Jamming, Yielding, and Rheology during Submerged Granular Avalanche

TL;DR

This study combines experiments and simulations to analyze jamming, yielding, and rheology in submerged granular avalanches, introducing a new length-scale ratio G to unify pressure and shear rate effects.

Contribution

It introduces the length-scale ratio G as a unified metric for granular rheology and identifies key transition points G_Y and G_0 for different material states.

Findings

Simulation and experimental results match closely, validating the simulation method.

G effectively captures the transition from solid-like to fluid-like states.

The μ-G relationship converges to equilibrium after G exceeds G_0.

Abstract

Jamming transitions and the rheology of granular avalanches in fluids are investigated using experiments and numerical simulations. Simulations use the lattice-Boltzmann method coupled with the discrete element method, providing detailed stress and deformation data. Both simulations and experiments present a perfect match with each other in carefully conducted deposition experiments, validating the simulation method. We analyze transient rheological laws and jamming transitions using our recently introduced length-scale ratio $G$. $G$ serves as a unified metric for the pressure and shear rate capturing the dynamics of sheared fluid-granular systems. Two key transition points, $G_{Y}$ and $G_{0}$, categorize the material's state into solid-like, creeping, and fluid-like states. Yielding at $G_{Y}$ marks the transition from solid-like to creeping, while $G_{0}$ signifies the shift to the fluid-like state. The $\mu-G$ relationship converges towards the equilibrium $\mu_{eq}(G)$ after $G>G_0$ showing the critical point where the established rheological laws for steady states apply during transient conditions.