Elucidation of the flow regulating mechanism in an avian respiratory system by a combination of X-ray visualization and computational fluid dynamics with parallel computing

2017 Fiscal Year Final Research Report

• Project/Area Number: 26702012
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Partial Multi-year Fund
• Research Field: Biomedical engineering/Biomaterial science and engineering
• Research Institution: Nagoya Institute of Technology (2017); Saitama University (2014-2016)
• Principal Investigator: Masanori Nakamura 名古屋工業大学, 工学(系)研究科(研究院), 教授 (20448046)
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: 呼吸 / 数値流体解析 / 鳥類

Outline of Final Research Achievements

The present study aims to elucidate the mechanism to regulate flow in an avian lung. The X-ray visualization demonstrated the presence of a stenosis proximal to the first branch of the main trachea. The flow simulations using an anatomically realistic model of a bird lung revealed the stenosis caused acceleration of inflow by vena contracta. As a consequence, the inflow is mostly directed towards posterior air sacs during an inspiration period, corroborating the inspiratory aerodynamic valving hypothesis stated in the earlier studies. Flow simulation studies also demonstrated that thickening of the air sac wall induces a harmonic mismatch between the inflating and deflating behavior of the air sac and the intra-pleural pressure. This brings difficulties in expansion of air sacs to draw in airs during inspiration, suggesting that a phasic match between flow and the behavior of air sacs is important for the flow regulation in avian lungs.

Free Research Field

生体医工学