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.
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?
I don’t think it’s possible to build a suction cup (or in fact any climbing tool) which will work 100% of the time against any countermeasure. However this design does seem a significant step forward from existing suction cups.
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.
Presumably you were downvoted because your question suggests that you haven't actually read the article, which does mention how it compares to other powered suction (i.e. "vacuum pump") devices.
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).
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?
Pretty much anyone over 40 doing a home video in their garage is going to come across like that. It's really unfortunate, but appearances do matter, a lot.
In this case, besides the appearances, what the guy is demonstrating in the videos seems legit.
Here's an earlier video where he explains what he believes is the effect at work, with a simple demonstration: https://youtu.be/I3g0CcLzC6I
It would be awesome if a youtuber like Steve Mould or Dustin from SmarterEveryDay did a video on this.
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.
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.
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.
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.
Well for one, the linked video example of the Styrofoam plates and hair dryer (shown right before the immersion blender) is definitely due to Bernoulli's law. See https://en.wikipedia.org/wiki/Bernoulli_grip
As for the immersion blender, intuition should tell you that the same principle should/or at the very least… might apply. Now it could very well not apply (but I'm quite confident that it does). To really prove if it does or not, one would have to do the rigorous math involved, which would include deriving the stream function for the flow situation, verifying if conditions allow for applying Bernoulli's principle, then applying the principle and verifying if it matches experimental observations... This is would be non-trivial to do (judging simply by the geometries involved) so I'm not even going to attempt do this…
However, I’ll try explaining the gist of the idea:
Bernoulli’s principle basically states that, within a flow of constant energy, when a fluid speeds up, it is corresponded with a drop in pressure and vice versa. Now looking at the immersion blender, intuition (and essentially conservation of mass) suggests that the fluid should be moving fastest between the edges of the blender/blade and the boundaries of the container/cup (i.e. areas where there’s very little space near the moving blender parts). Outside these regions, intuition would suggest the fluid is moving relatively slowly (e.g. near the top of the water level in the container cup). Since the fluid appears to move, and likely cross these regions (i.e. undergoes speeding up/slowing down), Bernoulli’s principle states that we should expect to see a pressure differential between these regions, where faster moving water regions should be at a lower pressure (i.e. acting as a vacuum / suction cup).
But again, whether or not this idea is true and is valid would have to be mathematically and experimentally verified…
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.
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.
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_...