A quadrilateral, anisotropic, superconvergent, nonconforming double set parameter element (Q2495814)

The authors present a four-parameter quadrilateral nonconforming finite element with double set parameter (DSP). The element is originated from the nonconforming rotated \(Q_{1}\) element and the bilinear element. The authors prove that this it is an anisotropic and superconvergent nonconforming quadrilateral finite element. Numerical results are also presented.