非自由声场中目标声场还原与重建的等效源方法

为消除在非自由声场中重建声场时干扰声源对重建效果的影响,提出一种采用单个测量面上的声压和质点振速作为输入、等效源法作为分离和重建算法的非自由声场中目标声场还原与重建方法。该方法首先利用单面声压-质点振速测量和基于等效源法的声场分离技术将测量的混合声场分离为来自目标声源的向外传播的声场和来自干扰声源的向内传播的声场,然后利用向内传播的声场和目标声源的边界条件计算出干扰声在目标声源表面产生的散射声场,并将其从向外传播的声场中去除,还原出目标声源在自由声场条件下的辐射声场,最后利用还原的声场实现目标声场重建。通过数值仿真和实验检验了该方法的有效性和必要性。仿真和实验的结果表明,该方法可以在非自由声场的测量条件下,有效地去除干扰声的影响,实现目标声场的准确重建。 

An equivalent source method for recovering and reconstructing the target sound field in a non-free field

In a non-free field, the existence of disturbing sources would destroy the free-field condition required by near- field acoustic holography, and confuse the identification of target source due to the scattering effect caused by disturbing sound falling on the target source. To totally remove the influence of disturbing source, a method for recovering and reconstructing the target sound field in a non-free field was proposed based on the equivalent source method and the pressure-velocity measurement. In the proposed method, the sound field separation technique was firstly used to separate the mixed sound field into the outgoing field coming from the target source and the incoming field coming from the disturbing source. Then the scattered component contained in the outgoing field was calculated by using the disturbing sound and the surface impedance of the target source. Finally, the sound field radiated by the target source in a free field was obtained by subtracting the scattered component from the outgoing field and was further used to reconstruct the sound field of the target source. The proposed method was numerically and experimentally testified and the results of both the simulation and the experiment demonstrated the validity of the proposed method.