Streaming Caused by Oscillatory Flow in Peripheral Airways of Human Lung

Bing  Han; Hiroyuki  Hirahara; Sho  Yoshizaki

doi:10.4236/ojfd.2016.63019

Bing Han, Hiroyuki Hirahara, Sho Yoshizaki

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.

Keywords: Oscillatory Flow, Steady Streaming, HFOV, Bronchioles, Womersley Number

Cite this paper: Han, B. , Hirahara, H. and Yoshizaki, S. (2016) Streaming Caused by Oscillatory Flow in Peripheral Airways of Human Lung. Open Journal of Fluid Dynamics, 6, 242-261. doi: 10.4236/ojfd.2016.63019.

References

[1] Padmanabham, N. and Pedley, T.J. (1987) Three-Dimensional Steady Streaming in a Uniform Tube with an Oscillating Elliptical Cross-Section. Journal of Fluid Mechanics, 178, 325-343.
http://dx.doi.org/10.1017/S0022112087001241

[2] Lighthill, M.J. (1991) Biomechanics of Hearing Sensitivity. Journal of Vibration and Acoustics, 113, 1-13.
http://dx.doi.org/10.1115/1.2930149

[3] Leibovich, S. (1983) The Form and Dynamics of Langmuir Circulations. Annual Review of Fluid Mechanics, 15, 391-427.
http://dx.doi.org/10.1146/annurev.fl.15.010183.002135

[4] Lyne, W.H. (1971) Unsteady Viscous Flow in a Curved Pipe. Journal of Fluid Mechanics, 45, 13-31.
http://dx.doi.org/10.1017/S0022112071002970

[5] Hall, P. (1974) Unsteady Viscous Flow in a Pipe of Slowly Varying Cross-Section. Journal of Fluid Mechanics, 64, 209-226.
http://dx.doi.org/10.1017/S0022112074002369

[6] Haselton, F.R. and Scherer, P.W. (1982) Flow Visualization of Steady Streaming in Oscillatory Flow through a Bifurcating Tube. Journal of Fluid Mechanics, 123, 315-333.
http://dx.doi.org/10.1017/S0022112082003085

[7] Eckmann, D.M. and Grotberg, J.B. (1988) Oscillatory Flow and Mass Transport in a Curved Tube. Journal of Fluid Mechanics, 188, 509-527.
http://dx.doi.org/10.1017/S0022112088000825

[8] Fresconi, F.E., Wexler, A.S. and Prasad, A.K. (2008) Transport Profiles in the Conducting Airways of the Human Lung. International Journal of Heat and Mass Transfer, 51, 5552-5561.
http://dx.doi.org/10.1016/j.ijheatmasstransfer.2008.04.014

[9] Gaver, D.P. and Grotberg, J.B. (1986) An Experimental Investigation of Oscillating Flow in a Tapered Channel. Journal of Fluid Mechanics, 172, 47-61.
http://dx.doi.org/10.1017/S0022112086001647

[10] Goldberg, I.S., Zhang, Z. and Tran, M. (1999) Steady Streaming of Fluid in the Entrance Region of a Tube during Oscillatory Flow. Physics of Fluids, 11, 2957-2962.
http://dx.doi.org/10.1063/1.870154

[11] Weibel, E.R. (1963) Morphometry of the Human Lung. Springer Verlag and Academic Press, New York.
http://dx.doi.org/10.1007/978-3-642-87553-3