Modeling the bifurcating flow in an asymmetric human lung airway

Yang Liu, R. M.C. So, C. H. Zhang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

81 Citations (Scopus)


In a former paper, the inspiratory flow characteristics in a three-generation symmetric bifurcation airway have been numerically investigated using a control volume method to solve the fully three-dimensional laminar Navier-Stokes equations. The present paper extends the work to deal with asymmetric airway extracted from the 5th-11th branches of the model of Weibel (Morphometry of the Human Lung. New York Academic Press, Verlag, 1963) in order to more appropriately model human air passage. Computations are carried out in the Reynolds number range 200-1600, corresponding to mouth-air breathing rates ranging from 0.27 to 2.16l/s, representative for an averaged height man breathing from quiet to vigorous state. Particular attentions are paid to establishing relations between the Reynolds number and the overall flow characteristics, including flow patterns and pressure drop. The study shows that the ratios of airflow rate through the medial branches to that of their mother branches are the same, and this is also true for the ratios of airflow rate through the lateral branches. This partially explains why regular human breathing is not affected by airways of different sizes.
Original languageEnglish
Pages (from-to)951-959
Number of pages9
JournalJournal of Biomechanics
Issue number7
Publication statusPublished - 1 Jul 2003


  • Asymmetric bifurcation flow
  • Human lung
  • Three-dimensional modeling

ASJC Scopus subject areas

  • Biophysics
  • Orthopedics and Sports Medicine
  • Biomedical Engineering
  • Rehabilitation


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