Effect of a free-surface fluid layer on vibroacoustic response of a plate

Jean-Michel Génevaux (1)

1 LAUM - Laboratoire d'Acoustique de l'Université du Mans

This experimental study points out the modifications of the behavior of a coupled system due to the introduction of a viscous fluid film between a gas volume and a vibrating plate. The tested configuration is composed by a cylindrical volume of gas with rigid walls excepted for one of the circular extremity witch is a thin aluminium plate. A rather low frequency domain is explored (30Hz-200Hz). The aim of this study is to reach to an optimization of this viscous fluid film in order to control the vibroacoustic behavior of the wall-film system and to dissipate maximum energy at chosen frequencies. For example, if water is used for the fluid film, surface waves appear at the fluid-gas interface if the vibrations are enough important. We observe a decrease of the natural frequencies mainly due to an added mass effect and also a decrease of the amplitude of the frequency response of the system compared to the response of a pure mass system. If a more viscous fluid is used for the film, for the same added mass, the decrease of the frequencies are equivalent to those observed with water, but less damping are observed : for the same vibration level of the plate, the surface-waves system do not appears and the fluid viscosity do not contribute to the system behavior. A simple model of the system will be also presented during the talk.

Mots clés: fluid layer; vibration; damping; Faraday instability; passiv treatment

Domaines: Vibrations [physics.class-ph]; Acoustique [physics.class-ph]

Jean-Michel Génevaux. Effect of a free-surface fluid layer on vibroacoustic response of a plate. 8th International Conference on Recent Advances in Structural Dynamics, Jul 2003, Southampton, United Kingdom. paper 152. ⟨hal-00351846⟩