Numerical Instability using CO2 supply vent and water mist nozzle

[GoogleCodeExporter]

Application Version: 5.3.0 Serial
SVN Revision Number: 3193
Compile Date: 30 Jan 2009
Operating System: Windows XP Professional SP 2

Describe details of the issue below:

Hi,

I'm encountering numerical instability for an FDS simulation set up using
Pyrosim (Revision 2008.2.1113). The simulation contains a burner fire with
specified heat release rate. I've also defined a reaction and material
properties for the fire. I have a single nozzle water sprinkler, and a
single obstruction with a vent attached to the lower (Z-) surface. The vent
emits CO2. I've attached the model file which should run in less than a
minute on most machines.

When I run the simulation without the sprinkler nozzle, it runs fine. When
I run it without the CO2 vent, it runs fine. When I run the simulation with
both the nozzle AND the CO2 vent activated, the simulation crashes very
shortly after the CO2 vent is activated. The nozzle can be activated at any
stage in the simulation with no issues.

Has anyone come across similar errors or can offer some advice? Apologies
if this has been answered before - I didn't see anything on the forums and
have looked hard through the FDS and Pyrosim User Manuals.

Thanks!

Matt

Original issue reported on code.google.com by mattjfit...@gmail.com on 22 Jul 2009 at 4:57

Attachments:

• test14.fds

[GoogleCodeExporter]

Try it with 5.3.1 and let me know if it changes anything.

Original comment by mcgra...@gmail.com on 22 Jul 2009 at 12:21

• Changed state: MoreInfo

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I was able to run the simulation when using 5.3.1. Thanks for the advice!

Original comment by mattjfit...@gmail.com on 26 Jul 2009 at 10:40

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Great! Thanks for letting me know.

Original comment by mcgra...@gmail.com on 27 Jul 2009 at 11:37

• Changed state: Verified

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i have pyrosim model 2010.2 and fds 5.5 and i am performing wind analysis of a 
large area. The problem that i am facing is after 6.5 seconds it gives 
numerical instability.Another problem that i am facing is that when i import a 
.DXF file from Ecotect it shows in pyrosim but the roofs of the model are 
missing.Does anyone have any idea about how to add roofs to the model. I am 
attaching the fds file of the model. Thanks in advance.

Original comment by rishabh....@gmail.com on 28 Sep 2011 at 10:28

Attachments:

• untitled.fds

[GoogleCodeExporter]

We do not address PyroSim questions in this forum. As for the instability, 
start a new thread. The current thread is closed. When you start the new issue, 
submit a simplified test case that demonstrates the problem. We cannot debug a 
file with 4500 lines.

Original comment by mcgra...@gmail.com on 28 Sep 2011 at 12:57