TITLE:
Periodic Behavior of Cavitation Cloud Shedding in Submerged Water Jets Issuing from a Sheathed Pipe Nozzle
AUTHORS:
Guoyi Peng, Ayaka Wakui, Yasuyuki Oguma, Seiji Shimizu, Hong Ji
KEYWORDS:
Water Jet, Cavitation, Cavitation Cloud, Visualization, Image Analysis
JOURNAL NAME:
Journal of Flow Control, Measurement & Visualization,
Vol.6 No.1,
January
3,
2018
ABSTRACT: The behavior of cavitation cloud shedding in submerged water jets issuing from a sheathed pipe nozzle is investigated experimentally by high-speed camera visualization observation. Experiments are carried out under different cavitation numbers decreased to 0.01 with increase of the injection pressure, and the frequency spectrum of cavitation cloud shedding is evaluated by statistical analysis of a sequence of high-speed camera images. Experiments demonstrate that cavitation clouds appear when the cavitation number σ decreases to the level of 0.5-0.7 and developed cavitation clouds shed downstream periodically at multiple frequencies. The low frequency components of cavitation cloud shedding is basically dependent upon the pressure pulsation of plunger pump, which is often employed in various industry application of water jets. However, the high frequency components are closely related to the shedding of vortexes and the collapsing of cavitation clouds, which are dependent on the flow structure of submerged jets and the property of cavitation clouds consisted of numerous bubbles.