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Recent advances in EdgeCFD on wave-structure interaction and turbulence modeling

Marine Systems and Ocean Technology 2014年第1期9卷 49-58页

作者： Elias, Renato N. Coutinho, Alvaro L. G. A. Gonçalves, Milton A. Cortês, Adriano M. A. Drummond Alves, José L. Guevara, Nestor O. Silva, Carlos E. Correa, Bruno Rochinha, Fernando A. Guerra Bernadá, Gabriel M. Lins, Erb F. de Carvalho e Silva, Daniel F. High Performance Computing Center COPPE/Federal University of Rio de Janeiro Rio de JaneiroRJ Brazil Laboratory for Computational Methods in Engineering COPPE/Federal University of Rio de Janeiro Rio de JaneiroRJ Brazil Mechanical Engineering Program COPPE/Federal University of Rio de Janeiro Rio de JaneiroRJ Brazil PETROBRAS Research Center Rio de Janeiro RJ Brazil

The computation of free surface flows is challenging since waves are highly nonlinear and commonly present merging, fragmentation and cusps, leading to the use of interface capturing ALE approaches. Turbulence is also important on several offshore applications. In this work we report recent advances of EdgeCFD to simulate these problems. EdgeCFD is a fully implicit 3D incompressible stabilized parallel edge-based finite element flow solver associated to the Volume-of-Fluid (VoF) method. The VoF marking function is also solved by a fully implicit parallel edge-based finite element formulation. Turbulence in EdgeCFD is treated within the Large Eddy Simulation (LES) framework. The performance and accuracy of EdgeCFD is tested in the simulation waves and in the interaction between waves and a semisubmersible structure. We also access the performance of several LES models on the simulation of the flow around a cylinder at Re ynolds 3,900. © 2014, Sociedade Brasileira de Engenharia Naval.

关键词： Finite element method

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Implicit large-eddy simulation of isotropic turbulent mixing

Implicit large-eddy simulation of isotropic turbulent mixing

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43rd AIAA Fluid Dynamics Conference

作者： Wachtor, A.J. Grinstein, F.F. DeVore, C.R. Ristorcelli, J.R. Los Alamos National Laboratory Chemical Diagnostics and Engineering P.O. Box 1663 MS J565 Los Alamos NM 87545 United States Los Alamos National Laboratory X-Computational Physics: Methods and Algorithms Los Alamos NM 87545 United States Laboratory for Advanced Computational Physics Laboratory for Computational Physics and Fluid Dynamics Naval Research Laboratory Washington DC 20375 United States

ISBN: (纸本)9781624102141

We address turbulent scalar mixing with a prescribed mean scalar gradient in the implicit large-eddy simulation (ILES) context. The focus is on the performance of ILES to capture the mixing dynamics due to large-scale entrainment and intermediate scale convective stirring in forced compressible isotropic turbulence. ILES is based on a multi-dimensional flux corrected transport algorithm with separate low wave number forcing of solenoidal and dilatational velocity components. ILES is shown to capture dominant aspects of the mixing transition as function of effective Reynolds number determined by grid resolution.

关键词： Reynolds number

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A stabilized edge-based finite element approach to wave-structure interaction assessment

A stabilized edge-based finite element approach to wave-stru...

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ASME 2013 32nd International Conference on Ocean, Offshore and Arctic engineering, OMAE 2013

作者： Elias, Renato N. Coutinho, Alvaro L.G.A. Gonçalves Jr., Milton A. Cortês, Adriano M.A. Alves, José L. Drummond Guevara, Nestor O. Silva, Carlos E. Correa, Bruno Rochinha, Fernando A. Bernadá, Gabriel M. Guerra De Carvalho E Silva, Daniel F. High Performance Computing Center COPPE Federal University of Rio de Janeiro P.O. Box 68506 RJ 21945-970 - Rio de Janeiro Brazil Laboratory for Computational Methods in Engineering COPPE Federal University of Rio de Janeiro P.O. Box 68552 RJ 21949-900 - Rio de Janeiro Brazil Mechanical Engineering Program COPPE Federal University of Rio de Janeiro P.O. Box 68506 RJ 21945-970 - Rio de Janeiro Brazil PETROBRAS Research Center Av. Horacio Macedo 850 Rio de Janeiro Brazil

ISBN: (纸本)9780791855317

Complex flows involving waves and free-surfaces occur in several problems in hydrodynamics, such as fuel or water sloshing in tanks, waves breaking in ships, offshore platforms motions, wave action on harbors and coastal areas. The computation of such highly nonlinear flows is challenging since waves and free-surfaces commonly present merging, fragmentation and cusps, leading to the use of interface capturing Arbitrary Lagrangian-Eulerian (ALE) approaches. In such methods the interface between the two fluids is captured by the use of a marking function that is transported in a flow field. In this work we simulate these problems with a 3D incompressible SUPG/PSPG parallel edge-based finite element flow solver associated to the Volume-of-Fluid (VOF) method. The hyperbolic equation for the transport of the marking function is also solved by a fully implicit parallel edge-based SUPG finite element formulation. Global mass conservation is enforced adding or removing mass proportionally to the absolute value of the normal velocity at the interface. All those techniques were successfully implemented in a computational code, which has been suitably used to carry out several studies. The performance and accuracy of the proposed solution method is tested in the simulation waves and in the interaction between waves and a semisubmersible structure. Results count on the establishment of a relaxation zone close to the domain outflow, which partially absorbs incoming waves, avoiding their reflection. Copyright © 2013 by ASME.

