Owl feather finlets on leading edge of reduced aircraft noise

A new study from City, University of London has found that small finlets on owl feathers could inspire wing designs that reduce aircraft noise.

Image by Chris Horvath, Pixabay

Led by Professor Christoph Bruecker, the team in London collaborated with RWTH Aachen University in Germany and used 3D geometry data of typical owl feather examples reconstructed by RWTH’s Professor Hermann Wagner. These reconstructions were carried out in earlier studies by Wagner and his team using high-resolution micro-CT scans.

Their research, published in Bioinspiration and Biomimetics , outlines the translation of the feather examples into a biomimetic aerofoil to study the aerodynamic effect on the filaments at the leading edge of the feathers. 

Results show that the structures work as arrays of finlets which coherently turn the flow direction near the aerodynamic wall, keeping the flow for longer and with greater stability, avoiding turbulence. It is hoped that the outcome of their research could prove important for future laminar wing design.

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This effect is known to stabilise the flow over a swept wing aerofoil, typical for owls while flapping their wings and gliding. Using flow studies in a water tunnel, Bruecker is said to have proved the flow turning hypothesis in experiments with an enlarged finlet model.

Instead of producing vortices, the finlets were found to act as thin guide vanes due to their 3D curvature. The team are now planning to use a technical realisation of such a swept wing aerofoil pattern in an anechoic wind tunnel for further acoustic tests.