Sound radiation efficiency of metals

Abstract

Measurements were made of the cavitation threshold for polypropylene glycol and for castor oil in a cylindrical resonator at approximately 16.5 kHz. The threshold for degassed castor oil was-233 dB//1/xPa peak, in agreement with the measurements of Briggs, Johnson, and Mason [J. Acoust. Soc. Am. 19, 661-664 (1947)]. Degassed polypropylene glycol exhibited wide variability in threshold, with an initial value-240 dB//1/xPa peak, dropping quickly to values-225-228 dB//1/xPa peak. Partial restoration to higher values could be attained after a five-hour rest period. [Work supported by Naval Sea Systems Command.]