Grain size dependence of barchan dune dynamics

TL;DR

This study experimentally explores how grain size influences barchan dune dynamics, revealing that dune velocity and relaxation time depend on grain size, while shape and velocity scaling do not.

Contribution

It provides new experimental insights into the effects of grain size on dune relaxation time and velocity, clarifying their roles in dune dynamics.

Findings

Relaxation time increases with dune mass and decreases with grain size.

Dune velocity increases with grain size.

Shape and velocity scaling are independent of grain size.

Abstract

The dependence of the barchan dune dynamics on the size of the grains involved is investigated experimentally. Downsized barchan dune slices are observed in a narrow water flow tube. The relaxation time from an initial symmetric triangular heap towards an asymmetric shape attractor increases with dune mass and decreases with grain size. The dune velocity increases with grain size. In contrast, the velocity scaling and the shape of the barchan dune is independent of the size of the grains.