A CFD Coupled Acoustics Approach for Coaxial Jet Noise
A CFD Coupled Acoustics Approach for Coaxial Jet Noise
复制标题
针对同轴射流噪声的 CFD 耦合声学方法
DOI：
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发表时间：
2003
期刊：
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通讯作者：
A. Bassetti
中科院分区：
文献类型：
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作者：
G. Page;J. McGuirc;Mamdud Hossain;R. Self;A. Bassetti
虽然预测喷气噪声的最一般方法是利用直接数值模拟或大涡模拟来模拟整个非定常流场，但这种方法在工程环境中是不可行的。提出了一种将标准雷诺平均Navier-Stokes CFD方法与基于Lighthill的同轴射流噪声模型相耦合的方法。这具有相对较低的计算资源要求，同时具有反映喷嘴几何形状的变化如何修改噪声谱的物理机制。利用单股射流噪声数据对噪声模型中的三个参数进行了标定，并将其应用于同轴射流噪声。共面共轴射流问题的diffiering面积和速度比与测量的噪声谱表现出合理的协议。然而，四分之三喷管构型与实验结果的一致性很差。在喷嘴上添加锯齿只会使RANS计算流体动力学模型预测的湍流强度和长度尺度发生微小变化，因此在频谱中只观察到微小变化-低频噪声减少，高频噪声增加。
Whilst the most general methodology to predict jet noise utilises Direct Numerical Simulation or Large Eddy Simulation to model the full unsteady ∞owfleld, such an approach is unfeasible in an engineering context. A method is proposed to couple a standard Reynolds Averaged Navier-Stokes CFD method with a Lighthill based noise model for coaxial jets. This has relatively low computational resource requirements, whilst possessing the physical mechanisms to re∞ect how changes in nozzle geometry modify the noise spectra. The three parameters in the noise model were calibrated using single stream jet noise data and then applied to coaxial jet ∞ows. Coplanar coaxial jet problems for difiering area and velocity ratios showed reasonable agreement with measured noise spectra. However, a three-quarter cowl nozzle conflguration showed poor agreement with experiment. Serrations added to the nozzle produced only small changes in the turbulence intensity and length scale predicted by the RANS CFD model and consequently only minor changes were observed in the spectra - a reduction in low frequency noise coupled with an increase at higher frequencies.