A STUDY OF FAST MULTIPOLE METHOD ON THE ANALYSIS OF 2D BARRIER

作者：Wu C H^*; Wang C N; Wu T D

来源：Journal of Mechanics, 2009, 25(3): 233-240.

• FMM
• Barrier
• Exterior acoustic problem and insertion loss

The purpose of this paper is to investigate, by the Fast Multipole Method (FMM), the sound field for a rigid barrier located on flat ground. At first the governed Helmholtz equation is transformed to a boundary integral equation, and then it is expressed as the summation of the integration of individual element. FMM is adopted to accelerate the speed of calculation. By an addition theorem, the kernels in the integral can be expanded to degenerate kernels, which separate the source point and field point. Compared with conventional BEM, FMM can reduce CPU time from O(N(2)) to O(N log(gamma)(N)) where N is the number of unknowns and gamma is a non-negative small number. Since the expansion is an infinite series, this number of terms is needed to satisfy the accuracy of computation and will be discussed. Finally, the effects of the rectangular, T-shaped, and Y-shaped barriers on noise reduction are also investigated.

• 出版日期2009-9