DAGA 2010 - Deutsche Gesellschaft für Akustik eV

60 DAGA 2010 Programm
positions in the anterior-posterior axis of the vocal folds. First results obtained
from the FE simulations are shown.
Di. 16:35 Gauß B 554 Stimmphysiologie
Numerical study of the acoustic sources inside the human larynx
by the Finite Element Method
S. Zörner a , M. Kaltenbacher a , R. Lerch b und M. Döllinger c
a Alps-Adriatic University of Klagenfurt; b Univ. Erlangen-Nürnberg, Lehrstuhl
für Sensorik; c Abteilung für Phoniatrie, Universitätsklinikum Erlangen
Human phonation is the result of the interaction of different physical
fields. Fluid flow through the trachea generates vibrations of the vocal
folds, which are positioned inside the larynx. Therewith, fluid flow as
well as me- chanical vibrational induced sound is produced. A numerical
scheme based on the 2d Finite Element method will be pre- sented,
which allows to reveal the different mechanisms of voice produc- tion.
Our investigations prove that the main parts within the primary acous- tic
signal are generated by fluid flow. However, the vibration induced sound
generated by the oscillations of the vocal folds plays a minor role. Concerning
the flow induced sound, we may distinguish between the pulsating
flow driven by the vocal folds oscillations and strong variations of
fluid flow velocities due to the Coanda effect. The first phenomena induces
a tonal signal, whereas the second phenomena generates vortices
of different scales producing a broadband acoustic signal.
Di. 17:00 Gauß B 554 Stimmphysiologie
Sensitivity of Aeroacoustic Source Distribution for Different Glottal
Motion Patterns
W. Mattheus a , S. Zörner b , M. Triep a , M. Stingl c , M. Döllinger d , R.
Schwarze a , M. Kaltenbacher b und C. Brücker a
a Institut für Mechanik und Fluiddynamik, TU Bergakademie Freiberg;
b Alps-Adriatic University of Klagenfurt; c Univ. Erlangen-Nürnberg, Lehrstuhl
f. Angew. Mathematik II; d Abteilung für Phoniatrie, Universitätsklinikum
Erlangen
The modulation of the air flow resulting from the oscillation pattern of the
human vocal folds represents the main acoustic source in human voice
generation. The present investigation uses a three-dimensional numerical
model of the vocal folds and shows the connection between glottal
motion pattern, the supraglottal flow field and the flow induced acoustic
field. In a hybrid approach the Navier-Stokes equations for incompressible
fluid flow are numerically solved and the aeroacoustic source
terms for the inhomogeneous wave equation are determined by Lighthill’s
acoustic analogy. Coherent flow structures generated in the shear
layer of the supraglottal jet flow and small-scale fluctuations occurring
during the turbulent decay of the jet contribute to the acoustic source
terms in the supraglottal flow field. In case of asymmetric vocal folds