The effect of rotor design on the fluid dynamics of helicopter brownout

Brown, R.E., Phillips, C. and Won, K.H. (2009) The effect of rotor design on the fluid dynamics of helicopter brownout. In: 35th European Rotorcraft Forum 2009, ERF 2009. Deutsche Gesellschaft fuer Luft und Raumfahrt (DGLR): Bonn, pp. 168-187. ISBN 9781615678747

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Abstract Helicopters operating close to the ground in dusty environments tend to generate large clouds of dust in the surrounding air. These clouds can obscure the pilot's view of the ground and lead to a dangerous condition known as brownout. Given the intimate relationship between the induced flow field around the rotor and the process through which the particulate matter becomes airborne and is subsequently transported, it has been speculated that the design of its rotor may influence the shape and size of the dust clouds that, are produced by any particular type of helicopter. This paper presents a study of the influence of two key geometric properties of the rotor on the development of these dust clouds. A particle transport model is coupled to Brown's Vorticity Transport Model to represent the dynamics of the particulate-air system surrounding a generic helicopter rotor under various flight conditions. The number of blades on the rotor is altered, whilst keeping the solidity constant, thus altering the distribution of vorticity that is released onto the ground. In addition, the twist of the blades is varied in order to investigate the effect of the resultant changes in the distribution of induced downwash on the evolution of the dust cloud. The study suggests that, in general, the larger the number of blades, and the higher the blade twist, the less dense the dust clouds that are produced under brownout conditions. It appears thus that the characteristics of the dust clouds are indeed sensitive to the geometry of the rotor and hence that careful aerodynamic design may allow the severity of brownout to be ameliorated

Item Type:Book Sections
Additional Information:35th European Rotorcraft Forum 2009, ERF 2009, September 22, 2009 - September 25, 2009, Hamburg, Germany
Glasgow Author(s) Enlighten ID:Brown, Dr Richard
Authors: Brown, R.E., Phillips, C., and Won, K.H.
College/School:College of Science and Engineering > School of Engineering > Aerospace Sciences
Publisher:Deutsche Gesellschaft fuer Luft und Raumfahrt (DGLR)

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