Column collapse of granular rods

Area of Science:

• Physics
• Materials Science
• Granular Mechanics

Background:

• Understanding granular material behavior is crucial in various scientific and engineering fields.
• The collapse dynamics of granular piles are influenced by particle shape and pile geometry.
• Rod-shaped particles present unique challenges in predicting pile stability.

Purpose of the Study:

• To investigate the collapse behavior of granular rod piles.
• To determine the influence of particle aspect ratio and pile dimensions on collapse.
• To characterize the runoff scaling after pile collapse.

Main Methods:

• Experimental investigation of granular rod piles with varying particle and pile aspect ratios.
• Systematic measurement of critical collapse heights (Hl and Hu).
• Analysis of collapse probability as a function of pile height.
• Quantification of runoff volume and its scaling with pile height.

Main Results:

• A critical height (Hl) below which piles are stable and a height (Hu) above which they always collapse were identified.
• Collapse probability increases linearly with pile height for intermediate heights, independent of particle shape.
• Runoff scales as a piecewise power law with pile height, with different exponents for shorter and taller piles.

Conclusions:

• Granular rod pile collapse is governed by critical height thresholds.
• The linear probability of collapse suggests a universal mechanism for intermediate heights.
• The piecewise power-law scaling of runoff provides insights into granular flow dynamics.