Calculating research on estimating the scatter field distribution for underwater flat structure

According to enlarge frequency domain effectively, a Broadband Hybrid Calculating Model (BHCM) calculating acoustic scattered field originated from underwater flat object was put forward in detail based on Integral Equation Method and Geometrical Theory of Diffraction (including Uniform Geometrical Theory of Diffraction), which contained total work frequency range of underwater acoustics. Taking example for rectangular steel panel, numerical calculating and analyzing its underwater acoustic scattered field distribution in the frequency domain was carried out respectively on the condition of different acoustic incident angle. Two important conclusions were attained as follows: The results of two methods all complemented each other in the frequency domain, which were agreed well with one another in the mid-frequency range; and interrelated frequency value was dependent on the geometrical configuration of emitting source, receiving position and structure etc.. Acoustic scattered field distribution with frequency was dependent entirely on the interference effect between various wave components. Moreover, mirror scatter intensity was generally stronger than forward scatter for underwater structure with approximately rigid surface such as steel panel. It was shown that the before-mentioned BHCM was feasible and effective. Calculating precision and frequency width were improved effectively. These conclusions played a very important part in the scatter intensity estimation of the underwater structure target and free-field measurement and evaluation for acoustic material etc.