In myoelastic-aerodynamic theory of vocal fold vibration, interaction between air pressure (aerodynamic forces) and elasticity of the vocal folds (myoelastic forces) plays an important role. To focus on the aerodynamic aspect of the vocal fold vibration, we studied a physical model of the vocal folds, the configuration of which switches dynamically between convergent and divergent shapes. In the previous studies of measuring air pressure of dynamically moving vocal fold models, simpler geometries have been utilized. For physical models having realistic geometries, details of the pressure distribution have not been observed. The present study utilized a vocal fold model with M5-geometry, the angle of which changes in time. Pressure sensors and an angle sensor were installed to measure surface pressures of the vibrating vocal folds. The results indicated that, in the convergent shape, the subglottal pressure predominates a wide range of the glottis, while, in the divergent shape, atmospheric pressure dominates the glottis due to a lowered air-jet separation point. These findings confirmed that the switching between the divergent and convergent configurations enhances the opening/closing movements of the vocal folds. We conclude that dynamic transition of the glottal shape plays a crucial role in maintaining vocal fold vibration through aerodynamic forces.
Kumeda et al. (Wed,) studied this question.