Engine Noise – Fly Like a Bird

music
ambience: Great Horned Owl, Jet aircraft Engine

Owls and other predatory birds are famous for their nearly silent flying. Engineers have been observing the wing design of these birds, searching for ways to make commercial aircraft quieter. I’m Jim Metzner, and this is the Pulse of the Planet.

Dennis Huff is a researcher at Glenn Research center. He’s part of a team that developed the ‘chevron nozzle,’ a new technology that’s starting to be introduced in commercial planes it’s an idea that takes its cue from the design of bird wings.

“The chevron nozzle is one of the more recent success stories for jet noise reduction. If you add this chevron nozzle to the back of the engine, it simulates a what looks like a saw tooth pattern on the back of the nozzle, that essentially is mixing the stream in a favorable way such that the turbulence is being reduced and they reduce the jet noise by about 3 decibels. So that’s a fairly significant number. If you had two lawnmowers running and turned one off, it would reduce the noise by 3 decibels.”

Well, right now, we’re listening to the sound of a typical jet engine on a commercial aircraft. Well, here’s what the engine would sound like if it employed all of the currently available noise-reduction technology.

“The airplanes of the future I think will look very different, in that they’re going to look more and more, I hate to say it, but they are going to look more and more like a bird. The chevron nozzles might be an example of that, where you look at the back of a bird, you’ve got feathers that have a serrated texture to them and essentially that’s helping them mix the flow field together. So, I think there’s a lot we can learn from Mother Nature.”

In upcoming programs, we’ll hear more about what the quieter aircraft of the future might look and sound like. Pulse of the Planet is made possible by the National Science Foundation with additional support from NASA. I’m Jim Metzner.

music

Engine Noise - Fly Like a Bird

By looking to the skies (and the birds flying in them) engineers hope to develop quieter jet engines.
Air Date:08/22/2006
Scientist:
Transcript:

music
ambience: Great Horned Owl, Jet aircraft Engine

Owls and other predatory birds are famous for their nearly silent flying. Engineers have been observing the wing design of these birds, searching for ways to make commercial aircraft quieter. I'm Jim Metzner, and this is the Pulse of the Planet.

Dennis Huff is a researcher at Glenn Research center. He's part of a team that developed the 'chevron nozzle,' a new technology that's starting to be introduced in commercial planes it's an idea that takes its cue from the design of bird wings.

"The chevron nozzle is one of the more recent success stories for jet noise reduction. If you add this chevron nozzle to the back of the engine, it simulates a what looks like a saw tooth pattern on the back of the nozzle, that essentially is mixing the stream in a favorable way such that the turbulence is being reduced and they reduce the jet noise by about 3 decibels. So that's a fairly significant number. If you had two lawnmowers running and turned one off, it would reduce the noise by 3 decibels."

Well, right now, we're listening to the sound of a typical jet engine on a commercial aircraft. Well, here's what the engine would sound like if it employed all of the currently available noise-reduction technology.

"The airplanes of the future I think will look very different, in that they're going to look more and more, I hate to say it, but they are going to look more and more like a bird. The chevron nozzles might be an example of that, where you look at the back of a bird, you've got feathers that have a serrated texture to them and essentially that's helping them mix the flow field together. So, I think there's a lot we can learn from Mother Nature."

In upcoming programs, we'll hear more about what the quieter aircraft of the future might look and sound like. Pulse of the Planet is made possible by the National Science Foundation with additional support from NASA. I'm Jim Metzner.

music