The Prediction of Jet Noise From CFD Data
The Prediction of Jet Noise From CFD Data
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根据 CFD 数据预测喷射噪声
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
S. Boluriaan
中科院分区：
文献类型：
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作者：
P. Morris;S. Boluriaan
本文介绍了一种基于双方程湍流模型的喷流噪声预测方法。噪声模型是基于线性化欧拉方程的声学模拟。连续性方程和动量方程中都包含等效源。平均流声干扰效应基于Lilley方程和线性化欧拉方程的高频和低频渐近解。这些解决方案的有效性范围进行了讨论。高亚音速不加热射流的预测和测量之间的比较。结果表明，合理的预测，可以在所有的观察者的角度，而无需求助于第二个源机制。所有观察到的噪声频谱上的影响可以解释为平均流声干扰效应。有人认为，传统的对流放大效应相对较弱。它们的存在取决于噪声源的两点统计模型的特定选择。然而，平均流声相互作用的影响，导致预测的行为相当于对流放大。它示出，这种放大不是由于相对于观察者的源运动：但是，它是由于辐射到相对于观察者运动的平均流中的声音。此外，有人认为，“自我”和“剪切”噪声不是单独的噪声机制：它们是与线性化欧拉方程的减少到一个单一的波动方程的数学构造。
This paper describes a methodology for the prediction of jet noise based on data from a two-equation turbulence model. The noise model is an acoustic analogy based on the linearized Euler equations. Equivalent sources are included in both the continuity and momentum equations. Mean flow acoustic interaction effects are based on high and low frequency asymptotic solutions to both Lilley’s equation as well as the linearized Euler equations. The range of validity of these solutions is discussed. Comparisons are made between predictions and measurements for a high subsonic unheated jet. It is shown that reasonable predictions can be made at all observer angles without recourse to a second source mechanism. All the observed effects on the noise spectrum can be explained by mean flow acoustic interaction effects. It is argued that traditional convective amplification effects are relatively weak. Their existence depends on the particular choice of model for the two-point statistics of the noise sources. However, mean flow acoustic interaction effects result in a predicted behavior equivalent to convective amplification. It is shown that this amplification is not due to the source motion relative to the observer: but, it is due to the sound radiating into a mean flow that is in motion relative to the observer. In addition, it is argued that “self” and “shear” noise are not separate noise mechanisms: they are mathematical constructs associated with the reduction of the linearized Euler equations to a single wave equation.