A foam film propagating in a confined geometry: Analysis via the viscous froth model
A foam film propagating in a confined geometry: Analysis via the viscous froth model
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DOI：
10.1140/epje/i2007-10262-8
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发表时间：
2008-01-01
影响因子：
1.8
通讯作者：
Green, T. E.
中科院分区：
文献类型：
--
作者：
Grassia, P.;Montes-Atenas, G.;Green, T. E.
通过粘性泡沫模型分析了在受限几何形状（即，受限于紧密间隔的顶板和底板之间）中移动的单个膜（典型的泡沫中的膜）。在第一种情况下，膜被认为是直的（从顶板上方观察）但不是平坦的。相反，它在横跨限制板的方向上是弯曲的（具有圆弧横截面）。该曲率导致膜的最大可能的稳定传播速度，其特征在于弯曲膜切向地与顶板和底板相遇。接下来，膜被认为在通道中传播（即，在顶板和底板与侧壁之间，侧壁间隔超过顶板和底板的侧壁间隔）。膜现在沿着沿着以及横跨顶板和底板弯曲。沿板的曲率沿着由作用在通道侧壁边界上的粘性阻力引起。最大稳定传播速度不变，但现在也可以与切向地与通道侧壁相遇的膜相关联，如果从顶板上方观察膜，则应该容易观察到这种情况。然而，从上面观察，膜不需要呈现为圆弧。相反，膜可以沿其长度的大部分沿着是相对直的，其中曲率被推入侧壁处的边界层中。
A single film (typical of a film in a foam) moving in a confined geometry (i.e. confined between closely spaced top and bottom plates) is analysed via the viscous froth model. In the first instance the film is considered to be straight (as viewed from above the top plate) but is not flat. Instead it is curved (with a circular arc cross-section) in the direction across the confining plates. This curvature leads to a maximal possible steady propagation velocity for the film, which is characterised by the curved film meeting the top and bottom plates tangentially. Next the film is considered to propagate in a channel (i.e. between top and bottom plates and sidewalls, with the sidewall separation exceeding that of the top and bottom plates). The film is now curved along as well as across the top and bottom plates. Curvature along the plates arises from viscous drag forces on the channel sidewall boundaries. The maximum steady propagation velocity is unchanged, but can now also be associated with films meeting channel sidewalls tangentially, a situation which should be readily observable if the film is viewed from above the top plate. Observed from above, however, the film need not appear as an arc of a circle. Instead the film may be relatively straight along much of its length, with curvature pushed into boundary layers at the sidewalls.