Avalanche Interpretation of the Power-Law Energy Spectrum in Three-Dimensional Dense Granular Flow

TL;DR

This paper investigates the turbulent-like energy spectrum in three-dimensional dense granular flows, revealing significant differences from 2D flows and linking avalanche dynamics to these dimensional effects.

Contribution

It demonstrates that 3D granular flows exhibit unique statistical behaviors and structures, explained by avalanche dynamics, and introduces particle clusters analogous to vortex filaments.

Findings

3D flows show different energy spectrum characteristics than 2D flows.

Avalanche dynamics explain the dimensionality dependence.

Clusters of particles reveal complex structures absent in 2D flows.

Abstract

Turbulence is ubiquitous in nonequilibrium systems, and it has been noted that even dense granular flows exhibit characteristics that are typical of turbulent flow, such as the power-law energy spectrum. However, studies on the turbulent-like behavior of granular flows are limited to two-dimensional (2D) flow. We demonstrate that the statistics in three-dimensional (3D) flow are qualitatively different from those in 2D flow. We also elucidate that avalanche dynamics can explain this dimensionality dependence. Moreover, we define clusters of collectively moving particles that are equivalent to vortex filaments. The clusters unveil complicated structures in 3D flows that are absent in 2D flows.