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-   -   Odd mesh in aerofoil (http://www.cfd-online.com/Forums/star-ccm/110094-odd-mesh-aerofoil.html)

bean December 3, 2012 17:54

Odd mesh in aerofoil
 
1 Attachment(s)
Hi all,

I have attempted to mesh a box around a naca aerofoil to simulate the flow field. However, when I try to refine the mesh it creates odd parts inside the aerofoil. Im pretty sure it isnt the CAD as i have it working on another simulation.

The only problem that I thought it might be is because I said to use Prism layers but it hasnt put any on.

I have attached a picture with the weird mesh, and any thoughts as to why that is happening or why the prism layers arent showing up would be really helpful, thanks!

lava12005 December 4, 2012 21:59

Try to reduce the surface cell size maybe?
You can try to do the surface mesh first (no need to perform the volume mesh) and then see how does the mesh looks like. You can also post the picture here.
It might be that the surface mesh representation is not good so that it creates a bad volume mesh

bean December 8, 2012 18:49

Thank you for your reply, unfortunately changing the surface mesh first doesnt seem to help. The problem seems to happen as I refine the mesh. if i have a fairly coarse mesh, giving a crude outline of the aerofoil it is fine, and then as i refine it, it gives these weird shapes (shown in above picture). if I then make it coarse again, they go away-or at least get a lot better.

Any thoughts would be appreciated! Thank you

shyam88 December 9, 2012 07:24

maybe try and add contact prevention?

bean December 9, 2012 12:31

Hi Shyam 88,

How would I do that please?

Thank you

shyam88 December 9, 2012 13:30

regions > air > mesh values > contact prevention, right click new, one group contact prevention.

select boundaries, ie airfoil
search floor - make it really small in comparison to your mesh size.

bean December 13, 2012 16:54

Hi,

thanks thats great. Thanks for your help


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