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[ICEM] Quarter O-Grids and Quality Issues

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Old   May 14, 2020, 15:35
Default Quarter O-Grids and Quality Issues
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Dear ICEM Community,

I have a geometry comprising of a conical body in ICEM CFD. The geometry itself is pretty complex comprising of propeller blades mounted on a streamline body comprised of two cones. The overall quality metric (minimum) of the Pre-Mesh is 0.2 (I'm trying to improve this further a bit). The Determinant (3x3x3) of the Pre-Mesh however is giving me negative values only in one of the 6 Quarter O-Grids I have made around the conical tips in the front and back cones. Can somebody comment on why this is such and what I may do to fix this?
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Old   May 15, 2020, 13:38
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Hi aunmhd,


it seems a few blocks might became inverted, because there isn't any element with a determinant close to zero.



there is a feature called "fix inverted blocks" you may try it a few times and see whether it fixed it.
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Old   May 15, 2020, 16:50
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Thanks bluebase,

The problem seemed to be originating from inverting blocks as you correctly pointed out. I was able to fix this issue by the 'Invert Selected Blocks' feature only selecting the blocks of the O-Grid. Using 'Fix Inverted Blocks' fixes the problem in the O-Grid but also inverts other blocks elsewhere in the domain which were otherwise properly 'aligned'. This continues in an endless loop where blocks are inverted rather randomly in the domain.

While we are on this could you please elaborate what is the significance of this quality metric determinant 3x3x3 and what minimum value is acceptable for solvers in general.

Thanks.
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Old   May 16, 2020, 04:51
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Determinant 3x3x3
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