Two-dimensional pulse dynamics and the formation of bound states on electrified falling films
File(s)resubmitted.pdf (2.56 MB)
Accepted version
Author(s)
Blyth, MG
Tseluiko, D
Lin, T-S
Kalliadasis, S
Type
Journal Article
Abstract
The flow of an electrified liquid film down an inclined plane wall is investigated with the focus on coherent structures in the form of travelling waves on the film surface, in particular, single-hump solitary pulses and their interactions. The flow structures are analysed first using a long-wave model, which is valid in the presence of weak inertia, and second using the Stokes equations. For obtuse angles, gravity is destabilising and solitary pulses exist even in the absence of an electric field. For acute angles, spatially non-uniform solutions exist only beyond a critical value of the electric field strength; moreover, solitary-pulse solutions are present only at sufficiently high supercritical electric-field strengths. The electric field increases the amplitude of the pulses, can generate recirculation zones in the humps and alters the far-field decay of the pulse tails from exponential to algebraic with a significant impact on pulse interactions. A weak-interaction theory predicts an infinite sequence of bound-state solutions for non-electrified flow, and a finite set for electrified flow. The existence of single-hump pulse solutions and two-pulse bound states is confirmed for the Stokes equations via boundary-element computations. In addition, the electric field is shown to trigger a switch from absolute to convective instability, thereby regularising the dynamics, and this is confirmed by time-dependent simulations of the long-wave model.
Date Issued
2018-11-25
Date Acceptance
2018-07-24
Citation
Journal of Fluid Mechanics, 2018, 855, pp.210-235
ISSN
0022-1120
Publisher
Cambridge University Press (CUP)
Start Page
210
End Page
235
Journal / Book Title
Journal of Fluid Mechanics
Volume
855
Copyright Statement
© 2018 Cambridge University Press. This paper has been accepted for publication and will appear in a revised form, subsequent to peer-review and/or editorial input by Cambridge University Press.
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000444548700005&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Technology
Physical Sciences
Mechanics
Physics, Fluids & Plasmas
Physics
low-Reynolds-number flows
MHD and electrohydrodynamics
thin films
SOLITARY WAVE DYNAMICS
INCLINED PLANE
LIQUID-FILM
HOMOCLINIC ORBITS
ACTIVE MEDIUM
STABILITY
EVOLUTION
FLOWS
INSTABILITIES
Publication Status
Published
Date Publish Online
2018-09-14