Influence of impact velocity on the semi-sealed cylindrical shell during water entry

To study the motion characteristics and cavity evolution of the cylindrical shell with different initial velocity, the numerical simulation based on the Star-CCM+ and ABAQUS collaborative simulation method is carried out in this paper. The results show that when the shell penetrates into the water at a lower speed, only a small amount of external fluid can enter into the shell, and the internal fluid shows a reciprocating motion trend. Moreover, the speed of the shell and the force at the bottom wall show a fluctuating trend. As the speed increases, the volume of fluid entering into the interior of the shell gradually increases. After the speed reaches 30 m/s, the fluid can impact the upper wall of the shell, which also causes sudden changes in velocity and displacement. When the initial velocity of the shell reaches 80 m/s, significant deformation occurs at the upper wall of the shell, and the deformation is not fully restored after the fluid leaves the upper wall. As the speed increases, the degree of deformation gradually increases, and the volume of the cavity gradually increases.