Archives of Acoustics, 36, 1, pp. 15–27, 2011

A One-Mass Physical Model of the Vocal Folds with Seesaw-Like Oscillations

Tahir Mushtaq QURESHI
Bahauddin Zakariya University Center for Advance Studies in Pure and Applied Mathematics

Khalid Saifullah SYED
Bahauddin Zakariya University Center for Advance Studies in Pure and Applied Mathematics

A low-dimensional physical model of small-amplitude oscillations of the vocal
folds is proposed here. The model is a simplified version of the body-cover one in
which mucosal surface wave propagation has been approximated by the seesaw-like
oscillation of the vocal fold about its fulcrum point whose position is adjustable in
both the horizontal and vertical directions. This approach works for 180 degree
phase difference between the glottal entry and exit displacements. The fulcrum
point position has a significant role in determining the shape of the glottal flow.
The vertical position of the fulcrum point determines the amplitude of the glottal
exit displacement, while its horizontal position governs the shape and amplitude of
the glottal flow. An increment in its horizontal position leads to an increase in the
amplitude of the glottal flow and the time period of the opening and closing phases,
as well as a decrease in the time period of the closed phase. The proposed model is
validated by comparing its results with the low-dimensional mucosal surface wave
propagation model.
Keywords: body-cover model; seesaw-like oscillation; glottal flow; vocal folds; springmass system; mucosal wave propagation
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