Accuracy improvements and investigations of a compressible second order finite volume code towards the incompressible limit

Abstract

The accuracy of many existing finite volume codes, originally implemented to simulate compressible flows in the transonic or supersonic regime, often degrades as the onflow Mach number is small and tends to zero. The problem is that at low Mach number the Roe scheme or a similar formulated artificial viscosity scheme which is close to a Roe scheme present an excess of artificial viscosity which causes the loss of accuracy. The reason is that at low Mach number the stabilization terms are not of the same order as the flux terms because the wave speeds are of different magnitudes. It is the goal of this talk to present a new methodology to deal with low Mach number flows in a compressible code.