Kinematic irreversibility of oscillatory flow in expanding and contracting small airways

Gaku Tanaka, Masayoshi Ohgawara, Genri Inagaki, Makoto Hishida, Toshihiro Sera

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Computational fluid dynamics (CFD) simulation was carried out for an oscillatory flow in an expanding and contracting model of small airways, and the effects of airway geometry and rhythmic breathing motion on the kinematic irreversibility of oscillatory flow were revealed. A 3D realistic model of multi-branching small airways was reconstructed from X-ray CT images of a mouse, which were obtained by the high-resolution synchrotron radiation CT system of SPring-8. Airway diameters range from 360 μm in the primary branch to 55 μm in the distal branch. The airway model was expanded and contracted in a sinusoidal volume change with time such that the geometry remains self-similar throughout a period. The Fluent software package was used for calculation of the fluid particle trajectory in the airway model. The dispersion of the fluid particle was evaluated in terms of the variance of the marked minute particles in the axial direction. The results show that the axial dispersion is enhanced by the expanding and contracting motion of the airways. It was also found that the augmentation of steady streaming is responsible for enhanced dispersion of fluid particles.

Original languageEnglish
Pages (from-to)1873-1880
Number of pages8
JournalInternational Journal of Heat and Mass Transfer
Volume55
Issue number7-8
DOIs
Publication statusPublished - Mar 1 2012
Externally publishedYes

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Kinematics
kinematics
fluids
particle trajectories
breathing
computational fluid dynamics
geometry
Fluids
mice
synchrotron radiation
computer programs
Geometry
augmentation
Synchrotron radiation
high resolution
Software packages
Computational fluid dynamics
Trajectories
x rays
simulation

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes

Cite this

Kinematic irreversibility of oscillatory flow in expanding and contracting small airways. / Tanaka, Gaku; Ohgawara, Masayoshi; Inagaki, Genri; Hishida, Makoto; Sera, Toshihiro.

In: International Journal of Heat and Mass Transfer, Vol. 55, No. 7-8, 01.03.2012, p. 1873-1880.

Research output: Contribution to journalArticle

Tanaka, Gaku ; Ohgawara, Masayoshi ; Inagaki, Genri ; Hishida, Makoto ; Sera, Toshihiro. / Kinematic irreversibility of oscillatory flow in expanding and contracting small airways. In: International Journal of Heat and Mass Transfer. 2012 ; Vol. 55, No. 7-8. pp. 1873-1880.
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