The purpose of the present study is to clarify the effects of unsteady glottal flow on the phonation. We numerically simulate the speech production process within the larynx and the vocal tract based on our proposed glottal sound source model. The simulation shows amplitude and waveform fluctuations in pressure within the larynx caused by unsteady fluid motion. In order to investigate the unsteady motion effects on the phonation, the coefficient of variation (CV) of amplitude and harmonic-to-noise ratio (HNR) in terms of measures of fluctuations are estimated. The CV and the HNR indicate the greatest fluctuation near the glottis, although the CV and the HNR do not show the fluctuation faraway from the glottis.
Bibliographic reference. Nomura, Hideyuki / Funada, Tetsuo (2007): "Effect of unsteady glottal flow on the speech production process", In INTERSPEECH-2007, 1390-1393.