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Cavitation phenomena within regions of flow separation

Katz, Joseph (1984) Cavitation phenomena within regions of flow separation. Journal of Fluid Mechanics, 140 . pp. 397-436. ISSN 0022-1120. http://resolver.caltech.edu/CaltechAUTHORS:20120709-070653778

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Abstract

The phenomenon of cavitation inception was studied on four axisymmetric bodies whose boundary layers underwent a laminar separation and subsequent turbulent reattachment. The non-cavitating flow was studied by holographic and schlieren flow-visualization techniques. Surface distributions on the mean and the fluctuating pressures were also measured. The conditions for cavitation inception and desinence were determined and holograms were recorded just prior to and at the onset of cavitation. The population of microbubbles and the subsequent development of visible cavitation was determined from the reconstructed image. In every case the appearance of visible cavitation was preceded by a cluster of microscopic bubbles in a small portion of the flow field providing clear evidence that cavitation is initiated from small nuclei. The inception zone was located within the turbulent shear layer downstream of transition and upstream of the reattachment region of the bodies with large separation regions. The location and the shape of this cavitation suggested a relation to the mixing-layer eddy structure. The inception region on the body with the smallest separation zone, a hemisphere-cylinder body, was located in the reattachment region, but the cavities were still detached from the surface. Instantaneous minimum-surface-pressure measurements do not account for observed cavitation-inception indices except for the hemisphere body, where the correlation is satisfactory. The rate of cavitation events was estimated from measurements of nuclei population, and fluctuating-pressure statistics in the portion of the flow susceptable to cavitation. It was demonstrated for the hemisphere body that at least one such cavitation event could occur every second. These findings are consistent with what is observed visually at the onset of cavitation and support the location of inception determined holographically.


Item Type:Article
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http://dx.doi.org/10.1017/S0022112084000665 DOIUNSPECIFIED
http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=376968&fulltextType=RA&fileId=S0022112084000665PublisherUNSPECIFIED
Additional Information:© 1984 Cambridge University Press. Published Online April 20 2006. Received March 14 1983. Revised November 14 1983. This work was supported by the Naval Sea System Command General Hydrodynamic Research Program, administered by David W. Taylor Naval Ship Research and Development Center, under Contract N00014-80-C-0064. This support is gratefully acknowledged. The author would like to thank Dr A. J. Acosta for his advice and guidance during the course of the present work.
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Funding AgencyGrant Number
Naval Sea System Command General Hydrodynamic Research ProgramN00014-80-C-0064
Record Number:CaltechAUTHORS:20120709-070653778
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20120709-070653778
Official Citation: Joseph Katz (1984). Cavitation phenomena within regions of flow separation. Journal of Fluid Mechanics, 140 , pp 397-436 doi:10.1017/S0022112084000665
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:32290
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:09 Jul 2012 14:51
Last Modified:26 Dec 2012 15:28

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