Cavitation by spall fracture of solid walls in liquids

Abstract

This is the accepted version of the paper.This version of the publication may differ from the final published version. Experiments are carried out to investigate the cavitation process induced by the spill-off from material from a surface in a liquid environment. Therefore a simplified physical model was designed which allows the optical observation of the process next to a transparent glass rod submerged in a liquid where the rod is forced to fracture at a pre-defined groove. High-speed shadow-imaging and refractive index matching allow observation of the dynamics of the cavitation generation and cavitation bubble breakdown together with the flow. The results show that the initial phase of spill-off is a vertical lift-off of the rod from the surface that is normal to the direction of pendulum impact. A cavitation bubble is immediately formed during spill-off process and grows in size until lateral motion of the rod sets in. While the rod is transported away, the bubble shrinks into hyperbolic shape and finally collapses. This process is regarded as one contributing factor to the high efficiency of hydro-abrasive wear. Permanent repository link: