Non-local effects reflect the jamming criticality in granular flows of frictionless particles

Hugo Perrin (1) , Matthieu Wyart (2) , Bloen Metzger (1) , Yoël Forterre (1)

1 IUSTI - Institut universitaire des systèmes thermiques industriels
2 UNIL - Université de Lausanne = University of Lausanne

The jamming transition is accompanied by a rich phenomenology, such as hysteresis or non-localeffects, which is still not well understood. Here we experimentally investigate a model frictionlessgranular layer flowing down an inclined plane, as a way to disentangle generic collective effects fromthose arising from frictional interactions. We find that thin frictionless granular layers are devoidof hysteresis, yet the layer stability is increased as it gets thinner. Rheological laws obtained fordifferent layer thicknesses can be collapsed into a unique master curve, supporting that non-localeffects are the consequence of the usual finite-size effects associated to the presence of a criticalpoint. This collapse indicates that the so-called isostatic lengthl∗governs the effect of boundarieson flow, and rules out other propositions made in the past.

Domaines: Physique [physics]

Hugo Perrin, Matthieu Wyart, Bloen Metzger, Yoël Forterre. Non-local effects reflect the jamming criticality in granular flows of frictionless particles. 2021. ⟨hal-03329462⟩