Segregation-driven organization in chaotic granular flows.
An important industrial problem that provides fascinating puzzles in pattern formation is the tendency for granular mixtures to de-mix or segregate. Small differences in either size or density lead to flow-induced segregation. Similar to fluids, noncohesive granular materials can display chaotic advection; when this happens chaos and segregation compete with each other, giving rise to a wealth of experimental outcomes. Segregated structures, obtained experimentally, display organization in the presence of disorder and are captured by a continuum flow model incorporating collisional diffusion and density-driven segregation. Under certain conditions, structures never settle into a steady shape. This may be the simplest experimental example of a system displaying competition between chaos and order.
Hill
K M
KM
R. R. McCormick School of Engineering and Applied Science, Northwestern University, Evanston, IL 60208, USA.
Khakhar
D V
DV
Gilchrist
J F
JF
McCarthy
J J
JJ
Ottino
J M
JM