Fig 1.
Geometric models of pulmonary acinus.
(a) Human airway model. (b) Two generations of alveolar ducts within the pulmonary acinus and alveolar sac composed of 14-hedrons. (c) Cross-section of alveolar sac for healthy, NSIP, and IPF models.
Table 1.
Parameters for healthy, NSIP, and IPF models.
Fig 2.
A schematic diagram of FSI iteration loop.
FSI coupling package is developed in the Python language (the top level FSI iteration script is shown in the S3 File). FSI coupling package and solvers exchange data of displacement and force using MPI.
Fig 3.
Cross-section and open boundary surface of computational meshes for fluid domain and tissue domain.
(a) Healthy, (b) NSIP, and (c) IPF.
Table 2.
CFD and CSD mesh sizes.
Fig 4.
Model schematic showing boundary conditions and applied loads.
(a) Pulmonary acinus model boundary conditions. PA is pressure in the alveolar and is applied to the inner surface of the tissue. PIP is intrapleural pressure and is applied to the outer surface of the tissue. (b) Intrapleural pressure ranging from 0 (FRC) to -244 Pa (FRC+TV).
Fig 5.
Temporal variation in contour of pressure drop at T = 0.5 s, T = 1.0 s, T = 1.5 s, T = 2.0 s, T = 2.5 s, T = 3.0 s, T = 3.5 s.
(a) Healthy, (b) NSIP, and (c)IPF.
Fig 6.
Maximum pressure drop history for healthy, NSIP, and IPF models.
Fig 7.
Temporal variation in contour of wall displacement at T = 0.5 s, T = 1.0 s, T = 1.5 s.
(a) Healthy, (b) NSIP, and (c) IPF.
Fig 8.
Flow velocity contours and streamlines at peak inspiration.
(a) Healthy, (b) NSIP, and (c) IPF.
Fig 9.
Stress contours of tissue at peak inspiration.
(a) Healthy, (b) NSIP, and (c) IPF. (d) Stress over time at several positions.
Fig 10.
Comparison of mechanical characteristics of healthy, NSIP, and IPF models.
(a) Comparison of the flow rate history. (b) Comparison of the flow domain relative to the volume change history.
Fig 11.
Comparison of lung function characteristics for healthy, NSIP, and IPF models.
(a) Comparison of pressure-volume loops. (b) Comparison of flow-volume loops.
Fig 12.
Comparison of pulmonary acinus resistance for healthy, NSIP, and IPF models.