Author(s): Philippe Frey; Remi Chassagne; Raphal Maurin; Julien Chauchat

Linked Author(s): Philippe Frey

Keywords: No Keywords

Abstract: In order to study vertical grain size sorting in bedload sediment transport, numerical experiments of two-size particle mixtures were carried out, using a validated coupled fluid-discrete element model developed at Irstea. A 3D 10% steep domain, consisting at initial time of a given number of layers of 4 mm particles deposited on top of a coarser 6 mm particle bed, was sheared by a turbulent and supercritical fluid flow (Shields numbers of 0.1 and 0.3). The elevation of the centre of mass of the infiltrated fine particles is observed to follow the same logarithmic decrease with time, whatever the initial number of fine layers. This decrease is steeper for a higher Shields number. The main result is that this typical behaviour is related at first order to the particle shear rate depth profile.

DOI: https://doi.org/10.1051/e3sconf/20184004013

Year: 2018