Transition mechanism of stable motion modes for a supercavitating vehicle: Role of the cavitator cone angle

This article presents a novel discovery: the motion mechanism of supercavitating vehicles is constrained by the cone angle of the cavitator. To elucidate the influence of the cavitator cone angle on the stable motion modes and generation mechanisms of supercavitating vehicles, we adopted a combined research approach that integrates numerical simulation with theoretical analysis. This high-precision, unsteady, three-dimensional numerical simulation has been rigorously validated against experimental data. Numerical simulations were conducted to investigate the free motion of supercavitating vehicles by varying the cone angle of the cavitator. The results show that two stable motion modes are identified: single-plane tail-slapping and spatial “conic-like” oscillation. The final stable motion mode of the supercavitating vehicle is determined by the critical cavitator cone angle. When the cone angle is smaller than this critical value, the stable motion mode is tail-slapping; otherwise, it transitions to spatial conic-like oscillation. An intriguing phenomenon is observed: the supercavitating vehicle initially undergoes a tail-slapping motion before stabilizing into the spatial oscillation mode. A comparative analysis is performed on the development process, cavity–body coupling characteristics, and motion features of the two free-motion modes. Finally, the paper proposes a theoretical model to elucidate the formation mechanism of supercavitating vehicle motion modes and to determine their occurrence conditions.