@article{fdi:010081507,
  title = {{E}xperimental assessment of the effective friction at the base of granular chute flows on a smooth incline},
  author = {{R}oche, {O}livier and van den {W}ildenberg, {S}. and {V}alance, {A}. and {D}elannay, {R}. and {M}angeney, {A}. and {C}orna, {L}. and {L}atchimy, {T}.},
  editor = {},
  language = {{ENG}},
  abstract = {{W}e report on direct measurements of the basal force components for granular material flowing down a smooth incline. {W}e investigate granular flows for a large range of inclination angles from theta = 13.4 degrees to 83.6 degrees and various gate openings of the chute. {W}e find that the effective basal friction coefficient mu({B}), obtained from the ratio of the longitudinal force to the normal one, exhibits a systematic increase with increasing slope angle and a significant weakening with increasing particle holdup {H} (the depth-integrated particle volume fraction). {A}t low angles, the basal friction is slightly less than or equal to tan theta. {T}he deviation from tan theta can be interpreted as a contribution from the sidewall to the overall friction. {A}t larger angles, the basal friction mu({B}) saturates at an asymptotic value that is dependent on the gate opening of the chute. {I}mportantly, our data confirm the outcomes of recent discrete numerical simulations. {F}irst, for steady and fully developed flows as well as for moderately accelerated ones, the variation of the basal friction can be captured through a unique dimensionless number, the {F}roude number {F}r, defined as {F}r = ({U}) over bar/(g{H}cos theta)(1/2), where ({U}) over bar is the mean flow velocity. {S}econd, the mean velocity scales with the particle holdup {H} with a power exponent close to 1/4, contrasting with the {B}agnold scaling (({U}) over bar similar to {H}-3/(2)).},
  keywords = {},
  booktitle = {},
  journal = {{P}hysical {R}eview {E}},
  volume = {103},
  numero = {4},
  pages = {042905 [12 ]},
  ISSN = {2470-0045},
  year = {2021},
  DOI = {10.1103/{P}hys{R}ev{E}.103.042905},
  URL = {https://www.documentation.ird.fr/hor/fdi:010081507},
}