MOTION OF INTRUDERS WITHIN A VIBRATED GRANULAR BED Iván Sánchez ijsanche@ivic.gob.ve Centro de Física, Instituto Venezolano de Investigaciones Científicas, Caracas 1020-A, Venezuela Karol Asencio Diego Maza Iker Zuriguel Departamento de Física y Matemática Aplicada, Universidad de Navarra, Pamplona 31008, Spain Abstract. We present experimental results of the motion of cylindrical and spherical intruders immersed in a bulk of grains contained in a quasi-two-dimensional rectangular box undergoing vertical sinusoidal oscillation. For spherical intruders we study the effect of the container size on the rising/sinking time of intruders with two different densities (greater and lower than the bulk density of the granular material). For cylindrical intruders we study the behavior of intruders with three different densities (above, equal and below the bulk density of the granular material) in a Brazil nut and a reverse buoyancy regime. Studying the intruder’s motion inside a single period of oscillation reveals interesting aspects of the segregation behavior. In the Brazil nut regime all three intruders ascend in a non-linear way, with only quantitative differences. In the reverse buoyancy regime, different density intruders show qualitatively different behavior. Keywords: granular material, segregation, reverse buoyancy, brazil nut effect 1. INTRODUCTION Segregation occupies a privileged spot in the study of granular materials due to its importance in industrial applications such as rotating drums, hoppers, mixers, pipes, and in vertically vibrated media (for this last case, Kudrolli's review [1] is a good starting point). There are several mechanisms behind intruder segregation (arc formation, buoyancy, air drag, percolation, inertia, convection and combination of some of the above). The relevance of each mechanism depends on the particular configuration (granular material, container geometry, INGENIERÍA Y CIENCIAS APLICADAS: MODELOS MATEMÁTICOS Y COMPUTACIONALES E. Dávila, J. Del Río, M. Cerrolaza, R. Chacón (Editores) © 2014 SVMNI Todos los derechos reservados