Wall temperature effect on hypersonic vehicle drag

To study the effect of wall temperatures on drag of hypersonic vehicle, experiments are carried in a pulse combustion wind tunnel and a general hypersonic wind tunnel using a typical hypersonic vehicle model. Combined with simulation results, the flow mechanism is analyzed and the differences of the test results in each wind tunnel are investigated. The drag prediction principle of typical hypersonic vehicle is proposed. The validity is verified by the drag prediction results at flight condition. It is shown that the drag differences of the test results at wind tunnels are due to the ratio of wall temperature and inflow static temperature, which has an important effect on the pressure drag and the friction drag of the engine inner channel. When the drag of hypersonic vehicle is predicted, there are three similarity parameters which need to be simulated, i.e., the Mach number, Reynolds number, as well as the ratio of wall temperature to inflow static temperature.