Three-dimensional dynamics of falling films in the presence of insoluble surfactants
Three-dimensional dynamics of falling films in the presence of insoluble surfactants
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DOI：
10.1017/jfm.2020.796
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发表时间：
2020-05
影响因子：
3.7
通讯作者：
A. Batchvarov;L. Kahouadji;C. Constante-Amores;Gabriel Farah Norões Gonçalves;Seungwon Shin;J. Chergui;D. Juric;R. Craster;O. Matar
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文献类型：
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作者：
A. Batchvarov;L. Kahouadji;C. Constante-Amores;Gabriel Farah Norões Gonçalves;Seungwon Shin;J. Chergui;D. Juric;R. Craster;O. Matar
摘要研究了不溶性表面活性剂对垂直下落液膜波动动力学的影响。我们使用三维数值模拟，并采用混合界面跟踪/水平集方法，考虑到Marangoni应力引起的界面表面活性剂浓度梯度。我们对无表面缺陷的三维波拓扑的演化的数值预测针对Park & Nosoko的实验工作（AIChE J.，第49卷，2003年，第100页。2715-2727）。添加表面活性剂被发现显着影响马蹄形波的发展。在低Marangoni数，我们表明，波前展向振荡，最终获得准二维形状。此外，发现Marangoni应力的存在抑制了行波和先前的毛细波结构的峰值。在高Marangoni数，观察到一个接近完全的界面硬化。
Abstract We study the effect of insoluble surfactants on the wave dynamics of vertically falling liquid films. We use three-dimensional numerical simulations and employ a hybrid interface-tracking/level-set method, taking into account Marangoni stresses induced by gradients of interfacial surfactant concentration. Our numerical predictions for the evolution of the surfactant-free, three-dimensional wave topology are validated against the experimental work of Park & Nosoko (AIChE J., vol. 49, 2003, pp. 2715–2727). The addition of surfactants is found to influence significantly the development of horseshoe-shaped waves. At low Marangoni numbers, we show that the wave fronts exhibit spanwise oscillations before eventually acquiring a quasi-two-dimensional shape. In addition, the presence of Marangoni stresses is found to suppress the peaks of the travelling waves and preceding capillary wave structures. At high Marangoni numbers, a near-complete rigidification of the interface is observed.