  We numerically study the dynamics of a polydisperse double emulsion under a
symmetric shear flow. We show that both dispersity and shear rate crucially
affect the behavior of the innermost drops and of the surrounding shell. While
at low/moderate values of shear rates the inner drops rotate periodically
around a common center of mass triggered by the fluid vortex formed within the
emulsion generally regardless of their polydispersity, at higher values such
dynamics occurs only at increasing polydispersity, since monodisperse drops are
found to align along the shear flow and become approximately motionless at late
times. Our simulations also suggest that increasing polydispersity favours
close-range contacts among cores and persistent collisions, while hindering
shape deformations of the external droplet. A quantitative evaluation of these
effects is also provided.

Soft Condensed Matter;Fluid Dynamics