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 formf∝d^−1/2.