Energy Dissipation in Driven Granular Matter in the Absence of Gravity

TL;DR

This study experimentally examines energy dissipation in granular materials under sinusoidal driving in weightless conditions, revealing two dynamic regimes with distinct dissipation mechanisms and scaling behaviors.

Contribution

It identifies and characterizes two regimes of granular dynamics under driven conditions in weightlessness, providing a unified model for granular damping behavior.

Findings

Two regimes: collect-and-collide and gas-like behavior.

Different scaling laws for energy dissipation in each regime.

A unified curve describes the physics of granular dampers.

Abstract

We experimentally investigate the energy dissipation rate in sinusoidally driven boxes which are partly filled by granular material under conditions of weightlessness. We identify two different modes of granular dynamics, depending on the amplitude of driving, $A$. For intense forcing, A>A_0, the material is found in the collect-and-collide regime where the center of mass of the granulate moves synchronously with the driven container while for weak forcing, A<A_0, the granular material exhibits gas-like behavior. Both regimes correspond to different dissipation mechanisms, leading to different scaling with amplitude and frequency of the excitation and with the mass of the granulate. For the collect-and-collide regime, we explain the dependence on frequency and amplitude of the excitation by means of an effective one-particle model. For both regimes, the results may be collapsed to a single curve characterizing the physics of granular dampers.