Modelling scattering from partially buried cylinders = Acoustic scattering from cylindrical objects embedded between two half-spaces/The computation of the scattered pressure field from a cylinder embedded between two half-spaces = The computation of the scattered pressure field from a cylinder embedded between two half-spaces with different densities

Abstract

1. A boundary integral equation method is presented for the computation of the acoustic field scattered from a cylindrical object which is totally within the water column, totally buried in sediment, or partially buried. The unknown field quantities within the cylindrical object (which may have internal cylindrical layering) are represented by a FourierIBessel series with unknown coefficients. The pressure field and its radial derivative on the exterior of the cylinder are related to this series and a system of equations for the unknown coefficients derived. This method is used to compute the spectral curves for the backscattered field as a function of cylinder burial. Some twodimensional full-field computations for scattering from cylindrical objects are also presented.

2. Various methods have been proposed for the solution of waveguide scattering problems(1-3). The last two references however are not applicable in the case of a scattering object embedded in an interface between two media. A semi-analytical solution is given to the problem of a cylinder embedded between two half-spaces with only a discontinuity in density (although the sound speed can be different within the cylinder). Although this is a particular subset of the general scattering problem, this method could provide useful benchmarks for more general numerical codes.