Analysis of the rheological behavior of suspensions by using the Immersed Boundary Method (IBM) coupled with the Discrete Element Method (DEM)

We implemented fully resolved CFD-DEM simulations to study the rheological behavior of suspensions. Although research in this field mainly uses 2D or 3D simulations to achieve this purpose, we proposed a semi-3D model. By semi-3D models, we mean that the simulation domain contains only one layer of particles in the 3D case. Comparing results with 3D simulations revealed that this approach could significantly decrease the simulation cost while maintaining reasonable accuracy. Furthermore, we selected the Krieger-Dougherty and the Phillips models to validate the viscosity and particle migration in our simulations. We considered different volume fractions of solid particles with two different particle sizes to ensure the accuracy of our model. After successful validation, we used the fully resolved field data of shear rate and vorticity to consider the physics of particular migration in more detail. Our results confirm that our developed model could work as a particle-fluid digital twin system.