[HN Gopher] Supersonic CO2 flow during champagne cork popping
___________________________________________________________________
Supersonic CO2 flow during champagne cork popping
Author : goatsneez
Score : 45 points
Date : 2022-05-25 12:31 UTC (10 hours ago)
(HTM) web link (aip.scitation.org)
(TXT) w3m dump (aip.scitation.org)
| gus_massa wrote:
| 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 wrote:
| 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?
| [deleted]
| bombcar wrote:
| > 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 wrote:
| Considering they have actual pictures of the cork popping,
| it's safe to say that they purchased at least one bottle of
| champagne.
| qsi wrote:
| 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?
| photochemsyn wrote:
| Plausible candidate for an Ig Noble Prize!
| londons_explor2 wrote:
| 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?
| MichaelZuo wrote:
| 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.
| bunabhucan wrote:
| https://www.researchsquare.com/article/rs-1273542/v1
| anti_froid wrote:
| julienchastang wrote:
| Related: "Ophthalmologists warn: Flying champagne corks cause
| serious, blinding eye injuries each year" [0]
|
| [0]
| https://www.sciencedaily.com/releases/2012/12/121217091015.h...
| Gys wrote:
| To prove your point, it can happen to the best. This was May
| 17th: https://www.eurosport.com/cycling/giro-d-
| italia/2022/biniam-...
| latchkey wrote:
| switches vpn to the uk...
| asimpleusecase wrote:
| 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.
| aristophenes wrote:
| 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
| 71a54xd wrote:
| 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 wrote:
| 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).
| knolan wrote:
| Here is a similar visualisation from Phantom using Schlieren:
|
| https://youtu.be/kEw2msVaVy0
| bernulli wrote:
| 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 wrote:
| Fascinating... I would like to subscribe to your newsletter!
| robonerd wrote:
| 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/
| 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 wrote:
| I swear my ears beg to differ at the tones some people can
| reach, ow.
| h2odragon wrote:
| _super_ sonic, as in whip crack or jet plane sonic boom,
| no.
|
| _ultra_ sonic, frequencies beyond the range of most human
| hearing, most certainly yes.
___________________________________________________________________
(page generated 2022-05-25 23:02 UTC)