ASA 124th Meeting New Orleans 1992 October

2pSA6. Acoustic harmonic scattering from cylinders using a new internal source density method.

Peter R. Stephanishen

Sudheer Ramakrishna

Dept. of Ocean Eng., Univ. of Rhode Island, Kingston, RI 02881

Two-dimensional acoustic harmonic scattering from rigid cylinders, which are symmetric about an axis, is addressed using a new internal source density approach. A least-mean-square error method is used to determine the internal monopole and dipole source density line distributions along the axis of symmetry of the cylinder by utilizing the rigid boundary condition at the cylindrical surface. The surface and exterior scattered pressure fields are then readily obtained from the source distributions. Numerical results are presented to illustrate the method for the case of plane wave scattering from circular and elliptical cylinders. Typical numerical results for the total surface and far-field scattered pressures are presented for plane wave scattering by a circular cylinder and compared with closed form solutions to illustrate the accuracy of the method. Finally plane wave scattering from elliptical cylinders are presented and discussed to illustrate the effects of aspect ratio, frequency, and angle of incidence.