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Coherent turbulent structures in flow through the human vocal tract
Šidlof, Petr ; Doaré, O. ; Cadot, O. ; Čejka, J.
This paper presents experimental and computational data on the coherent turbulent structures in flow through the human vocal tract. The experimental results were obtained using a 4:1 scaled self-oscillating physical model of vocal folds. Flow velocity fields in the coronal plane were visualized and measured using a PIV system phase-synchronized with vocal fold vibration. Computational results originate from finite volume discretizations of viscous incompressible Navier-Stokes equations in 2D and 3D. The results reveal flow separation in the divergent part of glottis and formation of a planar jet. Vortex structures are shed from the shear layer of the jet and convected further downstream. The computational model helps to assess the influence of the ventricular folds on the flow patterns.
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Matematické a fyzikální modelování prouděním vyvolaného kmitání lidských hlasivek
Šidlof, Petr ; Doaré, O. ; Cadot, O. ; Chaigne, A. ; Horáček, Jaromír
the pressure and velocity fields in coronal plane along the vibrating vocal folds were studied using a finite element mathematical model. The shapes of the vocal folds were specified according to data measured on excised human larynges in phonation position. The mathematical model of the flow is based on 2D incompressible Navier-Stokes equations adapted to deal with the time-variable shape of the domain, caused by vocal fold vibration. The numerical simulations allow to observe closely various flow features related to phonation - flow separation in the glottis, Coanda effect or vortex shedding.
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PIV měření proudění kolem samobuzeně kmitajícího modelu hlasivek
Šidlof, Petr ; Doaré, O. ; Cherfa, L. ; Lahcene, Ch. ; Chaigne, A. ; Horáček, Jaromír
A new mechanical model of vocal folds was developed in cooperation with Ecole Nationale Supérieure de Techniques Avancées, Paris. Under specific conditions, the model exhibits flow-induced vibrations, where the vocal folds collide in each cycle. The model was designed to allow dynamic, acoustic and PIV measurements synchronized with the vocal fold oscillations. The results provide interesting information about the vocal fold dynamics and about the nonstationary flow structures, developing downstream the glottis, which closes periodically.
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