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.

Topology optimization of bi‐material shell structures in shallow sea for reducing waveguide sound radiation

“…In the shallow sea, the sound radiation of vibrating underwater structures is susceptible to additional influences from the sea surface and seabed reflections, thus making the prediction of sound radiation in the shallow sea very complicated. In recent years, efforts have been devoted to studying methods for predicting the sound radiation of vibrating shell structures in the shallow sea waveguide, such as the wave superposition method, 1,2 the parabolic equation method, 3 the normal mode method, 4 the boundary element method, 5,6 and so forth, but little work has been done on the suppression of waveguide sound radiation. From either the perspective of military value or environmental protection, the control of radiated noise from shell structures in the shallow sea waveguide is of great significance.…”

A Method for Predicting Radiated Acoustic Field in Shallow Sea Based on Wave Superposition and Ray

“…Hence, this method is not appropriate for calculation speed at high frequencies. Qian proposed a method that combines the finite element method with the parabolic equation method to obtain cylindrical field data in the near field active region, and a complete far field solution in the far-field passive region, using the parabolic equation method [13]. The parabolic equation method is a recursive method, and far field calculation leads to error accumulation.…”