Granular flows in rotating drums are central to both industrial processes and natural phenomena. While most studies have focused on spherical particles, many real systems involve angular grains whose geometry alters flow behavior. We present a combined experimental and numerical investigation of frictional pyramid-shaped particles in drums of varying widths and rotation speeds. Laboratory experiments were complemented by discrete element method (DEM) simulations using polyhedral representations of pyramids. Flow regimes (rolling, cascading, cataracting) were systematically characterized, and regime transitions were mapped as functions of drum thickness and angular velocity. Results show that narrower drums amplify confinement effects, increasing mean surface angles and fluctuations, while pyramidal particles exhibit enhanced interlocking, and more homogeneous flows compared to spheres at high rotation speeds. Avalanche and repose angles were also determined, confirming that angular particles yield significantly larger values. Overall, DEM simulations reproduce experimental observations with quantitative fidelity, validating pyramids as a robust model system for shape-induced granular dynamics. • Pyramidal particle flow is studied via experiments and DEM simulations. • High rotation speeds attenuate shape effects by reducing packing fraction. • Characteristic widths are significantly larger than for spherical grains. • Flow regime transitions are mapped for various drum widths and speeds.
Mahmoud et al. (Fri,) studied this question.