More Kelvin-Helmholtz (The Experiment) - Sixty Symbols

[@sixtysymbols]

This is a second video, made public a few hours later, which just details the demo apparatus... If it appears in your feed AND you have already watched it, that is because you are good and loyal Sixty Symbols viewer who clicked the links on the main video. MAIN VIDEO: kzbin.info/www/bejne/p5jEnpmlbZt5h9E

[@AngryLizard0]

What would the instability look like if there were three fluids? one traveling up, one traveling down and the third being stationary. Would the instability take effect on both sides, like a mirror?

[@a006delta]

The_Blu_Nova I think so too. Mainly because fluids just need to move *relativly* to eachother.

[@Majromax]

It depends on the layer thicknesses and relative densities. If the layers are very thick, it will look a lot like two separate sets of instabilities that may or may not be in-phase. If the layers are very thin, then it will be easier for the layers to 'roll up' together. This is then modified by the relative densities. One thing not mentioned in the main Sixty Symbols video is that when the fluids have different densities (like fresh and salt water), the force of gravity acts to stabilize things -- the heavy fluid that gets pulled up by the pressure has to fight against gravity to get there. If the three layers have very different relative densities, it might be possible for the Kelvin-Helmholtz billows to grow at just one of the interfaces.

[@NoActuallyGo-KCUF-Yourself]

I watch all the Sixty Symbols vids, but this one doesn't show up until 5 years later?!

[@bloo777]

At 4:33 it looks like each wave gets it's own instability waves on top, so the whole setup quickly becomes a fractal for a second or two until the turbulence fully kicks in and mixes it all up. Amazing setup! Well done and thumbs up for dr Turnbull!

[@LordBax]

Yes! I thought this was the most amazing part. I wonder if the students are using fractal mathematics to describe this.

[@kalleguld]

The delay between tipping the container and the instability showing up is awesome. You can really see it's a self-amplifying effect. I thought you had paused the video at first.

[@Hippo_Heli]

Wouldn't it be easier to use oil and water?

[@valeriobertoncello1809]

SPKY 13 Interesting question... I think the answer could be the need for two liquids of different densities but same viscosity.

[@vishnuprasadps2243]

Water and kerosene? Approximately the same viscosity, if my observation (at home, so maybe wrong) is not wrong. Also, saves the trouble of colouring the liquid!

[@Les537]

Pah, water. You could simplify this set up even more with some dynamite and plutonium.

[@deantoth]

@@Hippo_Heli no, because once you are finished you then have gallons and gallons of oil that you have to dispose of. Rather than some vegetable colored water. Multiply this by how many students run the experiment during a lab.

[@IstasPumaNevada]

Fascinating how quickly and uniformly they pop up.

[@elsydeon666]

I love how this experiment is capable of being done in a primary school environment. A 3rd-4th grade teacher can easily (well, it does require some prep) do this, and it's less messy than the infamous volcano.

[@vishnuprasadps2243]

At 3:39, we see the first instability occurring but within a couple of seconds we can observe a second instability occurring on top of the first "seahorse-head" for a fraction of a second as the process repeats itself. Absolutely beautiful. Correct me if I am wrong.

[@GlazeAndMaren]

Great video and experiment, Brady and the team!

[@sixtysymbols]

+Rasmus thank you

[@dermotmclaughlin9960]

If the dimensions and angle of tilt of the apparatus were changed and optimised for visual effect could this experiment be designed with chemicals which would naturally separate afterwards or is mixing an inherent property of Kelvin-Heimholtz waves

[@ognog3489]

Wow... what a cool experiment. Thank you for taking the time to make this and share with everyone :) There look to be more going on in this, I'd love an explanation on the lag before the hooks form.

[@longalexislong]

at 3:41 it looks like you can actually see some second order instabilities on the boundary of the first vortex like instability! Neat

[@StreuB1]

Fluid dynamics come front stage. Awesome!

[@nab-rk4ob]

Thanks for helping me understand how clouds and air pressures work just a bit.

[@am2schmarvelous]

You can see little horse heads on top of the big horsehead just before they become too mixed to wave anymore. Is Mandelbrodt inside the Kelvin-Helmholtz?

[@valeriobertoncello1809]

I noticed that too!

