This study presents a numerical method to investigate sediment transport processes from the micromechanical particulate perspective. This study applies a continuum-particulate modelling approach for the fluid-particle interaction, which couples computational fluid dynamics and discrete element method (CFD-DEM). This is implemented using the open-source OpenFOAM and LIGGGHTS packages. This model considers sediment beds as distinct particles where the particle-scale physical behaviour of the sediment movement is captured. This is coupled to a coarse-grained fluid domain that comprises multiple particles per fluid cell, which allows for computational efficiency in simulating the sediment transport process. The results from the simulations are examined and they agree well with well-established empirical results in the Shields diagram, showing promise of this modelling approach for understanding the details of sediment transport process in alluvial riverbeds.

Sediment transport,CFD-DEM; governing equations; coupling scheme; drag models