2007.140: Nonlocal flow effects in bushfire spread rates
2007.140: J.W. Dold, A. Zinoviev and R.O. Weber (2006) Nonlocal flow effects in bushfire spread rates. In: Proceedings of 5th International Conference on Forest Fire Research, 2006.
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The entrainment of air into the bouyant flame and plume above any part of a fireline must affect the air flow at all other parts of the fireline. Thus the local wind actually felt at any one part of the fire is not necessarily the ambient wind; it is influenced, nonlocally, by all other parts of the fireline. By modelling this effect of bouyancy on the ambient air as a line of suction above the fireline, with a height and strength that varies with intensity of burning along the fireline, the changes in air flow can be calculated for any given shape and size of fireline. To illustrate the nature of the model, a fixed elliptical shape of fireline is examined within a steady ambient wind, as measured far from the fire. A reduction in head fire spread rate is predicted for finite widths of the fireline and, if the scale of the fireline increases, the spread rate approaches the limiting value of the potential spread rate. The model is therefore in qualitative agreement with the basic experimental findings of Cheney and Gould (1995).
|Item Type:||Conference or Workshop Item (Paper)|
|Uncontrolled Keywords:||fire spread rate, modelling, air flow, entrainment|
|Subjects:||MSC 2000 > 00 General|
|Deposited By:||Mrs Louise Healey|
|Deposited On:||14 November 2007|