Two dimensional pressure field was acquired at 10 kHz to study the post flutter oscillations of a thin elastic panel placed beneath a Mach 2.5 turbulent boundary layer. The panel was made of aluminum and is secured to the mounting fixture using a collection of rivets, which resulted in a boundary condition that was between both ideally clamped and pinned boundaries. Direct comparison of the mean and unsteady pressure fields were made for the panel executing post flutter oscillations and oscillations away from the flutter boundary. Whereas the mean pressure fields were largely similar during and away from post-flutter oscillations, the unsteady pressure fields showed a significant increase in the during post flutter oscillations. The spectral content of the pressure oscillations and panel oscillations revealed that the tonal aeroelastic frequency dominate the post flutter oscillations. This tonal frequency was determined to lie at the close vicinity of the (2,1) panel elastic mode. The r.m.s. panel deflection field during post flutter oscillations were also reconstructed from the unsteady pressure fields and the reconstructed panel deflection also corresponded to the (2,1) elastic mode.Further coherence and cross-correlation analyses provided insights into possible mechanisms that control the transition of the panel oscillations away from the flutter boundary. The analyses suggest that the transition away from the flutter boundary is possibly initiated by the decoherence of the organized pressure field during the post flutter region by the turbulent boundary layer.

中文翻译：

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执行后颤振振荡的弹性面板的二维压力场成像

在 10 kHz 下采集二维压力场，以研究放置在 2.5 马赫湍流边界层下方的薄弹性板的颤振后振动。该面板由铝制成，并使用一组铆钉固定到安装夹具上，从而产生介于理想夹紧边界和固定边界之间的边界条件。对执行后颤振振荡和远离颤振边界振荡的面板进行平均压力场和非稳态压力场的直接比较。虽然平均压力场在颤振后振荡期间和远离后颤振振荡期间基本相似，但非稳态压力场在颤振后振荡期间表现出显着增加。压力振荡和面板振荡的频谱内容表明，音调气动弹性频率在颤振后振荡中占主导地位。该音调频率被确定为位于 (2,1) 面板弹性模式附近。颤振后振荡期间的均方根面板偏转场也可以根据非稳态压力场重建，并且重建的面板偏转也对应于 (2,1) 弹性模式。进一步的相干性和互相关分析提供了对控制转变的可能机制的见解面板振荡远离颤振边界。分析表明，远离颤振边界的转变可能是由湍流边界层在颤振后区域期间组织的压力场的退相干引发的。