1. Using emulsions to study the physics of
two-dimensional frictionless granular materials
Eric R. Weeks, Physics Dept., Emory University
We use emulsion droplets confined between two parallel glass plates, so that the droplets are deformed into round quasi-two-dimensional disks. These droplet disks interact with each other like soft granular particles, but without static friction.
We pump these through a constricting channel to see how the droplets flow and rearrange. We use a microscope to image the droplets’ sizes and shapes. The forces acting on each droplet are inferred from their deformations. The left picture shows an image with lines superimposed indicating the forces. The red lines show the largest forces felt between droplets, and are most prominent near the narrow end. The right pictures show a rearrangement event, which relaxes the large forces nearby.
Side View:
~ 100 m
Top View:
Rearrangement event:
flow
1 mm