Navigation Links
The secrets of owls' near noiseless wings
Date:11/24/2013

WASHINGTON D.C. Nov. 24, 2013 -- Many owl species have developed specialized plumage to effectively eliminate the aerodynamic noise from their wings allowing them to hunt and capture their prey in silence.

A research group working to solve the mystery of exactly how owls achieve this acoustic stealth will present their findings at the American Physical Society's (APS) Division of Fluid Dynamics meeting, held Nov. 24 26, in Pittsburgh, Pa. -- work that may one day help bring "silent owl technology" to the design of aircraft, wind turbines, and submarines.

"Owls possess no fewer than three distinct physical attributes that are thought to contribute to their silent flight capability: a comb of stiff feathers along the leading edge of the wing; a flexible fringe a the trailing edge of the wing; and a soft, downy material distributed on the top of the wing," explained Justin Jaworski, assistant professor in Lehigh University's Department of Mechanical Engineering and Mechanics. His group is exploring whether owl stealth is based upon a single attribute or the interaction of a combination of attributes.

For conventional wings, the sound from the hard trailing edge typically dominates the acoustic signature. But prior theoretical work carried out by Jaworski and Nigel Peake at the University of Cambridge revealed that the porous, compliant character of the owl wing's trailing edge results in significant aerodynamic noise reductions.

"We also predicted that the dominant edge-noise source could be effectively eliminated with properly tuned porous or elastic edge properties, which implies that that the noise signature from the wing can then be dictated by otherwise minor noise mechanisms such as the 'roughness' of the wing surface," said Jaworski.

The velvety down atop an owl's wing creates a compliant but rough surface, much like a soft carpet. This down material may be the least studied of the unique owl noise attributes, but Jaworski believes it may eliminate sound at the source through a novel mechanism that is much different than those of ordinary sound absorbers.

"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
dfdmedia@aps.org
240-535-4954
American Physical Society
Source:Eurekalert  

Related biology news :

1. Structure of bacterial nanowire protein hints at secrets of conduction
2. The secrets of a bugs flight
3. EARTH Magazine: CSI La Brea -- Tiny traces reveal big secrets of the tar pits
4. Singapore scientists expose molecular secrets of bile duct cancers from different countries
5. Tuberculosis genomes portray secrets of pathogens success
6. Scientists uncover secrets of starfishs bizarre feeding mechanism
7. Geoscientists unearth mineral-making secrets potentially useful for new technologies
8. Genetic secrets of the worlds toughest little bird
9. Biomedical research revealing secrets of cell behavior
10. Virtual skin model reveals secrets of skin aging
11. DNA sequencing uncovers secrets of white cliffs of Dover
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
The secrets of owls' near noiseless wings
(Date:3/24/2017)... Research and Markets has announced the addition of the ... Industry Forecast to 2025" report to their offering. ... The Global Biometric Vehicle Access ... 15.1% over the next decade to reach approximately $1,580 million by ... and forecasts for all the given segments on global as well ...
(Date:3/23/2017)... Research and Markets has announced the addition of the "Global ... 2025" report to their offering. ... The Global Vehicle Anti-Theft System Market is ... next decade to reach approximately $14.21 billion by 2025. ... all the given segments on global as well as regional levels ...
(Date:3/22/2017)... NEW YORK , March 21, 2017 /PRNewswire/ ... Customer Marketing Cloud used by retailers such as ... in its platform — Product Recommendations and Replenishment. Using ... to give more personalized product and replenishment recommendations ... purchases, but also on predictions of customer intent ...
Breaking Biology News(10 mins):
(Date:6/22/2017)... ... June 22, 2017 , ... For the months ... produced a Spotlight series on “Cell Therapy Regulation” for its regenerative ... experts on the unique regulatory challenges of stem cell medical research. , Stem ...
(Date:6/22/2017)... ... June 22, 2017 , ... RURO, Inc., ... Limfinity® version 6.5, a content-packed update to the Limfinity® framework. , LimitLIS® and ... and more diverse base of customers among labs and other businesses. Limfinity® 6.5 ...
(Date:6/20/2017)... ... ... Biologist Dawn Maslar MS has found a biomarker that she claims verifies ... The Neuroscience of Meeting, Dating, Losing Your Mind, and Finding True Love, Maslar found ... step, in my estimation, was to scientifically track the evidence of commitment in men,” ...
(Date:6/20/2017)... ... June 20, 2017 , ... ... PhD, a well-versed leader with extensive assay development and biomarker expertise, as VP ... is a Boston CRO specializing in bio-analytical assay development and sample testing services. ...
Breaking Biology Technology: