Abstract The paper presents numerical investigations of square jets in a wide range of Reynolds numbers with varying inlet turbulence characteristics. The research focuses on flow characteristics depending on inflow turbulent length/time scales and excitation frequencies in case of excited jets. It is found that the parameters of inlet turbulence affect the solutions qualitatively when the Reynolds number is sufficiently low. In these cases the impact of varying the turbulent time scale is considerably larger than changing the turbulent length scale. It was also observed that at sufficiently high Reynolds numbers the jets become quite independent of the inlet turbulence characteristics. This confirms findings of Xu et al. (Phys. Fluids, 2013) concerning weak/strong dependence of the jet evolution on inflow conditions. In case of excited jets the excitation frequencies play an important role and influence the jet behaviour most strongly at lower values of the Reynolds number. For some forcing frequencies a bifurcation occurs at sufficiently large forcing amplitudes. This phenomenon turned out to be independent of the assumed length and time scales of the turbulent fluctuations, both in terms of robustness as well as amplitude.

中文翻译：

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通过入口条件控制自然和激发方射流的时空演化

摘要 本文介绍了具有不同入口湍流特性的大雷诺数范围内方形射流的数值研究。研究的重点是流动特性取决于流入湍流长度/时间尺度和激发射流情况下的激发频率。发现当雷诺数足够低时，入口湍流参数对解有定性影响。在这些情况下，改变湍流时间尺度的影响比改变湍流长度尺度大得多。还观察到，在足够高的雷诺数下，射流变得与入口湍流特性完全无关。这证实了 Xu 等人的发现。(Phys. Fluids, 2013) 关于射流演化对流入条件的弱/强依赖性。在激发射流的情况下，激发频率起着重要作用，并且在雷诺数较低时对射流行为的影响最大。对于某些强迫频率，分叉发生在足够大的强迫幅度处。事实证明，这种现象与假设的湍流波动的长度和时间尺度无关，无论是在稳健性还是幅度方面。