[julieng]

Hello,


I want to do again the same simple 2D case that (solver chtMultiRegionSimpleFoam)

ChtMultiRegion changeDirectory


But I want to be able to mesh my next cases in a simple way. I had a look on snappyHexMesh with CHT problems and it seems very difficult to do.

So I try a more direct way with Salome. I reproduce the exact geometry and exact mesh with salome that created with blockMesh (see picture)



I have done the following:
- create geometry 2D (2 fluids 1 solid)
- I have mesh each 2D domain

- I have extrude the 2D meshes into to 3D with 1 cell thick (a long way to get the boundary groups, but it works)
- All boundaries are defined in groups (inlet, boundaries between domains, outlets...)
- I made a compound mesh with the 3 domains meshes. (I remove all the vertex, edge and volume groups created by default, keeping only the surface groups).
- I have a folder case (see picture)
- I run the command
"ideasUnvToFoam Mesh_compound.unv"


With the log resulting seems ok:



Of 51050 so-called boundary faces 200 belong to two cells and are therefore internal
Sorting boundary faces according to group (patch)
0: minXplate_extruded is patch
1: plate_to_botAir_extruded is faceZone
2: plate_to_topAir_extruded is faceZone
3: maXplate_extruded is patch
4: top_bottom_plate is patch
5: inlet_botAir_extruded is patch
6: minZ_botAir_extruded is patch
7: outlet_botAir_extruded is patch
8: botAir_to_plate_extruded is faceZone
9: top_bottom_botAir is patch
10: inlet_topAir_extruded is patch
11: topAir_to_plate_extruded is faceZone
12: maxZ_topAir_extruded is patch
13: outlet_topAir_extruded is patch
14: top_bottom_topAir is patch

Constructing mesh with non-default patches of size:
minXplate_extruded 50
maXplate_extruded 100
top_bottom_plate 10100
inlet_botAir_extruded 100
minZ_botAir_extruded 100
outlet_botAir_extruded 100
top_bottom_botAir 20000
inlet_topAir_extruded 100
maxZ_topAir_extruded 100
outlet_topAir_extruded 100
top_bottom_topAir 20000

Adding cell and face zones
Face Zone botAir_to_plate_extruded 100
Face Zone topAir_to_plate_extruded 100
Face Zone plate_to_botAir_extruded 100
Face Zone plate_to_topAir_extruded 100

End



It creates a polyMesh folder in constant/



- The next step is the command
"splitMeshRegions -cellZones -overwrite"



Number of regions:1



The log result is:


Writing region per cell file (for manual decomposition) to "C:/PROGRA~1/BLUECF~1/OFUSER~1/run/CHT_1solid_salomeCopie/constant/cellToRegion"

Writing region per cell as volScalarField to "C:/PROGRA~1/BLUECF~1/OFUSER~1/run/CHT_1solid_salomeCopie/0/cellToRegion"

Region Cells
------ -----
0 25050

Region Zone Name
------ ---- ----
0 -1 domain0

Sizes of interfaces between regions:

Interface Region Region Faces
--------- ------ ------ -----

Reading volScalarField cellToRegion

Only one region. Doing nothing.
End



- What is the problem ?



Best regards

[julieng]

I found that I need also the add the domains in mesh groups, and after running
"splitMeshRegions -cellZones -overwrite" I have all the domains and boundaries well defined. The command checkMesh gives no warning.



I run also the command

transformPoints -scale '(0.001 0.001 0.001)'
to convert into meter my mesh coming from Salome.


I start the chtMultiRegionSimpleFoam calculation, it runs the first 152 iterations and it crashes. I have keep all the BC and fvScheme et fvSolutions than my first case created with blockMesh.


The error when it crashs is:


Time = 152


Solving for fluid region GrbotAir_Volumes
DILUPBiCG: Solving for Ux, Initial residual = 0.382244511, Final residual = 0.000484013494, No Iterations 3
DILUPBiCG: Solving for Uz, Initial residual = 0.335275599, Final residual = 0.000504403178, No Iterations 3
DILUPBiCG: Solving for h, Initial residual = 1, Final residual = 0.0897453108, No Iterations 3
Min/max T:400 500
DICPCG: Solving for p_rgh, Initial residual = 0.521602535, Final residual = 0.0514694741, No Iterations 8
DICPCG: Solving for p_rgh, Initial residual = 0.0243979882, Final residual = 0.00205952534, No Iterations 34
DICPCG: Solving for p_rgh, Initial residual = 0.00077404709, Final residual = 6.74546295e-005, No Iterations 43
time step continuity errors : sum local = 1.27416883e+023, global = 1.3403119e+021, cumulative = -1.48069445e+049
Min/max rho:0.2 2

Solving for fluid region GrtopAir_Volumes
DILUPBiCG: Solving for Ux, Initial residual = 0.999914293, Final residual = 4.50959413e-010, No Iterations 3
DILUPBiCG: Solving for Uz, Initial residual = 0.999914293, Final residual = 8.33926922e-010, No Iterations 3
Generating stack trace...


