Lee Ji San, Weon Byung Mook, Park Su Ji, Kim Ji Tae, Pyo Jaeyeon, Fezzaa Kamel, Je Jung Ho
X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, South Korea.
Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea.
Sci Rep. 2020 Apr 1;10(1):5790. doi: 10.1038/s41598-020-62705-5.
We elucidate the evolution of the entrained air in drop impact on a wide range of liquids, using ultrafast X-ray phase-contrast imaging. We elaborate the retraction mechanism of the entrapped air film in terms of liquid viscosity. We found the criterion for deciding if the entrapped air evolves into single or double bubbles, as determined by competition among inertia, capillarity, and viscosity. Low viscosity and low surface tension induce a small daughter droplet encapsulated by a larger air shell bubble, forming an antibubble. We demonstrate a phase diagram for air evolution regarding hydrodynamics.
我们使用超快X射线相衬成像技术，阐明了液滴撞击多种液体时夹带空气的演变过程。我们根据液体粘度阐述了截留气膜的回缩机制。我们发现了由惯性、毛细作用和粘度之间的竞争决定截留空气是演变成单个气泡还是双气泡的判据。低粘度和低表面张力会导致一个较小的子液滴被一个较大的气壳气泡包裹，形成一个反气泡。我们展示了一个关于空气演变的流体动力学相图。
