Simulation Study on Acoustic Scattering Characteristics of a SCUBA Diver

Based on Kirchhoff approximation, a prediction method on the echo characteristics of a SCUBA diver was presented. Since a scuba diver needs to swing his large fins to overcome the water resistance caused by their diving equipment. As a result, the swing process of the fins may affect the backscattering characteristic significantly. Therefore, a 3D dynamic model of a SCUBA diver’s single swing fins was built. The motion process of the diver’s single swinging fins is split into 200 frames. The postures of the diver are different in the 200 frames, especially that of the fins. Six typical frames are selected among the 200 frames, which are frames 0, 40, 80, 120, 160, 200 and can represent the whole swing process. The echo waves and surface highlights of different postures at two incidence angles are compared. The study shows that for the head incidence (θ
0
= 0
⁰
)the acoustic contribution is mainly from body and fins, and the acoustic scattering echo amplitude of the fins varies periodically, since the cross section of the fins varies periodically as the diver swing. For left side incidence the acoustic contribution is mainly from the diver’s leg and air cylinder. Besides that, there is almost no change in the echo characteristics change little for different postures.