RESEARCH ARTICLE

Granular avalanche statistics in rotating drum with varied particle roughness

¹ School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
² State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China
³ Department of Physics, College of Mathematics and Physics, Chengdu University of Technology, Chengdu 610059, China

^* Corresponding authors (emails: yuanyeoct20@sjtu.edu.cn (Ye Yuan); yujiewang@sjtu.edu.cn (Yujie Wang))

Received: 9 December 2022
Revised: 22 February 2023
Accepted: 16 March 2023

Abstract

We experimentally investigate the avalanche statistics of dry granular materials in a slowly rotating drum for five types of beads with varied surface roughness. For all beads, two distinct angles, i.e., repose angle θ_r and maximal angle θ_m, can be clearly defined, and the avalanche size distributions P(δθ) are Gaussian-like. θ_r, θ_m, and the span in P(δθ) are all positively correlated with bead surface roughness. This observation thus contrasts with a power-law P(δθ) predicted by self-organized criticality, but is reminiscent of a first-order phase transition. We speculate that both the inertia effect and the velocity-weakening mechanism during an avalanche process can enhance the first-order features, which are however absent in plasticity of sheared amorphous solids. We also discuss the dependence between θ_r and θ_m for various particles, as well as the correlation between starting and stopping angles for an individual avalanche.