The Effects of Salt Water on Bubble Cavitation

Abstract

Experiments were performed to examine differences in bubble cavitation inception, form, and acoustic emission in fresh and salt water. The tests were conducted on an axisymmetric headform known as the ITTC body, and acoustic emission, cavitation bubble size, and cavitation event rates were measured for a variety of cavitation numbers and dissolved air contents at a fixed dynamic head for both fresh and salt water. Differences were detected in the cavitation inception index, cavitation bubble size distribution, and the resulting overall acoustic emission. These differences may be attributed to variations in the freestream nuclei population, and it is hypothesized that the solution of salt reduced the number and size of freestream nuclei. Differences in the overall acoustic emission were attributed to variation in the bubble event rate and average maximum bubble size between the fresh and salt water cavitation.