Reorganization of a granular medium around a localized transformation

TL;DR

This study investigates the structural reorganization of a 2D granular medium around localized transformations, revealing avalanche-like dynamics, self-similar distributions, and a unified rearrangement mechanism.

Contribution

It provides experimental insights into the rearrangement dynamics of granular media during localized transformations, highlighting avalanche behavior and self-similarity.

Findings

Avalanche-like events follow power-law distributions.

Local solid fraction variations exhibit self-similar distributions.

Rearrangement mechanisms can be unified through rescaling of data.

Abstract

Physical and chemical transformation processes in reactive granular media involve the reorganization of the structure. In this paper, we study experimentally the rearrangements of a two-dimensional (2D) granular packing undergoing a localized transformation. We track the position and evolution of all the disks that constitute the granular packing when either a large intruder shrinks in size or is pulled out of the granular structure. In the two situations the displacements at long time are similar to 2D quasistatic silo flows whereas the short-time dynamic is heterogeneous in both space and time. We observe an avalanchelike behavior with power-law distributed events uncorrelated in time. In addition, the instantaneous evolutions of the local solid fraction exhibit self-similar distributions. The averages and the standard deviations of the solid fraction variations can be rescaled, suggesting a single mechanism of rearrangement.