Controlling Rheology via Boundary Conditions in Dense Granular Flows

EXECUTIVE SUMMARY

2 conditions for the first time, and address the main Aims.

Rheology (I). This will allow us to separately determine constitutive parameters and boundary data of the type collected here, we will soon be fully able to calculate the fluidity g(r) and the elucidate the nontrivial connection between these observations, which so far is confounding. Using techniques, are similarly affected by the roughness and compliance of the wall. Future work will of the flow, allowing us to observe that the pressure P and shear stress, measured by photoelastic of the flow most sensitive to nonlocal effects. Photoelastic techniques provide us full stress profile v(r) and shear rate profile _ (r), particularly as measured at the outer wall. This is also the region boundaries. We have observed that boundary roughness strongly controls both the flow profile both particle-dynamics and stress fields under controlled conditions for six different-roughness.

As Year 5 comes to a close, we have used fully-developed experimental protocols to measure properties.

On separating which flow properties are set by the particle properties, versus those set by the wall and (2) use these parameters to predict flows in other geometries. Thus, our current work focuses can we (1) make flow measurements in one geometry which determine the constitutive parameters and apply NLR to real granular systems. We aim to establish that, for a given set of particles, in Years 4-6 of this project, we aim to address current shortcomings in how to calibrate (A; b; s), but that we must know the amount of slip at the wall from geometry-dependent measurements.

Packing densities, particle sizes and shapes, and shear rates, using just 3 constitutive properties. In Years 1-3, we established that NLR successfully models granular flows across different both the particle properties, and the boundary conditions at the walls. The same particles). Doing this requires a quantitative understanding of which properties are set by and then determine the constitutive parameters for use in predicting flows in other geometries (for to be useful, the aim is to make a set of flow measurements for a set of particles in one geometry, large range of intermittent, creeping, quasi-static, and intermediate flows. In order for these models for a particular set of particles, which then can be used to predict flow fields and stresses over a models hold the promise of permitting the determination of a small number of empirical parameters been the development of various nonlocal rheologies [2, 4, 5, 11, 13, 15, 25]. These constitutive.

In the field of granular rheology, one of the most promising advances of the past decade has.