04-23T23:59:59.000Z
. The study is conducted on a laboratory setup that simulates the downhole condition when fluid flows from the fracture and perforation tunnel to the wellbore. To better simulate the downhole condition, a fracture cell and wellbore assembly are designed...
Adiabatic thermal Child-Langmuir flow
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 ...
Dynamics of Polymers in Flowing Colloidal Suspensions
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 ...
Engineering Organization Chart Assistant Dean
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
Assistant Professor Agricultural Systems Modeler
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
Senthil S. Vel Assistant Professor
Vel, Senthil
Senthil S. Vel Assistant Professor Department of Mechanical Engineering Brian P. Baillargeon Graduate Student Department of Mechanical Engineering, University of Maine, Orono, Maine 04469 Analysis of Static Deformation, Vibration and Active Damping of Cylindrical Composite Shells with Piezoelectric Shear
Environmentally assisted cracking in light water reactors
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.
Stress-Assisted Corrosion in Boiler Tubes
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.
TCP Flow Controls Matthew Roughan
Roughan, Matthew
connections Much is known about the qualitative performance of the Internet the Internet works! Little is known about the quantitative performance of the TCP flow controls mostly by simulation, few analytic Paxson, "Measurements and Analysis of End-to-End Internet Dynamics" PhD Thesis Van Jacobson, "Congestion
The MIT Design Advisor : simple and rapid energy simulation of early-stage building designs
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 ...
Geothermal direct-heat utilization assistance
Not Available
1992-12-01T23:59:59.000Z
Progress on technical assistance, R D activities, technology transfer, and geothermal progress monitoring is summarized.
MATPOWER's Extensible Optimal Power Flow Architecture
Tesfatsion, Leigh
1 MATPOWER's Extensible Optimal Power Flow Architecture Ray D. Zimmerman, Member, IEEE, Carlos E the optimal power flow (OPF) architecture implemented in MATPOWER, an open-source Mat- lab power system simulation package. It utilizes an extensible architecture that allows the user to easily add new variables
Micromechanics of emergent patterns in plastic flows
Grant, Martin
Micromechanics of emergent patterns in plastic flows Santidan Biswas1 , Martin Grant2 , Indradev and Development Division, Tata Steel Limited, Jamshedpur 83100, India. Crystalline solids undergo plastic crystalline solids exist in polycrystalline form. Simulating plastic flows in polycrystalline solids has wide
Direct Numerical Simulation of Autoignition in a Jet in a Cross...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Direct Numerical Simulation of Autoignition in a Jet in a Cross-Flow Direct Numerical Simulation of Autoignition in a Jet in a Cross-Flow PI Name: Christos Frouzakis PI Email:...
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
Simulation- Assisted Audit of an Air Conditioned Office Building
Bertagnolio, S.; Lebrun, J.; Hannay, J.; Silva, C. A.
2008-01-01T23:59:59.000Z
and nominal performances and capacities can be automatically computed through a pre-sizing calculation or defined basing on default values given in European standards (prEN 13053 and 13773). The implementation of this global building-HVAC model... and nominal performances and capacities can be automatically computed through a pre-sizing calculation or defined basing on default values given in European standards (prEN 13053 and 13773). The implementation of this global building-HVAC model...
Van den Engh, G.
1995-11-07T23:59:59.000Z
A Faraday cage is described which encloses the flow chamber of a cytometer. Ground planes associated with each field deflection plate inhibit electric fields from varying the charge on designated events/droplets and further concentrates. They also increase forces applied to a passing charged event for accurate focus while concomitantly inhibiting a potential shock hazard. 4 figs.
Ko, Min Seok
2009-05-15T23:59:59.000Z
This dissertation presents a numerical simulation of three-dimensional flow and heat transfer in a channel with a backward-facing step. Flow was considered to be steady, incompressible, and laminar. The flow medium was treated to be radiatively...
DFSP - a data flow signal processor
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.
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...
Regionally compartmented groundwater flow on Mars Keith P. Harrison1
Harrison, Keith
Regionally compartmented groundwater flow on Mars Keith P. Harrison1 and Robert E. Grimm1 Received] Groundwater flow on Mars likely contributed to the formation of several types of morphologic and mineralogic of groundwater flow required for their formation. For groundwater simulation purposes, a global Martian aquifer
Zonal flow dynamics in the double tearing mode with antisymmetric shear flows
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.
Magnetic Amplifier for Power Flow Control
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.
LANL, Sandia celebrate success at New Mexico Small Business Assistance...
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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)...
Federal Renewable Energy Project Assistance and Resources | Department...
Assistance and Resources Federal Renewable Energy Project Assistance and Resources Federal agencies can get renewable energy project assistance from the U.S. Department of Energy's...
