Fluid-particle drag force measurements from particle-resolved CFD simulations of flow past random arrays of ellipsoidal particles

Abstract The lack of constitutive drag laws for non-spherical particles represents a current gap in simulating fluid-particle flows, even though such non-spherical shapes are encountered in numerous applications. Some previous studies have applied spherical drag models to non-spherical particles, while others have used ad-hoc methods to account for particle shapes. However, the present work demonstrates the need to develop dedicated non-spherical drag laws, given the limitations of these previous ad-hoc approaches. In the present study, single-phase computational fluid dynamics (CFD) simulations of fluid flow over random arrays of ellipsoids are used to directly calculate the fluid-particle drag forces. By varying the particle shape, orientation, solid fraction, and fluid-flow velocity (Reynolds number), this work probes the variables that would be important for future model development. A preliminary non-spherical drag model is proposed based on the CFD results, which illustrates the functional dependency of the non-spherical drag on particle aspect ratio and orientation.