adm


The Aerial Drop Model, ADM, is intended for the near real-time simulation of the aerial drop of firefighting liquids from fixed-wing aircraft, while covering the fundamental stages of the process. It copes with a wide range of product viscosities, from water to highly thickened long-term retardants. ADM simulates the continuous stripping of droplets from the liquid jet by the action of Rayleigh-Taylor and Kelvin-Helmholtz instabilities through the linear stability theory. The subsequent secondary breakup and deformation of the formed droplets due to aerodynamic forces is based on experimental correlations defined in terms of the dimensionless Weber number. Droplets’ trajectories are computed by applying a lagrangian approach, in which a dynamical drag module accounts for the effect of deformation.

 

It has been validated by the statistical comparison against a set of real scale drop tests conducted with a conventional and a constant flow delivery systems. From the investigation of model performance, good accuracy was obtained for the wide range of input conditions tested.

 

This operational tool provides an improved understanding of the behaviour and effectiveness of aerially-delivered firefighting liquids. Due to its characteristics and capabilities, this operational tool can potentially be used in formation, training and demonstration activities with pilots, aerial resource coordinators, civil protection personnel and ground firefighters, or in testing the effectiveness of new firefighting chemicals and discharge systems, complementing the data obtained from real scale drop tests and laboratorial experiments. ADM could also significantly reduce the cost of evaluating the benefits of airtanker drop controller modifications and changes to tactical retardant application by eliminating the need to perform exhaustive drop testing after incorporating changes.


References

 

AMORIM J.H. (2011) Numerical modelling of the aerial drop of firefighting agents by fixed-wing aircraft – Part I: Model development. International Journal of Wildland Fire (IJWF). 20, 384–393.

 

AMORIM J.H. (2011) Numerical modelling of the aerial drop of firefighting agents by fixed-wing aircraft – Part II: Model validation. International Journal of Wildland Fire (IJWF). 20, 3, 394–406.

AMORIM J.H., BORREGO C. and MIRANDA A.I. (2009) Development and validation of an operational numerical model for the simulation of the aerial drop of firefighting products. Eighth Symposium on Fire and Forest Meteorology. 13-15 October 2009, Kalispell, Montana, USA.

 

AMORIM J.H. (2008) Numerical modelling of the aerial drop of products for forest firefighting. PhD Thesis. Department of Environment and Planning, University of Aveiro, Portugal. 190 p.

última atualização a 15-04-2014
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