Daughter bubble cascades produced by folding of ruptured thin films
Daughter bubble cascades produced by folding of ruptured thin films
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DOI：
10.1038/nature09069
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发表时间：
2010-06-10
期刊：
影响因子：
64.8
通讯作者：
Stone, Howard A.
中科院分区：
文献类型：
--
作者：
Bird, James C.;de Ruiter, Rielle;Stone, Howard A.
薄液膜，如肥皂泡，已经被广泛研究了超过世纪，因为它们很容易形成，并介导了物理，化学和工程中的广泛的传输过程（1-3）。当液-气或固-气界面上的气泡（本文称为界面气泡）破裂时，通常预期气泡消失。更准确地说，破裂的薄膜预计将迅速缩回，直到它成为界面的一部分，这一事件通常发生在毫秒（4-6）内。破裂气泡消失的假设是泡沫演变理论的核心（7），与健康（8）和气候（9）有关，因为气泡破裂是气溶胶液滴的来源（10，11）。在这里，我们表明，对于大范围的流体参数，界面气泡可以创建许多小气泡时，他们破裂，而不是消失。我们证明，无论是实验和数值模拟，破裂的气泡的弯曲膜可以折叠和截留空气，因为它缩回。所得到的被困空气的环形几何形状是不稳定的，导致产生一圈较小的气泡。与较小气泡的较高曲率相关的较高压力增加了气体进入液体的吸收，并增加了破裂引起的气溶胶分散的效率。
Thin liquid films, such as soap bubbles, have been studied extensively for over a century because they are easily formed and mediate a wide range of transport processes in physics, chemistry and engineering(1-3). When a bubble on a liquid-gas or solid-gas interface (referred to herein as an interfacial bubble) ruptures, the general expectation is that the bubble vanishes. More precisely, the ruptured thin film is expected to retract rapidly until it becomes part of the interface, an event that typically occurs within milliseconds(4-6). The assumption that ruptured bubbles vanish is central to theories on foam evolution(7) and relevant to health(8) and climate(9) because bubble rupture is a source for aerosol droplets(10,11). Here we show that for a large range of fluid parameters, interfacial bubbles can create numerous small bubbles when they rupture, rather than vanishing. We demonstrate, both experimentally and numerically, that the curved film of the ruptured bubble can fold and entrap air as it retracts. The resulting toroidal geometry of the trapped air is unstable, leading to the creation of a ring of smaller bubbles. The higher pressure associated with the higher curvature of the smaller bubbles increases the absorption of gas into the liquid, and increases the efficiency of rupture-induced aerosol dispersal.