Dense flow around a sphere moving into a cloud of grains
1 Laboratoire FAST, Université Paris-Sud, CNRS, Université Paris-Saclay, F-91405, Orsay, France
2 LMO, CNRS, Université Paris-Sud, Université Paris-Saclay, F-91405, Orsay, France
3 CMAP, CNRS, Ecole Polytechnique, Université Paris-Saclay, F-91128 Palaiseau, France
4 SPHYNX/SPEC, CEA, CNRS, Université Paris-Saclay, F-91191, Gif-sur-Yvette, France
* e-mail: email@example.com
Published online: 30 June 2017
A bidimensional simulation of a sphere moving at constant velocity into a cloud of smaller spherical grains without gravity is presented with a non-smooth contact dynamics method. A dense granular “cluster” zone of about constant solid fraction builds progressively around the moving sphere until a stationary regime appears with a constant upstream cluster size that increases with the initial solid fraction ϕ0 of the cloud. A detailed analysis of the local strain rate and local stress fields inside the cluster reveals that, despite different spatial variations of strain and stresses, the local friction coeffcient μ appears to depend only on the local inertial number I as well as the local solid fraction ϕ, which means that a local rheology does exist in the present non parallel flow. The key point is that the spatial variations of I inside the cluster does not depend on the sphere velocity and explore only a small range between about 10−2 and 10−1. The influence of sidewalls is then investigated on the flow and the forces.
© The Authors, published by EDP Sciences, 2017
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