Owls, apparently, are one of the most silent avian predators because of three wing characteristics that distinguish them from other birds. A team of researchers from Lehigh University's Department of Mechanical Engineering and Mechanics believe the principles of owl wings have real world applications. They are presenting their findings at the three-day, American Physical Society's (APS) Division of Fluid Dynamics meeting, which began on Sunday and ends on Tuesday, Science Recorder reported.
Justin Jaworski, one of the researchers, described the three regions that make owls stealthy as "a comb of stiff feathers along the leading edge of the wing, a flexible fringe at the trailing edge of the wing, and a soft, downy material distributed on the top of the wing," according to the press release.
Typically, the "flexible fringe at the trailing edge of the wing" (positioned at the bottom of the wing closest to the bird's body), acts as a bird's most prevalent "acoustic signature" and thus creates the most noise. In owls, however, this section of their wings -- also described as "compliant and porous" -- most dramatically reduces noise, according to previous research carried out by Jaworski. His current work, with the help of fellow Lehigh University professors and engineers, continues to study the flexibility fringe while attempting to determine how the other two target regions of owl wings contribute to sound reduction.
In particular, researchers wanted to better understand the "soft, downy material distributed on the top of the wing" (just below the flexible fringe). Like the flexible fringe, its most important acoustic characteristic is its texture.
"Our current work predicts the sound resulting from air passing over the downy material, which is idealized as a collection of individual flexible fibers, and how the aerodynamic noise level varies with fiber composition," Jaworski said.
The Lehigh team believes it can decrease noise emissions by manipulating the texture of surfaces ranging from the wings of airplanes to wind turbines to submarines, according to the release.
"If the noise-reduction mechanism of the owl down can be established, there may be far-reaching implications to the design of novel sound-absorbing liners, the use of flexible roughness to affect trailing-edge noise and vibrations for aircraft and wind turbines, and the mitigation of underwater noise from naval vessels," said Jaworski.
