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Unsteady flow through in-vitro models of the glottis
G C J Hofmans1, G Groot, M Ranucci
1Fluid Dynamics Laboratory, Faculty of Applied Physics, Eindhoven University of Technology, Postbus 513, 5600 MB Eindhoven, The Netherlands.
The Journal of the Acoustical Society of America
|March 27, 2003
Summary
This study validates a boundary-layer separation model for glottic flow using rigid models. Complex flow phenomena like Coanda effect and turbulence are unlikely during normal speech due to glottis closure.
Area of Science:
- Fluid dynamics
- Bioacoustics
- Aerodynamics
Background:
- Understanding glottic flow is crucial for voice production.
- Existing models require validation with experimental data.
- In vitro models allow precise study of glottic geometry and flow dynamics.
Purpose of the Study:
- To validate a boundary-layer separation model for unsteady, two-dimensional glottic flow.
- To investigate flow phenomena within rigid glottis models, excluding vocal fold movement.
- To compare experimental pressure measurements with theoretical model predictions.
Main Methods:
- Utilized unsteady, two-dimensional flow through fixed, rigid glottis models.
- Performed transient pressure measurements on a rigid scale model.
- Employed a boundary-layer model and a two-dimensional vortex-blob method for comparison.
Main Results:
- Boundary-layer model predictions align within 40% with experimental pressure drop measurements for laminar, symmetric flow.
- Coanda effect and transition to turbulence require significant time to establish, making them unlikely during normal voiced speech.
- Discrepancies between the boundary-layer model and experimental results are attributed to downstream pressure differences.
Conclusions:
- The validated boundary-layer model offers improved accuracy for glottic flow prediction.
- Complex flow phenomena are unlikely during normal speech due to glottis dynamics.
- Further research is needed to clarify the influence of vocal fold movement on glottic flow dynamics.