Lagrangian multiphase modeling of sand discharge into still water

Discharge of sand into water can be modeled as the multiphase flow of a non-Newtonian and a Newtonian fluid by treating the granular material as a continuum. The numerical modeling of this article is on the basis of the latest generation of computational methods, the mesh-free Lagrangian (particle) methods. In these methods, the solution domain is discretized by a set of nodes or particles, possessing the field variables and moving in a Lagrangian coordinates. This makes these methods the powerful tool for handling any deformation or fragmentation in interfaces, which is a usual problem in multiphase granular flow (e.g., sand–water systems). The Moving Particle Semi-implicit method (MPS) is used in this study. A multiphase non-Newtonian MPS approach is developed and applied to the case of sand discharge into still water. The results are validated using experimental measurements and analytical solutions to evaluate the accuracy of the model. The effects of flow conditions and rheological properties on the behaviour of sand discharge into water are also investigated.