Attached flow formed by opposing jet in hyper/supersonic flow

Abstract

In current paper, a numerical study by ANSYS FLUENT software has been carried out on the opposing jet in hyper/supersonic flow. In incoming Mach number 6, flow fields around two head-shape models, namely a hemisphere-cylinder and a cone-cylinder, are calculated, respectively. Air and helium of different temperatures as the injection gases were injected through the sonic nozzle at the nose of the model. In order to track the motion of the opposing jet, we employ the species transport model together with the axisymmetric Navier–Stokes equations as the physical model. And find, due to the effect of the bow shock on the opposing jet, the opposing jet flows back and form an attached flow instead of the incoming high temperature air tightly around the model surface, which effectively achieve the wall heat reduction. Moreover, the higher the incoming Mach number, the more significant the percentage reduction of the wall heat transfer rate is. Helium injection has more advantageous than air injection at lower total pressure ratios. The position and size of the recirculation vortex formed by the opposing-jet attached flow have the direct relationship with the fluctuation range of wall characteristic parameters. The smaller the ratio of the model geometric curvature and recirculation size, the smaller the fluctuation amplitudes of wall characteristic parameters are. By adjusting the injection gaseous parameters, it is hopeful to control the near-wall flow features and the aircraft head-shape conversions.