Large Force Fluctuations in a Flowing Granular Medium

Abstract

We report the characteristics of the temporal fluctuations in the local force delivered to the wall of a 2D hopper by a granular medium flowing through it. The forces are predominantly impulsive at all flow rates for which the flow does not permanently jam. The average impulse delivered to the wall is much larger than the momentum acquired by a single particle under gravity between collisions, reflecting the fact that momentum is transferred to the walls from the bulk of the flow by collisions. At values larger than the average impulse, the probability distribution of impulses is broad and decays exponentially on the scale of the average impulse, just as it does in static granular media. At small impulse values, the probability distribution evolves continuously with flow velocity but does not show a clear signature of the transition from purely collisional flow to intermittently jamming flows. However, the time interval between collisions tends to a power law distribution, $P(\tau )\sim {\tau }^{-3/2}$, thus showing a clear dynamical signature of the approach to jamming.

4 pages, 3 figures

Cited by in corpus (20)

• A statistical mechanics framework for static granular matter
• NMR Experiments on a Three-Dimensional Vibrofluidized Granular Medium
• Invited review: Clogging of granular materials in bottlenecks
• Modified Archimedes' principle predicts rising and sinking of intruders in sheared granular flows
• Equipartition of rotational and translational energy in a dense granular gas
• Temporally heterogeneous dynamics in granular flows
• Long Range Correlations in Granular Shear Flow I: Numerical Evidence
• Impulse distributions in dense granular flows: signatures of large-scale spatial structures
• Topological rearrangements and stress fluctuations in quasi-two-dimensional hopper flow of emulsions
• Rheology of Weakly Vibrated Granular Media
• Effective boundary conditions for dense granular flows
• Stress and large-scale spatial structures in dense, driven granular flows
• Erosion dynamics of a wet granular medium
• Basal force fluctuations and granular rheology: Linking macroscopic descriptions of granular flows to bed forces with implications for monitoring signals
• Decomposition of force fluctuations far from equilibrium
• Growing length scale in gravity-driven dense granular flow
• On velocity profiles, stresses and Bagnold scaling of sheared granular system in zero gravity
• Phase transition in peristaltic transport of frictionless granular particles
• Simulations of collision times in gravity driven granular flow
• Pressure dynamics in the bottleneck flow of self-propelled particles