5 ms·

Supersonic CO2 flow during champagne cork popping

49 points by goatsneez 4y ago

MichaelZuo 4y ago
It's amazing how often effects go to supersonic speeds in everyday life. It really makes sense why our hearing is logarithmic, otherwise we'd all be deaf just from a cork popping.
gus_massa 4y ago
The PDF (free, linked in the page) has nice photos of the popping in page 8 and graphics of the simulation in page 11 and 12.
btilly 4y ago
I can't be the only one wondering this... How many bottles of champagne were purchased for this research, and what was done with their contents afterwards?
- bombcar 4y ago
  > Computational Fluid Dynamics (CFD) simulations revealed the formation, evolution and dissipation of shock wave patterns during the first millisecond following champagne cork popping. Probably not many, maybe even none.
  - jaywalk 4y ago
    Considering they have actual pictures of the cork popping, it's safe to say that they purchased at least one bottle of champagne.
    - qsi 4y ago
      They seem to have done measurements at different temperatures, so we can nudge the lower bound higher. They also said they used transparent champagne bottles... Did they use Cristal for this? Now I really want to know what happened to the champagne! Although Cristal at 30 C may not be ideal to drink... And what was their budget?
- deleted 4y ago
  [deleted]
bernulli 4y ago
The conditions to reach sonic flow are surprisingly modest! It's fully characterized through the pressure ratio between high-pressure reservoir (here: inside of bottle) and low-pressure surroundings, and a parameter characterizing the molecular structure, the isentropic exponent. For diatomic molecules (our air), the isentropic exponent is 1.4, and the critical pressure ratio at which Mach 1 will be reached is ~0.5, i.e. as long as the high pressure is twice as high as the surrounding pressure, the flow will reach the speed of sound. For more complex molecules the isentropic exponent approaches 1.1, and for steam 1.14, with a critical pressure ratio of ~0.58. I.e. when you release air from a >2 bar (30psi) car/bike tire, you have sonic flow right there!
- cevn 4y ago
  Fascinating... I would like to subscribe to your newsletter!
  - bernulli 4y ago
    Haha, thanks! Let me think about this! ;-)
- robonerd 4y ago
  Unfortunately this seems to be well beyond what the human lungs can do. I found this paper https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1501025/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1501025/ suggesting that the most human lungs can do is about 1 meter of H20, or about a 0.1 bar. So it seems supersonic whistling isn't possible. Oh well.
  - Arrath 4y ago
    I swear my ears beg to differ at the tones some people can reach, ow.
    - h2odragon 4y ago
      supersonic, as in whip crack or jet plane sonic boom, no. ultrasonic, frequencies beyond the range of most human hearing, most certainly yes.
photochemsyn 4y ago
Plausible candidate for an Ig Noble Prize!
knolan 4y ago
Here is a similar visualisation from Phantom using Schlieren: https://youtu.be/kEw2msVaVy0 https://youtu.be/kEw2msVaVy0
julienchastang 4y ago
Related: "Ophthalmologists warn: Flying champagne corks cause serious, blinding eye injuries each year" [0] [0] https://www.sciencedaily.com/releases/2012/12/121217091015.htm https://www.sciencedaily.com/releases/2012/12/121217091015.h...
- Gys 4y ago
  To prove your point, it can happen to the best. This was May 17th: https://www.eurosport.com/cycling/giro-d-italia/2022/biniam-girmay-taken-to-hospital-after-popping-champagne-cork-in-his-eye-after-historic-giro-ditalia-_sto8928697/story.shtml https://www.eurosport.com/cycling/giro-d-italia/2022/biniam-...
  - latchkey 4y ago
    switches vpn to the uk...
71a54xd 4y ago
This is cool, but thank some higher power I decided against getting a masters / PHD. Imagine years of your life dedicated to understanding how a champagne cork explodes. Nightmare material.
- solveit 4y ago
  Clearly you've made the right decision for yourself, but this is unironically the dream for some other people (a very specific type of person, I'll admit, but this type happens to include me and half the HN userbase).
asimpleusecase 4y ago
The end of a whip is supersonic when it “cracks”. It is thought that when towels are “popped” they too can be supersonic at the tip end.
londons_explor2 4y ago
Ooh - Figure 4 of the linked PDF shows temperatures as low as -120 Celcius! And thats from a champagne pressure of just 4 bar. Does that imply that a carefully shaped and designed nozzle, combined with slightly higher pressures, attached to a regular air compressor could be used to make liquid nitrogen?
anti_froid 4y ago
Sounds like Oasis lyrics
aristophenes 4y ago
These are some very smart academics who have figured out how to get their institutions to fund their parties, and probably became very popular in their social circles
bunabhucan 4y ago
https://www.researchsquare.com/article/rs-1273542/v1 https://www.researchsquare.com/article/rs-1273542/v1
anomosmarxist 4y ago