Backtrace:
ZN10StackTraceC1Ev [0x705c1465+0x25]
module: C:\PROGRA~1\BLUECF~1\ThirdParty-5.x\platforms\mingw_w64GccDPInt32\lib\libstack_tra ce.dll
ZN4Foam5error10printStackERNS_7OstreamE [0x1201c88+0x218]
module: C:\PROGRA~1\BLUECF~1\OpenFOAM-5.x\platforms\mingw_w64GccDPInt32Opt\lib\libOpenFO AM.dll
ZN4Foam6sigFpe13sigFpeHandlerEi [0x1202af3+0x33]
module: C:\PROGRA~1\BLUECF~1\OpenFOAM-5.x\platforms\mingw_w64GccDPInt32Opt\lib\libOpenFO AM.dll
(No symbol) [0x40468d]
module: C:\PROGRA~1\BLUECF~1\OpenFOAM-5.x\platforms\mingw_w64GccDPInt32Opt\bin\chtMultiR egionSimpleFoam.exe
_C_specific_handler [0x7ff8c9bf7c58+0x98]
module: C:\WINDOWS\System32\msvcrt.dll
0_chkstk [0x7ff8cc7df7dd+0x11d]
module: C:\WINDOWS\SYSTEM32\ntdll.dll
RtlWalkFrameChain [0x7ff8cc74d856+0x13f6]
module: C:\WINDOWS\SYSTEM32\ntdll.dll
KiUserExceptionDispatcher [0x7ff8cc7de70e+0x2e]
module: C:\WINDOWS\SYSTEM32\ntdll.dll
ZN4Foam7sumProdIdEEdRKNS_5UListIT_EES5_ [0x11a7deb+0x2b]
module: C:\PROGRA~1\BLUECF~1\OpenFOAM-5.x\platforms\mingw_w64GccDPInt32Opt\lib\libOpenFO AM.dll
ZN4Foam8gSumProdIdEEdRKNS_5UListIT_EES5_i [0x12e830d+0xd]
module: C:\PROGRA~1\BLUECF~1\OpenFOAM-5.x\platforms\mingw_w64GccDPInt32Opt\lib\libOpenFO AM.dll
ZNK4Foam5PBiCG5solveERNS_5FieldIdEERKS2_h [0x10a5e62+0x602]
module: C:\PROGRA~1\BLUECF~1\OpenFOAM-5.x\platforms\mingw_w64GccDPInt32Opt\lib\libOpenFO AM.dll
ZN4Foam8fvMatrixIdE15solveSegregatedERKNS_10dictio naryE [0x65ef1c17+0x127]
module: C:\PROGRA~1\BLUECF~1\OpenFOAM-5.x\platforms\mingw_w64GccDPInt32Opt\lib\libfinite Volume.dll
(No symbol) [0x44f711]
module: C:\PROGRA~1\BLUECF~1\OpenFOAM-5.x\platforms\mingw_w64GccDPInt32Opt\bin\chtMultiR egionSimpleFoam.exe
(No symbol) [0x44f9b5]
module: C:\PROGRA~1\BLUECF~1\OpenFOAM-5.x\platforms\mingw_w64GccDPInt32Opt\bin\chtMultiR egionSimpleFoam.exe
(No symbol) [0x486a91]
module: C:\PROGRA~1\BLUECF~1\OpenFOAM-5.x\platforms\mingw_w64GccDPInt32Opt\bin\chtMultiR egionSimpleFoam.exe
(No symbol) [0x4013f7]
module: C:\PROGRA~1\BLUECF~1\OpenFOAM-5.x\platforms\mingw_w64GccDPInt32Opt\bin\chtMultiR egionSimpleFoam.exe
(No symbol) [0x40152b]
module: C:\PROGRA~1\BLUECF~1\OpenFOAM-5.x\platforms\mingw_w64GccDPInt32Opt\bin\chtMultiR egionSimpleFoam.exe
BaseThreadInitThunk [0x7ff8ca493dc4+0x14]
module: C:\WINDOWS\System32\KERNEL32.DLL
RtlUserThreadStart [0x7ff8cc7b3691+0x21]
module: C:\WINDOWS\SYSTEM32\ntdll.dll


Someone has any idea of what is wrong ?




