Assessing the Effects of Internal Blockage on Cavity Aeroacoustics

Cavity flow is well-studied for empty geometries, but the effects of adding internal blockage is largely unknown. This study uses computational fluid dynamics to simulate a rectangular cavity, increasing the volume blockage ratio from empty (0%) to four spherocylinders (20.7%) at Mach 0.95. Grid independence studies are performed for the spherocylinder and cavity grids. Results confirm Rossiter’s equation accurately predicts full-scale cavity modal frequencies. Increasing volume blockage ratio generally reduces sound pressure level and overall sound pressure level. However, there is one configuration that increases sound pressure level and overall sound pressure level, the two spherocylinders horizontal configuration. This configuration amplifies the dominant Rossiter mode, and has a significant increase in overall sound pressure level compared to the baseline empty cavity. This highlights that spatial configuration, not just volume-blockage-ratio, affects acoustic behavior.