An Improved HLLE Method for Hypersonic Viscous Flows

Dissipation mechanisms of Godunov-type schemes are presented in the framework of unified representation. We first examined the causes of inaccuracy at the contact discontinuity and the dissipation mechanism in the numerical mass flux of the HLLEM scheme. Through a linear perturbation analysis on the oddeven decoupling problem, we discuss necessary conditions for designing a shock stable scheme. The curing methods for each specified problem are also presented. A new improved HLLE(HLLE+) scheme is proposed and analyzed on its dissipation mechanism. The diffusivity of the Godunov-type schemes is examined by computing two-dimensional hypersonic viscous flow. It is shown that the present method can accurately predict the surface heating rates without grid dependency.