Numerical study of the sedimentation of spheroidal particles
2016 (English)In: International Journal of Multiphase Flow, ISSN 0301-9322, E-ISSN 1879-3533, Vol. 87, 16-34 p.Article in journal (Refereed) Published
The gravity-driven motion of rigid particles in a viscous fluid is relevant in many natural and industrial processes, yet this has mainly been investigated for spherical particles. We therefore consider the sedimentation of non-spherical (spheroidal) isolated and particle pairs in a viscous fluid via numerical simulationsusing the Immersed Boundary Method.The simulations performed here show that the critical Galileo number for the onset of secondary motions decreases as the spheroid aspect ratio departs from $1$. Above this critical threshold, oblate particles perform a zigzagging motion whereas prolate particles rotate around the vertical axis while having their broad side facing the falling direction. Instabilities of the vortices in the wake follow when farther increasing the Galileo number.We also study the drafting-kissing-tumbling associated with the settling of particle pairs.We find that the interaction time increases significantly for non-spherical particles and, more interestingly, spheroidal particles are attracted from larger lateral displacements. This has important implications for the estimation of collision kernels and can result in increasing clustering in suspensions of sedimenting spheroids.
Place, publisher, year, edition, pages
2016. Vol. 87, 16-34 p.
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-204157OAI: oai:DiVA.org:kth-204157DiVA: diva2:1084192
QC 201703282017-03-232017-03-232017-03-28Bibliographically approved