The new owl wing design reduces noise from aircraft and wind turbines
Turbine trailing edge noise is the dominant source of sound from aircraft and turbine engines, such as those in airplanes, drones, and wind turbines. Suppression of this noise pollution is a major environmental research goal. Researchers from Xi'an Jiaotong University took inspiration from owl wings to create a new turbine blade profile design to significantly reduce noise.
Night owls produce about 18 decibels less noise than other birds at similar flight speeds due to their unique wing structure. Trailing edge noise is generated as the airflow passes along the rear of the airfoil. The flow creates a turbulent layer of air along the upper and lower surfaces of the airfoil, and when this layer of air flows back over the trailing edge, sound is created.
Studies have examined serrated trailing edges of wings and found that serrations effectively reduce night owl wing noise.
The current turbine blade design creates a lot of noise during operation, research aimed to change that. They were inspired by the wings of a night owl. The team of scientists used software to calculate and analyze the noise. He carried out a series of detailed theoretical studies of simplified airfoils for aircraft wings and wind turbines with owl-like characteristics. They applied their knowledge to suppress the noise produced by these rotating machines.
Improving the flow conditions around the trailing edge and optimizing the edge shape suppressed the noise. Noise reduction varied under different operating conditions, so the researchers emphasized that airfoil designs should be further tested and improved.
For example, wind turbines are subject to frequent changes in airflow. Therefore, they require flexible noise reduction technology. Researching noise reduction techniques under the influence of different air flows will eventually lead to a universal design that will reduce noise in cities.
Scientists continue their research. From the results, they promise a big reduction in noise from airplanes or wind turbines.
Source: Lei Wang, Xiaomin Liu. Aeroacoustic investigation of asymmetric oblique trailing-edge serrations illuminated by owl wings. Physics of Fluids, 2022; 34 (1): 015113 DOI: 10.1063/5.0076272