# Water Tank Design

1. Feb 22, 2010

### Su Solberg

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.

2. Feb 22, 2010

### stewartcs

Yes.

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

3. Feb 23, 2010

### dr dodge

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

4. Feb 23, 2010

### Mech_Engineer

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).

5. Feb 25, 2010

### vishal badal

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....

6. Feb 26, 2010

### Canadieng

Last edited by a moderator: Apr 24, 2017
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