[HN Gopher] A bit of fluid mechanics from scratch not from scratch
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       A bit of fluid mechanics from scratch not from scratch
        
       Author : surprisetalk
       Score  : 26 points
       Date   : 2026-03-02 14:52 UTC (8 hours ago)
        
 (HTM) web link (tsvibt.blogspot.com)
 (TXT) w3m dump (tsvibt.blogspot.com)
        
       | barrenko wrote:
       | > in case someone wants to get nerdsniped
       | https://github.com/kamilazdybal/fluid-toolbox
        
       | MarkusQ wrote:
       | Really nice to see the process of thinking it through. This sort
       | of thing gives a much better insight than just memorizing
       | formulas.
        
       | gpm wrote:
       | > 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.
        
       | alienbaby wrote:
       | Unfortunately nobody in the UK can see the images in the blog,
       | 'cause imgur
        
       | NewsaHackO wrote:
       | > 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.
        
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       (page generated 2026-03-02 23:02 UTC)