EPJ

2024 Impact factor 2.2
EPJ E - Soft Matter and Biological Physics
Soft Matter and Biological Physics


Eur. Phys. J. E 4, 233-239

Vertically shaken column of spheres. Onset of fluidization

S. Renard1, T. Schwager1, T. Pöschel1 and C. Salueña2

1  Humboldt-Universität, Charité, Institut für Biochemie, Monbijoustraße 2, D-10117 Berlin, Germany (http://summa.physik.hu-berlin.de/~kies/)
2  Humboldt-Universität, Institut für Physik, Invalidenstraße 110, D-10115 Berlin, Germany

thorsten@physik.hu-berlin.de

(Received 21 August 2000 and Received in final form 30 October 2000)

Abstract
The onset of surface fluidization of granular material in a vertically vibrated container, $z=A\cos\left(\omega t\right)$, is studied experimentally. Recently, for a column of spheres it has been theoretically found (see T. Pöschel, T. Schwager, C. Salueña, Phys. Rev. E 62, 1361 (2000)) that the particles lose contact if a certain condition for the acceleration amplitude $\ddot{z} \equiv A\omega^2/g = f(\omega)$ holds. This result is in disagreement with other findings where the criterion $\ddot{z}=\ddot{z}_{\rm crit}={const}$ was found to be the criterion of fluidization. We show that for a column of spheres a critical acceleration is not a proper criterion for fluidization and compare the results with theory.

PACS
81.05.Rm - Porous materials; granular materials.
83.70.Fn - Granular solids.


© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2001

Conference announcements