Dunes, the Collective Behaviour of Wind and Sand, or: Are Dunes Living Beings?

Abstract

According to the dictionary, a dune is “a mound or ridge of wind-blown sand”. But the shape of a dune is more than just a “mound”, even if it is often difficult to interpret the contours at first glance. Expanses of dunes are often compared to the sea. Firstly because of the multitude of crests, so similar to waves. But also because, just like waves, we sense intuitively that sand dunes are in movement, and it is their movement that determines their form. For if you look closer, the shape of dunes is not so random … But how can we describe this shape, understand it, determine its origin and dynamics? How can we bring to light the logic that links these forms to the countless grains of sand swept up by the wind, or understand what it is that gives this collective phenomenon its coherence?