Flow of anisometric particles in a quasi-2D hopper

TL;DR

This study experimentally examines how anisometric particles, like elongated grains, flow in a quasi-2D hopper, revealing differences in velocity profiles and fluctuations compared to spherical beads, with implications for granular flow modeling.

Contribution

It provides the first detailed comparison of flow behavior between spherical and elongated particles in a quasi-2D hopper, highlighting shape-dependent flow characteristics.

Findings

Gaussian velocity profile fits for beads

Narrower flow channel for elongated grains

Larger and slower velocity fluctuations for elongated particles

Abstract

The stationary flow field in a quasi-two-dimensional hopper is investigated experimentally. The behavior of materials consisting of beads and elongated particles with different aspect ratio is compared. We show, that while the vertical velocity in the flowing region can be fitted with a Gaussian function for beads, in the case of elongated grains the flowing channel is narrower and is bordered with sharper velocity gradient. For this case, we quantify deviations from the Gaussian velocity profile. Relative velocity fluctuations are considerably larger and slower for elongated grains.