The role of the resonance modes in the response of a fluid-loaded structure

International audienceThis paper is concerned with problems of fluid/structure interaction. The aim is to show how the resonance modes can be used to describe the response of a fluid-loaded structure (displacement of the structure and sound pressure in the fluid) for any kind of excitation (periodic, randomly dependent on time and space, or transient). First, the expression of the response of the system in terms of resonance modes is recalled. To compute the resonance modes, it is necessary to solve a system of equations in the harmonic regime. Several numerical methods are considered and a comparison of their respective efficiency is presented. Finally, two examples of applications are studied in detail. Namely, a thin plate excited by a turbulent wall pressure and a thin shell excited by a transient acoustic signal. For this last example, some experimental data are compared with numerical results