Generation of interfacial instabilities in charged electrified viscous liquid films

Document Type

Article

Publication Date

1-1-2004

Abstract

This study is concerned with the stability of a two-dimensional incompressible conducting liquid film surrounded by a passive conducting medium, when an electric field is applied in a direction parallel to the initially flat bounding fluid interfaces. Currents generate charges at the bounding interfaces which in turn affect the stress balances there. In the absence of an electric field, the viscous liquid film is stable (instability can be induced by the inclusion of van der Waals forces for ultra thin films). A complete model is presented, at arbitrary Reynolds number, which accounts for conductivity and permittivity contrasts between the fluid and surrounding medium, as well as surface tension. The linear stability of the system is considered for arbitrary Reynolds numbers and it is shown that the stable film can become unstable if, (i) σRεp >1, or (ii) σRεp <1 and (σR −1)(1−εp)<0, where σR is the ratio of outer to inner conductivity and ϵp is the ratio of inner to outer permittivity. Instability is possible only if the electric field is non-zero and the scalings near bifurcation points that can be used to construct nonlinear theories are calculated. Several asymptotic limits are also considered including zero Reynolds numbers and short or long waves. The instability criteria given above are constructed explicitly in the case of Stokes flow.

Identifier

84874960572 (Scopus)

Publication Title

Journal of Engineering Mathematics

External Full Text Location

https://doi.org/10.1007/s10665-004-2118-1

e-ISSN

15732703

ISSN

00220833

First Page

223

Last Page

240

Issue

2-3

Volume

50

Grant

0072228

Fund Ref

National Science Foundation

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