Vortrag von Herrn Sergey Grosman


Vortrag von Herrn Sergey Grosman

Am Donnerstag, dem 24.2.2005 um 16.00 Uhr hält

Herr Sergey Grosman (UniBW)

einen Vortrag über das Thema

Hierarchische a-posteriori Fehlerschätzer

Der Vortrag findet im Gebäude 35, Raum 2107 statt.


Singularly perturbed reaction-diffusion problems exhibit in general solutions with anisotropic features, e.g. strong boundary and/or interior layers. This anisotropy is reflected in the discretization by using meshes with anisotropic elements. The quality of the numerical solution rests on the robustness of the a posteriori error estimator with respect to both the perturbation parameters of the problem and the anisotropy of the mesh.

The simplest local error estimator from the implementation point of view is the so-called hierarchical error estimator. The reliability proof is usually based on two prerequisites: the saturation assumption and the strengthened Cauchy-Schwarz inequality. The proofs of these facts are extended in the present work for the case of the singularly perturbed reaction-diffusion equation and of the meshes with anisotropic elements. It is shown that the constants in the corresponding estimates do neither depend on the aspect ratio of the elements, nor on the perturbation parameters. Utilizing the above arguments the concluding reliability proof is provided as well as the efficiency proof of the estimator, both independent of the aspect ratio and perturbation parameters.

A numerical example confirms the theory.

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