New suction-cup system spins water to stick to rough surfaces

https://newatlas.com/science/zpd-suction-rough-surfaces/

by anon463637 • 7 years ago

167 33 7 years ago

jcims• 7 years ago

No idea if this is actually a new idea but it's definitely new to me and I love seeing it. What a cool concept, likely to be a few applications in industry beyond spiderbots.

catalogia• 7 years ago

Is this the same mechanism as the immersion blender trick? (https://youtu.be/TrZyuCh9df0?t=424)

Rury2• 7 years ago

No, I believe the immersion blender trick can be explained by https://en.wikipedia.org/wiki/Bernoulli%27s_principle

Whereas the suction cups in the article, use spinning water as a way to seal suction cups on rough surfaces (the water fills in crevices of rough surfaces I presume, allowing the suction cup to seal). The water is also spinning (i.e. it has an inertial force) so that it counteracts the vacuum pressure in the center of the suction cup.

jtbayly2• 7 years ago

Hmmm. At a glance I can’t figure out how Bernoulli’s law applies. The blender trick looks very similar to the original article to me.

Could anybody explain in more detail?

ta12345678902• 7 years ago

Pretty cool. Reminded me of what this guy is doing, he calls it "orthosonic lift": https://youtu.be/kG6vXGidQbo

Some more info: http://sciencechatforum.com/viewtopic.php?nomobile=1&f=77&t=...

I believe he has a couple of patents on the technology, but not sure he'll ever get around to making something practical with it.

jl27182• 7 years ago

The patent won’t hold. We have prior art from alien spacecraft for decades now.

Most of our current propulsion and lift mechanisms are based on momentum transfer, which has many problems in air. His work makes me think there are a lot more efficient mechanisms to be discovered.

jl27182• 7 years ago

okay; sorry. I was trying to compliment him on something I found interesting by alluding to it being alien technology. I took aeronautical engineering a long time ago, and I've never seen anything like this, so maybe it's just a foolish amazement.

NougatRillettes2• 7 years ago

This has many of the red flags for "technological" development that won't withstand scientific scrutiny.

jtbayly2• 7 years ago

What flags, specifically?

113• 7 years ago

Have to agree, he sounds a lot like those "infinite energy" guys that were around a few years ago.

war1025• 7 years ago

Just wanted to throw my opinion into the mix.

I watched multiple of the videos he has listed and from what I can tell the phenomenon he is demonstrating is real and reproducible.

Whether or not he's crazy, who's to say?

czr• 7 years ago

actual paper https://aip.scitation.org/doi/10.1063/1.5129958

video 1 (response measurement): https://aip.scitation.org/doi/suppl/10.1063/1.5129958/suppl_...

video 2 (picking up block): https://aip.scitation.org/doi/suppl/10.1063/1.5129958/suppl_...

video 3 (hexapod): https://aip.scitation.org/doi/suppl/10.1063/1.5129958/suppl_...

video 4 (human climbing tiled wall): https://aip.scitation.org/doi/suppl/10.1063/1.5129958/suppl_...

video 5 (human climbing concrete wall): https://aip.scitation.org/doi/suppl/10.1063/1.5129958/suppl_...

keanzu• 7 years ago

The videos are great, consumes a lot less water than I imagined. Seems like most of the water is lost during the de-suction process, if they can scavenge that it could really cut the water consumption down nearly to zero.

samstave• 7 years ago

If they have an additional ring around the outside of each cup, could they not suction the water back into the system?

Also, wouldnt this be easily defeatable with small dowel protruding "thorns" - or dimples, as on a golf ball - maybe alternating convex/concave dimple patterns? or other ridges?

Tepix• 7 years ago

Speed is also an issue, the video is speed up 2x and the progress is still quite slow.

logicallee2• 7 years ago

This is very interesting. I wonder how the power use compares with achieving a similar effect using a vacuum pump.

logicallee2• 7 years ago

Edit: I got downvoted. Is a powered vacuum pump not possible in this application? (Like putting a vacuum cleaner nozzle against the wall, possibly using a more powerful motor than usual, for more suction.) I think it's a fair question but maybe I'm way off base here.

flashman• 7 years ago

Kind of similar to the reason you'd wet a suction cup before using it: the water helps plug any small air gaps. But in this version, a fan spins the water and air inside the cup, with the heavier water being forced to the edge, and any water leakage being replaced from a reservoir.

raihansaputra• 7 years ago

Quick links to diagrams explaining how it works:

https://aip.scitation.org/na101/home/literatum/publisher/aip...

(from the actual paper link from czr: https://aip.scitation.org/doi/10.1063/1.5129958)

Iv• 7 years ago

Thanks! That's a great concept!

One way of explaining it would be that instead of leaking air, it leaks sealing water without suffering dpressurization in the process. Really neat.

AliAdams• 7 years ago

What about ferromagnetic fluid? You can still spin it if you are aiming to push it 'centrifugally' into the features of the vacuum boundary, but you shouldn't lose a lot during the detachment.

(Plus it looks much more sci-fi.)

ambyra• 7 years ago

Arduino controlled real live squid with water backpack. That’s the future.

I wonder if some sort of jelly would work to do the same thing, like a snail. Or a dynamic cup surface that conforms to the wall better.

NougatRillettes2• 7 years ago

My understanding of it after a quick read of the paper: you want to make a suction cup. The usual way is with a solid cup (think plastic) with a softer rubber-like ring around it. Near the ring, you will have atmospheric pressure (high) outside, and vacuum pressure (low) inside, so if the ring doesn't make perfect contact with the surface, some air is going to come in and ruin you vacuum. What they are doing is that they are rotating a bit of water in the suction cup, which because of centrifugal force will come close to the suction cup frontier in a ring-like shape. This water ring will -- thanks to fluid mechanics black magic -- have a different pressure at its exterior and its interior. Its interior pressure will necessarily be the same as the vacuum, and you can make it so that the pressure outside is the same as the atmospheric pressure, hence, according to this paper, if the rubber ring fails to make hermetic contact, air won't come in because at the frontier of the cup, the pressure is the same both outside (atmosphere) and inside (exterior of the water ring).

thebiss• 7 years ago

Does the water on the innermost edge of the rotating ring, which is exposed to the vacuum, NOT vaporize because the absolute pressure is still above 10kPa (100kPa atmospheric - 80kPa vacuum)? [0]

Will the seal slowly evaporate away or absorb into a porous surface like concrete?

[0] https://en.m.wikipedia.org/wiki/File:Phase_diagram_of_water....

jakedata• 7 years ago

I can't say I am super looking forward to hexapod wall climbing robots.

Terr_• 7 years ago

The resulting inertial force generates a steep pressure gradient, allowing a high vacuum to be maintained at the center of the cup's vacuum zone

Sounds like a "momentum transfer" vacuum pump, shaped so that the output side bleeds out along the rim.

https://en.wikipedia.org/wiki/Vacuum_pump#Momentum_transfer_...

New suction-cup system spins water to stick to rough surfaces

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