Experimental Investigation of the Short Isolator with the Ramp Under Asymmetric Incoming Flow

In order to improve a scramjet isolator resistance to anti-pressure capability and reduce its length, an isolator with three kinds of ramps, i.e. a full ramp, a swept ramp and a sweep forward ramp were designed. The ramp was placed on the lower wall in which the boundary layer is thicker than the upper wall. The experiment was conducted in a blow-down supersonic wind tunnel at free stream Mach number of 1.98 under asymmetric incoming flow. Experimental results indicated that the swept ramp’s maximum back-pressure is increased most in the three kinds of ramps. The maximum back-pressure is improved by 9.89 percent in the isolator with a swept ramp which can withstand a maximum backpressure of 3.901 times of free stream static pressure, but the isolator without a ramp could only withstand a maximum back-pressure of 3.55 times of free stream static pressure. Compared to the full ramp and the sweep forward ramp, the maximum back-pressure of the isolator with the swept ramp is enhanced about 1.44 %.The length of the isolator with a swept ramp is reduced by 15 percent at the same back-pressure. The total pressure recovery ratio of the isolator with a swept ramp is improved by 2.3 percent. The total pressure recovery ratio of the isolator with the swept ramp is 0.710, but the baseline isolator’s total pressure recovery ratio is 0.694.