The water-enhanced Brazil nut effect

• Published in: Europhysics letters Vol. 91; no. 5; p. 54001
• Main Authors: Clement, C. P, Pacheco-Martinez, H. A, Swift, M. R, King, P. J
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01-09-2010; EPS, SIF, EDP Sciences and IOP Publishing
• Subjects: 45.70.Mg; 47.55.Kf; Beads; Computational fluid dynamics; Fluid flow; Fluids; Liquids; Mathematical models; Monitors; Steels
• ISSN: 0295-5075; 1286-4854
• DOI: 10.1209/0295-5075/91/54001

It is well known that a large dense intruder may rise to the surface of a vibrated granular bed, the Brazil nut effect. In this paper we describe a water-enhanced Brazil nut effect which occurs when the vibrated granular bed is fully immersed in a liquid. We use a bed of glass beads immersed in water and monitor the behaviour of a large steel intruder as the system is vibrated vertically. To aid our understanding, we have developed numerical simulations to model this system and provide detailed information on the fluid and grain motion. The mechanism responsible for the rapid rise of the intruder is shown to be fluid-enhanced ratcheting rather than simple differential drag.