Assessment of septal deviation effects on nasal air flow: a computational fluid dynamics model.

OBJECTIVES/HYPOTHESIS: The purpose of this article is to analyze the effects of septal deviation on the aerodynamic air flow pattern compared with that of a normal nose by computational fluid dynamics (CFD) tools.

METHODS: Two 3-dimensional (3-D) models of nasal cavities were constructed from the magnetic resonance imaging and computed tomography scans of a healthy human nose and a nose with septal deviation, with the use of the software MIMICS 12.1 (The Materialise Group, Leuven, Belgium). Thereafter high-resolution 3-D volume meshes comprising boundary layer effect and computational domain exterior to the nose were constructed. Numerical simulations were carried out using FLUENT (ANSYS, Canonsburg, PA) for CFD simulations. The Reynolds-averaged Navier-Stokes equations were solved for the turbulence flow with the shear stress transport k - omega model.

RESULTS: In the nose model with septal deviation, major changes in the pattern of inspiratory airflow (e.g., flow partitioning and nasal resistance, velocity and pressure distributions, intensity and location of turbulence), wall shear stress, and increasing of total negative pressure through the nasal cavity were demonstrated qualitatively and quantitatively. In the healthy nose, the area with the highest intensity of turbulent flow was found in the functional nasal valve region, but it became less apparent or even disappeared in the septal deviation one.

CONCLUSIONS: This CFD study provides detailed information of the aerodynamic effects of nasal septal deviation on nasal airflow patterns and their associated physiological functions.