Ultrasonic Cavitation Thresholds in Water

The temperature dependence of the minimum sound pressure needed to produce cavitation in gassy water has been measured over a range of 0 to 30°C. Both plane progressive and focused waves of frequency one megacycle per second were used. The cavitation pressure threshold Pc is not a linear function of temperature, and increases by a factor of 2.5 between 30 and 0°C. About 50 percent higher sound-pressure amplitude is needed to initiate cavitation than to maintain it. The relation of Pc to the reciprocal temperature, to viscosity, and to the degree of undersaturation is discussed.