A simplified model to incorporate firebrand transport into coupled fire atmosphere models

Alberto Alonso-Pinar; Jean-Baptiste Filippi; Ha-Ninh Nguyen; Alexander Filkov

doi:10.1071/WF24200

RESEARCH ARTICLE (Open Access)

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A simplified model to incorporate firebrand transport into coupled fire atmosphere models

Alberto Alonso-Pinar

^A ^B ^* , Jean-Baptiste Filippi

^A , Ha-Ninh Nguyen

^A ^B and Alexander Filkov

^B

+ Author Affiliations

- Author Affiliations

^A SPE UMR6134, Université de Corse, Campus Grossetti, Corte, France.

^B Faculty of Science, The University of Melbourne, 4 Water Street, Creswick, VIC, Australia.

^* Correspondence to: aalonsopinar@student.unimelb.edu.au, alonso-pinar_a@univ-corse.fr

International Journal of Wildland Fire 34, WF24200 https://doi.org/10.1071/WF24200

Submitted: 26 November 2024 Accepted: 10 June 2025 Published: 7 July 2025

© 2025 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of IAWF. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)

Abstract

Background

During wildfires, vegetation elements can be ignited and detached leading to the generation of firebrands. These firebrands can be lifted by the fire plume, transported far away from the main fire, and ignite new fires – a phenomenon known as fire spotting. Recently, numerical simulations of fire spotting using coupled fire–atmosphere models have provided insights on the role of different components of the phenomena such as fire intensity and turbulence. However, current fire propagation models do not account for long-range spotting distances.

Aim

This study aims to develop a medium and long-range firebrand transport model that can provide firebrand trajectories under the numerical and time constraints of a coupled fire–atmosphere model.

Methods

A computationally efficient transport model for calculating firebrand transport is proposed. This model is evaluated against more complex models incorporating drag and lift coefficients, and combustion models.

Key results

The reduced model accurately replicates firebrand landing patterns for both simple and complex topographies.

Conclusions

The proposed transport model represents firebrand landing patterns with a reduced computational time by a factor of 7, when compared to the more complex model.

Implications

Using the proposed model, spotting phenomena can be integrated within coupled fire–atmosphere models and thereby improve fire management.

Keywords: combustion, fire–atmosphere modelling, firebrand, long-range spotting, spotting, turbulence, reduced model, wildfire.

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