Particulate flows are very important in engineering and sciences while modeling particulate flows is usually a big challenge as the interaction of fluids and particles need to be well simulated.  The fully resolved CFD-DEM is accurate but costly as it directly calculates force between fluids and particles through resolving the boundary of each particle with very fine mesh grid.  In contrast, the unresolved CFD-DEM is efficient as it calculates the force between fluids and particles using certain empirical force model which requires coarse mesh.

In this work, through domain expansion and kernel-based approximation, we developed a semi-resolved CFD-DEM approach which leverage the advantages of the fully resolved CFD-DEM and unresolved CFD-DEM in terms of accuracy and efficiency. A number of numerical simulations including the sedimentation of single particle, separation of particles in a fluidized bed, spouted bed with heat particles, particulate flows in complex porous media, additive manufacturing (selective laser melting and direct laser deposition) have been conducted. It is shown that the presented semi-resolved CFD-DEM bridges the simulation gap between the resolved CFD-DEM and unresolved CFD-DEM while it is as efficient as the conventional unresolved CFD-DEM and as accurate as the resolved CFD-DEM.