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[snappyHexMesh] Jagged edges after snappyhexmesh around cylinder

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Old   June 18, 2015, 09:44
Unhappy Jagged edges after snappyhexmesh around cylinder
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Vaibhav
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Hi

I am simulating the flow and calculating heat transfer values for a traditional Indian chuhla(gas stove). In my problem hot air goes through the stove pipe(dia 8 cm) and impinges on a pan(dia 31 cm). Pan is a cylindrical object kept at constant temperature, distance between nozzle exit and pan wall is 2 cm and I have assumed outlet to be 100 cm far from the centreline for it to be sufficiently far that the zero gradient conditions can be applied.

My boundary are:

1) inlet
2) pipewall
3) panwall
4) vesselwall (it's the stove wall)
5) outlet

I have meshed in Salome and exported stl files.

The problem is that, after meshing by snappyhexmesh, if I see a slice view at the bottom wall of the pan I get a circular negative with jagged edges inside, ideally it should be a perfect circular negative.

I have attached the image of the entire domain and the problem near the pan wall.

Any help would be appreciated. I have tried snapEdge, refining the mesh
near the pan etc.

Link to the case: https://www.dropbox.com/s/gjnj5zjpgu...al.tar.gz?dl=0

Vaibhav
Attached Images
File Type: jpg unwanted_edges.jpg (96.5 KB, 37 views)
File Type: jpg domain.jpg (22.5 KB, 24 views)
File Type: jpg unwanted.jpg (17.3 KB, 40 views)

Last edited by vaibhav.antil; June 18, 2015 at 14:32. Reason: Redefining the case in detail
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Old   June 18, 2015, 13:51
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Saideep
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Hi Vaibhav;

I was not able to open your link. Gives me some error link.

Well, first question.

Which software did you use to create your .stl object shape? My initial guess is that the problem lies over there itself.

The best way to check is that just view your .stl image in paraview. Do you see these cuts even there? (I guess yes).

Once that is fine it is simple and straight forward.

Saideep
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Old   June 18, 2015, 14:36
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Vaibhav
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Quote:
Originally Posted by Saideep View Post
Hi Vaibhav;

I was not able to open your link. Gives me some error link.

Well, first question.

Which software did you use to create your .stl object shape? My initial guess is that the problem lies over there itself.

The best way to check is that just view your .stl image in paraview. Do you see these cuts even there? (I guess yes).

Once that is fine it is simple and straight forward.

Saideep
Hi Saideep

Thanks a lot for your prompt response and I apologise that I wasn't clear earlier. I have updated my post to clearly define the problem.

I have used Salome to make the stl files. As mentioned I expect this to be a perfect circular negative not with these edges. The boundary associated with it is panwall.

I have clipped my domain at a distance of 0.10, which basically shows the entire pan and a magnified view of the bottom wall of the pan. I have attached one more clip view at 0.11 which is basically at the bottom wall and shows clearly no such jagged edges or cuts. Something is happening after snappyhexmesh only.

Vaibhav
Attached Images
File Type: jpg paraview_pan.jpg (94.4 KB, 25 views)
File Type: jpg magniified view.jpg (97.7 KB, 29 views)
File Type: jpg clipview.jpg (96.6 KB, 30 views)

Last edited by vaibhav.antil; June 19, 2015 at 01:14. Reason: Adding images of .stl files in paraview
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