Influence of surface properties on the flow of a yield stress fluid around spheres

Autor: Albert Magnin, Fiacre Ahonguio, Laurent Jossic
Přispěvatelé: Laboratoire Rhéologie et Procédés (LRP), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Laboratoire de rhéologie (LR), Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Université Joseph Fourier - Grenoble 1 (UJF), Jossic, Laurent
Rok vydání: 2014
Předmět:
Zdroj: Journal of Non-Newtonian Fluid Mechanics
Journal of Non-Newtonian Fluid Mechanics, Elsevier, 2014, 206, pp.57-70
ISSN: 0377-0257
DOI: 10.1016/j.jnnfm.2014.03.002
Popis: This experimental analysis addresses the non-inertial flow of a yield stress fluid around spheres. The analysis was conducted for two spheres with different surface conditions. Friction laws at their interface have been determined. For the bulk behaviour of the fluid, elastoviscoplasticity and viscoelasticity have also been characterised. The resulting parameters have been used to analyse the experimental results. The drag coefficient was determined with respect to hydrophobic properties and surface roughness. From this determination, a criterion enabling the prediction of a sphere’s stability in a yield stress fluid as a function of the fluid/sphere interfacial properties has been proposed. The kinematic fields have also been measured by PIV. These fields enable the quantification of the velocity fields around the spheres according to the adherence conditions of the fluid. This quantification has enabled the characterisation of the extent and the shape of sheared and static rigid zones. Moreover, the calculations of the drag force due to the shear stresses and the drag force due to the normal stresses have revealed the preponderance of the latter in the total drag force.
Databáze: OpenAIRE