Sound radiation from a cylinder in shallow water by FEM and PE method

Abstract

There is no reliable research method for the acoustic radiation prediction of elastic structures in shallow water at present. Based on the finite element method coupled with the parabolic equation, the theoretical model for structure acoustic radiation in shallow water in low frequency is established in this paper. The vibro-acoustic characteristics of elastic cylinder influenced by with upper and lower fluid boundaries is calculated and analyzed. The study shows that when the cylindrical shell approaches the sea surface or bottom, the coupled frequency is higher or lower respectively than that of the shell immersed in the free field. When the diving depth reaches a certain distance range, the coupled frequency tends to be the same as that in free field. The acoustic field radiated from an elastic shell in Pekeris waveguide is similar to that from a point source in low frequency, but significant differences exist between them in high frequency. The structural source can’t be equivalent to a point source. The research results also show that the method proposed in this paper has good adaptability to the type of structure geometry and shallow water waveguide, and the calculation efficient and accurate are also very high.