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Water that sucks while filling buckets

  1. Jul 26, 2012 #1
    While filling a watering bucket for the garden plants I noticed there was a small suction pulling the nozzle of the hose down and 'sucking' to the bottom - yet the hose was still adding water to the bucket.

    The hose had the 'standard' nozzle, which is screwed onto the end of the hose. It is longish and has a barrel that can be turned to get water out. The stream goes from very wide spray to the 'focused' jet stream of water.

    I had the nozzle set to the wide spray - about 2 or 3 turns to open the water stream.

    I started the filling and after a few seconds of the loud spraying sound of the water into the water, I pushed the hose/nozzle into the water to reduce the noise and when the nozzle tip was a 1/4 inch or so above the floor of the water bucket the nozzle was pulled down and came into contact bottom and stayed there with a slight suction. It was easy to feel the tug on the hose/nozzle while lifting it off the bottom and back and off again...

    Yes, the water was spraying the whole time and having the suction effect.

    This seems totally odd. The water pressure from the hose is pushing pretty hard is there some kind of vortex produced that causes this or...?
     
  2. jcsd
  3. Jul 26, 2012 #2

    Danger

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    Welcome to PF.
    I've never heard of such a thing, but I suspect that you're correct regarding some sort of vacuum effect being caused by the flow. It's really difficult to envision just what might be happening, though.
     
  4. Jul 26, 2012 #3
    You might also note that you cannot (easily) press the nozzle tight enough against the bottom of the bucket to stop the flow.
     
  5. Jul 26, 2012 #4
    Bernoulli?
     
  6. Jul 26, 2012 #5

    Danger

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    That's what I was thinking, but it seems to me that it would be more likely to occur with the nozzle set to narrow high-speed flow. This is far enough beyond me that I'm just going to lie in the weeds and wait for an answer from someone else.
     
  7. Jul 26, 2012 #6
    Also see it what you are feeling is a cessation of the reaction forces, and the nozzle is neither drawn down or pushing away from the bucket bottom, or an actual pull towards the bottom of the bucket.

    What I'm suggesting is, you might not be feeling suction, just a neutralization of the reaction force.
     
  8. Jul 26, 2012 #7
    It'll happen most any time a fluid moving a two different speeds. Faster moving where the water is just going past the edge of the threads of the nozzle. And slow above and around.
     
  9. Jul 26, 2012 #8

    DaveC426913

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    You say the spray was set on wide.

    I wonder if the nozzle was causing cavitation. Water is pushing outward all around the outer area of the nozzle. There'd be a partial vacuum in the cone-shaped area directly under the nozzle.
     
  10. Jul 27, 2012 #9
    What the actual answer will be( or if DaveC426913 has a strong candidate answer ) it is an easy classroom experiment: OK, let's get-up, out of our chairs and go outside...

    Thanks for everyone's thoughts on this oddity, gardening can be thought provoking!
     
  11. Jul 27, 2012 #10

    NascentOxygen

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    Definitely suction. A Bernoulli force. The same principle that will prevent you blowing a ping pong ball out of a funnel. :smile:
     
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