摘要
The application of BEM to calculate acoustic radiation from closed surface in an infinite acoustic medium has the advantages of less memory space, higher accuracy and faster calculating speed. However, the singular integrals and the nonuniqueness problem of surface helmholtz equation at characteristic frequencies should be dealt with. It is suggested in this paper that combination of the interior Helmholtz equation and its derivatives with respect to the coordinate components of an interior point forms an extra equation, in order to solve the problems of acoustic radiation at various frequencies with surface Helmholtz equation; on the area which includes singular point, the singular integrals are converted to ordinary ones by polar coordinate transformation. As an example, the acoustic radiation field of closed axisymmetric surfaces with prescribed surface velocity distribution is calculated in this paper.
The application of BEM to calculate acoustic radiation from closed surface in an infinite acoustic medium has the advantages of less memory space, higher accuracy and faster calculating speed. However, the singular integrals and the nonuniqueness problem of surface helmholtz equation at characteristic frequencies should be dealt with. It is suggested in this paper that combination of the interior Helmholtz equation and its derivatives with respect to the coordinate components of an interior point forms an extra equation, in order to solve the problems of acoustic radiation at various frequencies with surface Helmholtz equation; on the area which includes singular point, the singular integrals are converted to ordinary ones by polar coordinate transformation. As an example, the acoustic radiation field of closed axisymmetric surfaces with prescribed surface velocity distribution is calculated in this paper.
基金
The project supported by National Natural Science Foundation of China
