Influence of bottom roughness and ambient pressure conditions on the emplacement of experimental dam-break granular flows

Abstract

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 = 75µm) or coarse (d = 150µm) grains in a flume with different bottom roughness (δ) and vacuum degrees (P * ). Our results reveal an increase of the flow run-out as d/δ decreases for fine d = 75µm-particles, and run-out decreases with the dimensionless ambient pressure (P * ) for a given d/δ. In contrast, the run-out

Rheology of hail-debris flow and implications in flow mobility

“…In debris flows, friction is dominated by fluid stress (viscous stress, the same as water flows), and fluidparticle (drag) and particle-particle interactions (Coulombic friction and collisions) [1,2]. Apparent flow friction angles are significantly lower than typical repose angles, resulting in larger run-out distances than expected [3,4]. Friction reductions are attributed to different mechanisms, as particles interacting with bottom roughness or particle-fluid interactions causing fluidization [1,4].…”

“…Apparent flow friction angles are significantly lower than typical repose angles, resulting in larger run-out distances than expected [3,4]. Friction reductions are attributed to different mechanisms, as particles interacting with bottom roughness or particle-fluid interactions causing fluidization [1,4]. Single phase numerical models introduce friction mechanisms in as part of the use resistance law by ad-hoc rheological formulation.…”