[Anna Tian]

I generate the grids in ICEM (figure2) and import them in CFX (figure1). But some grids are shown as figure3 in CFX pre.

I once got this kind of problem. If there are unexpected ‘lines’ as in figure3 shown in CFX pre, these ‘lines’ will become wall boundary which is what I don’t want. Coarsening the grids may solve the problem, but I need fine grids.

Has anyone ever got this problem as well? Any good ways to solve it?

[singer1812]

Did you do a mesh check in ICEM? Did it reveal single edges or missing internal faces?

I assume you made this via blocking and then transfered the block premesh into an unstructured mesh. Do you have a split vertices (non-common verticy) between 2 adjacent blocks?

Also, this mesh looks kind of funky. I think you would be better served creating an Ogrid around your entire structure (wing?). The grid will be alot smoother and you can remove those sharp mesh angles.

[Anna Tian]

Originally Posted by singer1812

Did you do a mesh check in ICEM? Did it reveal single edges or missing internal faces?

I assume you made this via blocking and then transfered the block premesh into an unstructured mesh. Do you have a split vertices (non-common verticy) between 2 adjacent blocks?

Also, this mesh looks kind of funky. I think you would be better served creating an Ogrid around your entire structure (wing?). The grid will be alot smoother and you can remove those sharp mesh angles.

Yes. I did premesh check in ICEM, including angle, determinant and volume change(grids expansion ratio). Even in CFX pre, if I zoom in the problematic region, I will see the grids there look not bad as well.

Yes. Block premesh to unstructured mesh. Never split a vertice. I only split block by cutting at the edge.

The topology looks not that normal. Because that's an airplane tail. The grids topology is constrained by the special geometry of the wing.

[singer1812]

I would suggest, in ICEM, turn on all shell elements, does that wall show up? Another thing, in ICEM, turn the node numbers on. Zoom into region that the wall is showing in PRE. Make sure there are not 2 nodes at the point. You might have to sew up that part, as ICEM might have put shell elements on that seam and therefore will not show anything wrong under MESH CHECK.

[Anna Tian]

Originally Posted by singer1812

I would suggest, in ICEM, turn on all shell elements, does that wall show up? Another thing, in ICEM, turn the node numbers on. Zoom into region that the wall is showing in PRE. Make sure there are not 2 nodes at the point. You might have to sew up that part, as ICEM might have put shell elements on that seam and therefore will not show anything wrong under MESH CHECK.

I did what you suggested (figures attached). Would you indicate whether you see any hints from them?

If it is 'nodes' problem, then why the problematic cells become less if I coarsening the grids?

[singer1812]

You need to attach the pics. Nothing came through.

[Anna Tian]

Originally Posted by singer1812

You need to attach the pics. Nothing came through.

Ya. I have added them on. Sorry. Now you can find them where are they missing.

[singer1812]

That doesnt look right. Those look like element numbers.

You should be looking for something like the attached. The node numbers are on. The nodes at the bottom are ok, they are single numbered.

The top 2 sets, if you look closely, each has 2 numbers over laid (the one on the right is easier to see, it has a green number and a black one).

I need to merge those to get a continous mesh. You should look for something similar in ICEM.

[Anna Tian]

Originally Posted by singer1812

That doesnt look right. Those look like element numbers.

You should be looking for something like the attached. The node numbers are on. The nodes at the bottom are ok, they are single numbered.

The top 2 sets, if you look closely, each has 2 numbers over laid (the one on the right is easier to see, it has a green number and a black one).

I need to merge those to get a continous mesh. You should look for something similar in ICEM.

Here it is. I don't see anything wrong with it.

[singer1812]

Those are point numbers. You need to display the Node numbers.

Right Click Mesh and on the Menu list that pops up, you will see Node Numbers. Select that.

[Anna Tian]

Originally Posted by singer1812

Those are point numbers. You need to display the Node numbers.

Right Click Mesh and on the Menu list that pops up, you will see Node Numbers. Select that.

Here it is. The figure attached is shown by right click on vertices, not points and show its numbers.