Investigating the effect of mixing layer rheology on granular flow over entrainable beds using SPH method

Abstract

This paper numerically studies the interaction of a flowing granular material with an entrainable granular bed, while materials are mixed at the interface of two materials. The rheological behavior of this granular mixture is characterized by a generalized viscoplastic model that includes local volume fraction of materials as well as their physical properties, i.e. size, density, and friction angle. Additionally, the effect of the dynamics of entrained bed-type particles on the rheology of the granular mixture is considered. The governing equations of the flow are discretized using the Incompressible Smoothed Particle Hydrodynamics (SPH) method in which mixing of particles can be conveniently simulated. Two benchmark problems, with and without entrainment, are solved to assess the accuracy of the underlying computational procedure in the absence of mixing. Some other test cases are also solved by including the mixing effect, and the effect of various model parameters is studied. Variations in momentum, maximum velocity, and total kinetic energy of flow with time are reported, and some physical interpretations are presented.