Session: 08-12-01: Optimization, Uncertainty and Probability

Paper Number: 164986

Simulating Trajectory of Flying Embers in Wildfires Accounting for Convective Boundary Layer Effects 

Wildfires pose a significant threat to both natural ecosystems and

human infrastructure, and fire residues play a crucial role in the prop-

agation of secondary ignitions. These fire residues, commonly referred

to as firebrands or embers, can be transported over considerable dis-

tances by a combination of horizontal wind shear within the atmo-

spheric boundary layer and the convective forces generated by the fire

itself. Understanding the mechanisms governing ember transport is

essential for improving wildfire prediction models and developing ef-

fective fire mitigation strategies. Since embers can ignite new fires far

from the primary combustion zone, accurately modeling their trajec-

tory is critical to anticipating fire spread and implementing proactive

preventive measures.

The objective of this study is to investigate the dynamics of ember

transport through numerical simulations, focusing on the key physical

parameters that influence the motion of the ember. The research will

first analyze the vertical component of the ember trajectory, which 

is predominantly governed by buoyancy and convective uplift forces.

Isolating the vertical motion at this stage allows for a detailed exam-

ination of the fundamental aerodynamic principles without the added

complexity of horizontal wind transport. Following this initial analysis,

the study will be extended to incorporate horizontal wind flow effects,

recognizing that wind-driven ember transport is a primary mechanism

behind long-range fire s pread. However, in this preliminary investi-

gation, turbulent wind fluctuations will be neglected to focus on the

dominant aerodynamic forces that affect ember motion.

Probability method will be used to examine the random variation of

mass, enhanced by the burning process, on the trajectory of the embers.

The anticipated results of this research include a more compre-

hensive understanding of the governing transport mechanisms and the

development of a predictive framework to estimate the ember trajec-

tories. By refining the accuracy of the ember dispersion models, this

study aims to contribute to the enhancement of wildfire simulation

tools, ultimately improving risk assessment and fire prevention strate-

gies. Furthermore, the findings may support the development of more

reliable wildfire prediction systems, which facilitate informed decision

making in fire management and emergency response.

Given the increasing frequency and intensity of wildfires worldwide,

particularly in regions at the wildland-urban interface (WUI), improv-

ing our understanding of ember transport is imperative. A more precise

characterization of ember dynamics can aid in the formulation of tar-

geted fire mitigation policies, including infrastructure protection mea-

sures and controlled burn strategies. Ultimately, the insights gained

from this research will contribute to reducing the destructive impact of

wildfires on buildings and communities in fire-prone regions.

Presenting Author: Luca Caracoglia Northeastern University

Presenting Author Biography: Professor, Civil and Environmental Engineering

Authors:

Gabriele Giuseppe Galeazzo Northeastern University
Luca Caracoglia Northeastern University
Khaled Ghannam Northeastern University