Constrained Aerodynamic Optimization of the Flying-V Nose Cone and Center-Body Fairing

The unconventional Flying-V aircraft design was developed as an effort to meet the ever-growing demands of the aviation industry, aiming to overcome the plateau in annual fuel consumption reduction. Promising results have already been seen in structural weight, aerodynamic efficiency, high angle-ofattack handling qualities, and noise reduction ascribed to the over-wing installation of the engines. A nose cone model with interior components was established in a previous effort, together with a center-body trailing edge fairing to reduce the center-body pressure drag seen in the early aerodynamic studies. However, the models proved inadequate in generating designs reliably, hence the need for a redesign. The objective of the study at hand is to establish new parametric models that describe the shapes, perform a drag minimization study at cruise conditions that employs the Reynolds-Averaged Navier-Stokes equations and establish a method that enables such a procedure for graduate projects. In the numerical nose cone optimization, the design space is bound by radar and nose landing gear storage, pilot seating, and windshield size. In addition, the fairing shape is constrained by the size of the galley that it accommodates. The parametric models are built on the Knowledge Based Engineering platform ParaPy. A total of 24 design parameters are used to design the nose cone shape, and 20 are used for the fairing shape. The parametric models are established in such a way that they can easily be extended with more design variables to increase the complexity of the shapes. The existing Salome-ParaPy interface was extended with the ability to build hybrid meshes that incorporate tetrahedral and prism cells. This allows for spatial discretization suitable for resolving the boundary layer. During the aerodynamic shape optimization, meshes with 5 million cells are used. The optimizer, which employs six processes simultaneously, is coupled with the High Performance Computing 12 cluster at TU Delft to ensure a decrease in computational time for the aerodynamic simulations. In a parallel structure, the computationally costly nose cone constraints are assessed simultaneously with evaluating the forces on the cluster. The fairing constraints are analyzed before calculating the aerodynamic force coefficients. The aerodynamic shape design is performed at a constant angle-of-attack of 3°, a cruise Mach number of 0.85, and an altitude of 13.000 m. Adding the unoptimized nose cone and fairing shapes increases the drag coefficient by 1.3%. After both optimizations, the drag is reduced by 3.4% compared to the unoptimized design and by 2.1% with respect to the baseline Flying-V. Despite the fact that the shock severity on the center-body is not decreased markedly, the pressure drag sees a significant decrease. Notwithstanding the large curvature of the optimized nose cone, separation is only found on the trailing edge of the optimized shape. The windshield area increases by roughly 50% relative to the windshield of the A350 and the A320.Flying-VAerospace Engineerin