Investigation on Unsteady Interaction Phenomena of Shock Waves and Turbulent Boundary Layers in Supersonic Internal Flows

对超音速冲压发动机隔震器和进气道内的超音速内部激波流动，即伪激波（PSW）现象进行了实验和数值研究。实验结果总结如下：(1)通过彩色影照片和管道壁面压力波动测量，研究了2马赫和4马赫psw的位置、内部结构和特性。结果表明，在均匀流动马赫数M∞= 2的情况下，方形管道内出现了几何对称的λ型PSW。当马赫数M∞= 4时，风道内出现x型PSW，出现向顶壁或底壁较大偏移的不对称流动。(2)当M_∞= 2时，由于PSW振荡引起的壁面压力大波动发生在PSW的第一次激波下，而当M_∞= 4时，壁面压力大波动发生在PSW的第一次和第二次激波下。(3)采用剪切敏感液晶技术对PSWs的壁面剪应力进行了定性显示，并采用自制剪应力传感器对其进行了定量测量。结果表明，在马赫数为4的情况下，顶壁面边界层分离区存在反向流动，分离的顶壁面边界层在顶壁面上重新附着，以及顶壁面剪应力大小在顶壁面内的变化规律。研究还发现，底部壁面边界层在PSW内广泛分离，分离区存在逆向流动。采用Harten-Yee二阶TVD格式和Baldwin-Lomax湍流模型进行了数值模拟。(4) 2马赫数PSW的计算结果与实验结果吻合较好。(5)在4马赫的PSW情况下，由于实验中的不对称特性，计算结果与实验结果存在一些差异，而这些差异在模拟中无法重现。然而，计算结果对于理解复杂的不对称现象是有价值的。少

Experimental and numerical investigations on the supersonic internal flows with shock waves, i.e., so called Pseudo-Shock Wave ( PSW) phenomena in rectangular ducts related to scramjet engine isolators and intakes, were conducted. Experimental results are summarized as follows:(1) The location, internal structure and characteristic of the Mach 2 and 4 PSWs were investigated by color shlieren photographs and duct wall pressure fluctuation measurements. As the results, it was revealed that in the case of uniform flow Mach number M∞= 2, λ-type PSW with symmetric geometry occurs in the square duct. In the case of Mach number M∞= 4, an X-type PSW occurs in the duct, and an asymmetric flow which deviates greatly to top or bottom wall appears.(2) In the case of M_∞= 2, large wall pressure fluctuations due to the PSW oscillations occur under the first shock wave of the PSW, while in the case of M_∞= 4, the large wall pressure fluctuations occur under the first and second shock waves of the PSW … More .(3) The wall shear stresses in PSWs were visualized qualitatively by shear-sensitive liquid crystal, and measured quantitatively by the hand made shear stress transducer. As the results, it was revealed that in the case of Mach 4 PSW reverse flows exist in the top wall boundary layer separation region, and that the separated boundary layer on the top wall is reattached, and how the magnitude of the wall shear stress change in the PSW. It was also revealed that the bottom wall boundary layer separates widely in the PSW and the reverse flow exist in the separation region.Numerical simulations were carried out using the Harten-Yee second order TVD scheme and the Baldwin-Lomax turbulence model. Numerical results are summarized as follows:(4) The computational results for the Mach 2 PSW are in good agreement with the experimental results.(5) In the case of Mach 4 PSW, the several differences were found between the computational results and experiments due to asymmetric characteristics in the experiment which could not be reproduced in the simulation. However, the computational results are valuable for understanding the complex asymmetric phenomena. Less