Behind the Scenes: Two Vortex Rings Colliding in SLOWMO (4 yrs, 12 hour MEGACUT) Smarter Every Day

Original Video Here: • Two Vortex Rings Colli... High Res Images here:
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We used a computer controlled cylinder to pump fluid behind a rubber membrane to fire toroidal vortices out of the vortex cannons.
We fixed one of the vortex cannon in a stationary position, and used a multi-axis microscope stage to align a second cannon to it… which sounds incredibly easy, until you realize that
DYE density was an experiment all on its own.
If the density of the dye mix was light than water, the vortex would go up.
If the dye was more dense than water the vortex would fall.
We had to overcome SO MANY VARIABLES to overcome and we basically spent about 4 hours figuring each variable.
Water/dye temperature differential
Water turbulence
Water turbidity (cloudiness or haziness of a fluid)
How to reset the aquarium
Cannon Spacing
Cannon Nozzle
Cannon Shape
Dye homogeneity in the vortex itself
The piston displacement volume
The piston stroke speed
Rubber diaphragm tension, would make one side fire faster than the other.
Water or air to drive diaphram?
Firing speed (too slow and they drift, too fast and turbulence tears apart secondaries)
We did a complete redesign of the cannon 3 different times.
The Dye loading method was changed several times
At times We tried to maintain negative pressure on the cannon chamber… we also tried to put shutters on the front of the muzzle. Ultimately I decided it was ok to live with dye dripping out of the front.
We had to premix the dyes and eventually we got there.
It got to the point where we didn’t even really know what success looked like and always thought we were there.
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GET SMARTER SECTION
A Vortex Ring is also called a Toroidal Vortex
en.wikipedia.org/wiki/Vortex_...
Original Research Paper by T. T. Lim & T. B. Nickels (Published in Nature 1992)
202.118.74.190/~elizabeth/Docs/34_Instability_Head-on%20collision_of_large_VR.pdf
Governing Equations of Fluid Mechanics
www.eng.auburn.edu/~tplacek/co...
Numerical Analysis of this phenomena
fluid.itcmp.pwr.wroc.pl/~znmp/...
Interesting Research Papers on Vortex Ring Reconnection
pdfs.semanticscholar.org/3721...
Other Videos created by Dr. T T Lim
me.nus.edu.sg/dept/limtt/video...
Flow Visualization, A Book by Dr. T T Lim
www.amazon.com/Flow-Visualiza...
Why we typically don’t talk about angular momentum in fluids.
physics.stackexchange.com/que...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The thought is my efforts making videos will help educate the world as a whole, and one day generate enough revenue to pay for my kids college education. Until then if you appreciate what you've learned in this video and the effort that went in to it, please SHARE THE VIDEO!
If you REALLY liked it, feel free to pitch a few dollars Smarter Every Day by becoming a Patron.
/ smartereveryday
Warm Regards,
Destin

[@perjohansson8099]

"Spencer R Here is a brief overview it most certainly doesn't cover everything in the 12 hours. Intro: 0:00 Design 2 - College Research Presentation: 1:13 Design 3: Concept Design 6:08 Review of Design 2 with physical model: 10:31 Design 3 - Operation: 27:50 Design 4 - Proposed Changes: 33:15 Relation of apparatus to theory: 46:38 Design 4: 55:54 Design 4 - first operation: 1:14:10 , 1:32:30 Design 4 - New Ideas: 3:33:10 Design 5: 4:20:42 Design 5 - Description, New Diaphragm: 4:53:30 , 4:57:10 Design 5 - First true success: 5:27:23 More Successes: 5:34:00 , 5:36:39 , 6:00:28 , 9:16:50 , 9:30:23 Slow Motion and numerous tests: 6:10:00 - 9:00:00 Theories of how secondary vorticies are produced: 9:32:26 , 10:16:30 Lots of cool Slow-motion: 10:19:18 - 11:46:27 Outro: 11:46:28 Huge thanks to Destin and David Linderman for creating this video, well done" Thank you Spencer R for making this timestamp of the video! He posted it under an other coment, thout It would be nice to have it a bit more vissible!=)

[@regularfries3147]

Thanks, mate.

[@AmazingHD]

thanks, thats what we needed, not a crossword puzzle :D

[@perjohansson8099]

I agree, was so glad When I found it in the coments^^

[@ch890333]

Please make this the top response!! This is helpful!!

