Effect of submerged nozzle on pressure oscillation in chamber

Pressure oscillation in combustion chamber could induce the unstable operation of motors or missiles. Nozzle, as a main part of motor, possesses great influence on pressure oscillation. The linear relationship between the pressure oscillation amplitude and the volume of cavity induced by submerged nozzle is validated in this paper using large eddy simulations. The effect of cavity volume on pressure oscillation amplitude is found to be larger than that of the cavity inlet geometry. The vortex-acoustic interaction is examined. The impingement of vortex on submerged nozzle serves as one of most important parts in vortex-acoustic interaction. The conclusion can be used as a reference for design of submerged nozzle of large solid rocket motor.