Flow kinematics in regions with flow recirculation inside nasal cavity

Abstract

Flow kinematics was investigated in the regions located in the superior (region P) and inferior (region N) meatuses of the human nasal cavity where flow recirculation develops during the respiration period. The region P represents the posterior part of the ethmoidal sinus ostium, which several studies have reported as a frequent site for the development of nasal polyps. Region N located in the airflow passage in the inferior meatus, where polyp rarely form, was also investigated for comparison. Wall shear stress was found to be significantly reduced in both regions due to the development of flow separation, indicating a mechanical irritation of the epithelium by wall shear is likely to be quite suppressed. Even though the region P had a relatively smaller separation bubble, this region was found to have a longer particle residence time, which may increase the exposure time of foreign particles (e.g. allergens, pollen, and various pathogens) to the epithelium of the nasal airway.