Validation of a fluid-solid multiphase flow simulation by a SPH-DEM coupled method and soil foundation scour simulation with a coarse graining particle model

Disasters, such as sediment disaster caused by heavy rain and Tsunami disaster caused by an earthquake, are multiphase flow phenomena of fluid (water) and solid (soil). For damage prediction and countermeasure, fluid-solid analysis method is necessary since there is a scale limitation for an experiment. In this study, we develop multiphase simulator utilizing the Incompressible Smoothed Particle Hydrodynamics method (ISPH method) for fluid and Discrete Element Method (DEM) for solid. The interaction between ISPH method and DEM is implemented by considering an interaction force between fluid and solid. Free surface judgement is an important factor to obtain a good fluid analysis result. We utilize a method proposed by Marrone et al. to improve the free surface detection in a solid domain. In a simple validation test, dam break flow of water and glass beads, we validate and verify our method. At last, the method is applied to scouring analysis with a coarse graining particle model.