Questions about Validation Output in CFAST (for 7.6.0 and 7.7.4)
Joel Lederfind
Hello,
I have some questions about the validation output in CFAST. My group is currently running CFAST 7.6.0 as or V&V’d version, but I have also noted these same behaviors in the current release of CFAST 7.7.4.
Per the User Guide (pg. 44, in either version), if validation output is checked, the program is directed to output abbreviated headings for the spreadsheet outputs. So far, I have not noticed any of the spreadsheet column headings changing when the validation output it turned on or off. Is that still a feature of the program?
There was a discussion in the CFAST users group back on Jul 12, 2019 about the validation output option, it mentioned that the net heat flux output was modified to be consistent with water cooled gauges. Checking the “Target Net Flux” column with validation output on and off, I notice no difference between the 2 net fluxes (other than the additional 6 digits added to the number in validation mode). This is the same for both 7.6.0 and 7.7.4. It looks like that older discussion was for CFAST 7.3.1. Since then to versions 7.6.0 – 7.7.4, was there a change made to what the validation output box effectively does to the results? I do note that there is the separate “Target Total Gauge Flux” column included with the validation outputs, is that was being referred to in the discussion?
Ultimately, we are trying to answer the question of whether or not validation output should be left on when running analyses beyond just V&V cases. Are there any other changes that turning on validation output makes to the program and its outputs that could affect results or cause them to differ from cases where validation output is off? Similar to what was discussed in the older users group question, the User Guide doesn’t say much. Our current stance is that it should be left off when performing calculations. But having the additional information it adds to the devices output sheet (particularly for the breakdown of fluxes contributing to the incident and net flux) has been helpful information for some cases we are looking at.
I also had a strange issue show up as I was doing a few tests this morning with and without validation output, where checking or unchecking the box in the cEdit GUI made no effect on the spreadsheet output at all. I tried restarting and using new input files several times, both with CFAST 7.6.0 and 7.7.4, and it always had the validation output on. This was a new occurrence, as I was able to change this and see the expected outputs a few days ago but using only the GUI. Is there something known that could cause the program to hang up like this and not take changes made in the GUI and apply them to the run? I had to run using the command prompt to get around this issue and get the program to show results without validation output.
Any help or info is appreciated, thanks!
Joel Lederfind
