Fluctuations of grains inside a discharging two-dimensional silo

TL;DR

This paper investigates the microscopic velocity fluctuations in a two-dimensional granular flow during silo discharge, providing experimental data to evaluate existing models and analyze advective and diffusive motion behaviors.

Contribution

It offers new experimental insights into grain velocity fluctuations and assesses the validity of traditional approaches in describing granular flow in silos.

Findings

Velocity profiles obtained from particle tracking

Nontrivial behavior of velocity fluctuations

Assessment of long-standing modeling approaches

Abstract

We present experimental data corresponding to a two dimensional dense granular flow, namely, the gravity-driven discharge of grains from a small opening in a silo. We study the microscopic velocity field with the help of particle tracking techniques. From these data, the velocity profiles can be obtained and the validity of some long-standing approaches can be assessed. Moreover, the fluctuations of the velocities are taken into consideration in order to characterize the features of the advective motion (due to the gravity force) and the diffusive motion, which shows nontrivial behaviour.