|
[Sponsors] |
July 8, 2010, 10:57 |
beginner in adaptive mesh refinement
|
#1 |
New Member
yafuji aki
Join Date: Jul 2010
Location: Japan
Posts: 14
Rep Power: 16 |
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 |
|
July 9, 2010, 04:47 |
|
#2 |
Member
Join Date: May 2009
Posts: 32
Rep Power: 17 |
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. |
|
July 9, 2010, 13:39 |
|
#3 |
New Member
yafuji aki
Join Date: Jul 2010
Location: Japan
Posts: 14
Rep Power: 16 |
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 |
|
July 9, 2010, 14:20 |
|
#4 |
Member
Join Date: May 2009
Posts: 32
Rep Power: 17 |
Not sure about this one. Something about fluxes to correct when refining (phi), and variable they can be ineterpolated from (U).
|
|
March 27, 2012, 07:06 |
|
#5 |
Member
Join Date: Aug 2011
Posts: 89
Rep Power: 15 |
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. |
|
May 23, 2012, 11:17 |
|
#6 |
Member
Join Date: Aug 2011
Posts: 89
Rep Power: 15 |
has nobody an idea what it could mean?
I would be really happy to get some help |
|
February 29, 2016, 02:59 |
Vortex Refinement
|
#7 |
Member
Peter
Join Date: Nov 2015
Location: Hamburg, Germany
Posts: 57
Rep Power: 10 |
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? |
|
August 1, 2016, 09:08 |
|
#8 |
Member
Peter
Join Date: Nov 2015
Location: Hamburg, Germany
Posts: 57
Rep Power: 10 |
Finally, I programmed a new solver based on pimpleDyMFoam. There, I calculated the nedded scalar field (like Lambda2). In constant/dynamicMeshDict I specify the variables that prescribe the refinement and so it works
|
|
August 28, 2016, 22:20 |
|
#9 | |
Member
Francis
Join Date: Jan 2014
Location: Toronto
Posts: 50
Rep Power: 12 |
Quote:
Is this new solver working with dynamicRefineFvMesh in 2D ? |
||
August 29, 2016, 03:03 |
|
#10 |
Member
Peter
Join Date: Nov 2015
Location: Hamburg, Germany
Posts: 57
Rep Power: 10 |
Hi Francis,
what do you mean with 'dynamicRefineFvMesh'? I didn't try but I think it should work in 2D - why not? Regards, Peter |
|
August 29, 2016, 06:54 |
|
#11 |
Member
OpenCFD
Join Date: Mar 2009
Posts: 68
Rep Power: 19 |
The dynamic refinement is cutting cells 2x2x2 - in all directions, so you would create mesh cells in directions you are not solving for. Which would be not such a problem, but you are creating also non-orthogonality and you will have parasitic fluxes in the direction you are not solving for and your solution is loosing precision at least.
|
|
August 29, 2016, 06:57 |
|
#12 |
Member
Peter
Join Date: Nov 2015
Location: Hamburg, Germany
Posts: 57
Rep Power: 10 |
Thanks! That's correct. So it works, but not in the desired way.
|
|
July 15, 2019, 06:27 |
|
#13 |
Senior Member
krishna kant
Join Date: Feb 2016
Location: Hyderabad, India
Posts: 133
Rep Power: 10 |
Hi Everyone,
Isn't there any way to control the division of cells in 2D ? or Isn't there any way to make the division orthogonal always ? |
|
May 7, 2020, 03:49 |
|
#14 |
Member
Join Date: Mar 2015
Posts: 36
Rep Power: 11 |
Does it mean, that the actual implementation of dynamicMeshRefinement can only deal with hexahedra cells?
That would mean it is useless if I have tetrahedras in my mesh? |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Gambit problems | Althea | FLUENT | 22 | January 4, 2017 03:19 |
[snappyHexMesh] SnappyHexMesh for internal Flow | vishwa | OpenFOAM Meshing & Mesh Conversion | 24 | June 27, 2016 08:54 |
Moving mesh | Niklas Wikstrom (Wikstrom) | OpenFOAM Running, Solving & CFD | 122 | June 15, 2014 06:20 |
[mesh manipulation] local mesh refinement at channel geometries | Kr_kim | OpenFOAM Meshing & Mesh Conversion | 6 | February 9, 2010 14:25 |
basic of mesh refinement | arya | CFX | 4 | June 19, 2007 12:21 |