A Near-to-far-field Transformation Method for Acoustic Scattering Problems

Kirchhoff integral was applied to acoustic scattering problems, and a near-to-far-fleld transformation method was developed for finite-difference time-domain (FDTD) method. Expressions for steady field and transient field were derived respectively. In addition to its efficiency and simplicity of implementation, it could reduce absorbing boundary condition (ABC) errors. For absolutely hard and absolutely soft objects, simulations were performed and results were given. A good agreement between this method and theoretical results was demonstrated, and accuracy of this method was higher than direct finite-difference time-domain (FDTD) method clearly. Validity and accuracy of this method were well proved.