Dispersive flow of disks through atwo-dimensional Galton board

We report here an experimental and numerical study of theflow properties of disks driven by gravity through a hexagonallattice of obstacles, i.e. aGalton board. During the fall, particles experience dissipativecollisions that scatter them in random directions. Adriven-diffusion regime can be achieved under certainconditions. A characteristic length of the motion and itsdependence on geometrical parameters of the system is analyzedin the steady regime. The influence of collective effects on thedispersion process is investigated by comparison between single-and many-particle flows. The characterization of the dynamicsand the diffusive properties of the flow in a system like aGalton board can be expanded to other granular systems,particularly static solid particle mixers and will give someinsight in understanding granular mixing.