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Linear stability of a two-fluid interface for electrohydrodynamic mixing in a channel

Published online by Cambridge University Press:  04 July 2007

F. LI
Affiliation:
Department of Mechanical Engineering, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA
O. OZEN
Affiliation:
Department of Mechanical Engineering, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA Department of Mathematical Sciences and Center for Applied Mathematics and Statistics, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA
N. AUBRY
Affiliation:
Department of Mechanical Engineering, Carnegie Mellon University, Pittsburg, PA 15213, USA
D. T. PAPAGEORGIOU
Affiliation:
Department of Mathematical Sciences and Center for Applied Mathematics and Statistics, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA
P. G. PETROPOULOS
Affiliation:
Department of Mathematical Sciences and Center for Applied Mathematics and Statistics, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA

Abstract

We study the electrohydrodynamic stability of the interface between two superposed viscous fluids in a channel subjected to a normal electric field. The two fluids can have different densities, viscosities, permittivities and conductivities. The interface allows surface charges, and there exists an electrical tangential shear stress at the interface owing to the finite conductivities of the two fluids. The long-wave linear stability analysis is performed within the generic Orr–Sommerfeld framework for both perfect and leaky dielectrics. In the framework of the long-wave linear stability analysis, the wave speed is expressed in terms of the ratio of viscosities, densities, permittivities and conductivities of the two fluids. For perfect dielectrics, the electric field always has a destabilizing effect, whereas for leaky dielectrics, the electric field can have either a destabilizing or a stabilizing effect depending on the ratios of permittivities and conductivities of the two fluids. In addition, the linear stability analysis for all wavenumbers is carried out numerically using the Chebyshev spectral method, and the various types of neutral stability curves (NSC) obtained are discussed.

