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Anisotropic Adaptation On Unstructured Grids
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Book Synopsis Anisotropic Adaptation on Unstructured Grids by :
Download or read book Anisotropic Adaptation on Unstructured Grids written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of the present research is to assess the use of grid adaptation to improve Computational Fluid Dynamics calculations. Many issues of the quality discretization of a flow domain are discussed. The representation of the highly directional features in a flow field, such as shocks and boundary layers, forms the focus of the analysis. Anisotropic adaptation, which uses stretched elements to resolve directional features, is more effective than isotropic adaptation. Anisotropic adaptation requires more degrees of freedom from the mesh and demands the use of unstructured grids in the adaptation. The size and orientation of an anisotropic element require a matrix-like local feature indicator. The Hessian, a matrix composed of the second derivatives of an appropriate flow variable, is defined and used as a feature indicator in the adaptation. The Hessian provides a metric that defines the length of an edge and the lengths of all edges are equal in the optimized mesh. The techniques to minimize the differences among edge lengths are discussed and those chosen include node enrichment, node removal, edge swapping and point smoothing. A unified procedure based on the advancing front method is implemented to reconstruct the local connectivity that has been removed in the node removal and edge swapping processes. The results indicate that the mesh in which the edge lengths are equalized is not correct for three major flow features one frequently encounters. The inflections existing near the wall in a boundary layer result in coarse grids there. A "wall" Hessian is defined to replace the second derivatives and give a more appropriate spacing for high Reynolds number flow modeling. Difficulties in the adaptation of discontinuities are addressed. These include the infinite refinement that tries to pull all the points close to the discontinuity and the deviation of the shock from the refinement region because it is too thin. Remedies proposed are to limit the minimum physical edge length and smooth the Hessian such that the refinement encompasses more layers of elements. The strength of a discontinuity is defined and methodology to refine the discontinuity equally is proposed. The invalidity of the Hessian in a free stream is corrected to give a reasonable grid size in that region. It is demonstrated that these suggested modifications improve the overall quality of the adapted mesh as well as the solution. The concepts involved in the extension of the length-based approach to three dimensions are addressed. The difference and difficulties in three-dimensional adaptation are discussed. Barriers exist which prevent the equidistribution of the edge lengths, the goal of the current approach.
Book Synopsis Proceedings of the 17th International Meshing Roundtable by : Rao V. Garimella
Download or read book Proceedings of the 17th International Meshing Roundtable written by Rao V. Garimella and published by Springer Science & Business Media. This book was released on 2008-10-23 with total page 622 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the articles presented at the 17th International Meshing Roundtable (IMR) organized, in part, by Sandia National Laboratories and held October 12-15, 2008. The volume presents recent results of mesh generation and adaptation which has applications to finite element simulation. It introduces theoretical and novel ideas with practical potential.
Book Synopsis Anisotropic Grid Adaptation on Unstructured Meshes by : Guoping Xia
Download or read book Anisotropic Grid Adaptation on Unstructured Meshes written by Guoping Xia and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis 3D Anisotropic Adaptation for External and Turbomachinery Flows on Hybrid Unstructured Grids by : M. Robichaud
Download or read book 3D Anisotropic Adaptation for External and Turbomachinery Flows on Hybrid Unstructured Grids written by M. Robichaud and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Optimesh: Anisotropic Mesh Adaptation with CAD Integrity for Verifiably Accurate CFD Solutions Over Complete Aircraft by : Wagdi G. Habashi
Download or read book Optimesh: Anisotropic Mesh Adaptation with CAD Integrity for Verifiably Accurate CFD Solutions Over Complete Aircraft written by Wagdi G. Habashi and published by . This book was released on 2003 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The code discussed here represents an advanced novel anisotropic mesh adaptation approach for unstructured grids that allows the customization of grids based on a specified error level. Equally important, it maintains the CAD integrity of the given geometry. Perhaps the best showcase of the abilities of this software is the adaptation of unstructured tetrahedral meshes over a complete Airbus 320 and a Boeing 747 with flow-through engine nacelles.
Book Synopsis New Challenges in Grid Generation and Adaptivity for Scientific Computing by : Simona Perotto
Download or read book New Challenges in Grid Generation and Adaptivity for Scientific Computing written by Simona Perotto and published by Springer. This book was released on 2015-04-27 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume collects selected contributions from the “Fourth Tetrahedron Workshop on Grid Generation for Numerical Computations”, which was held in Verbania, Italy in July 2013. The previous editions of this Workshop were hosted by the Weierstrass Institute in Berlin (2005), by INRIA Rocquencourt in Paris (2007), and by Swansea University (2010). This book covers different, though related, aspects of the field: the generation of quality grids for complex three-dimensional geometries; parallel mesh generation algorithms; mesh adaptation, including both theoretical and implementation aspects; grid generation and adaptation on surfaces – all with an interesting mix of numerical analysis, computer science and strongly application-oriented problems.
