Generation of interfacial instabilities in charged electrified viscous liquid films

D. T. Papageorgiou, P. G. Petropoulos

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

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.

Original languageEnglish (US)
Article number3
Pages (from-to)223-240
Number of pages18
JournalJournal of Engineering Mathematics
Volume50
Issue number2-3
DOIs
StatePublished - 2004

All Science Journal Classification (ASJC) codes

  • Mathematics(all)
  • Engineering(all)

Keywords

  • Conducting liquid film
  • Electrohydrodynamic instability
  • Leaky dielectric model
  • Linear stability

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