运动声源的边界元声全息识别方法研究
Nearfield acoustic holography based on inverse boundary element method for moving sound source identification
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摘要: 提出了一种可实现任意形状的运动结构噪声源识别的声全息方法。通过结合移动框架技术与边界元声全息技术两种算法的特点,提出利用移动框架技术将存在多普勒效应的时域数据转换成边界元声全息所需的双平面全息数据,然后由边界元法声全息公式重构任意结构表面的声学信息,实现运动结构噪声源定位。该方法既具有移动框架技术处理运动问题的快速简便,又具有边界元方法可处理任意形状问题的特点。最后在半消声水池中,对运动速度为9.96 cm/s的带帽圆柱壳体进行了试验验证,结果表明:在低速条件下,该方法能够准确反演得到该结构的表面有功声强以及声压等声场信息,从而实现噪声源定位。由于条件有限,高速验证需进一步验证。Abstract: A method for realizing noise source identification of the arbitrary shaped moving structure is present. A theoretical model is established, which is a combination of moving frame acoustic holography (MFAH) and acoustic holography based on boundary element method (BEM-based NAH). MFAH can change time-domain data which existing Doppler effects into the dual plane holographic data which is needed in the BEM-based NAH. The surface acoustic information of an arbitrary structure is reconstructed by BEM-based NAH, which can be used for location of noise source. It not only has the MFAH's fast and easy characteristics for dealing with movement problem, but also has the BEM-based NAH characteristics of dealing with arbitrary shape. Finally, an experiment test was conducted by using a moving hooded cylindrical shell which speed is 9.96 cm/s as research object in the semi-anechoic pool. The results showed that: the method can accurately realize the inversion of the structure of the surface of active sound intensity and sound pressure and other information in sound field, thereby achieving noise source location. Because of the condition limited, high-speed verification is needed in the future.