Supercritical wing design based on airfoil optimization and 2.75D transformation

An optimization design method for a supercritical wing is developed in this paper based on a pressure distribution transformation between the airfoil and wing. This transformation takes the stream-wise variation of the local sweep angle and the local curvature of a tapered swept wing into account. With this method, the desired pressure distribution of the wing, which is critical to its supercritical characteristics, as well as the constraints and objectives, can be mapped onto a 2D airfoil. When the airfoil is optimized, the desired performances and the pressure distributions can be well realized on a 3D wing. Test cases based on the RAE2822 airfoil and on the common research model are used to validate the CFD tool and the transformation. A supercritical wing is then designed using this method. Comparisons between the results from the proposed method, an optimization based on the traditional transformation and a fully 3D wing optimization are conducted. These comparisons show that the proposed method, by essentially performing 2D optimization, greatly improves the design efficiency. Moreover, the more accurate transformation helps make the optimization more reliable and engineering applicable.