开口风洞声阵列测量的剪切层修正方法

开口风洞中的相位传声器阵列测量，必须进行剪切层修正才能得到真实的噪声源位置信息。在0.55m×0.40m声学风洞中开展了剪切层修正的实验研究，得到了不同风速条件下的剪切层速度剖面、声波传播延迟时间和声源定位的结果。根据实验结果，对剪切层速度剖面的Gortler理论解进行了验证，并对比分析了4种剪切层修正方法。研究结果表明:选择自相似参数σ=9，ξ₀=0.2时剪切层速度剖面测量值与理论值符合较好；剪切层厚度与轴向距离的关系为y=0.15x；马赫数Ma≤0.3、测量角θ_m在40°~140°范围内，不同剪切层修正方法对声波延迟时间计算结果的相对误差在1%以内。提出了射线追踪快速计算方法，该方法较常规射线追踪法的计算速度可提高2个数量级，从而使其适用于声阵列在线测量。

Shear layer correction methods for open-jet wind tunnel phased array test

To identify the true location of the noise sources, the shear layer effect must be taking into account when conducting the microphone array test in open-jet wind tunnels. An experimental study for the shear layer correction was performed in the 0.55m×0.40m aero-acoustic tunnel of China Aerodynamics Research and Development Center(CARDC). The shear layer velocity profiles, source-receiver delay times and source identification results were obtained. The Gortler's velocity-profile solution was validated and four different shear layer correction methods were compared and analyzed on the basis of the experimental results. The research results show that:the velocity-profile experimental data agrees well with calculations when the self-similar parameters σ=9, ξ₀=0.2 are chosen, and the relationship between the fitted shear layer thickness and the axial distance data can be presented by the equation y=0.15x; Ma ≤ 0.3 and the measurement angle θ_m within 40°~140°, the relative calculation error of the delay time of different shear layer correction methods is smaller than 1%; the accuracy of the other three methods are quite close to the Amiet 2D method. A fast ray tracing method that is 100 times faster than the conventional ray tracing method is proposed, which makes the ray tracing method applicable for on-line microphone array data processing.