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A Numerical Investigation of Unsteady Bubbly Cavitating Nozzle Flows

Preston, A. T. and Colonius, T. and Brennen, C. E. (2002) A Numerical Investigation of Unsteady Bubbly Cavitating Nozzle Flows. Physics of Fluids, 14 (1). pp. 300-311. ISSN 1070-6631. http://resolver.caltech.edu/CaltechAUTHORS:PREpf02

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Abstract

The effects of unsteady bubbly dynamics on cavitating flow through a converging-diverging nozzle are investigated numerically. A continuum model that couples the Rayleigh-Plesset equation with the continuity and momentum equations is used to formulate unsteady, quasi-one-dimensional partial differential equations. Flow regimes studied include those where steady-state solutions exist, and those where steady-state solutions diverge at the so-called flashing instability. these latter flows consist of unsteady bubbly shock waves traveling downstream in the diverging section of the nozzle. An approximate analytical expression is developed to predict the critical backpressure for choked flow. The results agree with previous barotropic models for those flows where bubbly dynamics are not important, but show that in many instances the neglect of bubbly dynamics cannot be justified. Finally the computations show reasonable agreement with an experiment that measures the spatial variation of pressure, velocity and void fraction for steady shockfree flows, and good agreement with an experiment that measures the throat pressure and shock position for flows with bubbly shocks. In the model, damping of the bubbly raidal motion is restricted to a simple "effective" viscosity, but many features of the flow are shown to be independent of the specific damping mechanism.


Item Type:Article
Additional Information:(Received 27 June 2000; accepted 28 August 2001) Copyright 2002 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
Record Number:CaltechAUTHORS:PREpf02
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:PREpf02
Alternative URL:http://dx.doi.org/10.1063/1.1416497
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:138
Collection:CaltechAUTHORS
Deposited By: Christopher Brennen
Deposited On:19 Oct 2004
Last Modified:26 Dec 2012 08:39

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