关键词： Hyperbolic functions

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Scale-space line curvature estimation for straight line and circle detection

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Pattern Recognition and Image Analysis 2012年第2期22卷 360-370页

作者： Semeikina, E.V. Yurin, D.V. Krylov, A.S. Chung, Kuo-Liang Huang, Yong-Huai Laboratory of Mathematical Methods of Image Processing Faculty of Computational Mathematics and Cybernetic Moscow State University Moscow 119991 Russia Department of Computer Science and Information Engineering National Taiwan University of Science and Technology No. 43 Section 4 Keelung Road Taipei 10672 Taiwan Institute of Computer and Communication Engineering and Department of Electronic Engineering Jinwen University of Science and Technology No. 99 An-Chung Road Hsin-Tien Taipei 23154 Taiwan

A scale-space algorithm for estimating the local curvature of lines (edges or isolines) is presented. Two variants of edge curvature estimation based on differential invariants are suggested and compared. The first variant uses the edge curvature formula derived in the paper and the second is based on image preprocessing, which allows one to use the isoline curvature formula for edge curvature estimation. An analysis of scale selection needed to reach a desired accuracy is presented. Also, noise influence analysis has been performed. The application of curvature estimation to detection of straight lines and circles is suggested and implemented. Curvature information usage in parametric curve detection speeds up search algorithms and makes the results more stable. © 2012 Pleiades Publishing, Ltd.

关键词： Curve fitting

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A residual Monte Carlo method for spatially discrete, angularly continuous radiation transport

A residual Monte Carlo method for spatially discrete, angula...

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2012 ANS Annual Meeting and Embedded Topical Meeting: Nuclear Fuels and Structural Materials for the Next Generation Nuclear Reactors, NFSM 2012

作者： Wollaeger, Ryan T. Densmore, Jeffery D. Department of Nuclear Engineering and Engineering Physics University of Wisconsin Madison 410 ERB 1500 Engineering Drive Madison WI 53706 United States Computational Physics and Methods Group Los Alamos National Laboratory MS D409 P.O. Box 1663 Los Alamos NM 87545 United States

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EdgeCFD-ALE: A stabilized finite element system for fluid-structure interaction in offshore engineering

EdgeCFD-ALE: A stabilized finite element system for fluid-st...

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ASME 2012 31st International Conference on Ocean, Offshore and Arctic engineering, OMAE 2012

作者： Alves, José L.D. Silva, Carlos E. Guevara, Nestor O. Coutinho, Alvaro L.G.A. Elias, Renato N. Rochinha, Fernando F.A. Martins, Marcos A.D. Ferreira, Marcos D.A.S. Silva, Daniel F.C. Laboratory for Computational Methods in Engineering Civil Engineering Department COPPE/UFRJ Rio de Janeiro RJ 21941-972 Brazil High Performance Computing Center Mechanical Engineering Department COPPE/UFRJ Rio de Janeiro RJ 21945-970 Brazil PETROBRAS Research Center Av. Horacio Macedo 850 Rio de Janeiro RJ Brazil

ISBN: (纸本)9780791844915

This work presents the development of EdgeCFD-ALE, a finite element system for complex fluid-structure interactions designed for offshore hydrodynamics. Sloshing of liquids in tanks, wave breaking in ships, offshore platforms motions and green water on decks are important examples of these problems. The software uses edge-based parallel stabilized finite elements for the Navier-Stokes equations and the Volume-Of-Fluid method for the free-surface, both described by an Arbitrary Lagrangian Eulerian (ALE) formulation. Turbulence in is treated by a Smagorinsky model. Mesh updating is accomplished by a parallel edge-based solution of a non-homogeneous scalar diffusion problem in each spatial coordinate. Boundary conditions involve the motion of the immersed body's surface, i.e., the fluid-structure interface, taken as the Lagrangian portion of the domain in the overall problem. The simulation capabilities of the present software are demonstrated in the solution of two problems, the interaction of two cylinders in tandem and the free fall of a sphere. Copyright © 2012 by ASME.

关键词： Fluid structure interaction

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Discussing validation of 3D character animation demonstrating Ushiro-Ukemi pedagogical progression

Discussing validation of 3D character animation demonstratin...

