Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China.
Phys Rev E. 2017 Jun;95(6-1):063104. doi: 10.1103/PhysRevE.95.063104. Epub 2017 Jun 9.
We demonstrate an internal breakup mechanism for high Weber number drop impact on superhydrophobic surfaces uniformly patterned with submillimeter-scale textures, in which the liquid film ruptures from both interior and rim. The employment of submillimeter-scale posts could help decrease the critical Weber number of internal rupture, due to the small solid fraction and the large dimension ratio between primary structures and droplets. The internal rupture is found to promote more rapid drop bouncing than conventional rebound and rim breakup on superhydrophobic surfaces with small roughness, with a 10%-50% reduction of contact time. The internal rupture results from the film instability inside and the jet instability outside.
我们展示了一种内部破裂机制，用于研究超疏水表面上的高韦伯数液滴冲击，这些表面均匀地带有亚毫米级纹理。在这个机制中，液体薄膜从内部和边缘同时破裂。亚毫米级支柱的使用有助于降低内部破裂的临界韦伯数，这是因为在初级结构和液滴之间，固体分数较小，且尺寸比很大。在小粗糙度的超疏水表面上，与传统的反弹和边缘破裂相比，内部破裂可以促进更快的液滴反弹，接触时间减少了 10%-50%。内部破裂是由内部薄膜不稳定性和外部射流不稳定性共同导致的。
