[olivierG]

Hello Maddalena,

Thanks for this test case.

Have you tested to comment the line

//jump_ = max(jump_, scalar(0));

in fanFvPatchFields.C ?
As Mike pointed out, this is the only difference between 1.5-dev and 1.6.x/1.7.x

Olivier

[maddalena]

Hi,

Originally Posted by olivierG

Have you tested to comment the line

//jump_ = max(jump_, scalar(0));

in fanFvPatchFields.C ?

no, I did not tried. However, if it has been added for stability reason, I think it is a good idea to not modify it, and define patches properly...

[maddalena]

One more question on the subject.
I am experiencing hard time to simulate a closed loop cooling system which includes a fan. I set the fan direction as described above: choose the master and slave face as I want the air moves and set the f coefficient as 1(10). PotentialFoam confirms that my settings are OK, as shown in fan_0.png. However, when using simpleFoam (with turbulence off), the flow reverses its direction and, at time 75, it is completely on the opposite direction I want it to go, see fan_75.png.
I also noticed that the continuity error is a little bit too high: at time 75 I have:

time step continuity errors : sum local = 0.0232117, global = -9.05912e-06, cumulative = -9.81427e-05

This let me think that I have some problems with BC, and since all the other domains are walls or standard cyclic, I lay on the idea that I still miss something on the fan BC.
Any ideas on the reason of that?

thank you for any idea or suggestion.

mad

[maddalena]

Originally Posted by maddalena

I still miss something on the fan BC.

For everyone that will meet the same problem: the fan BC is very sensitive to the mesh quality in proximity of it. Although having a good tet mesh, the simulation never converged. The solution was to use a hexa mesh in the proximity of the fan.
Hope this help someone.

mad

[J.Randall]

Hi all,

I'm using the fan bc, which is proving very useful for me. However I was wondering given the case where the velocity varies across the boundary condition which value of V is used to calculate the pressure drop (given the inputted polynomial coefficients). Is it an average value?

Thanks for your help!

[maddalena]

Hello,
It seems like that problems I thought solved reappears suddenly in these days…
As usual, velocity field at the fan interface looks unrealistic: wiggles and vectors going in the wrong direction. However:

1. f coefficient is positive:1(10) -> why? see here
2. I have got hexa mesh at the fan interface -> why? see here;
3. Flow direction is ok according to potentialFoam and to the first time step of the simulation;
4. Domains and blocks are on order -> applies to pointwise-openfoam export, see here.

Any idea of what is happening over here? I have spent 9 hours today trying to understand what is going wrong, without success. Suggestions?

mad

[claco]

Hi All,

I kindly ask You to read my thread http://www.cfd-online.com/Forums/ope...am1-7-1-a.html.

Thank You in advance,

Claudio

[Curico]

Originally Posted by maddalena

Hello Steinar,
could you explain me how I set the sign of pressure difference? How can I understand if I have to set the delta p is positive or negative before running the case itself? Thank you!

hello everyone

I'm new to the use of OpenFOAM, I have installed on my computer OpenFOAM 2.0.1, and I'm trying to model a bedroom with a fan in the center, the flow enters through a window and out through a door. Download the example of the fan, the compiler creates in the boundary conditions and fan_half1 fan_half0 patches and not that I give these values ​​in the file 0 / p

would greatly appreciate your answers
cordially
Cesar

[maddalena]

Hello,

Originally Posted by Curico

I'm new to the use of OpenFOAM, I have installed on my computer OpenFOAM 2.0.1

starting from Openfoam 2.0.0, a new BC has been implemented in OpenFOAM, see http://www.cfd-online.com/Forums/ope...essure-bc.html thread.
maddalena.

[Curico]

thank you very much Maddalena

If anyone could help me more, they are most grateful.

I have also problems with the creation of the mesh in OpenFOAM, I can not define the inner patch to model the fan, try making a mesh of ideas, but when using the tool converts the mesh buts ideasUnvToFoam lose some volume elements, could you help me again by favor.

thanks

Cesar.

[maddalena]

Hi Cesar

Originally Posted by Curico

but when using the tool converts the mesh buts ideasUnvToFoam lose some volume elements

I am sorry but I have no experience on the subject. Why do not you open a new thread here: http://www.cfd-online.com/Forums/openfoam-meshing/ ?
mad

[leinad]

Hello

I wanted to run this case posted above"fan.tar.gz"