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Tomographic immersed boundary method for permeability prediction of realistic porous media: simulation and experimental validation

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AIP Conference Proceedings 2011年第1期1453卷 321-326页

作者： Lopez Penha, D.J. Geurts, B.J. Nordlund, M. Kuczaj, A.K. Zinovik, I. Winkelmann, C. Mikhal, J. Multiscale Modeling Simulation MESA Institute for Nanotechnology University of Twente 7500 AE Enschede P.O. Box 217 Netherlands Anisotropic Turbulence Department of Applied Physics Eindhoven University of Technology 5600 MB Eindhoven P.O. Box 513 Netherlands Philip Morris International Research Development Philip Morris Products S.A. 2000 Neuchâtel Quai Jeanrenaud 5 Switzerland

In this paper we demonstrate the ability of a volume-penalizing immersed boundary method to predict pore-scale fluid transport in realistic porous media. A numerical experiment is designed that recreates the exact conditions of a real flow experiment through a fibrous porous medium. Under a constant volumetric flow rate air is forced through the porous sample and the pressure drop across its length is accurately measured. The exact pore geometry is obtained using highresolution micro-computed tomography, and the data is, after processing, directly inserted into the flow solver. simulations are performed on a uniform Cartesian grid, spanning the entire physical domain (i.e., including both fluid and solid regions)- a feature which represents one of the major benefits of volume penalization. We demonstrate that the numerical results agree well with the experiment and that an error of approximately < 10% is attainable on a grid of 512×256×256 cells. © 2012 American Institute of Physics.

关键词： Direct numerical simulation Immersed boundary method Laminar flow Permeability Porous medium Tomographic reconstruction

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Testing of SLA-561V in NASA-Ames' turbulent flow duct with augmented radiative heating

Testing of SLA-561V in NASA-Ames' turbulent flow duct with a...

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42nd AIAA Thermophysics Conference 2011

作者： Sepka, Steven A. Wray, Alan Prabhu, Dinesh Kornienko, Robert S. Radbourne, Chris A. ERC Inc. NASA Ames Research Center Thermal Protection Materials Branch Moffett Field CA 94035 United States NASA Ames Research Center Fundamental Modeling and Simulation Branch Moffett Field CA 94035 United States ERC Inc. NASA Ames Research Center Aerothermodynamics Branch Moffett Field CA 94035 United States NASA Ames Research Center NASA-Ames Applied Manufacturing Division Moffett Field CA 94035 United States

ISBN: (纸本)9781624101465

As part of the Mars Science Laboratory (MSL) thermal protection system material test and qualification program, SLA-561V, the candidate heat shield material, was tested in the NASA Ames Turbulent Flow Duct (TFD) Facility. Normally the TFD wall opposite the test model is water-cooled copper. However, for these tests, in an effort to increase the heat flux applied to the test sample, the TFD facility was modified to place a ceramic plate in the wall opposite the test model. Installing a non-water-cooled ceramic plate allows it to absorb convective heating, and radiate the energy back to the test model as the ceramic plate heats up. Results of these specialized tests to establish the performance of SLA-561V under turbulent flow conditions are provided in the present paper. The tests showed extensive formation of glass melt and melt flow on a scale never before observed for SLA-561V.

关键词： Turbulent flow

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Sonic boom computations for a Mach 1.6 cruise low boom configuration and comparisons with wind tunnel data

Sonic boom computations for a Mach 1.6 cruise low boom confi...

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29th AIAA applied Aerodynamics Conference 2011

作者： Elmiligui, Alaa A. Wilcox, Floyd Bangert, Linda Cliff, Susan E. Nemec, Marian Aftosmis, Michael J. Parlette, Edward Configuration Aerodynamics Branch M/S 499-1 Hampton VA 23681 United States NAS Applications Branch M/S 258-2 Moffett Field CA 94035 United States Science and Technology Corp. Applied Modeling and Simulation Branch MS 258-5 Moffett Field CA 94035 United States VIGYAN Inc. 30 Research Dr MS 130 Hampton VA 23666 United States

