Cyclic BC's: Possible face ordering problem? (Channel flow)
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Hello World.
I'm doing a rather complex mesh for channel flow using 36 blocks to get the appropriate mesh resultion at the walls. The mesh despriction itself is working brilliant, but when I try to set the cyclic boundary conditions I'm getting this error: Code:
face 1 area does not match neighbour 36 by 160% -- possible face ordering problem. I'm not sure what is meant by the "possible face ordering problem". |
Well, I simply forgot one patch (containing four vertices).
That solved the problem. Another question: Do the patches of in- and outflow have to be exactly opposite of each other? That would mean after the list of inflow-patches is finished, I have to start with the patch opposite of the very first one? |
creating cyclic boundary condition
Hi, I am having difficulty in creating cyclic boundary condition, I have done it this way:
1- I created a mesh in Gambit (Quarter of a cylinder) and I called the two planes symmetrya and symmetryb. and I set them to be symmetry for periodic bc. 2-set the writePrecision in system/controlDict to 12. 3-In the end of *.msh file I saw (0 "Cells:") (12 (0 1 5eb78 0)) (12 (2 1 5eb78 1 4)) (0 "Zones:") (45 (2 fluid fluid)()) (45 (3 mass-flow-inlet ariinlet2)()) (45 (4 symmetry symmetryb)()) (45 (5 symmetry symmetrya)()) (45 (6 pressure-outlet outlet)()) (45 (7 wall wall)()) (45 (8 mass-flow-inlet airinlet1)()) (45 (9 mass-flow-inlet fuelinlet)()) (45 (11 interior default-interior)()) I did not change anything here, and leave it as it is. 3-then I ran fluentMeshTofoam *.msh : Building boundary and internal patches. Creating patch 0 for zone: 3 start: 1 end: 25 type: mass-flow-inlet name: ariinlet2 Creating patch 1 for zone: 4 start: 26 end: 10345 type: symmetry name: symmetryb Creating patch 2 for zone: 5 start: 10346 end: 20665 type: symmetry name: symmetrya Creating patch 3 for zone: 6 start: 20666 end: 23898 type: pressure-outlet name: outlet Creating patch 4 for zone: 7 start: 23899 end: 34233 type: wall name: wall Creating patch 5 for zone: 8 start: 34234 end: 34263 type: mass-flow-inlet name: airinlet1 Creating patch 6 for zone: 9 start: 34264 end: 34306 type: mass-flow-inlet name: fuelinlet Creating patch 7 for zone: 11 start: 34307 end: 1181033 type: interior name: default-interior Adding new patch ariinlet2 of type patch as patch 0 Adding new patch symmetryb of type symmetryPlane as patch 1 Adding new patch symmetrya of type symmetryPlane as patch 2 Adding new patch outlet of type patch as patch 3 Adding new patch wall of type wall as patch 4 Adding new patch airinlet1 of type patch as patch 5 Adding new patch fuelinlet of type patch as patch 6 Patch default-interior is internal to the mesh and is not being added to the boundary. Default patch type set to empty Writing mesh... to "constant/polyMesh" done. End 4-It creates in the constant/polymesh ---> boundary : 7 ( ariinlet2 { type patch; nFaces 25; startFace 1146727; } symmetryb { type symmetryPlane; nFaces 10320; startFace 1146752; } symmetrya { type symmetryPlane; nFaces 10320; startFace 1157072; } outlet { type patch; nFaces 3233; startFace 1167392; } wall { type wall; nFaces 10335; startFace 1170625; } airinlet1 { type patch; nFaces 30; startFace 1180960; } fuelinlet { type patch; nFaces 43; startFace 1180990; } ) 5-then I define the createPatchDict in /system and within that I have: matchTolerance 1E-3; pointSync true; patches ( { name symmetrya; type cyclic; constructFrom patches; patches (symmetrya symmetryb); } ); 6-then I ran createPatch, this was the outcome: Create time Reading createPatchDict. Using relative tolerance 0.001 to match up faces and points Create polyMesh for time = 0 Moving faces from patch symmetrya to patch 2 Moving faces from patch symmetryb to patch 2 Doing topology modification to order faces. Synchronising points. Points changed by average:0 max:0 Removing patches with no faces in them. Removing empty patch symmetryb at position 1 Removing patches. Writing repatched mesh to 1 End 7-It creates a folder /1/polyMesh and within that: []$ ls boundary cellZones faces faceZones neighbour owner points pointZones 8-vi boundary : 6 ( ariinlet2 { type patch; nFaces 25; startFace 1146727; } symmetrya { type symmetryPlane; nFaces 20640; startFace 1146752; } outlet { type patch; nFaces 3233; startFace 1167392; } wall { type wall; nFaces 10335; startFace 1170625; } airinlet1 { type patch; nFaces 30; startFace 1180960; } fuelinlet { type patch; nFaces 43; startFace 1180990; } ) 8-I copy all the contents of this folder to constant/polymesh/ 9- I did changed the symmetryplane type now to cyclic for symmetrya 10-I did the simpleFoam and I received this error: Create time Create mesh for time = 0 face 0 area does not match neighbour 10320 by 21.8435% -- possible face ordering problem. patch:symmetrya my area:0.000277 neighbour area:0.000344925 matching tolerance:0.001 Mesh face:1146752 vertices:4((0 0 0.1123) (0.05 0 0.1123) (0.05 0 0.11784) (0 0 0.11784)) Neighbour face:1157072 vertices:4((0 0.043315 0) (0 0.0502135 0) (0.05 0.0502135 0) (0.05 0.043315 0)) Rerun with cyclic debug flag set for more information. From function cyclicPolyPatch::calcTransforms() in file meshes/polyMesh/polyPatches/constraint/cyclic/cyclicPolyPatch.C at line 150. FOAM exiting Can anyone help me with this problem? |
i need help too about this problem :(
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