When Vortex Rings Collide

Intrigued by a grainy video from 1992, [Destin] from Smarter Every Day decided to jump in and fund his own research into the strange phenomenon of vortex ring collisions.

This hack started with a scientific publication and a video from back in 1992. The paper, written by Dr. T T Lim and TB Nichols, illustrated what happens when two vortex rings collide perfectly head-on. The rings collide and spread out forming a thin membrane. Then smaller rings form at a 90-degree angle to the original collision. It’s a beautiful effect when created with multicolored dye in water. But what causes it? There are theories about the fluid mechanics involved, but not much research has gone on since Dr. Lim’s paper.

[Destin] wanted to find out more about the effect, and get some video of it. Being the guy behind Smarter Every Day, he had the high-speed photography equipment and the funds to make that happen. Little did he know that this passion project would take four years to complete.

The initial prototype was built as part of a senior design project by a group of college students. While they did show the phenomenon, it was only barely visible, and not easily repeatable. [Destin] then got an engineer to design and build the experiment apparatus with him. It took numerous prototypes and changes, and years of development.

The final “vortex cannons” are driven by a computer controlled pneumatic cylinder which ensures both cannons get a perfect pulse of air. The air pushes a membrane which moves the dye and water out through an orifice. It’s a very finicky process, but when everything goes right, the result is a perfect collision. Just as in Dr. Lim’s video, the vortexes crash into each other, then form a ring on smaller vortexes.

Destin didn’t stop there. He’s made his data public, in the form of high-speed video – nearly 12 hours worth when played at normal speed. The hope is that researchers and engineers will now have enough information to better understand this phenomenon.

You can check out the videos after the break. If you’re a Smarter Every Day fan, we’ve covered [Destin’s] work in the past, including his backwards brain bike and his work with magnets.

34 thoughts on “When Vortex Rings Collide

  1. Great persistence, great results and great presentation!

    And I like the random bit “and here’s Astronaut Don Pettit, giving some ideas” ;)
    If anyone actually goes through the 12 hour megacut, is there more footage with Don?

    Also, is there a search function for YouTube comments?

    1. How should that be possible? There is no gas that can create these vortex rings. And even if you put a vortex cannon into space (which exhausts a stream of gas), the rings will have nothing to push against and soon will vanish.

      1. You could have a vortex ring in space if you use gravitational forces to replace the cohesive forces of liquids. There is no reason you can’t have a ring of material in space rotating about the axis of the ring with the gravitational mass of the ring preventing the material from leaving. It would not be stable forever, but neither are vortex rings suspended in liquids and gases.

          1. If our universe is a vortex ring? Then perhaps it is in the process of a collision with another vortex universe. Explaining why it is expanding increasingly faster? It appears that during the collision and formation of the disk membrane, acceleration occurs to the point of the formation of the minor vortex’s. As both rings have approximately the same forward momentum at the collision point, the energy can only be transferred outward. For lack of knowledge, I will say this energy is then combined with the swirl in the rings, angular momentum? This additional energy peaks and forming the minor rings and spending the last of this energy against the buoyancy of the fluid? I am not a scientist, mathematician nor an engineer. Please don’t beat me up if this is a ridiculous thought.

    2. You’d have to operate at a whole different scale (orders of magnitude different). Others are saying space is a vacuum, but of course that’s not true. It’s full of stars, planets, and nebulae. We just don’t have a way to push these around, though. Space also contains “lots” of hydrogen atoms and whatnot, but at very low densities compared to anything earthly.

      1. Space is indeed a vacuum.
        There are different definitions, or grades of vacuum if you prefer, based on particles per volume ranging from 100’s per mL to zero point energy fields.
        As far as vortices I think @deralchemist is correct. If you succeed in creating a vacuum using an artillery piece or vortex canon, the ring will quickly dissipate once it enters the vacuum. You need friction between the two fluids in order to propagate the vortex, without it the ring will scatter according to the momentum of each particle.

  2. Would something like this explain some instances of colliding gas clouds forming stars?
    Or on a larger scale could it explain the distribution of galaxies and/or galaxy clusters in the universe?

  3. There is plenty of evidence, just most people choose to ignore it (and its existence) because they don’t want to acknowledge God.

    Instead, they invent theories so that they can try to explain things while leaving Him out of the picture. They have no evidence to suggest what they say, but they say it anyway. They call it science, but turn around and say that they will ignore any evidence they’re wrong. And by and large, people believe them – with no evidence whatsoever. In fact, there is a huge amount of evidence that they’re totally wrong, so it would be more correct to say people believe them despite evidence. All so that they can try to explain away evidence of God – which takes me right back to where I started: there is plenty of evidence, if you will accept it.

    1. @PreferLinux: I truly like your comment. Why shouldn’t there be a greater entity who is responsible for the laws of physics? However, most “modern” humans don’t need any father-like god in these days. Instead, they are worshiping their selfmade gods…

      I am honestly interested in your evidences that you experienced. Would you like to share them with us?

      1. I’m not really thinking of personal experiences, but rather of creation (Romans 1:19 – 23). Look up at the night sky (Psalm 19), or even at your own body, and consider the incredible complexity and design of it all. Many try to explain it all away with evolution (what I was primarily writing about above), but it isn’t the answer – not by a very long way. There are many things that evolution doesn’t even try to explain, and many more that it completely fails to explain. And there is no evidence for it (all supposed “proofs” of evolution or long ages either rely on variation within a kind (changes in the use of already-existing information), or are not “proof” at all (e.g. radioactive “dating”, which is full of assumptions and returns highly inaccurate dates)). The only reasonable explanation is a Creator.

  4. I just think it’s funny that you inadvertently also made a bible reference. Here’s Mark 7:15 for you:
    “There is nothing from without a man, that entering into him can defile him: but the things which come out of him, those are they that defile the man.”

    Also, he doesn’t “quote bible verses”, he just gives a reference. He’s not pushing it onto you, you can look it up if you want. James 1:2-4 is about perseverance, so quite fitting here.

    To your actual question: I don’t know either. But it seems to me that even among scientists, outspoken atheists are in the minority. Most seem to have the position that as long as someone’s faith does not interfere with their scientific methods, it’s all good.

  5. You have an interesting view on life. We take a *lot* of things on spec and do not question it. Do not think so? Open a coke and drink it. Nothing really happened huh? Now read the ingredients. They are not all there. You take it on faith that those are OK for you and will not kill you. The FDA makes sure of it. But that is on faith too. You read an article on CNN telling you how your shampoo is killing you. You can probably even dig up the papers they got it from. But you still take it on faith that the people who ran the experiment did it correctly. We let slide a lot of things on faith. So why do you decide to attack someone for doing the exact same thing you do every moment of your life? Before you criticize someone elses faith perhaps you should examine your own. Or have you already and found it lacking and find it easier to fling poo at others? You could do well to take the lessons from the bible to heart instead of what you are doing now.

  6. I would like to see how their results compare to a theoretically perfect supercomputer simulation of the same fluid dynamics. The later states would be interesting to see the mechanics of.

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