[lasb]

Hi,

I am trying to use the simpleBouyantFoam solver with inlets and outlets.

The problem is that it is complaining over a continuity error in the outflow.

--> FOAM FATAL ERROR : Continuity error cannot be removed by adjusting the outflow.

Please check the velocity boundary conditions and/or run potentialFoam to initialise the outflow.

Total flux : 76.8043
Specified mass inflow : 10.4276
Specified mass outflow : 0
Adjustable mass outflow : 1.17153e-16


From function adjustPhi(surfaceScalarField& phi, const volVectorField& U,const volScalarField& p
in file cfdTools/general/adjustPhi/adjustPhi.C at line 111.

FOAM exiting

So I tried to look at my boundaryconditions. They seem fine. Then I looked at potentialFoam. My problem is that if I want to initialise the outflow. p is calculated as p/rho. That is: the dimensions for p are not the same in potentialFoam as they are in bouyantSimpleFoam.

If someone has any ideas how to solve/omit this problem I would be very happy.

Best Regards,
Lasse

[hjasak]

Yes: take the same geometry, solve potential flow separately and copy ONLY the velocity field.

Alternatively (I take it you've got zeroGradient on U at outlet), set the initial field to something that is non-zero and try again.

Please let me know what happens, I'm interested if I'm guessing right.

Hrv

[lasb]

Hi,

Thanks for replying so fast.

You were right. If I run potentialFoam and then copy the velocity field and run it with buoyantSimpleFoam it works. But it can only run for a limited amount of time, then it says:

--> FOAM FATAL ERROR : Maximum number of iterations exceeded

I can see that it is crashing trying to calculate pd. I'm not sure how to solve this.

Any ideas?

Lasse

[hjasak]

The solver itself is not limited in any way: there is no question of the solver running to a limited amount of time or any similar dishonesty.

I bet it is failing when trying to calculate some material properties as a function of temperature and pressure using Janaf. Try using constant material properties - it should run without trouble. Onc eyou get that sorted out, switch back to Janaf and see what happens.

Enjoy,

Hrv

[lasb]

Thanks, I bet you're right.

I'm still learning OpenFOAM and has no idea where I can find material properties nor how to switch them on and off. Where do I do that?

I don't know what Janaf is, but I guess it's not that important.

Sorry for my stupid questions.

Lasse

[WernerW]

Hi !!

could you please explain with more details how do you run potentialFoam separately and introduce that to my actual model? I'm trying to do this creating a new folder and trying to make my model as similar as posible to the tutorial potentialFoam/pitzDaily. So far I had some results as you can see in the image.

How do I Insert the results of the simulation in my actual model ? Where are these results ? It seems as if they are are saved in the files of folder 0 because files U, P and Phi are very heavy.

Originally Posted by lasb

Hi,

Thanks for replying so fast.

You were right. If I run potentialFoam and then copy the velocity field and run it with buoyantSimpleFoam it works. But it can only run for a limited amount of time, then it says:

--> FOAM FATAL ERROR : Maximum number of iterations exceeded

I can see that it is crashing trying to calculate pd. I'm not sure how to solve this.

Any ideas?

Lasse

Lasse, Do you run the simulation for than one step?a Can you make an unsteady potentialFoam simulation ?

thank you in advance for any help or interest .

regards,
Werner

p.s. If you are curious why I started trying this please check my other reply in "Initializing with PotentialFoam" http://www.cfd-online.com/Forums/ope...tml#post561363.