Acoustical emission of jet-edge systems using a vibrating element in water

The jet-edge system using a vibrating element (liquid whistle) was investigated experimental using high-speed camera. The vibrating element vibrated periodically with a few millimeters displacement and cavitaion bubbles were observed near the tip of the vibrating element. The acoustic emission of the system was measured with hydrophones in some place. The low frequency and shock signals were observed in the pressure signal, and whistle can be heard at the same time. In frequency field, the line and broadband spectrum exist. The foundation frequency f0 of the vibrating element and harmonics compose the line spectrum. The former 10 order harmonics can be seen obviously. As the flow velocity increasing, the frequency f0 and the harmonic do not change, but the intensity of the high order harmonics and broadband spectrum become strong. Base the experimental result, we consider that the f0 is the foundation frequency of the vibrating element, and the harmonics and the continuous spectrum is the bubble cavitatio...