[ddyy]

Hello everyone, weird 2D boundary mesh appear when i generate mesh about blade profile. could you please tell me what may cause this results and how to solve it. Thank you very much!

[ddyy]

Really need your help!

[-mAx-]

Try to split your geometry

[ddyy]

Originally Posted by -mAx-

Try to split your geometry

Thanks for your reply.Could you please give more specific description about "split geometry"?

[-mAx-]

https://www.sharcnet.ca/Software/Gam...guide/tg04.htm

[ddyy]

I have read the tutorial carefully and learned a lot. But here is 2D model. So,the approach which shows in the tutorial still works? Or anyother suggestion could you give me? Thank you -mAx-.

[-mAx-]

Sure it works.
You only have to split surface with edge for 2d instead of volume with surface.
I don't know where the problem is in your foil, but usually it degenerates on long edges.
So in your case I would try to split the red and green edges.
Capture.JPG
If you are still stucked with it, you can provide me your dbs file

[ddyy]

Oh, it is really nice of you ,here is my dbs file.

[-mAx-]

Alright,
First I saw that you splitted the edges with your desired element size.
It is not necessary to do that, indeed you can control the size or amount of element along one edge within the edge mesh tools.
So in your case I merged all the edges as it should be, and I tried.
I didn't get your issue

Capture1.jpg

Capture2 (2).jpg

Capture.jpg

Check this tutorial
https://www.sharcnet.ca/Software/Gam...guide/tg08.htm

[ddyy]

yes,sir.I found that this deformed boundary grid appear when the first boudary layer height is too low(1e-5 m). As you can see, the quality of boundary mesh is good when i increase the first row height(1e-4 m). So,there is another question, how can i keep the quality of boundary mesh when i need to ensure low first layer height for turbulence model?

[-mAx-]

what is you minimal first cell height?
I can go up to 5e-6

Then will be aspect ratio from cell to high.
That means you have to increase the number of points on your edges

[ddyy]

I can go just 3e-5.That is really confused. Can i get your .dbs file? I want to know the difference between us. In the end, thank you very very much. Have a nice day!

[-mAx-]

you have to remesh the domain
1.zip

[ddyy]

Dear Mr.Maxime Perelli
I see the difference. The version of gambit which i used is 2.2.30. And you use version 2.4.x. The mesh quality is great when i turn to version 2.4.6 even if i set first layer height to 1e-5.. Thank you for your help.
yours sincerely
dy