Debris Flows: Recent Advances in Experiments and Modeling

Abstract

Abstract We report on recent advances in experiments and modeling of particle–fluid flows that are relevant to an understanding of debris flows. We first describe laboratory experiments on steady, inclined flows of mixtures of water and a single idealized granular phase that focus on the differences in the depths and the velocity of the two phases and that provide evidence for the importance of collisional exchange of momentum and energy between the particles. We then indicate how a relatively simple rate-dependent rheological model for the particles that incorporates yield may be used in the context of a two-phase mixture theory that distinguishes between the depths of the fluid and particle phases to reproduce what is seen in the experiments on both uniform and non-uniform flows. Finally, because a phenomenological extension of kinetic theory for dense, inclined flows of identical particles has recently been developed, we outline a kinetic theory for dense, inclined flows of two types of particles and water as a possible alternative to existing phenomenological theories.