UCL Discovery

Abstract

Many natural hazards and industrial processes involve the collapse of granular particles onto a horizontal plane. Recent researches have studied the fundamental physics of the collapse of granular columns in experimental and numerical approaches. This paper presents a three-dimensional discrete element simulation of the axisymmetric spreading of initially vertical granular columns, in which the runout of the grains and their dynamic motion are continuously monitored during the course of collapse. Using a polar coordinate method to quantify the spread of the grains, the numerical results are in good agreement with previous research findings. The collapse dynamics is shown to be dependent on the initial geometry of the cylindrical column and independent of the inter-granular friction. Two distinct flow regimes are observed: a linear scaling and a power-law scaling are derived for the final runout distances of the columns. The problem is further explored by studying the effects of coefficient of restitution on the runout mechanics, in which energy dissipation at collisions has played an important role in determining the runout of the system.