Dynamical compressibility of dense granular shear flows

TL;DR

This paper demonstrates through simulations that dense granular shear flows exhibit dynamical compressibility, supporting the idea that such systems can support transverse and sagittal waves related to their pressure-dependent density.

Contribution

The study provides the first direct evidence of wave phenomena linked to dynamical compressibility in dense granular flows using discrete element simulations.

Findings

Existence of transverse and sagittal waves in dense granular flows

Resonance of these waves observed in a linear Couette cell

Results align with continuum local constitutive relation

Abstract

It has been conjectured by Bagnold [1] that an assembly of hard non-deformable spheres could behave as a compressible medium when slowly sheared, as the average density of such a system effectively depends on the confining pressure. Here we use discrete element simulations to show the existence of transverse and sagittal waves associated to this dynamical compressibility. For this purpose, we study the resonance of these waves in a linear Couette cell and compare the results with those predicted from a continuum local constitutive relation.