Mathematical and Numerical Modelling of Fully Coupled Mobile Bed Free Surface Flows

Code:
03/2011
Title:
Mathematical and Numerical Modelling of Fully Coupled Mobile Bed Free Surface Flows
Date:
Thursday 13th January 2011
Author(s):
Garegnani, G.; Rosatti, G.; Bonaventura, L.
Download link:
Abstract:
We analyze the most widely used formulations of sediment transport modelling in the framework of one dimensional channel flow, thereby assessing the impact of typical simplifying assumptions, such as low sediment concentration and decoupling of hydrodynamics and bed evolution. As a result, the importance of using a quasi two-phase formulation is highlighted. Starting from the a quasi two-phase model equations, under the hypothesis of quasi-steady free surface and mixture flows, we derive a simplified equation for the bed evolution, that is also valid in the large sediment concentration regime. The solution of such a simplified equation provides a useful benchmark for numerical methods aimed at computing approximate solutions of the quasi two-phase system. Finally,we propose and evaluate a highly efficient and accurate semi-implicit and semi-Lagrangian numerical method for quasi two-phase mobile bed system.
This report, or a modified version of it, has been also submitted to, or published on
Journal of Hydraulic Research, Vol. 51, pp. 380-391, 2013