WITHDRAWN: Curvature-Constrained Transonic Wing Adjoint-Based Aerodynamic Shape Optimization

The development of transonic wings involves challenges due to the complex physical phenomena that arise in this flow regime, such as shock waves, which make the flow nonlinear. During the preliminary design phase, the use of Reynolds-averaged Navier–Stokes (RANS) Computational Fluid Dynamics (CFD) simulations is crucial since it provides access to flow physics that are not present when using lower-fidelity tools. This allows for a more detailed exploration of the design space, facilitating the design of more aerodynamically efficient configurations. The adjoint method is significant in aerodynamic shape optimization (ASO) of transonic wings as it efficiently provides the necessary derivatives with high accuracy and low computational cost. Previous studies indicate that, when using the free-form deformation (FFD) parametrization strategy in ASO, increasing numbers of control points lead to more noticeable drag reductions, but the resulting optimum wings may present wavier surfaces. In this paper, we investigate the impact of including curvature constraints in the optimization of transonic wings to achieve smoother optimized configurations. Our results indicate that the inclusion of curvature constraints results in a smoother wing surface, for a given FFD discretization. The drag penalty that arises from employing the curvature constraints is close to 1%.