# NFSDM

**Repository Path**: mirrors_LLNL/NFSDM

## Basic Information

- **Project Name**: NFSDM
- **Description**: This is a python code to simulate the formation and evolution of particles in an airburst as a homogeneous fireball expands and cools. The numerical model applied is a Lagrangian particle super-droplet method.
- **Primary Language**: Unknown
- **License**: MIT
- **Default Branch**: main
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2022-09-10
- **Last Updated**: 2026-01-03

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

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Nuclear Fallout Super-droplet Method (NFSDM)"
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This is a python code to simulate the formation and evolution of particles in an airburst as a homogeneous fireball expands and cools. The
numerical model applied is a Lagrangian particle super-droplet method. This work has been published: D. L. McGuffin, D. D. Lucas, J. P. Morris, G. D. Spriggs, K. B. Knight. (2022) "Super-droplet Method to Simulate Lagrangian Microphysics of Nuclear Fallout in a Homogeneous Cloud" *Journal of Geophysical Research: Atmospheres 127* (18) [doi:10.1029/2022JD036599](https://doi.org/10.1029/2022JD036599).

Running the model
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To run the model, call wrapper.py from the command line with inputs: ( maximum time (sec), Yield (kt), Mass (kg), scaling factor applied to condensation and nucleation rates (-), scaling factor applied to coagulation kernels (-), string of species name (FeO, SrO), path to directory to save data )
Example:
$ python -u wrapper.py 60 10 1500 1 1 FeO /path_to_save_directory/

Description of routines
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The wrapper.py calls main.py, which starts the master time loop. Inside a master time loop condensation, nucleation, and coagulation are simulated. The respective py files contain the code to perfom each process, and do_microphysics.py calls the condensation.py, nucleation.py, and coagulation.py.
Additionally, adapt_superdroplets.py is used to merge super-droplets. Sizedist.py and figs.py are used to convert between super-droplets and real particle size distribution, and to create figures, respectively. Cooling.py includes the boundary conditions for the cloud expansion and cooling. Thermo_properties.py includes dictionaries for the thermodynamic properties of SrO and FeO.

Dataset
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A model-generated dataset utilized to create figures in (McGuffin, D. L. et al., 2022) is archived in fallout_superdroplet_output.tar.gz and described in [SDM_Dataset.pdf](https://github.com/LLNL/NFSDM/blob/main/SDM_Dataset.pdf).


License
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The code is distributed under the terms of the MIT license.

All new contributions must be made under the MIT license.

See [LICENSE](https://github.com/LLNL/NFSDM/blob/main/LICENSE) and [NOTICE](https://github.com/LLNL/NFSDM/blob/main/NOTICE) for details.

SPDX-License-Identifier: (MIT)

LLNL-CODE-839524