The Role of Vortices in Side Jet/Blunt Body Interaction at Hypersonic Speed

Abstract

A numerical investigation was carried out for a blunt body with a circular sonic air jet normally injected into a hypersonic flow from the body surface, where the angle of attack was changed up to 40◦. Computed results were compared with the experimental data collected using the shock tunnel of Nagoya University. The aerodynamic interaction due to the jet creates complicated flow fields, which are rather difficult to analyze alone experimentally. The computed results show good agreement with the experimental data with regard to surface pressure distribution and schlieren visualization. It was found that at rather low angles of attack, two vortices, i.e., a separation vortex and a horseshoe vortex, are formed inside the separated boundary layer upstream of the jet. The location of these vortices corresponds to low-pressure regions in the pressure distribution. On the other hand, at a rather high angle of attack, the interaction produces a complex flow field, where vortices have little influence on the pressure distribution. Finally the jet interaction was found to enhance the jet reaction forces by about 35% - 45 % on the body surface, the value of which is close to the experimental data.