Visualization and Pattern Identification of the Cavitation-Bursting Phenomenon in Propeller Tip Vortices

Marine propeller tip vortices are usually strong enough to induce cavitation in the vortex cores. Tube-shaped vapor cavity extending along the vortex trajectory becomes a way of visualizing the host tip vortex. Our preliminary observations show that, at certain flow conditions, the tip vortex cavity is going to burst into a fog-like micro-bubble cluster, along with a broad-band noise generation. This striking phenomenon and its application motivate us to study its origin and the associated multi-phase flow interactions. We plan to start by performing detailed visualization of the bursting cavitation and using the images obtained to identify the pattern of this cavity break-up process. The results are expected to elucidate the mechanisms involved, and to especially clarify the role of the non-cavitating vortex breakdown (bursting) scenario in forming such a cavitation-bursting phenomenon.