Janssen Effect in a 2D Grain Silo with Photoelastic Particles

This work examines the Janssen effect 2D silo, using photoelastic disks as the grains. As the total height of particles in a system increases, the effective mass at the bottom of the silo is less than the total mass of the particles. This is because some of the weight is supported by the walls, as frictional force chains can act to redirect the weight force to the walls. By using photoelastic particles, we can characterize the statistics of the force chain network of a packing. For repeated experiments at a particular filling height, there will be differences in the force chain structure and statistics, due to the stochastic nature of filling the system. We seek to characterize the full spectrum of the system’s microstates for a given packing height. We repeat this analysis for differing heights in the system. This work will be used as a future diagnostic as we study the flow of particles and jamming around obstacles in this silo.