基于二级迭代的局部近场声全息研究及实验

Research and experiment on patch near-field acoustic holography based on two-level iteration

为了有效减小传统近场声全息声场重建过程中的“窗效应”和准确利用有限测量孔径测量并定位潜艇的表面声源,提出一种基于二级迭代的局部近场声全息方法。首先,通过改进基于正交球面波的局部近场声全息方法,提出基于二级迭代的局部近场声全息方法;然后,仿真对比上述两种局部近场声全息方法的重构结果,研究外推误差和扩展测点数对重构精度的影响;最后,在消声水池中利用小孔径全息测量面进行基于二级迭代的局部近场声全息的实验研究。结果表明,基于二级迭代的局部近场声全息能大大减小有限测量孔径带来的“窗效应”和“孔径重复效应”误差,验证了该方法的优越性,可为水下大尺寸声源的近场声全息精确测量提供重要参考。

In order to effectively reduce the‘window effect’in the sound field reconstruction process of near-field acoustic holography(NAH)and accurately measure and locate the surface sound source of a submarine by using the limited measuring aperture,a patch NAH method based on two-level iteration was proposed.Firstly,patch NAH based on orthogonal spherical waves was improved,and a patch NAH method based on two-level iteration was proposed.Then,the reconstruction results of the two NAH methods were simulated and compared,and the influence of extrapolation error and extended measurement points on the reconstruction accuracy was studied.Finally,the experimental study of patch NAH based on two-level iteration was carried out in an anechoic tank using a small aperture holographic measuring surface.The results show that the patch NAH based on two-level iteration proposed in this paper can greatly reduce the‘window effect’and‘aperture repetition effect’errors caused by the limited measurement aperture,which verifies the advantages of the method and provides an important reference for NAH precise measurement of large size sound sources.