Two-scale evolution during shear reversal in dense suspensions

Abstract

We use shear reversal simulations to explore the rheology of dense, non-Brownian suspensions, resolving lubrication forces between neighbouring particles and modelling particle surface contacts. The transient stress response to an abrupt reversal of the direction of shear shows rate-independent, nonmonotonic behaviour, capturing the salient features of the corresponding classical experiments. Based on analyses of the hydrodynamic and particle contact stresses and related contact networks, we demonstrate distinct responses at small and large strains, associated with contact breakage and structural re-orientation, respectively, emphasising the importance of particle contacts. Consequently, the hydrodynamic and contact stresses evolve over disparate strain scales and with opposite trends, resulting in nonmonotonic behaviour when combined. We further elucidate the roles of particle roughness and repulsion in determining the microstructure and hence the stress response at each scale.

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Cited by in corpus (8)

• Tunable Shear Thickening in Suspensions
• Rheology of dense granular suspensions under extensional flow
• Shear Reversal in Dense Suspensions: The Challenge to Fabric Evolution Models from Simulation Data
• Constitutive model for time-dependent flows of shear-thickening suspensions
• Constitutive model for shear-thickening suspensions: Predictions for steady shear with superposed transverse oscillations
• Rheology of dense suspensions under shear rotation
• Linking particle properties to paste extrusion flow characteristics using discrete element simulations
• Orientational arrest in dense suspensions of elliptical particles under oscillatory shear flows