Session MB - Drops I. Emulsions & Drops.
MIXED session, Tuesday afternoon, November 23
Grand II, Westin Seattle
Emulsification studies show that droplets immersed in an external straining flow are easily pulled apart. In situations of comparable viscosity of the inner and outer liquid, the only stable steady-state shapes are slightly deformed drops with rounded ends, with no particular small-scale structure to them. Cohen et al., on the other hand, found in their selective withdrawal experiments that the interface between two horizontal immiscible fluid layers can evolve into a steady-state structure with an extremely sharp, cusp-like tip when a convergent flow is imposed by withdrawing the upper fluid. Although viscous stresses balance against surface tension effects in both situations, the interfaces show qualitatively different behaviors. In order to understand the reasons for this difference, we study a model in which a pendant drop at the end of an infinite nozzle is deformed by an external straining flow. the interface deformation, and its dependence on nozzle boundary conditions, are calculated via a boundary intergral simulation.