A dilation-driven vortex flow in sheared granular materials explains a rheometric anomaly
Data(s) |
2016
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Resumo |
Granular flows occur widely in nature and industry, yet a continuum description that captures their important features is yet not at hand. Recent experiments on granular materials sheared in a cylindrical Couette device revealed a puzzling anomaly, wherein all components of the stress rise nearly exponentially with depth. Here we show, using particle dynamics simulations and imaging experiments, that the stress anomaly arises from a remarkable vortex flow. For the entire range of fill heights explored, we observe a single toroidal vortex that spans the entire Couette cell and whose sense is opposite to the uppermost Taylor vortex in a fluid. We show that the vortex is driven by a combination of shear-induced dilation, a phenomenon that has no analogue in fluids, and gravity flow. Dilatancy is an important feature of granular mechanics, but not adequately incorporated in existing models. |
Formato |
application/pdf |
Identificador |
http://eprints.iisc.ernet.in/53560/1/Nat_Com_7_10630_2016.pdf Krishnaraj, KP and Nott, Prabhu R (2016) A dilation-driven vortex flow in sheared granular materials explains a rheometric anomaly. In: NATURE COMMUNICATIONS, 7 . |
Publicador |
NATURE PUBLISHING GROUP |
Relação |
http://dx.doi.org/10.1038/ncomms10630 http://eprints.iisc.ernet.in/53560/ |
Palavras-Chave | #Chemical Engineering |
Tipo |
Journal Article PeerReviewed |