Career Information Assistant Description & Duties
Toronto, University of
-task is an asset * Interest in libraries, archives, records management, museums, information management, and other for specific fields (libraries, archives, records management, museums, etc.) * Assist with development browsing and searching for relevant information * Experience with social media an asset * Ability to multi
New Mexico Small Business Assistance
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
Vacuum-assisted cell loading enables shear-free mammalian microfluidic Martin Kolnik,a
Hasty, Jeff
Vacuum-assisted cell loading enables shear-free mammalian microfluidic culture{ Martin Kolnik,a Lev that are extremely isolated from potentially damaging flow effects. We utilize a transient on-chip vacuum to remove by generating a localized temporary on-chip vacuum in channels directly adjacent to the trapping regions
Techniques of High Performance Reservoir Simulation for Unconventional Challenges
Wang, Yuhe
2013-12-05T23:59:59.000Z
. require coupled flow and poroelastic simulation. These features, in turn, bring a heavy burden on linear solvers. The booming unconventional plays such as shale/tight oil in North America demand reservoir simulation techniques to handle more physics (or...
Loop simulation capability for sodium-cooled systems
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 ...
Wang, Junjian; Kang, Qinjun; Rahman, Sheik S
2015-01-01T23:59:59.000Z
The lattice Boltzmann method (LBM) has experienced tremendous advances and been well accepted as a popular method of simulation of various fluid flow mechanisms on pore scale in tight formations. With the introduction of an effective relaxation time and slip boundary conditions, the LBM has been successfully extended to solve micro-gaseous related transport and phenomena. As gas flow in shale matrix is mostly in the slip flow and transition flow regimes, given the difficulties of experimental techniques to determine extremely low permeability, it appears that the computational methods especially the LBM can be an attractive choice for simulation of these micro-gaseous flows. In this paper an extensive overview on a number of relaxation time and boundary conditions used in LBM-like models for micro-gaseous flow are carried out and their advantages and disadvantages are discussed. Furthermore, potential application of the LBM in flow simulation in shale gas reservoirs on pore scale and representative elementary...
Energy Technical Assistance: Industrial Processes Program
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...
Job Position Description Job Title: Office Assistant
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
Job Position Description Job Title: Locksmith Assistant
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
Energy Technical Assistance: Industrial Processes Program
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...
Obtaining Disaster Assistance for Public Infrastructure
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...
START Renewable Energy Project Development Assistance | Department...
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...
Graduate Research Assistant, Student Mem. ASME
Qu, Weilin
, with bubbly flow occurring only occasion- ally; stratified and churn flow were never observed. A flow pattern boiling offers many advantages such as low thermal resistance, small flow rate and coolant inventory
Jet quenching and elliptic flow
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.
Groundwater Recharge Simulator M. Tech. Thesis
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
Gradual Variation Analysis for Groundwater Flow
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...
Computer Assisted Parallel Program Generation
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 ...
Computer Assisted Virtual Environment - CAVE
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.
Assistive Devices for the Home
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...
Precision electron flow measurements in a disk transmission line.
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.
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
Induction motor modeling in stability simulation: Final report
Carlson, D.L.; Fedora, C.M.
1988-12-01T23:59:59.000Z
The objective of this project is to help utilities choose models of large motor loads when simulating electric system transient stability behavior during severe contingencies. Various motor models were evaluated through comparisons between simulations and field recordings obtained in this project. Guidelines are developed to assist engineers in applying typically available data describing large motors. 10 refs., 35 figs.
Numerical Simulation of Transpiration Cooling
to facilitate such numerical simulations for a carbon/carbon material mounted in the side wall of a hot gas channel that are able to capture a spatially varying interplay between the hot gas flow and the coolant itself. This calls for new cooling technologies, for example, in the combustion chamber of the rocket
Plug flow and the breakdown of Bagnold scaling in cohesive granular flows
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.
Improvement of semiconductor optical amplifier dynamic behaviour by assist light injection
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
In Vitro Evaluation of Multiobjective Hemodynamic Control of a Heart-Assist Pump
Paden, Brad
simulator using a HeartQuest centrifugal blood pump (CF4b, MedQuest Products, Salt Lake City, UT). To avoidIn Vitro Evaluation of Multiobjective Hemodynamic Control of a Heart-Assist Pump KWAN-WOONG GWAK blood pumps has now been recognized, modern control concepts have started to be evaluated
7. Simulations of PlasmaPhysical Processes in Clusters
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
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
A penalization method for calculating the flow beneath travelling water waves of large amplitude
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.
Anisotropic flow in striped superhydrophobic channels
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.
Anisotropic flow in striped superhydrophobic channels
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.
Get Assistance | Department of Energy
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journal Article)41clothThe Bonneville Power AdministrationHawaiiEnergyFlorida Julyanalysis,GeoSiphonBiomass andOfficeGet Assistance Get
Financial Assistance | Department of Energy
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journal Article) |govInstrumentsmfrirt DocumentationSitesWeather6Environmental1 |MAgnEt for InvEstMEnt1 National Nuclear0Assistance Financial
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 ...
