IMPLEMENTATION OF TRANSPARENT SOURCES EMBEDDED IN ACOUSTIC FINITE-DIFFERENCE TIME-DOMAIN GRIDS

The finite-difference time-domain (FDTD) method is a simple but powerf ul numerical method which has been used to perform a wide variety of c omplex simulations. One of the considerations in using this method is modeling the source of the incident field. When the physical source of acoustic energy is located within the FDTD grid it has typically been modeled as a ''hard'' source for which a source function determines t he field at a source node. One drawback of a hard source is that it ac ts itself as a scatterer. Moreover, its scattering cross section is di ctated by the spatial step size within the grid; thus, scattering is i ndependent of the underlying physical size of the source. In this pape r a scheme is presented that permits the creation of completely transp arent sources. These sources, although more expensive to implement tha n traditional hard sources, radiate the same field as a hard source, b ut do not scatter energy. (C) 1998 Acoustical Society of America.