Instabilitites at two-fluid interface at small Reynolds number
Goran Goranovic
Center for Fundamental Living Technology
University of Southern Denmark, Odense
Abstract:
A linear stability analysis of two shearing viscous dielectric fluids exposed to a normal electric field in plane Couette-Poiseuille flow, in the limits of small Reynolds number and negligible gravity. Two types of instability mechanisms are explored and compared: interfacial shear-stress instability due to viscosity stratification (zero and first order expansions in small Reynolds number, extending the original work by Yih [J. Fluid Mech. 27, 337 (1967)]), and interfacial electrohydrodynamic instability due to normal electric field (zero order and a special case of the first order expansion in small Reynolds number). Our results show that the electrohydrodynamic instability is zero-, whereas the shear-stress instability the first-order-Reynolds-number effect.