Owl wing design reduces aircraft, wind turbine noise pollution

Owl wing design reduces aircraft, wind turbine noise pollution

The shape of owl wings, which help the animals fly quietly, can inform flyer leaf design. Credit: Wang and Liu

Rear edge noise is the predominant source of noise from aviation and turbine engines such as those in aircraft, drones and wind turbines. Suppressing this noise pollution is an important environmental goal for some urban areas.

IN Physics of liquids, researchers from Xi’an Jiaotong University used the properties of owl wings to inform flyer design and significantly reduce trailing edge noise.

“Night owls produce about 18 decibels less noise than other birds at similar flight speeds due to their unique wing configuration,” said author Xiaomin Liu. “Moreover, when the owl catches prey, the shape of the wings also changes constantly, so the study of the wingtip configuration during owl flying is of great importance.”

Rear edge noise is generated when the air flow passes along the back of a support surface. The current forms a turbulent air layer along the upper and lower surface of the bearing surface, and when that air layer flows back through the trailing edge, it diffuses and emits noise.

Previous studies examined serrated trailing edges and found that the serrations effectively reduce the noise from rotating machinery. However, the noise reduction was not universal, depending on the end use.

“At present, the wing design of rotary turbomachines has gradually matured, but the noise reduction technology is still in a bottleneck,” Liu said. “The noise reduction capabilities of conventional sawtooth structures are limited, and some new non-slip trailing edge structures need to be proposed and developed to further exploit the potential for bionic noise reduction.”

The team used noise calculation and analysis software to perform a series of detailed theoretical studies of simplified bearing surfaces with properties reminiscent of owl wings. They used their results to suppress the noise from rotating machines.

Improving the flow conditions around the trailing edge and optimizing the shape of the edge suppressed the noise. Interestingly, reduced asymmetric thanks to the noise more than their symmetrical counterparts.

The noise reduction varied with different operating conditions, so the researchers emphasized that the bearing profile designers had to be further evaluated based on the specific application.

For example, wind turbines have complex incoming flow environments that require more general noise reduction technology. Study of noise reduction techniques under the influence of different input currents would make their conclusions more universal.

The researchers believe their work will serve as an important guide to flyer design and noise control.

Owl wings could hold the key to beating wind turbine noise

More information:
“Aeroacoustic study of asymmetric inclined saw teeth in the trailing edge illuminated by owl wings” Physics of liquids (2022). DOI: 10.1063 / 5.0076272

Provided by the American Institute of Physics

Citation: Owl wing design reduces aircraft, wind turbine noise pollution (2022, 18 January) retrieved 19 January 2022 from https://phys.org/news/2022-01-owl-wing-aircraft-turbine-noise.html

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