Research and Experiments of Mutual Radiation Impedance Effect on Weighted Directivity

The effect on directivity of weighted array is investigated for the existence of mutual radiation impedance between underwater acoustic array elements. Based on the acoustic theory the mutual radiation impedance is introduced into the calculation of array radiation sound field, the weighted directivity function is modified, and then computer simulations and anechoic tank experiments are carried out for super directivity array. The results of computer simulations and anechoic tank experiments show that the array directivity is significantly affected at low working frequency in small array distance and the modified directivity function agree with the practical situation better in comparison to the conventional one.