Numerical study of the effect of the nasal cycle on unilateral nasal resistance

• Effect of nasal cycle on unilateral nasal resistance was analyzed using CFD technique.
• Spatial variation of unilateral nasal resistance was analyzed.
• Maximum resistance occurred in the region near nasal valve or in the nasal vestibule.
• Relative importance of resistance in the turbinated air passage depended on nasal cavity models.
• Backflow in inferior meatus resulted in reduced flow rate.

We used computational fluid dynamics to study the effects of the nasal cycle on the modification of unilateral nasal resistance using nasal cavity models from 2 different patients with chronic rhinosinusitis. A steady airflow field with an inspiratory flow rate of 250 mL/s was simulated using ANSYS-FLUENT v14.5. The distribution of local unilateral nasal resistance showed different shapes of variation and magnitudes of resistance depending on the distribution of cross-sectional area in the nasal cavity models. The highest local resistance on the congested side was found near the nasal valve area in the first patient, whereas the highest value was found in the nasal vestibule for the second patient. The relative importance of nasal resistance in the turbinated air passage differed for the 2 patients. The unilateral resistance of the congested state was in the range of 0.0229–0.221 Pa s/mL. In the inferior meatus, greater flow rate was allowed during the congested state than during the decongested state if an extensive backflow developed.