21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-2.9.3

AN IMPROVED METHOD FOR THE DESIGN AND CALCULATION OF AERODYNAMIC CHARACTERISTICS OF AIRFOILS WITH THE DOMINANT TURBULENT BOUNDARY LAYER AT SUBSONIC AND LOWER TRANSONIC SPEEDS

Kostic I.
University of Belgrade, F. R. of Yugoslavia

Keywords: design, aerodynamic, airfoils, turbulent boundary layer, subsonic, lower transonic

In this paper, the most important aspects of computation techniques applied in a computer program TRANPRO, used for the airfoil design, optimization and analysis are presented. Speed domain in applications ranges from small subsonic to lower transonic values, with the corresponding Reynolds numbers usual for the aviation purposes. This program is a higher and more sophisticated version of the well known program Trandes, whose upgraded modes for airfoil design and analysis are used in TRANPRO as subroutines. The new computer program has several important advantages, among which a specific inverse-direct approach in airfoil design is the most relevant. In the inverse phase of the design mode, trailing edge closure is achieved automatically, while in Trandes, the user was supposed to redefine Cp input by himself (in the direct phase which does not exist in Trandes); the airfoil shape is additionally adjusted to strictly satisfy required value of a chosen important aerodynamic parameter, if such a necessity exists. Turbulent boundary layer calculation applied in TANPRO overcomes the problems of the original Carlson / Nash / Macdonald model, which generally underestimates the profile drag values. Improvements were also made in the wave drag calculations.

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