Control of cavity flow pressure oscillation through leading edge boundary layer perturbation

Weapons embedding is the key technique to achieve the advanced aerodynamic char-acteristics and stealthy performance for the supersonic cruising fighter.The flow in the weapon cabin is very complex and the sound pressure level of strong noise induced by strong fluctuant pressure is as high as 170dB which may damage the cabin’s structure and the interior facilities,so the cavity noise generation and its corresponding suppression become the hot research topics. This paper presents a brief analysis of the aero acoustic characteristics in a cavity of length-depth ratio (L/D)of 4 with and without leading edge ramps under sub-and transonic conditions (Mach number is 0.6、0.95 and 1.2).The suppression effects of the ramp on aerodynamic noise are dis-cussed by analyzing the sound pressure level distribution on the centerline of the cavity floor and the sound pressure frequency spectrum (SPFS)characteristics at different measurement points. The results show that the leading edge ramps can suppress aerodynamic noise inside the cavity both at the floor and at the sidepiece and it is more effective in SPL reduction in the rear range of the cavity than in the front.The energy peaks of SPFS at some measurement points almost disap-peared with the leading edge ramps which indicate that the flow mechanism of self-sustained os-cillation disappeared.