LES analysis on the effects of fire source asymmetry on enhanced wind by fire

• Published in: International Journal of Thermofluids 2023-05, Vol.18, p.100317, Article 100317
• Main Authors: Eftekharian, Esmaeel, Rashidi, Maria, Salehi, Fatemeh, Samali, Bijan
• Format: Article
• Language: English
• Subjects: Counter-rotating vortices; Fire source asymmetry; Fire-wind interaction; Wind enhancement
• ISSN: 2666-2027; 2666-2027
• DOI: 10.1016/j.ijft.2023.100317

•Wind enhancement behaviour by an asymmetrical fire source was studied.•The effects of fire source asymmetry on counter-rotating vortices were investigated.•Deviation from fire source symmetry disturbs the counter-rotating vortex symmetry.•An asymmetrical fire source triggers an imbalance in the wind enhancement. Investigation of aerodynamic characteristics of wind enhanced by bushfires is of great significance due to their destructive impacts on buildings located in bushfire-prone areas. Despite the abundance of studies in the fire-wind interaction domain, there have been limited studies concerning the effects of fire on wind aerodynamics. Fire source shape is one of the main factors affecting enhanced wind by fire. This study reports on the effects of fire source asymmetry on aerodynamic changes of wind by fire using a large eddy simulation analysis based on fireFoam solver of OpenFOAM platform. Wind aerodynamic analysis was performed by implementing a module to the solver to extract the corresponding components of fire-induced pressure gradient and acceleration. The results revealed that deviation from fire source symmetry results in asymmetric behaviour of counter-rotating vortices where the maximum cross-sectional wind enhancement occurs. Moreover, the concept of the first-moment area was used to quantify the level of fire source deviation from symmetry and it was shown that the higher first-moment area (about the equivalent symmetry axis) corresponds to a higher deviation from symmetry which delays the realignment of counter-rotating vortices toward the horizontal vortex line.