Faraday instability of a liquid layer on a lubrication film
Faraday instability of a liquid layer on a lubrication film
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DOI：
10.1017/jfm.2019.684
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发表时间：
2019-09
影响因子：
3.7
通讯作者：
S. Zhao;M. Dietzel;S. Hardt
中科院分区：
文献类型：
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作者：
S. Zhao;M. Dietzel;S. Hardt
研究了具有不同厚度的两个共轭不混溶液体层系统中的法拉第不稳定性。顶层相对较厚并经历短波长不稳定性，而底层较薄并经历长波长不稳定性。这两层通过界面处的运动学和动力学关系耦合。通过线性稳定性分析，可以识别出显着降低失稳阈值的润滑效果。特别是当振动频率较低时，润滑效果会影响谐波和次谐波不稳定模式之间的过渡。研究了底部纳维滑移边界条件的单层系统可以在多大程度上逼近两层系统。在相应的实验中发现，系统的时间周期激励会造成底层的稳态变形。这表明系统的非线性动力学和可逆性的违反。不稳定性发生的实验结果与理论结果之间的良好一致性支撑了线性稳定性分析的有效性。
The Faraday instability in a system of two conjugated immiscible liquid layers with disparate thicknesses is investigated. The top layer is relatively thick and undergoes short-wavelength instabilities, while the bottom layer is thin and undergoes long-wavelength instabilities. The two layers are coupled by the kinematic and dynamic relations at the interface. Through linear stability analysis, a lubrication effect, which significantly reduces the destabilization threshold, is identified. Especially when the vibration frequency is low, the lubrication effect is seen to influence the transition between the harmonic and subharmonic instability modes. It is studied how far the system with two layers can be approximated by a single-layer system with a Navier-slip boundary condition at the bottom. In corresponding experiments it is found that the time-periodic excitation of the system creates a steady-state deformation of the bottom layer. This indicates nonlinear dynamics of the system and the violation of reversibility. The excellent agreement between experimental and theoretical results for the onset of the instability underpins the validity of the linear stability analysis.