Slowly Driven Sandpile Formation with Granular Mixtures

TL;DR

This paper introduces a one-dimensional granular mixture sandpile model with multiple particle types, revealing diverse structural classes and analyzing their behaviors under different parameters, with implications for experimental validation.

Contribution

It presents a novel multi-type particle sandpile model with a detailed classification of structural behaviors for N=2 and their combinations for larger N, expanding understanding of granular mixture dynamics.

Findings

Four classes of sandpile structures identified for N=2.

Behavior for N>2 is a combination of these classes.

Model robustness and experimental focus areas discussed.

Abstract

We introduce a one-dimensional sandpile model with $N$ different particle types and an infinitesimal driving rate. The parameters for the model are the N^2 critical slopes for one type of particle on top of another. The model is trivial when N=1, but for N=2 we observe four broad classes of sandpile structure in different regions of the parameter space. We describe and explain the behaviour of each of these classes, giving quantitative analysis wherever possible. The behaviour of sandpiles with N>2 essentially consists of combinations of these four classes. We investigate the model's robustness and highlight the key areas that any experiment designed to reproduce these results should focus on.