Collapse of Granular Columns: Simulation for Typical Doubly Connected Structures

With varying column confining geometry, we investigated annular granular column collapses and related the influence of the shape of confining geometry on the dynamics of flow. A prior study that focused only on initially circular topologies observed the significance of collapse studies of granular columns and came to the conclusion that the distance traveled by the final deposit is correlated with the aspect ratio of the granular column. This work simulates granular columns with two different initial column cross-section types, square and equilateral triangular, using the discrete element method (DEM). The effect of confining walls and confining geometry on the collapse has been presented. The study reveals the dependence of run-out distances on non-circular doubly connected cross-sections. Instead of one (in the case of circular geometry), two flow fronts have been observed, one in the vertex direction and the other in the edge direction. Also, a central jet has been observed due to inner flow front propagation. In conclusion, a general relationship is suggested that considers the cross-section influence.