Extensive experimental results on the free fall of a range of non-spherical particles such as square bars, cylinders, spheres and crushed rock chips in Newtonian, inelastic, viscoelastic and Boger fluids are presented. It is demonstrated that the use of a volume equivalent sphere diameter in addition to a shape factor provides an adequate approximation for the non-sphericity of particles used in this study. The applicability of two rheological models, namely, the power-law and the Carreau viscosity model has been examined in representing the drag coefficient results. Appropriate predictive expressions of the drag coefficient as a function of the particle Reynolds number and the Deborah number, encompassing wide ranges of rheological and kinematic conditions, are presented.
On presente une grande quantite de resultats experimentaux sur la chute libre de particules non spheriques telles que des barres, des cylindres, des spheres et des debris de pierre dans des fluides de Boger, newtoniens, non elastiques et viscoelastiques. On demontre que le fait d'utiliser un diametre de sphere equivalent au volume en plus d'un facteur de forme donne une approximation convenable de la non-sphericite des particules utilisees dans cette etude. L'applicabilite de deux modeles rheologiques, soit le modele de loi de puissance et le modele de Carreau, a ete examinee pour la representation des resultats de coefficient de trainee. On presente des expressions de prediction adequates pour le coefficient de trainee en fonction du nombre de Reynolds et du nombre de Deborah des particules, et ce pour une vaste gamme de conditions rheologiques et cinematiques.
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