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Creating zones?

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Re: Creating zones?

Posted by Patti Sheaffer at March 07. 2017

Sorry - it cut me off (a script thing).

I need to define a couple of zones on a grid, so that I can do conjugate heat transfer between fluid and solid.  I'm wondering what the standard Salome way to declare a "zone" which will be picked up by CFD software into which I will import the grid?

Thank You!!

PattiM

Re: Creating zones?

Posted by Saint Michael at March 07. 2017

Hi

The standard way is:

1) in Geometry module, specify sub-shapes defining a zone. Either by creating a group or by doing New Entity > Explode.

2) In Mesh module, create a group ( == zone) on the sub-shapes using Mesh > Create Groups from geometry.

St.Michael

Re: Creating zones?

Posted by Patti Sheaffer at March 07. 2017

Thank you very kindly for the reply.  I create surfaces and volumes with "Explode."  This much works well.  I will try creating groups - does this zonal information get included in the CGNS file which I export?  If so, my CFD software may not be reading the CGNS file correctly.

Best,

Patricia

Re: Creating zones?

Posted by Patti Sheaffer at March 07. 2017

I wanted to check my procedure.  In the geometry module, I create a sphere inside a box (representing a cannon ball in a fluid domain), and make a partition out of this.  I explode on both "solids" and "faces."  The solids are the liquid and solid zones, is that correct?

Now, in the mesh module, I create a new mesh and temporarily say it's Netgen-123.  I select the mesh in the left-hand window, then Mesh > Create Groups from geometry, and add the face and volume objects for the cannon ball, select Apply and Close.

It has "Group of Faces" and "Group of Solids" entries.  Would this, then, be the "zone" for the CFD calculation to do the solid heat transfer calculations?

What's also critical is the point-to-point match-up of the grids in the two zones which meet at the surface of the cannonball.  I'm not sure how this consideration affects the gridding calculation.  I'm also not sure to which zones the cannonball surface belongs (both zones?).

Thank You Very Much.

Re: Creating zones?

Posted by Patti Sheaffer at March 08. 2017

So, starting from scratch, I have two nested cubes - the inner cube should be grid zone 1 (block 1), and the outer cube should be grid zone 2 (block 2).  I plan to export the grid to a CGNS file.  The faces have been exploded (you can see in the tree view to the left).  I will try defining zones in the next post (in the grid module).

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Re: Creating zones?

Posted by Patti Sheaffer at March 08. 2017

I'm very sorry, my previous post was wrong - here is the model: two nested box zones exploded on two volumes (the two blocks/zones) with faces.

Re: Creating zones?

Posted by Patti Sheaffer at March 08. 2017

I believe this is correct, and ready for exporting the CGNS grid, according to the procedure mentioned.  For some reason when I import the CGNS file into my CFD software, it does not recognize these as two distinct zones (blocks).  It may be because "zones" or "blocks" have different ways they can be defined in the CGNS standard.

Thank You Very Much!

Patricia

Re: Creating zones?

Posted by SMESH expert at March 09. 2017

Hello Patricia

In SALOME, the whole mesh is exported as a CGNS zone. So, I think it's impossible to define several CGNS zones using SALOME.

It's possible to export several meshes into one CGNS file, but each mesh is exported as a separate CGNS base and not as a new zone in a CGNS base.

Best regards

Edward

Re: Creating zones?

Posted by Patti Sheaffer at March 09. 2017

Thank  you very much for the information!  Have a great weekend.

 

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