Hybridized SLAU2-HLLI Riemann Solver for Magnetohydrodynamics Simulations

摘要

SLAU2 (Kitamura and Shima JCP 2013), one of AUSM-type solvers, has been extended to magnetohydrodynamicsrn(MHD). At higher Mach numbers, however, SLAU2 was found not to function well for some MHD Riemann problems.rnThe HLLI Riemann solver (Dumbser and Balsara JCP 2016) has a dissipation which makes it unsuitable for low Machrnnumber flows. However, it has very favorable performance for higher Mach number MHD flows. Since the twornfamilies of Riemann solvers both perform very well over a range of intermediate Mach numbers, the best way tornbenefit from the mutually complementary strengths of both these Riemann solvers is to hybridize between them. Thernresult is an all-speed Riemann solver for MHD. We, therefore, document a hybridized SLAU2-HLLI Riemann solver.rnThe hybrid Riemann solver suppresses the oscillations that appeared in single solver solutions, and it also preservesrncontact discontinuities, as well as Alfven waves, very well.