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
PinGGG!.................
I’ve always been baffled by the un-symetric ascent of air bubbles and have spent countless hours pondering same.
Actually, no. I never thought about it.
I’m trying to imagine what that sketch of a squiggly line by Leonardo da Vinci is probably worth.
I have always wondered why in carbonated drinks, beer, etc, bubble originate at a certain spot over and over for no apparent reason....................
Thank you.
that sketch represents the path of a chinese spy balloon when balloon when shot down
unfortunately the bulb burned out and all the 2 new ones I have tried are too hot
LOL!
“I have always wondered why in carbonated drinks, beer, etc, bubble originate at a certain spot over and over for no apparent reason....................”
Same reason why the ‘bubble’ gum is always at the center of a blow pop candy.
Me either. Qualifies a folks who have way too much time on their hands.
DaVinci didn’t even smoke weed
“I’m trying to imagine what that sketch of a squiggly line by Leonardo da Vinci is probably worth.”
That was my first thought also. No sense chasing a bubble when there’s money to follow.
“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”
Seems circular (not a pun). What causes the periodic tilting?
Nobel Prize worthy discovery?
” I’ve always been baffled by the un-symetric ascent of air bubbles and have spent countless hours pondering same. “
Will someone please convince my wife that that’s what I was doing with my head down on the bar last Friday night?
That problem has kept me awake at night. Now I can finally get some sleep.
I better pour a beer to confirm these findings.
“I have always wondered why in carbonated drinks, beer, etc, bubble originate at a certain spot over and over for no apparent reason....................“
…And so we have the Codex Badger…
“What causes the periodic tilting?“
AThe same question that occurred to me. Also why does it not turn on a center axis and thus remain stable? Clearly they didn’t run all of this by FReepers.
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