[anita]

Hallo,

I created a mesh with blockMesh and m4.
Now I want to mirror the mesh at x-axis.
I used mirrorMesh. I worked, but the mesh points on the mirror plane are vanished. As result the cells on the mirror plane become bigger. Also checkMesh reacts strange.

Anita

original mesh:


mirrored mesh:



CheckMesh:

Exec : checkMesh . 2D
Date : Apr 07 2008
Time : 11:42:38
Host : st31
PID : 6301
Root : /home/kienzani/OpenFOAM/kienzani-1.4.1/run/ownTests/VortexVersuch1
Case : 2D
Nprocs : 1
Create time

Create polyMesh for time = constant

Time = constant

Mesh stats
points: 26366
edges: 65327
faces: 51852
internal faces: 25488
cells: 12890
boundary patches: 7
point zones: 0
face zones: 0
cell zones: 0

Number of cells of each type:
hexahedra: 12890
prisms: 0
wedges: 0
pyramids: 0
tet wedges: 0
tetrahedra: 0
polyhedra: 0

Checking topology...
Boundary definition OK.
Point usage OK.
Upper triangular ordering OK.
Topological cell zip-up check OK.
Face vertices OK.
Face-face connectivity OK.
Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces ...
Patch Faces Points Surface
inlet 65 132 ok (not multiply connected)
outlet 57 116 ok (not multiply connected)
outer 220 442 ok (not multiply connected)
body 52 106 ok (not multiply connected)
front 12890 13183 ok (not multiply connected)
backside 12890 13183 ok (not multiply connected)
mirror 190 384 ok (not multiply connected)

Checking geometry...
Domain bounding box: (-0.03 0 -0.0005) (0.12 0.03155 0.0005)
Boundary openness (-9.1555e-19 2.28887e-17 2.22228e-14) OK.
Max cell openness = 1.97984e-16 OK.
Max aspect ratio = 4.60698 OK.
Minumum face area = 1.30098e-07. Maximum face area = 2.14313e-06. Face area magnitudes OK.
Min volume = 1.30098e-10. Max volume = 1.17683e-09. Total volume = 4.4956e-06. Cell volumes OK.
Mesh non-orthogonality Max: 9.75454 average: 1.3819
Non-orthogonality check OK.
Face pyramids OK.
Max skewness = 0.159581 OK.
Min/max edge length = 0.000288467 0.00214313 OK.
All angles in faces OK.
Face flatness (1 = flat, 0 = butterfly) : average = 1 min = 1
All face flatness OK.

Mesh OK.

--> FOAM Warning :
From function polyMesh::readUpdateState polyMesh::readUpdate()
in file meshes/polyMesh/polyMeshIO.C at line 211
Number of patches has changed. This may have unexpected consequences. Proceed with care.
Time = 0

Mesh stats
points: 51722
edges: 128523
faces: 102888
internal faces: 51792
cells: 25780
boundary patches: 6
point zones: 0
face zones: 0
cell zones: 0

Number of cells of each type:
hexahedra: 25780
prisms: 0
wedges: 0
pyramids: 0
tet wedges: 0
tetrahedra: 0
polyhedra: 0

Checking topology...
Boundary definition OK.
Point usage OK.
***Faces not in upper triangular order.
<<Writing 1 unordered faces to set upperTriangularFace
Topological cell zip-up check OK.
Face vertices OK.
Number of identical duplicate faces (baffle faces): 617
Face-face connectivity OK.
Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces ...
Patch Faces Points Surface
inlet 128 258 ok (not multiply connected)
outlet 110 222 ok (not multiply connected)
outer 440 884 ok (not multiply connected)
body 98 196 ok (not multiply connected)
front 25160 25548 ok (not multiply connected)
backside 25160 25548 ok (not multiply connected)

