Flow of concentrated and highly polydisperse emulsions*

We study experiments and simulations of highly polydisperse emulsions under shear flow. By highly polydisperse, we mean with the largest droplet diameters being as much as ten times the smallest diameters. We're studying how to best define and quantify non-affine motion in these highly polydisperse samples -- motion where droplets move with displacements distinctly different from their neighbors, or from the overall imposed shear flow. The largest droplets typically move affinely, as if they are in a simple effective fluid formed by the other droplets. In contrast, the smallest droplets often move non-affinely. Additionally, we quantify how the non-affine motion diminishes as a function of droplet size. Our main conclusion is that highly polydisperse samples behave qualitatively differently than weakly polydisperse samples.