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viscous layer on surface inside partition

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viscous layer on surface inside partition

Posted by Chaz at March 17. 2012

Hello,

I am having quite a bit of difficulty with the viscous layer feature.

In order to model both solid and fluid regions, such as with openfoam, my understanding is that I need to build models with different regions using partitions.

In my partition, I need a viscous layer against the internal boundary face of the mesh.  Is this possible?  Does the viscous layer feature only work for faces that are on the outside boundary of the mesh domain?  All the examples I can find only show viscous layers on the outside faces.

 

Thank you,

 

Re: viscous layer on surface inside partition

Posted by Saint Michael at March 19. 2012

Hello,

you are right, viscous layers can't be created on internal faces of a model. A possible workaround is following:
1) Create a geom model using partition.
2) Mesh the solid part with viscous layers separately from the fluid part. Create a group (group on geometry) of 2d mesh elements laying on the boundary faces between the fluid and solid parts.
3) Mesh the fluid part. To mesh the boundary faces use "Use existing 2D elements" algorithm with Source Faces = <a group of 2d elements> and option "To copy mesh"=True. Thus two meshes will be united.

St.Michael

Re: viscous layer on surface inside partition

Posted by Saint Michael at March 19. 2012

Saying "to mesh separately" I mean creating a mesh for a solid part and another mesh for a fluid part.

Re: viscous layer on surface inside partition

Posted by Chaz at March 19. 2012

Thank you, I will try that!

Re: viscous layer on surface inside partition

Posted by Saint Michael at April 12. 2012

Here is a script making what I meant. It creates viscous layers on internal faces of 3 boxes.

St.Michael

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Re: viscous layer on surface inside partition

Posted by Chaz at April 12. 2012

Thank you, I will look into the approach used in the python script.

I have also looked into Hexotic as a solution for this issue.  It looks Hexotic has the capabilities to add boundary layers on internal surfaces between domains.  However, that capability is in a very new stand-alone version, but not available as a plug in with Salome (yet?).  It appears to require a surface mesh first, therefore I would have to make a surface mesh in Salome, export, mesh in Hexotic, then convert that mesh for the solver I'm using (openfoam).

Any idea how to get a mesh from Salome to work with a .mesh or .meshb format, that is required by Hexotic?  I am unable to find much info on conversion from unv or med to .mesh...

Re: viscous layer on surface inside partition

Posted by Saint Michael at April 13. 2012

Hello

.mesh format is very simple and is described in Hexotic User Manual. So it's not so hard to write a python script that would write 2D mesh computed by SALOME into a .mesh file.

Another solution is to catch an input tmp file SALOME generates for Hexotic before it is removed. I would open such a file in emacs and then store it in a safe place.

 

St.Michael

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Activate by Chaz on Mar 17, 2012 05:55 AM
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