Modeling of debris flows and induced phenomena with non-Newtonian fluid models

Debris flows contain inhomogeneous distributions of solids within a liquid. By considering a mixture of solid and liquid forming debris flows as a non-Newtonian continuous liquid, the viscosity term for rheological models is simply constructed in the Navier-Stokes equations. Time-independent models (e.g. Herschel-Bulkely) for viscosity have been widely used, but there is an open question as to whether time-dependent models might provide improved results. In this work, both time-dependent and time-independent non-Newtonian fluid models are taken into account in simulation. Since debris flow induced phenomena include two or more interfaces, the level set method for multiple materials is applied as the interface tracking method. The numerical model is applied to two-dimensional test cases to validate this approach and analyze the relative importance of the viscosity model. The simulation results for the two models show reasonable agreement with available experimental data in most cases, however, time-dependent model only shows good correlation with experimental measurements for special case. It indicates that debris flows and induced phenomena could be simulated by the approach of this research and the time-dependent model is more adequate for representing real debris flows than time-independent models.Civil, Architectural, and Environmental Engineerin