FDS 5 to FDS 6 input file

[Mark McAuliffe]

Hi,

I am working on modifying an input file that ran in FDS 5 to run in FDS 6. The input file I am using gets stuck on the &PART command. From looking at the version 5 user guide it looks like it is calling out "TREE" as a special type of particle. I couldn't find anything in either the FD5 or 6 user guide that showed how to correctly input for this type so I am not sure what I need to modify to get it to work in FDS 6.

This is the section of the input file where the simulation stops:

&PART ID='EXCELSIOR',TREE=.TRUE.,QUANTITIES='VEG_TEMPERATURE',
VEG_INITIAL_TEMPERATURE=22,
VEG_SV=4000.,
VEG_MOISTURE=0.07,
VEG_CHAR_FRACTION=0.154,
VEG_ASH_FRACTION =0.0035
VEG_DRAG_COEFFICIENT=0.125,
VEG_DENSITY=400,
VEG_BULK_DENSITY=3.13,
VEG_BURNING_RATE_MAX=0.35,
VEG_DEHYDRATION_RATE_MAX=0.35,
VEG_DEGRADATION = 'LINEAR',
VEG_CHAR_OXIDATION = .FALSE.,
VEG_REMOVE_CHARRED=.TRUE. /
&TREE XB=0.0,1.3,-0.4,0.4,0,0.1,PART_ID="EXCELSIOR",FUEL_GEOM="RECTANGLE",
OUTPUT_TREE=.TRUE.,LABEL='excelsior' /

Any advice would be greatly appreciated.

Thanks,
Mark

[Kevin]

This input line is a good example for why we had to change things in FDS 6. By the time FDS 5 was developed, the code had become bloated with subject-specific parameters for vegetation, electrical cables, warehouse commodities, and so on, because of the various projects that the FDS developers and others had worked on over the years. These various sets of parameters and routines added thousands of extra lines of code and were essentially redundant. So in FDS 6, we developed a more general pyrolysis model that could be used to describe a vast variety of different materials. We no longer use "VEG" parameters, and we no longer input a TREE with its own special line. 

Take a look at the cases found here

https://github.com/firemodels/fds/tree/master/Validation/NIST_Douglas_Firs/FDS_Input_Files

This is how we model pine trees in the latest version of FDS. Run a case, and then take a look at the inputs. They are all explained in the User's Guide, but it is sometimes hard to understand from the User's Guide how it all fits together. Hence the example cases. If you have further questions, post them here.

[Mark McAuliffe]

Ok, I will take a look. Thanks!

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[Mark McAuliffe]

Hi,

I am still working on converting this file. To make the input file for version 6 run as similar as possible to version 5 I would like to know exactly what the subject-specific parameter: "tree" created as inputs.

Is there any way to get his information so I can recreate the exact inputs in the general pyrolysis model?

Thanks,
Mark

[Ruddy]

Mark,

There should be enough in the FDS user guide and example input files for you to make the transition. But, if you need more help (it is somewhat confusing) let's take this off the discussion page. Please send me the original input file you are trying to convert.

Ruddy

On Wednesday, August 15, 2018 at 10:47:15 AM UTC-7, Mark McAuliffe wrote:

Hi,

I am still working on converting this file. To make the input file for version 6 run as similar as possible to version 5 I would like to know exactly what the subject-specific parameter: "tree" created as inputs.

Is there any way to get his information so I can recreate the exact inputs in the general pyrolysis model?

Thanks,
Mark

On Wednesday, August 8, 2018 at 7:13:02 AM UTC-7, Mark McAuliffe wrote:

Ok, I will take a look. Thanks!

On Wed, Aug 8, 2018 at 7:11 AM, Kevin <mcgr...@gmail.com> wrote:

This input line is a good example for why we had to change things in FDS 6. By the time FDS 5 was developed, the code had become bloated with subject-specific parameters for vegetation, electrical cables, warehouse commodities, and so on, because of the various projects that the FDS developers and others had worked on over the years. These various sets of parameters and routines added thousands of extra lines of code and were essentially redundant. So in FDS 6, we developed a more general pyrolysis model that could be used to describe a vast variety of different materials. We no longer use "VEG" parameters, and we no longer input a TREE with its own special line. 

Take a look at the cases found here

https://github.com/firemodels/fds/tree/master/Validation/NIST_Douglas_Firs/FDS_Input_Files

This is how we model pine trees in the latest version of FDS. Run a case, and then take a look at the inputs. They are all explained in the User's Guide, but it is sometimes hard to understand from the User's Guide how it all fits together. Hence the example cases. If you have further questions, post them here.

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