Nonequilibrium Real-gas Effects on Disturbance/bow Shock Interaction in Hypersonic Flow past a Cylinder

The interaction of free-stream disturbances and the bow shock wave in hypersonic ow past a blunt leading edge is an important part of hypersonic boundary layer receptivity to free-stream disturbances. It has been shown that, for a perfect gas, the back and forth interaction and reeection of acoustic waves behind the shock greatly amplify the magnitudes of the disturbance waves. The interaction also generates a wide range of wavelengths for entropy and vorticity waves behind the shock due to the nonuniformity of mean ow over the body. For hypersonic ow over a blunt body, real gas eeects become important because of high gas temperature behind the shock. In this paper , nonequilibrium real gas eeects on the free-stream disturbance/bow shock interaction for hypersonic ow past a cylinder are investigated by numerical simulations and by linear analysis. The freestream disturbances are xed-frequency planar acoustic wave. It was found that the real gas eeects reduce the intensity of the space-time focusing of entropy waves on the wall and introduce new small length scales related to vibrational relaxation to the interaction wave elds.