Analysis of Injecting Wall Inclination on Segmented Solid Rocket Motor Instability

The influence of αα solid propellant inclination angle was analyzed through small-scale setup simulations. Two injected blocks separated by thermal protection reproduced the main geometric solid rocket motor features, and a dual phenomenon driving interactions between the shear layer and injecting wall vortex-shedding phenomena was clearly identified at any inclination angle. A threshold angle level was also pinpointed, and it literally controls either the decrease of oscillation levels for small angles or the increase of the coupling energy involved. Under similar dynamic conditions, a decreasing factor of two was observed between α=0α=0 and -1.5deg-1.5deg, whereas an even higher amplification factor was noted for α=-2degα=-2deg. Correlation coefficients and phase-averaged analysis have allowed the authors to clearly explain these opposed trends by depicting the wall and shear-layer interactions along the chamber. [PUBLISHER ABSTRACT]