Verification of filtered Two-Fluid Models in different flow regimes

This paper compares coarse grid simulations completed with various filtered models to computationally very expensive resolved simulations of fluidization in a 2D setup. It was shown that the original one-marker filtered model performed best. Surprisingly, more recently presented two-marker models showed substantial deviations from the resolved simulations. Unfortunately, one-marker models are not suitable for general large-scale fluidized bed simulations. Therefore, the performance of a new two-marker model is assessed, which respects certain limits when correcting the drag force and uses a normalized filtered slip velocity. While the initial results with this new model are encouraging, substantial uncertainty still exists due to the present lack of a dedicated filtered stress model.