äber Schwingungskavitation bei kurzen Schallimpulsen

The cavitation process from the growth of the nuclei to the proper cavitation oscillation may be analysed on a time base by utilizing sound pulses (20 to 5000 us). The compression waves originating from the oscillating cavities during a pulse are recorded electrically and used as a statistical measure for the cavitation. Dark field observation together with photographic recording completes the investigation.

Cavitation is examined as a function of a) pulse length and intensity of sound, b) pulse interval, and c) gas content of the fluid (water). During the growth of the nuclei the cavitation effect increases proportionally to pulse length and intensity. The characteristic of this effect becomes steeper at the beginning of the cavitation oscillations. As a result of the radiation pressure, shorter pulse intervals cause a lower density of nuclei in the sound field, and therefore cavitation becomes weaker. If the water contains gas and the pulse intervals are short enough, cavitation will recommence (secondary cavitation) depending on the relative gas content of the fluid.