Pressure oscillation in solid rocket motors: A discrete convolution approach

This paper addresses the challenge of multi-factor influences on the evolution of pressure oscillations within the combustion chamber of a solid rocket motor. A combustion response treatment method based on discrete convolution is incorporated into the flow field simulation, successfully reproducing the growth of pressure oscillations observed in a ground firing test of a specific motor. Using this method, the stability differences among various oscillation modes, the relationship between combustion response characteristics and pressure oscillation evolution, and the effect of combustion chamber geometry variations on the linear stability of the motor are systematically investigated. The results indicate that higher-order oscillations generally exhibit better stability due to stronger damping, and that a stronger propellant combustion response characteristic leads to poorer linear stability of the motor. Moreover, variations in the combustion chamber geometry simultaneously affect both gain and damping, thereby altering the linear stability trend of the motor. By adjusting the cavity structure, it is possible to suppress all major oscillation modes concurrently, providing a reference for structural optimization and design improvement.