Scattered acoustic field above a grating of non-parallel rectangular cavities

Geometric or acoustical irregularities induces acoustic scattering. In this paper, a generalization of the model proposed by Khanfir et al. [8] (Journal of Sound and Vibration 332 (4) (2013)) to determine the scattered acoustic field above gratings of parallel rectangular cavities is developed, addressing the case of gratings of non-parallel rectangular cavities. The results provided by the model were compared both to numerical results, obtained with the finite element method, and to experimental ones. The observed agreement between the analytical predictions and the numerical and experimental results supports the validity of the proposed model. The coupling between the different cavities was investigated, in order to attain an explanation for its dependence on frequency and on the spacing between cavities.