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14th International Conference on Human-Computer Interaction, HCI International 2011

作者： De Alencar Carvalho, Mauro Cesar Gurgel Carvalho, Bruno Martins De Paiva Carvalho, Felipe Leal Dias Oliveira Jr., Heidi Cunha, Gerson Gomes Landau, Luiz Dantas, Estélio Henrique Martin LaCiMovi - Movement Science Laboratory Pedro II School Rio de Janeiro Brazil LAMCE-Laboratory of Computational Methods in Engineering COPPE-UFRJ Brazil LABIMH - Laboratory of Human Bio-kinetics UNIRIO Rio de Janeiro Brazil

ISBN: (纸本)9783642220944

This study was designed to verify the evidence of validity, through: 1) literature review about ushiro-ukemi pedagogical progression. 2) An expert performed the movement and it was recorded to develop the animation. 3) Finally, an evaluation of 3D character animations processes by other experts' opinions. 13 experts have evaluated three affirmatives through the Likert scale, and answered one question, also in ordinal scale, about the quality of the animation. The calculated medians for the first, second and third affirmatives were 5, 5 and 5 (fully agree), but, only for the 3rd affirmative about sitting ushiro-ukemi, the median was 4 (agree). The percentage of answers that scored higher than agree varied from 84,6 to 100%. The median of the 3D character animation was very good (4) and the percentage of acceptance was 100% (≥ good). The found definitional evidence of validity for these animations ensured their application in a learning material. © 2011 Springer-Verlag.

关键词： Animation

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The borehole method of rock massive stress state estimation

The borehole method of rock massive stress state estimation

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2011 International Conference on Mechanical, Industrial, and Manufacturing engineering (MIME 2011)

作者： Valery Pavlov Sergey Serdyukov Peter Martynuk Laboratory of computational methods in geophysics Institute of Petroleum Geology and Geophysics Novosibirsk Laboratory for oil production wave-engineering Institute of Mining Novosibirsk

In permeable rock the hydraulic fracturing stress measurement is carried out using such impenetrable shell as a packer and a sleeve that prevents from fluid injection into the fracture and *** stress states are determined from several fracture reopening pressures on condition that cracks have different orientation in reference to a maximum *** modeling of this problem shows the gradual character of the crack opening in the borehole and the influence of an indefinable initial crack length on the reopening pressure value Pr of other *** a solution the using of a singular radial fracture and the measuring of fracture opening value on the outline dependence of the pressure in the impenetrable shell are *** fractures are induced by hydraulic fracturing in *** test of the solution is carried out using singular integral equations of linear fracture *** fracture opening pressure and fracture opening value on the outline dependence of the fracture opening portion length and external stress field is *** principal stress ratio estimation algorithm is *** ratio of principal stresses is an additional parameter and it is used to find out the stress with the fracture reopening pressure on the borehole wall.

关键词： hydraulic fracturing stress measuring,sleeve fracturing,numerical modeling

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Mean-field regime of trapped dipolar Bose-Einstein condensates in one and two dimensions

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Physical Review A 2010年第4期82卷 043623-043623页

作者： Yongyong Cai Matthias Rosenkranz Zhen Lei Weizhu Bao Department of Mathematics National University of Singapore 119076 Singapore School of Mathematical Sciences Fudan University Shanghai 200433 China Key Laboratory of Nonlinear Mathematical Models and Methods of Ministry of Education Fudan University Shanghai 200433 China Shanghai Key Laboratory for Contemporary Applied Mathematics Fudan University Shanghai 200433 China Center for Computational Science and Engineering National University of Singapore 117543 Singapore

We derive rigorous one- and two-dimensional mean-field equations for cigar- and pancake-shaped dipolar Bose-Einstein condensates with arbitrary polarization angle. We show how the dipolar interaction modifies the contact interaction of the strongly confined atoms. In addition, our equations introduce a nonlocal potential, which is anisotropic for pancake-shaped condensates. We propose to observe this anisotropy via measurement of the condensate aspect ratio. We also derive analytically approximate density profiles from our equations. Both the numerical solutions of our reduced mean-field equations and the analytical density profiles agree well with numerical solutions of the full Gross-Pitaevskii equation while being more efficient to compute.

关键词： Aspect ratio

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Using the feasible set method for rezoning in ALE

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Procedia Computer Science 2010年第1期1卷 1885-1892页

作者： Markus Berndt Milan Kucharik Mikhail J. Shashkov Los Alamos National Laboratory Computational Physics and Methods Group Mail Stop D413 Los Alamos NM 87545 USA Department of Physical Electronics Faculty of Nuclear Sciences and Physical Engineering Czech Technical University in Prague Brehova 7 Praha 1 115 19 Czech Republic Los Alamos National Laboratory Applied Mathematics and Plasma Physics Group Mail Stop B284 Los Alamos NM 87545 USA

One of the steps in the Arbitrary Lagrangian Eulerian (ALE) algorithm is the improvement of the quality of the computational mesh. This step, commonly referred to as rezoning, is essential for maintaining a mesh that does not become invalid during a simulation. In this paper, we present a new robust and computationally efficient 2D mesh relaxation method. This feasible set method is a geometric method for finding the convex polygon that represents the region of coordinates that a vertex in a mesh can occupy while the mesh around it remains valid. After the feasible set has been computed for a vertex in a mesh, a new vertex location can be chosen that lies inside this feasible set. As a result, the mesh after relaxation is guaranteed to be valid. We present an example ALE simulation, that highlights the robustness of the feasible set method when used as a rezoning method in ALE.

关键词： Mesh smoothing Arbitrary Lagrangian Eulerian method ALE Rezoning Feasible set

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