Interfacial instability of liquid films coating the walls of a parallel-plate channel and sheared by a gas flow
Interfacial instability of liquid films coating the walls of a parallel-plate channel and sheared by a gas flow
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涂覆平行板通道壁并被气流剪切的液膜的界面不稳定性
DOI：
10.1007/s10404-018-2111-z
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发表时间：
2016
影响因子：
2.8
通讯作者：
S. Hardt
中科院分区：
文献类型：
--
作者：
Miklós Vécsei;M. Dietzel;S. Hardt
研究了平行板通道壁上覆盖有压力驱动气流沿通道中心面剪切的液膜的稳定性和耦合性。这种薄膜容易受到长波不稳定性的影响。对于足够低的雷诺数和较厚的气层，动力学行为可用两个耦合的非线性偏微分方程组来描述。在材料性质和初始原状液膜厚度相等的条件下，进行了线性稳定性分析。线性分析被用来确定界面失稳的主要原因是剪应力的变化还是作用在界面上的压力梯度。对这种情况下的弱非线性方程的分析表明，系统中不存在与雷诺数为零对应的不稳定性。此外，对于这种配置，发现沿两个界面出现的图案在长时间限制内是相同的，这意味着薄膜是完全同步的。数值研究了一种不同的装置，其中液体膜具有相同的材料性质，但它们的未扰动厚度不同。结果表明，即使在这种构型下，界面波在很长一段时间内仍保持着位相同步和密切相关。这些发现与气体流经带有液体涂层壁面的狭窄管道的情况特别相关。
The stability and coupling of liquid films coating the walls of a parallel-plate channel and sheared by a pressure-driven gas flow along the channel center plane is studied. The films are susceptible to a long-wavelength instability. For sufficiently low Reynolds numbers and thick gas layers, the dynamic behavior is found to be described by two coupled nonlinear partial differential equations. A linear stability analysis is conducted under the condition that the material properties and the initial undisturbed liquid-film thicknesses are equal. The linear analysis is utilized to determine whether the interfaces are predominantly destabilized by the variations of the shear stress or by the pressure gradient acting upon them. The analysis of the weakly nonlinear equations performed for this case shows that instabilities corresponding to a vanishing Reynolds number are absent from the system. Moreover, for this configuration, the patterns emerging along the two interfaces are found to be identical in the long-time limit, implying that the films are fully synchronized. A different setup, where the liquid films have identical material properties but their undisturbed thicknesses differ, is studied numerically. The results show that, even for this configuration, the interfacial waves remain phase-synchronized and closely correlated for an extended period of time. These findings are particularly relevant for gaseous flow through narrow ducts with liquid-coated walls.
影响因子：
5.4
作者：
Eifert, Alexander;Paulssen, Dorothea;Hardt, Steffen
通讯作者：
Hardt, Steffen