Unravelling jet dynamics associated with incomplete glottal opening

This study focuses on the effects of glottal jet dynamics on phonation when one of the vocal folds does not move as much as the other. This can be a pathological condition in which a vocal fold is partially/completely paralyzed, parysis, but also occurs naturally particularly with aging. Physiological effects include hoarseness, pain, or fatigue in speaking. Data were collected from a scaled-up (10x), 2-D vocal-fold model with semi-circular ends that were computer driven inside a square duct with constant opening and closing speeds. The working fluid was water. Cases in which one vocal fold moved 0%, 50%, 75%, and 100% of the other were examined; the last case being, of course, the nominally 'healthy', symmetric case. Time resolved DPIV and pressure measurements along the duct centerline made at Re = 7200 and reduced frequency of 0.0261 (corresponding to an equivalent life frequency of 97.5 Hz) were used to generate time traces of terms in the integral streamwise momentum equal. Examination of these traces revealed that differences in glottal opening speed, dh/dt, boundary layer blockage, and asymmetry are all factors in the glottal jet dynamics. The focus of this presentation will be on identifying and unravelling these different effects.