An analysis is made of the nonlinear interactions between flow in the subglottal vocal tract and glottis, sound waves in the subglottal system and a mechanical model of the vocal folds. The mean flow through the system is produced by a nominally steady contraction of the lungs, and mechanical experiments frequently involve a 'lung cavity' coupled to an experimental subglottal tube of arbitrary or ill-defined effective length L, on the basis that the actual value of L has little or no influence on excitation of the vocal folds. A simple, self-exciting single mass mathematical model of the vocal folds is used to investigate the sound generated within the subglottal domain and the unsteady volume flux from the glottis for experiments where it is required to suppress feedback of sound from the supraglottal vocal tract. In experiments where the assumed absorption of sound within the sponge-like interior of the lungs is small, the influence of changes in L can be very significant: when the subglottal tube behaves as an open-ended resonator (when L is as large as half the acoustic wavelength) there is predicted to be a mild increase in volume flux magnitude and a small change in waveform. However, the strong appearance of second harmonics of the acoustic field is predicted at intermediate lengths, when L is roughly one quarter of the acoustic wavelength. In cases of large lung damping, however, only modest changes in the volume flux are predicted to occur with variations in L.

中文翻译：

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声带和声门下系统力学模型中的流动-结构耦合分析

对声门下声道和声门中的流动、声门下系统中的声波和声带的机械模型之间的非线性相互作用进行了分析。通过系统的平均流量是由肺名义上的稳定收缩产生的，并且机械实验经常涉及一个“肺腔”，该“肺腔​​”与任意或不明确的有效长度 L 的实验声门下管相连，基于实际值L 对声带的兴奋影响很小或没有影响。一个简单的、自激的声带单质量数学模型用于研究声门下域内产生的声音和来自声门的不稳定音量通量，用于需要抑制来自声门上声道的声音反馈的实验。在假设肺部海绵状内部对声音的吸收很小的实验中，L 变化的影响可能非常显着：当声门下管表现为开放式谐振器时（当 L 大到一半时）声波波长）预计体积通量大小会轻微增加，波形会有小幅变化。然而，当 L 大约是声波波长的四分之一时，在中间长度预测声场二次谐波的强烈出现。然而，在大肺阻尼的情况下，随着 L 的变化，预计体积通量只会发生适度的变化。当声门下管表现为开放式谐振器时（当 L 大到声波波长的一半时），预计体积通量幅度会轻微增加，波形会有微小变化。然而，当 L 大约是声波波长的四分之一时，在中间长度预测声场二次谐波的强烈出现。然而，在大肺阻尼的情况下，随着 L 的变化，预计体积通量只会发生适度的变化。当声门下管表现为开放式谐振器时（当 L 大到声波波长的一半时），预计体积通量幅度会轻微增加，波形会有微小变化。然而，当 L 大约是声波波长的四分之一时，在中间长度预测声场二次谐波的强烈出现。然而，在大肺阻尼的情况下，随着 L 的变化，预计体积通量只会发生适度的变化。