TY - JOUR T1 - Polynomial Preserving Gradient Recovery and a Posteriori Estimate for Bilinear Element on Irregular Quadrilaterals AU - Zhang , Zhimin JO - International Journal of Numerical Analysis and Modeling VL - 1 SP - 1 EP - 24 PY - 2004 DA - 2004/01 SN - 1 DO - http://doi.org/10.4208/ijnam.OA-2004-1101 UR - https://global-sci.org/intro/article_detail/ijnam/963.html KW - Finite element method, quadrilateral mesh, gradient recovery, superconvergence, a posteriori error estimate. AB -

A polynomial preserving gradient recovery method is proposed and analyzed for bilinear element under quadrilateral meshes. It has been proven that the recovered gradient converges at a rate $O(h^{1+\rho})$ for $\rho = min(\alpha, 1)$, when the mesh is distorted $O(h^{1+\alpha})$ ($\alpha > 0$) from a regular one. Consequently, the a posteriori error estimator based on the recovered gradient is asymptotically exact.