Experimental study of velocity fields in a human nasal fossa by laser anemometry.

Velocity fields were mapped in a model of a human nasal fossa by laser doppler velocimetry, an innovative, quantitative and noninvasive method of optical anemometry, and by computerization. Other pertinent parameters were also calculated. Studies made at different cross sections of the nasal fossa showed the very definite influence not only of shapes and dimensions but also of direction of flow on velocity fields. The turbinates had a streamlining effect on the velocity fields while the liminal valve had a directional effect. Flow was usually greater in the lower half of the fossa and closer to the septum. The flow was generally turbulent. Velocity fields appear to give more information on intranasal aerodynamics than the calculated flow and Reynolds number for the sections studied, and this allows one to at least theorize that there may be an aerodynamic basis to certain pathological conditions of the nasal airway and its adjoining cavities, the paranasal sinuses, and the eustachian tubes.