Speckle visibility spectroscopy and variable granular fluidization

TL;DR

This paper presents a novel dynamic light scattering method using speckle visibility to measure rapid, systematic changes in granular materials, revealing transitions and jamming behavior in vibrated glass beads.

Contribution

It introduces a new speckle visibility spectroscopy technique for analyzing dynamic granular systems and characterizes temperature variations and jamming transitions during vibration cycles.

Findings

Measured granular temperature variation with phase in oscillation

Identified transitions involving jammed states

Observed two-step decay of temperature near jamming

Abstract

We introduce a dynamic light scattering technique capable of resolving motion that changes systematically, and rapidly, with time. It is based on the visibility of a speckle pattern for a given exposure duration. Applying this to a vibrated layer of glass beads, we measure the granular temperature and its variation with phase in the oscillation cycle. We observe several transitions involving jammed states, where the grains are at rest during some portion of the cycle. We also observe a two-step decay of the temperature on approach to jamming.