Abstract
It has been documented since the Renaissance that an air bubble rising in water will deviate from its straight, steady path to perform a periodic zigzag or spiral motion once the bubble is above a critical size. Yet, unsteady bubble rise has resisted quantitative description, and the physical mechanism remains in dispute. Using a numerical mapping technique, we for the first time find quantitative agreement with high-precision measurements of the instability. Our linear stability analysis shows that the straight path of an air bubble in water becomes unstable to a periodic perturbation (a Hopf bifurcation) above a critical spherical radius of R = 0.926 mm, within 2% of the experimental value. While it was previously believed that the bubble’s wake becomes unstable, we now demonstrate a new mechanism, based on the interplay between flow and bubble deformation.
| Original language | English |
|---|---|
| Article number | e2216830120 |
| Number of pages | 3 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Volume | 120 |
| Issue number | 4 |
| Early online date | 17 Jan 2023 |
| DOIs | |
| Publication status | Published - 24 Jan 2023 |
Bibliographical note
Publisher Copyright:Copyright © 2023 the Author(s). Published by PNAS. This open access article is distributed under Creative Commons Attribution License 4.0 (CC BY).