How do fluids actually mix?

This project has been kicking around in my head for years and I finally got around to building it! (Freshly inspired to make ordering/stochastic art after someone sent me a video of Ivan Miranda's awesome marble clock.) This machine separates ink from water with a reverse osmosis membrane, then mixes the ink and water back together again. It sounds circular and useless, and it is, but it's also really cool! in this first video, I focus mostly on the fluid dynamics and complexity that shows up even just in a tiny clear pipe!

Special thanks to my top Patreon supporters!
birdiesnbritts
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Bonus thanks to Patreon supporter Christian Wölke, who found a big error in one of my graphics!

Media Credits:

0:00 What does it do?
1:48 Water is clear
2:45 Turbulent flow
4:40 Laminar flow
8:28 Fluid motion tracking
9:49 Project origin
11:38 Reverse osmosis membranes
13:05 Under the hood
16:08 Trial and error

[zaftnotameni]

legend says if you say laminar flow in front of the mirror 3 times Destin shows up

[iteerrex]

“It’s not hoarding, it’s planning ahead.” 😁👍 To a scientist/engineer all recourse are “Precious”.

[bl]

Have you tried running the water backward in the reverse osmosis tube? In water treatment plants, they do that to prevent clogging and preserve the throughput. They call this 'backwashing' or 'backflushing', but the don't deal with ink.

[dustinmorrison]

19:11 I love the reference to This Old Tony.

[Patchnote.]

I love how Destin's on a monitor in the background when you're talking about just how laminar it is. 8:45

[unvergebeneid]

Pro tip: set your quality to 4K for this video, even if you don't have a 4K screen. Even on 1440p, the Youtube compression algorithm does a real number on these swirls.

[dwang]

Different types of flow?! Countdown til Destin shows up! 🎉🎉🎉

[WrylyRiley]

There are microfluidic devices called spiral separators. These are usually use separate different cells based on density. Probably not useful for sorting ink, but might be worth a try for fluorescent polystyrene particles?

[vlachen]

There are two important phrases that will cover most of your metal working projects:
1) Beat to fit, paint to match.
2) Grinder and paint make me the welder I ain't.

[DracoGalboy]

The obligatory ToT reference now that you have a welder was perfect

[SemUwU]

The only thing more hypnotic than that tube structure is your lovely explanation

[Genubath]

17:55 The problem you had with the endcaps leaking might not actually be solved. Waterproofing 3d prints is notoriously hard because of the pores they have between the layers. This can be helped by extra perimeters and higher temperatures like you did, or smoothing the part by dissolving the surface with isopropyl alcohol vapors. However, most 3D printable plastics (like PLA and PETG which you used) are hydroscopic, which means that the plastic itself will absorb water. At very high pressure differences, like your 100 psi chamber, the water will still be forced through the plastic. A lot of submersibles with 3d printed parts have the same problem. You can try high-impact polystyrene (HIPS), which is not very hydroscopic.

[BluBr]

One of the most valuable channels on YouTube

[alext]

We should all be so lucky as to have some mildly diluted ink sitting around. You never know.

[gljames]

That thing looks insane. This and Steve Mold's mica setup are showing really cool fluid dynamics.

[DerSolinski]

What you want is ultrasonic separation.
This is used in grand scale industrial applications.
Basically using standing waves to "catch" particles.
But be warned, that's a rabbit hole on it's own.

[kaibroeking]

Cool project!
I also liked the "supposedly working" quip: that's the hallmark of fascinating physics: you may end up in a phase when you do nothing other than sit mesmerized and stare at whatever you have built.
The story here in Göttingen goes that Max von Laue sat for half an hour just staring right at an x-ray tube with a screen in front of it when first being shown his crystallographic patterns.

[Sonnell]

You having this many subscribers kinda give me hope regarding humanity.
Because your content is pure science, wonder, understanding...

[ActualChrist]

Crazy how mesmerizing it actually is though

[sushantmanandhar]

I know everything in this video from fluid mechanics class but getting to watch it explicitly in a video is why I love this channel so much