Size separation of granular particles

摘要: Granular media differ from other materials in their response to stirring or jostling — unlike two-fluid systems, bi-disperse granular mixtures will separate according particle size when shaken, with large particles rising, a phenomenon termed the 'Brazil-nut effect'1,2,3,4,5,6,7,8. Mounting evidence indicates that differences density affect separation of particles9,10,11. We show here this dependence does not follow steady trend but is non-monotonic and sensitive background air pressure. Our results indicate interstitial must both be considered segregation.