Influences of fluid viscosity on the occurrences of cavitation due to sub-surface vortex

Ezure, Toshiki ; Kimura, Nobuyuki; Tobita, Akira; Kamide, Hideki 

A fundamental water experiment was performed in a cylindrical tank geometry to investigate the influences of fluid viscosity on the cavitation due to sub-surface vortex (vortex cavitation). In order to clarify the influence of fluid viscosity, the fluid temperature was varied from 10 C to 80 C to change the kinetic viscosity () of fluid from 1.310 to 3.710m/s. The occurrences of vortex cavitation were detected by image analysis on digital images of vortex cavitation captured by a digital CMOS camera. Then, the occurrences of vortex cavitation were evaluated from the relation between the yield fraction curves of vortex cavitation and the cavitation factor under several different conditions. The experimental results showed that the influence of was obvious under the large conditions. However, the influence became smaller according to the decrease of .