The airflow in a subject-specific breathing human lung is simulated with a
multiscale computational fluid dynamics (CFD) lung model. The three-dimensional
(3D) airway geometry beginning from the mouth to about 7 generations of airways
is reconstructed from the multi-detector row computed tomography (MDCT) image
at the total lung capacity (TLC). Along with the segmented lobe surfaces, we
can build an anatomically-consistent one-dimensional (1D) airway tree spanning
over more than 20 generations down to the terminal bronchioles, which is
specific to the CT resolved airways and lobes (J Biomech 43(11): 2159-2163,
2010). We then register two lung images at TLC and the functional residual
capacity (FRC) to specify subject-specific CFD flow boundary conditions and
deform the airway surface mesh for a breathing lung simulation (J Comput Phys
244:168-192, 2013). The 1D airway tree bridges the 3D CT-resolved airways and
the registration-derived regional ventilation in the lung parenchyma, thus a
multiscale model. Large eddy simulation (LES) is applied to simulate airflow in
a breathing lung (Phys Fluids 21:101901, 2009). In this fluid dynamics video,
we present the distributions of velocity, pressure, vortical structure, and
wall shear stress in a breathing lung model of a normal human subject with a
tidal volume of 500 ml and a period of 4.8 s. On exhalation, air streams from
child branches merge in the parent branch, inducing oscillatory jets and
elongated vortical tubes. On inhalation, the glottal constriction induces
turbulent laryngeal jet. The sites where high wall shear stress tends to occur
on the airway surface are identified for future investigation of
mechanotransduction.Comment: This submission is part of the APS DFD Gallery of Fluid Motio