Slapping Waterfalls: Can Pressure Move Fountains?

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Discussion Overview

The discussion revolves around the question of whether slapping a stream of water from a fountain can generate enough pressure to move the fountain itself. Participants explore the mechanics of water flow, pressure, and momentum transfer in the context of a shower fountain setup.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant proposes a scenario involving a fountain that can rotate and questions if slapping the water stream could move it based on pressure.
  • Several participants argue that the water does not provide a rigid transfer of force back to the fountain, suggesting that it cannot effectively transmit momentum.
  • Another participant notes that if the water stream remains intact, it might support waves that could impart some momentum to the fountain.
  • Concerns are raised about the density and velocity of the water stream, with a suggestion that most fountains produce a low-density stream that would not effectively transfer momentum.
  • One participant emphasizes that the condition of the stream remaining unbroken is stringent, as even moderate disturbances can cause it to break apart.
  • A later reply suggests that while it may be possible to affect the fountain, any resulting effect would be extremely weak.
  • There is a light-hearted exchange about freezing the stream, which leads to humorous remarks about the flow of glaciers.

Areas of Agreement / Disagreement

Participants express differing views on the potential for slapping the water stream to affect the fountain. While some argue it is unlikely or impossible, others suggest there may be a minimal effect under certain conditions. The discussion remains unresolved with no consensus reached.

Contextual Notes

The discussion includes assumptions about the nature of water flow, the density of the stream, and the conditions under which momentum transfer might occur. These factors are not fully explored or defined, leaving some aspects ambiguous.

kingofingo
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I Came up with that yesterday when i had a shower. So here it is.
Imagine a fount(i am that the word for the found that throw water under us)
in a shower that has a hole on the one side and hang on an ax that is set on the wall(inside the shower). The fount can turn easily right and left. So we make the fount to throw water under pressure. Now, we slap the waterfall with our hand. Is it possible debends the pressure of the waterfall to MOVE the fount slapping the water??Sorry for my terrible english.
 
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If I understand the question correctly, the answer is no. The water doesn't provide a rigid transfer of force back to the spout.
 
If I understand the question correctly, the answer is no. The water isn't solid enough to transfer force up or down to the fount.
 
If the water stream hasn't broken apart then it can support waves which may impart momentum to the fountain.
 
But wouldn't that be dependent upon it being a very high-density stream? Most fountains deliver a low-velocity, low-density stream. Smacking it with something will just disrupt the upward flow, not transfer momentum to the nozzle.
 
The condition that the stream hasn't already broken apart is fairly stringent and any wave propagation up the stream (essentially supported by surface tension) will be minimal since even moderate amplitude will itself cause the stream to break up!
 
Thanks a lot for your respond.
Tide i don't really get your answer:-)
Is impossible to effect the fount?
 
I am saying it may be possible but any effect would be extremely weak.
 
If you freeze the stream, on the other hand...:biggrin:
 
  • #10
... in which case it won't flow very fast! :)
 
  • #11
Dang! You've got an answer for everything.:-p
 
  • #12
Glaciers flow. Kind of...
 
  • #13
Danger said:
Dang! You've got an answer for everything.:-p

But you make it so EASY! :wink:
 
  • #14
Looks like the beginning of a beautiful war.:-p
I'll catch you in GD when I'm not so tired.:biggrin:
 

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