Siphon Questions Answered: Can Outflow Be Submerged?

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In summary: The conversation discusses the functionality of a siphon and how it works. It is explained that as long as the top of the water column at the output end is below the top of the water column at the supply end, the siphon will continue to flow due to gravity and vacuum pressure. The conversation also mentions how this effect can be observed using clear tubing in a fish tank. The question of whether there is a peer reviewed article on the siphon effect is raised, with one person stating their own understanding of the concept and the need for verification. In summary, the conversation discusses the mechanics of a siphon and its ability to function as long as certain conditions are met, and raises the question of a peer reviewed article on the
  • #1
frombc
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Hello, On a siphon, can the mouth of the outflow be submerged and still flow? If yes, what allows this to happen? Thank you!
 
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  • #2
frombc said:
Hello, On a siphon, can the mouth of the outflow be submerged and still flow? If yes, what allows this to happen? Thank you!


As long as the top of the water column of the output end is below the top of the water column of the supply end it will continue to flow.

As for the "why" a siphon works because gravity acts on the water in the siphon creating an area of low pressure at one end of the siphon. If a siphon is filled with water and one end is placed below the water surface gravity pulls the water down. This creates vacuum pressure behind the downward moving water. Since nature abhors a vacuum the water in the supply must be drawn along with the downward moving water. When the two water columns are the same height the water in the siphon is pulled down equally on both sides. When this happens the downward movement of the water stops, and once again because nature abhors a vacuum all flow stops.

You can see these effects more clearly by taking a section of clear tubing and submersing it in water until it is completely filled. Then you can lift the tubing in a manner that leaves both ends submerged but has the middle section above the water column. Even though the water it being pulled down by gravity in two directions the water remains in the elevated section of the tubing do to vacuum pressure. I have seen clear hard plastic tubes situated in this manner on top of fish tanks where the fish will swim up into the tube, and down the other side.
 
  • #3
frombc said:
On a siphon, can the mouth of the outflow be submerged and still flow?
Sure, as long as the mouth is not submerged too deep. (The level of fluid in the outflow tank must be below the level of fluid in the intake tank.)
 
  • #4
Thank you both for your replies. You've answered my question.
 
  • #5
Is there a peer reviewed (AJP or suchkinds) article on the siphon effect?

I've read all kinds of articles that talk about cavitation, tensile strength of water and other things which I think are totally irrelevant or at least not important to first order. My self-formulated understanding of the effect is very simple and based on nothing more than hydrostatic forces, but I've not read it anywhere. Moreover, my own explanation easily accounts for the maximum siphoning height found from experiment.

So, I need a reliable verification. Got one?
 
  • #6
I think I have the same understanding as you do, Gokul. A simple hydrostatic argument allows you to say whether the siphon will work or not. But once it starts flowing, you need to consider Bernoulli to find the actual pressure at various points in the fluid. (At least to first order.)
 

1. What is a siphon?

A siphon is a tube or pipe used to transfer liquids from a higher level to a lower level by the force of gravity. It works by creating a vacuum and allowing the liquid to flow from the higher level to the lower level.

2. How does a siphon work?

A siphon works by creating a vacuum in the tube, which pulls the liquid from the higher level down to the lower level. This vacuum is created by filling the tube with liquid and then allowing gravity to pull the liquid down and out of the tube.

3. Can a siphon work with the outflow submerged?

Yes, a siphon can work with the outflow submerged as long as the tube remains full of liquid and the end of the tube is below the surface of the liquid. The vacuum created will still pull the liquid through the tube and out of the submerged end.

4. What liquids can be siphoned?

Most liquids can be siphoned, including water, gasoline, and even thicker liquids like syrup or oil. It is important to note that liquids with a higher viscosity may require a larger diameter tube or more gravitational force to create the vacuum needed for siphoning.

5. Are there any safety concerns with using a siphon?

Yes, there are some safety concerns to be aware of when using a siphon. It is important to make sure the tube is clean and free of any debris or chemicals that could contaminate the liquid being siphoned. It is also important to use caution when working with flammable liquids and to properly dispose of the siphon after use.

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