The noise from large-scale coherent turbulent structures within jets remains the dominant source. For the purpose of developing future control systems for the large-scale noise source, we investigate the statistics between upstream and downstream radiating waves. We investigate two off-design supersonic jet flows with instability theory and associated noise radiation, large-eddy simulation (LES), and experiments. We compare the auto-correlation, cross-correlation, coherence, and other statistics predicted by aeroacoustic instability theory. As instability waves are closely connected with the formation of large-scale turbulent structures, they yield insight into large-scale noise statistics. We investigate two nozzles at two supersonic off-design conditions. The first is a biconic nozzle operating at an unheated condition, and the second is a NASA nozzle operating at a heated condition. We find that for these jets, the noise from instability waves is coherent between 0.40 to 0.70 at large-scale radiation frequencies between the downstream and upstream radiation directions.

射流内大规模相干湍流结构产生的噪声仍然是主要来源。为了开发针对大型噪声源的未来控制系统，我们研究了上游和下游辐射波之间的统计数据。我们用不稳定性理论和相关的噪声辐射，大涡流模拟（LES）和实验研究了两种非设计的超音速喷射流。我们比较了自相关，互相关，相干性和其他由航空声学不稳定性理论预测的统计数据。由于不稳定波与大规模湍流结构的形成紧密相关，因此它们可提供对大规模噪声统计数据的洞察力。我们在两个超音速偏离设计条件下研究了两个喷嘴。第一个是在非加热条件下运行的双锥形喷嘴，第二个是在加热条件下运行的NASA喷嘴。我们发现，对于这些射流，在下游辐射方向和上游辐射方向之间的大规模辐射频率下，来自不稳定波的噪声在0.40至0.70之间是相干的。