An experimental survey on the effect of Tetrahedral Vortex Generator on Shock Induced Boundary Layer Separation at Mach1.4

The effect of a Tetrahedral Vortex Generator on the shock induced separation is investigated experimentally in Whitehead Lab. A pair of this model of vortex generator is used to contract the shock wave/ boundary later interaction. It is located at 13 cm upstream of shock location, which is 18 times of boundary layer thickness at the position of the model. The wind tunnel is a diverging-converging nozzle with the inlet Mach Number 1.4. It has a working section of 122 cm length, 12.6 cm width and a varied height from 12 to 18.5 cm. The location of the shock wave can be controlled by an adjustable choke mechanism. Measurements consist of mean boundary layer profile, static pressure and Preston pressure at several streamwise locations. The model looks promising as a reliable technique for attenuation of separation. It can be seen that at the zone of separation, there is an area where total pressure is less than static pressure. This implies that small separation still exists. This model achieves the goal of suppressing the separation. The Schlieren visualization proved that extent of lambda is shorter than baseline. Shape factor for this type of vortex generator shows a very good performance in comparison with the baselineshape factor, as it decreased by up to 46% at the shock location.