Aerodynamic sound generation of flapping wing

Youngmin Bae, Young June Moon

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

The unsteady flow and acoustic characteristics of the flapping wing are numerically investigated for a two-dimensional model of Bombus terrestris bumblebee at hovering and forward flight conditions. The Reynolds number Re, based on the maximum translational velocity of the wing and the chord length, is 8800 and the Mach number M is 0.0485. The computational results show that the flapping wing sound is generated by two different sound generation mechanisms. A primary dipole tone is generated at wing beat frequency by the transverse motion of the wing, while other higher frequency dipole tones are produced via vortex edge scattering during a tangential motion. It is also found that the primary tone is directional because of the torsional angle in wing motion. These features are only distinct for hovering, while in forward flight condition, the wing-vortex interaction becomes more prominent due to the free stream effect. Thereby, the sound pressure level spectrum is more broadband at higher frequencies and the frequency compositions become similar in all directions.

Original languageEnglish
Pages (from-to)72-81
Number of pages10
JournalJournal of the Acoustical Society of America
Volume124
Issue number1
DOIs
Publication statusPublished - 2008 Jul 25

Fingerprint

flapping
aerodynamics
wings
acoustics
hovering
flight conditions
vortices
dipoles
beat frequencies
unsteady flow
free flow
flow characteristics
sound pressure
Aerodynamics
Sound
Flapping
two dimensional models
Mach number
Reynolds number
broadband

ASJC Scopus subject areas

  • Acoustics and Ultrasonics

Cite this

Aerodynamic sound generation of flapping wing. / Bae, Youngmin; Moon, Young June.

In: Journal of the Acoustical Society of America, Vol. 124, No. 1, 25.07.2008, p. 72-81.

Research output: Contribution to journalArticle

@article{b200e84dd1914850851a6444e216ad00,
title = "Aerodynamic sound generation of flapping wing",
abstract = "The unsteady flow and acoustic characteristics of the flapping wing are numerically investigated for a two-dimensional model of Bombus terrestris bumblebee at hovering and forward flight conditions. The Reynolds number Re, based on the maximum translational velocity of the wing and the chord length, is 8800 and the Mach number M is 0.0485. The computational results show that the flapping wing sound is generated by two different sound generation mechanisms. A primary dipole tone is generated at wing beat frequency by the transverse motion of the wing, while other higher frequency dipole tones are produced via vortex edge scattering during a tangential motion. It is also found that the primary tone is directional because of the torsional angle in wing motion. These features are only distinct for hovering, while in forward flight condition, the wing-vortex interaction becomes more prominent due to the free stream effect. Thereby, the sound pressure level spectrum is more broadband at higher frequencies and the frequency compositions become similar in all directions.",
author = "Youngmin Bae and Moon, {Young June}",
year = "2008",
month = "7",
day = "25",
doi = "10.1121/1.2932340",
language = "English",
volume = "124",
pages = "72--81",
journal = "Journal of the Acoustical Society of America",
issn = "0001-4966",
publisher = "Acoustical Society of America",
number = "1",

}

TY - JOUR

T1 - Aerodynamic sound generation of flapping wing

AU - Bae, Youngmin

AU - Moon, Young June

PY - 2008/7/25

Y1 - 2008/7/25

N2 - The unsteady flow and acoustic characteristics of the flapping wing are numerically investigated for a two-dimensional model of Bombus terrestris bumblebee at hovering and forward flight conditions. The Reynolds number Re, based on the maximum translational velocity of the wing and the chord length, is 8800 and the Mach number M is 0.0485. The computational results show that the flapping wing sound is generated by two different sound generation mechanisms. A primary dipole tone is generated at wing beat frequency by the transverse motion of the wing, while other higher frequency dipole tones are produced via vortex edge scattering during a tangential motion. It is also found that the primary tone is directional because of the torsional angle in wing motion. These features are only distinct for hovering, while in forward flight condition, the wing-vortex interaction becomes more prominent due to the free stream effect. Thereby, the sound pressure level spectrum is more broadband at higher frequencies and the frequency compositions become similar in all directions.

AB - The unsteady flow and acoustic characteristics of the flapping wing are numerically investigated for a two-dimensional model of Bombus terrestris bumblebee at hovering and forward flight conditions. The Reynolds number Re, based on the maximum translational velocity of the wing and the chord length, is 8800 and the Mach number M is 0.0485. The computational results show that the flapping wing sound is generated by two different sound generation mechanisms. A primary dipole tone is generated at wing beat frequency by the transverse motion of the wing, while other higher frequency dipole tones are produced via vortex edge scattering during a tangential motion. It is also found that the primary tone is directional because of the torsional angle in wing motion. These features are only distinct for hovering, while in forward flight condition, the wing-vortex interaction becomes more prominent due to the free stream effect. Thereby, the sound pressure level spectrum is more broadband at higher frequencies and the frequency compositions become similar in all directions.

UR - http://www.scopus.com/inward/record.url?scp=47649108919&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=47649108919&partnerID=8YFLogxK

U2 - 10.1121/1.2932340

DO - 10.1121/1.2932340

M3 - Article

C2 - 18646956

AN - SCOPUS:47649108919

VL - 124

SP - 72

EP - 81

JO - Journal of the Acoustical Society of America

JF - Journal of the Acoustical Society of America

SN - 0001-4966

IS - 1

ER -