Affiliation：Kyoto University

Abstract：Droplet impingement has long been a hot topic among researchers for its ubiquitousity in industrial applications. Effect on the outcome of the impingement pertaining to ambient gas pressure and surface wettability are focused on in this research. 3D detailed numerical simulations, with gas-liquid interface tracked by Coupled Level-set and Volume of Fluid (CLSVOF) method, are performed to explore the possibility of utilizing 3D numerical simulations for the investigation of droplet impingement on dry surfaces. Our research found that 3D numerical simulations can reproduce the phenomena related to droplet impingement including a splash. Wettability influences the outcome of droplet impingement at the initial stage (i.e., when the droplet initially touches down on the surface and generates a thin film from the three-phase contact line) by triggering a larger average velocity magnitude in the generated thin film, together with a stronger variation on the azimuthal velocity distribution generated by the impingement immediately after the touchdown onto the surface. Ambient pressure significantly prompts the splash during the spreading of droplets on the surface after the impingement. A vortex above the tip of the droplet is observed in the investigation. The generation and extension of filaments after the impingement, which is usually referred to as fingering for its shape, is significantly suppressed under high ambient pressure.

Publication related to your research:
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• Tianyi Wei, Zhicheng Yuan, Abhishek L. Pillai, Ryoichi Kurose, “Numerical investigation of droplet splash on flat surfaces: Influence of surface wettability”, 第59 回日本伝熱シンポジウム講演論文集, May. 2022.
• Tianyi Wei, Abhishek L. Pillai, Ryoichi Kurose, “Numerical Investigation Regarding Influence of Wettability on Inertia Dominated Droplet Splash”, 日本流体力学会 年会2022 講演論文集, Sep. 2022.
• Tianyi Wei, Abhishek L. Pillai, Ryoichi Kurose, “Influence of Ambient Pressure on Droplet Splash Bahavior”, 日本機械学会第100 期流体工学部門講演会 講演論文集, Nov. 2022.