Owls
How scientists are studying the flight of barn owls to learn how to make wings and rotors more quiet.
How scientists are studying the flight of barn owls to learn how to make wings and rotors more quiet.
Source: https://www.smithsonianmag.com/science-nature/silence-wind-turbines-engineers-are-studying-owl-wings-180974659/
Laboratory measurements have shown that the slight swoosh made by a barn owl is below the threshold of human hearing until the owl is about three feet away — a feat of stealth that biologists and engineers are far from completely understanding.
First, Graham pointed out an unusual structure called the “comb,” which literally looks like a comb projecting forward from the wing’s leading edge. Second, he noted that most of the owl wing is covered with a soft layer of velvety feathers. Finally, he observed that the feathers on the trailing edge of the wing form a ragged fringe.
For an airplane coming in for a landing, a large part of the noise comes not from the engines but from the flow of air around the plane, especially the sound produced at the trailing edge of the wings. The turbulent air rushing past the exposed edges of the wings translates to the dull roar you hear as the plane flies overhead.
Laboratory measurements have shown that the slight swoosh made by a barn owl is below the threshold of human hearing until the owl is about three feet away — a feat of stealth that biologists and engineers are far from completely understanding.
First, Graham pointed out an unusual structure called the “comb,” which literally looks like a comb projecting forward from the wing’s leading edge. Second, he noted that most of the owl wing is covered with a soft layer of velvety feathers. Finally, he observed that the feathers on the trailing edge of the wing form a ragged fringe.
For an airplane coming in for a landing, a large part of the noise comes not from the engines but from the flow of air around the plane, especially the sound produced at the trailing edge of the wings. The turbulent air rushing past the exposed edges of the wings translates to the dull roar you hear as the plane flies overhead.