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arXiv 1502.01301cond-mat.soft
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幂律流体在流体动力润滑状态下的滑动摩擦

Sliding friction in the hydrodynamic lubrication regime for a power-law fluid

Patrick B. Warren

AI总结:

本文通过标度分析研究幂律流体在流体动力润滑状态下的滑动摩擦,论证当幂律指数 n<1/2 时剪切稀化区域力学不稳定,导致 Stribeck 曲线不连续并可能出现迟滞,同时讨论了法向应力、流动瞬态和拉伸黏度的影响及其在剪切增稠中的应用。

摘要:

针对流体动力润滑状态下滑动摩擦中的载荷平衡开展了一项标度分析,特别关注结构化液体典型的幂律剪切稀化行为。文中论证,当幂律指数 n < 1/2 时(其中 n 是将剪切应力与剪切速率联系起来的指数),剪切稀化区域在力学上是不稳定的。因此,Stribeck(摩擦)曲线应当是不连续的,并可能存在迟滞现象。进一步分析表明,法向应力和流动瞬态(应力过冲)不会破坏这一基本图像,尽管它们可能在较高剪切速率下提供稳定化机制。除非 Trouton 比很大,否则拉伸黏度预计也不重要。文中指出了该方法在非布朗颗粒悬浮液剪切增稠中的可能应用。

英文摘要:

A scaling analysis is undertaken for the load balance in sliding friction in the hydrodynamic lubrication regime, with a particular emphasis on power-law shear-thinning typical of a structured liquid. It is argued that the shear-thinning regime is mechanically unstable if the power-law index n < 1/2, where n is the exponent that relates the shear stress to the shear rate. Consequently the Stribeck (friction) curve should be discontinuous, with possible hysteresis. Further analysis suggests that normal stress and flow transience (stress overshoot) do not destroy this basic picture, although they may provide stabilising mechanisms at higher shear rates. Extensional viscosity is also expected to be insignificant unless the Trouton ratio is large. A possible application to shear thickening in non-Brownian particulate suspensions is indicated.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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