Electrohydrodynamic interaction between droplet pairs in a confined shear flow

Abstract

This study deals with electrohydrodynamic interactions between two deformable droplets in a confined shear flow. We have investigated the effect of the channel confinement and the electric field strength on the droplet trajectories using numerical simulations. Two important varieties of motions are identified in the present analysis: (i) the reversing motion and (ii) the passing-over motion. This study suggests that conversion of the passing-over motion to the reversing motion or vice versa is possible by modulating the strength of the imposed electric field. Such a conversion of the pattern of droplet migration is also achieved by changing the electrical properties of the system (for instance, conductivity). Similar to the electric field strength and the electrical properties, the domain confinement is also found to play a key role in the conversion of the mode of droplet motion. Interestingly, the presence of electric field is found to prevent droplet coalescence to a certain extent depending on its strength, thus rendering the emulsion stable. Our results provide a perspective of electric field in a confined medium which can be used as a tool to modulate droplet trajectories in an emulsion.