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beginner in adaptive mesh refinement

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Old   July 8, 2010, 10:57
Default beginner in adaptive mesh refinement
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yafuji aki
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Hi to everyone!
I am Aki, a beginner in OpenFOAM.

I am intrested in adaptive mesh refinement and I managed to find
"dynamicMeshDict" dictionary, but I am not sure how it works...
Would you tell me a condition of the refinement? The mesh is refined
automatically when the velocity (or the Courant number) exceeds a given value?

And, I am not sure coefficients in the dictionary...

constant/dynamicMeshDict
--------------------------------------
dynamicFvMesh dynamicRefineFvMesh;

dynamicRefineFvMeshCoeffs
{
refineInterval 1;
field alpha1;
lowerRefineLevel 0.001;
upperRefineLevel 0.999;
unrefineLevel 10;
nBufferLayers 1;
maxRefinement 2;
maxCells 200000;
correctFluxes
(
(
phi
U
)
);
dumpLevel true;
}
--------------------------------------

I have performed some tutorials, so I guess "maxRefinement" means the max
refinement number. But I cound only understand it. I can not understand
what "refineInterval" and "maxCells" mean. And what are "lowerRefineLevel"
and "upperRefineLevel"...?
I would be grateful if you could provide me the meanings of them.

Thanks in advance!

Aki
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Old   July 9, 2010, 04:47
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As far as I understand:

refineInterval - specifies how often (every n:th timestep) the grid should be refined.

maxCells - limits the number of cells, should never be greater than the given number, an approximate number.

lowerRefineLevel - grid gets refined if "alpha1" is lower than this value.

upperRefineLevel - grid gets refined if "alpha1" is bigger than this value.
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Old   July 9, 2010, 13:39
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yafuji aki
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Dear KrisT

Thank you very much for your help!
I have performed some tutorials by changing them.
May I ask one more question???
What is "correctFluxes" ? These values are corrected each time step?

Aki
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Old   July 9, 2010, 14:20
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Quote:
Originally Posted by aki_yafuji View Post
Dear KrisT

Thank you very much for your help!
I have performed some tutorials by changing them.
May I ask one more question???
What is "correctFluxes" ? These values are corrected each time step?

Aki
Not sure about this one. Something about fluxes to correct when refining (phi), and variable they can be ineterpolated from (U).
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Old   March 27, 2012, 07:06
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Hello,

I looked into the code and find following:
nBufferLayer: Number of layers between different refinement levels
I understand it in that way: nBufferLayer 1 means:
a cell, which was refined once, can only be a neighbour of a cell which is not refined or refined twice. But this cell canīt be a neighbour of a cell which is refined three times.

In a tutorial I found the definitoin for maxRefinement:
maxRefinement means the number of refinements that are allowed for one cell.

But does everybody know what "unrefineLevel" mean?

Thanks a lot

Last edited by idefix; April 3, 2012 at 02:39.
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Old   May 23, 2012, 11:17
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has nobody an idea what it could mean?

I would be really happy to get some help
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