Analysis of the human phonation with different vocal fold geometries by applying a two-dimensional fully coupled fluid-solid-acoustic finite element scheme.

Abstract

A numerical two-dimensional model is presented simulating the human laryngeal voice production. Air flowing through the larynx interacts with the structural mechanics of the vocal folds forcing them to vibrate and induce sound. In turn, the vibrations of the vocal folds cause the airflow to pulsate which acts as a further sound source inside the larynx. This coupled field problem is modeled by utilizing an enhanced finite element method. The presented approach takes all three involved physical fields consisting of fluid mechanics, solid mechanics, acoustics, and their interactions fully into account. The results of these simulations clearly demonstrate the impact of different vocal fold geometries on the fluid field, e.g., changing the occurrence of the Coanda effect. In addition, influences on the produced sound signal resulting in modified main acoustic frequencies are observed. An additional eigenfrequency analysis on the vocal fold model was performed showing that the first eigenmode and the vibrational frequency in the transient case are identical. The first eigenmode was in the range of about 100 Hz depending on the vocal fold geometry.