ON THE BOUNDARY INTEGRAL EQUATION TREATMENT OF EXTERIOR ACOUSTIC PROBLEMS

The solution of acoustic problems via integral equations (IEs) is considered. Symmetrical evaluation of the resulting integrals is proposed. The possible reduction of the system matrix to complex symmetric form is considered. Applications of the proposed method to scattering by a soft as well as a hard sphere are presented. Another application to radiation from a uniformly vibrating sphere is also considered. To overcome the nonuniqueness problem, CHIEF method is used and Lagrange multipliers are employed to deal with the resulting overdetermined system to preserve the symmetry of the system matrix. The application of CHIEF via a close interior surface of a hard sphere with ka = 22.602185 illustrates the success of CHIEF at high frequencies (HF).