Transcript:

A Quieter BladeAmbience: wind turbineWind turbines are great way to harvest the power of one of nature's renewable forces. But they can be noisy. Engineers are trying to design a quieter turbine blade inspired by the structure of an owl's wing. I'm Jim Metzner and this is the Pulse of the Planet.Devenport: What we tried to do was to come up with shapes that we could put on a wing or on a wind turbine blade that would create the important features of the owls hair on on the back of the blade, but in a way that was practical and maybe could be an optimized for a wind turbine blade rather than an owl.Engineer William Devenport.Devenport: We had two basic ideas initially. One was called "finlets" - these were little fins that would stick up from the surface of the blade towards the back. And we envisioned that the top surface of these finlets, the little edges that were sticking up, would kind of behave like the owls hair perhaps was behaving.A second configuration we called rails, and rails looked a lot more like rigid hairs that come out gradually from the surface and together form a field just off the surface of the blade.We not only came up with his two basic ideas but we came up with variations, and we guessed over 20 different configurations. And then we ran the wind tunnel tests. We only had an opportunity to begin with, to run the test one time. And to our amazement, almost all of them worked. Almost all of them made the blade quieter, and at some frequency a lot quieter,as much as 10 dB quieter, which in terms of the energy - the sound energy made by the blade, means 10 times quieter.Pulse of the Planet is made possible in part by Virginia Tech, inventing the future through a hands on approach to education and research.