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S. Zörner, P. Sidlof, A. Hüppe, M. Kaltenbacher:
"Strömung-Struktur-Interaktion in der menschlichen Stimmbildung und korrekte Modellierung der resultierenden aeroakustischen Quellen und Schallausbreitung";
Talk: DAGA 2015, Nürnberg (invited); 2015-03-16 - 2015-03-19; in: "41. Jahrestagung für Akustik", (2015), 50 - 53.

The human phonation is a complex interaction of fluid mechanics, solid mechanics and acoustics.
As the lungs compress, air flows through the larynx passing the vocal folds which form
a narrow constriction, the glottis. The air flow forces the vocal folds to vibrate which in turn
creates a pulsating air stream. The resulting air flow is the main source generating sound - the
phonation.
A fully coupled 3D fluid-structure simulation is not feasible regarding computational costs, since
several iterations are necessary in each time step to reach a state of equilibrium between
the flow and structural mechanical field. Therefore, we present 3D computations applying prescribed
vocal folds vibrations, and analyze the generated acoustic sound in the larynx as well
as outside the mouth. Thereby, we apply an hybrid aeroacoustic approach. In the first step, a
CFD simulation is performed using OpenFoam. Based on the CFD results, various source term
formulations are analyzed (second spatial derivative of classical Lighthill tensor, diveregnce of
Lamb vector, Laplacian of flow pressure, time derivative of flow pressure). Finally, we compute
the acoustic field using our in-house code CFS++ based on the wave equation (WE) as well as
perturbation equations (PE).
The main findings of our investigations can be summerized as follows: (1) Lighthill´s wave
equation computes an overall fluctuating pressure composed of the incompressible flow and the
acoustic pressure; (2) the PE allows for a correct physical computation of the acoustic pressure
within the flow; (3) a new aeroacoustic wave equation based on the perturbation ansatz.

fluid-structure interaction, human phonation, aeroacoustic, sound sources

http://publik.tuwien.ac.at/files/publik_238890.pdf