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NUMERICAL SIMULATION OF LARYNGEAL FLOW
Citation:
Zhang, Z., T. Martonen, AND R. Lessmann. NUMERICAL SIMULATION OF LARYNGEAL FLOW. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-95/115.
Description:
In this study, we have investigated laryngeal air flows by numerically solving the corresponding Navier-Stokes equations expressed in a two-dimensional cylindrical coordinate system. The glottal aperture, defined by the geometry of the vocal folds was allowed to change with the volumetric rate of inspiration flow. Three flow rates which corresponded to different levels of human activity were examined. Moreover, physiologically realistic geometries of the larynx and primary lung bifurcation were included in our model. Numerical simulations have shown that there is a very focused region of high velocity in the center of the trachea, extending from its length. The centerline velocity may be as much as one order of magnitude greater than the mean inlet velocity. The pressure drop within larynx flow is not monotonically related to the volumetric flow rate. Rather, it depends upon the particular flow patterns, which are functions of both flow rate magnitude and laryngeal geometries. The pressure drip at certain locations may actually reduced for increased volumetric flow rate. The flow patterns within the main bronchial bifurcation zone could be very complicated depending on inspiration flow rate values, vocal fold openings, and laryngeal geometries.