Measurement of a Flow in a Larynx Model with a Vocal Fold Vibrating at High Frequencies

在嗓音分析中，建立一个能准确预测一对声带周围气流振荡、分离和再附着的数学模型是非常重要的，因为气流直接影响嗓音的声源。我们已经提出了一个非定常的一维可分离再附着流动模型，并证实该模型可以准确地预测在低至4 Hz的频率下振动的缩颈通道内的压力分布。本研究制作了一个声带振动频率为100 Hz的喉模型，测量了通道内流动振动、分离和再附着的基本数据，通过对实测压力波的分析，发现在频率大于20 Hz时，压力波出现非定常效应，在50 ~ 80 Hz时，压力波的变化趋势不同，用本文提出的数学模型模拟的压力波，其结果与实测值吻合较好，说明了该数学模型的正确性和需要改进的地方可分离和可重附流动模型在频率低于趋势变化的情况下与实测波浪吻合较好，将实验结果与理论结果进行比较，我们发现趋势的变化可能发生，因为我们不能控制声带模型和通道表面之间的0.1 mm的差距，或者/并且有效流动宽度和声带周围的通道宽度之间的差可能太大。流动模型和流动显示方法有待进一步探讨。

It is very important in voice analyses to establish a mathematical model which can accurately predict a flow oscillating, separating and reattaching around a pair of vocal folds, because the flow affects directly sound source of voice. We already proposed an unsteady one-dimensional separable and reattachable flow model and confirmed that this model can accurately predict pressure distribution in a channel with a constriction oscillating at low frequencies up to 4 Hz.In this research a larynx model with a vocal fold vibrating at 100 Hz was made, fundamental data of the flow vibrating, separating and reattaching in the channel was measured, and the validity and the points to be modified of the mathematical model were discussed based on comparison between the measured and calculated results.It was found from the measured pressure waves that effect of unsteadiness appeared at frequencies higher than 20 Hz and that the trend of the waves changed from 50 to 80 Hz.The pressure waves simulated using the proposed separable and reattachable flow model were in good agreement with the measured waves at frequencies lower than the trend changed.As a result of comparison between the experimental and theoretical results, we found that the change in the trend might occur because we could not control the gap of 0.1 mm between the vocal fold model and the channel surface or/and the difference between the effective flow width and the channel width around the vocal fold might be too large. We must further discuss the flow model and the flow visualization method.