ACOUSTICAL AND OPTICAL TRACKING OF THE COLLAPSE OF A LASER-GENERATED CAVITATION BUBBLE NEAR A SOLID BOUNDARY

A pulse from a Nd:YAG laser is used to generate a cavitation bubble ne ar a plane solid boundary in deionised water. The different stages in the collapse of the bubble are followed using a high speed photographi c technique involving sensitive Schlieren imaging and an ultra short p ulse from a nitrogen laser pumped dye laser. The first collapse phase of the cavitation bubble is recorded with high spatial and temporal re solution. A thin film PVDF pressure transducer attached to the surface of the solid was used to study the development, of the pressure on th e surface during the bubble collapse and fluid flow was also directly observed. Both the optical and acoustical analysis techniques confirm the formation of a liquid jet and a shock wave which we believe are re sponsible for damage and erosion associated with cavitation near solid surfaces. (C) 1998 Elsevier Science B.V.