Artículos de revistas
Enhanced run-out of dam-break granular flows caused by initial fluidization and initial material expansion
Fecha
2016Registro en:
Granular Matter (2016) 18:11
1434-5021
DOI: 10.1007/s10035-016-0604-6
Autor
Montserrat Michelini, Santiago
Tamburrino Tavantzis, Aldo
Roche, Oliver
Niño Campos, Yarko
Ihle Bascuñán, Christian
Institución
Resumen
We report results of the run-out of experimental
dam-break flows in a horizontal channel generated from
the collapse of columns of fine (75 μm) particles fluidized
at various degrees. We find that the flow run-out (x) made
dimensionless by the initial column length (xo) is a power
function of the initial column height-to-length ratio (r ),
as shown in previous works with non-fluidized flows. The
run-out of flows initially fluidized at different degrees is
accounted by x/xo = αr n. For initially non-fluidized flows,
our values of α are significantly higher than those reported
earlier for flows of coarser granular material (>0.15 mm),
showing that finely grained flows have longer run-outs compared
to their coarser counterparts. The coefficient α is a
function of the initial degree of fluidization, with a higher
growth above 93 % of fluidization, which coincides with the
onset of bed expansion, and it accounts for a flow run-out
increase being up to more than twice that of non-fluidized
flows. The parameter α is well correlated with the amount of
initial bed expansion, which undergoes a sharp transition at
high degrees of fluidization that has shown to be an important mechanism for reducing flow friction. Our results are consistent
with earlier findings that showed that bed expansion
significantly increases pore pressure diffusion timescales in
static columns, suggesting that the long run-out of initially
expanded finely grained flows is due to their ability to diffuse
pore pressure slowly.