ASA 128th Meeting - Austin, Texas - 1994 Nov 28 .. Dec 02

5aSP3. A Navier--Stokes solution of laryngeal flow during vocal fold oscillations.

Fariborz Alipour

Ingo Titze

Dept. of Speech Pathol. and Audiol. and the Natl. Ctr. for Voice and Speech, Univ. of Iowa, Iowa City, IA 52242-1012

Dynamic modeling of vocal fold tissue movement and laryngeal airflow was combined in a computer simulations for the purpose of voice production. A finite-element model was used for the solution of tissue mechanics and a finite volume method was used in the solution of Navier--Stokes equations for the airflow. A so-called ``shadow method'' simulated the glottal constriction in the flow model to avoid the complexity of grid movement. The two-dimensional flow equations were solved in an iterative manner until the given transglottal pressure was approximated. The flow solution was then used in the estimation of the aerodynamic forces on the tissue, required in the finite element solution of tissue movement. The results indicate that glottal velocity profiles are parabolic, with maximum velocity in the exiting jet reaching 35 m/s. The time-varying Reynolds number in the glottis can reach up to 1500 at a lung pressure of 8 cm water. The jet velocity waveform is similar to that of an excised larynx and the pressure profiles are similar to those of steady flows in physical models. Also, the displacement of the inferior portion of glottis shows previously described phase differences with the superior portions. [Work supported by NIDCD Grant No. DC00831-03.]