ABSTRACT
A DEM model and a MDEM (modified DEM) model including additional parameters to take into account a rolling resistance at particles contact, are compared. The influence of rolling resistance on granular flow during the discharge of a flat-bottomed silo is analyzed using 2D discrete simulations. A slender rectangular silo of 22 m height filled by 10,000 particles is considered. The results show that the two methods give different flow patterns. In DEM, shear bands are localized along the vertical walls and the stagnant zones. MDEM produces a block-like flow with high arching effects. Discontinuities between blocks are observed in the converging zone above the outlet where arc-shaped shear bands are clearly seen, and in the middle height of the silo separating two distinct moving zones. If DEM looks representative of idealized granular media, MDEM appears more adequate for modeling the behavior of natural granular materials.
