Influence of a constriction in the near field of the vocal folds: Physical modeling and experimental validation

Abstract

The involvement of the ventricular folds is often observed in human phonation and, in particular, in pathological and or some throat-singing phonation. This study aims to explore and model the possible aerodynamic interaction between the ventricular and vocal folds using suitable in vitro setups allowing steady and unsteady flow conditions. The two experimental setups consist of a rigid and a self-oscillating vocal-fold replica, coupled to a downstream rigid ventricular-fold replica in both cases. A theoretical flow modeling is proposed to quantify the aerodynamic impact of the ventricular folds on the pressure distribution and thereby on the vocal-fold vibrations. The mechanical behavior of the vocal folds is simulated by a distributed model accounting for this impact. The influence of the ventricular constriction is measured in both flow conditions and compared to the model outcome. This study objectively evaluates the additional pressure drop implied by the presence of a ventricular constriction in the larynx. It is demonstrated that such constriction can either facilitate or impede the glottal vibrations depending on the laryngeal geometrical configuration. The relevance of using static or dynamic vocal-fold replicas is discussed.

On the acoustic effects of the supraglottic structures in excised larynges

“…In other words it oscillated easier, suggesting that canine SGSs do not help its phonation. This is consistent with the findings of Bailly et al (2008).…”

“…The aerodynamic interaction between the FVFs and the TVFs was studied by Bailly et al (2008) using an experimental set-up with static and dynamic TVFs and fixed FVFs separated by a large and long ventricle. They also analyzed the aerodynamic effects of the FVFs using the Bernoulli equation.…”

Reply to Letter to the Editor

“…Also this is shown by a large number of authors who try to come up with at least ''a small contribution'' to help clarify the function of the vocal folds. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] Then it is difficult of course to trust some articles published, which present very ''authoritative'' conclusions regarding the properties and function of the vocal folds and possible variations of this function.…”

“…As an example, there can be used principle of myoelasto aerodynamic principle of vocal folds function presented in the literature till this time. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] To complete the reliable analysis of a complex phenomenon which the source voice generation undoubtedly is and which has not been reliably resolved in the literature so far, other possible concepts of the examined effect and problem need to be sought without prejudice if possible and presented with impartiality.…”

Letter to the Editor

“…They have added significantly to our understanding of many aspects of vocal behavior of the larynx and clarified important details of the vocal product. [2][3][4][5][6][7][8][9][10][11] In general, however, this approach to the study of phonation has serious limitations about which researchers need to be (and generally are) forthright. Conclusions drawn from the study of physical models need to be constrained by the specific circumstances of the particular experiment and must not extend beyond what the experimental data can justify.…”