Numerical Simulation on Vertical Water Entry Impact of Axisymmetric Body at Supersonic Speed

Water entry impact is one of the hot topics in the modern underwater weapons research. With the volume of fluid (VOF) model and dynamic mesh in commercial CFD software, the water entry processes of an axisymmetric body with flat top are simulated at subsonic, transonic and supersonic speeds, respectively. The drag coefficient, head diame-ter, water compressibility and the effect of air shock wave on the water entry processes of the simulated model are ac-quired at three different speeds. Simulation results show that: 1) with the increase of speed, the peak value of drag coef-ficient first decreases then remains stable in the end, and the width of peak value decreases gradually; 2) the peak value and its width of drag coefficient increases with the increase in head diameter; 3) the water compressibility delays the appearance of the peak value of drag coefficient and reduces the peak value; and 4) air shock wave reduces the value of drag coefficient at water surface.