TY - JOUR
T1 - Avalanche stratification - Experimental tests of the "metastable wedge" and "continuous flow" models
AU - Swanson, M. E.
AU - Landreman, M.
AU - Michel, J.
AU - Kakalios, J.
PY - 2000
Y1 - 2000
N2 - When an initially homogeneous binary mixture of granular media such as fine and coarse sand is poured near the closed edge of a "quasi-two-dimensional" Hele-Shaw cell consisting of two vertical transparent plates held a narrow distance apart, the mixture spontaneously forms alternating segregated layers. Experimental measurements of this stratification effect are reported in order to determine which model, one which suggests that segregation only occurs when the granular material contained within a metastable heap between the critical and maximum angle of repose avalanches down the free surface, or one for which the segregation results from smaller particles becoming trapped in the top surface and being removed from the moving layer during continuous flow. The result reported here indicate that the Metastable Wedge model provides a natural explanation for the initial mixed zone which precedes the formation of the layers, while the Continuous Flow model explains the observed upward moving kink of segregated material for higher granular flux rates, and that both mechansims are necessary in order to understand the observed pairing of segregated layersfor intermediate flow rates and cell separations.
AB - When an initially homogeneous binary mixture of granular media such as fine and coarse sand is poured near the closed edge of a "quasi-two-dimensional" Hele-Shaw cell consisting of two vertical transparent plates held a narrow distance apart, the mixture spontaneously forms alternating segregated layers. Experimental measurements of this stratification effect are reported in order to determine which model, one which suggests that segregation only occurs when the granular material contained within a metastable heap between the critical and maximum angle of repose avalanches down the free surface, or one for which the segregation results from smaller particles becoming trapped in the top surface and being removed from the moving layer during continuous flow. The result reported here indicate that the Metastable Wedge model provides a natural explanation for the initial mixed zone which precedes the formation of the layers, while the Continuous Flow model explains the observed upward moving kink of segregated material for higher granular flux rates, and that both mechansims are necessary in order to understand the observed pairing of segregated layersfor intermediate flow rates and cell separations.
UR - http://www.scopus.com/inward/record.url?scp=0034428489&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0034428489&partnerID=8YFLogxK
U2 - 10.1557/proc-627-bb2.6
DO - 10.1557/proc-627-bb2.6
M3 - Article
AN - SCOPUS:0034428489
SN - 0272-9172
VL - 627
SP - BB261-BB268
JO - Materials Research Society Symposium - Proceedings
JF - Materials Research Society Symposium - Proceedings
ER -