The source simulation technique or related approaches like the multipole method, the superposition method, etc. are used for calculating the sound field radiated (or scattered) from complex-shaped structures. However, it is known that these techniques can lead to ill-conditioned systems of equations, and their numerical treatment requires extreme care. A new stabilized variant of the source simulation technique—called the full-field method—has been developed by using the exterior instead of the interior Helmholtz integral formulation or, equivalently, by expanding the sound field into special trial and weighting functions. These functions are chosen in such a way that the resulting matrix becomes more diagonally dominant. The full-field method is applied to the acoustic radiation from a pulsating sphere and to the high-frequency scattering from a cylinder and a nonconvex structure. The numerical results are compared with calculations obtained from other methods. It is shown that the improved method leads to better conditioned sets of equations which can be solved directly without singular-value decomposition, since the associated condition numbers are decreased strongly, in some cases by a few orders of magnitude.

Topics
Auditory system, Acoustic phenomena
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1999
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