Impact of triangle shapes using high-order discretizations and direct mesh adaptation for output error

Thesis (S.M.)--Massachusetts Institute of Technology, Computation for Design and Optimization Program, 2009. === This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. === Cataloged from student submitted PDF...

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Main Author: Sun, Huafei
Other Authors: David L. Darmofal.
Format: Others
Language:English
Published: Massachusetts Institute of Technology 2010
Subjects:
Online Access:http://hdl.handle.net/1721.1/54215
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spelling ndltd-MIT-oai-dspace.mit.edu-1721.1-542152019-05-02T16:15:52Z Impact of triangle shapes using high-order discretizations and direct mesh adaptation for output error Sun, Huafei David L. Darmofal. Massachusetts Institute of Technology. Computation for Design and Optimization Program. Massachusetts Institute of Technology. Computation for Design and Optimization Program. Computation for Design and Optimization Program. Thesis (S.M.)--Massachusetts Institute of Technology, Computation for Design and Optimization Program, 2009. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. Cataloged from student submitted PDF version of thesis. Includes bibliographical references (p. 95-101). The impact of triangle shapes, including angle sizes and aspect ratios, on accuracy and stiffness is investigated for simulations of highly anisotropic problems. The results indicate that for high-order discretizations, large angles do not have an adverse impact on solution accuracy. However, a correct aspect ratio is critical for accuracy for both linear and high-order discretizations. In addition, large angles are not problematic for the conditioning of the linear systems arising from discretization. They can be overcome through small increases in preconditioning costs. A direct adaptation scheme that controls the output error via mesh operations and mesh smoothing is also developed. The decision of mesh operations is solely based on output error distribution without any a priori assumption on error convergence rate. Anisotropy is introduced by evaluating the error changes due to potential edge split, and thus the anisotropies of both primal and dual solutions are taken into account. This scheme is demonstrated to produce grids with fewer degrees of freedom for a specified error level than the existing metric-based approach. by Huafei Sun. S.M. 2010-04-26T19:19:26Z 2010-04-26T19:19:26Z 2009 2009 Thesis http://hdl.handle.net/1721.1/54215 587498193 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 101 p. application/pdf Massachusetts Institute of Technology
collection NDLTD
language English
format Others
sources NDLTD
topic Computation for Design and Optimization Program.
spellingShingle Computation for Design and Optimization Program.
Sun, Huafei
Impact of triangle shapes using high-order discretizations and direct mesh adaptation for output error
description Thesis (S.M.)--Massachusetts Institute of Technology, Computation for Design and Optimization Program, 2009. === This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. === Cataloged from student submitted PDF version of thesis. === Includes bibliographical references (p. 95-101). === The impact of triangle shapes, including angle sizes and aspect ratios, on accuracy and stiffness is investigated for simulations of highly anisotropic problems. The results indicate that for high-order discretizations, large angles do not have an adverse impact on solution accuracy. However, a correct aspect ratio is critical for accuracy for both linear and high-order discretizations. In addition, large angles are not problematic for the conditioning of the linear systems arising from discretization. They can be overcome through small increases in preconditioning costs. A direct adaptation scheme that controls the output error via mesh operations and mesh smoothing is also developed. The decision of mesh operations is solely based on output error distribution without any a priori assumption on error convergence rate. Anisotropy is introduced by evaluating the error changes due to potential edge split, and thus the anisotropies of both primal and dual solutions are taken into account. This scheme is demonstrated to produce grids with fewer degrees of freedom for a specified error level than the existing metric-based approach. === by Huafei Sun. === S.M.
author2 David L. Darmofal.
author_facet David L. Darmofal.
Sun, Huafei
author Sun, Huafei
author_sort Sun, Huafei
title Impact of triangle shapes using high-order discretizations and direct mesh adaptation for output error
title_short Impact of triangle shapes using high-order discretizations and direct mesh adaptation for output error
title_full Impact of triangle shapes using high-order discretizations and direct mesh adaptation for output error
title_fullStr Impact of triangle shapes using high-order discretizations and direct mesh adaptation for output error
title_full_unstemmed Impact of triangle shapes using high-order discretizations and direct mesh adaptation for output error
title_sort impact of triangle shapes using high-order discretizations and direct mesh adaptation for output error
publisher Massachusetts Institute of Technology
publishDate 2010
url http://hdl.handle.net/1721.1/54215
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