Rheology of mobile sediment beds in laminar shear flow: effects of creep and polydispersity

Abstract

Classical scaling relationships for rheological quantities such as the $\mu (J)$-rheology have become increasingly popular for closures of two-phase flow modeling. However, these frameworks have been derived for monodisperse particles. We aim to extend these considerations to sediment transport modeling by using a more realistic sediment composition. We investigate the rheological behavior of sheared sediment beds composed of polydisperse spherical particles in a laminar Couette-type shear flow. The sediment beds consist of particles with a diameter size ratio of up to ten, which corresponds to grains ranging from fine to coarse sand. The data was generated using fully coupled, grain resolved direct numerical simulations using a combined lattice Boltzmann - discrete element method. These highly-resolved data yield detailed depth-resolved profiles of the relevant physical quantities that determine the rheology, i.e., the local shear rate of the fluid, particle volume fraction, total shear, and granular pressure. A comparison against experimental data shows excellent agreement for the monodisperse case. We improve upon the parameterization of the $\mu (J)$-rheology by expressing its empirically derived parameters as a function of the maximum particle volume fraction. Furthermore, we extend these considerations by exploring the creeping regime for viscous numbers much lower than used by previous studies to calibrate these correlations. Considering the low viscous numbers of our data, we found that the friction coefficient governing the quasi-static state in the creeping regime tends to a finite value for vanishing shear, which decreases the critical friction coefficient by a factor of three for all cases investigated.

References in corpus (22)

• Numerical Simulations of Particulate Suspensions via a Discretized Boltzmann Equation Part I. Theoretical Foundation
• Crucial role of side walls for granular surface flows: consequences for the rheology
• Transition from viscous to inertial regime in dense suspensions
• Galilean Invariant Fluid-Solid Interfacial Dynamics in Lattice Boltzmann Simulations
• A constitutive model for simple shear of dense frictional suspensions
• Collision model for fully-resolved simulations of flows laden with finite-size particles
• Non-local rheology in dense granular flows -- Revisiting the concept of fluidity
• River-bed armoring as a granular segregation phenomenon
• A collision model for grain-resolving simulations of flows over dense, mobile, polydisperse granular sediment beds
• waLBerla: A block-structured high-performance framework for multiphysics simulations
• Interface-resolved direct numerical simulation of the erosion of a sediment bed sheared by laminar channel flow
• Bidisperse and polydisperse suspension rheology at large solid fraction
• Shear thickening regimes of dense non-Brownian suspensions
• A discrete model for the apparent viscosity of polydisperse suspensions including maximum packing fraction
• Settling of cohesive sediment: particle-resolved simulations
• Dense granular flow rheology in turbulent bedload transport
• A comparative study of fluid-particle coupling methods for fully resolved lattice Boltzmann simulations
• Rheology of sediment transported by a laminar flow
• The influence of surface roughness on the rheology of immersed and dry frictional spheres
• Local Rheology Relation with Variable Yield Stress Ratio across Dry, Wet, Dense, and Dilute Granular Flows
• Rheology of mobile sediment beds sheared by viscous, pressure-driven flows
• Modelling the Microstructure and Stress in Dense Suspensions Under Inhomogeneous Flow

Cited by in corpus (2)

• Scalable Flow Simulations with the Lattice Boltzmann Method
• Particle resuspension from complex multilayer deposits by laminar flows: statistical analysis and modeling