(93b) Droplet Dynamics in a Steady Electric Field Via 3D Spectral Boundary Elements

The development of an efficient and accurate numerical scheme for electrically actuated droplet motion is always a challenging problem. A three-dimensional spectral boundary element method has been developed to investigate the dynamics of a neutrally buoyant droplet in another immiscible fluid subjected to a steady electric field. Both the dispersed fluid and the continuous phase are assumed leaky dielectric. The droplet is not charged initially. Good agreement has been found by comparing with analytical solutions and experimental results for droplets in uniform electric fields. Benefited from the fully three-dimensional algorithm that we recently developed, the droplet deformation and migration induced by non-uniform electric fields have been investigated. We computationally predict the droplet behavior under the influence of physical properties of the system: resistivities, permitivities and viscosities, as well as the electric capillary number. The numerical scheme developed by this study and computational results will provide foundation for the computational investigation of dielectrophoresis in digital microfluidics in which an electric field is applied to actively manipulate droplet motion.