A Theoretical Approach of Thrust Oscillations in S...

Abstract

Solid rocket motors present thrust oscillations at the end of their firings. These oscillations are due to flow instabilities which cause pressure fluctuations. Several possible sources of instabilities have been identified. Among them, the hydrodynamic instabilities of the main flow is believed to play a major role. However, the first hydrodynamic stability studies, based on a classical linear stability analysis, led to a model which is not consistent. Thus, the linear stability of the mean flow has been revisited thanks to a more general approach. The results are compared to measurements coming from cold-gas and reduced scale live motors set-ups. The obtained excellent agreements (in both cases) lead to significant changes in the understanding of the thrust oscillations arising. * The two main ARIANE 5 propellant grains are conical