The kappa2 ovals
Relaxation of ellipses in a micro-channel
In two-phase microfluidics, droplets often undergo deformations that drive them away from their circular equilibrium shape. Herein we concentrate on the relaxation of symmetrical deformations to a circle driven by surface tension effects, which are predominant at the micrometer scales. Working in a Hele-Shaw cell, we report a generic pathway for these types of relaxations. We simulate numerically the interface shape evolution and investigate it using linear stability analysis. Finally, we characterize this universal aspect of relaxation using a purely geometrical model that is tested in experiments.
P.-T. Brun, Mathias Nagel, and François Gallaire Phys. Rev. E 88, 043009 – Published 22 October 201