Noise Predictions for Chevron Nozzle Flows
Noise Predictions for Chevron Nozzle Flows
复制标题
V 形喷嘴流量的噪声预测
DOI：
10.2514/6.2006-2600
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发表时间：
2006
影响因子：
4.6
通讯作者：
A. Secundov
中科院分区：
文献类型：
--
作者：
S. Birch;D. Lyubimov;V. Maslov;A. Secundov
尽管 LES 方法最近取得了进展，但基于 RANS 的喷气噪声预测模型似乎是开发适用于 V 形喷嘴流或其他先进喷嘴设计的喷气噪声预测程序的唯一现实的近期方法。本文描述了这种模型在一系列 V 形喷嘴流动中的应用，并将模型预测与实验数据进行了比较。结果表明，人字形以两种重要方式影响流动。第一个影响是轴向涡流导致混合层的宽度非常快速地增加。实际上，这个过程导致湍流和平均流量之间的局部不平衡，湍流产生的减少以及峰值湍流水平的总体降低，从而有助于降低较低频率的噪声。第二个更复杂，似乎涉及轴向涡流和射流湍流之间的相互作用，导致该区域的更多高频噪声辐射到远场。这种新噪声源的强度似乎与轴向涡流的强度成比例。
In spite of recent advances in LES methods, RANS based jet noise prediction models appear to be the only realistic, near term, approach for the development of a jet noise prediction procedure that is applicable to chevron nozzle flows, or other advanced nozzle designs. The present paper describes the application of such a model to a series of chevron nozzle flows and the model predictions are compared with experimental data. It is shown that the chevr ons affect t he flow in two important ways. The f irst effect is that the axial vortices cause a very rapid increase in the width of the mixing layer. This process, in effect, leads to a local im balance between the turb ulence and the mean flow, a reduction i n the turbulence production, and an overall reduction in the peak turbulence level, thus contributing to a noise reduction at the lower frequencies. The second is more complex and appears to involve an interaction between the axial vortices and the jet tur bulence that causes more of the high frequency noise from this region to be radiated to the far field. The strength of this new noise source appears to scale with the strength of the axial vortices.