Bleed System for Safe Release of Weapons from Combat Aircraft

An idea was carried out on an open cavity having a free stream Mach number of 0.8. The main objective of the present study is to design a passive venting that connects the high pressure region on the rear wall to a low pressure region downstream of the cavity. The baseline condition shows that the cavity flow oscillate with the total amplitude of 155 m. The vortex clipping which is responsible for the self-sustained nature of the cavity flow and the corresponding time history of the pressure on the cavity rear wall is discussed. A cross correlation analysis was carried out between the pressure history at the points on the rear wall of the cavity and the ones on the wall downstream of the cavity. Two points that defines the passive venting were identified based on the rear wall Overall Sound Pressure Level (OASPL) and the minimum time lag computed by cross correlation. The venting is shown to reduce the cavity oscillations and the rear wall pressure is shown to reach a steady state value which is desired in the perception of low cavity noise that can be used to reduce the structural loads and the acoustic loads on electronic components kept near the cavity.