Methods of experimental investigation of acoustic interaction between electroacoustical transducers in array

Abstract

Determination of acoustic loading conditions on projectors in underwater arrays is needed to predict the performance of the array. Nonuniform distribution of the acoustic loading over the radiating surface of the array is generated due to acoustic interactions between the projectors, and often causes performance degradation of the directivity patterns and the transmit frequency response. In the electromechanical equivalent circuit model of such an array, the influence of the neighboring transducers can be considered as the mutual radiation impedance that is inserted in series with the self-radiation impedance. The mutual radiation impedance depends on the configuration of the transducer, the mode of vibration, velocity distribution, and the geometry of the array. We present experimental techniques to determine the mutual radiation impedance as an intrinsic property of a given transducer and array configuration. Two experimental methods are presented: the Z method and the V method. The methods are based on the measurements of the input impedances and on the output voltages of the interacting transducers. For the two methods, analytical investigations based on the electromechanical equivalent circuit analysis will be presented along with supporting experimental results on cylindrical transducers. [Work supported in part by ONR 321SS Lindberg and BTECH Acoustics.]