Water Tank Design: Pressure Calculation

AI Thread Summary
The pressure acting on the vertical wall of a cylindrical water tank can be calculated using the formula Pressure = Density * gravity * height, where height is measured from the water surface to the calculation point. When replacing water with dry sand, the situation differs as sand is not a fluid; factors like moisture content and grain size significantly influence pressure calculations. While the basic fluid equation may apply to static conditions, dynamic scenarios with flowing sand require different considerations, including stress concentration and fatigue strength. The discussion highlights the importance of understanding the nature of the material and its behavior under different conditions. Accurate pressure calculations are essential for effective tank design.
Su Solberg
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Hello, everyone.

I am trying to calculate the pressure acting at the vertical wall of a cylinder water tank.

I am wondering whether the presure acting on the wall is as follow:

Pressure = Density * gravity * height

where height is from the water surface to the calculation point.


Also, I am wondering whether the situation is the same when i replace the water with dry sand.

Thank you very much for your help.
 
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Su Solberg said:
Hello, everyone.

I am trying to calculate the pressure acting at the vertical wall of a cylinder water tank.

I am wondering whether the presure acting on the wall is as follow:

Pressure = Density * gravity * height

where height is from the water surface to the calculation point.

Yes.

Su Solberg said:
Also, I am wondering whether the situation is the same when i replace the water with dry sand.

I'm not 100% sure, but I believe it would essentially be the same given that the sand particles are very small and would probably give a pressure field equivalent to that of a liquid.

CS
 
the math is right for a fluid, but...
since sand is not actual fluid,
I don't know it the math for a fluid would work
(if I pour a bucket of sand on the floor, it won't disperse flat)
so that seems to tell me surface tension may be a factor, not sure
there may be other variables to consider, too

I am intrigued how to figure that

dr
 
Su Solberg said:
Also, I am wondering whether the situation is the same when i replace the water with dry sand.

I would bet that the equations for dry sand will be different, but I'm not a civil engineer. I know that it will depend heavily on moisture content, and probably grain size (or some measure of it's flow-ability).
 
Su Solberg said:
Hello, everyone.

I am trying to calculate the pressure acting at the vertical wall of a cylinder water tank.

I am wondering whether the presure acting on the wall is as follow:

Pressure = Density * gravity * height

where height is from the water surface to the calculation point.


Also, I am wondering whether the situation is the same when i replace the water with dry sand.

Thank you very much for your help.

depend on weather the pressure vessel has the fluid inside in it has static or dynamic in nature...

cause if the sand is continuesly coming in and going out of the vessel; then in that case the design will b different and very critical...in that case stress concentration will come in picture ... consider notch sensitivity factor and dynamic factor for fatigue strength...

if it is static .. then it will not affect a lot...design can b same as that of water...

i think...
 
The analogies are similar - see equation 8 w/9:

http://www.mec.utt.ro/~tm/SIPA_05/Part1/Ola2_G.pdf

If you have "flow" then things change as per that paper.
 
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