Two-dimensional finite difference-time domain simulation of moving multipole sources

Abstract

In this paper, the implementation of a moving multipole sound source in the two-dimensional (2D) finite difference-time domain method is described. The fundamental solution of the moving multipole source is theoretically derived by spatial differentiation of the fundamental solution of a moving monopole source in the 2D field. It was found theoretically that the directivity of a moving multipole source depends on the velocity and order of spatial differentiation. Numerical experiments were performed on the 2D sound field for moving multipole sources, and the results showed that the effect of the moving velocity on the amplitude of the multipole source is increased with the order of spatial differentiation. It was also found that the higher the order of spatial differentiation, the sharper the directivity in the moving direction and the larger the front-to-back ratio of the directivity. The present method can be accurately applied to the moving multipole sound sources.