Drag, lift, and moment coefficients for non-spherical particles in bounded and unbounded Flows at low to moderate Reynolds number*

Accurate predictions of hydrodynamic forces acting on a spherical and non-spherical particle are of fundamental importance in predicting the particle traveling velocity in a given flow. Traditionally, in simulations conducted for complex industrial particle-laden flows, a spherical particle shape is often assumed to simplify calculations even if particles are not spherically shaped. Spherical particles placed in bounded and unbounded flow have been extensively studied in the literature, while far fewer studies have examined the effect of the wall on predicting the coefficients of drag, lift, and moment for non-spherical particles; this is addressed in the present work using direct numerical simulations. Comparisons to data for spherical particles are carried out over a wide range of Reynolds numbers, particle-wall distance, and particle aspect ratio. The results suggest that spherical and non-spherical particles near the wall in shear bounded flow tend to have higher drag and moments than those away from the wall and those in unbounded flow conditions. Furthermore, the particles experience transverse lift affected by the presence of the wall driving them either away or closer to the wall. We also outline how these results can lead to the development of correlations for drag, lift, and moment coefficients for non-spherical particles which can be embedded in numerical codes for increased computational accuracy and efficiency.