Abstract
Visualization of sound field helps us to intuitively understand mechanisms of various acoustic phenomena and therefore the technique is much effective for both of educational and engineering purposes. This paper presents some examples of sound field visualization based on numerical analysis. In order to analyze such complicated acoustic phenomena as reflection, diffraction and interference, the finite difference time domain (FDTD) method based on the wave theory is applied to the calculation. In the FDTD algorithm, all of the sound field is computed in discrete time steps and therefore transient acoustic phenomena can be easily animated. As an application of the numerical technique to environmental noise control engineering, sound reflection and diffraction around noise barriers with a variety of cross sectional shapes and noise propagation from depressed/semi-underground road structures are introduced in this paper.