Multilevel algorithms for the fast evaluation of integral transforms in acoustics

The evaluation of integral transforms with oscillatory kernels is a common task in acoustic radiation problems. Integral transforms are generally computationally expensive. Depending on the properties of the kernel in the transform various methods exist to obtain a much faster evaluation. The aim of the present research is to investigate if the algorithm "Multilevel Multi-Integration" developed by Brandt [l], and successfully used in contact mechanics and multi-body interaction problems can also be used for acoustic problems. First the version of the algorithm is described aimed at the case of oscillatory kernels. Next, by means of a model problem, it is shown that at the expense of a small and controllable error that is independent of the wavenumber the algorithm facilitates fast and efficient computation even for high fiequencies. Even though the model problem considered is only one dimensional and thereby really very simple the results obtained are encouraging for further research.