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I ran across a video recently that really caught my attention. It's been circling the internet over the past couple weeks, but I'm trying to figure out what's going on. Basically, it's a video of an outdoor water faucet which has water slowly running out of it. The water appears to be fake, almost made of plastic or glass, because the flow is so steady, but then the person recording puts their fingers into the stream and breaks it. All of the various people who have posted the video title it as being "laminar flow," but I'm not really sure if that's the correct terminology since the flow doesn't appear to be completely uniform. Many people believe that the video is fake, but it's so perfect that I don't think that could really be true. This youtube commenter created a great post that reflects my thoughts on that:

For people that think this is edited/frame edited.. the proper term is Compositing or VFX (Visual Effects). I'm a compositor and I have to say that if this isn't real, then whoever composited this has incredible talent. I don't see any artifacts that lead me to believe this isn't real. You would have needed to make a 3D rendering of the stream, make a camera movement path to match the movement in the video, create refractions through the 3D rendered stream, match the focus changes throughout the video... and a bunch of other things such as colour correcting and whatnot. All of this isn't difficult to do fairly well. However, this isn't just "fairly well." This is perfect. Matchmoving is crazy difficult to make look THIS good and the amount of time to tweak it could take a lifetime (and possibly admission into an insane asylum). And it's especially difficult to matchmove on a lower quality camera that has weird warping effects added to camera movement. You'd have to emulate not just movement but the camera artifacts. On top of that, perfect focus matching? Watching it at quarter speed I also noticed a detail. If you notice very carefully when he puts his hand in the stream you can see the wavy effect called the "Rayleigh-Plateau Instability." This happens in the stream right above where the water meets the hand. This is an incredibly subtle and unnoticeable detail that you can only see at a fraction of normal speed. I find it highly implausible that someone would go THIS detailed.

Anyhow, I'm basically wondering if it is possible for a stream of water to behave this way in the real world. If so, what is it the phenomenon called, and is there any way that I could possibly recreate it? These are the types of projects that I love and would really like to be able to recreate a stream of water like this if it is actually physically possible. Thanks everyone! Here's the link to the video: https://youtu.be/Ske2fgZgPs8

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  • $\begingroup$ If you're interested in the Rayleigh-Plateau Instability effect in a laminar flow of water, there's an interesting pop science video here: youtube.com/watch?v=DvtbQs7hWXw $\endgroup$ – Chappo Jan 12 at 11:07
  • $\begingroup$ ..."laminar flow," but I'm not really sure if that's the correct terminology since the flow doesn't appear to be completely uniform." Laminar flows do not have to be uniform. Flows over entire wings can be completely laminar under appropriate conditions, for example. $\endgroup$ – D. Halsey Jan 12 at 16:12
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That water is near freezing, judging by the snow nearby. This kicks its viscosity up to abnormal levels and strongly damps out any vorticity and flow instabilities.

If you are careful pouring motor oil at room temperature, you can get the stream of falling oil to exhibit creepy consistency too.

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