Abstract

THIART, G.D.. Numerical lifting line method for high speed free surface effect and/or ground effect. R&D j. (Matieland, Online) [online]. 1999, vol.15, pp.16-25. ISSN 2309-8988.

A numerical lifting line method for the calculation of lift and induced drag on a straight wing of finite span in the proximity of a free surface, a ground surface, or a combination thereof is presented. The circulation distribution is expressed in terms of a Fourier sine series as for the classical Prandtl-Lanchester lifting line method. No approximations are introduced to linearize the lifting line equations, and the resulting nonlinear set of equations are solved iteratively. Results from the numerical lifting line method and approximate linearized methods available in the literature are compared for two practical wing planforms. Agreement between the two methods is shown to be good as long as the depth of submergence and/or ground clearance is large enough for the approximate method to be applicable.

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