An experimental study of rivulet instabilities in centrifugal spin coating of viscous Newtonian and non‐Newtonian fluids
An experimental study of rivulet instabilities in centrifugal spin coating of viscous Newtonian and non‐Newtonian fluids
复制标题
粘性牛顿和非牛顿流体离心旋涂中细流不稳定性的实验研究
DOI：
10.1063/1.868263
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发表时间：
1994
影响因子：
4.6
通讯作者：
G. Homsy
中科院分区：
文献类型：
--
作者：
N. Fraysse;G. Homsy
本文对离心驱动小流的发生和演化进行了实验研究，旨在探讨不同实验条件（液滴体积和旋转频率）、液体润湿特性（表面张力和接触角）以及流体粘弹性对离心驱动小流不稳定性的影响。该装置可以连续观察衬底脉冲自旋后的液滴形状，并通过数字图像分析对其进行分析。流动表现出一个开始时间，或者，等效地，一个临界半径，在此之前，液滴轴对称扩散。将液滴扩散的数据与润滑理论的简单预测进行了比较。测量的方位角波数和不稳定性的增长速率与Troian等人的线性稳定性分析很好地吻合。[左10,25(1989)]，只要临界半径取自实验本身。发现最不稳定的波长与液滴大小和腐蚀无关。
An experimental study on the onset and evolution of centrifugally driven rivulets is presented, which aims to investigate the influence on the instability of various experimental conditions (drop volume and rotational frequency), the wetting properties of the liquid (surface tension and contact angle), and fluid viscoelasticity. The apparatus allows continuous observation of the drop shapes following an impulsive spin‐up of the substrate, and these are analyzed by digital image analysis. The flows exhibit an onset time, or, equivalently, a critical radius, before which the drop spreads axisymmetrically. Data on drop spreading are compared with simple predictions of lubrication theory. The measured azimuthal wave number and growth rate of the instability are in good agreement with the linear stability analysis of Troian et al. [Europhys. Lett. 10, 25 (1989)], as long as the critical radius is taken from the experiment itself. The most unstable wavelength is found to be independent of both drop size and rot...