Multidisciplinary Design Optimization of Aircraft Wings with Active Flow Control

The next generation of aircraft needs to find solutions in order to face environmental, economic, and social challenges. This implies the use and improvement of advanced technologies. To achieve significant improvements in energy efficiency, merely optimizing existing technologies may not suffice. Consequently, more revolutionary advancements in airframe and propulsion technologies are essential to meet the stipulated recommendations for future aircraft. Furthermore, implementing these advanced technologies will require the development of innovative aircraft designs that can fully harness their potential, thereby maximizing overall energy efficiency. The current thesis concentrates on developing and enhancing tools characterized by a medium-fidelity level of accuracy to assess the effect of advanced technologies such as boundary layer suction, load alleviation, advanced material, and unconventional aircraft designs. In particular, the forward-swept configuration and those featuring electric propulsion are explored, in addition to the common backward-swept wing with fuel propulsion. A focus is given to boundary layer suction. This allows to take into account the transition to turbulent flow due to different instabilities, such as Tollmien–Schlichting, crossflow, and attachment line. In particular, these tools are coupled in a framework characterized by different blocks and designed for aerostructural optimization to establish aircraft performance. The framework can be applied to the analysis and sizing of aircraft from different classes, from regional to medium-range applications. A long-range study is possible for a limited Mach number. Therefore, aerostructural analysis in the presence of active flow control may be performed from the subsonic to the transonic regime. A special framework can be implemented to consider the wing aeroelastic deformation, but it presents some limitations related to the hybrid laminar flow control treatment. Different test cases are shown to prove the tools’ capabilities and, as a consequence, the optimization framework. These are the short and medium-range aircraft designed inside the Cluster of Excellence Sustainable and Energy Efficient Aviation (SE2A). Besides, the work shows some strategies to refine the low-fidelity analysis for active flow control at the early design stage. The studied test cases not only show the potential benefits of the technology and how to assess them numerically, but also how sensitive the parameters, such as the design variables or the level of technologies used, influence final performance. Finally, a multi-fidelity strategy involving the complete flight envelope is implemented to connect the accuracy given by medium-fidelity tools and the low-fidelity ones for preliminary design and mission analysis, together with some high-fidelity aerodynamic analysis for low-speed segments. The investigation shows the fundamental role of the medium fidelity approach, especially in being accurate enough to evaluate range performance, costs, and emissions in the presence of complex phenomena characterized by the mentioned advanced technologies.