CONSTRAINED QUADRILATERAL NONCONFORMING ROTATED Q1 ELEMENT

• 来源期刊: 计算数学（英文版）
• 关键词: Constrained Nonconforming Rotated Q1 element Superconvergence Postprocess.
• 年，卷（期）: 2005,（6）
• 页码范围: 561-586
• 页数: 26页
• 语种: 英文

摘要

In this paper, we define a new nonconforming quadrilateral finite element based on the nonconforming rotated Q1 element by enforcing a constraint on each element, which has only three degrees of freedom. We investigate the consistency, approximation, superclose property, discrete Green's function and superconvergence of this element. Moreover, we propose a new postprocessing technique and apply it to this element. It is proved that the postprocessed discrete solution is superconvergent under a mild assumption on the mesh.