ISBN: (纸本)9781624101458

Accurate analysis of sonic boom pressure signatures using computationalfluid- dynamics techniques remains quite challenging. Although CFD shows accurate predictions of flow around complex configurations, generating grids that can resolve the sonic boom signature far away from the aircraft is a challenge. The test case chosen for this study corresponds to an experimental wind-tunnel test that was conducted to measure the sonic boom pressure signature of a low boom configuration designed by Gulfstream Aerospace Corporation. Two widely used NASA codes, USM3D and AERO, are examined to determine their ability to accurately capture sonic boom signature. Numerical simulations are conducted for a free-stream Mach number of 1.6, angle of attack of 0.3, and Reynolds number of 3.85x106 based on model reference length. Flow around the low boom configuration in free air and inside the NASA Langley Unitary Plan Wind Tunnel are computed. Results from the numerical simulations are compared with wind tunnel data. The effects of viscous and turbulence modeling along with tunnel walls on the computed sonic boom signature are presented and discussed.

关键词： NASA

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Management of C4I and M&S data standards with modular OWL ontologies

Management of C4I and M&S data standards with modular OWL on...

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Spring simulation Interoperability Workshop 2011, 2011 Spring SIW

作者： Gupton, Kevin Abbott, Jeff Blais, Curtis Diallo, Saikou Y. Heffner, Kevin Turnitsa, Chuck Applied Research Laboratories University of Texas at Austin 10000 Burnet Rd. Austin TX 78758 United States Systems Architect CAE USA Professional Services 3501 Quadrangle BLVD. Orlando FL 32817 United States MOVES Institute Naval Postgraduate School Monterey CA 93943 United States Virginia Modeling Analysis and Simulation Center - VMASC Old Dominion University. 1030 University Blvd. Suffolk VA 23435 United States Pegasus Simulation Plateau Mont-Royal PS PO Box 47552 Montreal QC H2H 2S8 Canada

ISBN: (纸本)9781617824241

Standard information exchange data models (IEDMs), such as the Joint Consultation Command and Control IEDM (JC3IEDM) managed by the Multilateral Interoperability Programme (MIP) and the National Information Exchange Model (NIEM) managed by the US Department of Homeland Security, often are expressed as XML Schema Definition (XSD) documents. This choice of model representation comes with the benefits of a widely adopted format and a well-supported XML toolset and libraries. Although XML, as a technology, has been an enabler in achieving model alignment and interoperability among C4I and M&S systems, several key issues have not been fully addressed. For instance, XML does not provide a standard means for representing semantics. This means that XML expressions generally cannot be interpreted by applications in a meaningful manner unless specific code has been added for this purpose. In addition, systems utilizing multiple IEDMs are faced with difficult mapping and model translation tasks that cannot easily be automated. Furthermore, the use of multiple IEDMs creates significant maintainability and scalability challenges associated with the use of the relevant standards and specifications. As the user-base of a data standard grows, the need for distributed management and extensibility becomes critical. Developer communities are driven to make extensions to the data models to support their domain- and system-specific requirements. This results in laborious, manual, often unsustainable extension-management processes. In particular, the MIP-JC3IEDM, SISO Military Scenario Definition Language (MSDL), and US Joint Forces Command (JFCOM) Order of Battle Service (OBS) XML specifications have growing user-bases, and while they share many concepts, no clear maintainable alignment has occurred among them. Although some efforts toward alignment across IEDMs have occurred, no standard, maintainable process or methodology for this has been proposed. This paper describes a framework f

关键词： Ontology

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Large-scale computations for stability analysis of launch vehicles using cluster computers

Large-scale computations for stability analysis of launch ve...

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作者： Guruswamy, Guru Applied Modeling Simulation Branch NASA Advanced Supercomputing Division Ames Research Center Moffett Field CA United States

ISBN: (纸本)9781600867422

A procedure is developed to generate a large aerodynamic database suitable for the static stability analysis of launch vehicles in the transonic regime by using the Navier-Stokes equations. Effects of structural deformations are also included using modal representation. A large number of cases are computed within practical time limitations by using efficient protocols suitable for massively parallel computations on large single-image clusters. Results are validated with wind tunnel measurements. Performance of a large-scale cluster is also studied.

关键词： Launch vehicles

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Mapping data models and data dictionaries-removing the ambiguity

Mapping data models and data dictionaries-removing the ambig...

