Heated supersonic rectangular twin jets (SRTJ) with a total temperature ratio of 2, using nozzles of design Mach number 1.5 and aspect ratio 2, were investigated in flow regimes from overexpanded to the design condition (Mj = 1.3–1.5). This work complements our recently published work in unheated SRTJ using the same experimental facility (Samimy et al., J. Fluid Mech, vol. 959, 2023, A13). Localized arc filament plasma actuators (LAFPAs) were used to excite the natural instabilities in the jets, thereby controlling the flow and acoustics. The results show that the jets were coupled primarily out-of-phase in overexpanded cases, that the coupling had significant effects on the near-field (NF) pressure fluctuations, and that these fluctuations were considerably higher for in-phase than for out-of-phase coupled cases. The results also revealed that the far-field (FF) overall sound pressure level is significantly higher on the minor axis plane of the SRTJ and that the onset of Mach wave radiation contributes to the increased acoustic radiation at the peak noise direction. The LAFPAs successfully controlled the coupling and were able to reduce the NF pressure fluctuations by 10 dB. However, only 1 to 2 dB FF noise reduction at the peak noise radiation direction was achieved. The overall trends of the baseline results and response of the flow to excitation are qualitatively similar in unheated and heated cases, but the details are significantly different.

中文翻译：

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加热超音速矩形双射流中流量和近场压力脉动的主动控制

总温度比为 2 的加热超音速矩形双喷流 (SRTJ)，使用设计马赫数 1.5 和展弦比 2 的喷嘴，在从过度膨胀到设计条件的流态下进行了研究（中号j= 1.3–1.5）。这项工作补充了我们最近发表的使用相同实验设施（Sammy等人。,流体机械学报，卷。 959、2023、A13​​）。局部电弧灯丝等离子体致动器（LAFPA）用于激发射流中的自然不稳定性，从而控制流量和声学效果。结果表明，在过度膨胀的情况下，射流主要是异相耦合的，耦合对近场（NF）压力波动有显着影响，并且同相的这些波动比异相的波动要高得多。异相耦合情况。结果还表明，SRTJ 短轴平面上的远场 (FF) 总体声压级明显较高，并且马赫波辐射的出现导致峰值噪声方向的声辐射增加。 LAFPA 成功控制了耦合，并且能够将 NF 压力波动降低 10 dB。然而，在峰值噪声辐射方向仅实现了 1 至 2 dB FF 噪声降低。在未加热和加热情况下，基线结果的总体趋势和流动对激励的响应在质量上相似，但细节显着不同。