This study introduces a mathematical model to predict the dynamic angle of repose exhibited by granular materials in a rotating drum. The model accounts for the effect of particle properties, particularly sliding and rolling friction, as well as process conditions, i.e., the Froude number. We show that the effects of particle properties can be modeled independently of the process conditions, resulting in a multiplicative model. The model is validated using experimental data taken at different Froude numbers, yielding favorable agreement between the predicted dynamic angle of repose and the experimental observations. The findings of this study hold significant implications for engineering disciplines, as they provide crucial insights for optimizing processes involving granular materials in various engineering applications.

In this paper we introduce the open-source code MercuryDPM: a code for simulating discrete particles. The paper discusses software and management issues that may be interesting for the developers of other open-source codes. Then we review the new features that have been added since the last publication: an improved Hertz-Mindlin model; a new liquid bridge model of Lian and Seville; a droplet-spray model; better support for re-creating complex, measured particle size distributions; a new implementation of rigid clumps; an implementation of elastic membranes; a wear model for walls; a soft-kill feature and a cloud-deployment interface for AWS.