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Single Rotating Frame with MRFSimpleFoam

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Old   May 16, 2008, 11:08
Default Hi everybody! I'm trying to
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David Hora
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Hi everybody!

I'm trying to simulate a modified version of the mixerVessel2D case with MRFSimpleFoam. The stator should rotate with the same angular velocity as the rotor. For this reason I assigned all the cells to the cellZone rotor by modifying blockMeshDict.m4. I also modified constant/MRFZones so that the patch stator is rotating too.

Unfortunately I'm getting pretty high velocities and I don't know why.



Here are the modified files:

blockMeshDict.m4
MRFZones

Is it possible at all to simulate a Single Rotating Frame with MRFSimpleFoam or did I make a mistake? Any help would be really appreciated.

Regards
David
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Old   May 19, 2008, 05:51
Default I forgot to say that I'm using
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I forgot to say that I'm using a value of 314.157 for omega. The highest velocity should be around 31.5 m/s and not 60 m/s. Any ideas?

Thanks
David
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Old   May 19, 2008, 09:34
Default Ok, sorry guys. I found the pr
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Ok, sorry guys. I found the problem. It was my mistake ;-)
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Old   May 19, 2008, 10:06
Default Hi David, I just tried a simi
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Hi David,
I just tried a similar case with yours and it works (omega =104.72 rad/s; radius = 0.514 m -> v = 53 m/s):


Dragos
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Old   May 20, 2008, 08:21
Default Hi Dragos Thank you very mu
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Hi Dragos

Thank you very much for helping me. Unfortunately I can't understand why it worked with your case while it didn't work with my case??

My problem was that I didn't set up the case correctly. I found two different solutions for my problem:

Solution 1:
- Assign all the cells to cellZone rotor in blockMeshDict.m4
- Move the faces from patch stator to patch rotor and delete patch stator in blockMeshDict.m4

Solution 2:
- Assign the rest of the cells to cellZone stator.
- Modify makeMesh and the dict-files so that all the operations are made for rotor & stator.
- Change MRFZones in the following way:

2
(
rotor
{
patches (rotor);
origin origin [0 1 0 0 0 0 0] (0 0 0);
axis axis [0 0 0 0 0 0 0] (0 0 1);
omega omega [0 0 -1 0 0 0 0] 314.159;
}

stator
{
patches (stator);
origin origin [0 1 0 0 0 0 0] (0 0 0);
axis axis [0 0 0 0 0 0 0] (0 0 1);
omega omega [0 0 -1 0 0 0 0] 314.159;
}
)

Regards
David
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Old   May 20, 2008, 09:58
Default Solution 1b: - Assign all the
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Solution 1b:
- Assign all the cells to cellZone rotor in blockMeshDict.m4
- Change MRFZones in the following way:

1
(
rotor
{
patches (rotor stator);
origin origin [0 1 0 0 0 0 0] (0 0 0);
axis axis [0 0 0 0 0 0 0] (0 0 1);
omega omega [0 0 -1 0 0 0 0] 314.159;
}
)
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Old   May 20, 2008, 10:04
Default Hello David, From what I unde
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Hello David,
From what I understand, you want to rotate everything, so you should assign all the cells to the rotor.
Basically, you are after a rotating rigid body solution.

Dragos
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Old   May 22, 2008, 04:25
Default Hi Dragos That is exactly w
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Hi Dragos

That is exactly what I wanted to do. My intention was to play with a simple case to understand it. Now I'm trying to simulate a pump impeller.

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David
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