#Reverse Buoyancy

A granular bed under vibration. We can see the gap in the bottom and a very disperse phase in the top: 2

Grains falling to create the initial state for simulations:

The rising of a hevy intruder 4 times bigger than the grains:

The sinking of a light intruder 8 times bigger than the grains:

Two heavy intruders rising: 4

Two light intruders sinking: 5

Reverse Buoyancy effect: 6

#Granular Leidenfrost Effect

Granular temperature behavior in the granular leidenfrost effect: 7

Granular temperature behavior in the granular leidenfrost effect (another angle): 7.1

Bed's volumetric density profile (low density bottom and high density first bubble). The second bubble is easy to see returning to the main bubble in t~400 and reappearing in t~700. It is always less denser than the main bubble. 8

Granular temperature profile with the second bubble (Very hot bottom and cold first bubble. The second bubble is rather warm: 8

Another example of the double bubble. 8