Computational Studies of Droplet Dynamics in a Steady Electric Field

A three-dimensional spectral boundary integral algorithm has been developed to investigate the dynamics of a neutrally buoyant and initially uncharged droplet in another immiscible fluid subjected to a steady electric field. Good agreement has been found by comparing with analytical solutions and experimental results for droplets in a uniform electric field. Benefit from the fully three-dimensional algorithm that we have developed, the droplet deformation and migration induced by the nonuniform electric field created by a point charge has been investigated. We computationally predict the deformation and migration of the droplet under the influence of physical properties of the system: resistivities, permittivities and viscosities, as well as the electric capillary number. The numerical scheme developed by this study and computational results provide foundation for the computational investigation of droplet motion in digital microfluidics.