Numerical Study on High-Speed Water Entry of Vehicle Based on Structured Arbitrary Lagrangian-Eulerian Method

High-speed water entry of the vehicle is recognized as a typical fluid-structure interaction process. Due to the abrupt change in density of the surrounding fluid medium, the vehicle is subjected to instantaneous extreme loads, which may result in damage to its shell structure and loss of control over its trajectory. To further explore the load characteristics and structural deformation during high-speed water entry, a numerical model for the high-speed water entry is established based on the Structured Arbitrary Lagrangian-Eulerian method. Compared with experimental results, favorable predictive accuracy is demonstrated by this numerical model. Using this model, numerical simulations under different entry angles are conducted, and parameters such as acceleration, pressure, and stress during the water entry are systematically acquired. Additionally, the time-domain characteristics of these parameters are analyzed. It is shown by the results that axial loads are primarily borne by the vehicle during water entry, while the amplitude of normal loads is relatively small. When oblique water entry occurs, an asymmetric mechanical distribution is presented at the vehicle's head. Meanwhile, in the initial stage of water entry, alternating structural responses - specifically inward concave deformation and outward convex deformation - are exhibited at the vehicle's head.