Numerical synthesis of aeroacoustic wall pressure fields over a flat plate: Generation, transmission and radiationanalyses

Abstract

The vibroacoustic behavior of simply supported plate excited by aeroacoustic pressure field is investigated. Based on analytical expressions of the Cross Power Spectral Density (CPSD) of an acoustic diffuse field and of a turbulent flow (Corcos's model), a new method is implemented to perform a numerical synthesis of aeroacoustic wall-pressure field. It is based on the Cholesky decomposition of the analytical CPSD matrices. Then using vibroacoustic FEM calculations, the contribution of each excitation field to acoustic radiation of the plate is analyzed. The inhomogeneity effect on the vibroacoustic behavior of the plate is also studied for a purely turbulent excitation. It is found that the spatial inhomogeneity effect is small on the averaged quantities such as the mean quadratic vibration velocity and the total radiated acoustic power. Finally, coherence function analysis is performed to investigate the relationship between radiated pressure field and excitation field. It is then emphasized the difficulties in well interpreting these last results especially when dealing with a turbulent component corresponding to an uncorrelated source of excitation.