Computational simulations of blown sand fluxes over the surfaces of complex microtopography

Studies of sand saltation are currently concentrating on wind tunnel experiments, theoretical analyses and numerical simulations under ideal as well as controllable conditions. These theoretical analyses and numerical simulations cannot accurately predict sand movements in field environments. In this paper, we simulate wind Field patterns for two different surfaces of complex microtopography using the computational fluid dynamic model, FLUENT. To demonstrate that the model can successfully reproduce wind patterns in complex microtopography, we first simulate a well-studied mesquite bush and coppice dune field from the Chihuahuan Desert. This is then followed by an analysis of the wind field pattern around a large barchan dune that is complex in shape. For this case, the wind pattern was linked with a sediment transport equation to estimate sediment flux and transport. Finally, as shown by the simulation results, the sand flux, from the right horn to the left horn of the dune, first increased then decreased after reaching its maximum at the intersection of the brink and the longitudinal centreline of the dune. (C) 2009 Elsevier Ltd. All rights reserved.