Segregation and Stability of Binary Granular Mixtures

TL;DR

This study investigates how grain size and configuration affect the stability of granular mixtures in a rotating drum, revealing that smaller grains tend to cluster centrally and significantly influence heap stability.

Contribution

It demonstrates the relationship between grain segregation patterns and stability, highlighting the impact of grain configuration on the maximum stability angle.

Findings

Smaller, smoother grains cluster near the center, larger, rougher grains near the edge.

Maximum stability angle varies non-linearly with composition, especially when small grains are added.

Central grain configuration plays a key role in heap stability.

Abstract

We measure stability of two-dimensional granular mixtures in a rotating drum and relate grain configurations to stability. For our system, the smaller but smoother grains cluster near the center of the drum, while the larger, rougher grains remain near the outer edge. One consequence of the size segregation is that the smaller grains heavily influence the stability of the heap. We find that the maximum angle of stability is a non-linear function of composition, changing particularly rapidly when small grains are first added to a homogeneous pile of large grains. We conclude that the grain configuration within the central portion of the heap plays a prominent role in stability.