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The double layer–capillary stability of an annular electrolyte fluid surrounding a dielectric-fluid core in a tube

Published online by Cambridge University Press:  26 April 2006

E. Georgiou
Affiliation:
The Levich Institute and Department of Chemical Engineering, City College of CUNY, 140th Street at Convent Avenue, New York, NY 10031, USA
D. T. Papageorgiou
Affiliation:
The Levich Institute and Department of Chemical Engineering, City College of CUNY, 140th Street at Convent Avenue, New York, NY 10031, USA
C. Maldarelli
Affiliation:
The Levich Institute and Department of Chemical Engineering, City College of CUNY, 140th Street at Convent Avenue, New York, NY 10031, USA
D. S. Rumschitzki
Affiliation:
The Levich Institute and Department of Chemical Engineering, City College of CUNY, 140th Street at Convent Avenue, New York, NY 10031, USA

Abstract

In this paper we examine the linear stability of an annular film surrounding a dielectric-fluid core in a tube in the presence of double layers of charges at the film core and at the film–tube interfaces, when the fluid-fluid interface is of low tension. In the absence of electrostatic forces, the surface tension force arising from the circumferential curvature destabilizes, and that from the axial curvature stabilizes the system. The competition is such that waves larger than the unperturbed interface circumference are unstable and those shorter are stable. For charged layers in the film, two cases are examined: (i) double-layer repulsion where the volume charge density is everywhere of the same sign and (ii) double-layer attraction where the diffusive layers next to the film interfaces are of opposite signs. In the first case, double-layer repulsion and surface tension lowering stabilize the destabilizing action of the circumferential component of the surface tension force, and a window of stability can exist. In the case of double layers of opposite signs, double-layer attraction destabilizes the system, and growth rates larger than those caused by pure capillarity can arise. Finally, for the case of a core bounded by an infinite electrolyte, surface tension lowering stabilizes the destabilizing action of the circumferential component of the surface tension force and destabilizes the longitudinal one, although the magnitudes of these effects may differ. As a result the thread can become unstable to waves shorter than the interface circumference.

Type
Research Article
Copyright
© 1991 Cambridge University Press

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References

Abramowitz, M. & Stegun, I. A., 1972 Handbook of Mathematical Physics. Dover.
Bleys, G. & Joos, P., 1985 Adsorption kinetics of bolaform surfactants at the air/water interface. J. Phys. Chem. 89, 10271032.Google Scholar
Chandrasekhar, S.: 1953 Hydrodynamic and Hydromagnetic Stability. Oxford University Press.
Felderhof, B. U.: 1953 Dynamics of free liquid films. J. Chem. Phys. 49, 4451.Google Scholar
Frenkel, A. L., Babchin, A. J., Levich, B. G., Shlang, T. & Sivashinsky, G. I., 1987 Annular flows can keep unstable films from breakup: nonlinear saturation of capillary instability. J. Colloid Interface Sci. 115, 225233.Google Scholar
Gallez, D. & Coakly, G., 1986 Interfacial instability at cell membranes. Prog. Biophys. Molec. Biol. 48, 155199.Google Scholar
Goren, S. L.: 1962 The instability of an annular thread of fluid. J. Fluid Mech. 27, 309319.Google Scholar
Havenbergh, J. V. & Joos, P., 1983 The dynamic surface tension in a free falling film. J. Colloid Interface Sci. 95, 172181.Google Scholar
Hickox, C. E.: 1971 Instability due to viscosity and density stratification in axisymmetric pipe flow. Phys. Fluids 14, 251262.Google Scholar
Hu, H. H. & Joseph, D. D., 1989 Lubricated pipelines: stability of core-annular flow. Part 2. J. Fluid Mech. 205, 359396.Google Scholar
Jain, R. K. & Maldarelli, M., 1988 The hydrodynamic stability of thin films. In Thin Films (ed. I. B. Ivanov). Marcel Dekker.
Joskph, D. D., Renardy, Y. & Renardy, M., 1984 Instability of the flow of immiscible liquids with different viscosities in a pipe. J. Fluid Mech. 141, 309317.Google Scholar
Melcher, J. R.: 1981 Continuum Electromechanics. MIT Press.
Melcher, J. R. & Taylor, G. I., 1969 Electrohydrodynamics. Ann. Rev. Fluid Mech. 1, 111146.Google Scholar
Miller, C. A. & Scriven, L. E., 1970a Interfacial instability due to electrical forces in double layers. (I). General considerations. J. Colloid Interface Sci. 33, 360370.Google Scholar
Miller, C. A. & Scriven, L. E., 1970b Interfacial instability due to electrical forces in double layers. (II). Stability of interfaces with diffuse layers. J. Colloid Interface Sci. 33, 371383.Google Scholar
Papageorgiou, D. T., Maldarelli, C. & Rumschitzki, D. S., 1990 Nonlinear interfacial stability of core-annular film flow. Phys. Fluids A 2, 340352.Google Scholar
Preziosi, K., Chen, K. & Joseph, D. D., 1989 Lubricated pipelines: stability of core-annular flow. J. Fluid Mech. 201, 323356.Google Scholar
Rayleigh, Lord: 1879 On the capillary phenomena of jets. Appendix I. Proc. R. Soc. Lond. A 29, 71.Google Scholar
Rayleigh, Lord: 1892 On the instability of a cylinder of viscous liquid under capillary force. Phil. Mag. 34, 145.Google Scholar
Saez, A. E., Larbeniell, K. G. & Lerec, J., 1986 The hydrodynamics of trickling flow in packed beds I: Conduit models. AIChE J. 32, 353.Google Scholar
Saville, D. A.: 1970 Electrohydrodynamic stability: fluid cylinders in longitudinal electric fields. Phys. Fluids 13, 29872994.Google Scholar
Saville, D. A.: 1971 Electrohydrodynamic stability: effects of charge relaxation at the interface of a liquid jet. J. Fluid Mech. 48, 815827.Google Scholar
Tomotika, S.: 1935 On the stability of a cylindrical thread of a viscous liquid surrounded by another viscous liquid. Proc. R. Soc. Lond. A 150, 322337.Google Scholar
Yih, C. S.: 1967 Instability due to viscosity stratification., J. Fluid Mech. 27, 337352.Google Scholar