[daniel.struwig]

I'm new to NUMECA and was wondering if someone could give me a general guideline as to what values should be attained or not to be exceeded regarding the orthogonality, expansion and aspect ratio. I'm currently simulating a KKK K27 compressor, but it seems that the b2b mesh quality at the hub is rather poor because of the large hub fillet (1.85mm). If the best mesh quality that I can attain still does not satisfy the minimum requirements is there any other way I could improve the mesh quality even if it means altering the geometry slightly.

Any help will be greatly appreciated.

[oldshoes81]

Hi Daniel,

The quality of mesh is the most important issue that you have to consider, in fact, it leads you to a better accuracy. Before looking at the orthogonality, first you would need to make sure there will not be a single negative cell. Then the range of expansion ratio and aspect ratio should be followed accordingly and lastly you should look into the orthogonality.

If you have difficult to obtain a better quality of mesh that you expected, you should alter the geometry of hub and/or shroud by expanding in Z direction.

I hope this is useful.