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-   -   BouyantFoam (http://www.cfd-online.com/Forums/openfoam-solving/59177-bouyantfoam.html)

antopnieta January 30, 2008 08:23

I'm new with OpenFoam and I ha
 
I'm new with OpenFoam and I have a question about BouyantFoam:

If fvSolution of BouyantFoam works with PISO, also i have to write rho, h, k, etc in SOLVERS?? If this not the case, where put this constants?

Thank!!

evan January 30, 2008 13:22

Hi Antonieta, You mis-spell
 
Hi Antonieta,

You mis-spelled Buoyant in your title. You might try here for some answers, as this title (correctly spelled) is already on the lists.

http://www.cfd-online.com/OpenFOAM_D...tml?1190235325

Briefly, you need to look at the solver. buoyantFoam uses the heatTransfer solver located here:

/applications/solvers/heatTransfer

So, even though I haven't used this solver before, I just look at buoyantFoam.C and createfields.H, and immediately see that rho and h are being declared through the thermophysicalmodels directory in the src directory; in particular, they are unknowns here that are beings solved, and not constants. If you want to see this in paraview, then I think you need to create an IOobject for, say, the enthalpy; which is not currently listed in createFields.H.

Anyway, I would recommend reading through a bunch of the discussion here, the user and programmers manual, and then take a look at the code for the solver. Things should start to become clearer at that point.

Hope this helps some.
Evan

antopnieta January 30, 2008 15:25

Dear Evan: Thank for your a
 
Dear Evan:

Thank for your answer!

First at all, yes, it's BuoyantFoam and not Bouyant.

Second... how I create an IOobject?? or where I find how create...

I read a lot about this, but there a lot of things that I don't understand yet, and this is one of them... for this reason I asked...

Thank again..

Antonieta

evan January 30, 2008 15:58

Maybe try to add in createfiel
 
Maybe try to add in createfield.H, for the h field for example, the following:

volScalarField h
(
IOobject
(
"h"
runTime.timeName(),
mesh,
IOobject::NO_READ,
IOobject::AUTO_WRITE
),
thermo->h()
);

remove the volScalarField& h assignment, recompile. and try the case again.

Evan

antopnieta January 30, 2008 16:32

Dear Evan: When I do that,
 
Dear Evan:

When I do that, I should see a new field h?? something happen when I do that?? Because all is the same...

Sorry for the basic questions but I never do this before...

Antonieta

evan January 31, 2008 15:42

Hi Antonieta, Not sure what
 
Hi Antonieta,

Not sure what to tell you right now. I think that should have worked. Are you sure the field isn't being written in your case file? I will try it here in the next couple days on the buoyantFoam tutorial to see if it works for me (sorry, I am a bit busy at the moment), but I have done this for other solvers without trouble.

You could also change the IOobject to mesh and MUST_READ, like explained here:

http://www.cfd-online.com/cgi-bin/Op...show.cgi?1/878

But then you might need to write a boundary condition for the field in the tutorial 0 time directory.

Good luck.
Evan

evan February 1, 2008 20:08

Antonieta, Yeah, sorry, so
 
Antonieta,

Yeah, sorry, so my suggestion didn't work; I just tried it myself. Tried a couple of other things, but to no avail. I'll keep at it, and let you know if I figure it out.

Evan

stefan February 4, 2008 08:20

Hi, I'm a new user of OpenFOAM
 
Hi, I'm a new user of OpenFOAM and I have a little problem.

I want create a room with a radiator. At first I use buoyantSimpleFoam ... but I think thats not the best Solver, because it is for steadystate. Therefore a try it with buoyantFoam. My problem is deltaT, because U should be 0. (deltaT=Co*dx/U) How I define deltaT?

thanks for your help!

antopnieta February 4, 2008 08:22

Evan: Thank... i tried othe
 
Evan:

Thank... i tried other things too, but i I haven't had success.

I hope you have luck..

Antonieta


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