Trailing Edge Noise Modelling of Flow over NACA Airfoils Informed by LES
Hussain Ali Abid, Anton P. Markesteijn, Sergey A. Karabasov
Abstract
View Video Presentation: https://doi.org/10.2514/6.2021-2233.vid In this study, the Wall Modelled Large Eddy Simulation (WM LES) is used to provide the input for several semi-analytical trailing edge noise models of the BANC III benchmark aerofoil flow problem for different angles of attack. The models considered herein include an improved TNO-type model that the authors [1] have recently developed with the XFOIL and RANS flow solutions. Hence the objectives of this work are two-folds : (i) to compare the acoustic models using a scale-resolving flow solution by LES as the input (ii) compare the noise predictions using LES Ffowcs Williams and Hawking (FW-H) scheme with Amiet trailing edge noise model. The study is carried out for two values of Reynolds number, Re = 1.0e6 and Re = 1.5e6 at three angles of attack, AoA = 0, 4 and 6 degrees for NACA0012 airfoil. We show that the LES solution agrees with the experiment for the time-mean velocity profiles. The computation of wall pressure spectrum profiles by the LES agrees well with the experiment. Moreover, the improved TNO model is also in good agreement with the LES. To assess the accuracy of the TNO models for the far-field noise predictions, their far-field noise spectra are compared with the fully numerical solution obtained using the FW-H method. The results show a good agreement between the improved TNO model and the LES-FW-H demonstrating the importance of accurate reconstruction of the main components of the trailing edge noise model, such as the vertical velocity spectra, including the turbulence anisotropy effects.