激波/湍流边界层干扰分离泡直接数值模拟  

Direct numerical simulation of separation bubble in shock wave/turbulent boundary layer interaction

作　　者：童福林[1,2,3] 董思卫 段俊亦 李新亮 TONG Fulin;DONG Siwei;DUAN Junyi;LI Xinliang(State Key Laboratory of Aerodynamics,China Aerodynamics Research and Development Center.Mianyang 621000,China;State Key Laboratory of High Temperature Gas Dynamics,Institute of Mechanics,Chinese Academy of Sciences,Beiing 100190,China;Computational Aerodynamics Institute,China Aerodynamics Research and Development Center,Mianyang 621000,China;School of Engineering Science,University of Chinese Academy of Sciences,Beiing 100049,China)

机构地区：[1]中国空气动力研究与发展中心空气动力学国家重点实验室,绵阳621000 [2]中国科学院力学研究所高温气体动力学国家重点实验室,北京100190 [3]中国空气动力研究与发展中心计算空气动力研究所,绵阳621000 [4]中国科学院大学工程科学学院,北京100049

出　　处：《航空学报》2022年第7期130-144,共15页Acta Aeronautica et Astronautica Sinica

基　　金：国家自然科学基金(11972356,91852203);国家重点研发计划(2019YFA0405300)。

摘　　要：采用直接数值模拟(DNS)方法对来流马赫数为2.25、33.2°激波角的入射激波/平板湍流边界层干扰分离泡进行了数值研究。在验证了计算结果可靠性的基础上,通过分析比较3个不同展向站位分离泡的非定常运动特性、分离微团几何特征和相干结构等,定量考察了三维展向结构差异的影响规律。研究发现,分离泡存在复杂的三维结构,其流向长度明显大于法向高度和展向宽度,整体上沿展向呈现中间高两边低的扁平型单峰结构。分离泡面积脉动预乘功率谱结果表明,分离泡的非定常运动表征为大尺度低频膨胀/收缩过程,其展向三维结构对峰值频率的影响较小,且分离泡两侧略滞后于中间。采用经验模态分解(EMD)方法对分离泡低频膨胀/收缩过程进行了条件统计分析。统计结果表明,膨胀和收缩运动对分离微团几何特征没有实质影响,各展向站位分离微团高度/长度比值的概率峰值出现在0.1附近,同时分离微团面积和法向高度近似满足二次方分布。此外,流向速度脉动场的本征正交分解(POD)分析指出,分离泡的非定常运动与低阶模态密切相关,而高阶模态的贡献相对较小。采用前10个低阶模态可以准确重构出分离泡的低频膨胀/收缩过程。Characteristics of separation bubbles in the interaction of a supersonic turbulent boundary layer at Mach number 2.25 with an impinging shock wave of 33.2° are investigated by means of Direct Numerical Simulation(DNS). After verifying the reliability of the numerical results, fundamental mechanisms associated with separation bubbles, including unsteadiness, separation micro-clusters geometries features and coherent structures, at three different spanwise locations are quantitatively compared to analyze the influence of the three-dimensionality in the spanwise direction. It is found that the separation bubble is highly three-dimensional, with the streamwise extent significantly larger than the wall-normal height and spanwise width. In the spanwise direction, the bubble height is generally large in the middle and small on both sides, exhibiting a single flat peak behavior. The pre-multiplied power spectrum density of the fluctuating separation bubble area suggests that the separation bubble unsteadiness is characterized by large-scale low-frequency contraction and dilation, which is less affected by the spanwise three-dimensionality. The bubbles on both sides lag slightly behind that in the middle. Conditional analysis based on Empirical Mode Decomposition(EMD) is performed to analyze the influence of the bubble dilation and contraction on geometries features of the separation micro-clusters. The statistical results indicate no essential changes in both motions, where the probability peak of the aspect ratio appears around 0.1, and the area and the normal height of the micro-clusters approximately satisfy the quadratic distribution. In addition, the Proper Orthogonal Decomposition(POD) analysis of the fluctuating streamwise velocity indicates that the unsteady motion of the separation bubble is strongly related to the low-order modes, whereas the contribution from the high-order modes is rather small. With the first ten low-order modes, the low-frequency dilation and contraction process of separation bubbles is ac

关 键 词：激波/湍流边界层干扰 分离泡 低频膨胀/收缩 经验模态分解 本征正交分解 

分 类 号：V211.3[航空宇航科学与技术—航空宇航推进理论与工程] O241.3[理学—计算数学]