The growth of a Super Stable Heap : an experimental and numerical study

TL;DR

This paper investigates the growth dynamics of super stable heaps in granular flows through combined experimental, numerical, and theoretical approaches, revealing how flow rate and layer height influence heap stability and growth rate.

Contribution

It introduces a theoretical model linking growth rate to grain exchange and confirms it with experiments and simulations, enhancing understanding of super stable heap formation.

Findings

Growth rate proportional to flowing layer height.

Model accurately predicts heap evolution.

Upstream waves provide new insights into BCRE model.

Abstract

We report experimental and numerical results on the growth of a super stable heap (SSH). Such a regime appears for flows in a thin channel and for high flow rate : the flow occurs atop a nearly static heap whose angle is stabilized by the flowing layer at its top and the side wall friction. The growth of the static heap is investigated in this paper. A theoretical analysis inspired by the BRCE formalism predicts the evolution of the growth process, which is confirmed by both experiments and numerical simulations. The model allows us to link the characteristic time of the growth to the exchange rate between the "moving" and "static" grains. We show that this rate is proportional to the height of the flowing layer even for thick flows. The study of upstream traveling waves sheds new light on the BCRE model.