Abstract: An experimental investigation of a submerged inlet on a plane surface was conducted at free stream Mach numbers from 0.6 to 0.8; angles of attack from -4° to 6°; and yaws from 0° to 4°. The static pressure coefficient distributions along the walls, total pressure recovery contours at the outlet of the inlet, power spectral density (PSD) of the static pressure at the entrance and the total pressure at the exit were obtained in the test. Results indicate: (1) The static pressure coefficient distributions along the walls show that the flow around the fore lip first accelerates, and then decelerates, and the value of the static pressure on the top surface is higher than that on the bottom surface all along when the flow enters the duct. (2) The submerged inlet can work with high performance and stable margin in a wide range of mass flow, free stream Mach number, angle of attack and yaw. (3) The PSD of the total pressure at the engine face generally demonstrate the characteristics of white noise, which is beneficial to inletengine compatibility.

Key words: aerospace propulsion system, submerged inlet, flow characteristics, secondary flow, power spectral density