The energy mobility method was developed in the medium frequency range, in order to predict the vibratory behavior of structures by frequency bands. In this study, one extend the approach to the case of vibroacoustic coupling between a fluid and a strcuture. The acoustic mobility for the fluid medium as well as the structural mobility for the structure are studied. The coupling surface is meshed in patches in order to reduce the problem to point energy mobilities. A numerical simulation was carried out in the case of a plate coupled with a parallepipedic cavity, where the influence of the number of patches and of the damping of the subsystems are studied. The kinetic energy of the plate, the power transmitted to the acoustic medium and the radiation efficiency of the structure are calculated and compared with a reference caculation (modal method) and with expreimental results. The criteria of meshing (size of patch compared to the wavelengths of the structure and the acoustic fluid) are determined before and after the critical frequency, to ensure a correct modeling of the coupling in a given frequency band. In order to take account of a structure complicated to model, a mixed calculation (use of measured mechanical mobilities and calculated acoustic mobilities) are also presented.
