Improve hexa mesh quality and determinant
 

Hello,

I am currently working with the mesh of a flame stabiliser in a quarter of a combustion chamber. I am considering only hexahedral elements, and a annular feed at the outlet face of the contraction. I have been working with this geometry in the past producing sensible meshes, but this one has a simulated weld at the inlet of the contraction, so i just added more ogrids to the mesh, and the quality is very bad, and also the determinant. Could you please help me with some tips on how to improve my mesh?
I attach some photos, they show my current geometry and mesh, as you can see I have created some ogrids for the annular feed and the simulated welding.
Attachment 68051

Attachment 68052

Attachment 68053

Attachment 68054

Attachment 68055

Many thanks!

Hi José,


it seems you have merged some blocks/vertices. So you end up with degenerated blocks and negative cells.
See the min/max of the determinant. The minimum is actually negative, which tells there are cells with negative volume (respective to the convention).





If cell count is not a big issue here, i suggest the following.
Project the block topology in the middle section onto the domain's end faces. Do not merge any blocks, move all vertices which are in-line in the z direction to the the same respective x-y-coordinates. The edges approx. in z direction should end up parallel with the axis. Or with other words, looking onto the blocking in the x-y-plane should show an almost congruent blocking.


It might be not clear enough what i mean. If that's the case try to understand your blocking a bit better first:
Use the feature Scan Planes to figure out how the blocks are formed; where they end up. You can find this feature in the context menu of Premesh (in the project tree).

It allows to draw selected layers of the premesh, so you can visualize their texture.


Best regards,
Sebastian