[Julian121]

I have generated a hexa mesh for a rotor which has a tip clearance in ICEM. When I use this mesh, I get the following error. The location that CFX reports is close to the trailing edge and it seems that when I lower the distance to the first node this happens.
I have checked the mesh in this area and it seems that the edge associations are correct but the edge to first node is slightly off the shroud surface.
Can someone please advise me on how to fix this problem?

| ERROR #002100080 has occurred in subroutine CHECK_NORMV. |
| Message: |
| The specified velocity vector on the boundary patch |
| Rotor Shroud |
| has a significant normal component at one or more faces. One of |
| these face locations is |
| (x,y,z) = ( 2.01872E-01,-2.31752E-02, 6.00350E-02). |
| The angle between the specified velocity and the element surface is|
| 37.085 degrees at this face. This is considered an error because |
| it implies that the mesh is moving. The following are possible |
| reasons for the error message: |
| 1. There is a setup error; for example, an incorrect axis of |
| rotation. |
| 2. There may be a meshing problem; for example, the nodes on a |
| rotating surface might not lie on the surface of revolution. |
| 3. The boundary is curved and the mesh is very coarse. In this |
| case, you may modify the tolerance by increasing the |
| expert parameter 'tangential vector tolerance wall' |
| from its default of 20 degrees.

[Gert-Jan]

I see a mesh that is not aligned. And it looks like these elements are on a symmetry plane, not? Then, CFX complains about the elements that are not in plane. There is a blunt method: instead of using a symmetry plane, use a free slip wall.
Alternatively, you should go back to ICEM and carefully look at the associations of the blocking (vertices, edges & faces) to the geometry (points, cuves & surfaces). Probably this is not consistent.

[Julian121]

Originally Posted by Gert-Jan

I see a mesh that is not aligned. And it looks like these elements are on a symmetry plane, not? Then, CFX complains about the elements that are not in plane. There is a blunt method: instead of using a symmetry plane, use a free slip wall.
Alternatively, you should go back to ICEM and carefully look at the associations of the blocking (vertices, edges & faces) to the geometry (points, cuves & surfaces). Probably this is not consistent.

No symmetry plane was used. Periodicity was defined by default in ICEM under global mesh setup.
There is no problem in hub even if I refine mesh near the blade.
The area that has problem disappears when I use less nodes near the blade in shroud.
I even removed the blocks inside the tip clearance and rescaled the ogrid but still the the mesh in the boundary layer is not aligned correctly.
I have tried many times but it does not change at all.
May I send it to you?

[Gert-Jan]

Yeah sure. It's holiday time anyway. No guarantee though.