2016/02/29 by Raphaël Maurin, Raphael Maurin, Julien Chauchat +1
Engineering · Environmental Science · Mathematics · Physics and Astronomy · #Bed load #Cauchy stress tensor #Classical mechanics #Flow (mathematics) #Geology #Geometry #Geomorphology #Geotechnical engineering #Granular flow and fluidized beds #Granular material #Landslides and related hazards #Mathematics #Mechanics #Particle Dynamics in Fluid Flows #Physics #Rheology #Scaling #Sediment #Sediment transport #Shear stress #Thermodynamics #Turbulence #cond-mat.mtrl-sci #physics.geo-ph
paper · pdf · doi:10.1017/jfm.2016.520
published as Journal of Fluid Mechanics, 804, pp. 490-512 (2016)
openalex publication_date 2016/09/09 · arxiv created 2016/11/05 · arxiv updated 2016/11/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The local granular rheology is investigated numerically in turbulent bedload transport. Considering spherical particles, steady uniform configurations are simulated using a coupled fluid–discrete-element model. The stress tensor is computed as a function of the depth for a series of simulations varying the Shields number, the specific density and the particle diameter. The results are analysed in the framework of the \unicode[STIX]x1D707(I) rheology and exhibit a collapse of both the shear to normal stress ratio and the solid volume fraction over a wide range of inertial numbers. Contrary to expectations, the effect of the interstitial fluid on the granular rheology is shown to be negligible, supporting recent work suggesting the absence of a clear transition between the free-fall and turbulent regimes. In addition, data collapse is observed up to unexpectedly high inertial numbers I∼ 2 , challenging the existing conceptions and parametrisation of the \unicode[STIX]x1D707(I) rheology. Focusing upon bedload transport modelling, the results are pragmatically analysed in the \unicode[STIX]x1D707(I) framework in order to propose a granular rheology for bedload transport. The proposed rheology is tested using a 1D volume-averaged two-phase continuous model, and is shown to accurately reproduce the dense granular flow profiles and the sediment transport rate over a wide range of Shields numbers. The present contribution represents a step in the upscaling process from particle-scale simulations towards large-scale applications involving complex flow geometry.