Investigation of oblique water entry of high-speed supercavitating projectiles using transient fluid-structure interaction simulation

This study employs a fluid-structure interaction simulation to examine the structural deformation of supercavitating projectiles during high-speed oblique water entry. A cavitation flow field simulation model is established using the VOF multiphase and cavitation models, while the structural dynamics model of the projectile is implemented using the Johnson-Cook constitutive equation. The transient fluid-structure interaction simulation is conducted through data transfer between the two models. Numerical simulations are then conducted with the assumptions of a rigid body, linear elasticity, and nonlinearity, respectively. The results indicate that the highspeed water entry induced substantial hydrodynamic force and plastic strain accumulation in the projectile, leading to considerable bending deformation. It was found that the deformation significantly influenced the hydrodynamic forces, highlighting the importance of fluid-structure interaction modeling. Moreover, the attack angle directly impacts the resulting deformation mode. Specifically, under high-speed conditions, three distinct deformation modes are observed at different attack angles: minimal deformation at low angles, an L-shaped bending at higher angles, and an S-shaped bending when the angle exceeds the threshold. This study highlights the importance of fluid-structure interaction methods in analyzing the deformation behavior of supercavitating projectiles during high-speed oblique water entry. The results show that the bidirectional dynamic interaction between fluid and structure significantly influences the structural stability of the supercavitating projectiles. The relevant conclusions can provide a reference for the optimal design of supercavitating projectiles to ensure the structural stability under high-speed conditions.