Head-end secondary flows in solid-propellant rockets due to transverse acoustic waves
The secondary flowfield in the head-end region of solid-propellant rocket motor combustion chamber is derived based on a simplified model. Employing a small perturbation technique, a secondary nonoscillatory perturbation mean flow is generated in a quiescent fluid on an infinite flat plate by the presence of a small amplitude transverse traveling wave motion. Effects of compressibility, variable viscosity, and heat transfer are considered in the study. The firstorder oscillatory flow results in a steady mass transport outside of the viscous boundary layer. The secondary perturbation mean flow is found to be a complex three-dimensional spiral motion. The predicted flowfield in this region gives a qualitative explanation of the mechanism of formation of strong axial vortex filament that has been observed in cylindrical combustion chambers during unstable burning.