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#1 |
New Member
george
Join Date: Feb 2021
Posts: 16
Rep Power: 5 ![]() |
Hello,
I have a simple multi region heat transfer case such as attached scheme.png file. To define the inlet and outlet patches of the flow channel, I am exporting the mesh as three separate patches: inlet.stl, outlet.stl, and wall.stl. Then, using this command: Code:
cat inlet.stl outlet.stl wall.stl > MERGE.stl Code:
geometry { MERGE.stl { type triSurfaceMesh; name fluidRegion; regions { inlet {name inlet;} outlet {name outlet;} wall {name wall;} } } }; refinementSurfaces { fluidRegion { level (1 1); regions { inlet { level (1 1); patchInfo { type patch;}} outlet { level (1 1); patchInfo { type patch;}} wall { level (3 3); patchInfo { type wall;}} } } } Code:
//constant/polyMesh ( solidboundaries { type wall; } inlet { type patch; //why these 3 are here? } outlet { type patch; } wall { type wall; } } Code:
//solidregion BCs (0/solidregion/T) boundaryField { wall ?????? { type fixedValue; value V; } solidregion_to_fluidregion { type compressible::turbulentTemperatureRadCoupledMixed; value uniform V; Tnbr T; kappaMethod solidThermo; } } Code:
//fluidregion BCs (0/fluidregion/T) boundaryField { wall ?????? { type zeroGradient; } inlet { bc } outlet { bc } solidregion_to_fluidregion { type compressible::turbulentTemperatureRadCoupledMixed; value uniform V; Tnbr T; kappaMethod solidThermo; } } Best regards, scfd |
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#2 |
Senior Member
Yann
Join Date: Apr 2012
Location: France
Posts: 1,169
Rep Power: 27 ![]() |
Hello scfd,
You post lack some information, but lets try to clarify: When meshing a multiregion, we usually follow these steps (let me know if you do things differently):
blockMesh and snappy will write meshes in constant/polyMesh. So after running snappy you get a single mesh containing all your regions in constant/polyMesh. This is why you see all the patches for all regions here. Then you run splitMeshRegions, which will read constant/polyMesh, split the mesh, create the interfaces between regions (mappedWall) and create new directories containing separate mesh for each region. In your case, it will write constant/solidRegion/polyMesh to store the solid mesh and constant/fluidRegion/polymesh for the fluid mesh. constant/polyMesh is useless for your simulation. chtMultiRegionFoam will not use it, it will only look for region meshes in constant/solidRegion and constant/fluidRegion. For the boundary conditions, you need to defined it in 0/solidRegion and 0/fluidRegion, according to the boundary files located in constant/solidRegion/polyMesh and constant/fluidRegion/polyMesh, respectively. I hope this helps, Yann |
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#3 |
New Member
george
Join Date: Feb 2021
Posts: 16
Rep Power: 5 ![]() |
Hi Yann,
Thank you for your quick response. I couldn't explain myself well. The issue here is that even though the STL patches (inlet, outlet, and wall - I'll call it wall_of_fluid to avoid confusion) belong to the fluid region, the wall_of_fluid patch exists in solidregion/polyMesh/boundary. Similarly, why does the boundary condition assigned with ".*" automatically create a bc for wall_of_fluid in both the fluid region and solid region bc dicts? Shouldn't it be only mappedWall? Code:
0.orig/fluidregion/T: "." { type zeroGradient; } inlet { type fixedValue; } outlet { type inletOutlet; } "fluidregion_to_." { type compressible::turbulentTemperatureRadCoupledMixed; } Code:
0.orig/solidregion/T: "." { type fixedValue; } "solidregion_to_." { type compressible::turbulentTemperatureRadCoupledMixed; } On the same surface (even though it has two different names as fluidregion_to_solidregion and wall_of_fluid, the surface is the same), there are zeroGradient, fixedValue, and compressible::turbulentTemperatureRadCoupledMixed boundary conditions. Isn't there something wrong here? regards scfd |
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#4 | |
Senior Member
Yann
Join Date: Apr 2012
Location: France
Posts: 1,169
Rep Power: 27 ![]() |
Alright, have you checked in ParaView to see what is going on and what is this "wall_of_fluid" in your solid region?
Do you get some faces assigned as wall_of fluid and others as fluidRegion_to_solidRegion? Quote:
Since you have a wall patch which shouldn't exist anymore in your constant/fluidRegion/polyMesh/boundary, it gets the boundary condition defined in the wildcard. The source of the problem is the mesh not being properly defined, so this is the part you need to fix. What's the output of splitMeshRegions? Regards, Yann |
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#5 |
New Member
george
Join Date: Feb 2021
Posts: 16
Rep Power: 5 ![]() |
In the output of splitMeshRegions, everything is as it should be. I have never encountered something like this before. I feel like if I change my method of creating the inlet and outlet, I might get rid of this issue. I think I need to create only the inlet and outlet without defining wall_of_fluid. For this, I will define inlet.stl and outlet.stl separately in the geometry section and also define fluid.stl as a single piece to create the region. For now, I will continue to investigate. I will update this place once I solve the problem.
Code:
Number of regions:2 Region Cells ------ ----- 0 15840 1 70560 Region Zone Name ------ ---- ---- 0 (0) fluidregion 1 (1) solidregion Sizes of interfaces between regions: Interface Region Region Faces --------- ------ ------ ----- 0 0 1 11520 Reading volScalarField: cellToRegion Adding patches Adding patches For interface between region fluidregion and solidregionadded patches 5 fluidregion_to_solidregion 6 solidregion_to_fluidregion Region 0 -------- Creating mesh for region 0 fluidregion Mapping fields Mapping field cellToRegion Deleting empty patches Writing new mesh Writing addressing to base mesh Writing map pointRegionAddressing from region0 points back to base mesh. Writing map faceRegionAddressing from region0 faces back to base mesh. Writing map cellRegionAddressing from region0 cells back to base mesh. Writing map boundaryRegionAddressing from region0 boundary back to base mesh. Region 1 -------- Creating mesh for region 1 solidregion Mapping fields Mapping field cellToRegion Deleting empty patches Writing new mesh Writing addressing to base mesh Writing map pointRegionAddressing from region1 points back to base mesh. Writing map faceRegionAddressing from region1 faces back to base mesh. Writing map cellRegionAddressing from region1 cells back to base mesh. Writing map boundaryRegionAddressing from region1 boundary back to base mesh. End scfd |
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Tags |
multiregion, pacth |
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