Flow mechanisms in the human olfactory groove numerical simulation of nasal physiological respiration during inspiration, expiration, and sniffing

Objectives: To visualize the velocity and the streamline of physiological unsteady nasal flow and sniffing using the computational fluid dynamics method and to compare the inspiratory phase, expiratory phase, and sniffing flow patterns of the olfactory area. Design: An anatomically correct 3-dimensional nasal and pharyngeal cavity was constructed from computed to-mographic images of a healthy adult nose and pharynx. The unsteady state Navier-Stokes and continuity equations were solved numerically on inspiratory and expiratory nasal flow and sniffing. Setting: Numerical simulation application. Main Outcome Measures: The detailed velocity dis-tribution and streamline distribution of nasal airflow were visualized using the computational fluid dynamics method (an imaging technology for regional flow factors [veloc ity and streamline]). Results: The inspiratory flow passes through a wider olfactory area than the expiratory flow, and the sniffing flow passes through the widest olfactory area without increasing the velocity of the airflow. In addition, a recirculating flow strongly promotes olfactory function. Conclusion: The computational fluid dynamics model allows for the investigation of the flow mechanisms in the human olfactory groove.