Novel Sphericity-Dependent Drag Model for Accelerated Motion of Non-Spherical Particles in Viscous Medium

Abstract

A novel sphericity-dependent drag model for the accelerated motion of non-spherical particles in Newtonian fluids has been developed. The main advantage of the model is that it has a simple Reynolds number dependence that is suitable for analytical solutions of accelerated particle motion. The present model was developed using nonlinear regression analysis of simulated data obtained from a published model with complex Reynolds number dependence. The present model was validated with published experimental data having sphericities of 0.471 – 1.00 and valid for Reynolds number of 0.01 – 10000. An error analysis of the present model and other published sphericity-dependent models showed that the present model had the lowest root-mean-square error. Therefore, the present drag model was applied to derive closed-form solutions for the accelerated motion of a non-spherical particle and a new settling velocity formula. The closed-form solutions were used to investigate the effect of sphericity on the accelerated motion for non-zero initial velocity.