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 * = σ 22 a 2 / F 0 , compares the applied normal stress σ 22 on grains of diameter a to the tensile strength of contact F 0 (proportional to the surface tension Г 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 under controlled normal stress σ 22 . 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.