New Criterion for First Grid Spacing off Wall Surface in Hypersonic Flow

摘要

In hypersonic flow calculations, the grid spacing next to the wall surface is one of the key factors in the prediction of surface heat transfer. The main tool to build the chemical nonequilibrium mathematical model is the system of the axisymmetric Navier-Stokes equations, the thermodynamic relations, and the chemical reaction model. The axisymmetric solver is developed by the implicit finite volume schemes and is validated by comparing the computational results with that in the literature. Combining the Kemp-Riddell empirical formula with the numerical results, a new criterion for the first grid spacing next to the wall surface is proposed by considering three factors such as the freestream density, the velocity, and the radius of a blunt nose. It can effectively predict the surface heat flux at the stagnation point.