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 on: December 19, 2018, 08:18:28 am 
Started by Avdbrum - Last post by Avdbrum
Hi all,
I'm using the latest update of Pyrosim (2018.3.1210) and noticed something very strange. For parallel running of the simulation I divided the mesh in multiple meshes and noticed that Pyrosim appears to create a physical wall in some of the boundaries between meshes. I noticed a post from Tenzing in 2013 where the same phenomena is described, but back then the issue was supposedly fixed with a new update. Is there anyone else who encountered the issue as well?

 on: December 17, 2018, 05:42:55 am 
Started by marferit - Last post by marferit
Thanks a lot

 on: December 16, 2018, 09:16:59 am 
Started by Jahid - Last post by Dave McGill
Here's the short version,

Model ->Edit Reactions -> Add from Library -> pick one of them


 on: December 15, 2018, 11:26:06 pm 
Started by Jahid - Last post by Jahid
''a reaction must be defined in order to simulate burning in fds problem''

how to solve this??

 on: December 14, 2018, 10:36:20 am 
Started by agro - Last post by Jon Albrecht
It means that the FDS solver was unable to arrive at a solution to the problem you provided it. Without seeing your model, it is impossible to know the problem. PyroSim simplifies the use of FDS, but it does not absolve the user of responsibility for not understanding the underlying solver. I encourage you to spend some time reading through both the FDS User's Guide, and the FDS Technical Reference. If you are not at all familiar with the solver, it is also worth noting that Thunderhead Engineering hosts trainings on PyroSim and FDS for those who prefer an instructor to guide their learning process. You can send an email to for guidance on your problem.


Jon Albrecht
Thunderhead Engineering

 on: December 14, 2018, 10:29:04 am 
Started by marferit - Last post by Jon Albrecht

The most common way to handle this would be to specify devices at the locations where you are attempting to measure output.

If you need output as represented by slices, boundary files, or plot3d files, the best way to convert the output to numerical data is to use a tool provided by the team at NIST.

If you go to your PyroSim install folder, and then the fds folder within, there will be a tool called fds2ascii. While we don't explicitly provide support on how to use it, the FDS User guide provides some documentation on the tool.

Hope that helps!


Jon Albrecht
Thunderhead Engineering

 on: December 14, 2018, 07:50:22 am 
Started by agro - Last post by agro
Please answer
Thank you

 on: December 14, 2018, 07:48:44 am 
Started by agro - Last post by agro
Smokeview did not finish the simulation. He gave the following error:

STOP: Numerical Instability (CHID: namefile)

What does it mean?

 on: December 14, 2018, 07:17:52 am 
Started by agro - Last post by Dave McGill

Ensure that the surface of the solid obstruction and the plane of the vent line up with the mesh, and that the vent doesn't extend over the edge of the obstruction or extend into another obstruction.


 on: December 13, 2018, 10:51:32 am 
Started by marferit - Last post by marferit
   I am learning to use pYrosim for a few days , but I do not understand how to extract the results (temperature, air velocity and pressure) as numerical values at each time step for each point of the mesh (or for a small area). For example, I can create sections, and in the post processing  I can see the results in these. but how can I get the results in table format?
Thank you

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