The effect of vapour cavitation occurrence on the hydrodynamic performance of an intercepted base-ventilated hydrofoil

Experimental results of the hydrodynamic performance of a novel high-speed hydrofoil concept are presented. The hydrofoil is symmetric, wedge shaped and makes use of a mechanism for producing a forward-facing step on either upper or lower surfaces to induce a ventilated supercavity and produce bi-directional lift. The hydrofoil remains fully-wetted at low incidence with leading edge partial vapourous cavitation and eventual suction side supercavity formation from the leading edge with incidence increase. Cavitation hysteresis as incidence is reduced back from the latter condition is significant. The corresponding detrimental effect on the resulting hydrodynamic performance is presented and shows that there is a practical upper incidence limit, analogous to stall in single phase flow, in the application of this novel hydrofoil concept.