Numerical Simulation On The Tube-Exit Load Characteristics Of Submarine-Launched Vehicle

During the vertical launching process of submarine-launched vehicle, the air in the launch tube will spread into the water and cavity will occur at the shoulder of the highly sailing vehicle, thus the vehicle is sailing in the multiphase flow of water air and cavitations. Complex fluid loads will affect on the vehicle in a very short period of time. And the loads will be quite different when the height changes. Unsteady simulations of the flow, performed with FLUENT, are presented in order to simulate the fluid fields and the structure characteristic is computed by ABAQUS. The fluid-structure interaction is achieved by MPCCI(Mesh-based parallel Code Coupling Interface).In this paper, different launching height and velocity of the vehicle are presented, the results show that the structure has bigger stress during the initial launching. and the higher velocity is, the bigger the stress will be. This also shows that the vehicle has the minimum stress under the cavitations and the stress will rise suddenly in the closed point of the cavitations and keep in a steady value afterwards. Increasing the velocity will lead to the magnify of cavitations on the shoulder, and then it will affect the position of the stress mutation. Influence to the structural loads under different head types, gaps between launch tube and air pressures within the launch tube are also studied. The results show that these three factors will affect the stress level significantly at the beginning of launching. Decrease the gap between the vehicle and launch tube or increase the pressure of air will improve the stress on the vehicle. After the head runs into water, these factors only affect the cavitation characteristics on the shoulder then change the position where the stress mutates.