The particle dynamics and shear forces of granular matter in a Couette geometry are determined experimentally. We are currently studying the response of an air-fluidized granular layer to shear. The experiment is carried out in cylindrical geometry, with a fixed outer glass cylinder and a rotating inner cylinder.
Granular material is filled into the space between cyinders and air-fluidized from below.
We use sensitive force measurements for the frictional force of the rotating inner cylinder and high speed imaging of particle positions in the thin granular layer between the outer and inner cylinder.