Energy based boundary element method for broadband high frequency sound fields

An acoustic boundary element method is formulated using the time-averaged intensity and mean-square pressure. A continuous distribution of uncorrelated broadband high frequency sources is used to represent the boundaries of the enclosure. Local correlation (within a fraction of a wavelength) is accounted for by assigning a directivity pattern to the infinitesimal sources. A further refinement of the method modifies the directivity function to account for specular reflections. Using these specially designed boundary elements removes the need to discretize the boundary at high resolution for high frequency sound fields. Instead, this method requires only one element per many wavelengths. Computational savings occur due to the reduction in the number of elements and the fact that the sources are broadband. Results are shown for a two-dimensional rectangular enclosure with two absorbing walls and excellent agreement with an exact analytical solution is obtained. Different interior source types, monopole versus dipole, were used and observations are made about the resulting acoustic field. © 2000 by L. Franzoni and D. Bliss. Published by the American Institute of Aeronautics and Astronautics, Inc.