Viscous shock layer at the stagnation point with nonequilibrium air chemistry

Abstract

A finite-difference method and a nonlinear overrelaxation method are investigated for solving the viscous shock layer at the stagnation point of a blunt body. An air gas model is employed with finite reaction rates and accurate thermodynamic and transport properties. For a body with a 1-in. nose radius and at a velocity of 20 kfps, the present results at 100, 150, 200, and 250 kft show that boundary-layer theory with the inviscid edge flow in chemical equilibrium is appropriate for some altitude below 150 kft. When the altitude is 250 kft, the effects of shock slip must be included in the viscous shock-layer solution. For this case, the air is only slightly dissociated and ionized. The present results, with a seven-species air model, are in general agreement with the diatomic air model results of Cheng and Chung.