Extension of Amiet's Theory for the Aeroacoustic Analysis of a Wing-Flap Configuration Including Acoustic Scattering

In this paper, the noise, generated aerodynamically, by a wing-flap conflguration and its propagation is investigated. At first the installation effects are studied using a simplified boundary element model, where the flap and the wing are considered to be, respectively, the only noise source and a scattering surface. Convective effects are not taken into account. The effect of the introduction of the wing in the sound field produced by the flap is investigated. The observed phenomena are related to the different impedance and the (non-)compactness of the flap and the wing. To calculate the power spectral density of the far-field acoustic pressure, an extension of Amiet's turbulence interaction noise model is translated to the trailing edge noise model. This includes an extension of the validity to the geometrical near-field and the introduction of the scattering in the model, using an acoustic transfer vector formulation. This model allows to calculate the power spectral density of the far-field acoustic pressure from the wall-pressure spectrum and the spanwise correlation length. The wall-pressure spectrum is modeled from RANS data using a statistical model and Corcos' model is used to obtain the spanwise correlation length. The results are compared with experiments. The proposed method is able to predict the correct order of magnitude and the frequency range where the influence of the flap is largest. For the considered listener's position, the influence of the flap is shown to be mainlyrelated to the consequence of the trailing edge noise of the flap. The scattering of the sound waves is only a secondary effect. © 2012 by the author(s).status: publishe