[@jimday666]

upvote this timestamp table!!!!!

[@phillipgreenberg6027]

Is it weird to anyone else that in 2018 we don't produce "scientific videos" as opposed to "scientific papers" ? You could actually show the full set up, disassemble it, reassemble it, film tests, and point out interesting items as they occur. Kinda a cross between a how to video, an education video, and a video essay. I feel like you could communicate so much more information than a standard paper.

[@xelnagazchild]

Phillip Greenberg you would still need thepaper first and foremost, associated with the video ; for a lot of reasons related to how scientific knowledge is processed. Plus hosting a scientific video on youtube asks ethics and perenity questions. but such a shape of work (video+paper) would be very good indeed !

[@lucieciepka1031]

If scientific studies were watchable, anyone would have access to that knowledge and we don’t want that to happen!

[@Nick-xc4fy]

I like your thinking. Personally, I would want both, I'd say the paper would be the primary and any video and audio be supporting, but should still be available for people to view.

[@GardenGuy1943]

To do so the video would have to be either super long (like this) or only be made for only certain aspects of methodology. Videos of entire papers would have to be constantly peer reviewed and have a standardized format so it would make sense to anyone watching (just like a paper). Besides, the figures with words should be able to adequately explain it to the same level as a video. There’s a big difference between presenting papers in the form of info-graphic videos (like SciShow) and the day-to-day work by scientists, the main component being the vast amount of terminology / depth that the research has. Making article findings a cartoon and watering down critical thinking for takes away the reality of raw science, so being thorough is paramount. I think it’s a good way to explain ground breaking papers, but not everyone has access to film equipment or editing software (if their paper was ethically okay to film). So not a bad idea, just very limited.

[@sbsftw4232]

Sounds like a great idea as long as you can see and hear. Words can be understood by those without full access to all the senses.

[@alex0589]

...Smarter every day? Try Smarter *all* day

[@MarkyPaligs]

I'd rather Smarter every day, than Smarter all day which is just one day.

[@calvinnorth9642]

Lol he doesn’t get it

[@phosphorus4]

That could be the name of this channel!

[@wangdydu]

Smarter every 3 years

[@got2beable]

haha

[@AnimilesYT]

I thought this was 11 minutes and 47 seconds long...

[@ftbm.]

Animiles same

[@shawnguy3317]

I thought the video was 4 years long

[@marlowkrach6325]

Animiles hahahahaha

[@alot7991]

Animiles hahahah

[@AndyHullMcPenguin]

"I thought this was 11 minutes and 47 seconds long..." It is, but the collisions cause time to dilate ;¬)

[@RobLundgren]

6:23:28 visual & audial acid trip :D

[@rouuuk]

is it rly XD

[@jthm419]

@@rouuuk Played this at .25, no regerts

[@xiaozhai3566]

Hey Destin, I'm not a physics guy but I do research for fluid simulation/modelling in computer graphics. I know such perfect rings colliding is really hard, the closest paper I could ever think of is called Schrödinger's Smoke from Chern et al. I really hope you could release the videos or photo sequences for researchers to access. It'll definitely benefit the computational fluid capturing researches all over the world.

[@wuketuke6601]

i prefer to watch on 0.25 speed

[@awwkaw9996]

0.25? That's beginners numbers, you need to pump those numbers! anything faster than 0.01 is too fast!

[@wuketuke6601]

Awwkaw you're right, we need to watch this on pause

[@jcbalesk777]

@@wuketuke6601 pause? What a bunch of amateurs, reverse is the way to go.

[@brynb-r2528]

Actually like to record it on a phantom v2511 and then watch it back at 100,000 frames a second, some say it takes too long but i feel like it becomes even more amazing when you spend 200 days watching it.

[@jaebassist]

This is precisely why you're a LEGEND.

[@PierceArner]

Best. Megacut. Ever.

[@franklinanderson9687]

My favorite shot of the 12 hours was 11:01:20 The yellow and blue contrasted to the point I could see the vortices change with ease.

[@meowie9136]

thank you, entire 4 years of research down to 12hrs thats saves alot of times, keep me smarter everyday:))

[@graciouscompetentdwarfrabbit]

Got 3rd round of tests next week but who cares. Let's watch 12 hrs of Two Vortex Rings Colliding in SLOW MOTION. LET'S GO!