[@zenodorous]

itsathought2 There is definitely some kind of fractal-ness to it!

[@JackFlead]

Maby a silly question, would the effect work with the same set up but with oil and water? might result in an experiment you could repeat a little easier.

[@LeoWattenberg]

it even works with air and water, that's why we have ocean waves :) But if you use vastly different densities (freshwater is 1.00g/cm³, the saltwater here is 1.01g/cm³, sunflower oil is 0.92 g/cm³ - that's 8 times as much of a difference), the effect becomes less clear. Again, this is the reason why ocean waves look like they look instead of something more Kelvin-Heimholtz-y.

[@planetsoccer99]

Why does it become less apparent? You'd think a greater dp/dz would give a higher BV frequency, no?

[@LeoWattenberg]

Since the density here is so close, you get almost symmetrical patterns, which is what makes this so beautiful and special in a way. If you use very different densities, the symmetry goes away and it also becomes chaotic much more quickly _[citation needed]_.

[@xja85mac]

It seems a silly question at first, but now I want to see it. Too bad I don't have a plexiglas tube to do it myself...

[@valeriobertoncello1809]

Maybe the different viscosities of oil and water make the experiment harder to do.

[@TheyCallMeNewb]

This was a thing of such indescribable beauty

[@stormbril]

The music is fantastic! I've looked through Alan Stewarts stuff however, and I can't find the exact song. Anyone know it?

[@deantoth]

Agree. Same question.

[@minichiggz]

I'm feeling nostalgic because this was an important concept for my undergrad research!

[@sylak2112]

This is so simple but so gracious and fascinating. Damn Physic is cool.

[@Corvaire]

You've just created a perfect visual analogy for the zero dimension! ;O)- Unlike our own dimension, the trans-dimension has little to no pressure (do it's extension from Real Time,) so when quantum frequencies glide across in zero (neutral time/space) dimension they cause a multitude of various reactions (which we call _particle waves_.) - of course science hasn't caught up to this synopsis but I'm hopeful we are just around the corner as we dive deeper into gravity waves. - Corvaire ;O)-

[@andrin4871]

after the third camera angel i was like and where is the slow motion? wasn't disappointed

[@Melomathics]

Great music, Alan.

[@nathanhastings8293]

I would like to hear more about the nature of the vorticity of the Hemholtz cinnanan roll and how it shifts in a predictable mode (like the processing of a gyroscope about an axis.

[@markschweter6371]

What happens if you change the tank's dimensions? a) Keep the tank the same height and double or half the width? b) Keep the tank width the same and half or double the height? c) Try longer/shorter tanks? What happens as you gradually increase the density difference between fluids?

[@ayushranjan6807]

Any videos coming up featuring Prof Phil Moriarty? Love his videos

[@Firecul]

Got to love that permanganate staining. Always wear gloves or only use a very dilute amount. It's not that toxic but you get left with purple hands for a long time.

[@xja85mac]

A close-up of tank two would make a great desktop background.

[@petrantobaccopipes]

2nd law of thermodynamics visualized. Beautiful effect!

[@carom1]

This kind of reminds me of the bands Jupiter, how they mix and swirl where they contact each other. That's pretty cool.

[@masterimbecile]

I remember seeing a demo before with a spinning acrylic sphere filled with what must have been many layers of blue liquids of different densities and polarities (e.g. oil and water). At first I didn't get the point of it, but I think I do now: we were supposed to spin it (and maybe even stop it) so the layers of liquids would move pass each other to create this effect.

[@honkatatonka]

So beautiful. Thanks for the hard work you are putting into that. And of course to the people doing those experiments!

[@NoActuallyGo-KCUF-Yourself]

Mmm, satisfying laminar to turbulent transition. I remember playing with those toys in my hydraulics class.

[@jesutherland]

LOL the music is awesome!

[@AM-ui9mc]

Awesome track! What's that song?

[@peterluxus7382]

It looks like the clouds patterns of Jupiter!

[@yaoooy]

the same phenomenon occurres in Jupiter

[@medieval2]

Love the soundtrack to this video. Where can I get a copy of the soundtrack?

[@SirDominic]

So much prep work for such a quick experiment. Fantastic imagery though!

