Problem with cyclic boundaries in Openfoam 2.3, mesh import from ICEM
Dear Foamers,
have a really annoying problem concerning cylic boundaries imported from ICEM. When I use the createPatch command. This is what I get after using createPatch utility: Code:
--> FOAM FATAL ERROR: Code:
/*--------------------------------*- C++ -*----------------------------------*\ Code:
/*--------------------------------*- C++ -*----------------------------------*\ Thank you so much for your help. Best wishes, Scabbard |
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Thank you for your help. I use the structure mesh, and have checked in ICEM. I think both face could be perfectly cyclic. For my case, it is a flow past a cylinder and I want to let the front&back be cyclic. Here is my mesh: https://drive.google.com/file/d/0B1v...it?usp=sharing Could you help me to check where is the error? This problem annoying me for more than a week... Best wishes, Scabbard |
Hi Scabbard,
The file you shared only has got the mesh. Unfortunately I don't have the time to create a case just to debug your mesh :(. If you study the file I mentioned in the previous post, you'll see where the "tolerance" settings have to be placed in "createPatchDict". Best regards, Bruno |
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Sorry to trouble you. I have added the matchTolerance in my createPatchDict and set up 5 values from 1e-04 to 2e-02, but still got the same error... This make me crazy... https://drive.google.com/file/d/0B1v8BP1BA6NQTUJQYW9SU2VpUkE/edit?usp=sharing Here is my whole case. If it is convenient for you, could you help me to check it? Thank you so much for your help. Best wishes, Scabbard |
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Hi Scabbard,
Thanks, that makes it easier! OK, OpenFOAM has been trying to tell you that the patches do not perfectly match. As you can see in the attached image, the patches do not perfectly match up, because even though the face count is identical, their relative locations are not identical. The part on the left is the bottom patch and on the right is the top patch. As I wrote before, if "cyclic" patches don't work, you'll have to rely on "cyclicAMI" patches, which will assign weights to the corresponding faces on the other patch, even if the faces are completely different. Note that the "cyclicAMI" will not try to match up the faces directly, it will look at the location of each face and check what faces are on the other side at the same relative location. Best regards, Bruno |
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Thank you so much for your help. I will have a try to use cyclicAMI. However, do you know what cause the mesh changed in openFoam? Because when I check in ICEM, it seems to be the same both side around cylinder. Best wishes, Scabbard |
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My guess is that since you're not comparing directly one patch on top of the other on ICEM, then the mesh only looks like it's the same. |
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Dear Bruno, Thank you for you help. Best wishes, Scabbard |
createPatchDict
Dear Bruno
I am also running with the same problem as mentioned by Scaabard, i placed the createPatchDict file in system folder, but the error remains same face 0 area does not match neighbour by 136.618% -- possible face ordering problem. patch:cyclic-6_half0 my area:5.18008e-06 neighbour area:2.75111e-05 matching tolerance:0.0001 Mesh face:6687680 fc:(-0.494029 0.603639 0.00271732) Neighbour fc:(-0.494029 0.904544 0.00271732) If you are certain your matching is correct you can increase the 'matchTolerance' setting in the patch dictionary in the boundary file. Rerun with cyclic debug flag set for more information. From function cyclicPolyPatch::calcTransforms() in file meshes/polyMesh/polyPatches/constraint/cyclic/cyclicPolyPatch.C at line 220. |
Greetings Zahid,
:confused: I'm not a magician nor a hacker :rolleyes: So please don't expect me to just guess the reason why you're getting that error message. So, please provide more information, according to the guidelines given on this thread: http://www.cfd-online.com/Forums/ope...-get-help.html In addition:
Bruno |
Hello,
I encountered the same problem and I could solve it by defining rotational periodicity and then by declaring the corresponding vertices in ICEM as periodic. Then Right Click on Faces in the Blocking tree -> Periodic Faces -> ensure that really every periodic face is colored accordingly. createPatch went fine after this procedure. |
Hello Bruno,
i have a similar issue, i get the following error message: Code:
parallels@ubuntu:~/OpenFOAM/OpenFOAM-3.0.x/chtMRF$ splitMeshRegions -cellZones -overwrite please help, i don't know what exactly to do to fix it, i have tried both ciclic and cyclicAMI patch type, i have also changed my match tolerance i still get the same error. please help. kind regards |
Quick answer: I haven't managed to look into the case, but I suggest that you only convert the patches to "cyclic" or "cyclicAMI" after you've ran splitMeshRegions, not before.
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Hi All,
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I have made a 3D mesh in ICEM for an Airfoil and transferd into openfoam, used snappyhexMesh to put the airfoil inside the mesh and did meshing.
I just wanted to change the symmetry patches the front and back of the airfoil into cyclicAMI patches to have a effects of a long airfoil and did it sucessfully, the simulation works my question is what should be my seperationVector (0 0 0); ???in the boundary file, the thickness of my domain is 0.027m, when I have Code:
SYM when I have SYM (0 0 0.027) and SYM1 (0 0 -0.027) the simulation starts works till 525 and then crashes due to time step continuity error can some one please tell me whats seperationVector ? and what should it it be for such simple airfoil case where the SYM patch actual coordinates are (0 0 0) and SYM1 coordinates in the geometry are (0 0 0.027) or maybe my BC is the reason I have also attached my U and P BC |
separationVector
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How do you know what is your separationVector Can you please Explain, I have been trying to do Transitional Peridocity for an airfoil in the spanwise direction and failing miserably, futher explained in this post http://www.cfd-online.com/Forums/ope...tml#post582845 Regards, Hasan K.J [ Moderator note: This post and the one below were moved from this other thread: http://www.cfd-online.com/Forums/ope...-parallel.html ] |
Cyclic boundary
In your example, the correct setting should be :
Code:
cyclic0 Best wishes J-Michel |
I would just like to make use of the excellent advice in this thread to ask if anyone has had the following problem:
creating cyclics works fine using createPatch on my mesh. However, in a different case, I first merge the aforementioned mesh with another (rotor stator meshes) using mergeMeshes, and then run createPatch in an attempt to create cyclics (on the same patches as before) but now I get the face ordering error! What can be wrong? Does merge meshes change the ordering of the faces of my patches? I experimented around and cyclicAMI doesnt produce any error, but I am worried about using cyclicAMI because the mesh periodic patches should be identical (they come from turbogrid). Is there any harm using cyclicAMI? |
sector of cylinder
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hello guys
is it possible to define "cyclic" or "cyclicAMI" boundary condition for faces "A" and "B" in bellow figure? thanks for your replies. |
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