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-   -   scale of mesh (https://www.cfd-online.com/Forums/fluent/139187-scale-mesh.html)

hassanmaleki July 18, 2014 17:44

scale of mesh
 
Hi

If I reduce the scale of my mesh(Ex, from m to cm or mm), Can I increase the speed of convergence's process? or It's unhelpful? :confused: :D

Best regards,
Hassan

malay July 19, 2014 08:20

That's depends on your case . if you scale from m to mm may be you go from normal scale to macro scale and that's mean different case

hassanmaleki July 19, 2014 14:20

Hi ahmad

First Thanks for your comment,
But I did n't understand exactly! Can you explain more? ;)
I have a 3d mesh in m scale and I want replace it's scale with cm or mm for increase speed!

Best regards,
Hassan

malay July 19, 2014 15:30

Quote:

Originally Posted by hassanmaleki (Post 502291)
Hi ahmad

First Thanks for your comment,
But I did n't understand exactly! Can you explain more? ;)
I have a 3d mesh in m scale and I want replace it's scale with cm or mm for increase speed!

Best regards,
Hassan

firstly I think you mean overall simulation time by "speed" ?is it ?
secondly , when you scale case from m to mm ( as example ) that's mean you mesh a case on mm dimension not on m dimension , so that is different cases ?
thirdly what is your case dimensions ?

Far July 20, 2014 12:55

Quote:

Originally Posted by hassanmaleki (Post 502203)
Hi

If I reduce the scale of my mesh(Ex, from m to cm or mm), Can I increase the speed of convergence's process? or It's unhelpful? :confused: :D

Best regards,
Hassan

No....

On the contrary if it is non-physical you will expereince divergence or very slow convergence...

hassanmaleki July 20, 2014 14:16

Hi
Thank you Ahmad and Sijal!

I simulate air flow in a room and I have 3d mesh! but convergence process is very slow!

so,according what you said this work is not helpful and maybe divergence!:(

Best Regards,
hassan

Far July 20, 2014 14:34

Quote:

Originally Posted by hassanmaleki (Post 502356)
Hi
Thank you Ahmad and Sijal!

I simulate air flow in a room and I have 3d mesh! but convergence process is very slow!

so,according what you said this work is not helpful and maybe divergence!:(

Best Regards,
hassan

Why you want to scale your mesh?

Usually it is done to get the units to which model is drawn.

May be if you are studying some wind tunnel model and want to replicate that experiment then you choose this option, but in that case you need to change your boundary conditions...

ghost82 July 21, 2014 16:36

In a few words, if you scale down the model with the mesh you have a different geometry and results will be different, with same boundary conditions.
You need to simulate the real geometry and adapt the mesh to your needs.
If you have the real geometry and you are asking for reducing only the mesh size, then in general convergence could be better, but maybe you have to change wall function.


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