Prediction of flow-induced sound and vibration: On different methods for introducing the TBL excitation in the vibroacoustic model

Marion Berton (1, 2, 3) , Laurent Maxit (2, 4) , Daniel Juvé (1, 4) , Christian Audoly (5)

1 LMFA - Laboratoire de Mecanique des Fluides et d'Acoustique
2 LVA - Laboratoire Vibrations Acoustique
3 DCNS - DCNS Group
4 CeLyA - centre Lyonnais d'Acoustique
5 DCNS

The modeling of the vibroacoustic response of a heavy fluid loaded panel excited by a turbulent boundary layer is investigated. The pressure fluctuations due to the Turbulent Boundary Layer (TBL) at the surface of the structure are characterized by cross-spectra which can either be expressed in the physical space or in the wavenumber space. Various models have been proposed in the literature to obtain closed form expressions of these spectra starting from global TBL characteristics. A difficulty to estimate the vibroacoustic response of the panel excited by TBL relies on the coupling of the deterministic vibroacoustic model with the statistical wall pressure fluctuations model. In the present paper, we study different techniques to achieve this coupling: (a), in the physical space; (b), considering an uncorrelated wall plane waves field; (c), using a reciprocity technique; (d), using realizations of the stochastic uncorrelated plane waves field. These techniques require calculating different transfer functions with a vibroacoustic model. For that, we use the Patch Transfer Function formalism (PTF). This approach allows us to couple the structure problem with the heavy fluid problem. The added mass effect of the fluid on the panel (i.e. fluid reactance) is taken into account in the modal frequencies of the panel whereas the acoustic radiation from the panel into the fluid (i.e. fluid resistance) is modeled using the real part of the patch acoustic impedances of the fluid domain. For validation purpose, the results of these vibroacoustic calculations are compared with a result from the literature for a test case composed of a simply supported rectangular thin plate immersed in water. Afterwards, the response of the panel excited by the turbulent boundary layer is predicted in the low and medium frequency domains using the four techniques described above. The response is characterized here by the velocity spectrum at one point on the plate. Convergence of the four techniques is studied. The results with different values of calculation parameters are presented and analyzed in order to find the optimal ones. We observe that the four techniques give very similar results for these optimal parameters. Finally, we discuss the interest of each technique.

Mots clés: Wall pressure fluctuaitons; TBL excitation; Fluid mechanics; Vibroacoustic model

Domaines: Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]

Marion Berton, Laurent Maxit, Daniel Juvé, Christian Audoly. Prediction of flow-induced sound and vibration: On different methods for introducing the TBL excitation in the vibroacoustic model. Acoutics 2013, Nov 2013, New-Delhi, India. p. 1281. ⟨hal-00994543⟩