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Sound generation by steady flow through glottis-shaped orifices
Zhaoyan Zhang1, Luc Mongeau, Steven H Frankel
1Ray W Herrick Laboratories, Purdue University, West Lafayette, Indiana 47907-1077, USA. zhaoyan@glue.umd.edu
The Journal of the Acoustical Society of America
|October 14, 2004
Summary
This study investigates broadband sound generation from human-like vocal fold models. It reveals how turbulence and vocal fold forces create sound, with quadrupole sources dominating most configurations.
Area of Science:
- Acoustics
- Fluid Dynamics
- Bioacoustics
Background:
- Human voice production involves both tonal and broadband sound components.
- Broadband sound generation is primarily attributed to turbulent quadrupole sources and vocal fold-induced dipole sources downstream of the glottis.
Purpose of the Study:
- To experimentally characterize broadband sound emissions from confined jets mimicking the human glottis.
- To analyze the influence of varying flow rates, orifice shapes, and gas mixtures on sound spectra.
Main Methods:
- Experiments used rubber orifices simulating glottal shapes at different vibration cycle stages.
- Radiated sound pressure spectra were measured downstream of the orifices.
- Nondimensional sound pressure spectra were decomposed into source, radiation efficiency, and acoustic response functions.
Main Results:
- Quadrupole source contributions were dominant for straight and convergent orifices, similar to circular jets.
- Divergent orifices produced whistling tonal sounds at low flow rates and dipole-dominated sound at high flow rates.
- Acoustic feedback in confined flows may have affected accurate source identification.
Conclusions:
- The study provides insights into the physical mechanisms of broadband sound production in the human voice.
- Findings highlight the distinct acoustic behaviors of different glottal geometries and flow conditions.
- Further research is needed to fully understand source-load acoustic feedback effects in vocal fold acoustics.