Numerical instability

[GoogleCodeExporter]

I have run into a problem where the addition of sprinklers to a house 
appears to be causing a numerical instability.  I am modeling a small 
house.  With no forced flow, the simulation runs without issue.  When I 
add the DEVC, PROP and PART lines to include sprinklers, a numerical 
instability occurs within the first 5 seconds.  In viewing vector slices, 
there appear to be relatively high velocities near some of the walls.  Any 
ideas about why this is occurring?

Original issue reported on code.google.com by spf...@gmail.com on 17 May 2007 at 8:51

Attachments:

• RANCHTEST_PF_TEST4.FDS

[GoogleCodeExporter]

I just confirmed with Paul that this is RC4.
He is going to simplify the case and resubmit another input file.
-Bryan

Original comment by bryanwkl...@gmail.com on 17 May 2007 at 8:59

[GoogleCodeExporter]

another user has reported something similar in the discussion group.  it 
appears to 
be a problem in the interaction between drops and the walls.  

Original comment by drjfloyd on 18 May 2007 at 4:17

• Changed state: Started
• Added labels: Priority-High
• Removed labels: Priority-Medium

[GoogleCodeExporter]

In making changes to the droplet tracking we were resetting one of the wall 
tracking 
arrays to zero in the wrong place while looping over droplets.  As a result 
overly 
large amounts of heat transfer to the walls was being computed which was the 
root 
cause of the instability.

Original comment by drjfloyd on 18 May 2007 at 3:31

• Changed state: Fixed

[GoogleCodeExporter]

This issue has been duplicated with Issue 48 

Original comment by drjfloyd on 27 Jun 2007 at 1:32

• Changed state: Duplicate