Fluid Dynamics of Human Phonation and Speech

Abstract

This article presents a review of the fluid dynamics, flow-structure interactions, and acoustics associated with human phonation and speech. Our voice is produced through the process of phonation in the larynx, and an improved understanding of the underlying physics of this process is essential to advancing the treatment of voice disorders. Insights into the physics of phonation and speech can also contribute to improved vocal training and the development of new speech compression and synthesis schemes. This article introduces the key biomechanical features of the laryngeal physiology, reviews the basic principles of voice production, and summarizes the progress made over the past half-century in understanding the flow physics of phonation and speech. Laryngeal pathologies, which significantly enhance the complexity of phonatory dynamics, are discussed. After a thorough examination of the state of the art in computational modeling and experimental investigations of phonatory biomechanics, we present a synopsis of the pacing issues in this arena and an outlook for research in this fascinating subject. 437

Comments on “A theoretical model of the pressure field arising from asymmetric intraglottal flows applied to a two-mass model of the vocal folds” [J. Acoust. Soc. Am. 130, 389–403 (2011)]

“…An alternative model is proposed, which avoids these problems and predicts that there is a minimum glottal opening below which the walljet does not separate from the wall at the glottal exit. This is in agreement with the experimental results provided by Erath et In a series of recent papers Erath et al [1][2][3] consider the interesting problem of the asymmetry of the flow in the downstream part of the glottis during the closing phase of the vocal fold oscillation cycle. The glottis is then a slit shaped converging-diverging channel with a neck (width a min ) at the upstream side of the glottis.…”

“…The build-up and maintenance of this asymmetric flow is referred to as the Coanda effect. [4][5][6] While Mittal et al 3 does not like this terminology, we will use it because it is the most commonly used by fluid dynamicists.…”

“…2 Combining this with a simplified two-mass lumped element model for the dynamics of the vocal folds, they estimate the influence of the asymmetry on the movement of the folds. 2 Mittal et al 3 place this work in a broader context and provide a review of literature on the subject. The work done and, in particular, the use of a simplified model allowing a quantitative discussion of the problem is greatly appreciated.…”

Instabilities in flexible channel flow with large external pressure

“…The system considered herein, flow-driven oscillations about a highly collapsed static configuration is reminiscent of instabilities generated by fluid-structure interaction in the vocal folds in the human larynx (see Mittal et al 2013, for a recent review), with the external pressure playing the role of the tissue pressure in the folds. A qualitative comparison between our predictions and experiments on mechanical replica of the human vocal tract is an interesting direction for future work.…”

Intraglottal velocity and pressure measurements in a hemilarynx model

“…Thus, almost all of our understanding of intraglottal aerodynamics is derived from mechanical, analytical, and computational models. The reader is referred to Mittal et al (2013) for a summary of the progress that was made in computational and experimental models used to study the aerodynamics of the vocal folds vibrations.…”