声带振动对浊咝擦音湍流声生成的影响。

文献信息

中文摘要

浊擦音涉及口腔内湍流噪声生成与声带振动之间复杂的空气动力学相互作用。本研究将齿龈擦音/s/的简化声道模型与双质量声带模型相结合，进行气动声学模拟，以探究声带振动和舌运动对擦音发声的影响。对可压缩Navier-Stokes方程进行求解，所用声道模型中舌从擦音构型动态下降至元音/u/构型。振动条件与非振动条件的比较显示，在相同声门下压条件下，声带振动使4 kHz以上的高频擦音噪声降低约5 dB。流场显示，在振动条件下牙齿周围的湍流速度脉动减弱，提示部分空气动力学能量被转移用于维持声带振荡。在舌下降过程中，振动条件下的声门气流率增加比非振动条件更为逐渐。因此，浊音条件下擦音噪声衰减更早，提示声带振动促进从擦音噪声向元音发声的更早过渡，可能有助于浊擦音中辅音-元音过渡更加平滑。

英文摘要

Voiced fricatives involve complex aerodynamic interactions between turbulent noise generation in the oral cavity and vocal fold vibration. In this study, aeroacoustic simulations combining a simplified vocal tract model of the alveolar fricative /s/ with a two-mass vocal fold model were conducted to investigate the effects of vocal fold vibration and tongue motion on fricative sound production. The compressible Navier-Stokes equations were solved for a vocal tract model with the tongue dynamically lowered from the fricative configuration to the vowel /u/ configuration. Comparisons between vibrating and non-vibrating conditions showed that vocal fold vibration reduced high-frequency fricative noise above 4 kHz by approximately 5 dB under identical subglottal pressure. Flow field revealed reduced turbulent velocity fluctuations around the teeth in the vibrating condition, indicating that part of the aerodynamic energy was transferred to sustaining vocal fold oscillation. During tongue lowering, the glottal airflow rate increased more gradually in the vibrating condition than in the non-vibrating condition. Consequently, the fricative noise decayed earlier in the voiced condition, suggesting that vocal fold vibration facilitates an earlier transition from fricative noise to vowel production, potentially contributing to smoother consonant-vowel transitions in voiced fricatives.