Best regards

[julieng]

Ok, I found that it is not good to create groups for inside boundaries between domains. The command "splitMeshRegions -cellZones -overwrite" creates itself these boundaries.
So I have results close to these obtained with blockMesh but I have a strange fluctuation close to the outlet of the top air domain giving waves in monitoring error curves and in field T


Heat flux is fluctated also at the fluid/ solid interface giving close to 130 W

at the boundary. 131 W for the bockMesh case.


I don't know if someone find difference between CAD mesh and blockMesh for 2 identical mesh.

[julieng]

The converge curve for the top fluid domain is pretty bad

[julieng]

I post the differences between meshes obtained with Salome and blockMesh:


Salome Mesh :


Mesh stats
points: 50802
internal points: 0
faces: 100550
internal faces: 49700
cells: 25050
faces per cell: 5.99800399
boundary patches: 11
point zones: 0
face zones: 0
cell zones: 3

Overall number of cells of each type:
hexahedra: 25000
prisms: 50
wedges: 0
pyramids: 0
tet wedges: 0
tetrahedra: 0
polyhedra: 0

Checking topology...
Boundary definition OK.
Cell to face addressing 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
minXplate 50 102 ok (non-closed singly connected)
maxXplate 100 202 ok (non-closed singly connected)
top_bottom_plate 10100 10402 ok (non-closed singly connected)
inlet_botAir 100 202 ok (non-closed singly connected)
minZ_botAir 100 202 ok (non-closed singly connected)
outlet_botAir 100 202 ok (non-closed singly connected)
top_bottom_botAir 20000 20402 ok (non-closed singly connected)
inlet_topAir 100 202 ok (non-closed singly connected)
maxZ_topAir 100 202 ok (non-closed singly connected)
outlet_topAir 100 202 ok (non-closed singly connected)
top_bottom_topAir 20000 20402 ok (non-closed singly connected)

Checking geometry...
Overall domain bounding box (0 0 0) (0.5 1 0.5)
Mesh has 2 geometric (non-empty/wedge) directions (1 0 1)
Mesh has 2 solution (non-empty) directions (1 0 1)
All edges aligned with or perpendicular to non-empty directions.
Boundary openness (0 -4.86129149e-017 0) OK.
Max cell openness = 1.26904551e-016 OK.
Max aspect ratio = 12.5 OK.
Minimum face area = 1e-006. Maximum face area = 0.00586026339. Face area magnitudes OK.
Min volume = 1e-006. Max volume = 2.9301317e-005. Total volume = 0.25. Cell volumes OK.
Mesh non-orthogonality Max: 68.1985905 average: 2.87277745
Non-orthogonality check OK.
Face pyramids OK.
Max skewness = 0.229088402 OK.
Coupled point location match (average 0) OK.

Mesh OK.

End



Mesh obtained with blockMesh:


Mesh stats
points: 50702
internal points: 0
faces: 100350
internal faces: 49650
cells: 25000
faces per cell: 6
boundary patches: 5
point zones: 0
face zones: 0
cell zones: 3

Overall number of cells of each type:
hexahedra: 25000
prisms: 0
wedges: 0
pyramids: 0
tet wedges: 0
tetrahedra: 0
polyhedra: 0

Checking topology...
Boundary definition OK.
Cell to face addressing 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
maxY 100 202 ok (non-closed singly connected)
minX 250 502 ok (non-closed singly connected)
maxX 250 502 ok (non-closed singly connected)
minY 100 202 ok (non-closed singly connected)
defaultFaces 50000 50702 ok (non-closed singly connected)

Checking geometry...
Overall domain bounding box (0 -0.25 0) (0.5 0.25 1)
Mesh has 2 geometric (non-empty/wedge) directions (1 1 0)
Mesh has 2 solution (non-empty) directions (1 1 0)
All edges aligned with or perpendicular to non-empty directions.
Boundary openness (2.77555756e-017 -4.4408921e-017 -1.16624917e-015) OK.
Max cell openness = 1.87459585e-016 OK.
Max aspect ratio = 55.2387824 OK.
Minimum face area = 3.64820042e-007. Maximum face area = 0.0100379816. Face area magnitudes OK.
Min volume = 3.64820042e-007. Max volume = 9.12050095e-005. Total volume = 0.25. Cell volumes OK.
Mesh non-orthogonality Max: 0 average: 0
Non-orthogonality check OK.
Face pyramids OK.
Max skewness = 4.09891609e-014 OK.
Coupled point location match (average 0) OK.

Mesh OK.

End



I see that I have Mesh non orthogonality with Salome, do I have to modify something in the solver due to non orthogonalities ?


Any advises would be welcome


Best regards