Film flows in the presence of electric fields
Author(s)
Papageorgiou, Demetrios T
Type
Journal Article
Abstract
The presence of electric fields in immiscible multifluid flows induces Maxwell stresses at sharp interfaces that can produce electrohydrodynamic phenomena of practical importance. Electric fields can be stabilizing or destabilizing depending on their strength and orientation. In microfluidics, fields can be used to drive systems out of equilibrium to produce hierarchical patterning, mixing, and phase separation. We describe nonlinear theories of electrohydrodynamic instabilities in immiscible multilayer flows in several geometries, including flows over or inside planar or topographically structured substrates and channels and flows in cylinders and cylindrical annuli. Matched asymptotic techniques are developed for two- and three-dimensional flows, and reduced-dimension nonlinear models are derived and studied. When all regions are slender, electrostatic extensions to lubrication or shallow-wave theories are derived. In the presence of nonslender layers, nonlocal terms emerge naturally to modify the evolution equations. Analysis and computations provide a plethora of dynamics, including nonlinear traveling waves, spatiotemporal chaos, and singularity formation. Direct numerical simulations are used to evaluate the models and go beyond their range of validity to quantify phenomena such as electric field–induced directed patterning, suppression of Rayleigh–Taylor instabilities, and electrostatically induced pumping in microchannels. Comparisons of theory and simulations with available experiments are included throughout.
Date Issued
2019-01-05
Date Acceptance
2018-09-01
Citation
Annual Review of Fluid Mechanics, 2019, 51 (1), pp.155-187
ISSN
0066-4189
Publisher
Annual Reviews
Start Page
155
End Page
187
Journal / Book Title
Annual Review of Fluid Mechanics
Volume
51
Issue
1
Copyright Statement
© 2019 by Annual Reviews.
All rights reserved
All rights reserved
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Engineering & Physical Science Research Council (EPSRC)
Identifier
https://www.annualreviews.org/doi/10.1146/annurev-fluid-122316-044531
Grant Number
EP/K041134/1
EP/L020564/1
Subjects
02 Physical Sciences
04 Earth Sciences
09 Engineering
Fluids & Plasmas
Publication Status
Published
Date Publish Online
2018-09-06