Flow development in the uniform glottis and viscosity effects

• Main Authors: Fulcher, Lewis P., Scherer, Ronald C.
• Format: Conference Proceeding
• Language: English
• ISSN: 1939-800X
• DOI: 10.1121/1.4800749

Thirty-two pressure distributions at minimal diameters of d = 0.005, 0.0075, 0.01, 0.02, 0.04, 0.08, and 0.16 cm have been measured at a number of transglottal pressures of interest for phonation. Care is taken to identify those portions of the pressure distributions within the glottis that include substantial regions of uniform decrease with axial distance. These portions are further examined to identify their components that have a linear dependence on the volume velocity and those that have a quadratic dependence on the volume velocity. An analysis based on the Navier Stokes equation creates a natural framework for investigating corrections to the parabolic profile of fully developed flow, which leads to the Poiseuille formula. For glottal diameters between 0.0075 cm and 0.02 cm the Poiseuille formula is a good approximation. Overall, an inverse 2.59 power law to describe the diameter dependence of the linear coefficients is found to be superior to the inverse cube dependence of the Poiseuille formula. Glottal flow resistance is used as a means of comparing the accuracy of the two power laws.