Comments by "geemy" (@geemy9675) on "Dr Ben Miles" channel.

  1. e ink does it with tiny spheres that are black on one side and white on the other and can be switched with electric field. they don't have a lot of contrast though but I guess if you make the black side blacker and the white side whiter it can help. they have done it on prototype cars (BMW)
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  2. I think it is possible to analyze the problem in a simpler way by breaking it down. 1/ pumping fluid quickly inside a simple tube with an entry and exit generates strong pushing thrust at the exit, and weak pulling thrust at the entry. this can probably be measured independently using load cells. the thrust can be converted into movement/rotation or a stationary force/torque, it doesnt matter. this is highlighted by jet ski having the jet exit direction controling the thrust, while the intake is directed forward and downward (not straight forward) and doesnt change direction for forward or reverse operation 2/ if you now have several exits, and several entries, the overall thrust will be approximately the sum of the exit thrusts 3/ if exit thrusts cancel each others approximately, then the intake thrusts can become prevalent 4/ if exits streams point at each or at fixed objects other weird turbulence and vortices will happen and create additional secondary effects way more complicated to study and probably cant be predicted without numeric simulation and understood through experimentation 5/ even it the main exit thrusts cancel each other, those secondary effect could still outweight intake thrusts. THIS IS probably the ONLY CONCLUSIION of this experiment? 6/ the rotating part of a sprinkler should be analyzed like a freely rotating system with entries and exits for fluid to be pumped through 7/ the traditional sprinkler has several exits which combined generate a clear torque, stronger than any effec onthe sucking side, the intakes don't matter 8/ the generic sucking sprinkler achieved using any sprinkler, with reversed pumping action, is designed wihout any attention to the blowing side , and because of this, has undetermined behavior 8/ the sprinkler shown in this experiment is seemingly designed to cancel the effects of the blowing side to show the effect of the sucking side (by using symetrical exits, pointing at the center, but failed to do so because asymetrical flows and resulting asymetrical vortices
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  3.  @clockworkvanhellsing372  yeah, it seems like the conclusion of the experiment is that while the "blowing" sprinkler characteristics depends mostly on the design of the arms, the reversed "sucking" sprinkler characteristics depends more on the internals. they actually just designed an inefficient, inside out, blowing sprinkler! But its still a very interesting example of how apparently simple physics problem can be complicated. Probably 99% of the comments (including miine) suggesting to modify the experiment fail to take everything into account
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  4. So, am I crazy, or in the end, the reversed sucking sprinkler is actually just an inside out blowing sprinkler, pointed towards the inside, with poorly designed arms that point at each other (center), canceling each other, instead of having a clearly defined directions, and relying on secondary turbulences to generate rotation. someone needs to 3d print a better version that probably wouldn't even need advanced bearings, or complex design to avoid vibrations. the traditional sprinkler works without these. I can imagine 3 designs, with inner arms bent in the same or opposite side as the outer ones, and one with arms bended upwards and a long straght vertical tube to let the flow settle after the last bend, and try to isolate the effect of the outer arms
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  5. what happens if the tubes from the sprinklers arms continue inside and bend toward vertical exit of the sprinkler, joining together smoothly so that the flow stays laminar?
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