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Shape optimization is a very time-consuming and expensive task, especially if experimental tests need to be performed. To overcome the challenges of geometry optimization, the industry is increasingly relying on numerical simulations. These kinds of problems typically involve the interaction of three main applications: a solid modeler, a multi-physics solver, and an optimizer. In this manuscript, we present a shape optimization work-flow entirely based on open-source tools; it is fault tolerant and software agnostic, allows for asynchronous simulations, and has a high degree of automation. To demonstrate the usability and flexibility of the proposed methodology, we tested it in a practical case related to the naval industry, where we aimed at optimizing the shape of a bulbous bow in order to minimize the hydrodynamic resistance. As design variables, we considered the protrusion and immersion of the bulbous bow, and we used surrogate-based optimization. From the results presented, a non-negligible resistance reduction is obtainable using the proposed work-flow and optimization strategy.

Winglets are commonly used drag-reduction and fuel-saving technologies in today’s aviation. The primary purpose of the winglets is to reduce the lift-induced drag, therefore improving fuel efficiency and aircraft performance. Traditional winglets are designed as fixed devices attached at the tips of the wings. However, because they are fixed surfaces, they give their best lift-induced drag reduction at a single design point. In this work, we propose the use of variable cant angle winglets which could potentially allow aircraft to get the best all-around performance (in terms of lift-induced drag reduction), at different angle-of-attack values. By using computational fluid dynamics, we study the influence of the winglet cant angle and sweep angle in the performance of a benchmark wing at a Mach number of 0.8395. The results obtained demonstrate that by carefully adjusting the cant angle, the aerodynamic performance can be improved at different angles of attack.

The preliminary design of a biologically inspired flapping UAV is presented. Starting from a set of initial design specifications, namely: weight, max- imum flapping frequency and minimum hand-launch velocity of the model, a parametric numerical study of the proposed avian model is conducted in terms of the aerodynamic performance and longitudinal static stability in gliding and flapping conditions. The model shape, size and flight conditions are chosen to approximate those of a gull. The wing kinematics is selected after conducting an extensive parametric study, starting from the simplest flapping pattern and progressively adding more degrees of freedom and control parameters until reaching a functional and realistic wing kinematics. The results give us an initial insight of the aerodynamic performance and longitu- dinal static stability of a biomimetic flapping UAV, designed at minimum flight velocity and maximum flapping frequency

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