Numerical Simulations Based Evidence of Impingement Free Sound Production During Vortex-Nozzle Interaction in Solid Rocket Motors

Abstract

Dedicated numerical simulations of vortex-nozzle interaction indirect noise in solid rocket motors (SRMs) are presented. It is assumed that the flow in the nozzle and hence the sound radiation is not significantly influenced by the global acoustic oscillation of a SRM. Therefore, the study is limited to the acoustic response of a semi-infinite pipe terminated by a choked nozzle. The nozzle considered here is placed flush in a wall forming a right angle to the walls of the combustion chamber. The study focuses on where sound is produced due to vortex-nozzle interaction. The presented results indicate that sound is produced when the vortex is on its approach to the nozzle, rather than by impingement of the vortex on the nozzle walls.