Jamming, Yielding, and Rheology during Submerged Granular Avalanche

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, GY and G₀, categorize the material's state into solid-like, creeping, and fluid-like states. Yielding at GY marks the transition from solid-like to creeping, while G₀ signifies the shift to the fluid-like state. The μ-G relationship converges towards the equilibrium μeq(G) after G>G₀ showing the critical point where the established rheological laws for steady states apply during transient conditions.