3D sound scattering by rigid barriers in the vicinity of tall buildings

The boundary element method (BENI) is used to evaluate the acoustic scatter ing of a three-dimensional (3D) sound Source by an infinitely long rigid ba rrier in the vicinity of tall buildings. The barrier is assumed to be non-a bsorbing and the buildings are modeled as an infinite barrier. The calculat ions are performed in the frequency domain and time signatures are obtained by means of inverse Fourier transforms. The 3D solution is obtained by mea ns of Fourier transform in the direction in which the geometry does not var y. This requires solving a series of 2D problems with different spatial wav enumbers, k(z). The wavenumber transform in discrete form is obtained by co nsidering an infinite number of virtual point sources equally spaced along the :: axis. Complex frequencies are used to minimize the influence of thes e neighboring fictitious sources. Different geometric models, with barriers of varying sizes, are used. The reduction of sound pressure in the vicinit y of the buildings is evaluated and the creation of shadow zones by the bar riers is analyzed and compared with results provided by a simplified method . (C) 2001 Elsevier Science Ltd. All rights reserved.