The Sound of Flow Over Rigid Walls
The Sound of Flow Over Rigid Walls
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流过坚硬墙壁的声音
DOI：
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
Meng Wang
中科院分区：
文献类型：
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作者：
W. Devenport;Nathan Alexander;S. Glegg;Meng Wang
本文综述了低马赫数下粗糙表面和不连续表面上边界层流动的声学特性。粗糙度噪声主要是由非定常切向压力作用在不均匀表面产生的偶极子辐射引起的。压力波动可能是由上覆边界层的湍流或上游粗糙度特征的尾迹产生的，但无论哪种情况，声音都可以从壁面压力频谱和表面几何形状来预测。小的不连续，如台阶和间隙，是孤立的二维粗糙度的特殊情况。向前迈步子比向后迈步子声音大得多，因为向前迈步子在步子附近会产生强烈的湍流。间隙噪声主要由间隙的任何暴露的前向部分控制。舍入可以大大降低前向阶跃噪声，适度的扫频不会改变噪声的产生机制。
An overview of the acoustics of boundary layer flows over rough surfaces and surfaces with discontinuities at low Mach number is presented. Roughness noise is dominated by dipole radiation produced by unsteady tangential pressure forces on the uneven surface. Pressure fluctuations may be generated by turbulence of the overriding boundary layer or by the wakes of upstream roughness features, but in either case the sound can be predicted from the wall pressure frequency spectrum and the surface geometry. Small discontinuities, such as steps and gaps, are special cases of isolated two-dimensional roughness. Forward steps are much louder than backward steps because the former generate strong turbulence close to the step. Gap noise is dominated by any exposed forward-step portion of the gap. Rounding can substantially reduce forward step noise, and moderate sweep does not alter the noise-generation mechanism.