Velocity Distributions & Density Fluctuations in a 2D Granular Gas

TL;DR

This study experimentally examines velocity distributions in a vibrated 2D granular monolayer, revealing a transition from non-Gaussian to Gaussian distributions with increased vibration amplitude and highlighting the role of density fluctuations.

Contribution

It provides new insights into how vibration amplitude influences velocity distribution shapes and the correlation with density fluctuations in granular gases.

Findings

Non-Gaussian velocity distributions at low vibration amplitudes.

Smooth transition to Gaussian distributions as amplitude increases.

Persistent non-Gaussian distributions under confinement.

Abstract

Velocity distributions in a vibrated granular monolayer are investigated experimentally. Non-Gaussian velocity distributions are observed at low vibration amplitudes but cross over smoothly to Gaussian distributions as the amplitude is increased. Cross-correlations between fluctuations in density and temperature are present only when the velocity distributions are strongly non-Gaussian. Confining the expansion of the granular layer results in non-Gaussian velocity distributions that persist to high vibration amplitudes.