How Does a Siphon Work with Different Liquid Heights and Pressures?

In summary, the conversation discusses a siphon with a liquid of density P and negligible viscosity. The bottom of the tube is positioned at point A d + h1 from point B, and extracts the liquid at point C d + h1 + h2 from the top of the siphon. The conversation also raises questions about the speed of the liquid at point C, the pressure at topmost point B, and the maximum height that a siphon can lift water. The velocity is assumed to be constant due to no changes in area, but it is questioned if the pressure change as the water level drops will affect the velocity. Furthermore, the pressure difference that allows the siphon to work is also discussed, with a request
  • #1
Destrio
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Siphon with a liquid of density P and negligible viscosity. With the bottom of the tube in the contained at point A d + h1 from point B at the top of the siphon, and the bottom of the tube extracting the liquid at point C d + h1 + h2 from the top of the siphon and h2 away from point a. (All distances are vertical).
a) With what speed does the liquid emerge from tube at C?
b) What is the pressure at topmost point B?
c) What is the greatest height that a siphon may lift water?

I figure since there are no changes in area, the velocity must be constant at all point in the tube. But as the water level drops, will the pressure in the siphon change, causing the velocity to drop?
 
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  • #2
What is the pressure difference that is making the siphon work?

You have not said what is d. Give a better description of the whole apparatus.
 
  • #3


a) The speed at which the liquid emerges from tube C can be calculated using the Bernoulli's equation, which states that the total pressure at any point in a fluid system is equal to the sum of the static pressure, dynamic pressure, and potential energy per unit volume. In this case, the dynamic pressure can be neglected due to the negligible viscosity of the liquid. Therefore, the speed of the liquid at C can be calculated using the equation v = √(2gh2), where g is the acceleration due to gravity, h2 is the distance from point C to the top of the siphon, and v is the speed of the liquid.

b) The pressure at the topmost point B can be calculated using the equation P = ρgh1, where ρ is the density of the liquid, g is the acceleration due to gravity, and h1 is the distance from point B to the bottom of the siphon. This is the pressure exerted by the weight of the liquid in the siphon.

c) The maximum height that a siphon can lift water is limited by the atmospheric pressure. As the liquid rises in the siphon, the pressure at the topmost point B will decrease due to the weight of the liquid in the siphon. Once the pressure at point B becomes equal to the atmospheric pressure, the siphon will stop working. Therefore, the greatest height that a siphon can lift water is equal to the difference between the atmospheric pressure and the pressure at point B. This can be calculated using the equation hmax = (P0 - P)/ρg, where P0 is the atmospheric pressure, P is the pressure at point B, ρ is the density of the liquid, and g is the acceleration due to gravity.
 

Related to How Does a Siphon Work with Different Liquid Heights and Pressures?

What is fluid dynamics?

Fluid dynamics is the study of how fluids (liquids and gases) move and interact with each other and their surroundings. It involves analyzing the forces and pressures that affect fluid motion.

What is a siphon?

A siphon is a simple device used to transfer fluid from a higher level to a lower level without the use of a pump. It typically consists of a tube or hose that is bent in a U-shape and filled with fluid.

How does a siphon work?

A siphon works by creating a vacuum between the two ends of the tube, causing the fluid to flow from the higher end to the lower end. This vacuum is created by the weight of the fluid in the longer arm of the tube, which is greater than the weight of the fluid in the shorter arm.

What factors affect siphon flow?

The flow of a siphon is affected by several factors, such as the height difference between the two ends of the tube, the diameter of the tube, the density of the fluid, and the presence of any obstacles or bends in the tube.

Can a siphon work in a vacuum?

No, a siphon cannot work in a vacuum as it relies on atmospheric pressure to create the vacuum between the two ends of the tube. Without atmospheric pressure, there is no force to push the fluid from the higher end to the lower end.

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