Generation of Ultrasonic-Wave by a Submerged Water Jet

Abstract

Submerged water jet accompanied by ultrasonic-waves is considered to be able to warm up bones under the skin effectively and it is utilized at the rehabilitation facilities. However, there exist few reports about the submerged water jet with ultrasonic-waves. In this paper, an experimental study of ultrasonic- wave generated by a submerged water jet has been carried out using various size of the nozzle and varying jet velocity. Sound pressure level (SPL) is measured by a hydrophone in a water tank. It is found that the water jet without air mixed and that water mixed show higher SPL in the range of ultrasonic-wave than the conventional jet with air mixed, whereas SPL of the former at low frequency is decreased remarkably. Furthermore, SPL for the jet without air mixed persists to the downstream section. In the case of the jet without air mixed, a cap installed at the outlet of the nozzle is found to enhance SPL of the ultrasonic-wave, and optimum sizes of the nozzle are clarified. In addition, an increase in SPL in the range of the ultrasonic-wave is confirmed to be related to the cavitation, but the generation of ultrasonic-wave doesn't depend only on the cavitation.