Observation of inception of sheet cavitation from free nuclei

Wakana Tsuru, Takafumi Konishi, Satoshi Watanabe, Shin ichi Tsuda

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Prediction of inception of sheet cavitation on solid walls has been recognized to be very difficult, since it is significantly affected by the boundary layer flow characteristics, the population of free nuclei, the nuclei held in the wall roughness, the amount of dissolved air in liquid and so on. It has not sufficiently been made clear how the inception is affected by the conditions of water qualities and background flow characteristics. In this study, high speed observation of inception of sheet cavity from free nuclei is conducted for a two-dimensional convergent- divergent nozzle flow, where the sheet cavity forms just downstream of the nozzle throat. The effects of the amount of dissolved air and the free stream velocity on the inception process of sheet cavitation is examined. In addition, the bubble nuclei density, which is well known to be important factor for cavitation inception, is passively controlled by the filter installed in the tunnel. From the observations, it is confirmed that the nuclei number density significantly affects the formation of sheet cavity rather than the other two parameters. In conditions with large nuclei number density, the sheet cavity does not form, and bubbly cavitation appears instead. In the case with small nuclei number density, the sheet cavity forms from a single flowing nucleus and develops streamwisely and spanwisely. In the conditions with medium nuclei number density, the sheet cavity also forms but is shorter/ narrower streamwisely/spanwisely, due to interaction of other nuclei flowing near the formed sheet cavity.

Original languageEnglish
Pages (from-to)223-228
Number of pages6
JournalJournal of Thermal Science
Volume26
Issue number3
DOIs
Publication statusPublished - Jun 1 2017

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cavitation flow
nuclei
cavities
flow characteristics
convergent-divergent nozzles
nozzle flow
water quality
boundary layer flow
throats
air
free flow
nozzles
tunnels
roughness
bubbles
high speed
filters
liquids

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

Cite this

Observation of inception of sheet cavitation from free nuclei. / Tsuru, Wakana; Konishi, Takafumi; Watanabe, Satoshi; Tsuda, Shin ichi.

In: Journal of Thermal Science, Vol. 26, No. 3, 01.06.2017, p. 223-228.

Research output: Contribution to journalArticle

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