| Summary: | 碩士 === 國立臺灣大學 === 應用力學研究所 === 87 === The study of droplet-film-interaction has been restricted as a “demonstration” rather than a “investigation” due to its relatively scattered experimental data in the literature since a long time. A novel method has been introduced in this thesis to produce an accurate and repeatable thin film on the test plate. This method avoids the traditional problems from observing and determining the film thickness, which causes the biggest uncertainty of the experiment due to the capillary meniscus in the liquid-wall-interface.
Main efforts of this work is to figure out the critical splashing threshold for single droplet impinging on different viscous fluid with various film thickness. It is found that the splashing phenomena could be classified as four characteristic regimes. They are (I)very thin liquid film, (II)thin liquid film, (III)thick liquid film and (IV)very thick liquid film regimes. The film thickness has significant influences on the splashing threshold for both (II) and (III) regimes, but not for the other two regimes. The new character in the regimes (I) and (III) are the first time introduced in the literature. Among all regimes, the higher viscosity of the fluid, the higher the critical splashing level. The characteristic curve for the splashing threshold has been completely plotted out for the first time in the literature.
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