Influences of Cartilaginous Rings on Tracheobronchial Fluid Dynamics

Abstract

Fluid dynamics patterns within tracheobronchial (TB) airways reflect interactions between cartilaginous rings and inspiratory flow rates. The results of supercomputer simulations performed herein were complex, yet systematic. The effects of cartilaginous rings upon TB fluid dynamics patterns were investigated using FIDAP software. A sequence of cartilaginous ring morphologies was examined. The distributions of rings varied from contiguous to spaced. A range of physiologically realistic flow conditions was simulated corresponding to these physical states: sedentary, light, and heavy activity. At the lowest inspiratory flow rate (14 L min⁻¹) the primary convection flow within an airway occupied a prominent portion of its cross-sectional area and ring effects were confined along the rough surface. At the highest inspiratory flow rate (120 L min⁻¹) the core flow was very narrow, with the disturbances created at the irregular walls being propagated to the very center of the airway. The fluid dynamics analyses have applications to both inhalation toxicology programs and aerosol therapy protocols, since the motion of entrained particles will be inherently affected by airstreams.