@article{fdi:010046767,
  title = {{E}xperimental observations of water-like behavior of initially fluidized, dam break granular flows and their relevance for the propagation of ash-rich pyroclastic flows},
  author = {{R}oche, {O}livier and {M}ontserrat, {S}. and {N}ino, {Y}. and {T}amburrino, {A}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he physics of ash-rich pyroclastic flows were investigated through laboratory dam break experiments using both granular material and water. {F}lows of glass beads of 60-90 mu m in diameter generated from the release of initially fluidized, slightly expanded (2.5-4.5%) columns behave as their inertial water counterparts for most of their emplacement. {F}or a range of initial column height to length ratios of 0.5-3, both types of flows propagate in three stages, controlled by the time scale of column free fall similar to(h(0)/g)(1/2), where h(0) denotes column height and g denotes gravitational acceleration. {F}lows first accelerate as the column collapses. {T}ransition to a second, constant velocity phase occurs at a time t/(h(0)/g)(1/2) similar to 1.5. {T}he flow velocity is then {U} similar to root 2(gh(0))(1/2), larger than that for dry (initially nonfluidized) granular flows. {T}ransition to a last, third phase occurs at t/(h(0)/g)(1/2) similar to 4. {G}ranular flow behavior then departs from that of water flows as the former steadily decelerates and the front position varies as t(1/3), as in dry flows. {M}otion ceases at t/(h(0)/g) 1/2 similar to 6.5 with normalized runout x/h(0) similar to 5.5-6. {T}he equivalent behavior of water and highly concentrated granular flows up to the end of the second phase indicates a similar overall bulk resistance, although mechanisms of energy dissipation in both cases would be different. {I}nterstitial air-particle viscous interactions can be dominant and generate pore fluid pressure sufficient to confer a fluid-inertial behavior to the dense granular flows before they enter a granular-frictional regime at late stages. {E}fficient gas-particle interactions in dense, ash-rich pyroclastic flows may promote a water-like behavior during most of their propagation.},
  keywords = {},
  booktitle = {},
  journal = {{J}ournal of {G}eophysical {R}esearch - {S}olid {E}arth},
  volume = {113},
  numero = {{B}12},
  pages = {{B}12203},
  ISSN = {0148-0227},
  year = {2008},
  DOI = {10.1029/2008jb005664},
  URL = {https://www.documentation.ird.fr/hor/fdi:010046767},
}