Experimental and numerical study of the water entry of projectiles at high oblique entry speed

摘要

The water entry of cylindrical projectiles at high oblique speed has been investigated experimentally and numerically. Projectiles with three types of noses and different lengths are tested. The projectiles are lunched at different angles, and the development of supercavities are recorded using high-speed camera. During the water entry, deflections occur due to the deviation of the initial velocity and/or the hydrodynamic impact force. The evolution of the supercavities of projectile without deviation is observed. It is found that the collapse of cavity and the generation of new cavity occur alternatively. The motion and the evolution of supercavities at the initial stage of the water entry are simulated through computational fluid dynamics, the typical pressure distributions have been analysed. The drag coefficients are dominated by the nose shape.