Simple model for heterogeneous flows of yield stress fluids.
Simple model for heterogeneous flows of yield stress fluids.
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屈服应力流体非均质流动的简单模型。
DOI：
10.1103/physreve.66.051501
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
F. Lequeux
中科院分区：
文献类型：
--
作者：
G. Picard;A. Ajdari;L. Bocquet;F. Lequeux
各种实验证明剪切屈服应力流体的空间不均匀性。为了解释速度梯度方向的不均匀性，我们使用一个简单的模型，对应于一个非单调的局部流动曲线和研究一个简单的剪切几何。考虑了不同类型的边界条件。在控制宏观剪切应力σ下，我们发现在本体中的均匀流动和滞后的宏观应力-剪切速率曲线。在受控的宏观剪切速率γ i下，在γ i值范围内预测剪切带。对于小的剪切速率，也可以观察到粘滑。这些定性行为对边界条件的变化具有鲁棒性。
Various experiments evidence spatial heterogeneities in sheared yield stress fluids. To account for heterogeneities in the velocity gradient direction, we use a simple model corresponding to a nonmonotonic local flow curve and study a simple shear geometry. Different types of boundary conditions are considered. Under controlled macroscopic shear stress Sigma, we find homogeneous flow in the bulk and a hysteretic macroscopic stress-shear-rate curve. Under controlled macroscopic shear rate Gamma;, shear banding is predicted within a range of values of Gamma;. For small shear rates, stick-slip can also be observed. These qualitative behaviors are robust to changes in the boundary conditions.