Berlin 2018 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 65: Granular Matter / Contact Dynamics (joint session DY/CPP)

CPP 65.7: Talk

Thursday, March 15, 2018, 11:45–12:00, BH-N 333

Rheology of 3D frictionless spherocylinders — •Dániel B. Nagy¹, Tamás Börzsönyi¹, Philippe Claudin², and Ellák Somfai¹ — ¹Institute for Solid State Physics and Optics, Wigner Research Center for Physics, Hungarian Academy of Sciences, Budapest, Hungary — ²Physique et Mécanique des Milieux Hétérogènes, PMMH UMR 7636 ESPCI - CNRS - Univ. Paris-Diderot - Univ. P.M. Curie, Paris, France

The rheology of dense granular matter is an active domain of research and important both from the fundamental and the applied point of view. In the absence of large gradients, a successful approach formulates the constitutive equation as an effective friction µ, dependent only on the dimensionless inertial number I. In our work we used 3D numerical simulations to extend this formalism to frictionless spherocylinders. As in the case of spherical particles, the effective friction is an increasing function of the inertial number. We systematically investigated the dependence of µ on the particle aspect ratio Q, as well as that of the normal stress differences, the volume fraction and the coordination number. We found an interesting non-monotonic behavior of the quasistatic friction coefficient with Q: from the spherical case Q = 1, it first sharply increases, reaches a maximum around Q ≈ 1.05, and then gently decreases until Q=3, passing its initial value at Q ≈ 2. We provided a microscopic interpretation for this through the analysis of the distribution of dissipative contacts around the particles. For slightly elongated grains the dissipation density is highest in their central cylindrical band, whereas at larger Q this moves to their caps.