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-   -   BCs to the outlet patch (filling a simple tank) (http://www.cfd-online.com/Forums/openfoam-pre-processing/97038-bcs-outlet-patch-filling-simple-tank.html)

Ternox February 7, 2012 13:55

BCs to the outlet patch (filling a simple tank)
 
1 Attachment(s)
Hello

Nice to create my first post on the CFD-online forum !

I have been trying for 3 days to solve a very basic problem with openFoam/interFoam solver... a filling of a tank with steel water!
When I look at the results with paraFoam, from the step 90 to 100 the filling seems stopping and begin to be turbulent. The result is that the tank is not full of water but just filled at 90%.

I guess the air is trapped into the tank and It can't go out.
>>> Does anyone know which BCs should I apply to the outlet patch to allow the air to go throught and to fill completely ?

Please find attached my complete case ready to run !

Many thanks by advance,
All the best,
Pierre

Ternox February 8, 2012 03:37

Hello,

It seems you have to delete/move the text document named " Pb description " from the folder to run comfortly the simulation.

Sorry for this additional step,
And thank you for the hits you are going to give me.

All the best,
Pierre

Ternox February 10, 2012 05:33

Hello everybody,

In order to help you answering my question, I propose a synthesis of my BCs.

My problem is that the filling (steady flow from the bottom to the top) of a tank is not full, near to the outlet, the air seems to be trapped and not able to espace throught the outlet.

I am looking for the right BC for the outlet BC.


BC
--

같같같같같같같같inlet같같같같같같 walls같같같같같같같 outlet

boundary | 같같컋atch같같같같같같컋atch같같같같같같같patch

alpha1 같| 같같fixedValue같같컕eroGradient같같같같 zeroGradient
같같같같같같같같uniform 0

U같같같같 |같컀ixedValue같같같컀ixedValue같같같같같컕eroGrad ient
같같같같같컐niform (0 0 0.1)같컐niform (0 0 0)

p_rhg같같|같 zeroGradient같같같 zeroGradient 같같*** see bellow



***
outlet_mesh
{
type totalPressure;
p0 uniform 0;
U U;
phi phi;
rho rho;
psi none;
gamma 0.5;
value uniform 0;
}


Many thanks by advanced !
Pierre

Ternox February 17, 2012 11:21

1 Attachment(s)
Hello!

After a two weeks searching, here is my answer.

Place an outlet velocity to make the air escape. Moreover, as described in the "dambreack" tutorial, it is possible to usea bouyantPressure and an pressureInletOutletVelocity.

The limit of this solution is the inlet keeps on injecting fluid while the said fluid doen't run-over.

All the best,
Pierre


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