Jet–cavity coupling and structural response characteristics of hollow shell with truncated cone during vertical high-speed water entry

This paper adopts a coupled fluid–structure interaction method based on computational fluid dynamics and the finite element method to investigate the high-speed vertical water entry of hollow truncated cone shells and systematically reveal the regulatory mechanism of the sidewall inclination angle on their hydrodynamic and structural response characteristics. The results show that hollow truncated cone shells exhibit a unique jet–cavity coupling effect, characterized by an upward jet penetrating the shell from the bottom and an axisymmetric cavity. Shells with an acute sidewall inclination angle have the lowest velocity and displacement, which further decrease as the inclination angle decreases, while the jet height and cavity diameter increase. In contrast, shells with an obtuse sidewall inclination angle show the highest velocity and displacement, but their velocity attenuation accelerates and the jet height decreases significantly with an increasing inclination angle. In addition, the fluid force and stress of hollow truncated cone shells follow a distribution pattern of high at the bottom and low at the top, and both the peak fluid force and peak stress exhibit a monotonically decreasing trend with increasing sidewall inclination angle.