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atareen64 June 16, 2011 11:10

blockMesh - help
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Dear All,

I created a half laval-nozzle mesh using blockMesh and I put some effort into it. When I ran blockMesh, the mesh got created but with a lot of warnings like 'zero or negative pyramid volume'. And even though I am able to view the mesh in paraview, the I can't run the solver on it because it fails three mesh checks.

I have a hunch as to what could be wrong with the mesh but I'm not sure. Can anybody look at the mesh or the blockMesh warnings and tell me what's going on?

I'm uploading the mesh and a test case so anybody can generate blockMesh without trouble.

Thanks a lot!


MartinB June 16, 2011 12:13

Hi Ammar,

change the z-coordinates of your vertices from ( x y 5.0 ) to ( x y -5.0 ). Be careful with your vertices 76, 77, 78, 79 when using a replace command in a text editor.

As an alternative you can renumber all the hex blocks: take the last four digits and place them before the first four digits.

Have fun


atareen64 June 16, 2011 15:32


Thank you for that suggestion, it worked. Silly mistake, Thanks a lot!


er10 June 14, 2017 11:21


Originally Posted by atareen64 (Post 312326)

Thank you for that suggestion, it worked. Silly mistake, Thanks a lot!



Could you share your final blockMeshDict file with the half nozzle that you used? How did you write this file? Any chance you know how to output a blockMeshDict file from a nozzle CAD file? I'm looking to do a 2D axisymmetric study.


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