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Fall simulation Interoperability Workshop 2010, 2010 Fall SIW

作者： Gupton, Kevin Allcorn, Eric Scrudder, Roy Carlton, Bruce Modeling and Simulation Information Management Group Applied Research Laboratories University of Texas at Austin 10000 Burnet Rd. Austin TX 78758 United States

ISBN: (纸本)9781617389085

To achieve system-to-system interoperability in any context-M&S or otherwise - an alignment of data concepts and data formats must occur. Each domain, community, and organization may share basic data concepts, but the context and scope in which those data concepts are used varies, resulting in data incompatibility. Data format or syntax mismatches can be reconciled through lossy or lossless translation, but this has utility only if we can first establish meaningful alignment among the data dictionaries and ontologies of the disparate communities. Traditionally, the mappings among data dictionaries and data models have been captured in document tables and spreadsheets, and the way in which mappings are categorized varies from effort to effort. In this paper, we explore the potential for and benefits of machine-understandable alignment of data dictionaries using structured ontology and linked data techniques. As an example, we address the alignment of two widely used geospatial data dictionaries: the SEDRIS Environmental Data Coding Specification (EDCS) and the National System for Geospatial-Intelligence (NSG) Feature Data Dictionary (NFDD). We will describe how mapping information can be gleaned from data dictionaries and data models, captured using ontological and linked data techniques, and then applied to automating the data translation process.

关键词： Interoperability

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Use cases and criteria for assessing M&S reuse repositories

Use cases and criteria for assessing M&S reuse repositories

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Fall simulation Interoperability Workshop 2010, 2010 Fall SIW

作者： Riggs, William C. Morse, Katherine L. Gustavson, Paul Rutherford, Hart Petty, Mikel D. Johns Hopkins University Applied Physics Laboratory 11100 Johns Hopkins Road Laurel MD 20723-6099 United States SimVentions Inc. 11905 Bowman Drive Fredericksburg VA 22408-7344 United States Center for Modeling Simulation and Analysis University of Alabama in Huntsville Von Braun Research Hall D-14 301 Sparkman Drive Huntsville AL 35899 United States

ISBN: (纸本)9781617389085

The Department of Defense (DoD) Live-Virtual-Constructive (LVC) Architecture Roadmap Implementation project is engaged in planning and implementing key enhancements to the capabilities, products, and processes used in the practice of modeling and simulation (M&S) within the department. One part of that effort is concerned with the reuse of software, data, and other assets in DoD M&S development, which has been identified by the M&S Steering Committee as an important requirement. Currently, such reuse is neither as frequent nor as effective as it could be. As a consequence, the potential benefits of reuse to the DoD enterprise are not being fully realized. To increase the effectiveness of reuse, enhancements to DoD M&S repositories are needed. A team led by the Johns Hopkins University applied Physics Laboratory examined existing repository and registry capabilities for M&S reuse and compared these capabilities to the required mechanisms for sharing and reuse as described in the LVC Architecture Roadmap. An assessment of multiple existing repositories using a carefully developed set of M&Soriented evaluation criteria was conducted to identify needed enhancements. The evaluation criteria were developed from two sources. The first was a set of twenty-two M&S use cases designed to cover the full range of interactions and transactions M&S software producers, integrators, and consumers might have with an M&S repository. The use cases were analyzed to identify the requirements and criteria they implied for such repositories. The second was a set of existing repository assessment criteria lists that were not M&S-specific. These general purpose criteria were reviewed, and those pertinent to M&S repositories were selected and revised to enhance their M&S relevance. This paper identifies and explains the M&S use cases, describes the assessment criteria, and reports how the former were used to drive and organize the latter in the repository assessment.

关键词： Digital storage

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simulation of impaction filtration by a porous filter

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AIP Conference Proceedings 2010年第1期1254卷 129-134页

作者： L. Ghazaryan D. J. Lopez Penha B. J. Geurts S. Stolz C. Winkelmann aMultiscale Modeling and Simulation Department of Applied Mathematics Faculty EEMCS University of Twente P.O. Box 217 7500 AE Enschede The Netherlands bAnisotropic Turbulence Department of Applied Physics Eindhoven University of Technology P.O. Box 513 5600 MB Eindhoven The Netherlands cPhilip Morris Products S.A. PMI Research & Development Quai Jeanrenaud 5 2000 Neuchâtel Switzerland

