Abstract
Basically, sand dunes are patterns resulting from the coupling of
hydrodynamic and sediment transport. Once grains move, they modify the
surface topography which in turns modifies the flow. This important
feedback mechanism lies at the core of continuous dune modelling. Here
we present an updated review of such a model for aeolian dunes,
including important modifications to improve its predicting power. For
instance, we add a more realistic wind model and provide a
self-consistent set of parameters independently validated. As an
example, we are able to simulate realistic barchan dunes, which are the
basic solution of the model in the condition of unidirectional flow and
scarce sediments. From the simulation, we extract new relations
describing the morphology and dynamics of barchans that compare very
well with existing field data. Next, we revisit the problem of the
stability of barchan dunes and argue that they are intrinsically
unstable bed-forms. Finally, we perform more complex simulations: first,
a barchan dune under variable wind strength and, second, barchan dune
fields under different boundary conditions. The latter has important
implications for the problem of the genesis of barchan dunes. Copyright
(C) 2010 John Wiley & Sons, Ltd.
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