Innovative wing surface coating to reduce drag
Approximately 25 % of EU carbon dioxide (CO2) emissions are produced by the aeronautics sector. Technologies that improve aerodynamics are important in combating this statistic because reducing drag decreases fuel consumption and combustion is the main generator of CO2. Nature is often the source of inspiration for scientists, and the aerodynamics of birds in flight provides a rich source of ideas for aerospace engineers. The EU-funded project PEL-SKIN (PEL-SKIN: A novel kind of surface coatings in aeronautics) investigated a novel aerofoil coating inspired by the pop-up of some birds in flight. Scientists developed an aerofoil coating (a porous and elastic (PEL) skin) consisting of a densely packed arrangement of flexible fibres able to reconfigure and adapt to flow separation around the wing. Researchers exploited a combination of theoretical, numerical and experimental investigations. Research work shed further insight into the interactions between fluid flows and the wing structure, and led to development of a new model for studying flow control through the poroelastic coating. This new concept of flow control can significantly increase aerodynamic efficiency and improve stability by delaying stall and reducing vibrations induced by gusts during take-off and landing, when the effects of the boundary layer separation are pronounced. Compared to fixed rigid devices, this PEL coating can flexibly move, deform and adapt to the surrounding flow field. It is activated only when the boundary layer is separated and interacts with the flow recirculation zone to reduce drag through interaction with the near-wall flow. During the cruise phase, the PEL coating remains inactive and flush with the wing surface, unlike the classical mounted devices that pose an obstacle to air flow. Project advancements in airflow manipulation could bring significant fuel savings. PEL-SKIN developments promise to significantly reduce drag, making an important contribution to both the competitiveness and sustainability of the aerospace sector.
Keywords
Surface coating, drag, aircraft wings, flow control, aeronautics, PEL-SKIN, aerofoil
