Convection phenomena in vibrated granular systems

This thesis investigates convection phenomena in vibrated granular systems through Discrete Element Method (DEM) simulations, recreating well-known experiments using boxes and funnels filled with granular material subjected to vertical vibration. Using these experiments, we identified an extension to the existing explanation of convection reversal. Furthermore, the flow rate decrease in a vertically vibrated hourglass, as reported by Evesque et al. [1], was successfully reproduced via DEM simulation and a physical explanation is proposed. We found the main reason for the decrease to be fluidization of the granular material high up in the hourglass. Additionally, convection rolls occupy part of the outflow cross-section, further reducing the discharge rate. In addition, simulations of vibrated pipes and boxes were performed, and the results are presented.