We present a new numerical approach for estimating filtration through porous media from first principles. We numerically simulate particle motion as arises in a carrier gas flow. The filtration we look at occurs due to impaction of particles with obstructing surfaces that are contained in the solid filter. We consider the case when the motion of particles is governed by linear Stokes‐drag, which is characterized by the particle relaxation time. The gas‐particle interaction is modeled by using the Eulerian‐Lagrangian approach and one‐way coupling of the phases. In this case the carrier flow drags along the particles, without being affected by the motion of the particles. The gas flow is governed by Navier‐Stokes equations for incompressible fluids and is calculated numerically using finite‐volume discretization that is based on an energy conserving skew‐symmetric discretization. We apply an immersed boundary (IB) method to capture the detailed flow in the porous filter, in which we explicitly incorporate flow around all small‐scale features that make up the inner structure of the porous filter. To validate and develop our method we consider a porous medium composed of a staggered arrangement of square rods in 3D, which was already extensively considered in the literature for flow computation. This is a stepping‐stone case on the way of simulating filtration of aerosol particles in complex, realistic filters. Based on results of our simulations we investigate the decay of the number of particles as a function of time. We focus on the dependence of the decay‐rate on the Reynolds number of the gas and the inertial effects of the particles. For a range of particle relaxation times we observe a strong influence of the Reynolds number on filtration rate. A non‐monotonic dependence of the filtration efficiency on Stokes number at different flow conditions is observed, hinting at qualitative differences in the motion of the aerosol ensemble through the structured filter.

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Coalition Battle Management Language (C-BML) phase 1 Specification development

Coalition Battle Management Language (C-BML) phase 1 Specifi...

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simulation Interoperability Workshop Spring 2008, SIW Spring 2008

作者： Blais, Curtis Diallo, Saikou Farmer, Gary Levine, Stan Turnitsa, Chuck MOVES Institute Naval Postgraduate School Monterey CA 93943 United States Virginia Modeling Analysis and Simulation Center Old Dominion University Suffolk VA United States Applied Research Laboratory University of Texas Austin TX United States C4I Center George Mason University Fairfax VA United States

ISBN: (纸本)9781605601083

The Coalition Battle Management Language (C-BML) is intended to be an unambiguous language for expressing and exchanging plans, orders, and reports across command and control (C2) systems, modeling and simulation (M&S) systems, and robotics systems. In March 2006, the simulation Interoperability Standards Organization (SISO) approved initiation of a Product Development Group (PDG) to generate a standard and guidance document for C-BML. The PDG laid out a 3-phase development effort to (1) specify a sufficient data model to unambiguously define a set of military orders using the Joint Command, Control, and Consultation Information Exchange Data Model (JC3IEDM) as a starting point;(2) develop a formal grammar (lexicon and production rules) to formalize the definition of orders, requests, and reports;and (3) develop a formal battle management ontology to enable conceptual interoperability across software systems. This paper reports on the technical approach and status of development of the C-BML Phase 1 Specification.

关键词： Interoperability

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IMPLEMENTATION OF MIXED METHODS AS FINITE DIFFERENCE METHODS AND APPLICATIONS TO NONISOTHERMAL MULTIPHASE FLOW IN POROUS MEDIA

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Journal of Computational Mathematics 2006年第3期24卷 281-294页

作者： Zhang-xin Chen Xi-jun Yu Center for Scientific Computation Box 750156 Southern Methodist University Dallas TX 75275-0156 USA Research Center for Science Xi'an Jiaotong University Xi'an 710049 China Center for Advanced Reservoir Modeling and Simulation College Vof Engineering'PekingI University China Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing 100088 China

In this paper we consider mixed finite element methods for second order elliptic problems. In the case of the lowest order Brezzi-Douglas-Marini elements （if d = 2） or Brezzi- Douglas-Duran-Fortin elements （if d = 3） on rectangular parallelepipeds, we show that the mixed method system, by incorporating certain quadrature rules, can be written as a simple, cell-centered finite difference method. This leads to the solution of a sparse, positive semidefinite linear system for the scalar unknown. For a diagonal tensor coefficient, the sparsity pattern for the scalar unknown is a five point stencil if d = 2, and seven if d = 3. For a general tensor coefficient, it is a nine point stencil, and nineteen, respectively. Applications of the mixed method implementation as finite differences to nonisothermal multiphase, multicomponent flow in porous media are presented.

关键词： Finite difference Implementation Mixed method Error estimates Superconvergence Tensor coefficient Nonisothermal multiphase Multicomponent flow Porousmedia.

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