Hummingbird feather sounds are produced by aeroelastic flutter, not vortex-induced vibration

Males in the 'bee' hummingbird clade produce distinctive, species-specific sounds with fluttering tail feathers during courtship displays. Flutter may be the result of vortex shedding or aeroelastic interactions. We investigated the underlying mechanics of flutter and sound production of a series of different feathers in a wind tunnel. All feathers tested were capable of fluttering at frequencies varying from 0.3 to 10 kHz. At low airspeeds (Uair) feather flutter was highly damped, but at a threshold airspeed (U*) the feathers abruptly entered a limit-cycle vibration and produced sound. Loudness increased with airspeed in most but not all feathers. Reduced frequency of flutter varied by an order of magnitude, and declined with increasing Uair in all feathers. This, along with the presence of strong harmonics, multiple modes of flutter and several other non-linear effects indicates that flutter is not simply a vortex-induced vibration, and that the accompanying sounds are not vortex whistles. Flutter is instead aeroelastic, in which structural (inertial/elastic) properties of the feather interact variably with aerodynamic forces, producing diverse acoustic results.

Medienart:

E-Artikel

Erscheinungsjahr:

2013

Erschienen:

2013

Enthalten in:

Zur Gesamtaufnahme - volume:216

Enthalten in:

The Journal of experimental biology - 216(2013), Pt 18 vom: 15. Sept., Seite 3395-403

Sprache:

Englisch

Beteiligte Personen:

Clark, Christopher J [VerfasserIn]
Elias, Damian O [VerfasserIn]
Prum, Richard O [VerfasserIn]

Links:

Volltext

Themen:

Aeroacoustic
Courtship display
Journal Article
Research Support, U.S. Gov't, Non-P.H.S.
Sonation
Tail
Wind tunnel

Anmerkungen:

Date Completed 05.03.2014

Date Revised 22.08.2013

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1242/jeb.080317

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM228075017