Author(s): M. Nabi
Linked Author(s):
Keywords: River morphology; Sediment transport; Large Eddy Simulation; Particles; Immersed boundaries; Cartesian grid
Abstract: We are developing a numerical model for simulating the development and migration of dunes in rivers in 3D case. The numerical model consists of three modules: turbulent flow, sediment transport and morphology. We present these steps in which we modelled turbulent flow using state-of-the-art techniques for detailed hydrodynamics. The sediment is considered as suspended particles in the turbulent flow. The morphology is simulated using empirical relations for pickup and deposition of sediment from the bed. A finite volume method combined with an isotropic unstructured Cartesian grid with local refining is developed for simulating time-dependent incompressible flow. The grid can be refined and can adapt to the boundaries. The governing equations are discretized using a staggered grid and advance in time using the fractional step method. The Cartesian grid cells and faces are managed using an unstructured data approach. A ghost-cell immersed-boundary technique has been implemented for the cells which intersect the immersed boundaries. Because of the importance of coherent structures of turbulence on sediment transport, the turbulence regime is modelled by Large Eddy Simulation.
Year: 2010