Type
Papers
Copyright
Copyright © Cambridge University Press 2007

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References

REFERENCES

Abdella, K. & Rasmussen, H. 1997 Electrohydrodynamic instability of two superposed fluids in normal electric fields. J. Comput. Appl. Maths 78, 3361.CrossRefGoogle Scholar
Baygents, J. C. & Baldessari, F. 1998 Electrohydrodynamic instability in a thin fluid layer with an electrical conductivity gradient. Phys. Fluids 10 (1), 301311.Google Scholar
Chen, C. H., Lin, H., Lele, S. K. & Santiago, J. G. 2005 Convective and absolute electrokinetic instability with conductivity gradients. J. Fluid Mech. 524, 263303.CrossRefGoogle Scholar
Chen, K. P. 1995 Interfacial instabilities in stratified shear flows of viscous and viscoelastic fluids. Appl. Mech. Rev. 48, 763776.Google Scholar
Dongarra, J. J., Straughan, B. & Walker, D. W. 1996 Chebyshev tau-QZ algorithm methods for calculating spectra of hydrodynamic stability problems. Appl. Numer. Maths 22, 399434.Google Scholar
Glasgow, I., Batton, J. & Aubry, N. 2004 Electroosmotic mixing in microchannels. Lab Chip 4, 558562.Google Scholar
Hoburg, J. F. & Melcher, J. R. 1976 Internal electrohydrodynamic instability and mixing of fluids with orthogonal field and conductivity gradients. J. Fluid Mech. 73, 333351.CrossRefGoogle Scholar
Hooper, A. P. 1989 The stability of two superposed viscous fluids in a channel. Phys. Fluids 1 (7), 11331142.CrossRefGoogle Scholar
Hooper, A. P. & Boyd, W. G. C. 1983 Shear-flow instability at the interface between two viscous fluids. J. Fluid Mech. 128, 507528.CrossRefGoogle Scholar
Joseph, D. D. & Renardy, Y. Y. 1993 Fundamentals of Two-Fluid Dynamics, Part I: Mathematical Theory and Applications. Springer.Google Scholar
Lin, H., Storey, B. D., Oddy, M. H., Chen, C. H. & Santiago, J. G. 2004 Instability of electrokinetic microchannel flows with conductivity gradients. Phys. Fluids 16 (6), 19221935.Google Scholar
Melcher, J. R. 1963 Field Coupled Surface Waves. MIT Press.Google Scholar
Melcher, J. R. & Schwarz, W. J. 1968 Interfacial relaxation overstability in a tangential electric-field. Phys. Fluids 11 (12), 2604.Google Scholar
Melcher, J. R. & Smith, C. V. 1969 Electrohydrodynamic charge relaxation and interfacial perpendicular-field instability. Phys. Fluids 12 (4), 778.CrossRefGoogle Scholar
elMoctar, A. O. Moctar, A. O., Aubry, N. & Batton, J. 2003 Electro-hydrodynamic micro-fluidic mixer. Lab Chip 3, 273280.Google Scholar
Mohamed, A. A., Elshehawey, E. F. & ElSayed, M. F. 1995 Electrohydrodynamic stability of two superposed viscous fluids. J. Colloid Interface Sci. 169, 6578.CrossRefGoogle Scholar
Nagata, M. 1990 Three-dimensional finite-amplitude solutions in plane Couette flow: bifurcation from infinity. Appl. Mech. Rev. 217, 519527.Google Scholar
Orszag, S. A. 1971 Accurate solution of the Orr–Sommerfeld stability equation. J. Fluid Mech. 50, 689.Google Scholar
Ozen, O., Aubry, N., Papageorgiou, D. T. & Petropoulos, P. G. 2006 natexlaba Electrohydrodynamic linear stability of two immiscible fluids in channel flow. Electrochim. Acta 51, 53165323.CrossRefGoogle Scholar
Ozen, O., Aubry, N., Papageorgiou, D. T. & Petropoulos, P. G. 2006 natexlab b Monodisperse drop formation in square microchannels. Phys. Rev. Lett. 94, 144501.Google Scholar
Ozen, O., Papageorgiou, D. T. & Petropoulos, P. G. 2006 c Nonlinear stability of a charged electrified viscous liquid film under the action of a horizontal electric field. Phys. Fluids 18, 042102.CrossRefGoogle Scholar
Papageorgiou, D. T. & Petropoulos, P. G. 2004 Generation of interfacial instabilities in charged electrified viscous liquid films. J. Engng Maths. 50 (23), 223240.CrossRefGoogle Scholar
Papageorgiou, D. T. & Vanden-Broeck, J.-M. 2004 Large-amplitude capillary waves in electrified fluid sheets. J. Fluid Mech. 508, 7188.Google Scholar
Renardy, Y. 1985 Instability at the interface between two shearing fluids in a channel. Phys. Fluids 28 (12), 34413443.CrossRefGoogle Scholar
Renardy, Y. 1987 The thin-layer effect and interfacial stability in a two-layer Couette flow with similar liquids. Phys. Fluids 30 (6), 16271637.Google Scholar
Savettaseranee, K., Papageorgiou, D. T., Petropoulos, P. G. & Tilley, B. S. 2003 The effect of electric fields on the rupture of thin viscous films by van der Waals forces. Phys. Fluids 15 (3), 641652.CrossRefGoogle Scholar
Saville, D. A. 1997 Electrohydrodynamics: the Taylor–Melcher leaky dielectric model. Annu. Rev. Fluid Mech. 29, 2764.CrossRefGoogle Scholar
Storey, B. D., Tilley, B. S., Lin, H. & Santiago, J. G. 2005 Electrokinetic instabilities in thin microchannels. Phys. Fluids 17, 018103.CrossRefGoogle Scholar
Tardu, S. 2004 Interfacial electrokinetic effect on the microchannel flow linear stability. Trans. ASME I: J. Fluids Engng 126, 1013.Google Scholar
Tilley, B. S., Petropoulos, P. G. & Papageorgiou, D. T. 2001 Dynamics and rupture of planar electrified liquid sheets. Phys. Fluids 13 (12), 35473563.Google Scholar
Yiantsios, S. G. & Higgins, B. G. 1988 Linear stability of plane Poiseuille flow of two superposed superposed fluids. Phys. Fluids 31 (11), 32253238.Google Scholar
Yih, C.-S. 1967 Instability due to viscosity stratification. J. Fluid Mech. 27, 337352.Google Scholar