Numerical investigation of water-entry of a hemisphere cylinder used for micro-communication sonobuoy casing

The purpose of this paper is to present the investigation of impact pressure acting on the hemisphere cylinder when it hits the water. In this paper, a two-dimensional hemisphere cylinder is built to simulate the water-entry problem. The model enters into the calm water verticals with initial velocity in y-direction at 10m/s. The transient flow simulation is carried out using Fluent k-£ turbulent model, dynamic mesh method and 6DOF solver. The volume of fluid (VOF) and user defined function are utilized to track the free-surface and the trajectory of the impacting hemisphere cylinder. The pressure and velocity distribution is investigated. The results show the Fluent k-£ turbulent model can predict the pressure distribution on the hemisphere cylinder accurately.