[ANSYS Meshing] Jump in Cell Size when Growth Rate > 1.1 (2D structured Mesh)

bmseo8pvk · January 9, 2023, 12:51

Hello everyone,

I want to simulate a 2D airfoil using a structured C-mesh similar to this one: https://www.cfd-online.com/W/images/...mesh_final.JPG. Therefore I made a couple of sizings with a fixed number of divisions and a Multizone Quad/Tri Method. Overall the mesh looks correct, but in the area close to the airfoil the growth rate of the cells is strange as shown in this image:

https://imgur.com/a/1qwEq9r

I found out that it has to do with the growth rate of the sizing orthogonal to the surface (actually boundary, since it's 2D) of the airfoil. If I set it to 1.1 it looks fine:

https://imgur.com/a/kBvNjKI

The threshold seems to be around 1.11.
What am I doing wrong?

Gert-Jan · January 11, 2023, 12:01

Don't use links to external websites for showing images. I won't open them.

Open this page on cfd-online to learn how to post images
https://www.cfd-online.com/Wiki/Ansy...n_the_forum.3F

bmseo8pvk · January 12, 2023, 12:35

Let me give you some more info. I guess my initial post was a bit too brief.

These are the sizings with bias:
12-01-2023-1673533724-mceclip0.jpg
red:
12-01-2023-1673533836-mceclip1.png
blue:
12-01-2023-1673533894-mceclip2.png
All edges have sizings. The ones without Bias have a fixed number of divisions similar to this:
12-01-2023-1673534145-mceclip3.png
The Multizone Method looks like this:
12-01-2023-1673534191-mceclip4.png

January 9, 2023, 12:51	Jump in Cell Size when Growth Rate > 1.1 (2D structured Mesh)	#1
bmseo8pvk New Member Join Date: Jan 2022 Posts: 3 Rep Power: 4	Hello everyone, I want to simulate a 2D airfoil using a structured C-mesh similar to this one: https://www.cfd-online.com/W/images/...mesh_final.JPG. Therefore I made a couple of sizings with a fixed number of divisions and a Multizone Quad/Tri Method. Overall the mesh looks correct, but in the area close to the airfoil the growth rate of the cells is strange as shown in this image: https://imgur.com/a/1qwEq9r I found out that it has to do with the growth rate of the sizing orthogonal to the surface (actually boundary, since it's 2D) of the airfoil. If I set it to 1.1 it looks fine: https://imgur.com/a/kBvNjKI The threshold seems to be around 1.11. What am I doing wrong?

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January 11, 2023, 12:01		#2
Gert-Jan Senior Member Gert-Jan Join Date: Oct 2012 Location: Europe Posts: 1,910 Rep Power: 28	Don't use links to external websites for showing images. I won't open them. Open this page on cfd-online to learn how to post images https://www.cfd-online.com/Wiki/Ansy...n_the_forum.3F

January 12, 2023, 12:35		#3
bmseo8pvk New Member Join Date: Jan 2022 Posts: 3 Rep Power: 4	Let me give you some more info. I guess my initial post was a bit too brief. These are the sizings with bias: 12-01-2023-1673533724-mceclip0.jpg red: 12-01-2023-1673533836-mceclip1.png blue: 12-01-2023-1673533894-mceclip2.png All edges have sizings. The ones without Bias have a fixed number of divisions similar to this: 12-01-2023-1673534145-mceclip3.png The Multizone Method looks like this: 12-01-2023-1673534191-mceclip4.png