High-Speed Supercavitating Vehicles (HSSVs) are characterized by substantially reduced hydrodynamic drag from the fully wetted underwater vehicles. Drag is localized at the nose, where a cavitator generates a cavity that completely envelops the body. In this paper, a vertical plane model incorporated with time-delay effect (memory effect of cavity-vehicle interaction) is developed. Unlike previous models, the authors focus on the immersion angle between supercavity and vehicle used to determine the planing force. Stability analyses are carried out with the delay-dependent pitch-plane model. And a key problem is shown that this time-delay leads to destabilization of limit-cycle motion. A new PID control-algorithm with up-and-down rudder mode is designed, demonstrated by both numerical and experimental studies. The research may be useful for developing the trajectory control system of HSSVs.

A spatial kinetics model for supercavitating vehicles including the coupled motion of pitch, yaw, and rolling was presented. Mathematical simulations were performed to investigate dynamic performance of supercavitating vehicles. An intrinsic conic-like oscillation in the motion of supercavitating vehicles was discovered. A lakebed experiment was carried out to validate the oscillation. Good agreement is achieved between simulation and experiment in terms of the amplitude and frequency of attitude angles. The steady phase difference between the motions in different planes is also accurately captured which is about π/2. The conic-like oscillation is attributed to the occurrence of the tail-slap motion in the vertical and horizontal planes and the steady phase difference.

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