title: Column collapse of granular rods.
abstract: We investigate the collapse of granular rodpiles as a function of particle (length/diameter) and pile (height/radius) aspect ratio. We find that, for all particle aspect ratios below 24, there exists a critical height Hl below which the pile never collapses, maintaining its initial shape as a solid, and a second height Hu above which the pile always collapses. Intermediate heights between Hl and Hu collapse with a probability that increases linearly with increasing height. The linear increase in probability is independent of particle length, width, or aspect ratio. When piles collapse, the runoff scales as a piecewise power law with pile height, with rf ~H(1.2±0.1) for pile heights below H(c) ≈ 0.74 and r(f) ≈ H(0.6±0.1) for taller piles.
authors.affiliation: Department of Physics, Rochester Institute of Technology, Rochester, New York 14623, USA.
authors.forename: M
authors.initials: M
authors.lastname: Trepanier
authors.forename: Scott V
authors.initials: SV
authors.lastname: Franklin