Dynamic of cavitation bubble in a flowing liquid with a pressure gradient

In the present study, a high energy pulsed laser is used to generate a millimetric cavitation bubble within a water °ow over a symmetric hydrofoil. The bubble is initiated at di®erent locations in the vicinity of the hydrofoil leading edge. A high speed camera is used to observe the motion of the bubble as it travels along the hydrofoil suction side. Besides the stando® parameter, we have found that the pressure gradient plays a major role on bubble dynamic and subsequent phenomena. For a speci¯c initial location of the bubble, the micro-jet is no more directed towards the hydrofoil surface, as commonly observed in still water. In this case, we have also observed a spectacular behaviour of the cavity rebound, which migrates towards the solid surface despite of the outward direction of the micro-jet. This result di®ers from the behaviour of a bubble near a solid surface in water at rest or water °owing uniformly since the micro-jet is normally directed toward the solid. Supported by Swiss National Science Foundation (Grant No 200020-116641)