Paper Number
SC48
Session
Suspensions and Colloids
Title
Electro-hydro-dynamic interactions of leaky dielectric drops
Presentation Date and Time
October 12, 2022 (Wednesday) 3:45
Track / Room
Track 1 / Sheraton 4
Authors
- Kach, Jeremy I. (Carnegie Mellon University, Chemical Engineering)
- Walker, Lynn M. (Carnegie Mellon University, Chemical Engineering)
- Khair, Aditya (Carnegie Mellon University, Department of Chemical Engineering)
Author and Affiliation Lines
Jeremy I. Kach, Lynn M. Walker and Aditya Khair
Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213
Speaker / Presenter
Khair, Aditya
Keywords
experimental methods; theoretical methods; emulsions; suspensions
Text of Abstract
Application of an electric field across the curved interface of two fluids of low but non-zero conductivities, or ‘leaky dielectrics,’ can give rise to electric stresses that drive sustained fluid flow. In a uniform DC electric field of sufficiently weak magnitude, the electric and velocity fields around an isolated, neutrally buoyant leaky dielectric drop at zero Reynolds number are fore-aft and azimuthally symmetric about the applied field axis. Consequently, the drop remains stationary. The presence of a second drop breaks these symmetries, resulting in relative motion of the drop pair. Recently, Sorgentone et al. (JFM, 2021) derived an analytical expression for the relative velocity of a pair of widely separated drops of identical constitution, asymptotic in the inverse separation distance between the drop centroids. In the present work, we generalize the theory of Sorgentone et al. to interactions of dissimilar drops (of different size or constitution), and the pairwise additive interactions of three or more drops. We perform experiments on silicone oil drops suspended in castor oil and compare to asymptotic predictions of the drop pair trajectories. Experimental trajectories of two, three, and four arbitrarily placed drops are shown to be qualitatively predicted by our theory. The interactions of multiple, dissimilar drops are also described.