Owl wing design reduces plane, wind turbine noise air pollution

Trailing-edge noise is the dominant supply of sound from aeronautical and turbine engines like these in airplanes, drones, and wind generators. Suppressing this noise air pollution is a significant environmental aim for some city areas.

In Physics of Fluids, researchers from Xi’an Jiaotong University used the traits of owl wings to tell airfoil design and considerably cut back 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,” stated creator 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 alongside the again of an airfoil. The move varieties a turbulent layer of air alongside the higher and decrease surfaces of the airfoil, and when that layer of air flows again by means of the trailing edge, it scatters and radiates noise.

Previous research explored serrated trailing edges, discovering that the serrations successfully cut back the noise of rotating equipment. However, the noise reduction was not common, relying closely on the ultimate utility.

“At present, the blade design of rotating turbomachinery has gradually matured, but the noise reduction technology is still at a bottleneck,” stated Liu. “The noise reduction capabilities of conventional sawtooth structures are limited, and some new nonsmooth trailing-edge structures need to be proposed and developed to further tap the potential of bionic noise reduction.”

The workforce used noise calculation and evaluation software program to conduct a collection of detailed theoretical research of simplified airfoils with traits harking back to owl wings. They utilized their findings to suppress the noise of rotating equipment.

Improving the move situations across the trailing edge and optimizing the form of the sting suppressed the noise. Interestingly, uneven serrations decreased the noise greater than their symmetric counterparts.

Noise discount different with completely different working situations, so the scientists emphasised that the airfoil designs ought to be additional evaluated based mostly on the precise utility.

For instance, wind turbines have advanced incoming flow environments, which require a extra basic noise discount know-how. Examining noise discount methods beneath the affect of various incoming flows would make their conclusions extra common.

The researchers consider their work will function an essential information for airfoil design and noise management.