Second-order convergence of the linearly extrapolated Crank–Nicolson method for the Navier–Stokes equations with H1 initial data

Abstract

This article concerns the numerical approximation of the two-dimensional nonstationary Navier–Stokes equations with H1 initial data. By utilizing special locally refined temporal stepsizes, we prove that the linearly extrapolated Crank–Nicolson scheme, with the usual stabilized Taylor–Hood finite element method in space, can achieve second-order convergence in time and space. Numerical examples are provided to support the theoretical analysis.