Advanced Topics and Future Trends - Computational Fluid and Particle Dynamics in the Human Respiratory System - page 320

Fig. 9.5 Streamline plot and
contours of velocity along
vertical symmetry plane,
bottom wall and several axial
cross-sections for
P 20 Pa taken from

Rasani et al. (2011)

=

recirculation is observed immediately downstream of the elastic wall above the jet
streams. Streamlines from the upper and bottom half of the inlet reveals the tendency
for the stream to migrate towards the side walls, where the cross-sectional area is
more open. Thus, the swirling strength of the inner recirculation core is increased as
the outer streams follow the curvature of the walls.
As a further example of the research opportunities in using FSI for sleep apnea
applications, stability analysis using a 3D realistic model for palatal snoring is pre-
sented here. A detailed schematic of the upper airway including the nasal and oral
cavity separated by the soft palate in the pharyngeal area is shown in Fig. 9.6 . Both
nostrils and oral openings represent the inlet boundaries for the airway during in-
halation, while the downstream end of the trachea represents the outlet boundary.
The fluid domain is surrounded by rigid walls except at the soft palate which is the
elastic fluid-structural interface region. A coupled fluid dynamics solver with struc-
tural dynamics solver is applied with a time-dependent constant inhalation rate can
be applied to investigate the instability of the soft palate.
For the interested reader, additional examples of FSI in internal physiological
flows is presented in Heil and Hazel (2011) which provides a review of self-excited