Classification of corner vortex shedding in solid rocket motor

A test motor named C1x was numerically simulated by the three-dimensional large eddy simulation (LES) method to study the acoustic-vortex coupling caused by corner vortex shedding. The results show that three-dimensional LES method obtains more accurate result on corner vortex shedding motion and lock-on characteristic than the two-dimensional LES and the axisymmetric LES. Two types of the corner vortex shedding are determined according to whether an acoustic feedback cycle is formed in the chamber. One type of the corner vortex shedding causes the acoustic-vortex formation feedback cycle (named 1st vortex shedding), and the other is dissipated during convecting downstream (named 2nd vortex shedding). Step expansion ratio and aspect ratio upstream and downstream the step of combustion are the important parameters for summarizing the corner vertex shedding type.