Annular Films Dewetting

Another novel feature displayed in cylindrical geometry is that the interface curvamre 

In Ref 159, the authors explain that this strong increase may be linked to the distribution of the energy dissipation inside the bump located between the contact line and the static constant thickness film. As seen in Fig. 23, these bumps have a strongly asymmetrical shape with a higher slope near the contact line than at the junction with the static film. 

Very recent experimental results are superimposed in Fig. 24 with blue markers, those data correspond to the dewettmg capillary number measured when films of various water-glycerol solutions dewet on PVC fibers of two different radii. It is observed that they follow the same trend as the values for capillary tubes. To date, there is no complete explanation for this behavior yet. 

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Figure 23 displays a sequence of pictures of an annular film of glycerol—water solution dewetting inside a PVC capillary tube and in Fig. 24 the experimental variation of Ca with h/a is shown with triangles. As observed, the data corroborate the theoretical increasing trend, but the experimental enhancement of the dewettmg velocity is much larger than the predicted one. 

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