A Numerical Simulation of Unsteady Flow in a Quasi-Seesaw Glottal Model

We present a model for forced oscillatory motion of vocal folds. In this model, we incorporate oscillatory motion of the glottis by considering the moments of glottis about its fulcrum point which is very similar to seesaw motion. By changing the position of the fulcrum point, we can have different scenarios for the motion of the glottis. Forced oscillatory motion of vocal folds, together with the solution of Navier-Stokes equations, approximates the flow within an idealized human glottis. Typical results are obtained by considering Reynolds number 1000 for the cases when fulcrum point is in the middle of the glottis and when it divides the glottis in the ratio 1:3. Fulcrum point plays a pivotal role in determining the characteristics of glottal flow. It has strong effect on the central pressure and axial velocity profiles, cross-sectional velocity profiles at the inlet, outlet and within the glottal constriction and formation and structure of vortices in the glottal flow. When the fulcrum point is located nearer the entry section, amplitude of the forward flow at the entry decreases, reverse flow at the outlet is reduced, jet flow is smoothed out at the outlet and flow separation locations are concentrated at the exit.