Form and flow in the nasal cavity
The human airways have typically stimulated a smaller portion of
research compared to the circulatory system, and in particular the
arterious system. The result is that much still needs to be
understood about the nasal cavity and its geometric properties. The
interest in studying the nasal cavity is to increase the
understanding in respiratory physiology for further possible
applications of surgery, drug delivery and toxicology. The nasal
cavity has the complex physiological function of conditioning (heat
transfer and humidification) and filtering the inspired air, as
well as to give a sense of olfaction. The result is a complex
geometry that is seen to vary greatly between subjects. The work
presented here is the result of recent studies in coming to terms
with the topology and characterising the nasal airway. Starting
from CT medical image data, anatomically accurate virtual models of
three subjects are obtained for this study. By means of
skeletonisation techniques, Fourier descriptors and implicit
functions we are able to deconstruct the topology of these patients
as a set of signals. From these we formulate an average nasal
airway geometry and describe the individual subjects as a deviation
from the mean. The underlying interest in studying the topology is
to learn about the flow field. CFD results of these subjects are
also presented for a quiet restful breathing rate, showing particle
tracks and structures in the flow field.
