Rheology of wet granular materials under continuous shear: Experiments and simulations

The behaviour of wet granular media in shear flow is characterized by the dependence of apparent friction μ∗ and solid fraction Φ_s on the reduced pressure P∗ and the inertia number I. Reduced pressure, P∗ = σ₂₂a²/F₀, compares the applied normal stress σ₂₂ on grains of diameter a to the tensile strength of contact F₀ (proportional to the surface tension Cyrillic capital letter GHE of the liquid and the beads diameter). A specifically modified rotational rheometer is used to characterize the response of model wet granular material to applied shear rate $\dot \gamma $ under controlled normal stress σ₂₂. Discrete Element Method (DEM) simulations in 3D are carried out in parallel and numerical results are compared with experimental ones. Cohesive, inertia, saturation and viscous effects on macroscopic coefficient of friction μ∗ and solid fraction Φ_s are discussed.