The underwater acoustic scattering characteristics of cylindrical shells: Effect of a coating made of micro floating raft arrays

Coatings play a crucial role in the speed and stealth performance of underwater vehicles. While the cylindrical shell as an important component of the hull, studying acoustic scattering characteristics of the shell with coatings is an indispensable work. A novel anechoic coating is designed by introducing the floating raft mechanism to reduce the acoustic scattering of underwater vehicles. This paper comprehensively investigates the acoustic scattering characteristic of the cylindrical shell using the finite element method coupled with the boundary element method (FEM + BEM), particularly exploring the effect of the coating made of micro floating raft arrays. The results indicate that the coating can effectively absorb the detection sound waves and reduce the characteristic peaks of target echoes, due to the dissipation of acoustic energy by the coating element. Moreover, the acoustic scattering and the surface displacement of the cylindrical shell exhibit obvious attenuation. From the perspective of the stealth effect, the coating can reduce the mean target strength by an average of 7.17 dB (56% reduction in active sonar detection distance) in the case of monostatic detection. Even for the multistatic detection which can jointly receive the target echo, the coating still reduces the detection distance by 28%. Notably, the coating performs a better acoustic stealth effect than a homogenous layer, but its mass is only about half that of the homogenous one. In general, the coating can effectively reduce the acoustic scattering of the cylindrical shell and is of great significance for the lightweight design of anechoic coatings.