Standing jumps in shallow granular flows down smooth inclines
Ressauts stationnaires dans les écoulements granulaires peu épais sur fond lisse
Faug, T. ; Childs, P. ; Wyburn, E. ; Einav, I.
Type de document
Article de revue scientifique à comité de lecture
Affiliation de l'auteur
IRSTEA GRENOBLE UR ETGR FRA ; UNIVERSITY OF SYDNEY AUS ; UNIVERSITY OF SYDNEY AUS ; UNIVERSITY OF SYDNEY AUS
Résumé / Abstract
The shapes of standing jumps formed in shallow granular flows down an inclined smooth-based chute are analysed in detail, by varying both the slope and mass discharge. Laboratory tests and analytic jump solutions highlight two important transitions. First, for dense flows at high mass discharge, we observe a transition between steep jumps and more diffuse jumps. The traditional shallow-water equation offers a valid prediction for the thickness of the steep water-like jumps. Diffuse frictional jumps require a more general equation accounting for the forces acting inside the jump volume. Second, moving from dense to dilute flows produces another transition between incompressible and compressible jumps. The observed jump height decrease may be reproduced for a more dilute incoming flow by including experimentally measured density variation in the jump equation. Finally, we briefly discuss the likely relevance to avalanche protection dam design that currently utilises traditional shock equations for incompressible frictionless fluids.
Physics of Fluids, vol. 27, num. 7, 22 p.