Three-dimensional fluid particle trajectories in the human larynx and trachea.

A computational fluid dynamics software package (FIDAP) has been employed to obtain three-dimensional flow data, which are used herein to calculate the trajectories of fluid particles. Our computations have demonstrated that the flow fields inside the larynx are very complex including eddies in the lumen and reverse motion along the surface. The effects of such flow fields will be to increase the residence times of entrained drug particles. Our computations have also demonstrated that the larynx has pronounced effects on the motion of air in the trachea.