水听器基阵障板影响和阵列流形的边界元计算及实验验证

Calculation and verification of baffled hydrophone array manifold based on boundary element method

在考虑障板对水听器基阵影响的基础上,提出阵列流形获取的新方法,即阵列流形的边界元计算方法.首先将基阵障板视为一个散射体,然后通过计算散射体表面声场分布,求出基阵阵元位置处的声场响应,最后得到整个基阵的阵列流形.该方法可以获得与实验测量相吻合的阵列流形,避免了理想阵列模型失配的问题.对安装在半球形障板上的14元圆弧阵进行了仿真计算,并在消声水池进行了实验验证.仿真计算与实验结果表明,由于障板对水听器基阵的影响,阵元具有很强的指向性,导致理想阵列流形与实测阵列流形差异很大,利用本文方法可以获得与实测值相吻合的阵列流形.

A method for obtaining the hydrophone array manifold with the baffle effect is proposed and verified both by computer simulations and water-tank experiments. In this method, the array baffle is modeled as an acoustical scatterer and the boundary element method is used to calculate the sensor responses which include both the direct sound pressure and the scattered sound pressure at each sensor so as to obtain the array outputs to an incident testing sound wave. Then, the array manifold is obtained by accumulating the array output values at all sensors in all interested directions. By doing so, the effect of the array baffle can be included in the array manifold which will be more approaching the practical situation compared with that based on an ideal assumption without the scattering effect. An arc array with 14 piston transducers mounted on a rigid hemisphere was constructed and its array manifold was calculated using the proposed method. Meanwhile, experiments were conducted in an anechoic water-tank to measure the array manifold. Both the sensor directivities and array manifold were measured and compared with those obtained using the proposed method. The comparison between the sensor directivities shows that the results obtained based on the calculated array manifold have a similar tendency with the measurements. Furthermore, the optimized beam patterns of the constructed array were examined, and it can be seen that the design requirements of beam patterns which use the optimized weighting coefficient obtained from the array manifold calculated by the proposed method are well met in the constructed 14-element array. Using the proposed method, the array manifold can be predicated before the array is physically built and tested under practical conditions and the work in this article is very meaningful in designing practical sonar systems.