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Fan type BC in OF15

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Old   September 15, 2010, 07:56
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Olivier
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Hello Maddalena,

Thanks for this test case.

Have you tested to comment the line
Code:
//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
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Old   September 15, 2010, 08:03
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Hi,
Quote:
Originally Posted by olivierG View Post
Have you tested to comment the line
Code:
//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...
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Old   September 16, 2010, 06:04
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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:
Code:
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
Attached Images
File Type: jpg fan_0.jpg (34.2 KB, 96 views)
File Type: jpg fan_75.jpg (32.1 KB, 96 views)

Last edited by maddalena; September 16, 2010 at 06:07. Reason: added info
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Old   September 17, 2010, 08:21
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Quote:
Originally Posted by maddalena View Post
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
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Old   February 3, 2011, 11:57
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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!
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Old   February 9, 2011, 14:48
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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
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Old   August 24, 2011, 12:56
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Hi All,

I kindly ask You to read my thread type FAN OpenFOAM1.7.1.

Thank You in advance,

Claudio
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Old   November 9, 2011, 15:31
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Quote:
Originally Posted by maddalena View Post
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
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Old   November 10, 2011, 03:56
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Hello,
Quote:
Originally Posted by Curico View Post
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 fanPressure BC thread.
maddalena.
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Old   November 10, 2011, 08:30
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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

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Old   November 10, 2011, 08:33
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Hi Cesar
Quote:
Originally Posted by Curico View Post
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/ ?
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Old   July 30, 2015, 12:22
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Hello

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

Last edited by leinad; July 30, 2015 at 13:50.
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