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International Journal of Wildland Fire International Journal of Wildland Fire Society
Journal of the International Association of Wildland Fire
RESEARCH ARTICLE

Air tanker drop patterns

Dominique Legendre A C , Ryan Becker B , Elise Alméras A and Amélie Chassagne A
+ Author Affiliations
- Author Affiliations

A Institut de Mécanique des Fluides – UMR CNRS 5502, Allées du Professeur Camille Soula, F-31400 Toulouse, France.

B San Dimas Technology and Development Center (SDTDC) 444 East Bonita Avenue, San Dimas, CA 91773-3198, USA.

C Corresponding author. Email: dominique.legendre@imft.fr

International Journal of Wildland Fire 23(2) 272-280 https://doi.org/10.1071/WF13029
Submitted: 21 February 2013  Accepted: 24 July 2013   Published: 20 December 2013

Abstract

Ground patterns of liquid aerial drops for combating wildfires are considered. Based on a significant number of drop tests performed using different airplanes and helicopters, a simple model for the length, the width and the coverage distribution is presented. At first order both the length and the width of the drop pattern can be described using simple relations despite the significant difference between the conditions of the drop tests considered. These relations include factors that can be manipulated during aircraft and release system design, as well as during aerial firefighting operations. The liquid on the ground follows a Gaussian distribution that makes possible an original prediction of the maximum coverage level on the pattern centreline confirmed by the experiments. The difference between gravity systems and recent pressurised systems is also discussed. We show a clear difference between gravity systems and pressurised systems. The width is larger for pressurised systems, resulting in a smaller coverage for the same condition of drop.

Additional keywords: modelling.


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