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Settling of an asymmetric dumbbell in a quiescent fluid

Published online by Cambridge University Press:  03 August 2016

F. Candelier
Affiliation:
IUSTI, CNRS, UMR 7343, University of Aix-Marseille, 13013 Marseille, CEDEX 13, France
B. Mehlig*
Affiliation:
Department of Physics, Gothenburg University, SE-41296 Gothenburg, Sweden
*
Email address for correspondence: Bernhard.Mehlig@physics.gu.se

Abstract

We compute the hydrodynamic torque on a dumbbell (two spheres linked by a massless rigid rod) settling in a quiescent fluid at small but finite Reynolds number. The spheres have the same mass densities but different sizes. When the sizes are quite different, the dumbbell settles vertically, aligned with the direction of gravity, the largest sphere first. But when the size difference is sufficiently small, then its steady-state angle is determined by a competition between the size difference and the Reynolds number. When the sizes of the spheres are exactly equal, then fluid inertia causes the dumbbell to settle in a horizontal orientation.

Type
Papers
Copyright
© 2016 Cambridge University Press 

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