Twin Jet Effects on Noise of Round and Rectangular Jets: Experiment and Model
Twin Jet Effects on Noise of Round and Rectangular Jets: Experiment and Model
复制标题
双射流对圆形和矩形射流噪声的影响：实验和模型
DOI：
10.2514/6.2014-2890
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
Richard F. Bozak
中科院分区：
文献类型：
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作者：
Richard F. Bozak
NASA基础航空计划提出的许多亚音速和超音速飞机概念都有不对称的集成推进系统。这些推进系统排气的不对称性产生了不对称的声场。本研究中研究的不对称性来自双喷流和矩形喷嘴。每种效应都会产生不同的声场变化。建立了双喷流间距为2.6~5.6的圆形双喷流声场变化的经验模型，其中S为喷口直径上的中心距。该模型包括考虑双喷流间距、喷流静温比、飞行马赫数、频率和观察者角度(极角和方位角)影响的参数。然后将该模型应用于双喷管2：1和8：1展弦比喷管，以确定喷流展弦比对喷管的影响。对于圆形和矩形射流，与非相干地添加两个射流的假设相比，该模型的使用将所有频率、观察角和射流间距上的平均误差幅度降低了约0.5dB。
Many subsonic and supersonic aircraft concepts proposed by NASA’s Fundamental Aeronautics Program have asymmetric, integrated propulsion systems. The asymmetries in the exhaust of these propulsion systems create an asymmetric acoustic field. The asymmetries investigated in the current study are from twin jets and rectangular nozzles. Each effect produces its own variation of the acoustic field. An empirical model was developed to predict the acoustic field variation from round twin jets with twin jet spacing from 2.6 to 5.6, where s is the center-to-center spacing over the jet diameter. The model includes parameters to account for the effects of twin jet spacing, jet static temperature ratio, flight Mach number, frequency, and observer angle (both polar and azimuthal angles). The model was then applied to twin 2:1 and 8:1 aspect ratio nozzles to determine the impact of jet aspect ratio. For the round and rectangular jets, the use of the model reduces the average magnitude of the error over all frequencies, observation angles, and jet spacings by approximately 0.5dB when compared against the assumption of adding two jets incoherently.