CHANGING REFERENCE SYSTEM

Numerical methods and mathematical models of Elmer
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Andrea_P
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CHANGING REFERENCE SYSTEM

Post by Andrea_P »

Good evening,
I am trying to change the reference coordinate system to adapt it to my case's one, but I don't know how to do it. I attached my case's image.
Thanks in advance for your help.
-Andrea
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sitema_di_riferimento.jpg
sitema_di_riferimento.jpg (13.59 KiB) Viewed 280 times
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raback
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Re: CHANGING REFERENCE SYSTEM

Post by raback »

Hi

Could you be more specific. What coordinate system are you looking for? For most solvers the selection is limited to cartesian 2D/3D and axially symmetric.

-Peter
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Re: CHANGING REFERENCE SYSTEM

Post by Andrea_P »

raback wrote: 05 Jun 2021, 19:45 Hi

Could you be more specific. What coordinate system are you looking for? For most solvers the selection is limited to cartesian 2D/3D and axially symmetric.

-Peter
Hi Peter,
My system is 2D and I am trying to use that of the image.
-Andrea
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Andrea_P
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Re: CHANGING REFERENCE SYSTEM

Post by Andrea_P »

I am trying to change the coordinate system used a priori in Elmer in that one of the image. I thought to put a sign minus before the numbers in the code line:

Code: Select all

Coordinate mapping(3) = -2 -1 3
Nevertheless, this action is wrong.
Regards,
Andrea
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Andrea_P
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Re: CHANGING REFERENCE SYSTEM

Post by Andrea_P »

raback wrote: 05 Jun 2021, 19:45 Hi

Could you be more specific. What coordinate system are you looking for? For most solvers the selection is limited to cartesian 2D/3D and axially symmetric.

-Peter
The used domain in Elmer is in the attached image, so as you can see, it is different form that one of reference.
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Screenshot at 2021-06-06 12-41-10.png
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raback
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Re: CHANGING REFERENCE SYSTEM

Post by raback »

Hi

Mathematically these systems are the same so I don't really get the point. You can rotate the picture you attached and look it through mirror to make it follow the standard conventions. Likewise for post-processing you can rotate and mirror the results in Paraview as you like. It does not change the field values.

There are no benefits from leaving the standard conventions of coordinate system. For example, the sign of the cross product depends on agreement and it would bring no added value to leave the choice of r-h-s vs. l-h-s coordinate system to the user.

-Peter
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Re: CHANGING REFERENCE SYSTEM

Post by Andrea_P »

raback wrote: 06 Jun 2021, 15:28 Hi

Mathematically these systems are the same so I don't really get the point. You can rotate the picture you attached and look it through mirror to make it follow the standard conventions. Likewise for post-processing you can rotate and mirror the results in Paraview as you like. It does not change the field values.

There are no benefits from leaving the standard conventions of coordinate system. For example, the sign of the cross product depends on agreement and it would bring no added value to leave the choice of r-h-s vs. l-h-s coordinate system to the user.

-Peter
Thanks, Peter, it is like I was thinking. Hence, I will check in Paraview a way to do a "mirror".
-Andrea
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