Numerical simulation of sand dune evolution in severe winds
We present a novel approach for numerical simulation of fluid flow and sediment transport past evolutionary landforms, with emphasis on sand dunes developing in extreme winds. Time-dependent curvilinear coordinates are employed to fully couple flow aloft with the developing landform. The conservation law that defines shape of the lower boundary depends on details of local surface stress, thereby favouring a large eddy simulation of the atmospheric boundary layer. The flux-form partial differential equation for the interface profile-via saltation and sand avalanches-is formulated as an advection-diffusion equation. The latter facilitates discrete integrations using nonoscillatory algorithms-consistent with the nonoscillatory forward-in-time solver, based on MPDATA transport methods, employed to Simulate the boundary layer flow aloft. Theoretical discussions are illustrated with numerical experiments that explore the interactive evolution of the dune/atmosphere system. Copyright (c) 2005 John Wiley & Sons, Ltd.
saltation modelling sand dunes sand avalanches boundary layer sand dune coupling