Creep motion of a granular pile induced by thermal cycling

TL;DR

This study investigates how thermal cycling induces slow, complex motion in granular piles, revealing continuous settling at large amplitudes and intermittent collapses at smaller amplitudes, with implications for understanding granular dynamics.

Contribution

It provides a detailed time-resolved analysis of granular pile behavior under thermal cycles, highlighting the transition between continuous and intermittent motion based on cycle amplitude.

Findings

Large amplitude cycles cause continuous settling.

Small amplitude cycles lead to intermittent collapses.

Collapse durations follow an exponential distribution.

Abstract

We report a time-resolved study of the dynamics associated with the slow compaction of a granular column submitted to thermal cycles. The column height displays a complex behavior: for a large amplitude of the temperature cycles, the granular column settles continuously, experiencing a small settling at each cycle; By contrast, for small-enough amplitude, the column exhibits a discontinuous and intermittent activity: successive collapses are separated by quiescent periods whose duration is exponentially distributed. We then discuss potential mechanisms which would account for both the compaction and the transition at finite amplitude.