Modelling transverse dunes

Transverse duties appear in regions of mainly unidirectional wind and high sand availability. A dune model is extended to two-dimensional calculation of the shear stress. It is applied to simulate dynamics and morphology of three-dimensional transverse dunes. In the simulations they seem to reach translational invariance and do not stop growing. Hence, simulations of two-dimensional dune fields have been performed. Characteristic laws were found for the time evolution of transverse dunes. Bagnold's law of the dune velocity is modified and reproduced. The interaction between transverse dunes led to the interesting conclusion that small duties can travel over bigger ones. Copyright (C) 2004 John Wiley Sons, Ltd.