Study of the cavitation region and the evolution of the acoustic spectrum

An experimental setup and a technique for measuring the transient period before a stationary cavitation in a liquid by the evolution of the cavitation noise spectrum are described. The time dependences of harmonic amplitudes both near the radiator and outside the cavitation region are presented. From the form of these dependences, the characteristic transient periods preceding the stage of a fully developed cavitation in water and in transformer oil are calculated. A formal scheme for describing the cavitation region is proposed.