Reflected acoustic field above an aperiodic wall facing containing non-parallel cavities.

The purpose of this study was to determine the acoustic pressure field above a grating of non-parallel rectangular cavities. The Kobayashi Potential (KP) method has been used. This method was originally developed to study the diffraction of electromagnetic waves by thick slits. The sound field diffracted by each cavity is then expressed in a modal form. The total scattered field is given by the superposition of the different diffracted fields generated by each cavity in the grating. The coupling between the different cavities was taken into account. In the developed method, the different orientations of the non-parallel cavities have been modelled by combining rotations and translations between the local frame of each cavity and a reference frame. The results obtained by means of the model were compared with experiments achieved in a semi-anechoic room for two non-parallel rectangular cavities insonified by a spherical incident wave. The model was also compared to the finite element method. The validity of the model is supported by the agreement between the numerical and experimental results.