EQUILIBRIUM OF VENTILATED CAVITIES IN TIP VORTICES

The behavior of air cavities formed in the tip vortex trailing from re ctangular and elliptical planform hydrofoils has been examined both th eoretically and experimentally. These cavities have some peculiarities , in particular their ability to move upstream and reach a stable posi tion near the hydrofoil. Detailed measurements of the the velocity com ponents and the cavity characteristics have been made. The results are compared with the predictions of a theoretical model based on the equ ilibrium balance of a cavity developing in a Lamb vortex.