Abstract:
There is great interest in the oscillation of a single cavitation bubble in a sound field. The dynamic bubble behavior is investigated by means of the acoustic backscattering of a high-frequency ultrasonic field. An experimental setup for generating single bubble cavitation is used. In addition to the driving sound field of low frequency (25 kHz) for generating the single cavitation bubble in a piezoelectric tube, a second high-frequency image sound field is radiated into the cavitation cell by a focusing PVDF transducer. The high-frequency components are scattered by the bubble and can be received by the same PVDF transducer, assuming that the bubble is placed in the focus of the transducer. For the image excitation, bursts have been used with a frequency of 30 MHz and a burst length of 20 (mu)s. The amplitude of the scattered sound depends on the temporary bubble radius. In the backscattered signal, a slight shift appears in the frequency due to the fast motion of the bubble wall. After considering the scattering behavior of a bubble theoretically, the setup for the experimental investigations and some results are presented.