In this paper, the approximate equation of Chapman's (real) effective depth for Pekeris guide is extended to the complex effective depth approximation whose real and imaginary parts explicate respectively the phas...In this paper, the approximate equation of Chapman's (real) effective depth for Pekeris guide is extended to the complex effective depth approximation whose real and imaginary parts explicate respectively the phase change and energy loss on reflection. It is shown that the homogeneous acoustic field, which comprises the complex effective depth approximation,closely reproduces the character of low modes at small grazing angles, and calculates effectively the acoustic field at longer ranges in shallow water. Application of the complex effective depth approximation can be extended to bottoms having two soft solid layers.展开更多
A coupled-mode sound propagation model with complex effective depth is presented,in order to involve the effect of branch line integral for acoustic field in a range-dependent waveguide.The equations of motion and con...A coupled-mode sound propagation model with complex effective depth is presented,in order to involve the effect of branch line integral for acoustic field in a range-dependent waveguide.The equations of motion and continuity are used to obtain the coupled equations,which satisfy boundary conditions in the waveguide with varying topography and contain one coupling matrix.Meanwhile,the couplings between discrete and continuous spectrum are dealt with based on complex effective depth theory.Numerical simulations show that the accuracy of transmission loss is improved by the coupled mode model when eigenvalues of trapped modes are located near the branch point.The acoustic field in a non-horizontally stratified waveguide can be calculated efficiently and accurately by this model,and the energy corresponding to trapped modes,leaky modes and branch line integral can be considered adequately.展开更多
文摘In this paper, the approximate equation of Chapman's (real) effective depth for Pekeris guide is extended to the complex effective depth approximation whose real and imaginary parts explicate respectively the phase change and energy loss on reflection. It is shown that the homogeneous acoustic field, which comprises the complex effective depth approximation,closely reproduces the character of low modes at small grazing angles, and calculates effectively the acoustic field at longer ranges in shallow water. Application of the complex effective depth approximation can be extended to bottoms having two soft solid layers.
基金supported by the Science and Technology Foundation of State Key Laboratory,China(9140C200103120C2001)the National Nature Science Foundation of China(11234002)
文摘A coupled-mode sound propagation model with complex effective depth is presented,in order to involve the effect of branch line integral for acoustic field in a range-dependent waveguide.The equations of motion and continuity are used to obtain the coupled equations,which satisfy boundary conditions in the waveguide with varying topography and contain one coupling matrix.Meanwhile,the couplings between discrete and continuous spectrum are dealt with based on complex effective depth theory.Numerical simulations show that the accuracy of transmission loss is improved by the coupled mode model when eigenvalues of trapped modes are located near the branch point.The acoustic field in a non-horizontally stratified waveguide can be calculated efficiently and accurately by this model,and the energy corresponding to trapped modes,leaky modes and branch line integral can be considered adequately.
