Shape matters: Competing mechanisms of particle shape segregation

D. Hernández-Delfin, D. R. Tunuguntla, T. Weinhart, R. C. Hidalgo, A. R. Thornton

Research output: Contribution to journalArticleAcademicpeer-review

1 Downloads (Pure)


It is well known that granular mixtures that differ in size or shape segregate when sheared. In the past, two mechanisms have been proposed to describe this effect, and it is unclear if both exist. To settle this question, we consider a bidisperse mixture of spheroids of equal volume in a rotating drum, where the two mechanisms are predicted to act in opposite directions. We present evidence that there are two distinct segregation mechanisms driven by relative overstress. Additionally, we showed that, for nonspherical particles, these two mechanisms (kinetic and gravity) can act in different directions leading to a competition between the effects of the two. As a result, the segregation intensity varies nonmonotonically as a function of aspect ratio (AR), and, at specific points, the segregation direction changes for both prolate and oblate spheroids, explaining the surprising segregation reversal previously reported. Consistent with previous results, we found that the kinetic mechanism is dominant for (almost) spherical particles. Furthermore, for moderate aspect ratios, the kinetic mechanism is responsible for the spherical particles' segregation to the periphery of the drum, and the gravity mechanism plays only a minor role. Whereas, at the extreme values of AR, the gravity mechanism notably increases and overtakes its kinetic counterpart.

Original languageEnglish
Article number054614
JournalPhysical Review E
Issue number5
Publication statusPublished - 15 Nov 2022


  • 2023 OA procedure


Dive into the research topics of 'Shape matters: Competing mechanisms of particle shape segregation'. Together they form a unique fingerprint.

Cite this