Lame question on tank analysis

[jmex]

Hello all,

I am trying to understand the inputs here. Let's suppose I have a water tank at home which is made of plastic. It is filled with water. So I am confused with the inputs.
At first when I gave only hydrostatic pressure, the tank was safe. But when I added atmospheric pressure by applying pressure condition on internal surface by 14.59 psi, it was failing. So do I have to apply atmospheric condition? Is it true?

Thanks,
Jmex

https://about.me/jdmech

 

[TGS4]

And what pressure is acting on the outside of the tank???

 

[rickfischer51]

They are not equivalent. Hydrostatic pressure will vary linearly from zero at the surface to a max value at the deepest point. Atmospheric pressure will be constant on any surface to which it is applied. And to TGS4's comment, the hydrostatic pressure is absolute pressure, not gauge pressure.

Rick Fischer
Principal Engineer
Argonne National Laboratory

 

[jmex]

Thank you for your replies. I know that hydrostatic pressure will vary from surface to deepest point. That's why there is an option of hydrostatic pressure in ansys which is different from pressure. Now my question is, am i suppose to apply atmospheric pressure(14.6959 Psi) to all surface inside of the tank? The atm pressure 14.6959 Psi is absolute pressure.

https://about.me/jdmech

 

[TGS4]

If you add the atmospheric pressure the inside won't you also have to apply it to the outside? But, they will just cancel each other out, in which case you just use gauge pressure and zero on the outside? Unless the outside of your tank is in deep space?

 

[rickfischer51]

In deep space there would be no gravity, so he doesnt have to include the hydrostatic pressure

Rick Fischer
Principal Engineer
Argonne National Laboratory

 

[TGS4]

Touché