THE INTERACTION OF A SINGLE LASER-GENERATED CAVITY IN WATER WITH A SOLID-SURFACE

This paper reexamines the collapse of a cavity in water and its role i n possible damage processes. Laser-generated cavities were formed near to a water-solid boundary and simultaneous observations made of the c ollapse processes and stresses on the solid surface. Using schlieren p hotography and a thin film transducer on the solid, the importance of fluid flow to induced material stress was determined. The stresses in the solid were also observed using dynamic photoelasticity. The cavity deformation in the collapse phase was observed with high spatial and temporal resolution. Two distinct surface stresses were observed assoc iated with bubble collapse near the boundary. The results indicate tha t one was due to a shock wave. It is postulated that the second stress was associated with fluid flow through the bubble, set up by the so-c alled ''liquid jet'' as opposed to jet impact on its own. (C) 1996 Aco ustical Society of America.