@article{fdi:010062516,
  title = {{E}xperimental study of dense pyroclastic density currents using sustained, gas-fluidized granular flows},
  author = {{R}owley, {P}. {J}. and {R}oche, {O}livier and {D}ruitt, {T}. {H}. and {C}as, {R}.},
  editor = {},
  language = {{ENG}},
  abstract = {{W}e present the results of laboratory experiments on the behaviour of sustained, dense granular flows in a horizontal flume, in which high-gas pore pressure was maintained throughout the flow duration by continuous injection of gas through the flume base. {T}he flows were fed by a sustained (0.5-30 s) supply of fine (75 +/- 15 mu m) particles from a hopper; the falling particles impacted an impingement surface at concentrations of similar to 3 to 45 %, where they densified rapidly to generate horizontally moving, dense granular flows. {W}hen the gas supplied through the flume base was below the minimum fluidization velocity of the particles (i.e. aerated flow conditions), three flow phases were identified: (i) an initial dilute spray of particles travelling at 1-2 ms-1, followed by (ii) a dense granular flow travelling at 0.5-1 m s-1, then by (iii) sustained aggradation of the deposit by a prolonged succession of thin flow pulses. {T}he maximum runout of the phase 2 flow was linearly dependent on the initial mass flux, and the frontal velocity had a square-root dependence on mass flux. {T}he frontal propagation speed during phase 3 had a linear relationship with mass flux. {T}he total mass of particles released had no significant control on either flow velocity or runout in any of the phases. {H}igh-frequency flow unsteadiness during phase 3 generated deposit architectures with progradational and retrogradational packages and multiple internal erosive contacts. {W}hen the gas supplied through the flume base was equal to the minimum fluidization velocity of the particles (i.e. fluidized flow conditions), the flows remained within phase 2 for their entire runout, no deposit formed and the particles ran off the end of the flume. {S}ustained granular flows differ significantly from instantaneous flows generated by lock-exchange mechanisms, in that the sustained flows generate (by prolonged progressive aggradation) deposits that are much thicker than the flowing layer of particles at any given moment. {T}he experiments offer a first attempt to investigate the physics of the sustained pyroclastic flows that generate thick, voluminous ignimbrites.},
  keywords = {{F}luidization ; {P}yroclastic flow ; {D}ensity current ; {P}ore pressure ; {S}ustained supply ; {E}xperiments},
  booktitle = {},
  journal = {{B}ulletin of {V}olcanology},
  volume = {76},
  numero = {9},
  pages = {art. 855 [13 ]},
  ISSN = {0258-8900},
  year = {2014},
  DOI = {10.1007/s00445-014-0855-1},
  URL = {https://www.documentation.ird.fr/hor/fdi:010062516},
}