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arXiv 1909.06299physics.flu-dyn
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可压缩层流和紊流空腔流的解析分析

Resolvent analysis of compressible laminar and turbulent cavity flows

Yiyang Sun, Qiong Liu, Louis N. Cattafesta, Lawrence S. Ukeiley, Kunihiko Taira

摘要:

目前的工作表明,使用预解式分析,以获得物理见解的开放腔流。预解式分析确定了对谐波强迫的流量响应,给出了稳定的基本状态,根据响应和强迫模式以及放大增益。的响应和强迫模式揭示了与此放大过程相关的空间结构。在这项研究中,我们进行解析分析层流和湍流超过一个矩形空腔的长度与深度比$L/D=6$在自由流马赫数为$M_\infty=0.6$在展向周期设置。基于基态的主导不稳定性,在预解式分析中引入折扣参数,考察了有限时间窗内的谐波特性。我们首先揭示了基本的流动物理和解释的结果从层流在$Re_D = 502$。这些结果从层流扩展到一个更实际的空腔流动的例子在一个更高的雷诺数$Re_D = 10^4$。层流和湍流空腔流的响应模式和强迫模式的特征与层流分析的空间结构相似。我们进一步发现,在流动响应中的能量的大放大与高频率的湍流,而流动是更响应于低频激励的层流的情况下。这些研究结果从预解式分析提供了有价值的见解,流动控制研究方面的参数选择和放置的致动器和传感器。

英文摘要:

The present work demonstrates the use of resolvent analysis to obtain physical insights for open-cavity flows. Resolvent analysis identifies the flow response to harmonic forcing, given a steady base state, in terms of the response and forcing modes and the amplification gain. The response and forcing modes reveal the spatial structures associated with this amplification process. In this study, we perform resolvent analysis on both laminar and turbulent flows over a rectangular cavity with length-to-depth ratio of $L/D=6$ at a free stream Mach number of $M_\infty=0.6$ in a spanwise periodic setting. Based on the dominant instability of the base state, a discount parameter is introduced to resolvent analysis to examine the harmonic characteristics over a finite-time window. We first uncover the underlying flow physics and interpret findings from laminar flow at $Re_D = 502$. These findings from laminar flow are extended to a more practical cavity flow example at a much higher Reynolds number of $Re_D = 10^4$. The features of response and forcing modes from the laminar and turbulent cavity flows are similar to the spatial structures from the laminar analysis. We further find that the large amplification of energy in flow response is associated with high frequency for turbulent flow, while the flow is more responsive to low frequency excitation in the laminar case. These findings from resolvent analysis provide valuable insights for flow control studies with regard to parameter selection and placement of actuators and sensors.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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