INVESTIGADORES
UÑAC Rodolfo Omar
congresos y reuniones científicas
Título:
Segregation by flow in quasi 2D piles
Autor/es:
RODRIGUEZ, D.; BENITO, J.G.; I. IPPOLITO; HULIN, J.P.; A. M. VIDALES; R. O. UÑAC
Lugar:
Carlos Paz
Reunión:
Workshop; XIII Latin American Workshop on Nonlinear Phenomena; 2013
Resumen:
Stratication, mixing and layering processes have been studied during the build-up of quasi-2D
piles from two dierent mixtures of grains of dierent diameters (1mm glass beads and 3mm
glass beads or coriander seeds). The domains of existence of the dierent ow regimes obtained
for the two sets of beads as a function of the relative volume ow rates of the two species
and of the fall heights have been compared and the inuence of the ow regimes on the time
dependence of the mean slope of the pile has been studied. The experiments, show in particular,
that segregation may be complete when the larger grains are coriander seeds while some amount
of mixing is always observed for glass beads, even though the ratio between the sizes of the
particles is the same in both cases. The layering regime could be observed using glass beads
of same spherical geometry and density but with two dierent diameters: it is is characterized
by the large amplitude of the variations of the slope of the pile. No layering is observed when
coriander seeds of same size replace glass beads as the large particles. The local processes
involved in these regimes have been analyzed quantitatively : the characteristic velocities of
the dierent types of displacements of the grains have in particular been determined from
spatiotemporal diagrams of the variation with time of the prole of the free surface. Avalanches
were only observed in the layering regime and play an important part in the development of
the layers.