Water that sucks while filling buckets

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SUMMARY

The discussion centers on the phenomenon of suction experienced while filling a watering bucket using a standard hose nozzle. The nozzle, set to a wide spray, creates a suction effect when submerged just above the bottom of the bucket, despite water continuously flowing from it. Participants suggest that this effect may be attributed to Bernoulli's principle or cavitation, where varying fluid speeds create a partial vacuum beneath the nozzle. The conversation highlights the complexities of fluid dynamics in practical gardening scenarios.

PREREQUISITES
  • Understanding of Bernoulli's principle
  • Basic knowledge of fluid dynamics
  • Familiarity with cavitation phenomena
  • Experience with garden watering systems and hose nozzles
NEXT STEPS
  • Research Bernoulli's principle in fluid dynamics
  • Explore the concept of cavitation and its effects in fluid flow
  • Investigate the design and functionality of hose nozzles
  • Conduct experiments demonstrating fluid dynamics principles in gardening
USEFUL FOR

Gardeners, fluid dynamics enthusiasts, and anyone interested in the practical applications of physics in everyday tasks will benefit from this discussion.

bbondi
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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...?
 
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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.
 
You might also note that you cannot (easily) press the nozzle tight enough against the bottom of the bucket to stop the flow.
 
Bernoulli?
 
Jakeus314 said:
Bernoulli?

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.
 
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.
 
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.
 
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.
 
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!
 
  • #10
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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