Spectral infinite element method for boundary processing of sound field in two-dimensional shallow water waveguide
To solve the problem of low accuracy of the traditional infinite element method in truncated sound field boundary,a spectral infinite element method based on GR(Gauss-Radau)interpolation was proposed so as to deal with the effect of infinite boundary on sound field calculation with high pre-cision.A node transformation function from the natural coordinate system to the Cartesian coordinate system was constructed using the mapping function,to obtain the mapping Jacobian matrix of two coordinate systems.The GR interpolation based on the shape function was used to simulate the sound pressure of the element nodes,and the mapping Jacobian matrix was combined with the variational processing of the two-dimensional wave equation of the sound field and the integral expression corre-sponding to the infinite element was given to simulate the sound propagation at infinite distance in the actual waveguide environment.Compared with the analytical solution based on the image method and the traditional infinite element method,the results show that the proposed method is more consistent with the analytical solution,and the relative error is about 1%,and thus the effectiveness and accura-cy of the proposed method are verified.
two-dimensional shallow water waveguidespectral infinite elementGauss-Radau inter-polationboundary processingsound field calculation