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781719482219 Total Pages :56 pages Book Rating :4.4/5 (822 download)
Book Synopsis Anisotropic Solution Adaptive Unstructured Grid Generation Using Aflr by : National Aeronautics and Space Administration (NASA)
Download or read book Anisotropic Solution Adaptive Unstructured Grid Generation Using Aflr written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-23 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: An existing volume grid generation procedure, AFLR3, was successfully modified to generate anisotropic tetrahedral elements using a directional metric transformation defined at source nodes. The procedure can be coupled with a solver and an error estimator as part of an overall anisotropic solution adaptation methodology. It is suitable for use with an error estimator based on an adjoint, optimization, sensitivity derivative, or related approach. This offers many advantages, including more efficient point placement along with robust and efficient error estimation. It also serves as a framework for true grid optimization wherein error estimation and computational resources can be used as cost functions to determine the optimal point distribution. Within AFLR3 the metric transformation is implemented using a set of transformation vectors and associated aspect ratios. The modified overall procedure is presented along with details of the anisotropic transformation implementation. Multiple two-and three-dimensional examples are also presented that demonstrate the capability of the modified AFLR procedure to generate anisotropic elements using a set of source nodes with anisotropic transformation metrics. The example cases presented use moderate levels of anisotropy and result in usable element quality. Future testing with various flow solvers and methods for obtaining transformation metric information is needed to determine practical limits and evaluate the efficacy of the overall approach. Marcum, David L. Langley Research Center UNSTRUCTURED GRIDS (MATHEMATICS); GRID GENERATION (MATHEMATICS); ANISOTROPY; ERROR ANALYSIS; COMPUTATIONAL GRIDS; COMPUTATIONAL FLUID DYNAMICS; TETRAHEDRONS; DERIVATION; OPTIMIZATION; ASPECT RATIO; SENSITIVITY
Book Synopsis Anisotropic hp-Mesh Adaptation Methods by : Vít Dolejší
Download or read book Anisotropic hp-Mesh Adaptation Methods written by Vít Dolejší and published by Springer Nature. This book was released on 2022-06-06 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mesh adaptation methods can have a profound impact on the numerical solution of partial differential equations. If devised and implemented properly, adaptation significantly reduces the size of the algebraic systems resulting from the discretization, while ensuring that applicable error tolerances are met. In this monograph, drawing from many years of experience, the authors give a comprehensive presentation of metric-based anisotropic hp-mesh adaptation methods. A large part of this monograph is devoted to the derivation of computable interpolation error estimates on simplicial meshes, which take into account the geometry of mesh elements as well as the anisotropic features of the interpolated function. These estimates are then used for the optimization of corresponding finite element spaces in a variety of settings. Both steady and time dependent problems are treated, as well as goal-oriented adaptation. Practical aspects of implementation are also explored, including several algorithms. Many numerical experiments using the discontinuous Galerkin method are presented to illustrate the performance of the adaptive techniques. This monograph is intended for scientists and researchers, including doctoral and master-level students. Portions of the text can also be used as study material for advanced university lectures concerning a posteriori error analysis and mesh adaptation.
Book Synopsis Mesh Adaptation for Computational Fluid Dynamics, Volume 1 by : Alain Dervieux
Download or read book Mesh Adaptation for Computational Fluid Dynamics, Volume 1 written by Alain Dervieux and published by John Wiley & Sons. This book was released on 2022-08-30 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Simulation technology, and computational fluid dynamics (CFD) in particular, is essential in the search for solutions to the modern challenges faced by humanity. Revolutions in CFD over the last decade include the use of unstructured meshes, permitting the modeling of any 3D geometry. New frontiers point to mesh adaptation, allowing not only seamless meshing (for the engineer) but also simulation certification for safer products and risk prediction. Mesh Adaptation for Computational Dynamics 1 is the first of two volumes and introduces basic methods such as feature-based and multiscale adaptation for steady models. Also covered is the continuous Riemannian metrics formulation which models the optimally adapted mesh problem into a pure partial differential statement. A number of mesh adaptative methods are defined based on a particular feature of the simulation solution. This book will be useful to anybody interested in mesh adaptation pertaining to CFD, especially researchers, teachers and students.
Book Synopsis Mesh Adaptation for Computational Fluid Dynamics, Volume 2 by : Alain Dervieux
Download or read book Mesh Adaptation for Computational Fluid Dynamics, Volume 2 written by Alain Dervieux and published by John Wiley & Sons. This book was released on 2022-08-23 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: Simulation technology, and computational fluid dynamics (CFD) in particular, is essential in the search for solutions to the modern challenges faced by humanity. Revolutions in CFD over the last decade include the use of unstructured meshes, permitting the modeling of any 3D geometry. New frontiers point to mesh adaptation, allowing not only seamless meshing (for the engineer) but also simulation certification for safer products and risk prediction. Mesh Adaptation for Computational Dynamics 2 is the second of two volumes and introduces topics including optimal control formulation, minimizing a goal function, and extending the steady algorithm to unsteady physics. Also covered are multi-rate strategies, steady inviscid flows in aeronautics and an extension to viscous flows. This book will be useful to anybody interested in mesh adaptation pertaining to CFD, especially researchers, teachers and students.
