Numerical experiments into particle shape effects on immersed granular column collapse

Granular flows, driven by shear (e.g., sediment transport) or gravity (e.g., pyroclastic flows, landslides, avalanches), are significantly influenced by particle density, size, and shapes. In this study, we pander to gravity-driven granular flows, specifically channelized granular column collapse, using particle-resolved simulations via an immersedboundary method. We systematically investigate the effects of particle shape (sphere, spheroid, and their mixture) on granular column collapse. For spheroids, we vary the aspect ratio from minor to major axis radius to study the

effect on overall granular collapse phenomenon. We also examine the impact of size and density with different shapes to isolate the level of segregation during collapse. Present investigations are restricted to the ‘inertial regime’ with St/X≥2.5 and X≤4 (where St is the Stokes number and X is the particle to fluid density ratio). Comparison of the final deposit shapes and extents among different initial height to width ratio aspect ratios of the column is performed, and the potential and kinetic energy budget evolution is analyzed. Furthermore, segregation level for the final extent of the column with respect to the initial aspect ratio is examined.