21 pagesInternational audienceThe aim of this study was to present a deterministic model for approximating the vibrations and the acoustic pressure radiated when a thin elastic plate is immersed in a low Mach number flow of fluid. As a prelude to this study, a classical random model based on a wavevector integration technique was used. In the case of a low Mach number turbulent flow, the numerical study showed that the subconvective region of the turbulent excitation power spectrum contributes significantly to the response of the panel. A deterministic approximate model was developed, based on this behaviour of the system

International audienceOur study is focused on a phenomenon often encountered in flow carrying pipes, since flow instabilities caused by geometric features may generate acoustic signals and thereafter interact with these signals in such a way that powerful pure tones are produced. A modern example is found in the so-called "singing risers", or the gas pipes connecting gas production platforms to the transport network. But the flow generated resonance in a fully corrugated circular pipe may be silenced by the addition of relatively low frequency flow oscillations induced by an acoustic generator. Experiments reported here, aimed at investigating in more detail the coupling between the flow in the pipe, the acoustically generated flow oscillations and the emitted resulting noise, are performed in a specifically designed facility. A rectangular transparent channel using glass walls enables us to use optical techniques to describe in detail the flow field in the corrugation vicinity, in addition to more standard hot-wire anemometry and acoustic pressure measurements with microphones, with and without the acoustically generated low-frequency oscillations

International audienceThis paper considers the identification problem for 2D-structures by comparing a modal method with a new method based on the estimation of the dispersion equation in k-space. Both methods are validated by numerical simulation and by measurements based on an acoustic holography experiment

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