Research on the Equivalent Method of Complex Structures Based on a Few Simple Sources in Typical Shallow Sea Waveguide

The prediction of acoustic radiation from elastic structures in waveguides is a hot topic in the field of underwater acoustics. The equivalent source method, which equates the acoustic radiation of a structure to a series of virtual point sources, has become one of the mainstream methods for acoustic forecasting with the advantages of intuitive physical meaning and adaptability. However, due to the waveguide environment and the complexity of the elastic structure, the conventional method requires a large number of equivalent sources to match the acoustic quantities of the measurement surface, which limits the computational efficiency. In this paper, a complex structure equivalence method using a small number of simple sources is proposed. The method selects, one by one, the equivalence source with the best match between the radiated sound field and the measured sound pressure at far field among a large number of uniformly distributed equivalence sources, and discards the remaining equivalence sources with a high linear dependence to reduce the total number. Using a complex cylindrical shell in a typical shallow sea waveguide as an example, it is demonstrated that the proposed method can greatly reduce the number of equivalent sources while ensuring the accuracy of sound field prediction.