Evolution of supercavitation–jet coupling on underwater vehicles

Supercavitation–jet coupling is critical for underwater high-speed vehicles, yet its dynamic mechanisms remain unclear. This study investigates the coupling characteristics via experiments in a cavitation water tunnel, combining proper orthogonal decomposition and entropy analysis. Three typical coupling states [integrated cavity (IC), partially broken cavity (PBC), and pulsating foam cavity (PFC)] are identified, evolving with jet velocity and ventilation coefficient. IC suppresses pulsations via cavity wrapping. PBC achieves optimal noise reduction (11.7 dB) through spindle-shaped cavity reconstruction. PFC exhibits high disorder but retains partial near-nozzle stabilization. Entropy jumps characterize transient state transitions, with shear effects and vortex interactions governing flow field evolution. The findings clarify coupling evolution laws and instability mechanisms, providing theoretical guidance for vehicle stability control and structural protection.