Author(s): Donatella Termini; Gerardo Bonvissuto
Linked Author(s): Donatella Termini
Keywords: Dynamic equilibrium; Degradation; Bed armouring
Abstract: In order to simulate successful bed degradation process in alluvial channels it is necessary to take into account the non-uniformity of the grains and the evolution of bed armouring. The critical point is how to predict the change of grain size distribution during the degradation process and the final composition of the “armour” layer. In this paper a procedure to simulate the evolution of bed armouring and degradation process in a straight channel is proposed. The variation of the bed is evaluated in function of friction factor, that reflects not only the variation of the hydraulics characteristics of the flow, but also the variation of the grain size distribution curve of sediments on the bed and, thus, of median sediment diameter during the process. The variation of the dimensions of bed forms is also considered.