On the accuracy of 1-D flow models in predicting vocal fold oscillation and voice production

While the airflow through the glottis has been shown to be highly 3-D, 1-D flow models are widely used in voice production studies, due to their computational efficiency. In a series of studies, we evaluated the accuracy of a 1-D flow model in predicting vocal fold oscillation and voice production in both left–right symmetric and asymmetric vocal fold conditions. The 1–D flow model calculates the glottal flow based on Bernoulli’s equation, coupled to an equivalent circuit model of the vocal tract, and a vocal fold model of varying degree of complexity, including a two-mass model and a 3-D continuum vocal fold model. The predicted voice outcomes were compared to experimental observations and predictions from simulations solving the 3-D compressible Navier–Stokes flow equations. The comparison showed that the 1-D flow model reproduced both the overall vibration patterns and specific voice measures observed in the experiments and three-dimensional flow simulations. These results suggest that while glottal flow is essential to initiate vocal fold oscillation, the vibration pattern is more strongly influenced by vocal fold geometry and tissue properties than by the details of the airflow around the vocal folds.