TITLE:
Streaming Caused by Oscillatory Flow in Peripheral Airways of Human Lung
AUTHORS:
Bing Han, Hiroyuki Hirahara, Sho Yoshizaki
KEYWORDS:
Oscillatory Flow, Steady Streaming, HFOV, Bronchioles, Womersley Number
JOURNAL NAME:
Open Journal of Fluid Dynamics,
Vol.6 No.3,
September
22,
2016
ABSTRACT: Oscillatory flow facilitates gas exchange in human respiration system. In the present
study, both numerical calculation and PIV (Particle Image Velocimetry) measurement
indicate that, under the application of HFOV (High Frequency Oscillatory
Ventilation), apparent steady streaming is caused and augmented in distal airways by
the continuous oscillation, i.e., the core air moves downwards and the peripheral air
evacuates upwards within bronchioles. The net flow of steady streaming serves to
overcome the lack of tidal volume in HFOV and delivers fresh air into deeper lung
region. Also, numerical calculations reveal that the intensity of steady streaming is
mainly influenced by the geometry of airways with provided oscillatory frequency
and tidal volume, and it rises with Re and Wo up to a Re of about 124 and Wo of
about 5. Steady streaming is considered as an important factor for the ventilation efficiency
of HFOV.