Modeling Deciduous Trees in FDS Wildfire Simulations

[jwolf-fire]

I am using the [Crown Fires]((https://github.com/firemodels/fds/tree/master/Validation/Crown_Fires) example file as a starting point for my wildfire modeling. In this file (and in most other examples I have been able to find) it appears that a particle-based approach with the generic vegetation pyrolysis model is used to represent pine trees.

I am wondering if anyone has advice on modeling deciduous trees in a similar way, specifically with respect to:

1. Defining geometry: The conical particle representation seems well suited for pine trees, but none of the standard FDS shapes appear to accurately represent an oak tree or similar deciduous species.
2. Material and surface properties: Recommendations for selecting parameters such as the pre-exponential factor (A), activation energy (E), surface-to-volume ratio, and characteristic length.

I have attached the current input file I am using for testing, should that be helpful for context.

260120_random.txt

[ericvmueller]

For geometry, you can piece together many cells containing particles (or voxels) to create your tree crown geometry. This can either be done 'by hand' with many small INIT blocks, or with a single file that defines the geometry for a single tree or the whole canopy: https://github.com/firemodels/cad/tree/master/Case_Studies/Binary_Bulk_Density_File

For material properties, if you cannot measure them yourself then you will need to consult the literature to see what has been reported for your species or similar.

[jwolf-fire]

Thank you!

[jwolf-fire]

As a follow up, how can I create the bulk density data file (.npy) as shown in this example?

[ericvmueller]

check out the script that was used to create the file
https://github.com/firemodels/cad/blob/master/Case_Studies/Binary_Bulk_Density_File/create_bulk_density_file.py

You will see a chunk of code that you would need to modify. Rather than reading in the array of data in bd_data.npy, you would pull in or generate your own data. This is a 3d array that defines the bulk density values at the center of cubic voxels. Voxel sizes/locations are defined by the xv, yv, zv arrays.