The utilisation of an adaptive 3D Gauss-Legendre quadrature in the simulation of sound propagation outdoors for sources with variable power distribution

This paper presents the utilisation of sound propagation outdoors using an adaptive 3D Gauss-Legendre quadrature method for generating contours for sound pressure levels, which is based on the diffused-field theory. The main advantage of this method is that it takes into account the geometry of the defined sound sources and produces the appropriate contours conforming to the shape of the sources. In addition, the variation in sound power distribution can also be simulated, where the appropriate distribution is decided from measurements. By modelling any source shape as an array of point sources which are in forms of lines, planes or 3D blocks, sound level at any position can be calculated using line, surface and volume integrals, respectively. This model is mostly suitable to be used for modelling huge sound sources such as power plants, or highways, and has been successfully used in the Environmental Impact Assessment studies involving noise issues.