Checking geometry...
Domain bounding box: (-0.03 -0.03155 -0.0005) (0.12 0.03155 0.0005)
Boundary openness (-2.09395e-18 3.87209e-17 6.31716e-14) OK.
***High aspect ratio cells found, Max aspect ratio: 3.2548e+193, number of cells 310
<<Writing 310 cells with high aspect ratio to set highAspectRatioCells
Minumum face area = 1.30098e-07. Maximum face area = 2.5e-06. Face area magnitudes OK.
Min volume = 2e-300. Max volume = 1.75e-09. Total volume = 9.0932e-06. Cell volumes OK.
Mesh non-orthogonality Max: 180 average: 14.5294
*Number of severely non-orthogonal faces: 362.
***Number of non-orthogonality errors: 813.
<<Writing 1175 non-orthogonal faces to set nonOrthoFaces
***Error in face pyramids: 1860 faces are incorrectly oriented.
<<Writing 1433 faces with incorrect orientation to set wrongOrientedFaces
#0 Foam::error::printStack(Foam:stream&) in "/home/kienzani/OpenFOAM/OpenFOAM-1.4.1/lib/linuxGccDPOpt/libOpenFOAM.so"
#1 Foam::sigFpe::sigFpeHandler(int) in "/home/kienzani/OpenFOAM/OpenFOAM-1.4.1/lib/linuxGccDPOpt/libOpenFOAM.so"
#2 Uninterpreted: [0xffffe420]
#3 Foam::primitiveMesh::checkFaceSkewness(bool, Foam::HashSet<int,> >*) const in "/home/kienzani/OpenFOAM/OpenFOAM-1.4.1/lib/linuxGccDPOpt/libOpenFOAM.so"
#4 Foam::checkGeometry(Foam::polyMesh const&, bool, bool) in "/home/kienzani/OpenFOAM/OpenFOAM-1.4.1/applications/bin/linuxGccDPOpt/checkMesh"
#5 main in "/home/kienzani/OpenFOAM/OpenFOAM-1.4.1/applications/bin/linuxGccDPOpt/checkMesh"
#6 __libc_start_main in "/lib/libc.so.6"
#7 Foam::regIOobject::readIfModified() in "/home/kienzani/OpenFOAM/OpenFOAM-1.4.1/applications/bin/linuxGccDPOpt/checkMesh"

[anita]

Problem solved !

I had to change planeTolerance in mirrorMeshDict from 1e-3 to 1e-4. Now the mesh looks good.

[nikhilmadduri]

hello,

where can we find this "mirrorMeshDict" file?

replies will be highly appreciated.

Thanks
Nikhil

[milleniumrider]

Hi,

I'm a novice with OpenFOAM and CFD in general. So any help would be appreciated.

I'm getting the same error when I run a checkMesh on my grid after using the makeAxialMesh utility. Can anyone shed some light on this?


Here is the output I get.


Create polyMesh for time = 0

Time = 0

Mesh stats
points: 882
internal points: 0
faces: 1640
internal faces: 760
cells: 400
boundary patches: 3
point zones: 0
face zones: 0
cell zones: 0

Overall number of cells of each type:
hexahedra: 400
prisms: 0
wedges: 0
pyramids: 0
tet wedges: 0
tetrahedra: 0
polyhedra: 0

Checking topology...
Boundary definition OK.
Point usage OK.
Upper triangular ordering OK.
Face vertices OK.
Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces ...
Patch Faces Points Surface topology
movingWall 20 42 ok (non-closed singly connected)
fixedWalls 60 122 ok (non-closed singly connected)
frontAndBack 800 882 ok (non-closed singly connected)

Checking geometry...
Overall domain bounding box (0 0 -0.005) (0.1 0.1 0.005)
Mesh (non-empty, non-wedge) directions (1 1 0)
Mesh (non-empty) directions (1 1 0)
All edges aligned with or perpendicular to non-empty directions.
Boundary openness (8.47033e-18 -8.47033e-18 -4.51751e-17) OK.
Max cell openness = 1.35525e-16 OK.
Max aspect ratio = 2 OK.
Minumum face area = 2.5e-05. Maximum face area = 5e-05. Face area magnitudes OK.
Min volume = 2.5e-07. Max volume = 2.5e-07. Total volume = 0.0001. Cell volumes OK.
Mesh non-orthogonality Max: 0 average: 0
Non-orthogonality check OK.
Face pyramids OK.
Max skewness = 1e-08 OK.

Mesh OK.

--> FOAM Warning :
From function polyMesh::readUpdateState polyMesh::readUpdate()
in file meshes/polyMesh/polyMeshIO.C at line 205
Number of patches has changed. This may have unexpected consequences. Proceed with care.
Time = 0.00125

[gschaider]

Originally Posted by milleniumrider

Hi,

I'm a novice with OpenFOAM and CFD in general. So any help would be appreciated.

I'm getting the same error when I run a checkMesh on my grid after using the makeAxialMesh utility. Can anyone shed some light on this?

Most mesh manipulation utilities write the changed mesh to the first time-step so that you don't accidentially overwrite a good mesh.

checkMesh assumes that the meshes at the different time-steps are from a moving mesh and should have the same set of patches.
makeAxialMesh violates that assumption, but if you don't get any other complaints the mesh should be OK (move it to constant/polyMesh and try it)

Bernhard