TY - JOUR T1 - Superconvergence Analysis of Low Order Nonconforming Mixed Finite Element Methods for Time-Dependent Navier-Stokes Equations AU - Yang , Huaijun AU - Shi , Dongyang AU - Liu , Qian JO - Journal of Computational Mathematics VL - 1 SP - 63 EP - 80 PY - 2020 DA - 2020/09 SN - 39 DO - http://doi.org/10.4208/jcm.1907-m2018-0263 UR - https://global-sci.org/intro/article_detail/jcm/18278.html KW - Navier-Stokes equations, Nonconforming MFEM, Supercloseness and superconvergence. AB -

In this paper, the superconvergence properties of the time-dependent Navier-Stokes equations are investigated by a low order nonconforming mixed finite element method (MFEM). In terms of the integral identity technique, the superclose error estimates for both the velocity in broken $H^1$-norm and the pressure in $L^2$-norm are first obtained, which play a key role to bound the numerical solution in $L^{\infty}$-norm. Then the corresponding global superconvergence results are derived through a suitable interpolation postprocessing approach. Finally, some numerical results are provided to demonstrate the theoretical analysis.