Windmills, fans and drones could perhaps be made quieter by examining hummingbird wing beat. Researchers from Eindhoven and the US have looked at exactly where the sound of the fast birds comes from.
The researchers from Eindhoven University of Technology, a company from Eindhoven and Stanford University used twelve high-speed cameras and 2,176 microphones to measure the wing sound of six hummingbirds when they drank nectar hanging in front of a fake flower.
The hummingbird makes a soft sound when flying. How exactly the wing does this has only now been established. The elastic, complex wings of a hummingbird make noise in the same way as the simpler wings of insects.
Hummingbirds are the ‘helicopters’ of the birds. They can hover still in the air, fly up and down and even backwards. They can flap their wings up to 40 times per second.
Humming, humming and humming
Unlike other bird species, the hummingbird wing generates a strong upward aerodynamic force during both the upward and downward wing beat.
“That’s why birds and insects make so many different sounds,” says Professor David Lentink of Stanford University. “Mosquitoes buzz, bees hum, hummingbirds hum and larger birds whoose. Most birds are relatively quiet because they only generate the most lift once, on the downward wing beat. Hummingbirds and insects are noisier, because they do it twice per wing beat. . “
The researchers say their goal was not to look at how windmills, drones and fans can become quieter, but the knowledge gained from the hummingbirds can now be used for this.
“If you know how the complex aerodynamic forces of an animal produce sound, you can use that knowledge to make flying or moving devices that generate complex forces quieter. Think of drones, computer fans and possibly even wind turbines,” says an Eindhoven researcher.
Windmills and fans may be quieter due to research on hummingbirds
Source link Windmills and fans may be quieter due to research on hummingbirds