Velocity correlations in dense granular flows

TL;DR

This study experimentally investigates velocity fluctuations in dense granular flows on inclined planes, revealing a correlation length influenced by inclination angle, suggesting flow dynamics are governed by a characteristic length scale larger than individual grains.

Contribution

It demonstrates that the velocity correlation length in dense granular flows depends on inclination angle, not layer thickness, highlighting a characteristic length scale beyond individual particles.

Findings

Correlation length depends on inclination angle

Velocity fluctuations are correlated over a few grain diameters

Flow dynamics are governed by a characteristic length larger than a single grain

Abstract

Velocity fluctuations of grains flowing down a rough inclined plane are experimentally studied. The grains at the free surface exhibit fluctuating motions, which are correlated over few grains diameters. The characteristic correlation length is shown to depend on the inclination of the plane and not on the thickness of the flowing layer. This result strongly supports the idea that dense granular flows are controlled by a characteristic length larger than the particle diameter.