A Simple Agent‐Based Model That Reproduces All Types of Barchan Interactions
Dominic T. Robson, Andreas Baas
Abstract
Abstract We introduce a novel agent‐based model for simulating interactions between migrating barchan dunes. A new two‐flank representation of barchans allows modeling of bedform asymmetries that are intrinsic to collision dynamics but have not been explored before. Although simple compared with real‐world barchans or those in continuum and cellular automata simulations, all known barchan behaviors emerge from the rules of our model. In particular, the two mechanisms for asymmetry growth in bimodal winds are observed and qualitatively agree with existing theories. We also reproduce the emergence of calving and all types of collisions that have been reported in reductionist models, water‐tank experiments, and field observations. The computational efficiency of the new model, compared with continuum simulations, enables the simulation of large swarms of dunes while maintaining the complex phenomenology of these bedforms, some of which has been lacking in previous agent‐based models.