Figure 7.

The intranasal fluid dynamics of canine olfaction. (a) Unsteady pathlines generated from trajectories of neutrally buoyant particles released from the naris at equally spaced time intervals throughout inspiration reveal distinct respiratory and olfactory flow paths within the nasal cavity. (b) The same inspiratory pathlines coloured by velocity magnitude show high-velocity olfactory airflow travelling back through the dorsal meatus and low-velocity airflow filtering through the olfactory recess in the forward–lateral direction. (c) Expiratory pathlines originating from the nasopharynx demonstrate that airflow bypasses the olfactory recess during expiration, leaving quiescent scent-laden air there, providing an additional residence time for enhanced odorant absorption. (a) Red lines, olfactory pathlines; blue lines, respiratory pathlines.