2025-07-21 ニューヨーク大学（NYU）
A vortex ring of water traveling in a tank gets reflected off a water-air interface. Credit: John Zhuang Su et al., NYU Shanghai
＜関連情報＞
- https://www.nyu.edu/about/news-publications/news/2025/july/how-do-water-rings–bounce—new-discovery-answers-decades-old-q.html
- https://journals.aps.org/prfluids/abstract/10.1103/dg4m-hbts
水と空気の界面における渦輪の反射 Reflection of vortex rings at a water-air interface
Zhuang Su, Christiana Mavroyiakoumou, and Jun Zhang
Physical Review Fluids Published: 21 July, 2025
DOI: https://doi.org/10.1103/dg4m-hbts
Abstract
We experimentally investigate how vortex rings, generated and propagating within a water tank, interact with the water-air interface. Near-perfect reflections of these vortex rings occur when they approach the interface at a sufficiently large incident angle. To understand this interaction, we employ a vortex-sheet-vortex-pair model in numerical simulations, which captures the essential dynamics. Additionally, a simplified model based on the conservation of flux or momentum provides further insight into the mechanism behind the vortex-ring reflection. Through combined approaches—experimentation, numerical simulation, and detailed analysis—we gain a deeper understanding of how vortex rings interact with free boundaries.
