An underwater acoustic transponder sound field modeling method based on simulated annealing algorithm

This study addresses the issue of self-generated sound interference in underwater acoustic transponders, which is caused by acoustic crosstalk leakage and shell scattering. A scattering sound field simulation model for underwater acoustic transponders is developed under the finite beamwidth acoustic wave incidence.

The transmitting and receiving ends are equivalently regarded as uniformly distributed multi-point arrays. The simulated annealing algorithm is employed to optimize the array parameters, which are then incorporated into the finite element acoustic field model to simulate the sound field while accounting for the directivity. The parameter optimization method for underwater acoustic transponders is developed by integrating the simulated annealing algorithm with the finite element acoustic field simulation method. The acoustic isolation within the specified working frequency range is enhanced by adjusting the positions of the transmitting and receiving arrays.

The results show that the overall directivity distribution of an underwater acoustic transponder is influenced by both the transducer's directivity and the scattering from the housing. The acoustic isolation exhibits a linear relationship with the installation distance when the transducer is positioned far from the housing. The acoustic isolation undergoes complex variations with distance under the influence of elastic waves when the transducer is close to the housing. The acoustic isolation generally decreases as the beam opening angle increases, while the operating frequency remains constant. When the beam opening angle is constant, the acoustic isolation fluctuates with frequency under the influence of the interference sound field near the shell. This parameter optimization method, which integrates the simulated annealing algorithm with the finite element method, allows for the optimal positioning of transmitting and receiving arrays in underwater acoustic transponders, thereby effectively enhancing the acoustic isolation at specified frequencies or across target frequency bands. A pool experiment was conducted using a simplified cylindrical shell model. The simulation results of acoustic isolation, which accounted for directivity, were consistent with the experimental measurements, confirming the effectiveness of the proposed sound field modeling methodology for underwater acoustic transponder.

This method enables automatic directivity fitting at the transmitting and receiving ends under specified frequency and beam opening angle conditions. It can be applied to the acoustic isolation design of underwater acoustic transponder structures.