Aeroacoustic Sound Source Characterization of the Human Voice Production-Perturbed Convective Wave Equation
Aeroacoustic Sound Source Characterization of the Human Voice Production-Perturbed Convective Wave Equation
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DOI：
10.3390/app11062614
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发表时间：
2021-03-01
影响因子：
2.7
通讯作者：
Kaltenbacher, Manfred
中科院分区：
文献类型：
--
作者：
Schoder, Stefan;Maurerlehner, Paul;Kaltenbacher, Manfred
基于一个经过验证的语音模型，研究了人发声的流致声源。该分析是使用基于扰动对流波方程的混合航空声学工作流程进行的。在第一步中，验证的三维不可压缩湍流模拟计算的有限体积法使用STARCCM+。在第二步中，详细评估和研究了航空声源。的声源的制定相比，简化（忽略对流源）系统地使用时域和傅立叶空间分析。此外，使用有限元求解器openCFS求解波动方程，以获得声学远场的3D声场。在详细的效果分析中，远场声谱进行了定量比较，流致声源在喉内可视化。在这方面的贡献，它表明，对流部分的源占主导地位的局部附近的声带（VFs），而当地的时间导数的不可压缩的压力分布在整个声门上区域。虽然时间导数的最大振幅较低，但积分贡献占主导地位。作为详细的扰动对流波方程源研究的副产品，我们表明，对流源项可以忽略不计，因为它只减少了0.6%的验证误差。忽略对流部分降低了扰动对流波方程的气动声源计算的算法复杂度和存储的流动数据。从源可视化中，我们了解了VF运动如何转换为航空声源的特定特征。我们发现，如果VF是完全关闭，气动声源项产生最高的动态范围。如果VF没有完全关闭，VF运动不会像健康语音的情况那样向流致声源提供那么多的源能量。由于没有完全关闭VF，周期性脉动速度射流没有被完全切断，因此湍流结构永久存在于声门上区域内。这些湍流结构增加了语音信号的宽带分量，这支持了先前关于声门闭合和发声不足的研究结果。
The flow-induced sound sources of human voice production are investigated based on a validated voice model. This analysis is performed using a hybrid aeroacoustic workflow based on the perturbed convective wave equation. In the first step, the validated 3D incompressible turbulent flow simulation is computed by the finite volume method using STARCCM+. In a second step, the aeroacoustic sources are evaluated and studied in detail. The formulation of the sound sources is compared to the simplification (neglecting the convective sources) systematically using time-domain and Fourier-space analysis. Additionally, the wave equation is solved with the finite element solver openCFS to obtain the 3D sound field in the acoustic far-field. During the detailed effect analysis, the far-field sound spectra are compared quantitatively, and the flow-induced sound sources are visualized within the larynx. In this contribution, it is shown that the convective part of the sources dominates locally near the vocal folds (VFs) while the local time derivative of the incompressible pressure is distributed in the whole supra-glottal area. Although the maximum amplitude of the time derivative is lower, the integral contribution dominates the sound spectrum. As a by-product of the detailed perturbed convective wave equation source study, we show that the convective source term can be neglected since it only reduces the validation error by 0.6%. Neglecting the convective part reduces the algorithmic complexity of the aeroacoustic source computation of the perturbed convective wave equation and the stored flow data. From the source visualization, we learned how the VF motion transforms into specific characteristics of the aeroacoustic sources. We found that if the VFs are fully closing, the aeroacoustic source terms yield the highest dynamical range. If the VFs are not fully closing, VFs motion does not provide as much source energy to the flow-induced sound sources as in the case of a healthy voice. As a consequence of not fully closing VFs, the cyclic pulsating velocity jet is not cut off entirely and therefore turbulent structures are permanently present inside the supraglottal region. These turbulent structures increase the broadband component of the voice signal, which supports research results of previous studies regarding glottis closure and insufficient voice production.