An advanced synthetic eddy method for the computation of aerofoil-turbulence interaction noise
An advanced synthetic eddy method for the computation of aerofoil-turbulence interaction noise
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DOI：
10.1016/j.jcp.2015.01.039
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发表时间：
2015-04
期刊：
影响因子：
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通讯作者：
J. Kim;S. Haeri
中科院分区：
文献类型：
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作者：
J. Kim;S. Haeri
本文提出了一种利用专门为三维气动声学模拟设计的流入边界条件来综合产生湍流的先进方法。所提出的方法几乎不受合成湍流可能产生的伪噪声的影响，从而可以从声源机制直接计算传播声波。本工作源于合成涡流法（SEM）的最新成果之一，该方法推导出一个定义良好的矢量势函数，该函数创建了一个无散度的速度场，具有正确的涡流对流速度，理论上可以抑制压力波动。本文对扫描电镜进行了大量的扩展，并对其进行了系统的优化，以建立一个基于von Kármán速度谱的真实湍流场。然后将优化后的扫描电镜与成熟的海绵层技术相结合，从上游边界将湍流涡流安静地注入该区域，从而产生足够干净的声场。本方法的主要优点是：a)产生真正的三维湍流；B)可以创建各种参数化方法来控制/表征随机分布的涡流；c)它的数值实现是有效的，因为湍流涡流应该通过的区域截面的大小可以调整和最小化。通过对翼型-湍流相互作用噪声的三维模拟，验证了所提扫描电镜的性能和可靠性。
This paper presents an advanced method to synthetically generate flow turbulence via an inflow boundary condition particularly designed for three-dimensional aeroacoustic simulations. The proposed method is virtually free of spurious noise that might arise from the synthetic turbulence, which enables a direct calculation of propagated sound waves from the source mechanism. The present work stemmed from one of the latest outcomes of synthetic eddy method (SEM) derived from a well-defined vector potential function creating a divergence-free velocity field with correct convection speeds of eddies, which in theory suppresses pressure fluctuations. In this paper, a substantial extension of the SEM is introduced and systematically optimised to create a realistic turbulence field based on von Kármán velocity spectra. The optimised SEM is then combined with a well-established sponge-layer technique to quietly inject the turbulent eddies into the domain from the upstream boundary, which results in a sufficiently clean acoustic field. Major advantages in the present approach are: a) that genuinely three-dimensional turbulence is generated; b) that various ways of parametrisation can be created to control/characterise the randomly distributed eddies; and, c) that its numerical implementation is efficient as the size of domain section through which the turbulent eddies should be passing can be adjusted and minimised. The performance and reliability of the proposed SEM are demonstrated by a three-dimensional simulation of aerofoil–turbulence interaction noise.