Cross-stream diffusion in bedload transport - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Physics of Fluids Année : 2014

Cross-stream diffusion in bedload transport

Résumé

We investigate experimentally the statistical properties of bedload transport induced by a steady, uniform, and laminar flow. We focus chiefly on lateral transport. The analysis is restricted to experiments where the flow-induced shear stress is just above the threshold for sediment transport. We find that, in this regime, the concentration of moving particles is low enough to neglect interactions between themselves. We can therefore represent bedload as a thin layer of independent walkers travelling over the bed surface. In addition to their downstream motion, the particles show significant fluctuations of their cross-stream velocity, likely due to the roughness of the underlying sediment bed. This causes particles to disperse laterally. Based on thousands of individual trajectories, we show that this lateral spreading is the manifestation of a random walk. The experiments are entirely consistent with Fickian diffusion.
Fichier principal
Vignette du fichier
DiffusionSub2-2.pdf (1.67 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

hal-01500382 , version 1 (12-04-2017)

Identifiants

Citer

Grégoire Seizilles, Eric Lajeunesse, Olivier Devauchelle, Michael Bak. Cross-stream diffusion in bedload transport. Physics of Fluids, 2014, 26 (1), pp.013302. ⟨10.1063/1.4861001⟩. ⟨hal-01500382⟩
44 Consultations
277 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More