[@graciouscompetentdwarfrabbit]

If I remember correctly that was before rendering. This video probably has around 24~30GB. I'd say 36GB tops

[@Minib34ts]

One second to just comment on the fact that only 3 years ago the main channel was at 1.5million and since then it has grown over thrice that size. Good work, Destin.

[@schregen]

This took a CRAZY amount of work. Thank you! 💜💚💛💙

[@torvawkkasato6885]

I will say this. I am impressed by how hard this was and how patient you were on this.

[@lacertidaee]

After watching "youtube is changing" video I decided to come back to this one... it's still my favorite. Nothing more special than experiencing the "thought process" in detail and taking us into a journey.

[@charleshanson9467]

It's been really interesting to see how you both came together at the beginning with really different past experience and vocabulary for talking about the objective and describing possible adjustments (to the point of stalling progress at times) but the further we go forward the more aligned your vocabulary gets and the faster the results pile up.

[@MarcLeatham]

Destin. I am beyond FLOORED by you. I need to pursue my dreams like you do. I can't wait to link my first video to you! :) Keep up the inspiration!

[@whalep]

It's great to see the process of research - discussing, theorizing, testing, failures, successes. What an interesting problem and phenomenon! I'm looking forward to watching the rest of this video over some long period of time. Thank you Destin; I'm jealous I'm not working on this problem, but I'm glad you and David are.

[@crohkorthreetoes3821]

Watching Don process the information is just as satisfying to me as seeing the vortex rings. Rare to see a mind like that.

[@postitman]

Watching this in 1-hour chunks or so, because one sitting would be silly talk. Thanks for the inspiration, Dustin! I enjoy watching the process, but I love the infectious passion here.

[@GingerBreadMan1080]

Your channels are awesome and I've gained a whole new respect for masters and artists in their own field.

[@samuelcooley9102]

Wow Destin your work on this succeeds admirable, I look up to you so much not only your intelligence but also the light that shines through from your faith. I wish I had the same type of motivation and persistence that pushes you. Just know your work does not go unnoticed.

[@Butschrick]

Thank you so much for uploading the full video. That was really interesting.

[@yehu41]

Thanks Smart Every Day for showing us the degree of work that goes into all the fancy science and engineering that we see everyday. This is Inspiring.

[@Sideshow19]

I love the process. The results are amazing, but this whole.processes of trying to make it happen are so imteresting to watch.

[@marylagua5079]

Twelve hours appreciate the time you spent making this video.

[@closerb4]

This really shows the process well. Trial and error, scientific method, try and try again; whatever you want to call it, this is a very valuable lesson in persistence, patience, and engaged learning. Thank you for this. I have had to chunk the viewing up, but very nice to watch as a 12-hour mini-series. :-) Thanks guys!

[@louisgillet6222]

Keep doing what you do Destin because it's awesome.

[@marylagua5079]

Will continue tomorrow. Thanks Destin.

[@omerbc]

Destin, you are such an inspiration to all living engineers man!

[@msinaanc]

This puts KZbin into another level man. This is amazing work captured.

[@iamtemo]

Thank you for the mega cut.

[@wobblysauce]

Stumping Don was great and watching him work it out... could almost hear it tick.

[@huidhoofd4886]

Oh my.. I'm gonna have to take a day off to watch this beauty!

[@hvanmegen]

Thanks for this insane amount of content!

[@Onebadterran]

This video is an amazing contribution to science. Thank you for this!

[@nevermore78]

It's nice to see that you had the same type of questions I asked at the main channel, right at 4:52 :)

[@earthtaurus5515]

Going to have set some time aside to watch the entire video otherwise I wouldn't be doing the hardwork you all did justice.

[@SonnyKnutson]

+Smarter Every Day 2 Perfect! Something for me to listen to/watch while I am at home between jobs :D

[@nias2631]

Thank you for posting this

[@zachell1991]

This is literally wonderful!

[@nicolascristi6303]

love you destin! keep it up!

[@unvergebeneid]

4:29:40 Those double rings forming with those asymmetric collisions, with a red layer on the outside and a blue one on the inside, are sooooo pretty!

