# scale of mesh

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 July 18, 2014, 16:44 scale of mesh #1 New Member   hassanmaleki Join Date: May 2014 Location: Dubai Posts: 16 Rep Power: 3 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? Best regards, Hassan

 July 19, 2014, 07:20 #2 Member   ahmad Join Date: Feb 2012 Posts: 96 Rep Power: 5 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

 July 19, 2014, 13:20 #3 New Member   hassanmaleki Join Date: May 2014 Location: Dubai Posts: 16 Rep Power: 3 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

July 19, 2014, 14:30
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 Originally Posted by hassanmaleki 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 ?

July 20, 2014, 11:55
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Sijal Ahmed Memon (turboenginner@gmail.com)
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Quote:
 Originally Posted by hassanmaleki 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? Best regards, Hassan
No....

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

 July 20, 2014, 13:16 #6 New Member   hassanmaleki Join Date: May 2014 Location: Dubai Posts: 16 Rep Power: 3 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

July 20, 2014, 13:34
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Sijal Ahmed Memon (turboenginner@gmail.com)
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Quote:
 Originally Posted by hassanmaleki 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...

 July 21, 2014, 15:36 #8 Senior Member     Daniele Join Date: Oct 2010 Location: Italy Posts: 949 Rep Power: 15 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. eaalaei likes this.

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