Volume of fluid-discrete element method based the simulation of floating object motion characteristics in complex terrain.

This article focuses on the development and validation of a multi-sphere volume of fluid-discrete element method (VOF-DEM) solver, which couples open-source codes (OpenFOAM, LIGGGHTS, and CFDEM) to simulate the motion of floating objects on free liquid surfaces within complex terrain channels. The solver addresses challenges in computational fluid dynamics (CFD) related to dynamic meshing and immersed boundary methods by employing an unresolved CFD-DEM coupling with drag force corrections tailored for multi-spherical particle models, enabling accurate simulation of non-spherical objects such as blocks and ship hulls. Validation against experimental data—including single particle sedimentation, cubic block settling, and floating wood blocks—demonstrated errors below 7.22%, confirming the solver's accuracy across a range of Reynolds numbers. The solver's application to large-scale river terrain with polyhedral meshes illustrated its capability to predict the dynamic behavior of drifting boats near bridge piers, highlighting its potential for engineering design and water conservancy projects by improving computational efficiency and handling complex 3D terrain fluid-solid interactions.