FLUENT adding mesh nodes problem when importing 3D mesh from ICEM
 

I have generated 3D mesh with ICEM, and it looks great, shown in first picture.

Then I converted mesh to unstructured mesh and output mesh (as FLUENT V6) in ICEM.

However, when I input the mesh files in FLUENT, I check the mesh, the mesh shells are good (second picture) but the mesh inside fluid (I make a middle cut) looks strange, something is added to the mesh.

I checked the mesh info from ICEM and FLUENT, they are same.

AND this problem only occur for some 3D meshes, not for 2D meshes. I doesn't know if FLUENT really modify the mesh.

ICEM:
-- Mesh Info ---
Element types :
LINE_2 : 1232
HEXA_8 : 491520
QUAD_4 : 39680
Element parts :
BOTTOM : 7168
CRVS : 832
FLUID : 491520
INLET : 2048
OUTLET : 2048
SYM : 7680
TOP : 7168
WALL : 3584
WING : 8208
WINGTIP : 2176
Total elements : 532432
Total nodes : 511545


FLUENT :
491520 hexahedral cells, zone 11, binary.
491520 cell partition ids, zone 11, 32 partitions, binary.
1454720 quadrilateral interior faces, zone 12, binary.
7168 quadrilateral symmetry faces, zone 20027, binary.
3584 quadrilateral symmetry faces, zone 17, binary.
7808 quadrilateral wall faces, zone 40060, binary.
2176 quadrilateral wall faces, zone 40061, binary.
2048 quadrilateral velocity-inlet faces, zone 14, binary.
2048 quadrilateral pressure-outlet faces, zone 15, binary.
7680 quadrilateral symmetry faces, zone 16, binary.
7168 quadrilateral symmetry faces, zone 20026, binary.
511545 nodes, binary.
511545 node flags, binary.

Well there is no need to worry.

Because mesh are not 100% aligned in coordinates axis. So when you see the cut plane it show you the different elements with sort of projection on your specified plane.

So this is just a visualization or understanding problem.

bravo for getting good quality and good looking mesh in ICEM CFD.

Thank you very much!!

Yes, it takes me lots of time to have good mesh. however, it still haven't reach mesh independent and need more improvement.