Effect of channel asymmetry on the behavior of flow passing through the glottis

Abstract

A method for analyzing the behavior of flow passing through an asymmetrical glottal channel is presented. The method assumes the formation of a thin boundary layer near the glottal wall and an interaction between the boundary layer and the core flow. The core flow velocity is estimated in two dimensions employing a method of potential flow analysis, while the characteristic quantities of the boundary layer are determined by solving the integral momentum relation on the basis of the similarity of the velocity profiles within the layer. Estimation results for the volume flow rate, effective flow velocity, pressure distribution, driving force of the vocal folds, and flow separation point are presented for a total of 315 glottal configurations obtained by varying the angle of each vocal fold and the minimum glottal height. The results indicate that the boundary layer tends to reduce the effect of channel asymmetry, and the imbalance of the aerodynamic quantities between the two vocal folds is small unless the glottis widely opens and the angular difference of the vocal folds is considerable.