A Semi‐Resolved VOF‐DEM Coupling Method for Bedload Transport of Non‐Spherical Particles

Abstract

Bedload transport of coarse sediments involves complex particle‐flow interactions that govern sediment motion and bed surface evolution. In this study, a semi‐resolved CFD‐DEM method is developed to simulate bedload sediment dynamics, in which the background fluid information for each particle is calculated using a Gaussian kernel function. Both particle shape effects and free‐surface dynamics are explicitly considered. A bonded‐sphere model is employed to construct disk‐like non‐spherical particles, and a series of validation cases are performed to assess the reliability of the proposed method. Comparisons between spherical and non‐spherical particles are conducted under different flow conditions, including single‐particle settling, two‐particle interaction during settling, and bedload transport simulations. In addition, the proposed method enables the simulation of the evolution of bed surface self‐organization, including particle clustering patterns and imbricated structures. The results indicate that accounting for particle‐scale flow disturbances is essential for accurately reproducing bed surface self‐organized structures, which cannot be captured by conventional unresolved CFD‐DEM method.