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[ICEM] Negative elements along and above turbine blade

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Old   February 3, 2021, 06:07
Default Negative elements along and above turbine blade
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James
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Hi,
I am creating a 120(deg) sector mesh around a turbine blade to then be rotated twice to create the full turbine. I am using a structured hexahedral mesh and seem to have a problem with elements around the blade and above the tip, propergating through the full domain, being negative. I have tried different types of blocking or edge associations and I can't seem to get rid of these poor quality nodes? I was wondering if anyone knew of a solution to this.
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File Type: png view of poor nodes.PNG (166.4 KB, 7 views)
File Type: jpg negative elements.jpg (13.2 KB, 3 views)
File Type: png neg selections.PNG (13.5 KB, 3 views)
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Old   February 4, 2021, 14:48
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Sebastian Engel
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Hi James,


it's difficult to inspect this problem from that views.


However, here a few tips what to do next:
I suggest, that you move the outer layer of vertices (at the circumference) closer to the actual surface. If the vertices are that far from the surface, you might get some weird auto projection
Do you know about the feature Scan planes? It is in the context menu of blocks, or premesh.
That feature allows you to inspect single layers of blocks within the domain. It helps in identifying how blocks are (ill-)formed.
Identify the current shape of the problematic blocks and develop a way to make them square again.


If you have splitted edges only in certain blocks, these splits do extend into the neighbouring blocks although not visibly. These invisible splits are dealt with automatically. In case of a complex blocking such automatic treatment can be cause of problems. It might be the case that the bunching is stretching elements unfavorably


Best,
Sebastian
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