Numerical Study on Air-involved Cavity during Water Exit of Underwater Vehicle

In the underwater vehicle launching process, some air in the launch tube will be involved in the low-pressure cavity formed at the shoulder part of the vehicle. This cavity mixed with air will collapse during water exit, causing dramatic change of flow field, which has a certain impact on the load environment. Based on homogeneous multiphase flow model, numerical simulation of the collapse of the cavity filled with vapor and involved air has been conducted. The results show that the nose shape with stronger cavitation ability is much easier to make the air in the launching tube involved in the low-pressure cavity. When air is mixed with vapor in the cavity, the rebound phenomenon will occur in the cavity collapse process. And there will also be multiple peaks of surface pressure.