Posted on 02/03/2023 1:15:14 PM PST by Red Badger
Bubbles Red Arrow
Five centuries ago, Leonardo da Vinci observed air bubbles deviating from a straight path in a zigzag or spiral motion. However, the cause of this periodic motion remained unknown until now.
Researchers from the universities of Seville and Bristol have solved the mystery surrounding the unsteady path of an air bubble rising in water. Professors Miguel Ángel Herrada of the University of Seville and Jens G. Eggers of the University of Bristol have uncovered a mechanism that explains the erratic movement of bubbles rising in water. The findings, published in the prestigious journal Proceedings of the National Academy of Sciences, could provide insights into the behavior of particles that fall between solid and gas states.
Leonardo da Vinci observed five centuries ago that air bubbles, if big enough, periodically deviate in a zigzag or spiral from a straight-line movement. However, no quantitative description of the phenomenon or physical mechanism to explain this periodic motion had ever been found.
Leonardo’s sketch showing the spiral motion of an ascending bubble (from his manuscript known as the Codex Leicester). Credit: Universidad de Sevilla
The authors of this new paper have developed a numerical discretization technique to characterize precisely the bubble’s air-water interface, which enables them to simulate its motion and explore its stability. Their simulations closely match high-precision measurements of unsteady bubble motion and show that bubbles deviate from a straight trajectory in water when their spherical radius exceeds 0.926 millimeters, a result within 2% of experimental values obtained with ultrapure water in the 90s.
The researchers propose a mechanism for the instability of the bubble trajectory whereby periodic tilting of the bubble changes its curvature, thus affecting the upward velocity and causing a wobble in the bubble’s trajectory, tilting up the side of the bubble whose curvature has increased. Then, as the fluid moves faster and the fluid pressure falls around the high-curvature surface, the pressure imbalance returns the bubble to its original position, restarting the periodic cycle.
Reference: “Path instability of an air bubble rising in water” by Miguel A. Herrada and Jens G. Eggers, 17 January 2023, Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.2216830120
Inner surface tension...?
> I have always wondered why in carbonated drinks, beer, etc, bubble originate at a certain spot over and over for no apparent reason....................
Surface impurities in the container.
“What causes the periodic tilting?”
__________________________
THAT’s my question.
LOL
In all seriousness that’s the question I was wondering....
I didn’t see this addressed in the article, but, isn’t this just Brownian Motion on a larger level?
https://en.m.wikipedia.org/wiki/Codex_Leicester
“I have always wondered why in carbonated drinks, beer, etc, bubble originate at a certain spot over and over for no apparent reason....................”
I’m sure there is a government grant out there for the taking to figure that out.
You don’t know that.
If you find his bong, let me know:>)
I wonder why my spearmint loses its flavor on the bedpost overnight
Bubbles form when the dissolved gas, carbon dioxide in this example, is super saturated. The gas comes out of solution, forming bubbles, more easily at surface defects and asperities. The bubbles form less easily on smooth surfaces, and even less easily in the bulk liquid, away from any surface. The surface defects typically are always in the same place, so bubbles will preferentially form there, which is what you see.
"and when Ben Casey meets Kildare, that's called, a paradox."
Secondary and tertiary usage
Well I will sleep better knowing this.
Leonardo da Vinci’s Second Paradox
The friction of the air against the the water cause the bubble to start to spin.....................
AKA, a dirty glass.......................🤦♀️
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