1.
Phys Rev E Stat Nonlin Soft Matter Phys
; 68(1 Pt 1): 012301, 2003 Jul.
Artigo
em Inglês
| MEDLINE
| ID: mdl-12935182
RESUMO
A large heavy object may rise to the top of a bed of smaller particles under the influence of vertical vibration, the "Brazil nut effect." Recently it has been noted that interstitial air can influence the Brazil nut rise time. Here we report that the air movement induced by vertical vibration produces a very strong Brazil nut effect for fine granular beds. We use a porous-bottomed box to investigate the mechanism responsible for this effect and to demonstrate that it is related to the piling of fine beds, first reported by Chladni and studied by Faraday. Both effects are due to the strong interaction of the fine particles with the air, as it is forced through the bed by the vibration.