2002/11/06 by G. Gutiérrez, Gutiérrez, G., O. Pozo +9
Engineering · Environmental Science · #FOS: Physical sciences #Granular flow and fluidized beds #Landslides and related hazards #Lattice Boltzmann Simulation Studies #Soft Condensed Matter (cond-mat.soft)
paper · pdf · doi:10.48550/arxiv.cond-mat/0211116
openalex publication_date 2002/11/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Large objects, immersed in a homogeneous granular system, migrate when subjected to vibrations. Under certain conditions large heavy objects rise and similar light ones sink to the bottom. This is called reverse buoyancy. We report an experimental study of this singular behavior, for a large sphere immersed in a deep granular bed. A simple mechanism is proposed to describe the motion of a sphere, inside a vertically vibrated granular system. When reverse buoyancy is observed, the measured vertical velocity of the immersed object, as a function of its density, shows a simple behavior. With a one-dimensional mechanical model that takes into account a buoyancy force and the frictional drag, we obtain the rising velocity for heavy objects and the sinking rate for light ones. The model yields a very good qualitative and quantitative agreement with the experiment.