TY - JOUR
A1 - Ganchenko, Georgy S.
A1 - Mayur, Manik
A1 - Demekhin, Evgeny A.
A1 - Amiroudine, Sakir
T1 - Electrokinetic instability of liquid micro- and nanofilms with a mobile charge
T2 - Physics of Fluids
N2 - The instability of ultra-thin films of an electrolyte bordering a dielectric gas in an external tangential electric field is scrutinized. The solid wall is assumed to be either a conducting or charged dielectric surface. The problem has a steady one-dimensional solution. The theoretical results for a plug-like velocity profile are successfully compared with available experimental data. The linear stability of the steady-state flow is investigated analytically and numerically. Asymptotic long-wave expansion has a triple-zero singularity for a dielectric wall and a quadruple-zero singularity for a conducting wall, and four (for a conducting wall) or three (for a charged dielectric wall) different eigenfunctions. For infinitely small wave numbers, these eigenfunctions have a clear physical meaning: perturbations of the film thickness, of the surface charge, of the bulk conductivity, and of the bulk charge. The numerical analysis provides an important result: the appearance of a strong short-wave instability. At increasing Debye numbers, the short-wave instability region becomes isolated and eventually disappears. For infinitely large Weber numbers, the long-wave instability disappears, while the short-wave instability persists. The linear stability analysis is complemented by a nonlinear direct numerical simulation. The perturbations evolve into coherent structures; for a relatively small external electric field, these are large-amplitude surface solitary pulses, while for a sufficiently strong electric field, these are short-wave inner coherent structures, which do not disturb the surface.
KW - Mikrofilm
KW - Elektrokinetische Erscheinung
KW - Instabilität
KW - Mobilität
Y1 - 2015
UR - https://opus.hs-offenburg.de/frontdoor/index/index/docId/3597
UR - https://www.researchgate.net/publication/279155215_Electrokinetic_instability_of_liquid_micro-_and_nanofilms_with_a_mobile_charge
SN - 0899-8213
VL - 27
IS - 6
SP - 062002
ER -