A study of the canopy effect on fire regime transition using an objectively defined Byram convective number

Autor: Salman Verma, Aymeric Lamorlette, Kai Zhang, Arnaud Trouvé
Přispěvatelé: Laboratoire de Tribologie et Dynamique des Systèmes (LTDS), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-École Nationale des Travaux Publics de l'État (ENTPE)-Ecole Nationale d'Ingénieurs de Saint Etienne-Centre National de la Recherche Scientifique (CNRS), Department of Fire Protection Engineering [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire de Mécanique, Modélisation et Procédés Propres (M2P2), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Université de Lyon-Université de Lyon-École Nationale des Travaux Publics de l'État (ENTPE)-Ecole Nationale d'Ingénieurs de Saint Etienne (ENISE)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Fire Safety Journal
Fire Safety Journal, Elsevier, 2020, 112, pp.102950. ⟨10.1016/j.firesaf.2020.102950⟩
Fire Safety Journal, 2020, 112, pp.102950. ⟨10.1016/j.firesaf.2020.102950⟩
ISSN: 0379-7112
1873-7226
DOI: 10.1016/j.firesaf.2020.102950⟩
Popis: Forest fires can be classified into two regimes, depending on Byram convective number NC: a plume-dominated and wind-driven regime. This classification is often based on two-dimensional (2D) studies without considering flame front structures, and is associated with the change of governing heat transfer mechanism. Studies based on three-dimensional (3D) considerations suggest the dependency of the fire regime transition on canopy characteristics C d L A I ( C d α s σ s H F / 2 ) through which the atmosphere boundary layer (ABL) flow changes to mixing layer (ML) flow. Hence, the primary objective of the present study is to investigate the fire regime transition and its associated heat transfer mechanisms with the aid of drawing a dimensionless configuration space {NC, CdLAI}. This requires an objective definition of the Byram convective number; the 2 m or 10 m high open wind speed ( U ∞ = U 2 or U 10 ) often used to define it being arbitrary. Therefore, the present study introduces a scaling method for the reference height ( Y r e f ) at which the wind speed U r e f is chosen to define a new Byram convective number NC’. A mathematical expression for Y r e f as a function of canopy/vegetation height is proposed for a small-scale, stationary fire. The new configuration space {NC’, CdLAI} is considered more suitable for investigating the fire regime transition.
Databáze: OpenAIRE
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