Study on Water Entry Process of Vehicle Under Restriction of Underwater Ice Hole

The water entry process of a vehicle passing through an underwater ice hole is of great engineering significance in the launching operation of polar ocean detectors and the deployment strategy of related equipment in polar regions. However, the research on the water entry behavior of the vehicle under the ice hole structure is still limited, especially the lack of a systematic understanding of the coupling relationship between the cavity evolution mechanism and the dynamic response of the vehicle under the ice hole constraint. Therefore, the numerical simulation method based on computational fluid dynamics(CFD) was adopted in this paper, and the water entry process of the vehicle passing through the underwater ice hole was studied, revealing the coupling characteristics between the flow field structure, cavity evolution, and the motion state of the vehicle under the constraint of the ice hole. The results show that when the vehicle passes through the underwater ice hole, the cavity undergoes the evolution process of contraction first and then expansion, and the fluid resistance increases first and then decreases. As the vehicle gradually passes through the hole, the velocity around the wall increases significantly, and the asymmetry of the tail flow field intensifies. In addition, the velocity of the vehicle decreases when it passes through the hole, and its turning point is basically consistent with the time of cavity collapse.