Nicolas Brodu, Renaud Delannay, Alexandre Valance, Patrick Richard
By means of extensive numerical simulations, we discovered new regimes in channeled granular flows. These regimes emerge from the destabilization of unidirectional flows upon increase of mass holdup and inclination angle. They are characterized by non-trivial internal structures, with secondary flows and/or an heterogeneous mass distribution. The newly identified states include flows with a pair of rolls, superposed rolls, a basal ordered layer topped by secondary flows, and states where a dense core is supported by a gaseous phase. Besides, the supported regimes exhibit striking behaviors at high mass holdup such as symmetry breaking leading to periodic oscillations of the dense core. Interestingly, these different regimes are shown to obey a universal scaling law for the mass flow rate as a function of the mass hold-up. These new states provide a unique set of 3D flow regimes on which granular rheological models can be tested and open perspectives for interpreting geophysical granular flows.
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http://arxiv.org/abs/1210.7478
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