CFD Online Discussion Forums

CFD Online Discussion Forums (
-   FLOW-3D (
-   -   Meshing - Nested mesh block (

Mic February 12, 2009 04:57

Meshing - Nested mesh block
Hello everybody!

I was wondering if it is poosible to create graded meshes using multiple nested mesh blocks. The manual indicates that it is possible to nest ONE block mesh in another. Is it also possible to nest a block mesh in an already nested block mesh? Or is it generally not recommendable to build up such an hierarchic mesh structure?

(I am trying to handle HPDC-thin-walled casting parts)

Any comment is appreciated!

Regards m*

MC February 12, 2009 11:52

Re: Meshing - Nested mesh block
Hello, You can create as many nested-mesh blocks as you like however just remember that it will take more computational time. Best practice is to have fixed points aligning the mesh blocks and that the aspect ratios are no greater than 2.

CK February 12, 2009 20:22

Re: Meshing - Nested mesh block
Hi i believe multiple nested-block will introduced fluids volume conv error and eventually impact accuracy. so, better reduced number of nested blocks. Believe this is another major improvement needed by flow-3d.

MC February 13, 2009 11:21

Re: Meshing - Nested mesh block
Interesting. Never had that problem before. What version and how many nested blocks did you have when you got the fluids volume conv error and what percent of fluid volume conv error did you see?

CK February 14, 2009 04:12

Re: Meshing - Nested mesh block
i'm using v9.3.1 and max conv error is ~ 20% with 2 nested mesh blocks.

Michael February 14, 2009 21:53

Re: Meshing - Nested mesh block
I wouldn't think nulti-nested blocks would increase the volume error. On the contrary, gradual change in the mesh size between consecutive blocks should improve accuracy and convergence. As MC pointed out, make sure each nested block fits within fixed mesh points in the containing block and the ratio of mesh size between any two adjacent blocks does not exceed 2.

ivan February 17, 2009 10:50

Re: Meshing - Nested mesh block *NM*

All times are GMT -4. The time now is 00:52.