'Trailing-edge noise' is the dominant source of sound from aeronautical and turbine engines like those in aeroplanes, drones, and wind turbines.

Researchers from Xi’an Jiaotong University in China used the characteristics of owl wings to inform aerofoil designs that help to significantly reduce the trailing-edge noise.

“Nocturnal owls produce about 18 decibels less noise than other birds at similar flight speeds due to their unique wing configuration,” said study author Xiaomin Liu.

“Moreover, when the owl catches prey, the shape of the wings is also constantly changing, so the study of the wing edge configuration during owl flight is of great significance.”

Trailing-edge noise is generated when airflow passes along the back of an aerofoil. The flow forms a turbulent layer of air along the upper and lower surfaces of the aerofoil, and when that layer of air flows back through the trailing edge, it scatters and radiates noise.

Previous studies...