Water-entry and leveling trajectories of a ventilated supercavitating vehicle at different preset rudder angles

The adoption of preset rudder angles serves as an effective method for achieving trajectory flattening in supercavitating vehicles (SVs). This study investigates the stabilization mechanisms and response characteristics of the water-entry and leveling trajectories of ventilated SVs concerning the cavitator rudder angle. Numerical and experimental studies were conducted to analyze the water-entry and leveling trajectories at varying rudder angles. This research focuses on the stabilization modes and motion characteristics during the trajectory flattening process of SVs, identifying three distinct motion modes: “bilateral tail-slapping,” “unilateral tail-slapping,” and “tail-planing.” The stable motion mode depends on the preset rudder angle. When the rudder angle is minimal, the vehicle exhibits “bilateral tail-flapping” motion. An increase in the preset rudder angle restricts the upward deflection of the cylindrical section. Consequently, when the preset rudder angle increases to 6°, the motion mode transitions to tail-planing. Through comparative analysis of experimental and numerical results, this study elucidates the mechanisms underlying different stabilization motion processes.