# Kinetically constrained model for gravity-driven granular flow and clogging

## TL;DR

This paper introduces a kinetically constrained lattice-gas model with gravity to study dense granular flow and clogging, revealing how current behavior varies with density and field intensity, including jamming phenomena.

## Contribution

It extends the Kob-Andersen model by incorporating gravity effects and analyzes flow and clogging behavior at different densities, providing theoretical and simulation insights.

## Key findings

- Current matches mean field theory at low densities.
- Non-monotonic current dependence on field at intermediate densities.
- Flow through a narrow hole agrees with theoretical predictions.

## Abstract

We add extreme driving to the Kob-Andersen kinetically-constrained lattice-gas model in order to mimic the effect of gravity on dense granular systems. For low particle densities, the current that develops in the system agrees at arbitrary field intensity with a mean field theory. At intermediate densities, spatial correlations give rise to non-monotonic dependence of the current on field intensity. At higher densities, the current ultimately vanishes at a finite, field-dependent jamming density. We supplement the study of this bulk behavior with an investigation of the current through a narrow hole. There, lateral flow decreases the local density in front of the hole. Remarkably, the current through the hole quantitatively agrees with a theoretical prediction based on the bulk current at the measured local density.