The water hammer effect formed by seawater intrusion after the navigation body is re-injected from the tube is studied. Through data analysis, the water hammer pressure phenomenon generated in the launching tube is described, and the mech- anism of water hammer pressure is analyzed. The flow field characteristics and load characteristics after seawater entering the launch tube are numerically simulated using CFD method. The water hammer pressure peak estimation model is established. The influence of the change of the speed of the vehicle out of the tube and the pressure inside the tube on the bottom pressure of the launch tube is calculated. The variation law of water hammer effect under different working conditions is obtained.
