Effects of freestream nonequilibrium on convective heat transfer to a blunt body

The axisymmetric Navier-Stokes equations are solved numerically for nonequilibrium airflows over a hemisphere for two sets of conditions. One set corresponds to a wind-tunnel test flow where the freestream is vibrationally excited and dissociated air, and the other corresponds to hypersonic free flight where the freestream is air at atmospheric conditions, Relevant similitude parameters are partially duplicated in the computations as in the wind-tunnel testing of convective heating. A nonequilibrium formulation with a three-temperature thermochemical model has been employed to simulate vibrationally excited and partially dissociated nonequilibrium airflow, Finite catalytic boundary conditions at the surface are implemented, Computations are carried out at enthalpies of 7.2 and 25 MJ/kg, for surface pressures of 0.017 and 0.076 atm, respectively, Computed stagnation point heat transfer is compared with the classical results of Fay and Riddell, and Goulard. The computed results show that successful testing of surface heat transfer in a high-enthalpy tunnel is possible with partial duplication of similitude variables.