"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 researchers' results are providing details about how a fuzzy compliant but rough surface can be designed to tailor its acoustic signature.
A photographic study of actual owl feathers, carried out with Ian Clark of Virginia Tech, has revealed a surprising 'forest-like' geometry of the down material, so this will be incorporated into the researchers' future theoretical and experimental work to more faithfully replicate the down structure. Preliminary experiments performed at Virginia Tech show that a simple mesh covering, which replicates the top layer of the 'forest' structure, is effective in eliminating some sound generated by rough surfaces.
"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.
The presentation "Vortex Noise Reductions from a Flexible Fiber Model of Owl Down," is at 8:39 a.m. on Sunday, November 24, 2013 in the David L. Lawrence Convention Center, Room 319. ABSTRACT: http://meeting.aps.org/Meeting/DFD13/Event/202030
|Contact: Jason Socrates Bardi|
American Physical Society