Search Results

A new method called Adaptive Spectral Reconstruction (ASR) for the stochastic reconstruction of broadband aeroacoustic sources starting from steady CFD analyses is presented and applied to the evaluation of the noise radiated by a model automotive side mirror. The new approach exploits some ideas from both SNGR and RPM, and for some aspects can be considered as a sort of mixing between the two methods since it permits to reconstruct both the frequency content of the turbulent field (as done by SNGR) and the spatial cross correlation (as done by RPM). The turbulent field is reconstructed with a sum of convected plane waves, but two substantial differences are introduced in respect of SNGR. The first difference concerns the spatial variation of the parameters that define each wave, that depends on the wavelength of each wave, rather than being kept constant or related to the CFD correlation length.

In several applications of boundary element methods to acoustic and vibroacoustic analysis there is the need to model thin shells. Typically the classical Helmholtz integral equation is considered to breakdown for thin geometries and alternative approaches are used. In this paper it is however showed that the breakdown is not related to the Helmholtz integral equation itself, but instead is due to the discretization technique. An extension of the classical collocation approach that permits to bypass the thin shape breakdown is then proposed. The new discretization technique is referred as generalized collocation since the collocation point is no more placed on the integration surface but in the computational domain. Several numerical example are presented in order to show the accuracy and robustness of the proposed method.