Book Synopsis Anisotropic Mesh Adaptation by : Mahkame Sharbatdar
Download or read book Anisotropic Mesh Adaptation written by Mahkame Sharbatdar and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Unstructured Anisotropic All-quad Mesh Adaptation Based on a Continuous Local Error Model for the Discontinuous Galerkin Method by : Keigan MacLean
Download or read book Unstructured Anisotropic All-quad Mesh Adaptation Based on a Continuous Local Error Model for the Discontinuous Galerkin Method written by Keigan MacLean and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "This thesis will present a method of unstructured anisotropic adaptation for all-quad mesh suitable for use with high-order methods. The overall goal is to minimize the computational cost needed to perform highly accurate Computational Fluid Dynamics (CFD) simulations. With adaptive methods this can be accomplished through modifying the underlying spatial discretization of the domain. Here, this will be tailored to the particular problem at hand through a continuous local error model. In this form, the physical mesh geometry is replaced by the notion of a frame field, allowing us to extend previous ideas from metric-based adaptation methods. This will serve as a means to restate the discrete error minimization problem in order to determine the target element size and shape based on an optimal distribution of degrees of freedom.Furthermore, the goal of most CFD simulations is to measure some particular output of interest (e.g. such as lift or drag). Therefore, extensions to the method will be examined for goal-oriented adaptation. This involves using the adjoint problem solution and dual-weighted residuals to target mesh refinement in areas most crucial to the accuracy of these measurements.Finally, this work will also consider the implementation of a fully unstructured and anisotropic all-quad mesh generator capable of conforming to the aforementioned target elements. Here, the procedure is based on an Lp-CVT energy minimization problem used to determine updated node positions. Overall, this work will combine each of these aspects in order to establish a complete adaptive framework for use in solving high-order problems with the Discontinuous Galerkin method"--
Book Synopsis Two-dimensional, Three-dimensional and Four-dimensional Anisotropic Mesh Adaptation for the Time-continuous Space-time Finite Element Method with Applications to the Incompressible Navier-Stokes Equations by : Pascal Tremblay
Download or read book Two-dimensional, Three-dimensional and Four-dimensional Anisotropic Mesh Adaptation for the Time-continuous Space-time Finite Element Method with Applications to the Incompressible Navier-Stokes Equations written by Pascal Tremblay and published by . This book was released on 2007 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Anisotropic Mesh Adaptation written by and published by . This book was released on 1996 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Unstructured Grid Generation Techniques and Software by :
Download or read book Unstructured Grid Generation Techniques and Software written by and published by . This book was released on 1993 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Proceedings of the 15th International Meshing Roundtable by : Philippe P. Pebay
Download or read book Proceedings of the 15th International Meshing Roundtable written by Philippe P. Pebay and published by Springer Science & Business Media. This book was released on 2007-07-20 with total page 579 pages. Available in PDF, EPUB and Kindle. Book excerpt: The papers in this volume were selected for presentation at the 15th International Meshing Roundtable, held September 17–20, 2006 in Birmingham, Alabama, U.S.A.. The conference was started by Sandia National Laboratories in 1992 as a small meeting of organizations striving to establish a common focus for research and development in the field of mesh generation. Now after 15 consecutive years, the International Meshing Roundtable has become recognized as an international focal point annually attended by researchers and developers from dozens of countries around the world. The 15th International Meshing Roundtable consists of technical presentations from contributed papers, keynote and invited talks, short course presentations, and a poster session and competition. The Program Committee would like to express its appreciation to all who participate to make the IMR a successful and enriching experience. The papers in these proceedings were selected from among 42 submissions by the Program Committee. Based on input from peer reviews, the committee selected these papers for their perceived quality, originality, and appropriateness to the theme of the International Meshing Roundtable. The Program Committee would like to thank all who submitted papers. We would also like to thank the colleagues who provided reviews of the submitted papers. The names of the reviewers are acknowledged in the following pages. As Program Chair, I would like to extend special thanks to the Program Committee and to the Conference Coordinators for their time and effort to make the 15th IMR another outstanding conference.
Book Synopsis Meshing, Geometric Modeling and Numerical Simulation, Volume 2 by : Paul Louis George
Download or read book Meshing, Geometric Modeling and Numerical Simulation, Volume 2 written by Paul Louis George and published by John Wiley & Sons. This book was released on 2019-01-25 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: Triangulations, and more precisely meshes, are at the heart of many problems relating to a wide variety of scientific disciplines, and in particular numerical simulations of all kinds of physical phenomena. In numerical simulations, the functional spaces of approximation used to search for solutions are defined from meshes, and in this sense these meshes play a fundamental role. This strong link between meshes and functional spaces leads us to consider advanced simulation methods in which the meshes are adapted to the behaviors of the underlying physical phenomena. This book presents the basic elements of this vision of meshing. These mesh adaptations are generally governed by a posteriori error estimators representing an increase of the error with respect to a size or metric. Independently of this metric of calculation, compliance with a geometry can also be calculated using a so-called geometric metric. The notion of mesh thus finds its meaning in the metric of its elements.
