Edge Processing for Calculating the Acoustic Radiation of Underwater Structures using the Boundary Element Method

Herein, the influence of edges on the results and the processing method of edge are studied when a boundary element is used to calculate the sound field of an underwater structure with edges. Because the edge is the intersection line of two different smooth planes, there is no definition of a normal vector at the edge of the edge; however, the boundary element method needs to give the normal vibration velocity of the node at the edge of the edge when calculating the sound field, and the node at the edge of the edge has a different normal vibration velocity for different elements. If they are separated, the dimension of the node's normal vibration velocity column vector will be greater than that of the node's sound pressure column vector. Herein, an approximation method for edges is presented on the basis of the idea of element superposition in the finite element method and the results of the program calculations of different processing methods are compared with the simulation results. The results show that the approximation method is in good agreement with the simulation results, and when the load is distributed on the edge, different processing methods have a great influence on the calculation results, with a maximum error of 9.56 dB.