V.G.Basovsky, I.V.Vovk, O.I.Vovk Peculiarities of oscillations of human trachea walls |
Acoustic bulletin, Vol. 4 ¹ 3, (2001) |
| The results of the analysis of peculiarities of trachea wall composition and discussion of the possible mechanisms of its excitation are presented. The acoustical and mathematical models of trachea with elastic walls are developed. These models foresee the possibilities of kinematic excitation of the upper end of the trachea and propagation of an elastic wave along the trachea wall. In the wide frequency range a quantitative analysis of modulus and phase of the oscillatory velocity of the trachea elastic wall is performed. These data are compared to those obtained for the acoustical model of trachea with locally responding walls. It is shown that the elastic wall behaves as a delay line, and an elastic wave can propagate along this line in the range of low frequencies (f<500 Hz), having the speed about 10-20 m/s. At higher frequencies the elastic wall behaves like a locally responding surface. It is shown that even relatively low levels of kinematic excitation of the upper end of trachea cause the significant changes in character of the frequency dependence of the trachea wall oscillatory velocity. The analysis of the frequency dependencies of oscillatory velocities of the first seven circular cartilages of the trachea wall is performed. It is discovered that their levels diminish with the increase of distance of a cartilage from the upper end of a trachea. The relatively simple technique allowing to estimate the real values of the transmission function of the oscillatory velocity from vocal chords to the upper end of the trachea is proposed. |
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KEY WORDS: trachea, the annular cartilage, locally-responsive surface vibration velocity |
| TEXT LANGUAGE: Russian |