Coarsening Dynamics of Granular Heaplets in Tapped Granular Layers

TL;DR

This paper introduces a semi-continuum model to study the formation and coarsening of granular heaplets in tapped layers, highlighting the effects of energy dissipation, screening, and tapping intensity on pattern dynamics.

Contribution

The study presents a novel semi-continuum model that captures the coarsening dynamics and effective surface tension of granular heaplets under tapping, with insights into the influence of tapping intensity.

Findings

Heaplets exhibit an effective surface tension dependent on tapping intensity.

The average size of heaplets grows with the number of taps following a power law.

The growth exponent diverges as tapping intensity increases.

Abstract

A semi-continuum model is introduced to study the dynamics of the formation of granular heaplets in tapped granular layers. By taking into account the energy dissipation of collisions and screening effects due to avalanches, this model is able to reproduce qualitatively the pattern of these heaplets. Our simulations show that the granular heaplets are characterised by an effective surface tension which depends on the magnitude of the tapping intensity. Also, we observe that there is a coarsening effect in that the average size of the heaplets, V grows as the number of taps k increases. The growth law at intermediate times can be fitted by a scaling function V ~ k^z but the range of validity of the power law is limited by size effects. The growth exponent z appears to diverge as the tapping intensity is increased.