Abstract
The article presents the experimental dependences of a macro-contact angle and the diameter of a distilled water drop spreading over solid microstructured surface on surface average roughness (Ra) and fluid flow rate (G). It has been found that at changing G from 0.005 to 0.02 ml/s, the contact angle decreases, and at a liquid flow rate over 0.02 ml/s, it increases. With small values of G (0.005−0.01 ml/s), the drop diameter grows throughout the spreading process. In the range of G from 0.02 to 0.16 ml/s at the final stage of spreading, the contact line pinning, i.e., the diam-eter constancy, has been detected. The hypothesis about the mechanism of the pinning process has been formulated: it is due to the zero sum of all forces acting on the drop (inertia, viscosity, friction, gravity, and surface tension).
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The work was financially supported by the Russian Science Foundation (Project No. 15-19-10025).
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Kuznetsov, G.V., Feoktistov, D.V., Orlova, E.G. et al. The influence of the drop formation rate at spreading over a microstructured surface on the contact angle. Thermophys. Aeromech. 25, 237–244 (2018). https://doi.org/10.1134/S0869864318020099
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DOI: https://doi.org/10.1134/S0869864318020099