CORRELATIONS BETWEEN FLOW RESISTANCE AND GEOMETRY IN A MODEL OF THE HUMAN NOSE

The relationship between the pressure losses within the nasal airways and nasal geometry were studied in a 3:1 scale model. The geometry of the model was based on magnetic resonance images of the skull of a hea lthy male subject. Pressure measurements, flow visualization, and hot- wire anemometry studies were performed at flow rates that, in vivo, co rresponded to flows of between 0.05 and 1.50 I/s. The influence of nas al congestion and the collapse of the external nares were examined by using modeling clay to simulate local constrictions in the cross secti on. A dimensionless analysis of the pressure losses within three secti ons of the airway revealed the influence of various anatomic dimension s on nasal resistance. The region of the exterior nose behaves as a co ntraction-expansion nozzle in which the pressure losses are a function of the smallest, cross-sectional area. Losses in the interior nose re semble those associated with channel flow. The nasopharynx is modeled as a sharp bend in a circular duct. Good correspondence was found betw een the predicted and actual pressure losses in the model under condit ions that simulated local obstructions and congestion.