Flow and noise predictions for the tandem cylinder aeroacoustic benchmarka)
Flow and noise predictions for the tandem cylinder aeroacoustic benchmarka)
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DOI：
10.1063/1.3685102
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发表时间：
2012-03
影响因子：
4.6
通讯作者：
G. Brès;D. Freed;M. Wessels;S. Noelting;F. Pérot
中科院分区：
文献类型：
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作者：
G. Brès;D. Freed;M. Wessels;S. Noelting;F. Pérot
采用格子玻尔兹曼和Ffowcs - williams - hawkins方法对串联式气缸基准进行了流动和噪声预测。数值结果与美国宇航局兰利研究中心的基本气动研究隧道和安静流动设施（QFF）的实验测量结果进行了比较。本文主要研究了两种配置：第一种配置对应于具有均匀入流和展向周期边界条件的典型配置。为了研究安装效果，第二种配置与QFF的设置和几何形状相匹配，包括矩形开放式喷嘴和安装在跨度中的两个垂直侧板，以支持测试模型。在这两种模拟中，模拟了16个圆柱体直径的全跨度，与实验尺寸相匹配。总体而言，与实验表面数据、流场和辐射噪声测量结果吻合良好。特别是，侧板的存在显著地减少了在周期性边界条件下观察到的过度展向相干性，并改善了远场噪声谱中音调峰值幅度的预测。在辐射噪声的计算中加入侧板的贡献表明，预测光谱和指向性总体上有所增加，从而与实验测量结果更好地匹配。在主脱落频率和谐波处测量到的增加约为1 ~ 2db，这可能是由跨向侧板上的反射引起的。宽带电平也略高约2至3db，可能是由于喷嘴出口的剪切层撞击侧板。
Flow and noise predictions for the tandem cylinder benchmark are performed using lattice Boltzmann and Ffowcs Williams–Hawkings methods. The numerical results are compared to experimental measurements from the Basic Aerodynamic Research Tunnel and Quiet Flow Facility (QFF) at NASA Langley Research Center. The present study focuses on two configurations: the first configuration corresponds to the typical setup with uniform inflow and spanwise periodic boundary condition. To investigate installation effects, the second configuration matches the QFF setup and geometry, including the rectangular open jet nozzle, and the two vertical side plates mounted in the span to support the test models. For both simulations, the full span of 16 cylinder diameters is simulated, matching the experimental dimensions. Overall, good agreement is obtained with the experimental surface data, flow field, and radiated noise measurements. In particular, the presence of the side plates significantly reduces the excessive spanwise coherence observed with periodic boundary conditions and improves the predictions of the tonal peak amplitude in the far-field noise spectra. Inclusion of the contributions from the side plates in the calculation of the radiated noise shows an overall increase in the predicted spectra and directivity, leading to a better match with the experimental measurements. The measured increase is about 1 to 2 dB at the main shedding frequency and harmonics, and is likely caused by reflections on the spanwise side plates. The broadband levels are also slightly higher by about 2 to 3 dB, likely due to the shear layers from the nozzle exit impacting the side plates.