Collective Effects in the Horizontal Transport of Vertically Vibrated Granular Layers

TL;DR

This study investigates how granular particles move horizontally in a vertically vibrated system with a sawtooth base, revealing collective behaviors like current reversal and phase-transition-like onset of transport.

Contribution

It provides experimental and simulation evidence of collective effects and transport reversals in vibrated granular layers with complex base profiles.

Findings

Current reversal with increasing layer thickness

Transport onset can be gradual or abrupt

Behavior depends on particle number and driving frequency

Abstract

Motivated by recent advances in the investigation of fluctuation-driven ratchets and flows in excited granular media, we have carried out experimental and simulational studies to explore the horizontal transport of granular particles in a vertically vibrated system whose base has a sawtooth-shaped profile. The resulting material flow exhibits novel collective behavior, both as a function of the number of layers of particles and the driving frequency; in particular, under certain conditions, increasing the layer thickness leads to a reversal of the current, while the onset of transport as a function of frequency can occur either gradually or suddenly in a manner reminiscent of a phase transition.