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Asymmetric glottal jet deflection: differences of two- and three-dimensional models
Willy Mattheus1, Christoph Brücker
1Department of Mechanics and Fluid Dynamics, TU Bergakademie Freiberg, Lampadiusstrasse 4, 09599 Freiberg, Germany. willy.mattheus@imfd.tu-freiberg.de
The Journal of the Acoustical Society of America
|January 10, 2012
Summary
Simulations of airflow through an oscillating glottal-gap reveal that orifice shape significantly impacts jet deflection. Slit-like geometries cause asymmetric deflection, unlike lens-like ones, influencing phonation dynamics.
Area of Science:
- Fluid dynamics
- Bioacoustics
- Biomechanics
Background:
- Human phonation involves complex airflow dynamics within the glottis.
- The glottal-gap's oscillating motion and geometry are critical for sound production.
- Understanding these dynamics can inform treatments for voice disorders.
Purpose of the Study:
- To investigate the influence of glottal orifice geometry on airflow patterns during phonation.
- To analyze jet deflection and vortex dynamics in relation to orifice shape.
- To assess the role of the Coanda effect in human phonation.
Main Methods:
- Computational fluid dynamics (CFD) simulations were performed.
- Oscillating orifice models (2D slit-like and 3D lens-like) were used.
- Prescribed flow and wall-motion conditions mimicked glottal-gap movement.
Main Results:
- Asymmetric jet deflection was observed for the slit-like orifice geometry.
- The 3D lens-like orifice showed symmetric jet behavior.
- Orifice geometry was found to influence jet entrainment and vortex dynamics.
Conclusions:
- Glottal orifice geometry plays a crucial role in airflow behavior during phonation.
- Asymmetric jet deflection, potentially linked to the Coanda effect, is geometry-dependent.
- These findings contribute to a deeper understanding of the biomechanics of human voice production.
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