Experimental investigation of pneumatic characteristics for S-shaped inlet in missiles

Experimental investigation of an S-shaped inlet was made in this paper.The results show that: 1) When the yaw angle is constant and the attack angle changes from negative to positive,the total pressure recovery increases at first and then keeps almost constant,while the distortion coefficient drops at first and then rises a little.2) When the attack angle is constant and the yaw angle increases,the total pressure recovery and distortion coefficient increase at first and then decline.3) Under the combination of high incidence and yaw,the total pressure recovery is low and the distortion is high,but the performance will be better if the yaw angle increases farther.4) At the matching point of the inlet and engine,the power spectrum of the flow at the exit is like white noise and not sensitive to the variation of attitude angle and free stream Mach number.5) When the engine is running under small mass flow,the inlet model surge occurs,the frequency of surge is 150Hz.