Utilization of embedded surface compliance for suppression of deep cavity flow noise

Abstract

Cavity noise suppression is one of the extensively debated aeroacoustic research problem due to its application over the wide range of mechanical systems. This study presents a scheme of embedding surface compliance in form of elastic panels on cavity walls as a mean to achieve significant tonal noise reduction. A deep cavity of aspect ratio D/L = 0.4 operating at Mach number 0.09 is considered. Using the Direct Aeroacoustic Simulation, the rigid cavity case is investigated to uncover the underlying physical processes driving the aeroacoustic coupling phenomenon between the shear layer and the cavity mode. The analysis suggests that each cavity wall supports a certain coupling associated activity and therefore provides a platform to modify the shear layer – cavity mode interaction in a tacit way through the well-designed positioning of elastic panels. The accordantly mounted elastic panels are then excited with the flow perturbation energy to significantly reduce the pressure fluctuations magnitude of the cavity mode which strongly affects its synchronization with shear layer and hence presents the possibility of significant noise reduction.