Eur. Phys. J. E (2012) 35: 106
https://doi.org/10.1140/epje/i2012-12106-x

Regular Article

Reverse buoyancy in a vibrated granular bed: Computer simulations

¹ Departamento de Física, Universidad Simón Bolívar, Apartado 89000, Caracas 1080-A, Venezuela
² Centro de Física, Instituto Venezolano de Investigaciones Científicas, AP 21827, Caracas 1020-A, Venezuela
³ Academia Nacional de Investigación y Desarrollo A.C., C.P. 62040, Cuernavaca, Morelos, México
⁴ Laboratoire de Physique des Solides Bâtiment 510, CNRS UMR8502, Université Paris-Sud, F-91405, Orsay, France

^* e-mail: vidler@usb.ve
^** e-mail: ijsanche@ivic.gob.ve

Received: 6 June 2012
Revised: 11 September 2012
Accepted: 5 October 2012
Published online: 24 October 2012

Abstract

We have performed molecular dynamics simulations of an intruder in a vibrated granular bed including interstitial fluid effects to account for the phenomenon of reverse buoyancy. We show that our model is able to reproduce the overall behaviour observed by previous experimental works and is the first finite-elements simulation to show the sinking of intruders lighter than the granular bed. To further advance our comprehension of this phenomenon, we studied the motion of the intruders in a single vibration cycle with respect to the bottom of the granular column, finding a substantial qualitative difference for heavy and light intruders and we compare these results with experiments using fine-sized glass beads. We show that, though heavy intruders seem unaffected by the force due to the fluid, the effect on light intruders is remarkable.