Crucial role of sidewalls in velocity distributions in quasi-2D granular gases

TL;DR

This study combines experiments and simulations to show that sidewall interactions significantly influence the velocity distribution in quasi-2D granular gases, affecting their non-Gaussian features.

Contribution

It demonstrates the crucial impact of sidewall friction on velocity distributions, highlighting the importance of container interactions in confined granular systems.

Findings

Frictional sidewalls produce peaked velocity distributions.

Frictionless sidewalls result in non-peaked distributions.

Container interactions are key in shaping velocity profiles.

Abstract

Our experiments and three-dimensional molecular dynamics simulations of particles confined to a vertical monolayer by closely spaced frictional walls (sidewalls) yield velocity distributions with non-Gaussian tails and a peak near zero velocity. Simulations with frictionless sidewalls are not peaked. Thus interactions between particles and their container are an important determinant of the shape of the distribution and should be considered when evaluating experiments on a tightly constrained monolayer of particles.