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Role of buoyant flame dynamics in wildfire spread

Author(s): Mark A. Finney, Jack D. Cohen, Jason M. Forthofer, Sara S. McAllister, Michael J. Gollner, Daniel J. Gorham, Kozo Saito, Nelson K. Akafuah, Brittany A. Adam, Justin D. English
Year Published: 2015

Large wildfires of increasing frequency and severity threaten local populations and natural resources and contribute carbon emissions into the earth-climate system. Although wildfires have been researched and modeled for decades, no verifiable physical theory of spread is available to form the basis for the precise predictions needed to manage fires more effectively and reduce their environmental, economic, ecological and climate impacts. Here, we report new experiments conducted at multiple scales which appear to reveal how wildfire spread derives from the tight coupling between flame dynamics induced by buoyancy and fine-particle response to convection. Convective cooling of the fine-sized fuel particles in wildland vegetation is observed to efficiently offset heating by thermal radiation until convective heating by contact with flames and hot gasses occurs. The structure and intermittency of flames that ignite fuel particles were found to correlate with instabilities induced by the strong buoyancy of the flame zone itself. Discovery that ignition in wildfires is critically dependent upon non-steady flame convection governed by buoyant and inertial interaction advances both theory and the physical basis for practical modeling.

Citation: Finney, Mark A.; Cohen, Jack D.; Forthofer, Jason M.; McAllister, Sara S.; Gollner, Michael J.; Gorham, Daniel J.; Saito, Kozo; Akafuah, Nelson K.; Adam, Brittany A.; English, Justin D. 2015. Role of buoyant flame dynamics in wildfire spread. PNAS. doi: 10.1073/pnas.1504498112.
Topic(s): Fire Behavior, Data Evaluation or Data Analysis for Fire Modeling
Ecosystem(s): None
Document Type: Book or Chapter or Journal Article
NRFSN number: 13377
Record updated: Jun 14, 2018