Rise-Time Regimes of a Large Sphere in Vibrated Bulk Solids

We report experiments on the rise time T of a single large sphere within a sinusoidally vibrated bed (amplitude a) of uniform particles (diameter d). At fixed acceleration, we identify three distinct behavioral regimes both from visual observations and from the typical increase of T with frequency f. We observe two convective regimes separated by a critical frequency and, for low a and high f, a ``nonconvective'' regime. In the latter, the bed crystallizes and a size dependent rise is evidenced. We show the relevance of the nondimensional parameter $a/d$ and deduce a scaling law of the form f∝d^-1/2.