Analysis of Motion Characteristics of a Controllable Ventilated Supercavitating Vehicle Under Accelerations

The development of a maneuverable underwater high-speed vehicle is worthy of attention and study using supercavitation drag reduction theory and technology. The supercavity shape determines the hydrodynamics of the vehicle, and especially during a maneuver, its unsteady characteristics have a significant impact on the motion stability of the vehicle. The three-dimensional dynamic model of a ventilated supercavitating vehicle is established using the unsteady supercavity dynamic model based on the rigid body dynamics theory as an extension of the vehicle's longitudinal dynamic model in our recent work. The vehicle's accelerating and decelerating motions are simulated in the straight flight state using a self-developed numerical method based on the vehicle's dynamic model with the designed control law. Motion characteristics are analyzed on the evolution laws of the vehicle's motion state variables and control variables and the supercavity's characteristic parameters (i.e., ventilation cavitation number, supercavity maximum diameter and supercavity length) in the acceleration motions. The evolution laws in the accelerating and decelerating motions are compared, and the effects of the acceleration on the laws are further analyzed. This study lays the foundation for the in-depth study of the hydrodynamic characteristics and motion stability of ventilated supercavitating vehicles in maneuvering states.