ABSTRACT
Numerical simulations of the unidirectional flow over dunes, coupled with bed and suspended sediment transport, are presented. The simulations are based on the numerical solution of the Navier-Stokes equations and the advection-diffusion equation for the suspended load, while empirical formulas are used for the bed load. The Immersed Boundary method is implemented for the imposition of fluid and sediment boundary conditions on the dune surface. We examined cases of three identical, consecutive dunes, and results are presented for cases of dune length to channel depth ratios of 3,5 and 7 , and dune height to channel depth ratios of 0.15,0.25 and 0.35, at Reynolds number equal to https://www.w3.org/1998/Math/MathML"> 5 × 10 3 https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429069246/b59e18fc-9e1d-4389-b000-a1069c1cd27e/content/eq7216.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> and Froude number equal to 0.2. The bed load distribution along the dunes and the evolution of suspended sediment is correlated to the vortical structures, which are generated at the dune crest due to flow separation.
