Large-eddy simulation of low-frequency unsteadiness in a turbulent shock-induced separation bubble
Large-eddy simulation of low-frequency unsteadiness in a turbulent shock-induced separation bubble
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DOI：
10.1007/s00162-009-0103-z
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发表时间：
2009-05
影响因子：
3.4
通讯作者：
E. Touber;N. Sandham
中科院分区：
文献类型：
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作者：
E. Touber;N. Sandham
几十年来，对激波/湍流边界层相互作用中观察到的低频不稳定性的需要一直推动着这一领域的研究。本文对撞击斜激波与马赫数为2.3的湍流边界层的相互作用进行了大涡模拟研究。与以往关于激波/湍流边界层相互作用的大涡模拟研究相反，我们使用了一种流入技术，它不在区域中引入任何具有能量意义的低频，从而避免了对激波/边界层相互作用系统的可能干扰。与以前的计算研究相比，大涡模拟的运行时间要长得多，这使得对低频进行傅里叶分析成为可能。在相互作用中发现的宽带和高能低频成分与实验结果很好地吻合。在此基础上，对平均流进行了线性稳定性分析，发现了一个平稳不稳定的整体模式。对长期大涡模拟数据进行了分析，发现壁面压力波动的相变与整体振型结构有关，这可能是观测到的低频运动的驱动机制。
The need for better understanding of the low-frequency unsteadiness observed in shock wave/turbulent boundary layer interactions has been driving research in this area for several decades. We present here a large-eddy simulation investigation of the interaction between an impinging oblique shock and a Mach 2.3 turbulent boundary layer. Contrary to past large-eddy simulation investigations on shock/turbulent boundary layer interactions, we have used an inflow technique which does not introduce any energetically significant low frequencies into the domain, hence avoiding possible interference with the shock/boundary layer interaction system. The large-eddy simulation has been run for much longer times than previous computational studies making a Fourier analysis of the low frequency possible. The broadband and energetic low-frequency component found in the interaction is in excellent agreement with the experimental findings. Furthermore, a linear stability analysis of the mean flow was performed and a stationary unstable global mode was found. The long-run large-eddy simulation data were analyzed and a phase change in the wall pressure fluctuations was related to the global-mode structure, leading to a possible driving mechanism for the observed low-frequency motions.