Numerical study of inspiratory and expiratory flow in a human nasal cavity

The complicated architecture associated with the nasal anatomy makes it difficult for visualization and measurement of flow parameters inside the nasal cavity. Objective measurement devices like rhinomanometry or acoustic rhinometry fail to assist the understanding of the physiology at every location within the nasal cavity. Therefore, in order to visualize the flow features inside the nasal cavity and to compare the inspiratory phase and expiratory phase in terms of parameters like velocity, resistance, wall shear stress, vortex formation and turbulence intensity, a computational fluid dynamics study was carried out. This study presents, the usefulness of a technique based on functional imaging and computational fluid dynamics (CFD) modeling in generating useful data that can be used to determine and diagnose upper-airway conditions. Variations in flow patterns and flow features such as pressure drop, velocity and the left and right cavity were observed. Resistance to flow was greater during inspiratory phase when compared to the expiratory phase. Turbulence intensity was more predominant during expiratory phase, whereas vortex formation could be observed only during the inspiration mechanism.