Montserrat S. auteur aut IRD Ordonez L. auteur aut IRD Tamburrino A. auteur aut IRD Roche Olivier auteur aut IRD text journalArticle eng text/pdf born digital access Geophysical granular flows occur at the surface of the Earth and other planets with reduced atmospheric pressure. In this paper, we investigate the run-out of dam-break flows of particle-air mixtures with fine (d = 75 mu m) or coarse (d = 150 mu m) grains in a flume with different bottom roughness (delta) and vacuum degrees (P*). Our results reveal an increase of the flow run-out as d/delta decreases for fine d = 75 mu m-particles, and run-out decreases with the dimensionless ambient pressure (P*) for a given d/delta. In contrast, the run-out for coarser d = 150 mu m-particles, is almost invariant respect to P* and d/delta. These results show that autofluidization of fine-grained flows demonstrated by earlier works at ambient pressure also occurs at reduced pressure though being less efficient. Hence, autofluidization is a mechanism, among others, to explain long run-out of geophysical flows in different environments. specialized Dam-break Granular flows Pore pressure Ambient pressure Fluidization Substrate roughness 064 020 23 3 57 [8 ] 2021 1434-5021 https://www.documentation.ird.fr/hor/fdi:010081462 10.1007/s10035-021-01125-2 1434-5021 [F B010081462] https://www.documentation.ird.fr/hor/fdi:010081462 https://www.documentation.ird.fr/intranet/publi/2021-06/010081462.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2021-06-15 2025-02-24 fdi:010081462 fre