Effect of Acoustic Excitation Amplitude on Airfoil Boundary Layer and Wake Development
Effect of Acoustic Excitation Amplitude on Airfoil Boundary Layer and Wake Development
复制标题
声激励幅度对翼型边界层和尾流发展的影响
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
J. Kawall
中科院分区：
文献类型：
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作者：
S. Yarusevych;P. Sullivan;J. Kawall
在低雷诺数条件下，实验研究了声激励幅值对NACA 0025翼型边界层和尾迹发展的影响。用热线风速仪、表面压力测量和流动显示对流动特性进行了研究。层流边界层分离发生在翼型的上表面，形成了分离的剪切层，在所有情况下都是如此。当流动以与分离剪切层中最大放大扰动的频率匹配的频率被激励时，自然剪切层扰动锁定在激励频率上，并促进转折。在分离的剪切层不能重新附着的情况下，激励幅度的增加超过最小阈值，最终导致剪切层重新附着
The effect of acoustic excitation amplitude on boundary layer and wake development for a NACA 0025 airfoil was studied experimentally at low Reynolds numbers. Flow characteristics were investigated with hot-wire anemometry, surface pressure measurements, and flow visualization. A laminar boundary layer separation occurs on the upper surface of the airfoil, forming a separated shear layer, for all situations examined. When the flow is excited at the frequency matching the frequency of the most amplified disturbance in the separated shear layer, natural shear layer disturbances lock onto the excitation frequency and transition is promoted. In the case when the separated shear layer fails to reattach, an increase of the excitation amplitude above a minimum threshold eventually results in shear layer reattachment