@article{fdi:010046766,
  title = {{P}ropagation and hindered settling of laboratory ash flows - art. no. {B}02202},
  author = {{G}irolami, {L}. and {D}ruitt, {T}. {H}. and {R}oche, {O}livier and {K}hrabrykh, {Z}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he fluidal behavior of pyroclastic flows is commonly attributed to high gas pore pressures and associated fluidization effects. {W}e carried out experiments on flows of fluidized volcanic ash at 170 degrees {C}, which is hot enough to reduce cohesive effects of moisture. {T}he flows were generated in a 3- m- long, horizontal lock- exchange flume. {T}he ash was fluidized and expanded uniformly in the flume reservoir by up to 43% above loose packing and was then released. {E}ach flow defluidized progressively down the flume until motion ceased. {I}nitial expansion {E} and initial height h(0) were varied independently of one another. {T}he flows traveled in a laminar manner. {F}low fronts exhibited three main phases of transport: ( 1) a brief initial phase of gravitational slumping, ( 2) a dominant, approximately constant velocity phase, and (3) a brief stopping phase. {P}hase 2 frontal velocities scaled with root gh(0), like other types of dam- break flow. {D}eposition from initially expanded flows took place by progressive sediment aggradation at a rate that was independent of distance and varied only with {E}. {D}espite rates of shear up to 80 s(-1), aggradation rates were identical to those determined independently, at the same value of {E}, in quasi-static collapse tests. {S}edimentation caused the flows to thin progressively during transit until they ran out of volume. {T}he dynamics were governed to a first order by two dimensionless parameters: (1) the initial aspect ratio h(0)/x(0) in the lock reservoir and (2) the ratio t(sett)/t(grav) of two timescales: a particle settling time t(sett) and a gravitational acceleration time t(grav).},
  keywords = {},
  booktitle = {},
  journal = {{J}ournal of {G}eophysical {R}esearch {S}olid {E}arth},
  volume = {113},
  numero = {{B}2},
  pages = {{NIL}_1--{NIL}_13},
  ISSN = {0148-0227},
  year = {2008},
  DOI = {10.1029/2007{JB}005074},
  URL = {https://www.documentation.ird.fr/hor/fdi:010046766},
}