Computation of hypersonic flow over a reentry capsule with roughness induced transition

The heat flux on the heat-shield and backshell of the Apollo capsule like test models with the roughness in the higher enthalpy conditions were computed using RANS and our developed high order code. Aeroheating measurements with the roughness induced transition on the heat-shield of an Apollo capsule model and on the backshell of a HTV-R test model which was a manned space capsule were performed in the higher enthalpy conditions by the free-piston shock HIEST in JAXA. Measured data set indicate that heat flux on the heat-shield of the Apollo capsule model was 1.5-2 times larger than the heat flux in laminar flow. On the other hand, the heat flux on the backshell of HTV-R became 2-4 times larger. In order to estimate accurate heat flux such turbulent flow, a high order CFD code in hypersonic flow was developed. On the heat-shield, RANS overestimated the measured data on the leeward surface especially in the high enthalpy conditions. This trend is not bad for the safe design of the TPS. On the other hand, RANS underestimates the peak heating of measured data on the backshell. The peak heat flux calculated by the high order code and fine mesh could obtain significant agreement with the measured peak heat flux.