Abstract
A number of transonic airfoils, designed using differing approaches, are evaluated over a wide range of operating conditions, using a tool for generating aerodynamic performance maps. Details of key performance boundaries are also extracted, including drag divergence and separation onset. The aerodynamic performance maps and boundaries, which are based upon extensive use of a rapid 2D CFD tool, are first demonstrated on an existing airfoil, for which the design condition is known and for which experimental data is available. Aerodynamic maps are then presented for a series of airfoils which are designed using a sonic plateau, inverse design approach. Further maps are presented for airfoils designed using single-point and multi-point optimization. The impact of the alternative design approaches is studied, using the performance maps and the resulting characteristics of the performance boundaries. In particular, the trade-off between drag divergence and the onset of separation, combined with viscous and wave drag development, is presented. The study provides some insights into the challenge of achieving a well posed optimization formulation for transonic airfoil design.