Effect of Submerged Vortex Generators on Shock-Induced Separation in Transonic Flow

摘要

The effect of a tetrahedral vortex generator on the shock-induced boundary-layer separation has been investigated experimentally at a nominal Mach number of 1.4. The unit Reynolds number was 16 x 10~6 per meter. Two pairs of vortex generators with different heights have been used to control the shock/boundary-layer interaction. Each pair of vertex generators has been placed upstream of the shock location at a fixed distance of 130 mm, which corresponds to 18 times the boundary thickness. Measurements consist of mean boundary-layer profile and streamwise distribution of wall static pressure and Preston pressure. Experimental results suggests that both tetrahedral vortex generators influence and reduce the extent of boundary-layer separation as compared with the baseline configuration, in which no tetrahedral vortex generators were present. Experiments also revealed that the tetrahedral vortex generator with a height of 0.76 did not produce further reduction in the extent of separation region as compared with the smaller tetrahedral vortex generator with a height of 0.46. The experiments confirm that a thicker vortex generator produces more displacement thickness at the expense of a thicker boundary layer and a lower Preston pressure. In both cases, the shape factor of the boundary layer at the location of shock wave showed a decrease of about 46 % as compared with the baseline value.