Generation of Computational Mesh for CFPD Simulations - Computational Fluid and Particle Dynamics in the Human Respiratory System - page 95

section being the respiratory airway. Furthermore, the body part of the humanoid
is simplified to a single block geometry to allow easier meshing. Because we are
not concerned with the outside flow, a detailed section of the legs and feet is not
necessary. However, if we were to study the effects of the humanoid torso on the
upwards flow towards the nostrils, then a more accurate model of the torso and legs
might need to be considered.
Head of the Humanoid in a Room The head of the humanoid is shown in Fig. 4.24 .
The geometry can be viewed as a shell casing with mesh elements filling the con-
ducting respiratory airway passage. In designing such a mesh, the user needs to
delineate the wall boundaries which act as a determinant of the enclosed space to be
meshed.
Fig. 4.24 Model of the humanoid head, showing that tetrahedral mesh elements are present on the
surface of the head. The dotted box is the nasal region that is re-shown in magnified form later in
Fig. 4.25
Nasal Cavity, Nasopharynx Figure 4.25 shows the position of the nasal cavity
geometry in relation to the head and face. The fine mesh near the walls and its
gradual growth factor outwards from the surfaces are evident. Note that the nostrils
are open casings to allow the contiguous passageway for the internal mesh elements.
Larynx, Trachea The larynx and trachea in Fig. 4.25 has similar meshing features to
the nasal cavity as expected because it is simply a connection to upstream geometries.
This region is closed at the oropharynx. This is typical of most reconstructed realistic
oropharynx-larynx-trachea airways since it relies on CT scanned images where the
patient usually has the mouth closed and the back of the tongue closes the oral
passageway (Fig. 4.26 ).