Key points are not available for this paper at this time.
The dynamics of a single droplet dispersed in a continuous medium that is subjected to a superposed electric field, which consists of an alternating and a constant electric field, is studied analytically. The closed analytical expression for the deformation of the droplet due to the superposed electric field is formulated at periodic steady state by considering small deviation from the equilibrium spherical shape of the droplet. The present study reveals that the mean deformation follows the same trend as the root mean square value of the applied electric field and the mean normal electric stress across varying mixing ratios of the superposed electric field. The deformation is frequency dependent, wherein mean deformation decreases with increasing frequency and attains a constant value at higher frequencies. This phenomenon correlates with changes in surface charge density and droplet–medium interface velocity. Furthermore, the influence of medium viscosity on deformation dynamics is elucidated, showing nominal effects on mean deformation but significant impacts on deformation amplitude. In highly viscous mediums, the electro-viscous stress is countered by viscosity of the medium thereby dampening oscillation amplitudes. The study confirms that the mean deformation is a weak function of the viscosity ratio of the droplet and the medium.
Mohanty et al. (Fri,) studied this question.