Our new paper, Collapse dynamics of two-dimensional dry and immersed granular columns of elongated grains, has been published in Physical Review Fluids!
The collapse dynamics and runout of columns of elongated grains in two dimensions are
numerically investigated in dry and immersed conditions, by means of an unresolved finite
elements/discrete elements model. The elongated grains are modeled as rigid aggregates
of disks. The column aspect ratio is systematically varied from 0.125 to 16 in order
to span short and tall columns. To analyze the effect of the initial grain orientation,
columns with an initial grain orientation that is either random or aligned with a given
direction are both considered. Collapse dynamics, both in dry and immersed cases, are
found analogous to that previously observed for circular grain columns, particularly with
respect to the power law dependency for the runout as a function of the column aspect
ratio. The effect of the fluid mainly results in a decrease of the runout distance. Inter-
estingly, the collapse dynamics and runout are not significantly affected by the initial
orientation of the grains, except maybe in the extreme case where the grains are all
horizontally oriented, which geometrically prevents the collapse. Finally, a scaling based
on the front propagation energy is proposed allowing one to unify the runout of short to
tall and dry to immersed columns in a single description, regardless of the initial grain
orientation.
For more details, check the publications section!