Cycle of segregation patterns in vertically vibrated binary granular mixtures

A new phenomenon of granular segregation is observed, in which the binary granular mixture submitted to the vertically vibration behaves in cyclic segregation patterns which switches between the Brazil nut, reverse Brazil nut and sandwich patterns with a frequency that accelerates with time. The rule of cycing is investigated, and the phase diagram is depicted. The new phenomenon is qualitatively explained in terms of the collision, friction and air dissipation, and it was experimentally verified that the cycling of segregation patterns has close relation with the presence of air.