Numerical simulation of the temporal evolution of a three dimensional barchanoid dune and the corresponding sediment dynamics

Abstract

In this paper we present the results of the numerical simulation of a three-dimensional current-driven sediment transport process. In detail, the temporal evolution of a barchanoid dune is studied. Two phenomena are treated in this context. First, the three-dimensional flow of a single phase fluid is considered. Second, the interaction of the flow and the sediment bed with its morphological change of the sediment surface is taken into account. Here, we numerically solve the instationary incompressible Navier-Stokes equations. The morphological change of the sediment bed is modelled by Exner’s bed level equation. Furthermore, the suspended material is treated as a sediment concentration and modelled by an advection-diffusion equation. Both models are discretised and explicitly coupled to the discrete fluid model. The typical sedimentary processes and the sedimentary form of a barchanoid dune are well captured by our numerical simulation.