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Computer modeling of effects of vocal exercising with a tube on vocal tract sound power transfer
Horáček, Jaromír ; Vampola, T. ; Laukkanen, A. M. ; Švec, J. G.
Two 3D finite element (FE) models were constructed, based on CT measurements of a subject phonating on [a:] before and after phonation into a tube. Acoustic analysis was performed exciting the models by acoustic flow velocity at the vocal folds. The generated acoustic pressure of the response was computed in front of the mouth and inside the vocal tract for both FE models. Average amplitudes of the pressure oscillations inside the vocal tract and in front of the mouth were compared to display a cost-efficiency of sound energy transfer at different formant frequencies. Comparison of the pressure oscillation inside and outside the vocal tract showed that formants differ in their efficiency, F4 (at about 3.5 kHz, i.e. at the speaker’s or singer’s formant region) being the most effective. The results suggest that exercising on semi-occlusions help in improving the vocal economy.
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Numerical tests of flow in human vocal tract
Pořízková, P. ; Kozel, K. ; Horáček, Jaromír
This study deals with a numerical solution of a 2D unsteady flow of a compressible viscous fluid in a channel for low inlet airflow velocity. The unsteadiness of the flow is caused by a prescribed periodic motion of a part of the channel wall with large amplitudes, nearly closing the channel during oscillations. The channel is a simplified model of the glottal space in the human vocal tract. The authors present several numerical tests of computational domain, of modified numerical scheme and types of mesh for the wall motion frequency 100 Hz.
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Mathematical model of the support of experimental aerodynamical profile
Kozánek, Jan ; Bula, Vítězslav ; Zolotarev, Igor
In this paper the simple mathematical model of longitudinal and angular vibrating motion of experimental aerodynamical NACA0015 profile is given. With the help of dynamical experiments from complex frequency responses are by least squares fitting method identified complex eigenvalues. The direct identification method defines real coefficient matrices (of order 2) of stiffness, damping and mass of this non-conservative dynamical system. Finally, the comparisons of measured and from mathematical model evaluated responses are given and discussed.
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