Granular Pressure and the Thickness of a Layer Jamming on a Rough Incline

TL;DR

This paper investigates how the pressure in dense granular layers on rough inclines can be inferred from the residual layer thickness after flow cessation, offering a new experimental approach to understanding granular pressure in frozen states.

Contribution

It introduces a novel method to measure granular pressure in dense, flowing, and frozen states using residual layer thickness after flow stops.

Findings

Residual layer thickness correlates with granular pressure.

Flowing states can be used to explore granular microstates.

Proposed method provides new insights into granular compaction.

Abstract

Dense granular media have a compaction between the random loose and random close packings. For these dense media the concept of a granular pressure depending on compaction is not unanimously accepted because they are often in a "frozen" state which prevents them to explore all their possible microstates, a necessary condition for defining a pressure and a compressibility unambiguously. While periodic tapping or cyclic fluidization have already being used for that exploration, we here suggest that a succession of flowing states with velocities slowly decreasing down to zero can also be used for that purpose. And we propose to deduce the pressure in \emph{dense and flowing} granular media from experiments measuring the thickness of the granular layer that remains on a rough incline just after the flow has stopped.