Hydrodynamic force on a hemispheroidal particle attached to a planar surface in linear shear flow

Abstract

This paper presents a computational fluid dynamics (CFD) study of the hydrodynamic force exerted on a prolate hemispheroidal particle (as a model geometry for debris formed during glass cutting) attached to a planar solid surface under linear shear flow. The three-dimensional conservation equations for mass and momentum are solved using a finite-volume scheme on a polyhedral mesh to compute the steady flow field around the particle and determine the hydrodynamic force on the particle as a function of particle aspect ratio (ε), pitch angle (θp) with respect to the surface, and orientation angle (θf) with respect to the flow direction. The computational results are used to develop a correlation for the drag coefficient (CD) in terms of more general shape descriptors that can be used for particles of irregular shape (i.e., with no symmetry)– namely, lateral view factor (ψl), particle separation (ψs), and dimensionless hydraulic radius (ψh). Computations are also performed for several particles with irregular shapes (resembling glass debris) and the CFD results for drag coefficient are compared to predictions of the empirical correlation. The drag coefficient correlation resulting from this study will be useful for estimating the hydrodynamic drag force exerted by the flow of cleaning fluids on irregularly-shaped particles adhering to planar solid surfaces.