Experiment of influence of the nozzle pressure ratio on the interaction between the external flow and nozzle flow of hypersonic aerocraft

To find out the effect of nozzle plume on aerocraft aerodynamic performance, a pressure measurement experimental study on different nozzle pressure ratios (NPR) of nozzle plume was carried out at a freestream Mach number of 50 and 60 in the 05m hypersonic wind tunnel of China Aerodynamics Research and Development Center (CARDC).The structure of the nozzle plume interaction area was obtained by using schlieren photography. The result showed obvious different pressure distribution of aerocraft afterbody area at a high NPR. When the NPR was high, the nozzle plume interaction area became bigger with a higher pressure. The schlieren pictures also showed that cross interaction shocks became stronger and the extending of the shear layer tended to be more obvious. Interaction area has affected the pressure distribution of the wings, which would affect the control ability of the aerocraft.