本研究利用水滴碰撞傾斜超疏水薄膜探討碰撞角度和韋伯數對液滴破裂行為的影響。利用高速攝影機觀察液滴側視及俯視的運動過程，研究結果顯示，當韋伯數和撞擊角度增大時，液滴表現出複雜的破裂模式。特別是在碰撞角度90°時，液滴的破裂行為最為複雜，初期產生冠狀飛濺，隨後擴展至最大面積後於回縮過程中發生破裂，最終形成向上噴射。從破裂液滴數量分析中發現，減少碰撞角度能明顯降低撞擊後所產生的破裂液滴數量。進一步分析得知，液滴尺寸和表面潤濕性對破裂數量有顯著影響，較小液滴在低碰撞角度下易於破裂，而較大液滴則在較高碰撞角度下表現出更多的破裂行為。此外，液滴的最大拉伸長度在碰撞角度30°時達到最大，隨著碰撞角度減少，拉伸長度反而減少。而液滴擴展時的橫向最大寬度及邊緣液指數量皆呈現單調性增長。整體而言，研究表明液滴的撞擊行為受到碰撞角度、韋伯數、液滴尺寸和表面潤濕性等因素的綜合影響，並揭示液滴在不同碰撞角度下的變化。;This study investigates the effects of impact angle and Weber number on droplet breakup behavior by examining the impact of water droplets on inclined superhydrophobic thin films. High-speed cameras were used to observe the droplet dynamics from both side and top views. The results show that as the Weber number and impact angle increase, the droplets exhibit more complex breakup modes. In particular, at impact angle of 90°, the breakup behavior is most intricate, beginning with a crown-shaped splash, followed by expansion to the maximum spreading diameter, subsequent breakup during the receding phase, and eventually upward jetting. Analysis of the number of fragmented droplets reveals that reducing the impact angle significantly decreases the number of secondary droplets produced after impact. Further analysis indicates that droplet size and surface wettability have a notable influence on the extent of breakup: smaller droplets tend to break up more easily at lower impact angles, while larger droplets show more pronounced fragmentation at higher impact angles. Additionally, the maximum elongation length of the droplet is observed at a 30° impact angle and decreases with further reduction in angle. The maximum lateral spreading width of the droplet and the number of rim liquid fingers both exhibit monotonic variation during the spreading phase. Overall, the study demonstrates that droplet impact dynamics are governed by a combination of factors including impact angle, Weber number, droplet size, and surface wettability, and reveals the behavioral variations of droplets under different impact conditions.
