Long-range interactions in randomly driven granular fluids

TL;DR

This paper investigates how long-range correlations and effective interactions emerge in a nonequilibrium granular fluid driven randomly, highlighting the influence of boundary conditions and confirming predictions with simulations.

Contribution

It provides explicit analytical forms of static structure factors and demonstrates how boundary conditions affect effective forces between intruders in granular fluids.

Findings

Analytical structure factors match simulation results.

Boundary shape and orientation influence effective forces.

Long-range interactions arise from confinement of fluctuation spectra.

Abstract

We study the long-range spatial correlations in the nonequilibrium steady state of a randomly driven granular fluid with the emphasis on obtaining the explicit form of the static structure factors. The presence of immobile particles immersed in such a fluidized bed of fine particles leads to the confinement of the fluctuation spectrum of the hydrodynamic fields, which results in effective long-range interactions between the intruders. The analytical predictions are in agreement with the results of discrete element method simulations. By changing the shape and orientation of the intruders, we address how the effective force is affected by small changes in the boundary conditions.