Reversing the Brazil-Nut Effect: Competition between Percolation and Condensation
Abstract
We report on experiments on vertically shaken binary granular mixtures, which separate into their components due to the external excitation. This well-known phenomenon, where large particles rise to the top of the mixture, is called the Brazil-nut effect. Recent theoretical findings predict also a reverse Brazil-nut effect, where large particles sink to the bottom of the container. We choose spherical beads of various diameters and materials in order to observe the transition from Brazil-nut effect to its reverse form. The direction of demixing depends sensitively on the external excitation, so that it is possible to switch between both effects for a given mass density ratio.
- Publication:
-
Physical Review Letters
- Pub Date:
- January 2003
- DOI:
- 10.1103/PhysRevLett.90.014302
- Bibcode:
- 2003PhRvL..90a4302B
- Keywords:
-
- 45.70.Mg;
- 05.65.+b;
- 45.70.Qj;
- Granular flow: mixing segregation and stratification;
- Self-organized systems;
- Pattern formation