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Author Topic: Meshes Alignment  (Read 3906 times)

wilsonobre

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Meshes Alignment
« on: April 20, 2015, 06:50:36 am »

Hi Everyone!
I get this message "ERROR: MESH   2 is out of alignment with MESH   1" when I run the simulation! But when I setup my mesh the "Mesh Alignment says that the alignment is fine "passed"!  I'm using this version of PyroSim [2014.2.0807] fds version 6.1.0!
I sent my model in attachments, together with 2 images of those messages

Wilson
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swenson

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Re: Meshes Alignment
« Reply #1 on: April 20, 2015, 08:20:23 am »

Wilson,

These meshes are clearly not aligned and PyroSim should have given you a warning message. You can see the mesh alignment constraints discussed either in the PryoSim User Manual or the FDS User Manual. To open, on the PyroSim Help menu, click PyroSim Manual or More Help.

The quick fix is for you to align the meshes. Since your model does not have very many cells, my recommendation is to just keep the same cell size in both meshes. I have done that in the attached model.

I will submit this as a bug to be fixed in PryoSim.

Thanks,
Daniel Swenson
Thunderhead Engineering
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Bryan Klein

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Re: Meshes Alignment
« Reply #2 on: April 20, 2015, 03:40:06 pm »

Also, please make sure that you are using the most recent version of PyroSim.
http://www.thunderheadeng.com/pyrosim/download/

-Bryan
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wilsonobre

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Re: Meshes Alignment
« Reply #3 on: April 21, 2015, 05:57:29 am »

Thanks guys! I'll check It Mr. Klein, Thank you!
A question Mr.Swenson: In this case  if I'm doing a Grid Sensitivity Analysis, you advise me to do in  both meshes?
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swenson

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Re: Meshes Alignment
« Reply #4 on: April 23, 2015, 01:26:28 pm »

Wilson,

The mesh alignment check bug has been fixed and will be in the next PyroSim release. The problem was that at about the sixth decimal place, the meshes actually had a gap between them so the alignment test assumed the meshes were independent and did not test for alignment. I would suggest that you input the mesh coordinates by typing in exact numbers, not using the mouse.

As far as refinement studies, you can either vary both meshes or just the one with the fire. Use the D* calculator (spreadsheet on our web to find the mesh size requirement for the  fire).

Daniel Swenson
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