Modeling free-surface flows of granular column collapses using a mesh-free method

•A robust MPS model to simulate granular flows is developed.•A constitutive law to describe granular flows is validated by MPS model.•Glass bead and sand flows are extensively modeled, and surface profiles and front wave movements are simulated well.•The surface flowing and quasi-static internal structure in granular flows are clearly produced•The simulation results show that initial column ratio plays a significant role in granular spreading.

The dry granular mass in the dense flow regime can be considered as continuum and incompressible and is modeled in this study by using a mesh-free method, moving particle semi-implicit method (MPS). A local rheology model is employed to calculate the effective viscosity and shear stress in granular flows in the numerical method. Flows of cylindrical column collapse on planes and rectangular dam-break in channels containing glass beads and sands were respectively simulated in two-dimensional. From modeling a series of granular flows, the rheology model in MPS reproduced the flow characteristics of granular materials including flowing surface and the distinct static internal part where low velocity exists. The simulations prove that the initial column ratio played an important role in the spreading of granular mass. The surface profiles and wave front movements were compared with experimental data from literatures. After a transient period in the initial flow, the wave front of the granular flow approximately travels in a constant speed which was similar to that observed in the experiments. The final wave front in the simulations also showed good agreement with the relationship obtained from experiments.

Graphical abstractSimulation snapshots of glass bead dam-breaking flow with column aspect ratio h0/l0 = 7.0.Figure optionsDownload full-size imageDownload as PowerPoint slide