Bubble Formation from an Air Jet Injected into a Turbulent Boundary Layer

The diameter of small bubbles separated from an air jet injected into a turbulent boundary layer from a nozzle on the wall is evaluated. There exist three patterns of bubble separation that are dependent on the jet velocity, i.e., single bubble, coalesced bubbles, and a continuous air jet. The mecha...

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Bibliographic Details
Published in:Journal of fluid science and technology Vol. 5; no. 3; pp. 528 - 541
Main Authors: Kenji KATOH, Yusuke ARII, Tatsuro WAKIMOTO
Format: Journal Article
Language:English
Published: The Japan Society of Mechanical Engineers 01-11-2010
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Summary:The diameter of small bubbles separated from an air jet injected into a turbulent boundary layer from a nozzle on the wall is evaluated. There exist three patterns of bubble separation that are dependent on the jet velocity, i.e., single bubble, coalesced bubbles, and a continuous air jet. The mechanism of bubble separation from the jet is theoretically considered for the single-bubble region. First, the bubble volume is calculated when the force separating the bubbles, such as the drag or lift from the free stream, overcomes the surface tension acting on the wall. Then the total volume of the separating bubble is obtained by adding the volume supplied from the nozzle until the final separation. The diameter of a single bubble was measured for various experimental conditions. The results are well approximated by the results obtained from the theoretical considerations described in the present study.
ISSN:1880-5558
DOI:10.1299/jfst.5.528