Aerodynamic and Aeroelastic Shape Optimization of Aircraft Wings

The goal of this thesis is to develop an efficient framework for aerodynamicand aeroelastic shape optimization. The framework includes coupled aerodynamic and structural analysis, where a multidisciplinary formulation is used in order to create optimized trade-offs between structural and aerodynamic performance. A primary challenge with these problems is the computational expense of solving the coupled problem on each design iteration. In order to help overcome this expense, panel methods are used to calculate the aerodynamic loadswhich are an efficient alternative to conventional CFD methods. Beam finiteelement models are used in this thesis to capture structural deformations, butextensions to 3D continuum finite elements are also discussed. All optimization problems are solved using gradient-based methods, where gradients are derived analytically and implemented using a discrete adjoint approach. The methodology developed throughout this thesis has been applied to the designof aircraft wings. Results demonstrate the applicability of the methods, andthe framework is used to explore the potential of unconventional aircraft wingdesigns such as curved wall spars and drooped wings.The specific details of the thesis are covered by four journal publications which contain the following topics:

P1. The aerodynamic optimization framework is introduced which lays outthe main considerations for solving aerodynamic optimization problemswith panel methods, namely: choice of boundary conditions; drag calculationmethods; parameterization methods; regularization; and wakemodeling.

P2. The coupled panel-beam framework for aeroelastic optimization is introduced.The publication includes a general panel-beam load-displacementtransfer scheme, parameterizations that define both the external winggeometry and internal structural geometry, and investigations conductedon the benefits of curved wall spars in wingbox design.

P3. A parameterization is presented for aerodynamic optimization of nonplanarwings. The method is able to improve upon reference designstaken from the literature, and is used to investigate the potential performancebenefits of drooped wings compared to more traditional raisedwing designs with winglets.

P4. The coupled aeroelastic framework is extended to include a non-linearco-rotating beam model. The results demonstrate the importance of capturingnon-linear deformations in aeroelastic optimization problems, andpresents aeroelastic comparisons of solid foam core wings with raised anddrooped geometry.