Fluid dynamics in airway bifurcations: III. Localized flow conditions

Localized flow conditions ( e.g., backflows) in transition regions between parent and daughter airways of bifurcations were investigated using a compu tational fluid dynamics software code ( FIDAP) with a Cray T90 supercompute r. The configurations of the bifurcations were based on Schreck's ( 1972) l aboratory models. The flow intensities and spatial regions of reversed moti on were simulated for different conditions. The effects of inlet velocity p rofiles, Reynolds numbers, and dimensions and orientations of airways were addressed. The computational results showed that backflow was increased for parabolic inlet conditions, larger Reynolds numbers, and larger daughter-t o-parent diameter ratios. This article is the third in a systematic series addressed in this issue; the first addressed primary velocity patterns and the second discussed secondary currents.