Rc. Scherer et al., Intraglottal pressure profiles for a symmetric and oblique glottis with a divergence angle of 10 degrees, J ACOUST SO, 109(4), 2001, pp. 1616-1630
Human phonation does not always involve symmetric motions of the two vocal
folds. Asymmetric motions can create slanted or oblique glottal angles. Thi
s study reports intraglottal pressure profiles for a Plexiglas model of the
larynx with a glottis having a 10-degree divergence angle and either a sym
metric orientation or an oblique angle of 15 degrees. For the oblique glott
is, one side was divergent and the other convergent. The vocal fold surface
s had 14 pressure taps. The minimal glottal diameter was held constant at 0
.04 cm. Results indicated that for either the symmetric or oblique case, th
e pressure profiles were different on the two sides of the glottis except f
or the symmetric geometry for a transglottal pressure of 3 cm H2O. For the
symmetric case, flow separation created lower pressures on the side where t
he flow stayed attached to the wall, and the largest pressure differences b
etween the two sides of the channel were 5%-6% of the transglottal pressure
. For the oblique case, pressures were lower on the divergent glottal side
near the glottal entry and exit, and the cross-channel pressures at the glo
ttis entrance differed by 27% of the transglottal pressure. The empirical p
ressure distributions were supported by computational results. The observed
aerodynamic asymmetries could be a factor contributing to normal jitter va
lues and differences in vocal fold phasing. (C) 2001 Acoustical Society of
America.