A Green's function preconditioner for the steady-state Navier-Stokes equations

Abstract

In this paper we present an efficient method for solving the sparse linear system of equations arising from the discretization of the linearised steady-state Navier-Stokes equations (also known as the Oseen equations). The solver is an iterative method of Krylov subspace type for which we devise a preconditioner based on Green's tensor for the Oseen operator. The preconditioner supersedes existing preconditioners for the Oseen problem in that it exhibits only a mild dependence on the viscosity (inverse Reynolds number) and, most importantly, improved performance with the size of the problem. This comes as no surprise, as preconditioners based on the continuous inverse are expected to perform better on discretizations which approximate well the continuous operator.