Author(s): Seline Frei; Benjamin Hohermuth; Davide Vanzo; David F. Vetsch

Linked Author(s): David Vetsch, Davide Vanzo

Keywords: Rmour layer; Bedload transport; Grain size class; Numerical simulation

Abstract: The discretization of the grain-size distribution into multiple grain-size classes, needed to setup morphodynamic numerical models, affects selective transport and hence the ability of the bed to develop an armour layer. Currently, there are no conclusive guidelines on how to discretize the grain-size distribution for mixed-sized sediment simulations. Therefore, we reproduced the degradation experiment of Gunter with a 1D numerical model and tested a different number of grain-size classes for two grain-size distributions with different distribution width. Further, the numerical model was validated against the experimental data. The degradation experiment proved to be a meaningful setup to test the sensitivity of different discretizations of the grain-size distribution. Our results show that the adequate number of grain-size classes to be used depends on the width of the grain-size distribution and ranged from 2 to 5 in our tests.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p0418-cd

Year: 2023