Effects of fluid viscosity on occurrence behavior of vortex cavitation; Vortex structures and occurrence condition

Ezure, Toshiki ; Ito, Kei; Kimura, Nobuyuki; Onojima, Takamitsu; Kamide, Hideki ; Kameyama, Yuri*

An experimental study on vortex cavitation was carried out in a cylindrical water tank to clarify how the viscosity of fluid influences on vortex cavitation occurrences. Vertical and horizontal velocity distributions were obtained under several experimental conditions, where the kinematic viscosity of water and the velocity of suction flow were varied as parameters. As the results, the flow patterns and the vortex structures, such as the circulation around the vortex, were grasped. And also, the acceleration behavior of vortex from the bottom of tank towards the intake of suction nozzle was clarified. Then, the occurrence map of vortex cavitation was also improved by using the present experimental data.