Elimination of internal resonance problem associated with acoustic scattering by three-dimensional rigid body

In this work, a simple and stable numerical method is presented, utilizing the method of moments (MoM), to eliminate the internal resonance problem associated with acoustic scattering by three-dimensional rigid body subjected to a plane wave incidence. The numerical method is based on the potential theory and combines the single layer formulation (SLF) and the double layer formulation (DLF). The scattering body is approximated by planar triangular patches. For the MoM solution of SLF and DLF, the basis functions have been defined with respect to the edges to approximate the unknown source distribution. These basis functions along with an efficient testing procedure generate accurate results at all frequencies, including the characteristic frequencies. Finally, the new solution method is validated with several representative examples. (C) 2004 Acoustical Society of America.