Unsteady heat-flux measurements of second-mode instability waves in a hypersonic flat-plate boundary layer
Unsteady heat-flux measurements of second-mode instability waves in a hypersonic flat-plate boundary layer
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DOI：
10.1007/s00348-016-2214-9
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发表时间：
2016-08-01
影响因子：
2.4
通讯作者：
Rufer, Shann J.
中科院分区：
文献类型：
--
作者：
Kegerise, Michael A.;Rufer, Shann J.
在本文中，我们报告了原子层热电堆（ALTP）热通量传感器在高超声速平板边界层层流到湍流转变测量中的应用。平板模型的中心线装有 ALTP 传感器的流向阵列，并且平板模型暴露于一系列单位雷诺数的马赫 6 自由流中。在这里，我们观察到与平板表面上形成的层流边界层中的第二模式不稳定波相关的不稳定频带。这些不稳定波的测量频率、群速度、相速度和波长与文献中先前报道的数据一致。热通量时间序列及其 Morlet 小波变换揭示了第二模态不稳定波的波包性质。此外，还使用基于激光的辐射加热系统来测量风洞测试中使用的 ALTP 传感器的频率响应函数 (FRF)。这些测量用于评估传感器频响函数随时间的稳定性，并校正有限传感器带宽引起的任何衰减的光谱估计。
In this paper, we report on the application of the atomic layer thermopile (ALTP) heat-flux sensor to the measurement of laminar-to-turbulent transition in a hypersonic flat-plate boundary layer. The centerline of the flatplate model was instrumented with a streamwise array of ALTP sensors, and the flat-plate model was exposed to a Mach 6 freestream over a range of unit Reynolds numbers. Here, we observed an unstable band of frequencies that are associated with second-mode instability waves in the laminar boundary layer that forms on the flat-plate surface. The measured frequencies, group velocities, phase speeds, and wavelengths of these instability waves are consistent with data previously reported in the literature. Heat flux time series, and the Morlet wavelet transforms of them, revealed the wave-packet nature of the second-mode instability waves. In addition, a laser-based radiative heating system was used to measure the frequency response functions (FRF) of the ALTP sensors used in the wind tunnel test. These measurements were used to assess the stability of the sensor FRFs over time and to correct spectral estimates for any attenuation caused by the finite sensor bandwidth.