[@zerge83]

so fascinating, already watched it like 4 times

[@emmanuelbarango4955]

Bro I love your vibe because of you I subscribed I love the persistent talk

[@vazgeraldes]

Vortex ringlets at 90 degrees with the original vortices are formed because of the remaining radial momentum of the flow. As the vorticity of both vortices gets cancelled on each nodule the lower pressure at the interior allows flow from each side of the nodule to its inside (according to the annular/circumferential direction) leading to the cancellation of the flow momentum on the anular/circumferential direction. At this moment the vortical component of the velocity has been cancelled and the annular component of the velocity is also cancelled forming kind of a stagnation point but the flow still contains a residual momentum moving on the radial direction of the plane defined by the colliding vortices. This residual momentum of the flow forms a new vortical structure moving outwards with a plane parallel with the plane of collision of the original vortices.

[@JamesMullaneyUK]

Paulo Geraldes This is a great explanation, basically that low pressure sucks the blobs back into themselves forming two connected semi circles - aka a ring travelling at the angle of the outward momentum

[@zachell1991]

Paulo Geraldes that's the theory I came up with too just not as many scientific words.

[@vazgeraldes]

Referentials in vortices are not x, y, z, the can be twisted according to the vortical component (the swirl) and circunferencial (the low pressure nodule pulling flow from the sides). This seems to be a cancellation of the vortice swirl and circunferencial velocity along with radial component in specific locations but with residual radial velocity at specific locations that forms the 90 deg ringlets.

[@gotindrachenhart]

I can see that the rotation seems to cancel out at the initial plane of impact. And we can see there's little to no mixing going on as the ring spreads out. At first I was curious to see if each mass retained any rotation as the ring spread but it doesn't seem to. Neither do the secondary rings seem to have any rotation.

[@zachell1991]

Gotindrachenhart the secondary rings probably are rotating but not in a way that would mix the blue and red.

[@none4454]

Thank you for posting this. I have be working on this on and off on this too for several years. Several bathtubs of water.... I was using speakers coated with a waterproof coating as the drivers at the back of the tubes. I was also using syringes for the dye. I had mostly gave up with everything sitting on the shelf. I wanted to see non-potato video, and you did it!

[@none4454]

PS: I like sharks.

[@4N5W3R5]

Watching this video... vaping... making vortex rings :) Cool stuff!

[@mellonsb]

13 weeks, I'm 1/2 way through it. Watching it here and there, but I will watch the whole thing out of fascination.

[@MykelSturgill]

Destin... Man... I've been waiting along time for this... I knew you would come along.. Ohh man, thank you for your perseverance, just like riding that elcyciB. Wow. All your virtual gardening for that deliciois piece of visually scruptious morsle at 11h19m30s. Wow. And all the rest. Understanding, forming. Wow. Also, for others, while trying to find the most primo shots using mobile KZbin and not being able to easily scroll thru the time bar I learned you can double/triple/tap/tap/tap the beginning and ending timestamps on the time bar in order to rewind and fast forward incrementally. I would have never known this without trying to click/drag/click/drag that little red ball across the screen with my thumb, pixel by pixel. The agony! The ecstasy!

[@lknight8854]

Im gona have this on in the background while I build my i3 mk2 kit

[@codefeenix]

No way ill end up watching it all, but thanks for uploading this! through 45 minutes @ 1.25x and enjoying the conversations. Sometimes the road traveled is the most interesting part!

[@neodos]

Wonderful! thanks for all your work and sharing it. Now I wonder what it would look like if you did it vertically.

[@dopaminDavid]

really inspiring with beautiful music

[@bulldozer7656]

Wow, your experiment is so cool... Just to figure out what's happening makes my brain hurt, lol. Excellent work and project!!

[@SilvaPlumbingServicePtyLtdCanb]

it forms smaller ones at 90 degrees because the two vortexes of opposing rotation form a figure 8 and invert on themselves (think two slinkies in contact as an oval then changing hands and inverting. This inversion is what causes the vortexes to change plane of motion (also lower energy state of motion to rotate in a doughnut form away from origin. note no colour mixing untill well after small secondary vortexes form. Rotation starts at primary vortexes, low pressure zones are on outside of each vortex. never mix, low pressure zones invert with highpressure zone to cause inner rotation equidistant small vortex. ( im sure you already figured this out two years in... if not, a name drop would be awesome)

[@Broxine]

Thats the most interesting video i saw in years

[@gscapinelli9214]

I do not have a Twitter account, so, (shark here). It is awesome you released this one, that was really a hard feat! It is nice that you choose David to work with you, he seems to be an awesome guy just like you! This is a 12 hour behind the scenes video that is not boring to watch. Congrats to you two on everything!

