Author(s): Giuliani Matteo; Fraccarollo Luigi
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Keywords: Mobile bed; Shallow water; Riemann solvers; Sediment transport
Abstract: In this work a mathematical and numerical methodology to represent the morphological evolution of a river bed under strongly transient floods is presented. The mathematical model is borrowed from recent works devoted to massive sediment-laden flows, specialized to take full account of the mass and momentum exchanges between the instantaneous bed profile. The numerical approach is carefully keeping this point and may also cope with strong gradients in time and space of the solution and with the propagation of steep surges. It consists of a finite volume, explicit method of Godunov type, able to deal in an original, efficient and accurate way with the stiff task to evaluate differential terms expressing conservative and non-conservative fluxes and source terms. An innovative determination of the sediment fluxes in the frame of a lateralized HLL solver of Riemann problem is reported to produce fair results in comparison with some exact solutions. The skill of this approach to deal with any mobility of the grains transported and in the bed has been checked. A two dimensional application to a real case, with complex topography and demanding flow conditions has been yielded and here presented.
Year: 2007