Investigation of single expansion ramp nozzle

The experimental investigation of a Single Expansion Ramp Nozzle (SERN) in the condition of transonic flight was presented.A large flow separation was observed in the basic model SERN 1 without second flow injection. The thrust coefficient C fx of model SERN 1 is of low as to 0.29～0.58. With second flow injection into the expansion surface the separation region was greatly reduced while the thrust coefficient increased up to around 0.97. The optimized relative height of second flow throat A t2 = A t2 / A t1 was about 0.25 in the experimental situation.