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4 years ago by Animats

This seems to be a known technology. Here's a paper: "THREE-DIMENSIONAL SIMULATION OF A VALVELESS PUMP" J. Shin and H.J.Sung", Kaist (2010) [1] It's not quite the same, though. Rather than using turbulence, it uses an impedance mismatch as an obstacle to flow. The idea is to have two impedance mismatches in opposite directions from the pinch point, but at different distances. You get some reflection from each impedance mismatch. So if you choose the right driving frequency, you get the reflections opposing movement in one direction and helping it in the other.

This is a lot like the way some antennas are driven. RF also has impedance mismatches. But not turbulence. (Fortunately, or RF engineering would be really hard.)

[1] flow.kaist.ac.kr/bbs/download2.php?bo_table=pro_domestic&wr_id=93&no=0

4 years ago by vanderZwan

There's also the Tesla valve, which of course isn't a pump by itself but uses similar principles

https://en.wikipedia.org/wiki/Tesla_valve

4 years ago by undefined

[deleted]

4 years ago by KMag

It would be interesting to see if something like this could improve efficiency in valveless pulse jets. Valveless pulse jets rely on different inertia in two air paths to pull fresh air back in one of the exhaust pipes to refill the combustion chamber.

Valveless pulse jets are loud and inefficient, but they're reliable, tolerant of manufacturing defects, and cheap to produce. Of course, acoustic effects providing the only compression above ambient pressure is going to fundamentally limit combustion pressures and temperatures, and thereby thermodynamic efficiency, but I think valveless pulse jets operate significantly below their Carnot / Brayton efficiencies.

4 years ago by jarfil

Isn't this the same principle behind a Tesla valve?

4 years ago by robocat

Same same but different? Good video of a Tesla valve:

https://www.google.com/search?q=youtube+%22Tesla+Valve+Expla...

4 years ago by colechristensen

I can see where you're coming from, being on it relying on differential pressures and turbulence to ensure certain flow characteristics... but then again, I wouldn't really say there was any particular unique concept at work here.

4 years ago by andrewflnr

There is still so much science to do with simple systems. Even if fundamental physics gets solved, there will be plenty of new discoveries to make.

4 years ago by tobmlt

I wonder if this is interesting to look at topologicaly? Flow dynamics picks out the network connectivity/handedness/etc... Maybe I am over thinking it while simultaneously under thinking it. ;)

Paging V. I. Arnold just in case.

4 years ago by spiritplumber

Wonder if it works with liquids

4 years ago by andrewflnr

At least some of the tests were with water, so, yes?

4 years ago by puddingnomeat

does this flow effect work with the water analogy of electricity?

4 years ago by poleguy

I had to google it. It seems like it's at least plausible that it might: https://pubs.acs.org/doi/pdf/10.1021/nl070935e

4 years ago by andrewcchen

The circulator[1] is an analogous component in rf, it send the incident power from any port down to the next port, so you can take one port to be the bidirectional connection, and it splits the signal into transmit and receive connections.

[1] https://en.wikipedia.org/wiki/Circulator

4 years ago by jcims

Just realized if it did this would make a very simple rectifier. I guess you could test it by putting ends of a wire with a galvanometer on it to different parts of an antenna and see if you get a current.

4 years ago by jojobas

This relies on inertia so probably not.

4 years ago by jcims

Inductance is similar to inertia in the water model of electricity.

4 years ago by jojobas

Yes, but it's not directional. You don't get to make a T-joint of three coils and have the current follow the top bar as it's a straight line.

4 years ago by CyberDildonics

Diodes don't work based on inductance.

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