Non-local rheology of dense granular flows

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Abstract

The rheology of dense granular flows is studied numerically in a shear cell controlled at constant pressure and shear stress, confined between two granular shear flows. We show that a liquid state can be achieved even far below the yield stress, whose flow can be described with the same rheology as above the yield stress. A non-local constitutive relation is derived from dimensional analysis through a gradient expansion and calibrated using the spatial relaxation of velocity profiles observed under homogeneous stresses. Both for frictional and frictionless grains, the relaxation length is found to diverge as the inverse square root of the distance to the yield point, on both sides of that point. We also make use of a micro-rheometer to determine the influence of a distant shear band on the local rheological behaviour. Finally, we compare various approaches based on different non-local constitutive relations and choices for the fluidity parameter. We emphasise that, to discriminate between the different approaches proposed in the literature, one has to go beyond the predictions derived from linearisation around a uniform stress profile, such as that obtained in a simple shear cell. We argue that future tests can be based on the nature of the chosen fluidity parameter, and the related boundary conditions, as well as the hypothesis made to derive the models and the dynamical mechanisms underlying their dynamics.

Detaljer

Författare
  • Mehdi Bouzid
  • Martin Trulsson
  • Adrien Izzet
  • Adeline Favier De Coulomb
  • Philippe Claudin
  • Eric Clément
  • Bruno Andreotti
Enheter & grupper
Externa organisationer
  • Georgetown University
  • Paris Diderot University
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Materialteknik
Originalspråkengelska
Artikelnummer11013
TidskriftEPJ Web of Conferences
Volym140
StatusPublished - 2017 jun 30
PublikationskategoriForskning
Peer review utfördJa