论文标题
超音速射流中轴对称尖叫音调的复杂值的共振模型
A complex-valued resonance model for axisymmetric screech tones in supersonic jets
论文作者
论文摘要
我们对膨胀不足的超音速射流中A1和A2尖叫声的产生的共振机制进行建模。从\ cite {mancinelli2019screech}最近提出的共振模型开始，其中上游旅行波是一种中性稳定的引导喷气模式，我们在这里提出了一个更完整的基于线性的基于线性稳定性的模型。我们研究温度和剪切层厚度效应，并表明，为了准确描述实验数据，必须将剪切层厚度的效果纳入射流模型模型中。然后，我们提出了一种改进的共振模型，以进行尖叫的频率预测，其中下游和上游旅行波可能具有复杂的波数和频率。这种共振模型需要了解共振回路上游和下游位置的反射系数。我们探讨了反射系数对共振模型的影响，并提出了一种识别方法。复杂模型模型确定了在时间上放大谐振循环的频流参数空间的有限区域，这是恢复谐振的必要条件。该模型提供了对实验测量结果的改进描述。
We model the resonance mechanism underpinning generation of A1 and A2 screech tones in an under-expanded supersonic jet. Starting from the resonance model recently proposed by \cite{mancinelli2019screech}, where the upstream-travelling wave is a neutrally-stable guided jet mode, we here present a more complete linear-stability-based model for screech prediction. We study temperature and shear-layer thickness effects and show that, in order to accurately describe the experimental data, the effect of the finite thickness of the shear layer must be incorporated in the jet-dynamics model. We then present an improved resonance model for screech-frequency predictions in which both downstream- and upstream-travelling waves may have complex wavenumber and frequency. This resonance model requires knowledge of the reflection coefficients at the upstream and downstream locations of the resonance loop. We explore the effect of the reflection coefficients on the resonance model and propose an approach for their identification. The complex-mode model identifies limited regions of frequency-flow parameter space for which the resonance loop is amplified in time, a necessary condition for the resonance to be sustained. This model provides an improved description of the experimental measurements.
