TY - JOUR
U1 - Zeitschriftenartikel, wissenschaftlich - begutachtet (reviewed)
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
JF - 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://www.researchgate.net/publication/279155215_Electrokinetic_instability_of_liquid_micro-_and_nanofilms_with_a_mobile_charge
SN - 0899-8213
DO - https://dx.doi.org/10.1063/1.4921779
VL - 27
IS - 6
SP - 062002
ER -
TY - JOUR
U1 - Zeitschriftenartikel, wissenschaftlich - begutachtet (reviewed)
A1 - Navakar, Abhishek
A1 - Amiroudine, Sakir
A1 - Mayur, Manik
A1 - Demekhin, Evgeny A.
T1 - Long-wave interface instabilities of a two-liquid DC electroosmotic system for thin films
JF - Microfluidics and Nanofluidics
N2 - Instabilities of the interface between two thin liquid films under DC electroosmotic flow are investigated using linear stability analysis followed by an asymptotic analysis in the long-wave limit. The two-liquid system is bounded by two rigid plates which act as substrates. The Boltzmann charge distribution is considered for the two electrolyte solutions and gives rise to a potential distribution in these liquids. The effect of van der Waals interactions in these thin films is incorporated in the momentum equations through the disjoining pressure. Marginal stability and growth rate curves are plotted in order to identify the thresholds for the control parameters when instabilities set in. If the upper liquid is a dielectric, the applied electric field can have stabilizing or destabilizing effects depending on the viscosity ratio due to the competition between viscous and electric forces. For viscosity ratio equal to unity, the stability of the system gets disconnected from the electric parameters like interface zeta potential and electric double-layer thickness. As expected, disjoining pressure has a destabilizing effect, and capillary forces have stabilizing effect. The overall stability trend depends on the complex contest between all the above-mentioned parameters. The present study can be used to tune these parameters according to the stability requirement.
KW - Elektroosmose
KW - Wellenleiter
KW - Schnittstelle
Y1 - 2015
SN - 1613-4982
DO - https://dx.doi.org/10.1007/s10404-015-1606-0
VL - 19
IS - 4
SP - 813
EP - 827
PB - Springer
CY - Berlin, Heidelberg
ER -