周方奇, 王显圣, 杨党国, 等. 跨声速空腔剪切层动态特征传播特性研究[J]. 实验流体力学, 2024, 38(1): 103-108. DOI: 10.11729/syltlx20230066
引用本文: 周方奇, 王显圣, 杨党国, 等. 跨声速空腔剪切层动态特征传播特性研究[J]. 实验流体力学, 2024, 38(1): 103-108. DOI: 10.11729/syltlx20230066
ZHOU F Q, WANG X S, YANG D G, et al. Propagation characteristics of dynamic feature in transonic cavity shear layer[J]. Journal of Experiments in Fluid Mechanics, 2024, 38(1): 103-108. DOI: 10.11729/syltlx20230066
Citation: ZHOU F Q, WANG X S, YANG D G, et al. Propagation characteristics of dynamic feature in transonic cavity shear layer[J]. Journal of Experiments in Fluid Mechanics, 2024, 38(1): 103-108. DOI: 10.11729/syltlx20230066

跨声速空腔剪切层动态特征传播特性研究

Propagation characteristics of dynamic feature in transonic cavity shear layer

  • 摘要: 开式空腔流动发生时,剪切层内旋涡运动与腔内前传声波相互作用,引发空腔自持振荡现象。针对长深比为7的开式空腔,采用脉动压力测试技术,在Ma = 0.9来流条件下开展腔内剪切层动态特征试验研究,通过频谱分析和互相关分析,揭示剪切层动态特征发展机制和模态噪声传播规律。结果表明:剪切层内单调增大的宽频噪声和类余弦分布的模态噪声相互叠加,使剪切层整体动态特征呈波浪上升发展;模态噪声逆流向上行传播,其速度同样呈类余弦分布,变化趋势与模态噪声幅值保持一致。结合Rossiter模态预估理论发现:同频率的上行模态声波与下行旋涡相互作用,产生了类驻波现象,导致模态噪声功率谱密度和传播速度沿流向周期性变化。

     

    Abstract: In the shear layer of the open cavity flow, the vortex interacts with the pre-transmission sound wave, causing self-sustaining oscillation. For a cavity model with a length-to-depth ratio of 7, the dynamic characteristics of the shear layer in the cavity were tested under the incoming flow condition of Mach number 0.9 by the pulsating pressure measurement technology, and the propagation law of the modal noise in the shear layer is revealed by the spectrum analysis and cross-correlation analysis. The results show that the superposition of the monotonically increasing broadband noise and cosine-like modal noise in the shear layer causes the wave-rise characteristics of the overall dynamic of the shear layer. The modal noise propagates in the reverse flow direction, its velocity is also cosine-like, and the change trend is consistent with the modal noise amplitude. Combined with the Rossiter mode estimation theory, it is revealed that the interaction between modal sound waves and vortices of the same frequency produces a standing wave-like phenomenon, resulting in periodic changes in the power spectrum density and propagation velocity of the modal noise along the flow direction.

     

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