[@paulcarr1764]

Thank you so much for publishing this. I'm only an hour in, but I love the discovery and trial and error.

[@paulcarr1764]

No shark tweets from me.

[@paulcarr1764]

Not sure if this was intentional or not, but you have some video overlap at 10:35:30

[@paulcarr1764]

Just finished. Really worth my time. I hope you do more research paper level stuff on the channel.

[@CarminaEnoctis]

Well I don't tweet so I couldn't send a shark to say I'm watching the whole thing, but I did! (Ok, I didn't pause every time I left the room, and occasionally came back and wondered why the video had frozen during one of the super-slow playbacks!) I appreciate your showing a sampling of the work that went into it--people so often see only the finished project--be it the youtube final edit or the published paper--without appreciating how many hours, iterations, blood, sweat, and tears went into producing it! If there is one thing I learned in grad school it is that good science is often very tedious.

[@Readyplayer11]

Wacthed till the end

[@shreyasp3287]

The puzzle was really geeky I love this

[@willson8686]

OH MY Goodness , you dont know what you created !!! thanks for the inspiration...

[@exequiel_israel4844]

This man a legend

[@slendeer_games8731]

11:17:24 Is a nice shot for those wanting to see just the rings collide

[@fearstreak7462]

8:00:20 hey Vsauce, michael here. memes aside, this is what got me into engineering, working with my best friend after school hours in the lab working out the kinks in our latest assignment. we'd stay over for hours but we'd never complain because it was our passion to work on it until we got it right. i can see that passion as you worked on this and i want to say thank you for reminding me why im continuing to study and what i want to put into my future work.

[@TWCHHK]

Destin, vortices are very important in aviation as well. We deal with them all the time and they basically show how the wings can generate lift. I'm trying to find out if there is away to explain the phenomenon you're showing here with aerodynamics. Air is a fluid as well and should act like an incompressible fluid up to much greater speeds than for your experiment. Really fascinating phenomenon!

[@saqibmudabbar]

Hey Destin, I think when it’s rotating “the filament” it’s not just rotating, if you watch closely it’s leaving behind the fluid that rotates over it to form the center and when it’s about to reach it’s limit the residue in the middle becomes thicker, if you see that happening from an angle parallel to the expansion, you’ll see a cavity/hole in the middle of the spheres that form before the rings. That happens exactly when the rotating filament leaves behind it’s residue in the middle. These spheres since they still have outward momentum flatten out and since they were rotating, they give an illusion of rotating 90degrees. That’s what I think happens. I’m a cardiovascular doctor so it’s not really my expertise to talk on fluid dynamics but I hope this helps. I’m sure you already know this by now. Really amazing footage. Well done!

[@jezzamanu2960]

marathon here we come, imma try to do this in one sitting

[@TheJoHeWe]

I have been watching this video for 5 and a half hours. Although I won't be able to feel the same way as two years of effort with this result, but I can understand very well why you want this to stay in video format and no one making it in a gif.

[@BenjaminDamoncycle]

You can't get any more southern in fluid dynamics than comparing it to mixing of 'sweet and unsweet tea'.

[@aianyoung]

12 hours! Wow. Time to make some popcorn.

[@laureven]

You asked to watch this I the background ...I'm trying to do something but I'm able only to focus on this. super interesting

[@brutalteam3795]

even more MAD RESPECT!

[@rodrigoff7456]

WOW 4:57:11 though it was not the goal, there are some secondary rings right after the blue vortex "eats" the red (4:57:17)! really nice and impressive!

[@bryantribolet]

Awesome! Keep up the interesting work. I'd think it would be easier to achieve regular toroids with a common fluid density. The dyed fluids have a greater density that's why they are always leaking out of the cylinders. Once this begins to happen the dyed fluid in one cylinder may have more water intrusion than the other which creates a dissimilarity between the relative densities of the toroids. This in turn causes one to sink more rapidly than the other and the result is that they may not meet well. By adding salt to the tank it should be possible to create a solution density equilibrium and thus better stabilize the fluid medium for the toroids to collide within as well as mitigate density irregularities between cylinders from intrusion of the medium fluid.

[@Twee877]

These colors look beautiful I think I can do all 12 hours

[@cropsey7]

that was awesome

[@OtherTheDave]

I fully intend to eventually watch all of this, but I may need break it into a few sittings.

