A posteriori L2-error estimates for the nonconforming P1P0-finite element discretization of the Stokes equations

This paper focusses on a residual-based a posteriori error estimator for the L2-error of the velocity for the nonconforming P1P0-finite element discretization of the Stokes equations. We derive an a posteriori error estimator which yields a local lower as well as a global upper bound on the error. Numerical tests demonstrate the efficiency of the global error estimator and give a comparison with respect to the adaptive grid refinement to an a posteriori error estimator in the discrete energy norm proposed by Dari et al. (1995).