Abstract: The radiated sound field of a structure in shallow water environment is very different from that in free space due to the influence from the bottom and surface of the water. In order to analyze the radiated sound field of a large-scale structure in shallow water environment more efficiently and accurately, a fast boundary element method (BEM) is developed in this paper. The method adopts a wide-band fast multipole algorithm to accelerate the computation process. For the most time-consuming process of M2L/F2H transformation, the paper presents a criterion to classify the image sources in the uniform-layer Green's function into the near field and far field, so as to apply different solution schemes to reduce the amount of M2L/F2H transformations and thus improve the solution efficiency. Numerical examples verify the accuracy and efficiency of the method, and also show its engineering potential in shallow sea acoustic analysis.
Keywords: acoustic radiation; boundary element method(BEM); wide-band fast multipole algorithm; shallow water environment; chain of image sources