Lattice Gas Cellular Automaton Dune Model

In the last decades, different scientists have explored a variety of CA approach in order to model dune features in arid desert on Earth. In all cases, despite a stochastic ingredient, the trajectory of an elementary volume of grains does not dissociate transport, erosion and deposition processes. In addition, there is no treatment of aerodynamics effect. In our CA model for sediment transport, individual physical processes such as erosion, deposition and transport are implemented by nearest neighbor interactions and a time-dependent stochastic process. Simultaneously, a lattice gas CA model is used to compute the flow and quantify the bed shear stress on the topography. Then, the dependence of the erosion rate on the bed shear stress as well as the rebounds dynamics of fluid particles on sedimentary cells ensure permanent feedback mechanisms between flow and topography (see Narteau et al. 2009).


Barchan dunes are isolated structures with horns extending downwind on both sides of a sand pile characterized by a slip face and a windward face. From outputs of the model, we study the mechanics of an individual barchan dune under a variety of wind conditions and the dynamic of a population of dunes in response to variation in sand availability. To facilitate our work, we develop different numerical tools that allow calculating the evolution of the frequency-size relationship as well as the grain flux perpendicularly to the flow during our computations.

                    Dunes in arid desert on Earth
                                        Dunes in the model    (click on the pictures for movies)


                                                    Formation and evolution of an individual barchan dune

                 Transverse Dunes                                                           Formation and evolution of a population of barchan dunes