Experimental Validation of a Semi-Analytical Trailing-Edge Noise Model Including Broadband Scattering

Abstract

In most of industrial applications of rotating machines, the acoustic scattering by surrounding surfaces should be taken into account, as for cooling fans placed on the back of a cooling unit or aircraft Environmental Control Systems (ECS) fan located in a duct. The present paper proposes to combine an extension of Amiet's theory for trailing-edge noise with a BEM solver. The method is validated on an airfoil test case, investigated experimentally at the Université de Sherbrooke, in which a scattering plate is used as complementary scattering surface. The necessary inputs for Amiet's theory are obtained using a RANS computation of the test setup, from which the trailing-edge wall-pressure spectrum is reconstructed using a stochastic model. The comparison of the experimental results with the numerical method proves the necessity to take surrounding surfaces such as support plates into account as scattering objects. Then, the effect of the extra scattering plate is correctly reproduced compared to the free-field prediction, except in the low frequency range, where other sound mechanisms are probably neglected in the present approach.

Measurement and modelling of aero-acoustic installation effects in tractor and pusher propeller architectures

“…This generalization of Amiet's theory for trailing-edge noise has been validated on a stationary airfoil by Christophe et al [41].…”

Multi-disciplinary optimization of a contra-rotating fan

“…17 The trailing-edge noise has been treated by Rozenberg et al, 18,19 Winkler 20 and by Christophe. 14,21,22 The study of a hybrid method for the prediction of tonal wake-interaction noise from contra-rotating architectures is presented in the works of Carazo et al 23,24 Finally, the implementation of hybrid noise prediction methods in the optimization process of the L-1 fan presented in this paper is treated in Grasso's thesis. 25 The test case used in this work is the 4.2 m diameter low-speed contra-rotating fan of the VKI L-1 Eiffel-type wind tunnel, depicted in Figure 1.…”