翻訳と辞書
Words near each other
・ Hersleb Vogt
・ Hersman
・ Hersman, Illinois
・ Herschel Walker trade
・ Herschel wedge
・ Herschel Weingrod
・ Herschel Whitfield Arant
・ Herschel, Eastern Cape
・ Herschel, Saskatchewan
・ Herschell Carrousel Factory Museum
・ Herschell Gordon Lewis
・ Herschell Turner
・ Herschelle Gibbs
・ Herschell–Spillman Motor Company Complex
・ Herschell–Spillman Noah's Ark Carousel
Herschel–Bulkley fluid
・ Herschend Family Entertainment
・ Herscher High School
・ Herscher, Illinois
・ Herschlag
・ Herschmann
・ Herschweiler-Pettersheim
・ Herscovici classification
・ Hersden
・ Hersdorf
・ Herse
・ Herse (moon)
・ Hersee
・ Hersek Headland
・ Hersekzade Ahmed Pasha


Dictionary Lists
翻訳と辞書 辞書検索 [ 開発暫定版 ]
スポンサード リンク

Herschel–Bulkley fluid : ウィキペディア英語版
Herschel–Bulkley fluid
The Herschel–Bulkley fluid is a generalized model of a non-Newtonian fluid, in which the strain experienced by the fluid is related to the stress in a complicated, non-linear way. Three parameters characterize this relationship: the consistency ''k'', the flow index ''n'', and the yield shear stress \tau_0. The consistency is a simple constant of proportionality, while the flow index measures the degree to which the fluid is shear-thinning or shear-thickening. Ordinary paint is one example of a shear-thinning fluid, while oobleck provides one realization of a shear-thickening fluid. Finally, the yield stress quantifies the amount of stress that the fluid may experience before it yields and begins to flow.
This non-Newtonian fluid model was introduced by Winslow Herschel and Ronald Bulkley in 1926.
==Definition==

The constitutive equation of the Herschel-Bulkley model is commonly written as
:\tau = \tau_ + k \dot ^
where \tau is the shear stress, \dot the shear rate, \tau_ the yield stress, k the consistency index, and n the flow index. If \tau < \tau_ the Herschel-Bulkley fluid behaves as a solid, otherwise it behaves as a fluid. For n<1 the fluid is shear-thinning, whereas for n>1 the fluid is shear-thickening. If n=1 and \tau_0=0, this model reduces to the Newtonian fluid.
As a generalized Newtonian fluid model, the effective viscosity is given as 〔K. C. Sahu, P. Valluri, P. D. M. Spelt, and O. K. Matar (2007) 'Linear instability of pressure-driven channel flow of a Newtonian and a Herschel–Bulkley fluid' Phys. Fluids 19, 122101〕
:
\mu_
\mu_0, & |\dot| \leq \dot_0 \\
k |\dot|^+\tau_0 |\dot|^ , & |\dot| \geq \dot_0
\end

The limiting viscosity \mu_0 is chosen such that \mu_0=k \dot_0^+\tau_0 \dot_0^. A large limiting viscosity means that the fluid will only flow in response to a large applied force. This feature captures the Bingham-type behaviour of the fluid.
The viscous stress tensor is given, in the usual way, as a viscosity, multiplied by the rate-of-strain tensor
:\tau_ = 2 \mu_|) E_ = \mu_|) \left(\frac+\frac\right),
where the magnitude of the shear rate is given by
:|\dot|=\sqrt}.
The magnitude of the shear rate is an isotropic approximation, and it is coupled with the second invariant of the rate-of-strain tensor
:II_E = tr(E_ E^) = E_E^.

抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)
ウィキペディアで「Herschel–Bulkley fluid」の詳細全文を読む



スポンサード リンク
翻訳と辞書 : 翻訳のためのインターネットリソース

Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.