Acoustic resonances in a confined set of macroscopic disks

TL;DR

This study investigates acoustic resonances in a dense granular disk system confined in a rectangle, analyzing how different interparticle potentials affect signal transmission and anisotropy, using simulations and eigenfrequency analysis.

Contribution

It provides a comparative analysis of acoustic resonances in granular disks with different potentials, highlighting the impact on signal transmission and anisotropic behaviors.

Findings

Signal transmission varies significantly with interaction models.

Strong anisotropies can emerge depending on interparticle forces.

Eigenfrequency spectra are analytically and numerically consistent.

Abstract

We study in this work a system of granular disks enclosed in a rectangular region. Granular disks are arranged, at high particle density, in a hexagonal lattice. Specifically, we are interested in the conditions for mechanical signal transmission. Two different potentials are considered. Our results are obtained by means of soft disks computer simulations. We analytically determine the eigenfrequencies spectra of the system from the corresponding Hessian matrix. Alternatively, the eigenfrequencies can also be obtained from the time evolution of molecular dynamics simulations. Previous works have shown that mechanical signal transmission in granular matter can be used to develop acoustic switches. Our results reveal that the working range of the granular switch changes dramatically for different interaction models. In particular, strong anisotropies in signal transmission may appear for certain interparticle forces.