The study investigates the shearing of granular rods in split-bottom setups, revealing that a notable heap can form at the surface, reaching at least 40% of the filling height.
The heaping phenomenon is attributed to a significant secondary flow that does not occur with spherical particles, and flow reversal affects this secondary flow, causing quick collapses and slower heap regenerations.
The research posits that a misalignment between the average orientation of the particles and the flow streamlines drives the secondary flow, implying this mechanism is relevant for flows involving other anisometric grains.