Investigation of formation mechanism and flow pattern evolution of ventilated supercavity regulated by cavitator geometry with annular hydrofoil

Abstract

This paper experimentally and numerically investigates the transient evolution of ventilated supercavitation regulated by an annular hydrofoil, focusing on the effects of axial position, angle of attack, and diameter on cavity morphology, internal velocity, and pressure fields. The results reveal that the hydrofoil cavity consistently exhibits a dual-layer structure throughout its growth, comprising a continuous bubble-laden film at the trailing edge and an internal ventilated supercavity. When placed immediately behind the cavitator, strong stagnation and gas-entrapment effects produce a high-pressure region that elevates internal pressure. Shifting the hydrofoil downstream weakens these effects, reducing pressure and enlarging cavity diameter. Increasing the angle of attack from 0° to 10° transforms the flow from symmetric to strongly asymmetric, intensifying lower-side separation and recirculation, which shortens the cavity and disrupts the bubble-laden film. The hydrofoil diameter exhibits a threshold: only when exceeding the natural cavity diameter does it constrain the cavity, forming a bubble-laden film and expanding the high-pressure zone, thereby enhancing stability. Velocity-pressure coupling analysis demonstrates that the annular hydrofoil modulates impingement direction and flow separation, thereby controlling cavity shape and internal pressure distribution.