CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   OpenFOAM Running, Solving & CFD (http://www.cfd-online.com/Forums/openfoam-solving/)
-   -   beginner in adaptive mesh refinement (http://www.cfd-online.com/Forums/openfoam-solving/77964-beginner-adaptive-mesh-refinement.html)

aki_yafuji July 8, 2010 10:57

beginner in adaptive mesh refinement
 
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

KrisT July 9, 2010 04:47

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.

aki_yafuji July 9, 2010 13:39

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

KrisT July 9, 2010 14:20

Quote:

Originally Posted by aki_yafuji (Post 266638)
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).

idefix March 27, 2012 07:06

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

idefix May 23, 2012 11:17

has nobody an idea what it could mean?

I would be really happy to get some help

potentialFoam February 29, 2016 03:59

Vortex Refinement
 
Dear Foamers,

I have another question concerning the settings in the dynamicMeshDict-file. I would like to refine a tip vortex dynamically, so with the pimpleDyMFoam-solver.

As entry 'field' in dynamicMeshDict I would like to use something like Lambda2.
How can I tell the solver to calc this field?


All times are GMT -4. The time now is 01:01.