Three-dimensional discrete element models for the granular statics and dynamics of powders

A novel coarse graining scheme for the discrete element method (DEM) was developed which allows for the representation of a given granular system using artificially enlarged grains. Based on the conservation of the local energy density, a dimensional analysis yielded scaling rules for the DEM force laws. Rapid granular flow from a moving container and angle of repose formation were investigated in order to validate the scheme. The effect of numerical coarse graining was found to be negligible for all properties of interest provided that force laws are scaled properly and corrections for boundary effects are taken into account. The proposed scaling was tested for a certain set of force laws but could be applied to different DEM forces as well.