Fig. 3: Particle flow profiles from micro-rheology experiment and simulation.

A The flow profiles from experiment in the smallest funnel (\(\bar{D}\) = 12, D = 0.75 mm) adopts a parabolic shape which proceeds to flatten out with increasing funnel size into the characteristic plug style profile expected of a flowing granular material at the largest size (\(\bar{D}\) = 32, D = 1.75 mm). Shading represents a standard deviation calculated across 5 independent funnel flips. B Particle flow profiles from DEM simulation. Here, a cohesive interparticle force of ϕ = 0.001 Nm⁻¹ is added to the force equation. Only for ϕ = 0.001 Nm⁻¹, shown here, do we observe the parabolic to plug flow profile transition: if ϕ is too small, plug flow is observed regardless of funnel size; if ϕ is too large, the funnel clogs. Shading represents a standard deviation calculated across 16 independent simulations.