On the shape of barchan dunes

TL;DR

This paper investigates the shape of barchan dunes using analytical and numerical methods within a minimal model, analyzing how environmental factors influence dune profiles and shape transitions.

Contribution

It introduces an extended minimal model to analytically derive the scale-invariant transverse profile of barchan dunes.

Findings

Dune profiles vary with wind speed and sand supply.

Shape transitions are induced by environmental changes.

Analytical derivation of transverse dune profile.

Abstract

Barchans are crescent-shaped sand dunes forming in aride regions with unidirectional wind and limited sand supply. We report analytical and numerical results for dune shapes under different environmental conditions as obtained from the so-called `minimal model' of aeolian sand dunes. The profiles of longitudinal vertical slices (i.e. along the wind direction) are analyzed as a function of wind speed and sand supply. Shape transitions can be induced by changes of mass, wind speed and sand supply. Within a minimal extension of the model to the transverse direction the scale-invariant profile of transverse vertical cuts can be derived analytically.