Hostname: page-component-cd9895bd7-jn8rn Total loading time: 0 Render date: 2024-12-19T09:44:30.734Z Has data issue: false hasContentIssue false

On the buoyancy-driven motion of a drop towards a rigid surface or a deformable interface

Published online by Cambridge University Press:  26 April 2006

Stergios G. Yiantsios
Affiliation:
Department of Chemical Engineering and Center for Low Gravity Fluid Mechanics and Transport Phenomena, University of Colorado, Boulder, CO 80309-0424, USA
Robert H. Davis
Affiliation:
Department of Chemical Engineering and Center for Low Gravity Fluid Mechanics and Transport Phenomena, University of Colorado, Boulder, CO 80309-0424, USA

Abstract

The deformation of a viscous drop, driven by buoyancy towards a solid surface or a deformable interface, is analysed in the asymptotic limit of small Bond number, for which the deformation becomes important only when the drop is close to the solid surface or interface. Lubrication theory is used to describe the flow in the thin gap between the drop and the solid surface or interface, and boundary-integral theory is used in the fluid phases on either side of the gap. The evolution of the drop shape is traced from a relatively undeformed state until a dimple is formed and a long-time quasi-steady-state pattern is established. A wide range of drop to suspending phase viscosity ratios is examined. It is shown that a dimple is always formed, independently of the viscosity ratio, and that the long-time thinning rates take simple forms as inverse fractional powers of time.

Type
Research Article
Copyright
© 1990 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Ascoli, E. P. 1988 The effects of a planar wall on the low Reynolds number motion of solid particles, drops and bubbles. Ph.D thesis, Cal. Inst. Tech., Pasadena, California.
Barnocky, G. & Davis, R. H. 1989 The lubrication force between spherical drops, bubbles and rigid particles in a viscous fluid. Intl J. Multiphase Flow 15, 627638.Google Scholar
Batchelor, G. K. 1967 An Introduction to Fluid Dynamics. Cambridge University Press.
Chen, J.-D. 1984 Effects of London—van der Waals and electric double layer forces on the thinning of a dimpled film between a soap drop or bubble and a horizontal solid surface. J. Colloid. Interface Sci. 98, 329341.Google Scholar
Chi, B. K. & Leal, L. G. 1989 A theoretical study of the motion of a viscous drop towards a fluid interface at low Reynolds numbers. J. Fluid Mech. 201, 123146.Google Scholar
Davis R. H., Schonberg, J. A. & Rallison, J. M. 1989 The lubrication force between two viscous drops. Phys. Fluids A 1, 7781.Google Scholar
Davis, R. H., Serayssol, J.-M. & Hinch, E. J. 1986 The elastohydrodynamic collision of two spheres. J. Fluid Mech. 163, 479497.Google Scholar
Derjaguin, B. & Kussakov, M. 1939 Anomalous properties of thin poly-molecular films. Acta Physicochim. URSS 10, 2530.Google Scholar
Dimitrov, D. S. & Ivanof, I. B. 1978 Hydrodynamics of thin liquid films. On the rate of thinning of microscopic films with deformable interfaces. J. Colloid. Interface Sci. 64, 97106.Google Scholar
Frankel, S. P. & Mysels, K. J. 1962 On the dimpling during the approach of two interfaces. J. Phys. Chem. 66, 190191.Google Scholar
Hartland, S. 1967 The approach of a liquid drop to a flat plate. Chem. Engng Sci. 22, 16751687.Google Scholar
Hartland, S. 1969 The profile of a draining film beneath a liquid drop approaching a plane interface. Chem. Engng Prog. Symp. Ser. (91) 65, 8287.Google Scholar
Hartland, S. & Robinson, J. D. 1977 A model for an axisymmetric dimpled draining film. J. Colloid. Interface 60, 7281.Google Scholar
Jones, A. F., Wilson, S. D. R. 1978 The film drainage problem in droplet coalescence. J. Fluid Mech. 87, 263288.Google Scholar
Lamb, H. 1932 Hydrodynamics. Cambridge University Press.
Lin, C. Y. & Slattery, J. C. 1982 Thinning of a liquid film as a small drop or bubble approaches a solid plane. AIChE J. 28, 147156.Google Scholar
Pozrikidis, C. 1990 The deformation of a liquid drop moving normal to a plane wall. J. Fluid Mech. 215, 331363.Google Scholar
Wacholder, E. & Weihs, D. 1972 Slow motion of a fluid sphere in the vicinity of another sphere or a plane boundary. Chem. Engng Sci. 27, 18171828.Google Scholar