Warning about Symmetry boundary face
pkck28 opened this issue · 1 comments
I am running adflow and at the start of the analysis I get a warning:
Symmetry boundary face BC9 of zone domain.00003 is not planar.
Maximum deviation from the mean normal: 7.75206E+00 degrees
I know this is coming from the mesh, but I wanted to know more about this warning and how can I get rid of them. I have following questions about the warning:
- Is mean normal the mean of all the normal of the faces in that particular of zone of the mesh?
- Can I ignore this ignore and not comprise the analysis result?
- How much maximum deviation can be ignored, if ignoring is okay in the first place?
Any help would be appreciated!
The mean normal is the mean of the face normals in that CGNS block projected in the direction of the symmetry plane normal. As a result, the mean normal points in the same direction as the normal to the symmetry plane.
The effect of non-planar faces on the accuracy of the analysis depends on the size of the block as well as the angle. For example, I have seen a 2 deg deviation on a small block result in almost no change in the output lift and drag. An 8 deg deviation is most likely too large to ignore.
In addition, if you are planning on running shape optimizations with MACH-Aero, any amount of deviation can be problematic. Even small deviations can cause major issues with the volume mesh warping (IDWarp).