[@levihenze9297]

Is there a repeatable version for the mixtures? I guess It works so beautifully because of the very similar densities of salt water and fresh water. And a oil/water mixture or something like that just has a much too big density gradient to observe it.

[@IllidanS4]

"Look how impressed these guys are." Exactly.

[@derradfahrer5029]

Does anyone have a clue, what factor contribute to the wavelength of the vortexes. My guesses are the speed difference between the to layers and maybe the (average) density of the fluids.

[@bobcargill4506]

The wavelength does appear to be similar for the two demonstrations. Perhaps related to the speed of sound in the media and a standing wave in the two flows? Interesting question.

[@BillyNitro]

I wonder what they look like from the top? The tallest part of the 'wave' appears to be pressed against the far side of the glass. Are they making sequential small whirlpools?

[@TimBowers]

Lovely footage for HI!!!

[@Gameboygenius]

What determines the size of the waves? Can the size be reliably controlled by controlling the densities of the liquids, certain dimensions of the container or other parameters?

[@fsmvda]

What is the wavelength of those bumps? It looks like a wave from the water hitting the bottom end of the pipe propagates upwards and gets amplified. If they went back and measured the length of that clamp it could be compared with the wave in the video to get the wavelength.

[@psteknyo]

This is cool. I'd like to see the experiment repeated with two insoluble liquids, in hopes to better see the vortices without the colours mixing.

[@MrRobinhalligan]

So how long did it take to get set up from adding the salt water to ready to go?

[@Cotonetefilmmaker]

very cool, you can see the moment in which the whole thing becomes turbulent.

[@MephistoRolling]

I assume the frequency/spacing of the wave shapes is based on the ratio and speed of the different liquids or gases?

[@wongwanchap]

I understand why the disturbance are magnified. But why the disturbance seems occur in an almost equal distance distribution? One explanation maybe the disturbance is caused by some sort of small standing wave.

[@UberAlphaSirus]

Heimholtz Resonator, bass port in speakers, same fella right? Fluid dynamics?

[@kupalan4374]

I wonder what does this effect look like when viewed from above?

[@SapientPearwood]

ok tbf we fluid dynamicists can be a bit blase about these basic fluid dynamic instabilities, but they really are very beautiful

[@AttilaAsztalos]

Needs some fine glitter mixed in both liquids so that local movement can be more readily followed on the slow footage...

[@Mozto]

I'm intrested to buid one of these to my Fludic Mechanics students. Is there any link of this project with some of the design considerations ?

[@paolotorres763]

Could anybody tell me how's this applied/taken into account in engineering projects?

[@planecrazy2]

It is interesting when it goes from laminar to turbulent and how much better it mixes when turbulent.

[@beachboardfan9544]

Probably some micro organisms in there that got the best waves of their lives

[@Henska]

Would it be possible to do the experiment with more than two liquids?

[@valeriobertoncello1809]

I'd assume it would!

[@JM-us3fr]

Now now children, let's not break the universe

[@ekarademir]

That's what's happening in Jupiter.

[@clasherspoint8897]

How much cost will be for this apparatus

[@manfredpseudowengorz]

4:36 it looks like there's another layer of this effect on top of the biggest waves, i guess this pattern repeats itself in different scales which eventualy causes the perturbations and collaps to a complete mess. am i rite?

[@kevyelyod1211]

Would the same effect happen with oil and water?

[@sirkowski]

Groovy.

[@oliverracz8092]

who is the older guy walking in? looks like Ferenc Csagoly

[@AvanaVana]

Use a white backdrop next time

[@farzaan1479]

What's the reason for the delay?

[@SJohnTrombley]

Why not use something that isn't miscible with water (mineral oil maybe?) to remove the issue of the layers mixing?

[@aarcaneorg]

Why not use something like Oil and Water that will mix then separate again afterward so you can repeat the experiment after allowing it to settle out?

[@mho22]

I think the density difference between oil and water is to huge. But I am quite sure it would work with a polar/unpolar setup, you just need to find or make them with small density differences.

