Wave evolution on a falling film
Wave evolution on a falling film
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DOI：
10.1146/annurev.fl.26.010194.000535
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发表时间：
1994
影响因子：
27.7
通讯作者：
Hsueh-Chia Chang
中科院分区：
文献类型：
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作者：
Hsueh-Chia Chang
自40年代末卡皮察父子在软禁期间进行的开创性实验以来（卡皮察和卡皮察，1949），下落薄膜上的波演化引起了许多研究人员的兴趣。它的主要吸引力之一是它的简单性-它是一个开放的流动流体动力学不稳定性，发生在非常低的流速。因此，它可以用最简单的实验装置来研究，这显然是卡皮查的一个重要因素。然而，它产生了丰富的频谱迷人的波动动力学，包括一个非常独特的和实验良好的特征序列的非线性二次跃迁，开始与选定的单色干扰，并最终导致非平稳和宽带（在频率和波数）“湍流”波动动力学。（这里的湍流与不规则时空流动可互换使用。虽然这种向“界面湍流”或“时空混沌”的转变乍一看似乎与其他经典不稳定性非常相似，但最近发现了一些微妙但重要的差异。这些二次跃迁背后的相关非线性机制是本综述的重点。我们将主要讨论自由下落的垂直薄膜上的过渡。倾斜平面上的波浪动力学与垂直极限非常相似，大多数实验和理论都集中在后者。对于垂直油膜，问题由两个独立的无量纲参数定义，我们更喜欢使用Reynolds的俄罗斯惯例
Since the pioneering experiment by the father-son team of the Kapitza family during their house arrest in the late forties (Kapitza & Kapitza 1949), wave evolution on a falling film has intrigued many researchers. One of its main attractions is its simplicity-it is an open-flow hydrodynamic instability that occurs at very low flow rates. It can hence be studied with the simplest experimental apparatus, an obviously important factor for the Kapitzas. Yet, it yields a rich spectrum of fascinating wave dynamics, including a very unique and experimentally well-characterized sequence of nonlinear secondary transitions that begins with a selected monochromatic disturbance and leads eventually to nonstationary and broad-banded (in both frequency and wave number) "turbulent" wave dynamics. (Turbu lence here is used interchangeably with irregular spatio-temporal fluc tuations.) While this transition to "interfacial turbulence" or "spatio temporal chaos" seems to be quite analogous to other classical instabilities at first glance, there are subtle but important differences that have recently come to light. The pertinent nonlinear mechanisms behind these secondary transitions are the focus of the present review. We shall be mostly concerned with transitions on a free-falling vertical film. Wave dynamics on an inclined plane is quite analogous to the vertical limit and most experiments and theories have focused on the latter. For the vertical film, the problem is defined by two independent dimensionless parameters and we prefer the Russian convention of using the Reynolds