Bodaghi Dariush, Xue Qian, Zheng Xudong, Thomson Scott
Department of Mechanical Engineering, University of Maine, Orono, ME 04473, USA.
Department of Mechanical Engineering, Brigham Young University, Provo, UT 84602, USA.
Appl Sci (Basel). 2021 Feb;11(3). doi: 10.3390/app11031221. Epub 2021 Jan 29.
An in-house 3D fluid-structure-acoustic interaction numerical solver was employed to investigate the effect of subglottic stenosis (SGS) on dynamics of glottal flow, vocal fold vibration and acoustics during voice production. The investigation focused on two SGS properties, including severity defined as the percentage of area reduction and location. The results show that SGS affects voice production only when its severity is beyond a threshold, which is at 75% for the glottal flow rate and acoustics, and at 90% for the vocal fold vibrations. Beyond the threshold, the flow rate, vocal fold vibration amplitude and vocal efficiency decrease rapidly with SGS severity, while the skewness quotient, vibration frequency, signal-to-noise ratio and vocal intensity decrease slightly, and the open quotient increases slightly. Changing the location of SGS shows no effect on the dynamics. Further analysis reveals that the effect of SGS on the dynamics is primarily due to its effect on the flow resistance in the entire airway, which is found to be related to the area ratio of glottis to SGS. Below the SGS severity of 75%, which corresponds to an area ratio of glottis to SGS of 0.1, changing the SGS severity only causes very small changes in the area ratio; therefore, its effect on the flow resistance and dynamics is very small. Beyond the SGS severity of 75%, increasing the SGS severity, leads to rapid increases of the area ratio, resulting in rapid changes in the flow resistance and dynamics.
采用内部开发的三维流固声相互作用数值求解器，研究声门下狭窄（SGS）对发声过程中声门气流动力学、声带振动和声学的影响。该研究聚焦于SGS的两个特性，包括定义为面积减少百分比的严重程度和位置。结果表明，只有当SGS的严重程度超过阈值时才会影响发声，对于声门气流速率和声学而言，该阈值为75%，对于声带振动而言为90%。超过阈值后，随着SGS严重程度增加，气流速率、声带振动幅度和发声效率迅速下降，而偏度商、振动频率、信噪比和发声强度略有下降，开放商略有增加。改变SGS的位置对动力学没有影响。进一步分析表明，SGS对动力学的影响主要是由于其对整个气道流动阻力的影响，发现这与声门与SGS的面积比有关。在SGS严重程度低于75%（对应声门与SGS的面积比为0.1）时，改变SGS严重程度只会导致面积比发生非常小的变化；因此，其对流动阻力和动力学的影响非常小。超过SGS严重程度75%后，增加SGS严重程度会导致面积比迅速增加，从而导致流动阻力和动力学迅速变化。