[@MrGustavier]

hey Destin, I've been a great fan of you for several years, I love your content, you're the best ! I think people and yourself have a good idea to why the secondary vortices form, result of an instability. but I haven't read anything to why the instability appears in the first place. I have a suggestion, is it possible that it is an interference pattern ? after all, you have two sources at the beggining, and the smallest difference between the centers of the two initial vortices would create an interference pattern, that would take over as soon as the radius of the first expanding vortex becomes too thin. that would explain the fact that they appear so regularly spaced, and it would also mean that the real perfect collision would prevent the formation of the secondary vortices. what are your thoughts ?

[@1LEgGOdt]

Okay I'm going to save this for the 4th of July week

[@bertpasquale5616]

Hey Destin, love this! Can't help but to see the artistic potential here. Would you try this: Put in a single piece of white plastic that covers the bottom and back with a medium curve - this will create a "seamless" backdrop. Then, increase your lighting using strobes and take still photos at about 10 fps. Try more backlighting on the vortices. if you can balance out the background and ink, this could be GORGEOUS!

[@cyberbeefpv2810]

Thanks!

[@agmessier]

I've been thinking about this off and on throughout the day and have what I think is a plausible explanation. I haven't read any papers or looked at any other explanations so forgive me if I'm rehashing what you or others may have already figured out. As each vortex ring propagates, the fluid in the center of the ring is flowing at twice the rate of propagation of the ring, and there is energy associated with this velocity. When the two rings collide, the flow meets a barrier. Because of the principle of continuity, the flow turns outward in a radial direction. Because of this, the nature of the vortices changes. They are no longer two ring vortices with flow through the center. Rather, they are a counter-rotating pair of vortices that form a closed loop, with the fluid flowing between them as they go radially outward. Now my background is in aerospace engineering, and when we learn about flow separation over a wing, it occurs when the flow is slowing down as it traverses a positive pressure gradient toward the trailing edge. Similarly, as the rings are expanding outward, the vortex filaments are elongated due to the larger circumference. They get weaker and lose energy. This accelerates an instability not unlike the crow instability seen in aircraft contrails. The vortices pinch together and reattach forming smaller ring vortices. They are oriented outward because that's the direction in which the original vortex filaments were moving. Once they form separate rings, they can propagate without being stretched, so they are more stable.

[@vojtechjanku2534]

12 hours is so much, could you maybe make a list of timestamps for a general orientation?

[@spencerr505]

Here is a brief overview it most certainly doesn't cover everything in the 12 hours. Intro: 0:00 Design 2 - College Research Presentation: 1:13 Design 3: Concept Design 6:08 Review of Design 2 with physical model: 10:31 Design 3 - Operation: 27:50 Design 4 - Proposed Changes: 33:15 Relation of apparatus to theory: 46:38 Design 4: 55:54 Design 4 - first operation: 1:14:10 , 1:32:30 Design 4 - New Ideas: 3:33:10 Design 5: 4:20:42 Design 5 - Description, New Diaphragm: 4:53:30 , 4:57:10 Design 5 - First true success: 5:27:23 More Successes: 5:34:00 , 5:36:39 , 6:00:28 , 9:16:50 , 9:30:23 Slow Motion and numerous tests: 6:10:00 - 9:00:00 Theories of how secondary vorticies are produced: 9:32:26 , 10:16:30 Lots of cool Slow-motion: 10:19:18 - 11:46:27 Outro: 11:46:28 Huge thanks to Destin and David Linderman for creating this video, well done.

[@vojtechjanku2534]

Spencer R I love you

[@FirstLast-fu8qz]

you're a legend Spencer R

[@MykelSturgill]

Spencer R Amazing. I just spent the last hour an a half looking for the best looking shots. Now I find your guide. Lol. 11h16m is the best I've seen so far, in my humble opinion. 10h5m is also excellent.

[@tim5965]

11:19:28 is also very good

[@chicohaze787]

Must've watch a thousand times

[@nicolasflamel8969]

Thank you for your hard work and perseverance. So you have not yet found a reason for the formation of secondary vortices or their number and orientation? It's fascinating.

[@Kanisterschaedel]

11:01:18 is one of the more beautiful results. Love it!

