[imperator]

I'm the one who made that 3D printed Tesla Valve shown in the pictures and video. I'm currently inventing a jet engine with no moving parts. If anyone wants to ask questions about the valve's workings or about Tesla, go right ahead.

[ChuckMcM]

Very cool, it would be interesting to build one (large) which would be wave pumped. You could cast it out of concrete I suspect. The idea being that waves would push into the end and then the flow back out would be self resisted, this would allow the wave energy to pump seawater up a bit. Then you provide a drain which runs through a micro-hydro station.

Would be fascinating to see what rate of wave action you would need to keep the flow going up hill.

On a pure art level building a pool on the beach that was filled with wave action like this would be kind of fun.

[akkartik]

It's a cool idea, but you might want to just build it with a traditional valve. I think the Tesla valve relies on moving fluid. If you just submerged it half way water would leak out in the wrong direction. So it won't work well for applications in the style of Maxwell's Demon.

[ChuckMcM]

So there is a place off of Monetery I believe where there are pipes that extend out into the ocean from the beach. Waves coming into the beach push water up the pipes, the other end of the pipe up on the shore has sort of a pipe organ type end with a flapper valve so it plays one note when the water rushes in and another when it rushes out.

Imagine a square tube that at one end underwater is just an open pipe which connects with this square tube which goes up out of the water on the beach to a pool which is say 10' above the water line. The pool has a drain which feeds a square trough going back down into the water.

The trough has a micro-hydro wheel in it. Or just for fun a pelton water wheel type wheel which drives an animated sculpture.

The interesting question for me, is this; Can the Tesla valve reduce the back flow of sea water enough that the following wave arrives with the valve still holding water?

Intuitively you can see that if the valve is 'full' when the wave returns then the next wave will push its mass worth out the top of the valve. If the valve is say 'half' full then the next wave should fill it and every wave after that should dump a 'half' wave's worth of water into the pool. This would be a good problem to set up for students learning computational fluid dynamics (CFD) as they could vary things like the angle of the elements, their size, and their quantity and characterize the abilities of the valve for various fluids.

Anyway, its a really interesting gizmo.

[imperator]

Well. Describing our ideas without a diagram breaks down rapidly. I imagined a valve bobbing in the water, slowly elevating the water in a reservoir with each wave undulation. Thinking about it more, the problem would be an eventual equalization in pressure. But of course, I read this paragraph again and there all ways of imagining what the words are saying. If we were to really understand each other, we'd need to whiteboard.

I'm not sure that a Tesla Valve would be all that useful for tapping wave motion now that I think of it. It might not work. One way to think of it is to imagine using a one way ball valve. That has helped me in the past from ascribing too much magic or revolutionary nature to the Tesla Valve.

[mikeknoop]

Not moving water, but the potential for moving water, a pressure gradient.

[seclorum]

The kind you get in ocean currents, where such things a self-constructing Tesla valves are probably out there, somewhere, already ..

[imperator]

That's a good idea. I've seen some of the wave generator concepts out there, and everyone seems to be trying different concepts for harnessing those oscillations. No one has it nailed down yet. One of the most intriguing mechanisms I've seen is this oscillating submersible wing: http://liquidr.com/technology/wave-glider-concept/

[z92]

If you hold the valve vertically and pour water through the wrong side, water will eventually start to fall from the other side when all those cavities inside the valve get overflown --- is that correct?

[apu]

I'm currently inventing a jet engine with no moving parts

A ramjet?

[imperator]

My jet engine is unique. There are actually many no-moving-parts jets. Each with different drawbacks. A ramjet cannot start from a static position, mine can start from a static position.

If anyone is interested, there are some very cool no-moving-parts jets that aren't as well known as ramjets: The lockwood hiller pulsejet is a pulsejet that doesn't need reed valves. http://aardvark.co.nz/pjet/valveless.htm

The Gluhareff Pressure jet is also a neat example. https://en.wikipedia.org/wiki/Gluhareff_Pressure_Jet

[sbierwagen]

A pulsejet based on the Tesla valve?

So, like that prototype Bruce Simpson was talking about ten years ago?

https://webcache.googleusercontent.com/search?q=cache:UX5eNg...

[marshray]

How small would you have to make one that could check the airflow caused by sound waves?

Could you make an array of them oriented perpendicular to the plane, like a sheet?

Could you make it light enough to float on sound?

What kinds of things might it be good for? Sound dampening?

Could a paddlewheel configuration extract energy from air or liquid flow in any direction?

[imperator]

The current use for Tesla Valves is in microfluidics. On the macro level, people generally use one way valves that have moving parts. To harness the flow of a fluid being acoustically pumped, I don't know what it would take.

You could make an array of them perpendicular to a plane. Perhaps, by etching them into silicon. On a macro scale, you could machine them with a CNC machine, or even with hand tools depending on your tolerances.

For sound, you energy density is rather low, so the material you wish to propel would have to be incredibly light. And you would probably have better luck trying to lift a plate of some super light material. The Tesla Valve is most useful as a device where you want to check the flow from moving one way.

Anywhere, where having a moving part is a pain in the butt, and you want a more robust system. When you're etching things into silicon, generally, you want to avoid have to make lots of tiny micromechanisms.

As a paddlewheel, it would probably not make sense to use the Tesla Valve. Turbines are well understood. If you want to make rotary motion, that's the way to go.

[aidenn0]

Have you made a rotationally symmetrical version of that flow, or are you going to try to make flattened jet? The biggest problem I've seen with valveless jets like this are that it works great in 2d, but rectangular cross-sections don't do well under high-pressures.

[imperator]

I have done lots of experiments with 3D versions of this valve. I even did some with a traveling rotation along the axis, so that it looked like a helix. Unfortunately, those were duds, though the looked beautiful.

My current jet engine work does not include a Tesla Valve, though much of it is inspired by it. When I began, I imagined using a pulse jet, and attaching an axialy rotated tesla valve to the front of it, in order to replace the reed valves. I eventually moved away from pulsed combustion though. Too noisy and not the pressure levels I wanted.

[recusancy]

You should do an AMA on reddit.

[imperator]

Someone did a TIL on reddit and I popped in to answer questions there, too. http://www.reddit.com/r/todayilearned/comments/obyxj/til_tha...

[samstave]

After seeing the pic of the valve you 3D printed, it would seem that making a jig for a router to cut that patern out would be better than printing the valve itself.

And seems like routing one out of aluminum on a CNC would be good as well.

[iamwil]

Weird. I'm the one that submitted the story. You joined HN one day after I did.