Convergence analysis of a new multiscale finite element method with the P_0/P_0 element for the incompressible flow

摘要

In this paper, we propose a new multiscale finite element method for the stationary Navier-Stokes problem. This new method for the lowest order finite element pairs P_1/P_0 is based on the multiscale enrichment and derived from the Navier-Stokes problem itself. Therefore, the new multiscale finite element method better reflects the nature of the nonlinear problem. The well-posedness of this new discrete problem is proved under the standard assumption. Meanwhile, convergence of the optimal order in H~1-norm for velocity and L~2-norm for pressure is obtained. Especially, via applying a new dual problem for the incompressible Navier-Stokes problem and some techniques in the process for proof, we establish the convergence of the optimal order in L~2-norm for the velocity. Finally, numerical examples confirm our theory analysis for this new multiscale finite element method and validate the high effectiveness of this new method.