The sound from mixing layers simulated with different ranges of turbulence scales
The sound from mixing layers simulated with different ranges of turbulence scales
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使用不同范围的湍流尺度模拟的混合层的声音
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
J. Freund
中科院分区：
文献类型：
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作者：
R. R. Kleinman;J. Freund
湍流尺度在自由剪切流中产生远场声的作用通过直接数值模拟的时间发展，马赫数0.9混合层进行了研究。从相同的初始条件开始，模拟了四种流动，但雷诺数变化了12倍。在动量厚度雷诺数Reδm ≥ 300以上，所有混合层辐射的声能超过我们能够计算的明显渐近高雷诺数值的85%。湍流能量和压力波数谱显示了预期的雷诺数依赖性;两个最高雷诺数模拟显示了最高波数处惯性范围和Kolmogorov缩放的证据。远场压力谱随波数的衰减比相应的近场谱快得多，对雷诺数的敏感性明显降低。低波数几乎占了所有辐射的声能。远场流向波数压力分布
The role of turbulence scales in generating far-field sound in free shear flows is studied via direct numerical simulations of temporally developing, Mach 0.9 mixing layers. Four flows were simulated, starting from the same initial conditions but with Reynolds numbers that varied by a factor of 12. Above momentum thickness Reynolds number Reδm≈300, all the mixing layers radiate over 85% of the acoustic energy of the apparently asymptotically high-Reynolds-number value that we are able to compute. Turbulence energy and pressure wavenumber spectra show the expected Reynolds number dependence; the two highest Reynolds number simulations show evidence of an inertial range and Kolmogorov scaling at the highest wavenumbers. Far-field pressure spectra all decay much more rapidly with wavenumber than the corresponding near-field spectra and show significantly less sensitivity to Reynolds number. Low wavenumbers account for nearly all of the radiated acoustic energy. Far-field streamwise wavenumber pressure spectr...