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SnappyHexMesh Internal Flow Example (Diesel Injector)

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Old   July 7, 2013, 05:25
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Bruno Santos
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Hi Danny,

Without an example STL file, there isn't much I can suggest
You can try using OpenFOAM's commands surfaceCheck and surfaceClean.
The other possibility is to use either Blender or Meshlab for repairing the STL file.

Best regards,
Bruno
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Old   July 8, 2013, 08:00
Default stl file example
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Danny Moore
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here is an example stl file

Danny
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File Type: zip contraction.3 - Copy.zip (9.3 KB, 16 views)
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Old   July 13, 2013, 15:50
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Hi Danny,

I renamed the file to "test.stl" (OpenFOAM dislikes spaces and special characters) and ran:
Code:
surfaceCheck test.stl
And it gave serious indications of a bad surface mesh on this geometry. Almost 70% of the triangles have a quality lesser or equal 0.05 and the one with smallest quality has "0.000133138"!
And there seems to be problems with connections between triangles, since this is indicated:
Code:
Surface is not closed since not all edges connected to two faces:
    connected to one face : 12
    connected to >2 faces : 0
Conflicting face labels:12
But given the low quality triangles, this is only natural to occur.

If I'm not mistaken, the best procedure is to export to Step or IGES format and then use Salome to convert the surface mesh to STL. This is because SolidWorks is doing a very lousy job on converting this to STL.

The other possibility is to export the geometry to STL in binary form, so that you do not loose numerical precision. I say this because, for example from your file:
Code:
vertex 3.125293e+000 3.067232e+000 8.410000e+000
7 digits is far from enough for such bad quality triangles

Best regards,
Bruno
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Old   July 15, 2013, 07:45
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Thank you Bruno for your help! that makes sense with the troubles I was having! I appreciate your help!

Danny
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