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Contributions to Proceedings:

S. Zörner, P. Sidlof, A. Hüppe, M. Kaltenbacher:
"Human voiced sound simulation by the acoustic perturbation equations and Lighthill´s analogy";
in: "10th PAN-EUROPEAN VOICE CONFERENCE", issued by: PEVOC; Medical Healthcom spol. s r.o. and the authors, Prag, 2013, (invited), ISBN: 9788026048329, Paper ID 98, 138 pages.



English abstract:
Human voice has its source inside the human larynx, as air is forced through the trachea and starts to pulsate as it interacts with the vocal folds. The pulsating air stream generates the main part of the sound, the phonation, which is then filtered by the vocal tract to modulate it and produce human speech.
We model this phenomena by the corresponding partial differential equations. To compute the flow field, which is confined to the larynx, the open source solver OpenFOAM is employed. The vibration of the vocal folds is considered by using prescribed vocal folds movement. In a separate step, the acoustic source terms are determined, based on the fluid field results and in a last step the acoustic wave propagation is calculated. We compare two approaches, Lighthill´s acoustic analogy and an aeroacoustic analogy based on a perturbation ansatz. The acoustic simulations are performed with the finite element solver CFS++. In order to analyse the acoustic pressure in a propagation region, and not only inside the flow field, a realistic but geometrically
fixed vocal tract geometry is connected to the larynx.
The results show, that between both acoustic approaches, the simulated sound leaving the artificial mouth is in good agreement. However, inside the flow region Lighthill´s acoustic analogy is found to overestimate the acoustic pressure. As this is a hybrid approach the vocal tract can be interchanged, making it possible to examine its effects on the acoustic without repeating the costly fluid simulation.
Furthermore, the presented method is capable of analysing the impact on the radiated sound for different phonation scenarios, which we exploit to analyse insufficient glottis closure and compare convergent/divergent vocal folds position.

Keywords:
vocal folds, vocal tract, aeroacoustic, perturbation equation, Lighthill's analogy

Created from the Publication Database of the Vienna University of Technology.