Rheological behavior of dense granular suspensions of cohesive particles

Intense sediment transport situations such as debris flows and mudslides consisting of fine-grained particles can pose serious threats to human infrastructures and lives. A thorough understanding of the rheology of such cohesive granular flows is crucial to predict the behavior of these types of flow and to mitigate their damaging effects. Whereas the rheology of non-cohesive granular flows has been studied extensively in the literature, the effect of cohesive inter-particle forces on the rheological behavior is still obscure and has not been sufficiently addressed. In this study, employing particle-resolved Direct Numerical Simulations, we simulate non-cohesive and cohesive dense suspensions sheared by moving walls. We perform several high-resolution simulations and compare the rheological parameters of the suspensions for different values of a dimensionless cohesive number, Co. Direct Numerical Simulations enable us to delve into the stress profiles in the vertical and streamwise directions and explore the contribution of different particle and fluid stresses to the total stress in each direction. We will also investigate the microstructure of the suspension and relate the microscopic interactions to macromechanical, rheological behavior of the dense cohesive suspension.