A new set of scaling relationships for DEM-CFD simulations of fluid–solid coupling problems in saturated and cohesiveless granular soils

The discrete element method (DEM) cannot effectively account for macroscale problems because of its high computational cost and time-consuming nature, especially for fluid–solid coupling problems. Therefore, a spatially scaled-down model, which should be established based on a set of scaling laws, is commonly employed to study the behaviors of the macroscale prototype. In the present study, various basic scaling relationships proposed by previous researchers for a scaled-down model are summarized first, as well as their limitations when they are used for DEM-CFD simulation of fluid–solid coupling problems in saturated and cohesiveless granular soils. Then, a new set of scaling relationships is proposed using a governing equation approach. Finally, a DEM-CFD model is established as an example analysis to study the feasibility and accuracy of the new scaling relationship present in this study for simulating fluid–solid coupling problems in saturated and cohesiveless granular soils. The results are analyzed in comparison with other scaling relationships, and the results indicate that the new set of scaling relationships is more reasonable and accurate than others.