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A posteriori error estimation for

anisotropic tetrahedral and triangular finite element meshes

Gerd Kunert

ISBN 978-3-89722-180-2
136 pages, year of publication: 1999
price: 40.00 €

Dissertation an der der Fakultät Mathematik der TU Chemnitz

Many physical problems lead to boundary value problems for partial differential equations, which can be solved with the finite element method. In order to construct adaptive solution algorithms or to measure the error one aims at reliable a posteriori error estimators. Many such estimators are known, as well as their theoretical foundation.

Some boundary value problems yield so-called anisotropic solutions (e.g. with boundary layers). Then anisotropic finite element meshes can be advantageous. However, the common error estimators for isotropic meshes fail when applied to anisotropic meshes, or they were not investigated yet.

For rectangular or cuboidal anisotropic meshes a modified error estimator had already been derived. In this paper error estimators for anisotropic tetrahedral or triangular meshes are considered. Such meshes offer a greater geometrical flexibility.

For the Poisson equation we introduce a residual error estimator, an estimator based on a local problem, several Zienkiewicz-Zhu estimators, and an L 2 error estimator, respectively. A corresponding mathematical theory is given. For a singularly perturbed reaction-diffusion equation a residual error estimator is derived as well. The numerical examples demonstrate that reliable and efficient error estimation is possible on anisotropic meshes.

The analysis basically relies on two important tools, namely anisotropic interpolation error estimates and the so-called bubble functions. Moreover, the correspondence of an anisotropic mesh with an anisotropic solution plays a vital role.

Keywords:

finite elements, anisotropic mesh, tetrahedral mesh, triangular mesh, Poisson equation, singularly perturbed reaction-diffusion equation, anisotropic a posteriori error estimate, anisotropic interpolation error estimate

AMS:

65N30, 65N15, 35B25


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