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 ...
RELAP5 subcooled critical flow model verification
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.
Assistance Focus: Asia/Pacific Region (Brochure)
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.
Assistance Focus: Latin America/Caribbean (Brochure)
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.
FLOW-THROUGH POROUS ELECTRODES
Trainham, III, James Arthur
2011-01-01T23:59:59.000Z
porous electrodes A flow-redox battery using flow-by porousconfigurations for flow redox battery applications: (i) thetrue in battery applications, Flow..through porous
Effects of non-Darcy flow on pressure buildup analysis of hydraulically fractured gas reservoirs
Alvarez Vera, Cesar
2001-01-01T23:59:59.000Z
fracture parameters reliably, simulation history matching is the appropriate method to correctly analyze buildup pressure response from hydraulically fractured reservoirs with significant non-Darcy flow effects....
Numerical studies on two-way coupled fluid flow and geomechanics in hydrate deposits
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.
Multiphase flow calculation software
Fincke, James R. (Idaho Falls, ID)
2003-04-15T23:59:59.000Z
Multiphase flow calculation software and computer-readable media carrying computer executable instructions for calculating liquid and gas phase mass flow rates of high void fraction multiphase flows. The multiphase flow calculation software employs various given, or experimentally determined, parameters in conjunction with a plurality of pressure differentials of a multiphase flow, preferably supplied by a differential pressure flowmeter or the like, to determine liquid and gas phase mass flow rates of the high void fraction multiphase flows. Embodiments of the multiphase flow calculation software are suitable for use in a variety of applications, including real-time management and control of an object system.
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...
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.
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,...
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...
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...
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
K. A. Thole^ Assistant Professor.
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
Numerical modeling of species transport in turbulent flow and experimental study on aerosol sampling
Vijayaraghavan, Vishnu Karthik
2007-04-25T23:59:59.000Z
Numerical simulations were performed to study the turbulent mixing of a scalar species in straight tube, single and double elbow flow configurations. Different Reynolds Averaged Navier Stokes (RANS) and Large Eddy Simulation (LES) models were used...
Relationship Between Soil Moisture Storage and Deep Percolation and Subsurface Return Flow
Nieber, J. L.
1984-01-01T23:59:59.000Z
A simulation study was performed to analyze the relationship between the volume of moisture stored in a soil profile and the rate of percolation and subsurface return flow. The simulation study was derived on the basis of the Richards equation...
Building Galaxies with Simulations
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.
Friction and the oscillatory motion of granular flows
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.
Real-time state estimation of laboratory flows
Stransky, Scott (Scott M.)
2007-01-01T23:59:59.000Z
In this project, we use a real time computer model to simulate a differentially heated laboratory annulus. The laboratory annulus allows us to study chaotic flows typical of the atmosphere. Our objective is to bring the ...
Scaled Experimental Modeling of VHTR Plenum Flows
ICONE 15
2007-04-01T23:59:59.000Z
Abstract The Very High Temperature Reactor (VHTR) is the leading candidate for the Next Generation Nuclear Power (NGNP) Project in the U.S. which has the goal of demonstrating the production of emissions free electricity and hydrogen by 2015. Various scaled heated gas and water flow facilities were investigated for modeling VHTR upper and lower plenum flows during the decay heat portion of a pressurized conduction-cooldown scenario and for modeling thermal mixing and stratification (“thermal striping”) in the lower plenum during normal operation. It was concluded, based on phenomena scaling and instrumentation and other practical considerations, that a heated water flow scale model facility is preferable to a heated gas flow facility and to unheated facilities which use fluids with ranges of density to simulate the density effect of heating. For a heated water flow lower plenum model, both the Richardson numbers and Reynolds numbers may be approximately matched for conduction-cooldown natural circulation conditions. Thermal mixing during normal operation may be simulated but at lower, but still fully turbulent, Reynolds numbers than in the prototype. Natural circulation flows in the upper plenum may also be simulated in a separate heated water flow facility that uses the same plumbing as the lower plenum model. However, Reynolds number scaling distortions will occur at matching Richardson numbers due primarily to the necessity of using a reduced number of channels connected to the plenum than in the prototype (which has approximately 11,000 core channels connected to the upper plenum) in an otherwise geometrically scaled model. Experiments conducted in either or both facilities will meet the objectives of providing benchmark data for the validation of codes proposed for NGNP designs and safety studies, as well as providing a better understanding of the complex flow phenomena in the plenums.
Chemically assisted mechanical refrigeration process
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.
Chemically assisted mechanical refrigeration process
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.
Chemically assisted mechanical refrigeration process
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.
Chemically assisted mechanical refrigeration process
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.
