Linear instability of two-fluid Taylor–Couette flow in the presence of surfactant
Linear instability of two-fluid Taylor–Couette flow in the presence of surfactant
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DOI：
10.1017/s002211200999406x
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发表时间：
2010-03
影响因子：
3.7
通讯作者：
Jie Peng;K. Zhu
中科院分区：
文献类型：
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作者：
Jie Peng;K. Zhu
采用简正模线性分析和余能分析方法，研究了不可溶表面活性剂对同心双流体Taylor-Couette流环缝中径向分层不混溶液体的离心性和剪切不稳定性的影响。假设界面与圆柱体同心。引力效应被忽略了。综合考虑了密度和粘度分层、表面张力、表面活性剂浓度分布和Taylor-Couette剪切的影响。各种物理不稳定机制之间的竞争和相互作用导致的不稳定特征是主要关注的问题。得到了雷诺数(Re1)/轴向波数(K)平面上具有上下分支的中性曲线。确定了一个参数窗口，在该窗口中流动是线性稳定的。表面活性剂浓度梯度引起的Marangoni牵引力稳定了轴对称扰动，但在基本Couette剪切流的存在下，引发了与非轴对称模式相对应的不稳定性。外筒同向旋转对扩大稳定区域有稳定作用，在反旋转情况下稳定区域缩小。
The effect of an insoluble surfactant on the centrifugal and shear instability of a pair of radially stratified immiscible liquids in the annular gap between concentric two-fluid Taylor–Couette flow is investigated by a normal-mode linear analysis and complementary energy analysis. The interface is assumed to be concentric with the cylinders. The gravitational effects are ignored. Influences of density and viscosity stratification, surface tension, surfactant concentration distribution and Taylor–Couette shearing are considered comprehensively. The instability characteristics due to competition and interaction between various physical instability mechanisms are of principal concern. Neutral curves with upper and lower branches in the Reynolds number (Re1)/axial wavenumber (k) plane are obtained. A window of parameters is identified in which the flow is linearly stable. The Marangoni traction force caused by the gradient of surfactant concentration stabilizes the axisymmetric perturbations but initiates an instability corresponding to non-axisymmetric modes in the presence of basic Couette shearing flow. Co-rotation of the outer cylinder has a stabilizing effect in expanding the stable region, which dwindles in the counter-rotation situation.