Wind tunnel test research on weapon bay cavity active flow control for acoustic.

An experimental investigation is conducted in a high speed wind tunnel to suppress acoustic resonance. Conventional leading edge mass blowing actuator are used to disturb cavity flow. Detailed static-pressure and fluctuating-pressure measurements are obtained on the cavity walls to determine the effects on cavity flow characteristics. Wind tunnel test based analysis of the suppression of dynamic loads on the walls of a complex weapon bay using leading edge mass blowing is presented. The unique aspect of the concepts discussed here is the very low mass flow rates used to achieve significant suppression. The simulation results are used to gain insight into the mechanism governing the effectiveness of these jets. The PRTB are applied to a deep (L/D = 4. 5) cavity at transonic conditions of Mach 0. 8. The experimental results show excellent agreement with experiments showing an overall reduction of the noise levels of the order of 5 dBs with the control concepts. The primary mechanism of reduction is the break-up of the spanwise coherence in the shear layer into smaller vortical structures thus reducing the shear layer flapping and leading to a smaller imprint on the wall pressures. [ABSTRACT FROM AUTHOR]