An acoustic boundary element method based on energy and intensity variables for prediction of high-frequency broadband sound fields

Abstract

A boundary element method is formulated in terms of time-averaged energy and intensity variables. The approach is applicable to high modal density fields but is not restricted to the usual low-absorption, diffuse, and quasiuniform assumptions. A broadband acoustic energy/intensity source is the basic building block for the method. A directivity pattern for the source is derived to account for local spatial correlation effects and to model specular reflections approximately. A distribution of infinitesimal, uncorrelated, directional sources is used to model the boundaries of an enclosure. These sources are discretized in terms of boundary elements. A system of equations results from applying boundary conditions in terms of incident, reflected, and absorbed intensity. The unknown source power for each element is determined from this system of equations. A two-dimensional model problem is used to demonstrate and verify the method. Exact numerical solutions were also obtained for this model problem. The results show that spatially varying mean-square pressure levels are accurately predicted at very low computational cost.

The Wave-Matching Boundary Integral Equation — An energy approach to Galerkin BEM for acoustic wave propagation problems

“…Consider now the right-hand side of the Burton-Miller scheme (20). The second term (27) is identical to except that it involves , hence .…”

“…The BIE proposed herein could be described in similar language, but it is felt that this would cause confusion with the energy BEM described in [18][19][20]. Hence the name 'Wave-Matching', which reflects some properties of the BIE that are demonstrated in section 4 and was used for the same ideas in [61], is proposed instead.…”

“…This is of great interest in acoustics for example, where the audible bandwidth covers many octaves and applications such as auralisation require compatible modelling of all of this. Marching on a full wave solution for a few reflection orders until this scattering becomes chaotic, and then transferring that energy into a phase-less energy BEM such as [18][19][20], has the potential to be an efficient solution. Geometry of an exterior scattering problem Other Common Problems When Creating a PDF from a Postscript file -----------------------------------------------------------------You will need to convert your Postscript file to another format or fix the current Postscript file, then re-submit it.…”

“…Such a unification would be extremely impactful in acoustic modelling, where the full audible bandwidth covers many octave and wavelength changes from being large with respect to typical obstacle size to being very small, hence neither class of algorithm can presently meet all requirements. A parallel development is the application of boundary integral methods to model acoustic energy flow at high frequencies [18][19][20], again emphasising that BIEs are a framework that can be applied over a wide range of .…”

Comparison of vibrational conductivity and radiative energy transfer methods

“…In the field of acoustics, the so-called radiosity method [10,11,12,13,14] has been developed to allow the prediction of time reverberation in complex rooms beyond the validity of Sabine's formula. This method seems to stem from the field of radiative heat transfer and, more precisely, is analogous to the so-called standard procedure or view factor method.…”