Time resolved particle dynamics in granular convection

TL;DR

This study experimentally investigates the vertical and drift motion of particles in shaken granular layers, revealing the significant role of friction near bifurcation points and challenging existing models.

Contribution

It provides new insights into particle dynamics in granular convection, emphasizing the importance of wall friction and showing limitations of the Inelastic Bouncing Ball Model.

Findings

Particle motion mainly involves vertical jumps and ordered drift.

Friction significantly influences bifurcation behavior.

Wall friction is key to understanding flow dynamics near the lateral wall.

Abstract

We present an experimental study of the movement of individual particles in a layer of vertically shaken granular material. High-speed imaging allows us to investigate the motion of beads within one vibration period. This motion consists mainly of vertical jumps, and a global ordered drift. The analysis of the system movement as a whole reveals that the observed bifurcation in the flight time is not adequately described by the Inelastic Bouncing Ball Model. Near the bifurcation point, friction plays and important role, and the branches of the bifurcation do not diverge as the control parameter is increased. We quantify the friction of the beads against the walls, showing that this interaction is the underlying mechanism responsible for the dynamics of the flow observed near the lateral wall.