Simulation on Impact Load and Cavity Shape in High Speed Vertical Water Entry for an Axisymmetric Body

The problem of high-speed water entry of an axisymmetric body greatly influences the design of shape and trajectory for a torpedo or a missile. This paper simulates the impact and cavity shape in water entry of different head shapes, such as flat head, cone head, and round head, at the velocity between 50 ~150 m/s with the commercial software FLUENT6.3 combining with the dynamic mesh, user-define function(UDF) and MIXTURE model. Conclusions are drawn that the peak of impact load appears in the primary period of the water entry; the impact load and the cavity′s length and diameter increase with the increasing velocity; while the impact load and the cavity′s length and diameter decrease in the order of flat head, cone head, and round head when the bodies have same velocity.