Master of Science (MS), Bowling Green State University, 2016, Physics

Using the Plexiglas Model M5, a static hemilarynx condition was produced using vocal fold pieces housed within a wind tunnel to collect pressure distributions throughout the glottis under constant flow conditions. In order to make the hemilarynx condition, one vocal fold piece was always kept vertical within the glottis, while the other spanned three different glottal angles, one converging, one uniform, and one diverging. The variability of glottal diameter was also introduced and data was collected at 0.01, 0.04, and 0.16 cm diameters. Pressure distributions and flow rates for such configurations are of interest for the analysis of phonation in patients for whom one vocal fold has been immobilized. Flow bistability was introduced at each of the glottal diameters for each glottal angle. Observations regarding the effect that flow bistability had on the pressure distributions showed that a bistable condition of flow produced noticeably less prominent changes in the pressure values intraglottally than the changes in pressures related to the asymmetric angles themselves. The flow bistability therefore created the greatest differences in larger diameter cases. From these pressure distributions, the data can be used in other multimass models to provide insight into the asymmetric forces that may occur within the larynx during phonation.

Committee: Lewis Fulcher Dr. (Advisor); Marco Nardone Dr. (Committee Member); Ronald Scherer Dr. (Committee Member) Subjects: Biophysics; Physics; Speech Therapy

Master of Science (MS), Bowling Green State University, 2010, Physics

Glottal obliquity occurs when the centerline of the glottis is not vertical, a consequence of oscillations of the vocal folds that are not mirror images of each other. This study examined the intraglottal surface pressure distributions for three cases of obliquity: 2.5, 5, and -3.75 degrees, relatively small oblique angles. These correspond to included glottal angles that are convergent, uniform, and divergent, respectively. The Plexiglas model M5 of the laryngeal airway with rectangular glottal ducts and insertable vocal fold pieces was used to obtain the pressure distributions. Glottal diameter and transglottal pressure were primary parameters for each obliquity case. The glottal diameters were 0.005, 0.01, 0.02, 0.04, 0.08, 0.16, and 0.32 cm. The pressure distributions ranged from 3-25 cm H2O for most cases. For each diameter, pressures were measured along both the flow wall (to which the flow jet adheres or was directed) and the non-flow wall (the side opposite the flow wall). Results indicate that the small angle obliquity cases studied here suggest significant pressure distribution differences compared to the symmetric glottis of the same included angle for the following conditions: for the convergent glottis for medium and large diameters; for the uniform glottis for small and for large diameters. However, there was little effect on pressure distributions for the divergent glottis, for small diameters for the convergent glottis, and for medium diameters for the uniform glottis. Relative to diameter change, strong effects were found. As the diameter was reduced, the pressure distributions rose both upstream and in the glottis for the uniform glottis, and increased in the glottis for the convergent glottis. For the divergent glottis, reducing the diameter moved the minimal pressure downstream to the minimal diameter location, and increased the pressures on the inferior vocal fold surfaces. In addition, when the airflow is shifted to change which wall is t (open full item for complete abstract)

Committee: Lewis Fulcher PHD (Committee Chair); Ronald Scherer PHD (Committee Co-Chair); Haowen Xi PHD (Committee Member) Subjects: Physics