Artificial saliva sprays are commonly used to remedy vocal folds surface hydration. Vocal folds surface hydration and its effect on their auto-oscillation are studied experimentally using artificial vocal folds. The airflow is used to excite the vocal folds into auto-oscillation after which the vocal folds surface is sprayed with a liquid. The validity of the findings described in a previous study [A. Bouvet, X. Pelorson, and A. Van Hirtum, “Influence of water spraying on an oscillating channel,” J. Fluids Struct. 93, 102840 (2020)] concerning the effect of water spraying is further investigated. First, artificial saliva sprays (up to 5 ml) are sprayed instead of water. It is shown that this allows us to address the effect of increased dynamic viscosity (up to 8 times compared to water) as other artificial saliva properties affecting air–liquid mixing and surface wettability remain similar to water. Second, the Reynolds number in the dry stage is systematically increased (with 60%) for constant spraying volume ≥3 ml. Regardless of the sprayed liquid and Reynolds number, oscillation cycles are characterized by an increase in mean upstream pressure, cycle-to-cycle variability, and a decrease in oscillation frequency due period doubling. Increasing the dynamic viscosity tends to reduce the magnitude of these tendencies for spraying volumes smaller than 3 ml, indicating that viscous liquid–gas mixing affects the flow regime. Systematic Reynolds number variation shows that liquid spraying increases the oscillation onset threshold pressure and that the magnitude of general tendencies is reduced. The assessed conditions and features are pertinent to human voice production after hydration with an artificial saliva spray burst.

中文翻译：

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气流驱动流固耦合的水基液体喷涂

人工唾液喷雾剂通常用于修复声带表面的水合作用。声带表面水合作用及其对自动振荡的影响使用人工声带进行实验研究。气流用于激发声带进入自动振荡，然后向声带表面喷洒液体。先前研究中描述的结果的有效性 [A. Bouvet, X. Pelorson 和 A. Van Hirtum，“喷水对振荡通道的影响”，J. Fluids Struct。93, 102840 (2020)]关于喷水效果的进一步研究。首先，喷洒人工唾液喷雾剂（最多 5 毫升），而不是喷洒水。结果表明，这使我们能够解决动态粘度增加（与水相比高达 8 倍）的影响，因为影响气液混合和表面润湿性的其他人工唾液特性仍然与水相似。其次，干燥阶段的雷诺数系统地增加（60%），恒定喷雾量≥3 ml。不管喷洒的液体和雷诺数如何，振荡周期的特征是平均上游压力增加、周期间可变性以及由于周期加倍而导致的振荡频率降低。对于小于 3 ml 的喷雾体积，增加动态粘度往往会降低这些趋势的幅度，表明粘性液气混合会影响流动状态。系统雷诺数变化表明，液体喷射增加了振荡起始阈值压力，并且总体趋势的幅度减小。评估的条件和特征与人工唾液喷雾爆裂后水合后的人声产生有关。