A hybrid (boundary elements)-(finite elements)-ray-mode method for wave scattering by inhomogeneous scatterers in a waveguide

Wave scattering by inhomogeneous scatterers in a waveguide is studied using a new method that combines the hybrid ray-mode, boundary element, and finite element methods systematically in a single framework. This is a generalization of the previous work [I. T. Lu, “Analysis of acoustic wave scattering by scatterers in layered media using the hybrid raymode-(boundary integral equation) method,” J. Acoust. Soc. Am. 86, 1136–1141 (1989)]. The boundary element method is employed to model the interaction among scatterers and the coupling between interior and exterior of scatterers, the finite element method to formulate the interior responses of the scatterers, and the ray-mode method to provide Green's function of the waveguide. This hybrid combination optimizes the advantages of each method and hence, provides physical insights and numerical efficiency and accuracy. To further improve the computational efficiency, the Jacobi's iteration solution is employed.