Vorticoacoustic Stability of Solid Rocket Motors: A Numerical Study

Abstract

This work presents highly resolved Navier–Stokes simulations in a cylindrical solid rocket motor. The study focuses on the vorticoacoustic interactions and their role on motor stability. This paper proposes comparisons between simulations and available theories on unsteady axial velocity but also radial velocity, pressure, temperature, and entropy. Overall, the agreement is excellent except for pressure, which is found to be purely acoustic in simulations (i.e., no vortical pressure). The role of radial velocity is further investigated because it gives rise to the rotational correction term in stability integrals. This paper shows that this term strongly depends on the definition of the propellant admittance, and it can actually be viewed as a part of the classical propellant pressure-coupled response. This study has also estimated damping terms directly by studying the decay of pressure perturbations in simulations and has compared them to classical stability integrals from theory. In keeping with the aforementioned results, the agreement is much better when rotational correction and vortical pressure terms are dropped.