Experimental Study of Low Speed Vertical Water Entry of Projectiles

Abstract

Experimental studies of the vertical water entry with different head shapes of projectiles were conducted with high-speed camera to capture the cavityrunning phase. To focus on the formation, development and closure of cavity, the projectiles of 90° cone-shaped head, elliptical head and cut-cone head to entry water at a speed of 2.8m/s were used. And the experiments of different speed vertical water entry with 90° cone-shaped head projectile were also conducted. Experimental results showed that there were four types of cavity pinch-off after projectile entered the water: quasi-static seal, shallow seal, deep seal and surface seal. There were two water jets after the closure of splash water curtain; one was upward, the other was downward. The critical water entry speed to occur cavity on the warhead of projectile was 0.64m/s.