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The combined effects of non‐planarity and asymmetry on primary and secondary flows in the small bronchial tubes
Author(s) -
Soni B.,
Lindley C.,
Thompson D.
Publication year - 2008
Publication title -
international journal for numerical methods in fluids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 112
eISSN - 1097-0363
pISSN - 0271-2091
DOI - 10.1002/fld.1802
Subject(s) - planar , planarity testing , vortex , secondary flow , laminar flow , reynolds number , asymmetry , mechanics , flow (mathematics) , geometry , physics , mathematics , turbulence , computer science , combinatorics , computer graphics (images) , quantum mechanics
The laminar flow in the small bronchial tubes is quite complex due to the presence of vortex‐dominated, secondary flows. In this paper, we report the results of a numerical investigation of the simultaneous effects of asymmetric and non‐planar branching on the primary and secondary flows in the small bronchial tubes, i.e. generations 6–12. We simulate steady‐state inspiratory flow at a Reynolds number of 1000 in three‐generation, asymmetric planar and non‐planar bronchial tube models. The non‐planar model was defined by applying a 90° out‐of‐plane rotation to the third‐generation branches. A detailed mesh refinement study was performed in order to demonstrate mesh independence. Significant differences were observed between flows in the planar and non‐planar models. An uneven mass flow distribution was observed in the non‐planar model in contrast to the evenly distributed mass flow in the planar model. The secondary flows created symmetric vortex patterns in the planar model, whereas vortex symmetry was lost in the non‐planar model. These results illustrate the importance of incorporating asymmetry in addition to non‐planarity in the geometric models. Copyright © 2008 John Wiley & Sons, Ltd.