Research on cavity collapse characteristics during high-speed water-exit of the supercavitating projectile

Abstract

During high-speed water-exit of the supercavitating projectile, the cavity interacts with the free surface and collapses, with instantaneous high collapse pressure impacting on the projectile. In order to study the cavity collapse characteristics during high-speed water-exit of the supercavitating projectile, the numerical study based on the Reynolds-averaged equation and the volume of fluid multiphase flow model is conducted in this paper. The results show that the cavity near the free surface will gradually become larger with the movement of the projectile during water-exit of the supercavitating projectile. The existence of attitude angles will cause the asymmetry of cavity to collapse. The cavity on the upstream side will first collapse and generate collapse pressure, while the cavity on the downstream side will collapse later but generate higher collapse pressure. The asymmetry of the cavity collapse becomes stronger with the increasing attitude angles. The time interval of the collapse pressure on the downstream and upstream sides of the projectile becomes shorter close to the projectile tail.