Consistency of the explicit roe scheme for low Mach number flows in exterior domains

This chapter presents an analysis of the explicit Roe scheme for the Euler equations of a perfect gas in the low Mach number regime. The CFL condition in explicit schemes is essential in the discrete asymptotic analysis, since it introduces a Strouhal number Str = 1/M into the equations, where M is the reference Mach number. As a result, we can show the consistency of the Roe scheme with the asymptotic Euler equations on the acoustic timescale. Numerical experiments confirm these theoretical results down to a Mach number of M = 10(-7).