Interplay between hysteresis and nonlocality during onset and arrest of flow in granular materials.

  title={Interplay between hysteresis and nonlocality during onset and arrest of flow in granular materials.},
  author={Saviz Mowlavi and Ken Kamrin},
  journal={Soft matter},
The jamming transition in granular materials is well-known for exhibiting hysteresis, wherein the level of shear stress required to trigger flow is larger than that below which flow stops. Although such behavior is typically modeled as a simple non-monotonic flow rule, the rheology of granular materials is also nonlocal due to cooperativity at the grain scale, leading for instance to increased strengthening of the flow threshold as system size is reduced. We investigate how these two effects… 
3 Citations

Figures from this paper

Avalanches and deformation in glasses and disordered systems

In this chapter, we discuss avalanches in glasses and disordered systems, and the macroscopic dynamical behavior that they mediate. We briefly review three classes of systems where avalanches are

Modelling silo clogging with non-local granular rheology

Abstract Granular flow in a silo demonstrates multiple non-local rheological phenomena due to the finite size of grains. We solve the non-local granular fluidity continuum model in



Relaxation-type nonlocal inertial-number rheology for dry granular flows.

A constitutive model to describe the nonlocality, hysteresis, and several flow features of dry granular materials is proposed, and a dimensionless parameter reflecting the nonlocal effect on the flow is discovered, which controls the transition between Bagnold and creeping flow dynamics.

Size-dependence of the flow threshold in dense granular materials.

This paper considers three different examples of inhomogeneous flow using two-dimensional discrete-element method calculations and shows that the flow threshold is indeed size-dependent in these flow configurations, displaying additional strengthening as the system size is reduced.

Continuum modeling of secondary rheology in dense granular materials.

This work explores creep of a circular intruder in a two-dimensional annular Couette cell and shows that the model captures all salient features observed in experiments, including both the rate-independent nature of creep for sufficiently slow driving rates and the faster-than-linear increase in the creep speed with the force applied to the intruder.

Effect of particle surface friction on nonlocal constitutive behavior of flowing granular media

A recently proposed nonlocal rheology for dense granular flow, based on the concept of nonlocal granular fluidity, has demonstrated predictive capabilities in multiple geometries. This work is

Quasistatic to inertial transition in granular materials and the role of fluctuations.

It is shown that quasistatic zones are the seat of a creep process whose rate is directly related to the existence and magnitude of velocity fluctuations, and the origin of the transition between these two regimes is discussed.

A predictive, size-dependent continuum model for dense granular flows

A 3D constitutive model for well-developed, dense granular flows aimed at filling this need, with a grain-size-dependent nonlocal rheology—inspired by efforts for emulsions—in which flow at a point is affected by the local stress as well as the flow in neighboring material.

Rheology and structure of granular materials near the jamming transition

The shear stress of non-cohesive granular material in the vicinity of the jamming transition is supposed to be connected to the formation of transient rigid clusters of particles. The characteristics

Nonlocal modeling of granular flows down inclines.

The recently proposed nonlocal granular fluidity model is applied to this geometry and it is found that the model captures many of these effects, including the Froude number of the flows, which has been shown experimentally to collapse.

Spatial cooperativity in soft glassy flows

This work uses a microfluidic velocimetry technique to characterize the flow of thin layers of concentrated emulsions, confined in gaps of different thicknesses by surfaces of different roughnesses, and shows that a rather simple non-local flow rule can account for all the velocity profiles.

Nonlocal constitutive relation for steady granular flow.

A nonlocal fluidity relation for flowing granular materials is proposed, capturing several known finite-size effects observed in steady flow and comparing predicted velocity profiles against corresponding discrete element method simulations utilizing the same grain composition.