DYNAMICS OF A MECHANICAL INTERFACE IN SHEAR-BANDED FLOW
DYNAMICS OF A MECHANICAL INTERFACE IN SHEAR-BANDED FLOW
复制标题
剪切带流中机械界面的动力学
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
X. Yuan
中科院分区：
文献类型：
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作者：
X. Yuan
在 Johnson-Segalman (JS) 模型本构不稳定性加上牛顿应力的背景下，研究了蠕虫状胶束溶液的剪切带。我们将变形率张量的高阶梯度项纳入 JS 模型中，以研究剪切带流中机械界面的动力学。新模型的二维建模是通过一般拉格朗日-欧拉方案进行的。在不稳定区域内，我们的结果表明，新项在选择稳态剪切应力方面起着重要作用，并且所选应力与标称剪切速率无关。达到稳态的过渡期可能比 JS 流体的固有弛豫时间长得多。我们已经验证了机械亚稳态状态存在的实验证据，在该亚稳态状态下可能会出现流量曲线的滞后现象。该模型捕捉了剪切带流实验结果的许多特征。
Shear banding of wormlike micelle solution has been studied in the context of constitutive instability of the Johnson-Segalman (JS) model plus Newtonian stress. We have incorporated a higher-order gradient term of the deformation-rate tensor into the JS model for investigating the dynamics of a mechanical interface in shear-banded flow. Two-dimensional modelling of the new model has been carried out by a general Lagrangian-Eulerian scheme. Within the unstable region, our results show that the new term plays an important role in selecting steady-state shear stress and the selected stress is independent of the nominal shear rate. The transit period of reaching the steady state can be much longer than the intrinsic relaxation time of the JS fluid. We have verified the experimental evidence on the existence of mechanical metastable regime, over which hysteresis in flow curve might occur. The model captures many features of experimental results on shear banded flow.