Microscale insights into shear viscosity scaling of granular suspensions across the jamming transition

We present evidence of the jamming transition across semi-dilute to dense regimes in suspensions from a thorough study combining both experiments and numerical results. Following an extensive experimental study, where such a transition was observed, we perform constant-volume shearing simulations of non-Brownian granular suspensions using the discrete element method coupled with the lattice Boltzmann method. We choose a wide range of solid fractions, shear rates, fluid viscosities, particle sizes, particle stiffness, and inter-particle frictional coefficients to obtain a scaling solution for the viscous behavior of suspensions in both semi-dilute and dense regimes. This result demonstrates that, with the semi-dilute-dense jamming transitional solid fraction, ϕd, there exists a strong correlation between the inverse relative viscosity and the shear stress. The transitional behavior of suspensions closely corresponds to the microstructure development, especially the largest particle cluster. Suspensions undergo a jamming transition when the contact network across the whole system is formed. This work incorporates both the ϕ-dependence and the γ̇-dependence of suspension viscosity in a universal framework, which provides a scaling solution for granular suspensions across semi-dilute and dense regimes and sheds light on the jamming transition mechanisms.