Direct simulation of acoustic scattering by two- and three-dimensional bodies

A method is presented for the determination of acoustic scattering from two- and three-dimensional bodies with arbitrary geometries and in the presence of a nonuniform flow. The technique is an extension of the impedance mismatch method, in which the scattering body is replaced with a region of different acoustic impedance. To minimize the oscillations at the body surface, an auxiliary problem, related to the conservative form of the linearized Euler equations, is posed and solved numerically. Example problems are solved for a cylinder, a Rankine oval, and a sphere in a fluid at rest and in the presence of a nonuniform mean flow. Comparisons are made with exact solutions, if they are available, and the agreement between the numerical and the analytical solutions is very good.