@article{fdi:010081448,
  title = {{G}ranular mixture deflation and generation of pore fluid pressure at the impact zone of a pyroclastic fountain : experimental insights},
  author = {{F}ries, {A}. and {R}oche, {O}livier and {C}arazzo, {G}.},
  editor = {},
  language = {{ENG}},
  abstract = {{W}e present the results of analogue laboratory experiments on pyroclastic fountain collapse. {M}ixtures of air and glass beads ranging in size around 75 +/- 15 mu m, with {S}tokes number of similar to 10(-3)-10(1) and representative of 0.1-1 mm sized particles in nature, were released from a hopper at heights of 0.45-2.95 m above the base of a horizontal channel. {F}ree fall caused continuous dilation of the granular material and led to mean particle concentrations of similar to 9-36 vol%, with concentration inversely proportional to drop height, before the particles impacted the channel base. {D}ecoupling between the particles and the ambient air upon impact caused deflation of the mixture, which then propagated laterally as a dense granular flow overridden by a dilute suspension. {M}easurements at the impingement surface revealed that pore fluid pressure, generated through high air-particle relative velocity during deflation, counterbalanced up to similar to 50% of the weight of the emerging granular flow. {T}he runout distance of the dense flow increased linearly with the fall height, similar to published results on unidirectional flows generated from collapse of packed granular columns. {T}his suggests that the runout of flows resulting from release of granular material is controlled essentially by conversion of potential to kinetic energy and that the initial particle concentration is a second order parameter. {W}e conclude that fountaining of pyroclastic material containing large amounts of particles with {S}tokes numbers of the order 10(-3)-10(1) can generate dense pyroclastic flows with some degree of pore fluid pressure.},
  keywords = {{P}yroclastic fountain ; {P}yroclastic flow ; {E}xperiment ; {P}ore fluid pressure ; {S}tokes number},
  booktitle = {},
  journal = {{J}ournal of {V}olcanology and {G}eothermal {R}esearch},
  volume = {414},
  numero = {},
  pages = {107226 [10 ]},
  ISSN = {0377-0273},
  year = {2021},
  DOI = {10.1016/j.jvolgeores.2021.107226},
  URL = {https://www.documentation.ird.fr/hor/fdi:010081448},
}