Surface Roughness and Model Scale Influences on Forebody Aerothermodynamics

Abstract

In this study, the surface roughness and model scale influences on forebody aerothermodynamics were examined experimentally. The scaling effect of measured surface pressure and heat flux according to the model scale was observed, and the effect of surface roughness on scaling was considered. The experiment was conducted using a shock tunnel facility with a nominal freestream Mach number of 6. The measured surface pressure and heat flux were compared with the numerical results and theory. Considering the experimental data, a relatively small difference between the models considered with a different roughness was observed in case of pressure. However, a noticeable difference was observed in case of heat flux, in which the cause of the increase in heat flux with the increase in the roughness is thought to be due to the roughness-induced disturbance. The surface heat flux away from the stagnation point is found to be inversely proportional to the square root of model size, a similar trend with that at the stagnation point.