TWO-DIMENSIONAL AIRCRAFT HIGH LIFT SYSTEM DESIGN AND OPTIMIZATION

A two-dimensiona l aircraft high-lift system design and optimization method, which can be easily extended to three dimensions, is presented. The need for such a tool is assessed. The method uses a gradient based local optimizer. The aerodynamic performance is predicted using an Interactive Boundary Layer (IBL) approach. Methods to represent general multi-element airfoils by a set of design variables are described. The representation of airfoils by general shape functions as well as element positioning (deflection angle, gap, overlap) is considered. The accuracy of the IBL approach when Reynolds number, element gap, overlap and deflection are varied is investigated. The design/optimization approach is first validated for an inverse design by matching a pressure coefficient distribution. Next, the method is applied to multi-element airfoil lift to drag ratio and single airfoil maximum lift coefficient maximization. Results demonstrate the appropriateness of the approach for high lift system design and optimization.

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