Unified power-law scaling behavior of collapse mobility and deposition morphology of granular columns composed of frictional-pentagonal grains

This paper carries out extensive simulations of granular columns composed of frictional-pentagonal grains, collapsing on a horizontal plane. Various two-dimensional columns are used and the interparticle friction coefficient is systematically varied in a broad range of values, aiming to comprehensively highlight and universally describe the runout distance, deposition height, area of top-deposition surface, kinetic energy, and apparent friction coefficient. We show that these physical quantities observed in the current work are consistent with previous findings and are affected by the degrees that depend differently on the initial column aspect ratio and interparticle friction coefficient. Remarkably, we nontrivially unveil a unified power-law scaling behavior for runout distance, deposition height, area of top-deposition surface, kinetic energy, and apparent friction coefficient by defining an effective aspect ratio, inversely incorporating the complex competition between initial aspect ratio and interparticle friction coefficient. This universal power-law description may confirm a unified competition of frictional and inertial effects on geophysical mass flows, providing a better understanding of the behavior of natural hazards such as rock avalanches and landslides.