Insight in shear banding under transient flow.
Insight in shear banding under transient flow.
复制标题
洞察瞬态流下的剪切带。
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
J. Berret
中科院分区：
文献类型：
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作者：
J. Decruppe;S. Lerouge;J. Berret
本文报道了表面活性剂粘弹性溶液在瞬态剪切流场中的流变-光学行为。突然施加阶梯状剪切速率，我们记录液体的瞬态物理特性，即，剪切应力σ、透射强度I（t）和散射图案。在流动开始时，剪切应力显示出一个重要的过冲，然后是阻尼振荡，这也出现在强度分布中。然后，S形弛豫过程使液体进入最终的稳定状态。在该第一阶段期间，还可以观察到由于增强的浓度波动引起的扩散图案。流动开始后不久，在移动壁附近出现一个精细的各向异性层，但其宽度在松弛过程结束后开始显著增加。当激光束穿过该带时，可以观察到衍射图案，表明它是由小的子带形成的，其特征宽度在100微米的量级。
The rheo-optical behavior of a viscoelastic solution of a surfactant subjected to transient shear flows is reported. A steplike shear rate is suddenly imposed and we record the transient physical characteristics of the liquid, i.e., the shear stress sigma, the transmitted intensity I(t), and the scattering pattern. At the inception of the flow the shear stress shows an important overshoot followed by damped oscillations which also appear in the intensity profile. Then a sigmoïdal relaxation process brings the liquid in its final steady state. During this first phase, the diffusion pattern due to enhanced concentration fluctuations can also be observed. A fine anisotropic layer appears near the moving wall shortly after the inception of the flow, but its width starts to increase significantly well after the end of the relaxation process. When the laser beam travels through this band a diffraction pattern can be observed indicating that it is formed by small subbands, the characteristic width of which is in the order of 100 micro m.