[@dragoncurveenthusiast]

It also works with air and water (ocean waves), and oil is definitely denser than air, so I'd speculate that it would work. but maybe the effect is not that nice (for some reason I can't think of) or there are some practical disadvantages like cleaning the tube from salt vs oil residues

[@deantoth]

Because storing a 200 pound oil filled tube all year only to haul it out once or twice for this experiment is far more trouble than just filling it with simple disposable, safe cheap water.

[@paulbriggs3072]

This same process applied to geology has proved the theories wrong that mud and clay settle very slowly over time in water environments. The Kelvin-Helmholtz turbulence in fast moving waters such as floods when encountering a different layer such as cleaner water, produces fast sediment sorting into different fine-to coarse particles and rapidly increases deposition. Now it is known that vast mudstone and siltstone layers of significant depth can form quickly and with fine layered sorting during catastrophic flooding.

[@jake_a_g]

I'm missing that sexy Sixty Symbols watermark.

[@damienw4958]

KZbin! Why you no tell me about sixty symbols videos!

[@sixtysymbols]

This one is still unlisted - I make it live a bit after the main video so that most people don't see it BEFORE the video that is supposed to come before, but I make it watchable so people don't have to wait....

[@damienw4958]

Sixty Symbols ok thanks!

[@ArneSchmitz]

Sixty Symbols i watched it before. Saw it on twitter first.

[@ognog3489]

Does anyone else see the mini-hooks on the greater hooks at 4:40 ?

[@austinnguyen9107]

0:28 half full / empty?? It depends on whether u are filling or emptying! Try it out for yourself. : )

[@Squidward1314]

Why is it happening everywhere (along the interface) at the same time?

[@Subbestionix]

niceeeeee!!!

[@clasherspoint8897]

On what principal it works ???

[@fuadjemal]

how long did it take

[@gottalikeit2010]

wow. glad i smoked one before watching this.

[@RUBBER_BULLET]

Who half-fills a container from empty and then describes it as half-empty?

[@NoActuallyGo-KCUF-Yourself]

Exactly! Half-empty vs half-full is about direction of flow rate.

[@amidhmi5243]

This is my lab! I work here!! :)

[@amidhmi5243]

In pounds Sterling... Monthly...

[@astromus]

"...pumping the tanks half (...) empty (...) with fresh water" - hmm... ;-)

[@SirCutRy]

Human music? I like it.

[@backwashjoe7864]

I get that reference!

[@mennoduk]

Why don't you use oil and water so it can be done more than ones?

[@deantoth]

Because dealing with gallons and gallons and gallons of oil in a giant 100 pound tube of liquid is a huge amount of hassle. Disposal, leaks, storage. And anyway the educational value of setting up the experiment is also worth something. Just walking up to a tube that's already filled and just tipping it is far less educational.

[@jiaming5269]

is this related to turbulence?

[@valeriobertoncello1809]

Is math related to science? - Katy Perry 2017

[@seanehle8323]

Turbulent flow is mixing flow, which you can easily identify in this video once you know what to look for. The parts where the liquid stays its original color are experiencing laminar flow (non-mixing flow). The parts where the color changes to a new, perviously not-present color is where the mixing flow (turbulent flow) is happening.

[@hiqwertyhi]

the background music sounds like runescape

[@free_spirit1]

Next time put a white sheet behind it!

[@RobouVideos]

you only had one job : putting a white screen behind it so we can watch the experiment correctly. :)

[@williambaker7181]

Sixty Symbols can you ask your scientists whether or not they believe in free will?

[@bruenor82]

the horse heads have mini horse heads

[@joshuaheise7615]

would've been 10x better if you had just taken the time to put up a white background.

[@Puleczech]

Exactly. Sometimes these things seem just too lazy. Don't get me wrong, I love it, but put 15 more minutes of effort and it will come out waaay better.

[@JohnnyMotel99]

or a black background with strategic lighting, at least for the two colour version.

[@AttilaAsztalos]

Probably blew all the budget on salt and colorants... :P

[@mistag3860]

Its no wonder we are pattern seeking mammals.

[@barrymckokiner5078]

Why didn't you tell people why it happened rather than just that it in fact did?

[@PaulPaulPaulson]

If we can watch this on earth, why did we send a probe to Jupiter? 😉

[@robertolson7304]

9/11 floors all gave out at once.. what ever resistances was left wish what we saw on tv