• barrenko 2 days ago

    > in case someone wants to get nerdsniped https://github.com/kamilazdybal/fluid-toolbox

    • gpm 2 days ago

      > Ok, so, it’s the same as before, but the outlet of the spout is now significantly deeper / lower. So the speed of the water should be higher, right?

      > Ok, but if the water is faster at the bottom of the long spout… We could view the top part of this system as an exact copy of the short-spout version. At the interface between the tank bottom and the pipe-spout, the velocity of the water should be the same as in the no-pipe version, right? But that means the water inside the pipe is accelerating inside the pipe:

      No, it's not the exact same. In the top part of the long-spout system there's a lack of airpressure holding the water above it back compared to the short-spout, and quite a bit of cohesion in the water pulling the water above it down faster if the lack of air pressure isn't enough. The water in the whole system moves faster as a result.

      You'd theoretically get the air (actually vacuum) bubble if you ran the experiment in a vacuum with a liquid that has no cohesion... liquids with no cohesion are otherwise known as gasses though and behave differently in other ways as well.

      • tbt 18 hours ago

        Ohhh, oops, good point, thanks.

      • NewsaHackO 2 days ago

        > As everyone learns in kindergarten, the speed at which water comes out of a spout in a tank depends on the height

        What kindergarten did you go to? Maybe my public kindergarten education was seriously lacking.

        • tbt 18 hours ago

          Oh sorry that was a joke. (Though you could teach that in kindergarten.) When I was in undergrad I had the privilege of taking Laszlo Babai's combinatorics class. I don't recall exactly how he phrased it, but he would say things like "As everyone learns in kindergarten, the powerset of [n] has size 2^n.".

          • NewsaHackO 14 hours ago

            Oh my bad, good article though.

        • MarkusQ 2 days ago

          Really nice to see the process of thinking it through. This sort of thing gives a much better insight than just memorizing formulas.

          • alienbaby 2 days ago

            Unfortunately nobody in the UK can see the images in the blog, 'cause imgur

            • tbt 18 hours ago

              Sigh, thanks for letting me know. Ok since this is the ~third time someone has said this, I'll try to figure out a convenient solution (I guess hosting images on github?). Just FYI a VPN should let you see imgur images.

              • alienbaby 12 hours ago

                Thankyou :)