Study of the acoustic oscillations by flows over cavities. Part 2. Sound reduction

Pascal Hémon (1) , Xavier Amandolese (2) , F. Santi (3) , J. Wojciechowski

1 LadHyX - Laboratoire d'hydrodynamique
2 IAT-CNAM - Institut AéroTechnique
3 Conservatoire Natl Arts & Metiers, Dept Math, F-75141 Paris 03, France

We present experimental results obtained with a deep cavity, like an Helmholtz resonator, excited by an airflow. The resonance under the action of the vortices generated in the shear layer is well described and quantified. The mounting of actuators, based on a few piezo-electric elements, allows to generate a series of two-dimensional vortices forced at a frequency which is different than the natural resonance frequency. The sound level in the cavity is strongly decreased and the broadband noise of the turbulence only remains.

Pascal Hémon, Xavier Amandolese, F. Santi, J. Wojciechowski. Study of the acoustic oscillations by flows over cavities. Part 2. Sound reduction. 2002 International Mechanical Engineering Congress, Nov 2002, New Orleans, United States. pp.917-923. ⟨hal-01026147⟩