Hybrid Reynolds-Averaged Navier-Stokes/Implicit Large Eddy Simulation (RANS/ILES) high-resolution method was applied to investigate synthetic jets influence on potential core length and noise level in supersonic underexpanded jet from converging–diverging nozzle. In this work, temperature and pressure of ambient air were as follows: P = 100 kPa, T = 300 K. Nozzle pressure ratio was NPR = 4 and total temperature at the nozzle inlet was T i n ∗ = 300 K . Investigation of the accuracy of simulation was carried out before the investigation of synthetic jet influence. Synthetic jets were simulated using approximate boundary condition. Synthetic jets were injected from eight rectangular slits inside nozzle with step of 45° in azimuthal direction. The long sides of the slits were oriented along the longitudinal axis of the nozzle. The amplitude and frequency range of synthetic jets were as follows: q = 50.200 m/s, f = 60.300 Hz. Simulation results showed that the application of synthetic jets noticeably reduces the potential core length. Reducing the potential core length by 24% was achieved on one of the considered operating modes. An explanation for the mechanism of the action of synthetic jets on mixing layer of main jet flow was proposed. Synthetic jets influence on overall sound pressure and narrowband noise was revealed in near and far field. Operating modes, which decrease screech level on several observation angles, were found.

中文翻译：

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RANS/ILES方法研究合成射流对非设计超音速射流噪声水平及其频谱特性的影响

混合雷诺平均纳维-斯托克斯/隐式大涡模拟 (RANS/ILES) 高分辨率方法用于研究合成射流对来自收敛-发散喷嘴的超音速欠膨胀射流的潜在核心长度和噪声水平的影响。在这项工作中，环境空气的温度和压力如下：P = 100 kPa，T = 300 K。喷嘴压力比为 NPR = 4，喷嘴入口处的总温度为 T in ∗ = 300 K。在研究合成射流影响之前，先对模拟的准确性进行了研究。使用近似边界条件模拟合成射流。合成射流从喷嘴内的八个矩形狭缝以 45° 的方位角步长喷射。狭缝的长边沿喷嘴的纵轴定向。合成射流的幅度和频率范围如下：q = 50.200 m/s，f = 60.300 Hz。模拟结果表明，合成射流的应用显着减少了潜在的核心长度。在所考虑的一种操作模式下，将潜在磁芯长度减少了 24%。提出了合成射流对主射流混合层作用机理的解释。在近场和远场中都揭示了合成射流对整体声压和窄带噪声的影响。发现了在几个观察角度降低尖叫声级别的操作模式。在所考虑的一种操作模式下，将潜在磁芯长度减少了 24%。提出了合成射流对主射流混合层作用机理的解释。在近场和远场中都揭示了合成射流对整体声压和窄带噪声的影响。发现了在几个观察角度降低尖叫声级别的操作模式。在所考虑的一种操作模式下，潜在的磁芯长度减少了 24%。提出了合成射流对主射流混合层作用机理的解释。在近场和远场中都揭示了合成射流对整体声压和窄带噪声的影响。发现了在几个观察角度降低尖叫声级别的操作模式。