title: Reverse buoyancy in a vibrated granular bed: Computer simulations.
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.
authors.affiliation: Departamento de Física, Universidad Simón Bolívar, Apartado 89000, Caracas 1080-A, Venezuela. vidler@usb.ve
authors.forename: Vladimir
authors.initials: V
authors.lastname: Idler
authors.forename: Iván
authors.initials: I
authors.lastname: Sánchez
authors.forename: Ricardo
authors.initials: R
authors.lastname: Paredes
authors.forename: Robert
authors.initials: R
authors.lastname: Botet
mesh_terms: D000388:Air; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D045604:Extracellular Fluid / Q000378:metabolism; D056004:Molecular Dynamics Simulation; D009068:Movement; D014732:Vibration