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Critical microjets in collapsing cavities

Published online by Cambridge University Press:  26 April 2006

Michael S. Longuet-Higgins
Affiliation:
Institute for Nonlinear Science, University of California, San Diego, La Jolla, California 92093-0402, USA
Hasan Oguz
Affiliation:
Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA

Abstract

Inward microjets are commonly observed in collapsing cavities, but here we show that jets with exceptionally high velocities and accelerations occur in certain critical flows dividing jet formation from bubble pinch-off. An example of the phenomenon occurs in the family of flows which evolve from a certain class of initial conditions: the initial flow field is that due to a moving point sink within the cavity.

A numerical study of the critical flow shows that in the neighbourhood of microjet formation the flow is self-similar. The local accelerations, velocities and distances scale as tβ-2, tβ-1 and tβ respectively, where β = 0.575. The velocity potential is approximately a spherical harmonic of degree ¼.

Type
Research Article
Copyright
© 1995 Cambridge University Press

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References

Blake, J. R., Tait, B. B. & Doherty, G. 1987 Transient cavities near boundaries. Part 1. Rigid boundary. J. Fluid Mech. 170, 479497.Google Scholar
Blanchard, D. C. & Woodcock, A. H. 1980 The production, concentration and vertical distribution of the sea-salt aerosol. Ann. N.Y. Acad. Sci. 338, 330347.Google Scholar
Cooker, M. J. & Peregrine, D. H. 1991 Violent motion as near-breaking waves meet a wall. In Breaking Waves, Proc. IUTAM Symp. Sydney, Australia (ed. M. L. Banner & R. H. J. Grimshaw), pp. 291297. Springer, 387 pp.
John, F. 1953 Two-dimensional potential flows with a free boundary. Commun. Pure Appl. Maths 6, 497503.Google Scholar
Kornfeld, M. & Suvorov, L. 1944 On the destructive action of cavitation. J. Appl. Phys. 15, 495506.Google Scholar
Longuet-Higgins, M. S. 1983 Bubbles, breaking waves and hyperbolic jets at a free surface. J. Fluid Mech. 127, 103121.Google Scholar
Longuet-Higgins, M. S. 1990 An analytical model of sound production by raindrops. J. Fluid Mech. 214, 395410.Google Scholar
Longuet-Higgins, M. S. 1993 Highly-accelerated, free-surface flows. J. Fluid Mech. 248, 449475.Google Scholar
Longuet-Higgins, M. S. 1994 Inertial shocks in surface waves and collapsing bubbles. Proc. IUTAM Symp. on Bubble Dynamics and Interface Phenomena, Birmingham, UK, 6-9 Sep. 1993.
Medwin, H. & Beaky, M. M. 1989 Bubble sources of the Knudsen and sea noise spectra. J. Acoust. Soc. Am. 86, 11241130.Google Scholar
Oguz, H. N. & Prosperetti, A. 1993 Dynamics of bubble growth and detachment from a needle. J. Fluid Mech. 257, 111145.Google Scholar
Prosperetti, A., Crum, L. S. & Pumphrey, H. C. 1989 The underwater noise of rain. J. Geophys. Res. 94, 32553259.Google Scholar
Pumphrey, H. C. & Crum, L. A. 1988 Acoustic emissions associated with drop impacts. In Sea Surface Sound (ed. B. R. Kerman), pp. 463483. Dordrecht: Reidel, 639 pp.