[@salimufari]

@Destin I was watching at 10:18:00 and you said exactly what I was thinking. Angular momentum forcing the low and high pressure points in the outer ring to create it's own independent vortex. The conserved wave force from the ring and the fact that a wave's force will pass through or around another object would make the pressure vacuum turn into another expanding ring as the wave passes through itself at center. Just spitballin' here though ^_^

[@pocholo151299]

Salimufari thats what I first tought. I didnt study fluids mechanics yet (I am in 1) but i found it pretty intuitive. My question is, why does those noodles form? They are pretty regular (Sorry for my english, it isnt my first language)

[@salimufari]

Also not a master in fluid dynamics here either but I do know that waves in a fluid or gas will continue to move around or almost through solids. What this implies is after the initial collision of both inks their forces should pass through each other and continue past. This creates turbulence as some of the fluid (being not compressible) interacts as they spread. I'm not sure if the ink being a different density than the water has an effect but I don't see how it couldn't. Water and ink viscosity being major factors here. Like smoke rings in air the halo happens when the ink swirls in this turbulence. With smoke the ring is formed by a low pressure pocket in the middle and a pressurized ring on the outside. Here the pressure of the collision makes a similar event and the low and high pressures have a direction of their own.The smaller ringlets are caused by a symmetrical collision. As the ring expands it leaves a low pressure in its wake. This is also why this took so long to get on camera. All conditions had to be perfect. Ejection speed, mass, inertia, aim, distortion after being "fired" just to name a very few variables. In all of the 'miss-fires' you can see how they pass by or around one another not giving the desired look. I know there is more going on here that I don't understand but this should cover most of the known things. Good luck on the finer details.

[@SeanMohundro]

I got super excited, I thought this was going to be 12hrs of the vortex blasts...

[@CorporateZombi]

Fluid dynamics was not my strong point at university but it looks a bit like, when the rings collide (6:06:20), they expand in two rings that are in super-critical (fast smooth lamina) flow (6:06:45). As the two rings expand, energy is lost, and at points around the circle the rings become sub-critical (6:07:23), the rotation in the two expanding rings then break like a wave in a hydraulic jump (6:07:43) and expands out of the plane of the rings at the sub critical points. This causes the expanded rings to instantly slow. Further super-critical flow then fills behind the slowed expanded points in the low pressure wake, and blows through the wider wave (6:08:39) forming the secondary smoke rings (6:11:19)

[@Gusto20000]

The front of the wave experiences viscous tension of clear water going through it, and when it gets too thin (circumference is 2*pi*Radius, so roughly it grows 6 times the radius) it breaks at weakest points. Then it gathers into a blobs and since every blob still has momentum, starts to behave like the fluid shot out the nozzle initially.

[@zachell1991]

That's what I was thinking

[@alaboutfood2326]

so basically in the simplest terms... u got ur chocolate in their peanut butter. Cool, whew!!! saved me 11hrs 58mins. Just Joking!!!

[@NathanielStickley]

I see that you have already posted a link to an article that basically explains this (entitled "Reconnection of Colliding Vortex Rings"). It would have been cool if the main video mentioned this. It would be SUPER cool if you had a video, some day, on magnetic reconnection, which is a similar phenomenon; there's a pretty strong analogy between vorticity and magnetic fields (which makes sense because the vorticity field and the magnetic field are both are the curl of a vector field).

[@texhorn99]

Yeah im about to watch this whole thing. Maybe ill learn something

[@franklinanderson9687]

I don't tweet, but *"SHARK"* WHOOYAAH!

[@staizer]

So, what I think is happening: This isn't just two wave fronts colliding, it's two wave fronts colliding with a stationary front. If you watch some of the footage in the middle, you can see a cushion of colorless water getting compressed by the red and blue water. As the fronts expand they take this cushion with them. You can see not only concentric waves as the fronts expand, but also radial waves. As a result, this forms cone shaped "still water" that is getting forced in the direction of the expansion. At some point, the compression wave forces the colorless water out of the ring of colored water in a direction orthogonal to the original colored waves. These act like radial jets squirting colorless water through the colored water, creating a circular perturbation that changes the direction of those rings.

[@useazebra]

Can you imagine being the video editor asked to work on this? "Yeah, I have 12 hours of footage. Need you to cut it down to like 4 minutes. K thanks bye."

[@tl4ever262]

This is one experiment that needs to be done on the space station.

[@SkylersRants]

7:51 is amazing!

[@nightcrawler1335]

I think I'm the only one to watch this video from start to finish fully without any skipping. Nearly 12 hour straight.