3d blade mesh problems
 

Hi all

I am trying to create a 3d grid of a blade with flat tips. I have been making 2d grids so I am not new with the blocking strategy but in 3d things get rather complicated. I end up with low quality mesh.I am sure that I am doing something in my blocking stategy.

I have links of the steps I make my meshing procedure so it's easier to point out what is wrong.

Thanks in advance.

1.The farfield and theblade(http://147.102.42.169/3dgrid/1.png)
2.Created the 3D Bounding box associated the edges and made an O-grid split
using the faces at the outflow and those "pointing" in the flat tips of the blade.(http://147.102.42.169/3dgrid/2.png)
3.I split in the "X" and "Z" direction to embrace the blade with a block
(http://147.102.42.169/3dgrid/3.png)
(http://147.102.42.169/3dgrid/4.png)

4. I delete the block embracing the blade an make edge association to match the blade boundaries
(http://147.102.42.169/3dgrid/5.png)

5.The problems start here,because i have to collapse the "trailing edge" blocks.
(http://147.102.42.169/3dgrid/6.png)
(http://147.102.42.169/3dgrid/7.png)
(http://147.102.42.169/3dgrid/8.png)
6.The resulting block structure has this strange triangle-shaped block which produces very strange elements.(in the picture I have removed a layer of blocks)
(http://147.102.42.169/3dgrid/9.png)

I am sure that my blocking strategy is the problem.I would appreciate any ideas or thoughts.

Thanks again

Hello papis,

Do not delete the block embracing the blade. Create c grid around the blade and extend it in both Z direction till the boundary. Then you collapse the tte wake blocks as you did and also the block inside the blade.

regards
Jeevan

Hi Jeevan,

Thanks for your reply.I am not sure I understand what you say. Whether or not I delete the block embracing the airfoil doesn't make any practical difference.After I collapse the trailing edge block these "wedge" shaped boxes appear(from the flat tip to the farfield,I can't collapse those because i will lose the flat tip boundary).

Take a look at the resulting blocks after collapsing the blocks of the trailing edge.

http://147.102.42.169/3dgrid/wedgeb.png

Thanks again for your time

i am sorry it was my mistake in understanding the issue.
You can do one thing you can create Y-grid for the degenerated wedge shape blocks, this might improve the quality.

Yeah,you are right Y-grid conversion makes the quality better.

Thanks a lot