Aerodynamic noise from a poroelastic edge with implications for the silent flight of owls
Aerodynamic noise from a poroelastic edge with implications for the silent flight of owls
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DOI：
10.1017/jfm.2013.139
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发表时间：
2013-05-01
影响因子：
3.7
通讯作者：
Peake, N.
中科院分区：
文献类型：
--
作者：
Jaworski, Justin W.;Peake, N.
湍流涡流与半无限多孔弹性边缘的相互作用，检查相对于弹性和孔隙率的气动噪声产生的效率的影响。散射问题的解决，使用维纳-霍普夫技术，以确定所产生的气动噪声对板和流动特性，包括对特征流速U的依赖性的标度依赖。特别注意多孔刚性和不可渗透弹性板条件的极限情况。这些特殊情况下的渐近分析揭示了参数的限制，远场声功率的规模像U-6的多孔边缘，和一个新的有限范围内的U-7的行为被发现的弹性边缘，与众所周知的U-5的依赖刚性不可渗透的边缘相比。进一步的数值计算结果试图解决后缘噪声可能会减轻多孔性和灵活性，并寻求加深了解猫头鹰如何狩猎声隐身。
The interaction of a turbulent eddy with a semi-infinite poroelastic edge is examined with respect to the effects of both elasticity and porosity on the efficiency of aerodynamic noise generation. The scattering problem is solved using the Wiener-Hopf technique to identify the scaling dependence of the resulting aerodynamic noise on plate and flow properties, including the dependence on a characteristic flow velocity U. Special attention is paid to the limiting cases of porous-rigid and impermeable-elastic plate conditions. Asymptotic analysis of these special cases reveals parametric limits where the far-field acoustic power scales like U-6 for a porous edge, and a new finite range of U-7 behaviour is found for an elastic edge, to be compared with the well-known U-5 dependence for a rigid impermeable edge. Further numerical results attempt to address how trailing-edge noise may be mitigated by porosity and flexibility and seek to deepen the understanding of how owls hunt in acoustic stealth.