Author(s): L. Umach; R. Klar; S. Achleitner; M. Aufleger
Linked Author(s): Lukas Umach
Keywords: 2D-numerical modelling; Fractional bed load transport; Optimum discretisation
Abstract: For the reduction of computational efforts in bed load simulations, the number of fractions to approximate the natural grading curve needs to be limited. This work focuses on the sensitivity of simulated spatial distributions of morphological changes with regard to a varying number of grain classes. It is vital to balance the refinement of fractions against the gained improvement in simulation results. In general there is a link expected to the grain size distribution and the river topography. The sensitivity analysis was made based on various scenarios, working towards a guidance to use the mandatory discretisation of fractions. For the simulation of each scenario a two-dimensional numerical software including a multi fraction-multi layer approach for bed load transport was applied to a straight river reach. Characteristic values such as mean diameter, slope or specific discharge may provide a stable link to the optimum number of fractions needed.
Year: 2011