Kaiper, G V
2003-11-21T23:59:59.000Z
This report covers the following: (1) Explanation of Charts Showing Freshwater Flow in 1995; (2) Estimated U.S. Freshwater Flow in 1995 (chart); (3) Estimated California Freshwater Flow in 1995 (chart); (4) Estimated New Mexico Freshwater Flow in 1995 (chart); and (5) Web locations and credits.
AGREEMENT FOR DOE-FUNDED TECHNOLOGY ASSISTANCE
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
Renewable Energy Project Development Assistance (Fact Sheet)
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.
Assistant or Associate Professor in Sedimentology
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
Effective Community-Wide Policy Technical Assistance
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
Gautham Rao Assistant Professor of History
Carlini, David
Gautham Rao Assistant Professor of History American University 4400 Massachusetts Avenue NW@american.edu Appointments Assistant Professor, Department of History, American University, Washington, DC 9/2012-Present/2009-6/2009 Samuel I. Golieb Fellow in Legal History, New York University Law School, New York, NY 8
Instructions for use JICA's Assistance in Health
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
Spanish & Portuguese -Teaching Assistants Spring 2014
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
Portable wastewater flow meter
Hunter, Robert M. (320 S. Wilson Ave., Bozeman, MT 59715)
1999-02-02T23:59:59.000Z
A portable wastewater flow meter particularly adapted for temporary use at a single location in measuring the rate of liquid flow in a circular entrance conduit of a sewer manhole both under free flow and submerged, open channel conditions and under fill pipe, surcharged conditions, comprising an apparatus having a cylindrical external surface and an inner surface that constricts the flow through the apparatus in such a manner that a relationship exists between (1) the difference between the static pressure head of liquid flowing through the entrance of the apparatus and the static pressure head of liquid flowing through the constriction, and (2) the rate of liquid flow through the apparatus.
Portable wastewater flow meter
Hunter, Robert M. (320 S. Wilson Ave., Bozeman, MT 59715)
1990-01-01T23:59:59.000Z
A portable wastewater flow meter particularly adapted for temporary use at a single location in measuring the rate of liquid flow in a circular entrance conduit of a sewer manhole both under free flow and submerged, open channel conditions and under full pipe, surcharged conditions, comprising an apparatus having a cylindrical external surface and an inner surface that constricts the flow through the apparatus in such a manner that a relationship exists between (1) the difference between the static pressure head of liquid flowing through the entrance of the apparatus and the static pressure head of liquid flowing through the constriction, and (2) the rate of liquid flow through the apparatus.
Oxygen-assisted multipass cutting of carbon fiber reinforced plastics with ultra-short laser pulses
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.
Characterizing flow fluctuations with moments
Rajeev S. Bhalerao; Jean-Yves Ollitrault; Subrata Pal
2015-01-22T23:59:59.000Z
We present a complete set of multiparticle correlation observables for ultrarelativistic heavy-ion collisions. These include moments of the distribution of the anisotropic flow in a single harmonic, and also mixed moments, which contain the information on correlations between event planes of different harmonics. We explain how all these moments can be measured using just two symmetric subevents separated by a rapidity gap. This presents a multi-pronged probe of the physics of flow fluctuations. For instance, it allows to test the hypothesis that event-plane correlations are generated by non-linear hydrodynamic response. We illustrate the method with simulations of events in A MultiPhase Transport (AMPT) model.
Minnesota, University of
Abstract-- We describe an inexpensive in-home monitoring system designed to assist patients wireless sensors, including motion, pressure, door, flow, accelerometer, magnetometer, temperature, light daily activities in a home setting. In particular, the system is intended to help such patients plan
POWER FLOW ANALYSIS OF ELECTROSTRICTIVE ACTUATORS DRIVEN BYSWITCHMODE AMPLIFIERS
Lindner, Douglas K.
is developed with includes a dynamic structural model of the actuator, a dynamic model of the power electronics. It is shown that an outer acoustic control loop can modify this mechanical admittance and optimize the power, the power flow between the electrical and mechanical systems is analyzed through simulation. The flow
A mixed-dimensional finite volume method for multiphase flow
Cirpka, Olaf Arie
; Numerical reservoir simulation; Fractured reser- voir; Mixed-dimensional Finite Volume Method; MultigridA mixed-dimensional finite volume method for multiphase flow in fractured porous media Volker method for the fully coupled, fully implicit discretization of two-phase flow in fractured porous media
MHD Simulation of Flare Experiment Jeffrey Kollasch, Prof. James F. Drake, Dr. Marc Swisdak
Anlage, Steven
MHD Simulation of Flare Experiment Jeffrey Kollasch, Prof. James F. Drake, Dr. Marc Swisdak of Prof. James Drake and Dr. Marc Swisdak as well as valued assistance from Prof. Paul Cassak and Raymond