This paper concerns a study of pressure fluctuations beneath hypersonic shock- wave turbulent boundary layer interactions and the associated acoustic loading on a compression/expansion ramp. We have employed high-order implicit large eddy simulations and conducted simulations at Mach 7.2. The spectral analysis of the pressure fluctuations at various locations of the compression/expansion ramp are compared with the spectra calculated beneath a hypersonic transitional boundary layer. Similarities and differences between the two hypersonic boundary layers, in the context of acoustic loading, are drawn. Extremely high values of pressure fluctuations are recorded after the shock re-attachement where the maximum pressure gradients are also observed, indicating that acoustic loading is correlated with areas of high pressure gradients. Finally, we show the impact of the boundary layer state (attached flow, turbulence bursts, recirculations, shock oscillations, shock re-attachment and expansion fans) on the frequency spectrum of the pressure fluctuations.

中文翻译：

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高速过渡和湍流边界层下的计算气动声学

本文涉及对高超声速冲击波湍流边界层相互作用下的压力波动和压缩/膨胀斜坡上相关声学载荷的研究。我们采用了高阶隐式大涡模拟并以 7.2 马赫进行了模拟。压缩/膨胀斜坡不同位置的压力波动的频谱分析与在高超声速过渡边界层下计算的频谱进行了比较。在声学载荷的背景下，绘制了两个高超声速边界层之间的异同。在冲击重新附着后记录到极高的压力波动值，其中还观察到最大压力梯度，表明声载荷与高压梯度区域相关。最后，