Pattern formation of frictional fingers in a gravitational potential

Jon Alm Eriksen (1, 2) , Renaud Toussaint (2, 1) , Knut Jørgen Måløy (1) , Eirik G. Flekkøy (1) , Olivier Galland (3) , Bjørnar Sandnes (4)

1 Department of Physics [Oslo]
2 IPGS - Institut de physique du globe de Strasbourg
3 PGP - Physics of Geological Processes [Oslo]
4 Swansea University

Aligned finger structures, with a characteristic width, emerge during the slow drainage of a liquid-granular mixture in a tilted Hele-Shaw cell. A transition from vertical to horizontal alignment of the finger structures is observed as the tilting angle and the granular density are varied.An analytical model is presented, demonstrating that the alignment properties are the result of the competition between fluctuating granular stresses and the hydrostatic pressure. The dynamics is reproduced in simulations.We also show how the system explains patterns observed in nature, created during the early stages of a dike formation.

Mots clés: granular; fluid; multiphasic; dyke; experiment; modelling; numerical

Domaines: Matière Molle [cond-mat.soft]; Mécanique des fluides [physics.class-ph]; Mécanique des matériaux [physics.class-ph]; Géophysique [physics.geo-ph]; Géomorphologie; Hydrologie; Volcanologie

Jon Alm Eriksen, Renaud Toussaint, Knut Jørgen Måløy, Eirik G. Flekkøy, Olivier Galland, et al.. Pattern formation of frictional fingers in a gravitational potential. Physical Review Fluids, 2018, 3 (1), pp.013801. ⟨10.1103/PhysRevFluids.3.013801⟩. ⟨hal-01685526⟩