| dc.description.abstract | This study conducted impact experiments with different impact angles and Weber numbers on droplets, combining high-speed cameras to capture both top-down and side-view images to explore the relationship between the geometric characteristics and motion conditions of droplet impacts. The images obtained from the experiments were analyzed using image processing, website reading, and MATLAB′s built-in computation and plotting programs to investigate the expansion process and the relationships between the shape, aspect ratio, and other factors of the droplet impact. The results indicate that for decane droplets impacting various flat surfaces, the Weber number has little effect on the aspect ratio, and inertia has no significant impact on shape change. However, for water droplets on different plates, at low Weber numbers and different impact angles, the aspect ratio and sinϕ values are inconsistent, indicating that surface tension and contact angle have a significant impact on the shape. Under different Weber numbers and equilibrium contact angles, the droplet expansion area is constrained by surface tension and surface energy, especially at low impact angles and high/low Weber numbers, where the expansion area is less than 90° impact angles. The study also validated the maximum spreading factor using previous models. Additionally, the study finds that the dynamic behavior of water droplets on Teflon plates is significantly influenced by We and ϕ, exhibiting receding breakup non-monotonic transition. As We and ϕvary, droplets display different patterns during expansion and receding, including the formation of liquid fingers, sliding, edge instabilities of the liquid film, breakup liquid fingers into smaller droplets, and receding. | en_US |