Study on Aerodynamic Characteristics of a High Enthalpy Flow around a Blunt-nosed Body

Aerodynamic characteristics of high enthalpy flows around a blunt-nosed cone model have been investigated by both the experiment using a large free-piston driven shock tunnel HIEST and CFD. The reduction of the drag force as the increase of the freestream total enthalpy was observed in the experiments using a large nose-radius model. However, CFD has not been successful in reproducing the CD reduction. The over-estimation of the pressure in the supersonic expanding flow region was one of the issues for CFD. In the present paper, influences of the T-V relaxation time model and the recombination rate model on the aerodynamic characteristics of the cone model were examined. The MW model, which gives the longer T-V relaxation time than the MW-P model, predicted lower CD than the MW-P model although the difference in the CD was within 1%.