Numerical analysis of cohesive granular materials’ flow

Compared to ideal dry granular materials made of perfectly spherical particles, cohesive granular materials flow in a completely different way. We highlight the major features of this specific flow by investigating the effect of cohesion on the flow of granular materials using numerical simulations. We combine a widely-used Discrete Element Method (DEM) with a simplified model of cohesion (i.e. intermediate-range attraction between particles) to reproduce the dynamics of cohesive granular materials in a 2D rotating drum. The resulting flow is analyzed in light of previous experimental and numerical studies in order to validate and calibrate our model. We retrieve the characteristic intermittent flow in avalanches, called plug-flow. We perform a full analysis of the aggregates of particles flowing along the grain-air interface by measuring the velocity profiles, the dynamic angle of repose and by introducing a novel measurement of surface fluctuations. This latter measurement allows us to characterize the size of the aggregates. We show that this measurement could potentially provide the cohesive powders’ microscopic properties in any field of application.