Research on the process of vertical water entry experiment of truncated cone-shaped projectile

In order to study the influence of the diameter and velocity of the truncated head on the cavitation and motion characteristics of the projectile when it enters the water vertically, based on the high-speed camera method, the contrast experiment of the different diameter of the truncated head is carried out, and the influence law of the diameter and velocity of the head on the cavitation and motion velocity is obtained. The experimental results show that the velocity change law of the projectile in the deep closed state is basically the same, and the velocity change law in the process of turning the surface closed state begins to change; With the increase of the initial velocity of the projectile, the earlier the surface closure occurs, the earlier the separation of the cavitation from the tail cavity is, and the later the tail cavity contacts with the liquid surface; In the stage of surface closure, the general velocity rule of the projectile is: first increasing then decreasing, then increasing after smooth transition. When the velocity is high, the law of velocity changes to continuous decline.