Darcy's Law without Friction in Active Nematic Rheology.
Phys Rev Lett
; 124(18): 187801, 2020 May 08.
Article
en En
| MEDLINE
| ID: mdl-32441954
We study the dynamics of a contractile active nematic fluid subjected to a Poiseuille flow. In a quasi-1D geometry, we find that the linear rheology of this material is reminiscent of Darcy's law in complex fluids, with a pluglike flow decaying to zero over a well-defined "permeation" length. As a result, the viscosity increases with size, but never diverges, thereby evading the yield stress predicted by previous theories. We find strong shear thinning controlled by an active Ericksen number quantifying the ratio between external pressure difference and internal active stresses. In 2D, the increase of linear regime viscosity with size only persists up to a critical length beyond which we observe active turbulent patterns, with very low apparent viscosity. The ratio between the critical and permeation length determining the stability of the Darcy regime can be made indefinitely large by varying the flow aligning parameter or magnitude of nematic order.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Phys Rev Lett
Año:
2020
Tipo del documento:
Article
País de afiliación:
Reino Unido
Pais de publicación:
Estados Unidos