Computation of Trailing-Edge Noise Using a Zonal RANS-LES Approach and Acoustic Analogy

This paper document the evaluation of a zonal RANS-LES approach for the prediction of broadband and tonal noise generated by the flow past an airfoil trailing edge at a high Reynolds number. A multi-domain decomposition is considered, where the acoustic sources are resolved with a LES sub-domain embedded in the RANS domain. At the RANS-LES interface, a stochastic vortex method is used to ge nerate synthetic turbulent perturbations. The simulations are performed with the general-purpose unstructured control-volume code FLUENT. The far-field noise is calculated using the aeroacoustic analogy of FfowcsWilliams and Hawkings. The results of the simulation are compared with available acoustic and mean velocity measurements. The investigation demonstrates the ability of this approach to predict the aerodynamic and aeroacoustic properties of the flow. Two simulations are performed in order to address the s ensitivity of the results to the perturbation model. The comparison clearly indicates the critical influence of the model I. Introduction HIS study deals with numerical prediction of airfoi l trailing edge noise. Trailing-edge aeroacoustics is of importance in both aeronautical and naval applicati ons. The dipole sound produced by the edge scatteri ng of pressure fluctuations at a trailing edge is most of ten an undesirable effect. These pressure fluctuati ons are created by turbulent eddies as they convect over the trailing edge. This causes edge scattering of noise to the f ar field. This scattering mechanism can produce strong broadband and/or tonal noise which is radiated to the far fiel d. In this work, an Hybrid zonal RANS/LES unsteady CFD simulation is used to get a prediction of the acou stic sources, which are then use as an entry data of an acoustic propagation model. The case under study c orresponds to the recent experiment conducted by Kunze 1 . The trailing edge shape considered is identical w ith on of the trailing edge shapes previously investigated by Blake 2 .