An Experimental Investigation of the Collapse of Transient Cavities in Liquids

Abstract

In the first section of this report a review of some of the attempts to measure cavity collapse pressures is presented. The second section deals with the experimental measurement of the stresses developed in a solid subjected to cavitation. Single, hemispherical cavities were created in water at the end of a pressure bar. Both the generation and collapse of such cavities gave rise to transient stress pulses which traveled along the bar and were detected by means of an X-cut quartz crystal. The charge appearing on the opposite faces of the quartz disc was allowed to develop a voltage which was subsequently amplified and :recorded photographically from an oscilloscope. The oscillograms obtained in this manner yielded information regarding both the total lifetime of the cavity and the peak amplitude of the force developed during its collapse. Concurrent with the recording of the stress pulses, high speed photographs covering the total lifetime of the cavity were taken. These photographs furnished information regarding both the maximum diameter attained by the cavity and the time history of collapse of the cavity.