[Other] Some cellSets generated while some cellSet now size 0

Eubo · February 15, 2023, 13:36

Hi,

Case: I am running a case of buoyantBoussinesqPimpleFoam. It comprises of cuboids in a grid (as shown in the image) Each cuboid has a volumetric heat source on one of it's face, being defined in topoSetDict. I am creating the mesh using blockMesh and later snappyHexMesh

Problem: After running topoSet, all cellSets are created. BUT only partial cellSets have a finite sizes while others have size 0. Through checkMesh The volume bounding box of these cellSets are (1e+150 1e+150 1e+150) (-1e+150 -1e+150 -1e+150).

Mehodology:
>blockMesh >topoSet >surfaceFeatureExtract >snappyHexMesh >checkMesh >buoyantBoussinesqPimpleFoam

Apart from the fact that some cellSets have no size and therefore no heat release, everything else in the simulation was running smoothly. checkMesh was ok and the case hasn't diverged as yet.

Previous debugging attempts: Based on other threads in the forum, I have tried to:
- check the units across dictionaries. Everything is in meters
- added the term 'sourceInfo'. It was working without it too and did not change anything on adding
- verified domain size. The cellSets are within the domain bounds

Questions:
1. Why do some cellSets have size 0. Is it a problem in my topoSetDict?
2. Is it possible to see the sets when I open the mesh in Paraview? how?

topoSet.txt

checkmesh.txt

topoSetDict.txt

Eubo · February 19, 2023, 23:41

I was able to solve the issue. I'll describe it here, in case someone faces the same problem in future

Reason behind the issue: blockMesh was creating coarse grid (that was supposed to be later refined by snappyHexMesh), due to which some of my cellZones became smaller than the grid mesh and were not generated at all. Eg. Blockmesh grid was 6*6m, while cellZone depth was 2m.

Solution: Commands run in the following order blockMesh>surfaceFeatureExtract>snappyHexMesh>topo Set. Now, the grid created by snappyhexMesh is much smaller and cellZones of 2m are able to generate.

Hope this helps!

February 15, 2023, 13:36	Some cellSets generated while some cellSet now size 0	#1
Eubo New Member Join Date: Sep 2022 Posts: 5 Rep Power: 3	Hi, Case: I am running a case of buoyantBoussinesqPimpleFoam. It comprises of cuboids in a grid (as shown in the image) Each cuboid has a volumetric heat source on one of it's face, being defined in topoSetDict. I am creating the mesh using blockMesh and later snappyHexMesh Problem: After running topoSet, all cellSets are created. BUT only partial cellSets have a finite sizes while others have size 0. Through checkMesh The volume bounding box of these cellSets are (1e+150 1e+150 1e+150) (-1e+150 -1e+150 -1e+150). Mehodology: >blockMesh >topoSet >surfaceFeatureExtract >snappyHexMesh >checkMesh >buoyantBoussinesqPimpleFoam Apart from the fact that some cellSets have no size and therefore no heat release, everything else in the simulation was running smoothly. checkMesh was ok and the case hasn't diverged as yet. Previous debugging attempts: Based on other threads in the forum, I have tried to: - check the units across dictionaries. Everything is in meters - added the term 'sourceInfo'. It was working without it too and did not change anything on adding - verified domain size. The cellSets are within the domain bounds Questions: 1. Why do some cellSets have size 0. Is it a problem in my topoSetDict? 2. Is it possible to see the sets when I open the mesh in Paraview? how? topoSet.txt checkmesh.txt topoSetDict.txt

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February 19, 2023, 23:41		#2
Eubo New Member Join Date: Sep 2022 Posts: 5 Rep Power: 3	I was able to solve the issue. I'll describe it here, in case someone faces the same problem in future Reason behind the issue: blockMesh was creating coarse grid (that was supposed to be later refined by snappyHexMesh), due to which some of my cellZones became smaller than the grid mesh and were not generated at all. Eg. Blockmesh grid was 66m, while cellZone depth was 2m. Solution:* Commands run in the following order blockMesh>surfaceFeatureExtract>snappyHexMesh>topo Set. Now, the grid created by snappyhexMesh is much smaller and cellZones of 2m are able to generate. Hope this helps!