par Bertho, Yann 
;Brunet, Th;Giorgiutti-Dauphiné, Fŕed́erique;Hulin, Jean Pierre
Référence Europhysics letters, 67, 6, page (955-961)
Publication Publié, 2004-09
;Brunet, Th;Giorgiutti-Dauphiné, Fŕed́erique;Hulin, Jean PierreRéférence Europhysics letters, 67, 6, page (955-961)
Publication Publié, 2004-09
Article révisé par les pairs
| Résumé : | A significant dependence on the relative humidity H for the apparent mass (Mapp) measured at the bottom of a granular packing inside a vertical tube in relative motion is demonstrated experimentally. While the predictions of Janssen's model are verified for all values of H investigated (25% ≤ H ≤ 80%), Mapp increases with time towards a limiting value at high relative humidities (H ≥ 60%), but remains constant at lower ones (H = 25%). The corresponding Janssen length A is nearly independent of the tube velocity for H ≥ 60% but decreases markedly for H = 25%. Other differences are observed on the motion of individual beads in the packing: for H = 25%, they are almost motionless, while the mean particle fraction of the packing remains constant; for H ≥ 60% the bead motion is much more significant and the mean particle fraction decreases. The dependence of these results on the bead diameter and their interpretation in terms of the influence of capillary forces are discussed. |
