Velocity distribution of a homogeneously driven two-dimensional granular gas

TL;DR

This paper experimentally confirms the theoretical prediction that a homogeneously driven two-dimensional granular gas exhibits a power-law velocity distribution with overpopulated high-energy tails, aligning with prior numerical simulations.

Contribution

It provides the first experimental evidence supporting the theoretical velocity distribution predictions for driven granular gases using self-rotating active particles.

Findings

Velocity distribution follows a power-law decay.

Experimental results agree with theoretical predictions.

High-energy tails are overpopulated compared to exponential decay.

Abstract

The theory of homogeneously driven granular gases of hard particles predicts that the stationary state is characterized by a velocity distribution function with overpopulated high-energy tails as compared to the exponential decay valid for molecular gases. While this fundamental theoretical result was confirmed by numerous numerical simulations, an experimental confirmation is still missing. Using self-rotating active granular particles, we find a power-law decay of the velocity distribution whose exponent agrees well with the theoretic prediction.