Publication Details

Averaging of gradient in the space of linear triangular and bilinear rectangular finite elements

DALÍK, J.; VALENTA, V. Averaging of gradient in the space of linear triangular and bilinear rectangular finite elements. CENT EUR J MATH, 2013, vol. 4, no. 11, p. 597-608. ISSN: 1895-1074.
Czech title
Averaging of gradient in the space of linear triangular and bilinear rectangular finite elements
Type
journal article
Language
English
Authors
Dalík Josef, doc. RNDr., CSc.
Valenta Václav, Ing., Ph.D.
Keywords

A posteriori error estimator; Adaptive solution of elliptic differential problems in 2D; Averaging partial derivatives; Linear triangular and bilinear rectangular finite element; Nonobtuse regular triangulation

Abstract

An averaging method for the second-order approximation of the values of the gradient of an arbitrary smooth function u = u(x1, x2) at the vertices of a regular triangulation Th composed both of rectangles and triangles is presented. The method assumes that only the interpolant \Pi_h[u] of u in the finite element space of the linear triangular and bilinear rectangular finite elements from Th is known. A complete analysis of this method is an extension of the complete analysis concerning the finite element spaces of linear triangular elements from [Dalík J., Averaging of directional derivatives in vertices of nonobtuse regular triangulations, Numer. Math., 2010, 116(4), 619-644]. The second-order approximation of the gradient is extended from the vertices to the whole domain and applied to the a posteriori error estimates of the finite element solutions of the planar elliptic boundary-value problems of second order. Numerical illustrations of the accuracy of the averaging method and of the quality of the a posteriori error estimates are also presented.

Published
2013
Pages
597–608
Journal
CENT EUR J MATH, vol. 4, no. 11, ISSN 1895-1074
Publisher
VERSITA
Place
Velká Británie
BibTeX
@article{BUT98047,
  author="Josef {Dalík} and Václav {Valenta}",
  title="Averaging of gradient in the space of linear triangular and bilinear rectangular finite elements",
  journal="CENT EUR J MATH",
  year="2013",
  volume="4",
  number="11",
  pages="597--608",
  issn="1895-1074"
}
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