B. Masson, P.A. Nelson, E. Nienaltowska

The acoustic energy generated by a vibrating plate forming one surface of an enclosure is investigated. The flexible plate is excited by a 2-dimensional separated air-flow. This situation corresponds to the simplified model of a car side-window generating noise inside the vehicle compartment. The aerodynamic excitation by a separated flow is characterized by experimental wall pressure fluctuation measurements carried out in wind-tunnel. A model which represents this pressure fluctuation distribution is proposed in terms of cross-spectral density; these cross-spectra are defined in two distinct zones : (i) in the separation bubble or (ii) in the area after reattachment of the flow. This model forms the basis of the excitation used in calculating the acoustic energy in the enclosure. The acoustic energy generated in the cavity is calculated by assuming modal behaviours of the plate and the enclosure. The prediction is compared to measurements. It gives satisfactory results for the increase of noise due to a change of flow velocity, although the prediction of the levels resulting from a change in separation bubble length is not well estimated at frequencies above 500Hz.

DGLR/AIAA 14th Aeroacoustics Conference, 1992

Conference Paper

englisch

21,0 x 29,7 cm, 6 Seiten

DGLR-Bericht, 1992, 1992-03, DGLR/AIAA 14th Aeroacoustics Conference - Proceedings; S.403-408; 1992; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

aeroacoustics

Bibliothek

1992