(209c) Nonlinear Particle Dynamics In a Uniform Electric Field

How do droplets respond to electric fields? A classic result due to G.I.Taylor is that a charge–free drop placed in a uniform electric field adopts a stationary prolate or oblate spheroidal shape. We report experimental observation of droplet tumbling, oscillations and chaotic dynamics occurring in uniform DC electric fields under creeping flow conditions. We develop analytical models, based on the small-deformation equations for drop dynamics, to highlight the  mechanisms by which interface deformation and charging give rise to nonlinear droplet electrohydrodynamics and rheology of emulsions.  In a complementary study, we isolate the effect of shape anisotropy by considering non-spherical particles.