49 points by goatsneez 4y ago

It's amazing how often effects go to supersonic speeds in everyday life. It really makes sense why our hearing is logarithmic, otherwise we'd all be deaf just from a cork popping.

gus_massa 4y ago

The PDF (free, linked in the page) has nice photos of the popping in page 8 and graphics of the simulation in page 11 and 12.

btilly 4y ago

I can't be the only one wondering this... How many bottles of champagne were purchased for this research, and what was done with their contents afterwards?

bombcar 4y ago
> Computational Fluid Dynamics (CFD) simulations revealed the formation, evolution and dissipation of shock wave patterns during the first millisecond following champagne cork popping. Probably not many, maybe even none.
- jaywalk 4y ago
  Considering they have actual pictures of the cork popping, it's safe to say that they purchased at least one bottle of champagne.
  - qsi 4y ago
    They seem to have done measurements at different temperatures, so we can nudge the lower bound higher. They also said they used transparent champagne bottles... Did they use Cristal for this? Now I really want to know what happened to the champagne! Although Cristal at 30 C may not be ideal to drink... And what was their budget?
deleted 4y ago
[deleted]

bernulli 4y ago

The conditions to reach sonic flow are surprisingly modest! It's fully characterized through the pressure ratio between high-pressure reservoir (here: inside of bottle) and low-pressure surroundings, and a parameter characterizing the molecular structure, the isentropic exponent. For diatomic molecules (our air), the isentropic exponent is 1.4, and the critical pressure ratio at which Mach 1 will be reached is ~0.5, i.e. as long as the high pressure is twice as high as the surrounding pressure, the flow will reach the speed of sound. For more complex molecules the isentropic exponent approaches 1.1, and for steam 1.14, with a critical pressure ratio of ~0.58. I.e. when you release air from a >2 bar (30psi) car/bike tire, you have sonic flow right there!

cevn 4y ago
Fascinating... I would like to subscribe to your newsletter!
- bernulli 4y ago
  Haha, thanks! Let me think about this! ;-)
robonerd 4y ago
Unfortunately this seems to be well beyond what the human lungs can do. I found this paper https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1501025/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1501025/ suggesting that the most human lungs can do is about 1 meter of H20, or about a 0.1 bar. So it seems supersonic whistling isn't possible. Oh well.
- Arrath 4y ago
  I swear my ears beg to differ at the tones some people can reach, ow.
  - h2odragon 4y ago
    supersonic, as in whip crack or jet plane sonic boom, no. ultrasonic, frequencies beyond the range of most human hearing, most certainly yes.

photochemsyn 4y ago

Plausible candidate for an Ig Noble Prize!

knolan 4y ago

Here is a similar visualisation from Phantom using Schlieren: https://youtu.be/kEw2msVaVy0 https://youtu.be/kEw2msVaVy0

julienchastang 4y ago

Related: "Ophthalmologists warn: Flying champagne corks cause serious, blinding eye injuries each year" [0] [0] https://www.sciencedaily.com/releases/2012/12/121217091015.htm https://www.sciencedaily.com/releases/2012/12/121217091015.h...

Gys 4y ago
To prove your point, it can happen to the best. This was May 17th: https://www.eurosport.com/cycling/giro-d-italia/2022/biniam-girmay-taken-to-hospital-after-popping-champagne-cork-in-his-eye-after-historic-giro-ditalia-_sto8928697/story.shtml https://www.eurosport.com/cycling/giro-d-italia/2022/biniam-...
- latchkey 4y ago
  switches vpn to the uk...

71a54xd 4y ago

This is cool, but thank some higher power I decided against getting a masters / PHD. Imagine years of your life dedicated to understanding how a champagne cork explodes. Nightmare material.

solveit 4y ago
Clearly you've made the right decision for yourself, but this is unironically the dream for some other people (a very specific type of person, I'll admit, but this type happens to include me and half the HN userbase).

asimpleusecase 4y ago

The end of a whip is supersonic when it “cracks”. It is thought that when towels are “popped” they too can be supersonic at the tip end.

londons_explor2 4y ago

Ooh - Figure 4 of the linked PDF shows temperatures as low as -120 Celcius! And thats from a champagne pressure of just 4 bar. Does that imply that a carefully shaped and designed nozzle, combined with slightly higher pressures, attached to a regular air compressor could be used to make liquid nitrogen?

anti_froid 4y ago

Sounds like Oasis lyrics

aristophenes 4y ago

These are some very smart academics who have figured out how to get their institutions to fund their parties, and probably became very popular in their social circles

bunabhucan 4y ago

https://www.researchsquare.com/article/rs-1273542/v1 https://www.researchsquare.com/article/rs-1273542/v1

anomosmarxist 4y ago