Rheology of suspensions of non-Brownian soft spheres across the jamming and viscous-to-inertial transitions
The rheology of suspensions of non-Brownian, soft, and frictionless spheres is studied across jamming but also across the viscous and inertial regimes using a custom pressure- and volume-imposed rheometer. Using pressure-imposed rheometry, we show that the usual granular rheology found for suspensions of hard spheres can be generalized to a soft granular rheology by renormalizing the critical volume fraction and friction coefficient to pressure-dependent values and using the addition of stress scales. Using volume-imposed rheometry, we find same critical rheological behavior around jamming across flow regimes with same power laws of the distance to jamming as those found for soft colloids when using again stress additivity. These results support the conclusion that suspensions of soft particles across flow regimes can be described by a common framework around the jamming transition.