Author(s): G. Rosatti; L. Begnudelli
Linked Author(s): Giorgio Rosatti
Keywords: No Keywords
Abstract: Debris-flows in anthropized fans often encounter sections where the bed is inerodible or presents fixed bed-step, like open or closed check dams, walls and so on. Numerical simulations of Debris-flows are often performed using finitevolume, Godunov numerical schemes which require the solution, either exact or approximated, of a Riemann Problem at the cell interfaces. This paper is addressed to the solution of a Riemann Problem that a hyperconcentrated 1D freesurface shallow flow develops in presence of a discontinuity of the bed (Step Riemann Problem, SRP). This topic is firstly faced from a theoretical point of view. The peculiar features of the SRP are presented as well as the open problems that still affect this subject. Then we present a numerical strategy based on a novel two-step predictorcorrector algorithm: in the predictor step, a well-balanced Roe solver is used in order to provide an estimation of the wave structure arising from the cell-interface, while in the corrector step the exact SRP is solved by means of an efficient iterative procedure. Finally, we analyze the capabilities of the proposed solver by comparing numerical solutions with exact solutions of several SRPs.
Year: 2010