Experimental observations of inception cavitation vortices around a hydrofoils

The inception cavitation around a 2D-hydrofoil in the boundary layer of a non-separated turbulent flow was studiedexperimentally. The cavitation inceptions were observed by ahigh speed video camera, and the velocities around the hydrofoil weremeasured by a 2D-LDV. It is shown that the inception cavitation bubbles aregenerated along with a hairpin-shaped vortex coherent structure in theboundary layer of the non-separated turbulent flow. The developingprocess of an inception cavitation bubble vortice comprises generation,expanding, collapse, rebound and re-collapse. It is concluded that theinception cavitation has dual characteristics of both bubbles and coherentstructures.