Relaxation dynamics of vibrated dense granular media: Hysteresis and nonlocal effects

Understanding the relaxation process of driven dense granular materials is crucial to the avalanche dynamics and earthquake triggering in geophysics. However, quantitative description or prediction of vibrated dense flows remains largely unexplored. Motivated by theoretical models developed for the glass transition, we quantita-tively describe the vibration dependency of dynamical heterogeneities in a vibrated inclined flow exhibiting large hysteresis of the avalanche angle. We reveal that increasing vibration intensity weakens the nonlocal effects and susceptibility which are two crucial factors to triggering hysteresis. Combined with the effect of vibration amplitude on the nonlocal effects and the introduction of nonmonotonicity quantified by the peaks of suscep-tibility, the nonlocal granular fluidity (NGF) model quantitatively reproduces the key features of the hysteresis observed in the numerical simulations and previous experiments. Our work can readily be extended to arbitrary geometries and paves a route toward modeling other complex phenomena in dense granular flow.

Automated summary

Understanding the relaxation process of driven dense granular materials is crucial to the avalanche dynamics and earthquake triggering in geophysics. However, quantitative description or prediction of vibrated dense flows remains largely unexplored. In this study, we quantitatively describe the vibration dependency of dynamical heterogeneities in a vibrated inclined flow exhibiting large hysteresis of the avalanche angle, motivated by theoretical models developed for the glass transition.