International Journal of Fluid Mechanics Research

ISSN for PRINT: 1064-2277

For Online Access

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2001, Volume28

Issue 3

150 pages

Issue price - $250.00

V. G. Basovsky
Institute of Hydromechanics of National Academy of Sciences of Ukraine, Kyiv, Ukraine

I. V. Vovk
Institute of Hydromechanics of National Academy of Sciences of Ukraine, Kyiv, Ukraine

O. I. Vovk
Institute of Hydromechanics of National Academy of Sciences of Ukraine, Kyiv, Ukraine

Following the solution algorithm of the problem concerned with propagation of the sound waves in a bronchial tree, developed in the previous paper, the acoustic properties of human bronchial tree are numerically investigated. In particular, the imaginary part of an entry impedance of a bronchial tree is demonstrated to have resonances and antiresonances following one after another. Considerable "peaks" of the real part of an impedance therewith are found on the antiresonance frequencies, while "falls" on the resonances. A comparison between designed and experimental values of an input impedance is conducted and their satisfactory coincidence is shown. Distribution of the sound energy flows in the bronchial tree is studied. It is shown that the energy in the sound propagation process damps rather quickly at the expense of losses in visco-elastic walls of pneumatic paths and re-radiation by walls of the energy in the surrounding biotissue. The essential dependence is proved for phase velocity of the sound inside a bronchial tree both from frequency, and from choice of the initial and the final points of the bronchial tree site, for which this velocity is estimated. It is demonstrated that this speed can be much below and above the sound speed in the free air environment. Possible delay factor of the sound signal at its passing from the onset of trachea's up to the thorax surface is estimated.

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