An Oseen-Type Post-Processed Finite Element Method Based on a Subgrid Model for the Time-Dependent Navier–Stokes Equations

Abstract

An Oseen-type post-processed mixed finite element method based on a subgrid model is presented for the simulation of time-dependent incompressible Navier–Stokes equations. This method first solves a subgrid stabilized nonlinear Navier–Stokes system on a mesh of size [Formula: see text] to obtain an approximate solution pair [Formula: see text] at the given final time [Formula: see text], and then post-processes the solution [Formula: see text] by solving a stabilized Oseen problem on a finer mesh or in higher-order finite element spaces. We prove stability of the stabilized method, derive error estimates for the post-processed solutions, give some numerical results to verify the theoretical predictions and demonstrate the effectiveness of the proposed method.